You're using an outdated browser. Please upgrade to a modern browser for the best experience.
Crop Wild Relatives in Specific Cultivated Species: Comparison
View Latest Version
Please note this is a comparison between Version 3 by Jessie Wu and Version 2 by Jessie Wu.

Global climate change is one of the major constraints limiting plant growth, production, and sustainability worldwide. Moreover, breeding efforts in the past years have focused on improving certain favorable crop traits, leading to genetic bottlenecks. The use of crop wild relatives (CWRs) to expand genetic diversity and improve crop adaptability seems to be a promising and sustainable approach for crop improvement in the context of the ongoing climate challenges. The crop wild relatives in specific cultivated species such as tomato, alfalfa grain legumes and woody perennials are discussed. 

  • tomato
  • salt stress
  • woody perennials
  • crop wild relatives
  • drought stress
  • grain legumes
  • abiotic stress
  • resilience
  • alfalfa

1. Tomato

Cultivated tomato (Solanum lycopersicum) is one of the most economically important crops also used as a model crop for vegetables [1]. It is a diploid species with a haploid set of 12 chromosomes and genome size of approximately 950 Mb [2]. There is a plethora of tomato wild relatives with specific traits, including Solanum pimpinellifolium, Solanum nigrum, Solanum pennelli, Solanum peruvianum, and Solanum chilense [3] among others, which have shown tolerance to different abiotic stresses and adaptation mechanisms to different and extreme environmental conditions. Indicatively, Solanum chilense can grow in the desert due to its long primary roots and its extensive secondary root system. Moreover, it has been proved that Solanum pennellii utilizes water availability in soil efficiently under drought conditions, while Solanum cheesmanii and Solanum peruvianum can grow in salty coastal areas due to different adaptation mechanisms they have developed on their root systems [4]. The exploitation of such huge genetic diversity existing in CWRs in tomato breeding efforts for abiotic stress tolerance can provide new varieties with an enormous reservoir of adaptive traits. Several examples of tomato CWRs regarding their tolerance to abiotic stressing factors are mentioned below and reported extensively in Table 1.
Table 1.
Crop wild relatives (CWRs) of the respective crop genera that present tolerance to abiotic stresses.
Species Type of Tolerance Wild Species Source
Tomato drought tolerance Solanum habrochaites (syn. Solanum hirsutum) [5]
    S. pennellii [6]
    S. pimpinellifolium [7][8]
    S. cheesmanii [9]
    S. chilense [10]
    Solanum sitiens [11]
  salt tolerance S. pennellii [12][13]
    S. pimpinellifolium [12]
    S. hirsutum (syn. S. habrochaites) [14]
    Solanum parviflorum [15]
  heat tolerance S. habrochaites (syn. S. hirsutum) [5]
    S. pennellii [16]
    S. pimpinellifolium [16]
    S. cheesmanii [17]
    Solanum chmielewskii [18]
Alfalfa drought, salt,

cold tolerance		 Medicago truncatula [19]
Medicago ruthenica [20][21]
Medicago polymorpha [22]
Medicago falcata [23]
Cowpea drought tolerance Vigna exilis [24]
    Vigna heterophylla [25]
    Vigna kirkii [25]
    Vigna trilobata [24]
    Vigna riukiensis [24]
  heat tolerance Vigna hainiana [25]
    Vigna stipulacea [25]
  salinity tolerance Vigna luteola [25]
    Vigna marina [26][27]
    Vigna nakashimae [28]
    Vigna riukiuensis [28][29]
    Vigna trilobata [28][29]
    Vigna vexillata [25]
    Vigna trilobata [25]
  extreme types of soils Vigna minima [30]
    Vigna indica [31]
  water-logging tolerance Vigna vexillata [32]
Groundnut drought tolerance Arachis dardani [33]
    Arachis diogoi [34]
    Arachis duranensis [35][36]
    Arachis glabrata [37]
    Arachis magna [38]
  heat tolerance Arachis diogoi [34]
    Arachis duranensis [39]
    Arachis glabrata [40]
    Arachis ipaensis [39]
  cold tolerance Arachis duranensis [41]
    Arachis glabrata [37]
    Arachis paraguariensis [40]
  salinity tolerance Arachis diogoi [34]
    Arachis duranensis [36][41]
    Arachis glabrata [37]
  UV-exposure tolerance Arachis stenosperma [42]
Apple drought tolerance Malus prunifolia [43]
    Malus sieversii [44][45]
  heat tolerance Malus prunifolia [46]
    Malus sieversii [45]
  cold tolerance Malus prunifolia [44][45]
    Malus baccata [47]
    Malus sieversii [45]
Cranberry cold tolerance Vaccinium oxycoccos [48]
Grapevine drought tolerance Vitis yeshanensis [49]
  salt tolerance Vitis sylvestris [50]

1.1. Drought Stress Tolerance

Drought is an important limiting factor of crop production, especially in the context of global climate change. Several drought-tolerant (quantitative trait loci) QTLs or genes have been identified in tomato CWRs, but they have not been proven as successful as expected [51]. The development of advanced backcross introgression lines (BILs) provides a useful alternative method for the transfer of drought-tolerant genes [52]. Eshed and Zamir [53] presented a novel population consisting of 50 introgression lines originating from a cross between the green-fruited species, Lycopersicum pennellii, and the cultivated tomato (cv M82). Since then, many researchers used these lines in breeding programs to investigate promising genes and QTLs for drought stress among other stress factors, concluding that despite the difficulties, this approach may be the best strategy if no other effective breeding alternatives are available [52][54][55]. In fine-mapping drought tolerance within several introgression of S. pennellii and the parental line cv M82, cleaved amplified polymorphic sequences (CAPS) markers have been developed and screenings for root morphological traits performed to identify plants putatively inheriting a root architecture compatible with drought tolerance [54].
Advances in genetics and genomics have improved the understanding of structural and functional aspects of the tomato genome [55]. Moreover, genes with high homology to FQR1-like NAD(P)H dehydrogenase, known for its antioxidant properties, were also identified in S. pimpinellifolium [56]. Further study of these unique orthologues might give insight into the adaptation of S. sitiens, another drought and salt-tolerant tomato CWR in water-limited environments [11]. In the future, new technologies, such as CRISPR-Cas9, could enable the transfer of genes underlying drought tolerance from tomato CWRs to cultivated tomato varieties [8].

1.2. Salt Stress Tolerance

Tomato is susceptible to salt stress, which leads to substantial productivity reduction. CWRs, such as S. pimpinellifolium, S. pennellii, and S. chilense, can tolerate these adverse conditions of salinity. Recently, the genome of S. pimpinellifolium has been sequenced [56] and revealed an interesting finding for genes associated with abiotic stress, such as salinity. Additionally, further study of some genes from S. chilense associated to abiotic stress [57] can be a starting point to annotate new genes and the applicability for a genome-wide analysis. Salinas-Cornejo et.al. [58] provided information that expression levels of SlAREB1, a member of the abscisic acid-responsive element binding protein (AREB), are correlated with the degree of drought and salt tolerance presented by transgenic tomato plants. They also identified an important number of genes regulated by SlAREB1 protein and associated with both abiotic and biotic stress responses.
Furthermore, many QTLs have been mapped for salt stress tolerance during the different growth stages in tomato, For instance, (a) at the seed germination stage, indicating S. pennellii and S. pimpinellifolium as potential tolerant sources of salt tolerance with several QTLs mapped [12][59], and (b) at the vegetative and reproductive growth stages with regard to fruit number, fruit weight, and fruit yield, several QTLs from S. pimpinellifolium [60][61] have been annotated. The reported QTLs and major associated genes would be possibly transferred to suitable genetic backgrounds of cultivated tomato genotypes to develop tolerant cultivars against salt stress [62].

1.3. Heat/Cold Stress Tolerance

Cold stress reduces uptake of water and nutrients in plants, leading to nutrient starvation within cells. Furthermore, heat stress leads to marked alterations in the physiology and metabolism of plants [63]. On the other hand, the characterization of important gene families and their relative expression under low and high temperatures have been reported for a wide variety of plants [64][65][66]. Studies focusing on tomato chilling responses revealed over-expression of the chloroplast gene family encoding heat shock proteins (HSPs) and concomitant reduction in ROS and lipid peroxidation, reflecting an increase in photosynthetic performance [67]. Tolerance mechanisms utilized by plants against chilling conditions involve the increased expression of genes that reduced the intensity of oxidative damage induced by cold stress [68]. Catalase, a crucial ROS-scavenging enzyme, eliminates hydrogen peroxide in the cell cytoplasm and contributes to the scavenging of H2O2 [69]. The seed priming-induced method increases CAT activities for several species studied, including tomato [67]. Further investigation into tomato CWRs for more genes that induce tolerance mechanisms for cold and heat stress and their exploitation in cultivated tomato breeding programs is a promising approach for solving problems caused by extremely low/high temperatures.

2. Grain Legumes

Grain legumes are often cultivated in marginal lands and confront unfavorable environmental conditions [70] that prevail in these areas. Typically, marginal areas are characterized by poor soil fertility and are usually prone to abiotic stresses, such as drought and salinity [71]. Breeding for tolerant grain legume genotypes to various abiotic stresses is therefore of primary importance, especially given the impending climate change. In this review, we focused on progress regarding CWRs assessment and implementation in breeding of two summer grain legume species, namely cowpea (Vigna unguiculata (L.) Walp.) and groundnut (Arachis hypogaea L.), as the climate change effect becomes more and more apparent in Europe; thus, they consist of crops with increasing rates of cultivation in the area [72].

 

2.1. Cowpea

Cowpea (Vigna unguiculata (L.) Walp.) (2n = 2x = 22) is a primarily autogamous, annual, grain legume domesticated in Africa in two parallel primary centers of origin [73][74][75][76]. It belongs to the genus Vigna which comprises about two hundred different species [77], among them over one hundred wild species [30][78][79]. A plethora of endemic cowpea wild types are still present in Africa [80] that are considered progenitors of cultivated cowpea [73] and contain valuable genetic material for breeding. Recently, African cowpea genome size was revised and estimated through cytometric studies on 640.6 Mb [79], while for asparagus bean (Vigna unguiculata ssp. sesquipedalis) a 632.8 Mb genome size is reported [80]. The difference between the two species genome size is mainly because of changes in the Gypsy retrotransposons contained [79].
Genes of the NAC family (VuNAC1, VuNAC2) [81], WRKY family (VuWRKY) [82], DREB family (VuDREB 2A) [83], pUCPs family (VuUCP1a, VuUCP1b) [84], Aox family (Vu Aox1, Vu Aox2) [85], HSP family (VuHSP17.7) [86][87], and LEA family [88] have been found among others to be differentially expressed in cowpea under abiotic stresses conditions, promoting abiotic stress tolerance.

Drought and Other Types of Stress Tolerance

Cultivated cowpea types have proved more prone to drought than the wild Vigna material [89]. High levels of drought tolerance have been reported for V. heterophylla and V. kirkii, while high-temperature occurrence tolerance have been reported in V. hainiana and V. stipulacea [25]. V. exilis, V. trilobata, and V. riukiensis have also been characterized as drought tolerant [24] as they express genes related to ABA biosynthesis and proline biosynthesis. Antioxidant capacity, accommodation of small leaves that increase the heat flux from the leaf surface, and hairiness of leaves consist of mechanisms for drought and heat tolerance of wild Vigna species [89]. Vigna riukiuensis is especially characterized by a deep and wide root system and small size of leaves that renders it a heat-tolerant species [28][29][30]. Wild Vigna germplasm materials, such as V. minima and V. indica [90], have also been found to be tolerant to acidic and limestone type of soils, and V. vexillata has been found to be a water-logging-tolerant wild species [91]. Vigna wild species tolerance to abiotic stresses is presented in Table 1.

Salt Stress Tolerance

Salinity tolerance has been reported for V. luteola, V. marina, V. nakashimae, V. vexillata var. macrosperma, V. riukiuensis, and V. trilobata [26][27][28][29]. Salt tolerance mechanisms of wild cowpea species include Na+ exclusion, increased antioxidant ability, osmotic regulation, and changes in hydraulic conductance [92]. Accessions of wild species of V. nakashimae and V. riukiuensis express salt tolerance through Na+ filtration by roots and stems to prevent uptake into leaves and accumulation of large Na+ amount throughout the whole plant, respectively [28]. Through screening of Asian Vigna wild types, Naito et al. [24] led to the identification of genes related to salt stress response, such as sodium and potassium transporters, while salt-tolerant species presented active transcription of SOS1 and SOS2 genes. They also found genes related to salt stress that are related to ABA biosynthesis [24]. Vigna marina was found actively to transcribe sodium transporters and antiporters (NHX1 and NHD1), while NHX2 and HKT1 potassium transporters were transcribed by V. riukiuensis [24], leading to increased salt tolerance. Furthermore, lower base water potential of seeds compared with other Vigna species renders its seeds able to germinate in soils with increased salt content [27].
Finally, QTLs for salt tolerance were found in V. marina ssp. oblonga, which is a salt-tolerant type, that could be further used in introducing salt tolerance in cultivated cowpea [26]. However, attempts to cross the cultivated African cowpea with salt-tolerant [92] V. vexillata, the closest species to cowpea [93], have so far proved fruitless [94][95] despite the creation and characterization of an interspecific hybrid created by Gomathinayagam et al. [96]. As wild Vigna relatives are interesting material for the improvement of the cultivated Vigna [31][97], the continuation of the crossing effort is considered critical. Wild cowpea germplasm variation should be more intensively exploited [98] as it consists of a valuable source of abiotic stresses tolerance [99].

 

2. 2. Groundnut

Groundnut (Arachis hypogaea L.) or peanut (2n = 4x = 40) (AABB) is an annual grain legume and oil crop with a primarily self-pollinated mating system [100]. As it was formed after a hybridization between diploid species, A. duranensis (AA) and A. ipaensis (BB), followed by chromosome doubling [101], it has a wide gene pool [97][100]. Cultivated groundnut genome size is approximately 2.7 Gb, very similar to the sum of its two wild progenitors, A. duranensis (1.25 Gb) and A. ipaensis (1.56 Gb) [102]. Crop wild relatives of groundnut constitute a valuable but underutilized genetic source due to difficulties in introgression of genes into the cultivated species, owing to ploidy discrepancy among groundnut (allotetraploid species) and the wild relatives (mainly diploid species) [100][103] as well as sterility barriers [104]. Drought and high temperatures constitute the major abiotic stress factors for groundnut, whereas salinity tolerance is important in many areas [100].
Plant heat shock factors (HSFs) play a key role in groundnut response to various environmental stresses by regulating the expression of stress responsive genes, such as heat shock proteins (HSPs), dehydration responsive element-binding proteins (DREBs), late embryogenesis abundant proteins (LEA), and abscisic acid response element-binding proteins AREB [105]. CRT element-binding factors (CBFs) were also found to respond to various plant stresses [106][107][108][109].
Dehydration responsive element-binding protein (DREB) genes are reported to increase transpiration efficiency under water-limiting conditions (AtDREB1A, DREB1A) [110][111][112]. A DREB factor, namely PNDREB1, was also identified by Zhang et al. [113] to respond to low temperatures and osmotic stress. However, no response of this gene to salinity has been observed. An ABA synthesis gene, AhNCED1, and three dehydration-induced transcription factor genes were also found to be differentially regulated in groundnut under drought conditions [114].
Ethylene-responsive factor (ERF) regulates gene expression associated with abiotic stress tolerance [115] through the activation of ABA [116]. In groundnut, ERF genes were found to be induced after the application of abiotic stresses, such as drought, cold, heat, and salinity [115]. Additionally, AhLea-3 has been reported to be related to salt tolerance [117]. AtNHX1, a vacuolar Na+/H+ antiporter in Arabidopsis thaliana, mediates the transport of Na+ and K+ into the vacuole, enhancing salt tolerance [118]. Overexpression of the AtNHX1 gene was also found to improve salt and drought tolerance in transgenic groundnut [119]. Moreover, stress-inducible expression of AtHDG11 in transgenic peanut lines resulted in up-regulation of various stress responsive genes (LEA, HSP70, Cu/Zn SOD, APX, P5CS, NCED1, RRS5, ERF1, NAC4, MIPS, Aquaporin, TIP, ELIP) leading to improved drought and salt tolerance [120].

Drought Stress Tolerance

Wild groundnut species genes that are drought stress involved are discriminated into two groups: (i) genes that are plant cell protectors and act as upstream regulators and (ii) regulatory genes, such as transcription factors, implicated in the ABA pathways [121]. Tolerance to abiotic stresses has been recorded in A. stenosperma [103], while Guimarães et al. [122] identified a remarkable number of transcription factors and genes related to drought stress in a peanut ancestor, A. duranencis. In the same wild species, a great number of differentially expressed genes were recorded under drought stress treatment [123]. Arachis duranensis tolerance to drought is based on restricted plant transpiration behavior upon stress implementation. Several characteristics associated with drought response were detected in A. dardani, such as leaf angle adjustment [33], and in A. duranensis high photosynthetic rate, stomatal conductance, transpiration rate, lower leaf temperature, and vapor pressure [35]. Drought-responsive candidate genes, such as Expansin, Nitrilase, NAC, and bZIP transcription factors, displaying significant levels of differential expression during stress application in A. duranensis and A. magna were identified, while they possess drought response mechanisms, including signal transduction, primary metabolism, hormone homeostasis, and protection of cellular structures [38]. More recently, genes encoding the drought-responding fatty acid, desaturase, were also identified in groundnut progenitors and presented to be homologous to peanut [124].

Heat/Cold Stress Tolerance

A heat-tolerant genotype of the wild species A. glabrata (A. glabrata 11824) and a cold tolerant genotype of A. paraguariensis (A. paraguariensis 120142) were identified by [40] through screening of thirty-six different wild genotypes. A total number of sixteen and seventeen heat shock transcription factors were found in A. duranensis and A. ipaensis, respectively, that are commonly known to protect plants from abiotic stresses [39]. Non-specific lipid transfer proteins (nsLTPs) that are known to transfer various lipid molecules between lipid bilayers in plants were identified in A. duranensis that respond to salinity and low-temperature conditions [36]. Tolerance assessed in Arachis wild species is presented in Table 1.

Combined Abiotic Stress Tolerance

Genes and transcription factors identified in Arachis wild species were in many cases responding to a complex of abiotic stresses. In wild groundnut A. diogoi, the expression of gene AdDjSKI was induced under heat, salinity, drought, and osmotic stresses and seems to be related to the photosynthetic mechanism of plants [34]. Recently, NAC transcription factor genes that are implicated in salt and drought responses of many plant species were identified in A. hypogaea as well its progenitors [41]. Valine-glutamine sequences that are related to environmental changes were also assessed in wild species, A. duranensis, A. ipaensis, and A. monticola. Genes of the mTERF family that mediate acclimation of plants to adverse environmental conditions were also identified in A. duranensis and A. ipaensis that were distributed over their ten chromosomes [125]. Transcriptomic analyses on the wild and highly adaptable A. glabrata revealed a plethora of transcript factors to be expressed under drought, salt, and cold stress implementation [37]. Finally, a great number (4513) of differentiated expressed genes (DEGs) was also recorded to be expressed under UV exposure and dehydration in A. stenosperma by Martins et al. [42], mainly associated with cell signaling, protein dynamics, hormonal and transcriptional regulation, and secondary metabolic pathways. These genomic findings provide useful tools for the further improvement of the species in abiotic stresses.
Synthetic amphidiploid and autotetraploid groundnuts were created to overcome genetic barriers of groundnut breeding [126]. Synthetic groundnut germplasm was mainly screened for biotic stress tolerance [127][128][129][130][131] and introgressed into cultivated material [132][133]. The variability that synthetics often express could possess hidden alleviation for abiotic stress tolerance that remains mostly unexploited. Stress tolerance of the tetraploid groundnut species is not always expressed in the same way as their wild diploid relatives [129]. Bera et al. [134] found two interspecific derivatives, (NRCGCS-296 (J11 x A. duranensis)) and (NRCGCS-241 (GG 2 x A. cardenasii)), that presented high germination tolerant index and promptness index while applying 250 mM NaCl and therefore were characterized as tolerant to salinity. WRKY and Na+/H+ genes were also assessed as responsible for inducing tolerance in the synthetic hybrids. 2.3. Alfalfa

2.3. Alfalfa

Legume plants make up one-third of the world’s major agricultural yield and are significant sources for human and animal consumption [135]. Medicago sativa (alfalfa), the most significant legume fodder, has been cultivated in more than 80 countries with a total surface area of 32 million hectares available globally [136]. Alfalfa is regularly exposed to harsh environments in the major regions of the world, including drought in Argentina and northern China, cold temperatures in Russia and Canada, and saline/alkaline soils in California, America, and Australia. Environmental stress in these places has had a significant impact on alfalfa productivity and quality [137][138][139][140]. Long-term domestication of cultivated alfalfa may have resulted in decreased tolerance for severe abiotic and biotic stressors because of the emphasis placed on features linked to high production. The key to accelerating M. sativa’s breeding is the use of genetic variants underlying agronomic features in wild relatives close to the cultivated Medicago [141]. Therefore, genomic data from wild species might offer important insights for enhancing features linked to the adaptability to stressful situations in legume forages. For breeding alfalfa varieties with great tolerance to environmental challenges, genetic resources rich in alleles adaptable to severe environments are highly needed. The genus Medicago includes wild species that are closely related to M. sativa, including Medicago truncatula (a model plant for legumes) [19], Medicago ruthenica [21], Medicago polymorpha [142], and Medicago falcata [23]. In the present study, emphasis was given to one of the most promising wild species. Medicago ruthenica (L.) Trautv. is a natural grassland plant that is widely distributed in hillsides, mixed grass steppes, and meadows in Siberia, Mongolia, and northern China [143]. It is an allogamous diploid (2n = 2x = 16) perennial legume fodder with re-assembled genome of 904.13 Mb [144]. It is very closely related to alfalfa [144]. Long, chilly winters and dry, saline soils limit M. ruthenica’s distribution area [145]. As a result, M. ruthenica must have developed powerful defenses to withstand the harsh conditions, such as drought, subfreezing temperatures, and saline soil. M. ruthenica is thought to be a rather uncommon species among Medicago species that is highly adapted to stressful conditions, and whose prospective applicability is favorably assessed in low input environments. The roles of differently abiotic stress-related expressed genes, such as AP2/ERF family, MYB/MYB-related family, bZIP, bHLH, and WRKY from M. ruthenica in stress resistance have not been fully elucidated [146][147]. These genes play important roles in many different regulation mechanisms of diverse abiotic stresses. Numerous studies have demonstrated the transcription factors, bZIP, WRKY, and AP2/ERF, have a role in the transduction of the ABA signal and stress responses in plants through their interaction [72].

2.3.1. Drought Stress Tolerance

2.3.1. Drought Stress Tolerance

In addition to being a close relative of alfalfa, M. ruthenica is a perennial species with a similar genome size, life cycle, and pollination system. More importantly, because it is a wild species with numerous accessions that is found widely in arid and/or semi-arid areas, it is highly tolerant to drought stress. As a result, it has been used as parental material to breed alfalfa cultivars that are tolerant to environmental stress, which has improved alfalfa tolerance to adverse environments [20][144]. M. ruthenica’s drought tolerance was compared to that of M. truncatula, M. varia, M. falcata, and two cultivars of alfalfa byWang et al. [21]. Among the tested legume species, M. ruthenica seedlings showed the greatest resilience to drought stress. The strongest resistance of M. ruthenica to drought stress among the examined legume forages was demonstrated by the fact that while exposure to drought significantly reduced the survival rates of other legume forages, the same treatment had little impact on the survival rates of M. ruthenica seedlings. Additionally, it was found M. ruthenica and M. truncatula, respectively, have 37 and 23 of the AP2/ERF family, drought-responsive TF genes. Twenty-one and ten drought-responsive TFs from the MYB/MYB-related family in M. ruthenica and M. truncatula, respectively, were discovered [20]. The knowledge of M. ruthenica’s genome and the discovery of its resistance genes can help to improve agronomic traits linked to high yield and exceptional tolerance to environmental stress using a molecular breeding strategy.

2.3.2. Salt Stress Tolerance

2.3.2. Salt Stress Tolerance

Abiotic stresses, such as salt stress, have an impact on plant productivity and growth. Medicago ruthenica exhibits exceptional stress resistance, making it a valuable gene resource

for enhancing other plants’ stress tolerance. Two differentially expressed genes (DEGs) (MrERF, MrbZIP) from M. ruthenica have not yet been thoroughly characterized in terms of their functions in salt tolerance. Wu et al. [146]  demonstrated the transgenic lines of tobacco over-expressing these genes grew more successfully than wild types exhibiting greater height, more branches, and earlier flowering. Additionally, compared to wild type tobacco, the seed yield of transgenic tobacco was considerably higher. Furthermore, it was demonstrated MrERF or MrbZIP may be rapidly expressed in leaves by NaCl since three transgenic tobacco lines outgrew wild in terms of leaf growth, with MrERF and MrbZIP having the best growth. Thus, MrERF and MrbZIP can increase the germination rate of Medicago under salt stress because they greatly increased the germination rate of transgenic tobacco lines. Plant height, biomass, and the root-to-shoot ratio of transgenic tobacco expressing MrERF or MrbZIP all significantly increased when exposed to NaCl. Lastly, under salt stress, MrERF and MrbZIP transgenic lines’ roots length grew by approximately 2.03 and 2.19 fold of wild type, respectively  [147].

2.3.3. Cold Stress Tolerance

2.3.3. Cold Stress Tolerance

M. ruthenica is also an important resource for the genetic improvement of alfalfa in response to cold stress. Shu et al. [145] performed an RNA-Seq analysis of the M. ruthenica transcriptome in response to cold stress using high-throughput nucleotide sequencing. A total of 894 genes were identified that responded to cold stress. Expressions of MrUN10866, MrUN33504, MrUN37588, and MrUN40182 were induced by cold stress [95]. Numerous transcription factors (TFs) have been identified, and they all play crucial roles in how plants react to abiotic stressors, such as cold, including AP2/ERF, bHLH, MYB, WRKY, C2H2, and NAC. The AP2/ERF TF family, whose members have been extensively characterized for their involvement in cold tolerance, was the largest. This finding suggests these genes play a crucial role in the abiotic stress response, and they may be utilized in breeding alfalfa [146]. The wild Medicago species that presented tolerance in the above-mentioned abiotic stresses are presented in Table 1. 2.4. Woody Perennial Crops

Climate changes leading to temperature alterations (increased heat or cold), extreme weather phenomena (e.g., dry spells, heat waves, heavy rainfalls), and water availability (drought or flooding conditions) pose threats to the cultivation of woody perennial crops. Changes in weather patterns subsequently exacerbate biotic stresses and the spread of diseases. Ultimately, these adverse abiotic and biotic effects significantly compromise yield and quality of the final product. In recent years, numerous efforts have been undertaken to expand the genetic pool of woody perennial crops by exploiting the genetic diversity of wild relatives and introgressing new desirable climate-resilient traits into cultivated varieties

2.4. Woody Perennial Crops

Climate changes leading to temperature alterations (increased heat or cold), extreme weather phenomena (e.g., dry spells, heat waves, heavy rainfalls), and water availability (drought or flooding conditions) pose threats to the cultivation of woody perennial crops. Changes in weather patterns subsequently exacerbate biotic stresses and the spread of diseases. Ultimately, these adverse abiotic and biotic effects significantly compromise yield and quality of the final product. In recent years, numerous efforts have been undertaken to expand the genetic pool of woody perennial crops by exploiting the genetic diversity of wild relatives and introgressing new desirable climate-resilient traits into cultivated varieties

[148][149].


2.4.1. Apple

.

2.4.1. Apple

The cultivated apple, Malus domestica Borkh., is a diploid or triploid species with a haploid set of 17 chromosomes and a genome size of approximately 600 Mb [150]. Apple cultivation and production constitute one of the major fruit-producing industries addressing markets worldwide. However, climatic changes introduce a series of environmental stressors which challenge apple yield and fruit quality. Apple breeding could greatly benefit from apple wild relatives to face the challenge from adverse environmental conditions and biotic and abiotic stressors [149]. For example, wild relatives, Malus floribunda, Malus baccata, and Malus micromalus, have been used to pyramid apple scab and powdery mildew resistance genes into progeny [151]. Assessment of a broad range of wild Malus germplasm over the last 30 years has revealed ample potential sources of resistance to a multitude of diseases. Similarly, apple wild relatives in Malus collections have been evaluated and shown to possess traits related to fruit quality as well as abiotic stress resilience, such as cold hardiness and drought tolerance [44]. In addition, investigations on the molecular basis of stress tolerance have indicated a key role for a DREB2 (dehydration-responsive element-binding factor 2) homologue in response to drought, cold, and heat in two highly drought-tolerant wild apple relatives, Malus sieversii and Malus prunifolia [45][46]. Likewise, Diacylglycerol kinase (DGK) genes were found to exhibit marked upregulation in response to drought and salt stress in M. prunifolia [58]. Comparative analyses between two widely used apple rootstocks (M. sieversii and R3) under water deficit conditions demonstrated M. sieversii is more tolerant to drought. Transcriptomic analysis of root tissue showed differential expression of stress-responsive genes associated with oxidative stress, signaling pathways in hormone biosynthesis, and transcriptional regulation between the two genotypes, suggesting these genes play a crucial role in root processes that provide drought tolerance [152]. Moreover, the deciphering of the cold-tolerant wild apple Malus baccata genome identified cold-responsive genes (COR) that will be useful in marker-assisted selection in breeding programs [47]. Collectively, the Malus wild relatives provide an important genetic resource for incorporating resilience in cultivated apple varieties.

2.4.2. Cranberry

2.4.2. Cranberry

Research focusing on wild cranberry is another example of targeted use of genetic variation in perennial wild populations toward the benefit of breeding resilient varieties [48][153]. Cranberry (Vaccinium macrocarpon Ait.), a fruit crop of high economic value in North America, Northern Europe, and Asia, often encounters a series of abiotic and biotic challenges, such as frost damage, high temperatures, drought, flooding, and fungal diseases, which lead to severe production losses. Recently, a collection of many wild cranberry (Vaccinium macrocarpon Aiton) accessions from the northern U.S. and Canada was assessed through environmental association analysis and revealed genomic regions linked to potential abiotic stress tolerance. One hundred twenty-six significant associations between SNP marker loci (many of which tagged genes with functional annotations) and environmental variables of temperature, precipitation, and soil attributes were uncovered [154].

2.4.3. Grapevine

2.4.3. Grapevine

Although the Vitis genus is composed of 60 species, the species used predominately for grapevine cultivation is Vitis vinifera L. Nevertheless, wild Vitis relatives exhibit important traits not found in V. vinifera, such as resistance to the devastating ‘Pierce’s disease’ (PD) caused by the bacterium Xyllela fastidiosa. Breeding programs focused on a PD-resistant grapevine wild relative, Vitis arizonica, to generate PD-resistant lines. Over the years, using V. arizonica x V. vinifera crosses, repeated backcrosses with V. vinifera and marker assisted selection (MAS) techniques, breeders managed to develop breeding grapevine lines with PD resistance and 97% V. vinifera ancestry [155]. Similarly, to confront two major grapevine fungal diseases, downy mildew (Plasmopara viticola) and powdery mildew (Erysiphe necator), the wild relative Muscadinia rotundifolia was utilized. Crosses with Vitis vinifera and subsequent crosses with other Vitis hybrids resulted in progeny containing genes implicated in resistance to both powdery and downy mildew [156][157]. On the other hand, molecular studies have begun to elucidate the genetic basis of abiotic stress tolerance displayed by wild Vitis relatives. Overexpression of a stress-related gene from the Chinese wild grape Vitis yeshanensis encoding a universal stress protein, VyUSPA3, was shown to confer drought tolerance to transgenic V. vinifera cv. ‘Thompson Seedless’ [49]  (Table 1). In addition, comparative transcriptomic analysis performed between a coastline wild grapevine (Vitis vinifera L. ssp. sylvestris) accession which is tolerant to high-salinity levels and the commercial rootstock, Richter 110, a salt-sensitive cultivar, revealed differential gene expression profiles upon salinity stress [65] (Table 1). These findings facilitate the investigation of gene pathways that play key roles in survival under stress conditions and highlight the potential of such grapevine wild relatives as breeding material both for scion and rootstock improvement. In view of the gloomy projections of 56 to 73% loss of suitable land for viticulture in major wine-producing regions by 2050 [158][159], studies have been focusing on grapevine wild relatives with resilience to climate risk [160]. Recently, associations of wild species SNPs (single nucleotide polymorphisms) with bioclimatic variables and putative adaptation to biotic and abiotic stressors have been explored [173]. In addition, by integrating species distribution models, adaptive genetic variation, genomic load and phenotype, Aguirre-Liguori et al.  [161] predicted certain accessions of the wild grapevine species, Vitis mustangensis, are well-suited for future climates and can contribute to grapevine bioclimatic adaptation. Importantly, commercial rootstocks currently used globally for grapevine grafting were derived from North American wild Vitis species. These rootstocks have been used since the second half of the nineteenth century to save European grapevines from the plague of the soil-borne aphid, phylloxera (Daktulosphaira vitifoliae) [162]. Moreover, depending on the rootstock, they confer drought, cold tolerance, and disease resistance to grafted grapevine [163]. Likewise, rootstocks have been used widely for improving other cultivated woody perennials (apple, pear, peach, mango, citrus, etc.). However, in general, relatively few rootstock genotypes are employed in grafting of woody perennial crops. Wild relatives could serve as a significant allele pool for developing new rootstock varieties with advantageous traits that would impart the grafted plant with resilience to environmental stressors [148].

References

  1. Hichri, I.; Muhovski, Y.; Žižková, E.; Dobrev, P.I.; Gharbi, E.; Franco-Zorrilla, J.M.; Lopez-Vidriero, I.; Solano, R.; Clippe, A.; Errachid, A.; et al. The Solanum lycopersicum WRKY3 Transcription Factor SlWRKY3 Is Involved in Salt Stress Tolerance in Tomato. Front. Plant Sci. 2017, 8, 1343.
  2. Barone, A.; Chiusano, M.L.; Ercolano, M.R.; Giuliano, G.; Grandillo, S.; Frusciante, L. Structural and functional genomics of tomato. Int. J. Plant Genom. 2008, 2008, 820274.
  3. Bai, Y.; Kissoudis, C.; Yan, Z.; Visser, R.G.F.; van der Linden, G. Plant behaviour under combined stress: Tomato responses to combined salinity and pathogen stress. Plant J. 2018, 93, 781–793.
  4. Redden, R.; Yadav, S.S.; Maxted, N.; Dulloo, M.E.; Guarino, L.; Smith, P. Crop Wild Relatives and Climate Change; Wiley-Blackwell: Hoboken, NJ, USA, 2015.
  5. Ram, H.H. Vegetable Breeding: Principles and Practices; Kalyani Publishers: New Delhi, India, 2005.
  6. Rai, N.; Rai, M. Heterosis Breeding in Vegetable Crops; New India Publishing Agency: New Delhi, India, 2006.
  7. O’Connell, M.A.; Medina, A.L.; Sanchez, P.; Trevino, M. Molecular genetics of drought resistance response in tomato and related species. In Genetic Improvement of Solanaceous Crops, Volume 2: Tomato; Razdan, M.K., Mattoo, A.K., Eds.; Science Publishers: Enfield, CT, USA, 2007; pp. 261–283.
  8. Krishna, R.; Ansari, W.A.; Soumia, P.S.; Yadav, A.; Jaiswal, D.K.; Kumar, S.; Singh, A.K.; Singh, M.; Verma, J.P. Biotechnological Interventions in Tomato (Solanum lycopersicum) for Drought Stress Tolerance: Achievements and Future Prospects. BioTech 2022, 11, 48.
  9. Pailles, Y.; Awlia, M.; Julkowska, M.; Passone, L.; Zemmouri, K.; Negrão, S.; Schmöckel, S.M.; Tester, M. Diverse Traits Contribute to Salinity Tolerance of Wild Tomato Seedlings from the Galapagos Islands1 . Plant Physiol. 2019, 182, 534–546.
  10. Tiwari, S.K. Genetic Resources of Solanaceous Vegetables in India; Indian Institute of Vegetable Research: Jakkhini, India, 2011.
  11. Molitor, C.; Kurowski, T.J.; Fidalgo de Almeida, P.M.; Eerolla, P.; Spindlow, D.J.; Kashyap, S.P.; Singh, B.; Prasanna, H.C.; Thompson, A.J.; Mohareb, F.R. De novo genome assembly of Solanum sitiens reveals structural variation associated with drought and salinity tolerance. Bioinformatics 2021, 37, 1941–1945.
  12. Foolad, M.R.; Chen, F.Q.; Lin, G.Y. RFLP mapping of QTLs conferring salt tolerance during germination in an interspecific cross of tomato. Theor. Appl. Genet. 1998, 97, 1133–1144.
  13. Foolad, M.R.; Jones, R.A. Mapping salt-tolerance genes in tomato (Lycopersicon esculentum) using trait-based marker analysis. Theor. Appl. Genet. 1993, 87, 184–192.
  14. Frary, A.; Göl, D.; Keleş, D.; Ökmen, B.; Pınar, H.; Şığva, H.Ö.; Yemenicioğlu, A.; Doğanlar, S. Salt tolerance in Solanum pennellii: Antioxidant response and related QTL. BMC Plant Biol. 2010, 10, 58.
  15. Rao, E.S.; Kadirvel, P.; Symonds, R.C.; Geethanjali, S.; Thontadarya, R.N.; Ebert, A.W. Variations in DREB1A and VP1.1 Genes Show Association with Salt Tolerance Traits in Wild Tomato (Solanum pimpinellifolium). PLoS ONE 2015, 10, e0132535.
  16. Gonzalo, M.J.; Nájera, I.; Baixauli, C.; Gil, D.; Montoro, T.; Soriano, V.; Olivieri, F.; Rigano, M.M.; Ganeva, D.; Grozeva-Tileva, S.; et al. Identification of tomato accessions as source of new genes for improving heat tolerance: From controlled experiments to field. BMC Plant Biol. 2021, 21, 345.
  17. Golam, F.; Prodhan, Z.H.; Nezhadahmadi, A.; Rahman, M. Heat Tolerance in Tomato. Life Sci. J. 2012, 99, 1936–1950.
  18. Nahar, K. Effect of Water Stress on Moisture Content Distribution in Soil and Morphological Characters of Two Tomato (Lycopersicon esculentum Mill) Cultivars. J. Sci. Res. 2011, 3, 677–682.
  19. Young, N.D.; Debellé, F.; Oldroyd, G.E.D.; Geurts, R.; Cannon, S.B.; Udvardi, M.K.; Benedito, V.A.; Mayer, K.F.X.; Gouzy, J.; Schoof, H.; et al. The Medicago genome provides insight into the evolution of rhizobial symbioses. Nature 2011, 480, 520–524.
  20. Yin, M.; Zhang, S.; Du, X.; Mateo, R.G.; Guo, W.; Li, A.; Wang, Z.; Wu, S.; Chen, J.; Liu, J.; et al. Genomic analysis of Medicago ruthenica provides insights into its tolerance to abiotic stress and demographic history. Mol. Ecol. Resour. 2021, 21, 1641–1657.
  21. Wang, T.; Ren, L.; Li, C.; Zhang, D.; Zhang, X.; Zhou, G.; Gao, D.; Chen, R.; Chen, Y.; Wang, Z.; et al. The genome of a wild Medicago species provides insights into the tolerant mechanisms of legume forage to environmental stress. BMC Biol. 2021, 19, 96.
  22. Cui, J.; Lu, Z.; Wang, T.; Chen, G.; Mostafa, S.; Ren, H.; Liu, S.; Fu, C.; Wang, L.; Zhu, Y.; et al. The genome of Medicago polymorpha provides insights into its edibility and nutritional value as a vegetable and forage legume. Hortic. Res. 2021, 8, 47.
  23. Jenczewski, E.; Prosperi, J.M.; Ronfort, J. Evidence for gene flow between wild and cultivated Medicago sativa (Leguminosae) based on allozyme markers andquantitative traits. Am. J. Bot. 1999, 86, 677–687.
  24. Naito, K.; Wakatake, T.; Shibata, T.F.; Iseki, K.; Shigenobu, S.; Takahashi, Y.; Ogiso-Tanaka, E.; Muto, C.; Teruya, K.; Shiroma, A.; et al. Genome sequence of 12 Vigna species as a knowledge base of stress tolerance and resistance. tommoka 2022.
  25. Van Zonneveld, M.; Rakha, M.; Tan, S.Y.; Chou, Y.Y.; Chang, C.H.; Yen, J.Y.; Schafleitner, R.; Nair, R.; Naito, K.; Solberg, S. Mapping patterns of abiotic and biotic stress resilience uncovers conservation gaps and breeding potential of Vigna wild relatives. Sci. Rep. 2020, 10, 2111.
  26. Chankaew, S.; Isemura, T.; Naito, K.; Ogiso-Tanaka, E.; Tomooka, N.; Somta, P.; Kaga, A.; Vaughan, D.A.; Srinives, P. QTL mapping for salt tolerance and domestication-related traits in Vigna marina subsp. oblonga, a halophytic species. Theor. Appl. Genet. 2014, 127, 691–702.
  27. Sanjeewani, B.L.G.; Jayasuriya, K.M.G.G.; Kirthisinghe, J.P. Effect of salinity on seed germination of Vigna marina a wild relative of crop Vigna species using hydrotime modelling. In Proceedings of the 17th International Forestry and Environment Symposium, University of Sri Jayewardenepura, Nugegoda, Sri Lanka, 16–17 November 2012.
  28. Yoshida, Y.; Marubodee, R.; Ogiso-Tanaka, E.; Iseki, K.; Isemura, T.; Takahashi, Y.; Muto, C.; Naito, K.; Kaga, A.; Okuno, K.; et al. Salt tolerance in wild relatives of adzuki bean, Vigna angularis (Willd.) Ohwi et Ohashi. Genet. Resour. Crop Evol. 2016, 63, 627–637.
  29. Iseki, K.; Takahashi, Y.; Muto, C.; Naito, K.; Tomooka, N. Diversity and Evolution of Salt Tolerance in the Genus Vigna. PLoS ONE 2016, 11, e0164711.
  30. Tomooka, N.; Naito, K.; Kaga, A.; Sakai, H.; Isemura, T.; Ogiso-Tanaka, E.; Iseki, K.; Takahashi, Y. Evolution, domestication and neo-domestication of the genus Vigna. Plant Genet. Resour. 2014, 12, S168–S171.
  31. Takahashi, Y.; Somta, P.; Muto, C.; Iseki, K.; Naito, K.; Pandiyan, M.; Natesan, S.; Tomooka, N. Novel Genetic Resources in the Genus Vigna Unveiled from Gene Bank Accessions. PLoS ONE 2016, 11, e0147568.
  32. Miller, I.; Williams, W.J.T.G. Tolerance of some tropical legumes to six months of simulated waterlogging. Trop. Grassl. 1981, 15, 39–43.
  33. Cason, J.M. Introgression Pathway for Drought Tolerance in Peanut (Arachis hypogea L.). Ph.D. Thesis, Texas A & M University, College Station, TX, USA, 2018.
  34. Rampuria, S.; Bag, P.; Rogan, C.J.; Sharma, A.; Gassmann, W.; Kirti, P.B. Pathogen-induced AdDjSKI of the wild peanut, Arachis diogoi, potentiates tolerance of multiple stresses in E. coli and tobacco. Plant Sci. Int. J. Exp. Plant Biol. 2018, 272, 62–74.
  35. Vinson, C.C.; Mota, A.P.Z.; Oliveira, T.N.; Guimaraes, L.A.; Leal-Bertioli, S.C.M.; Williams, T.C.R.; Nepomuceno, A.L.; Saraiva, M.A.P.; Araujo, A.C.G.; Guimaraes, P.M.; et al. Early responses to dehydration in contrasting wild Arachis species. PLoS ONE 2018, 13, e0198191.
  36. Song, X.; Li, E.; Song, H.; Du, G.; Li, S.; Zhu, H.; Chen, G.; Zhao, C.; Qiao, L.; Wang, J.; et al. Genome-wide identification and characterization of nonspecific lipid transfer protein (nsLTP) genes in Arachis duranensis. Genomics 2020, 112, 4332–4341.
  37. Zhao, C.; He, L.; Xia, H.; Zhou, X.; Geng, Y.; Hou, L.; Li, P.; Li, G.; Zhao, S.; Ma, C.; et al. De novo full length transcriptome analysis of Arachis glabrata provides insights into gene expression dynamics in response to biotic and abiotic stresses. Genomics 2021, 113, 1579–1588.
  38. Brasileiro, A.C.; Morgante, C.V.; Araujo, A.C.; Leal-Bertioli, S.C.; Silva, A.K.; Martins, A.C.; Vinson, C.C.; Santos, C.M.; Bonfim, O.; Togawa, R.C.; et al. Transcriptome Profiling of Wild Arachis from Water-Limited Environments Uncovers Drought Tolerance Candidate Genes. Plant Mol. Biol. Rep. 2015, 33, 1876–1892.
  39. Wang, P.; Song, H.; Li, C.; Li, P.; Li, A.; Guan, H.; Hou, L.; Wang, X. Genome-wide dissection of the heat shock transcription factor family genes in Arachis. Front. Plant Sci. 2017, 8, 106.
  40. Nautiyal, P.C.; Rajgopal, K.; Zala, P.V.; Pujari, D.S.; Basu, M.; Dhadhal, B.A.; Nandre, B.M. Evaluation of wild Arachis species for abiotic stress tolerance: I. Thermal stress and leaf water relations. Euphytica 2008, 159, 43–57.
  41. Yuan, C.; Li, C.; Lu, X.; Zhao, X.; Yan, C.; Wang, J.; Sun, Q.; Shan, S. Comprehensive genomic characterization of NAC transcription factor family and their response to salt and drought stress in peanut. BMC Plant Biol. 2020, 20, 454.
  42. Martins, A.C.Q.; Mota, A.P.Z.; Carvalho, P.; Passos, M.A.S.; Gimenes, M.A.; Guimaraes, P.M.; Brasileiro, A.C.M. Transcriptome Responses of Wild Arachis to UV-C Exposure Reveal Genes Involved in General Plant Defense and Priming. Plants 2022, 11, 408.
  43. Li, Y.; Tan, Y.; Shao, Y.; Li, M.; Ma, F. Comprehensive genomic analysis and expression profiling of diacylglycerol kinase gene family in Malus prunifolia (Willd.) Borkh. Gene 2015, 561, 225–234.
  44. Volk, G.M.; Chao, C.T.; Norelli, J.; Brown, S.K.; Fazio, G.; Peace, C.; McFerson, J.; Zhong, G.-Y.; Bretting, P. The vulnerability of US apple (Malus) genetic resources. Genet. Resour. Crop Evol. 2015, 62, 765–794.
  45. Zhao, K.; Shen, X.; Yuan, H.; Liu, Y.; Liao, X.; Wang, Q.; Liu, L.; Li, F.; Li, T. Isolation and characterization of dehydration-responsive element-binding factor 2C (MsDREB2C) from Malus sieversii Roem. Plant Cell Physiol. 2013, 54, 1415–1430.
  46. Zhao, T.; Liang, D.; Wang, P.; Liu, J.; Ma, F. Genome-wide analysis and expression profiling of the DREB transcription factor gene family in Malus under abiotic stress. Mol. Genet. Genom. 2012, 287, 423–436.
  47. Chen, X.; Li, S.; Zhang, D.; Han, M.; Jin, X.; Zhao, C.; Wang, S.; Xing, L.; Ma, J.; Ji, J.; et al. Sequencing of a Wild Apple (Malus baccata) Genome Unravels the Differences Between Cultivated and Wild Apple Species Regarding Disease Resistance and Cold Tolerance. G3 Genes Genomes Genet. 2019, 9, 2051–2060.
  48. Kawash, J.; Colt, K.; Hartwick, N.T.; Abramson, B.W.; Vorsa, N.; Polashock, J.J.; Michael, T.P. Contrasting a reference cranberry genome to a crop wild relative provides insights into adaptation, domestication, and breeding. PLoS ONE 2022, 17, e0264966.
  49. Cui, X.; Zhang, P.; Chen, C.; Zhang, J. VyUSPA3, a universal stress protein from the Chinese wild grape Vitis yeshanensis, confers drought tolerance to transgenic V. vinifera. Plant Cell Rep. 2022.
  50. Carrasco, D.; Zhou-Tsang, A.; Rodriguez-Izquierdo, A.; Ocete, R.; Revilla, M.A.; Arroyo-García, R. Coastal Wild Grapevine Accession (Vitis vinifera L. ssp. sylvestris) Shows Distinct Late and Early Transcriptome Changes under Salt Stress in Comparison to Commercial Rootstock Richter 110. Plants 2022, 11, 2688.
  51. Fischer, I.; Steige, K.A.; Stephan, W.; Mboup, M. Sequence Evolution and Expression Regulation of Stress-Responsive Genes in Natural Populations of Wild Tomato. PLoS ONE 2013, 8, e78182.
  52. Zhang, H.; Mittal, N.; Leamy, L.J.; Barazani, O.; Song, B.-H. Back into the wild—Apply untapped genetic diversity of wild relatives for crop improvement. Evol. Appl. 2017, 10, 5–24.
  53. Eshed, Y.; Zamir, D. An introgression line population of Lycopersicon pennellii in the cultivated tomato enables the identification and fine mapping of yield-associated QTL. Genetics 1995, 141, 1147–1162.
  54. Sellitto, S.; Chiaiese, P.; Rigano, M.; Barone, A.; Frusciante, L.; Di Matteo, A. Dissecting drought tolerance in a tomato introgression line. In Proceedings of the 57th Italian Society of Agricultural Genetics Annual Congress, Foggia, Italy, 16–19 September 2013. Poster Communication Abstract—8.22.
  55. Solankey, S.S.; Singh, R.; Baranwal, D.; Singh, D.K. Genetic Expression of Tomato for Heat and Drought Stress Tolerance: An Overview. Int. J. Veg. Sci. 2015, 21, 496–515.
  56. Razali, R.; Bougouffa, S.; Morton, M.J.L.; Lightfoot, D.J.; Alam, I.; Essack, M.; Arold, S.T.; Kamau, A.A.; Schmöckel, S.M.; Pailles, Y.; et al. The Genome Sequence of the Wild Tomato Solanum pimpinellifolium Provides Insights Into Salinity Tolerance. Front. Plant Sci. 2018, 9, 1402.
  57. Böndel, K.B.; Nosenko, T.; Stephan, W. Signatures of natural selection in abiotic stress-responsive genes of Solanum chilense. R. Soc. Open Sci. 2018, 5, 171198.
  58. Salinas-Cornejo, J.; Madrid-Espinoza, J.; Ruiz-Lara, S. Identification and transcriptional analysis of SNARE vesicle fusion regulators in tomato (Solanum lycopersicum) during plant development and a comparative analysis of the response to salt stress with wild relatives. J. Plant Physiol. 2019, 242, 153018.
  59. Foolad, M.R.; Subbiah, P.; Zhang, L. Common QTL affect the rate of tomato seed germination under different stress and nonstress conditions. Int. J. Plant Genom. 2007, 2007, 97386.
  60. Bretó, M.P.; Aśins, M.J.; Carbonell, E.A. Salt tolerance in Lycopersicon species. III. Detection of quantitative trait loci by means of molecular markers. Theor. Appl. Genet. Theor. Angew. Genet. 1994, 88, 395–401.
  61. Foolad, M.R.; Lin, G.Y.; Chen, F.Q. Comparison of QTLs for seed germination under non-stress, cold stress and salt stress in tomato. Plant Breed. 1999, 118, 167–173.
  62. Kashyap, S.P.; Kumari, N.; Mishra, P.; Moharana, D.P.; Aamir, M. Tapping the potential of Solanum lycopersicum L. pertaining to salinity tolerance: Perspectives and challenges. Genet. Resour. Crop Evol. 2021, 68, 2207–2233.
  63. Chaudhry, S.; Sidhu, G.P.S. Climate change regulated abiotic stress mechanisms in plants: A comprehensive review. Plant Cell Rep. 2022, 41, 1–31.
  64. Hasanuzzaman, M.; Nahar, K.; Alam, M.M.; Roychowdhury, R.; Fujita, M. Physiological, biochemical, and molecular mechanisms of heat stress tolerance in plants. Int. J. Mol. Sci. 2013, 14, 9643–9684.
  65. Ungelenk, S.; Moayed, F.; Ho, C.-T.; Grousl, T.; Scharf, A.; Mashaghi, A.; Tans, S.; Mayer, M.P.; Mogk, A.; Bukau, B. Small heat shock proteins sequester misfolding proteins in near-native conformation for cellular protection and efficient refolding. Nat. Commun. 2016, 7, 13673.
  66. Wang, W.; Vinocur, B.; Altman, A. Plant responses to drought, salinity and extreme temperatures: Towards genetic engineering for stress tolerance. Planta 2003, 218, 1–14.
  67. Wang, L.; Zhao, C.M.; Wang, Y.J.; Liu, J. Overexpression of chloroplast-localized small molecular heat-shock protein enhances chilling tolerance in tomato plant. Zhi Wu Sheng Li Yu Fen Zi Sheng Wu Xue Xue Bao J. Plant Physiol. Mol. Biol. 2005, 31, 167–174.
  68. Elkelish, A.; Qari, S.H.; Mazrou, Y.S.A.; Abdelaal, K.A.A.; Hafez, Y.M.; Abu-Elsaoud, A.M.; Batiha, G.E.; El-Esawi, M.A.; El Nahhas, N. Exogenous Ascorbic Acid Induced Chilling Tolerance in Tomato Plants Through Modulating Metabolism, Osmolytes, Antioxidants, and Transcriptional Regulation of Catalase and Heat Shock Proteins. Plants 2020, 9, 431.
  69. Anjum, S.A.; Tanveer, M.; Hussain, S.; Bao, M.; Wang, L.; Khan, I.; Ullah, E.; Tung, S.A.; Samad, R.A.; Shahzad, B. Cadmium toxicity in Maize (Zea mays L.): Consequences on antioxidative systems, reactive oxygen species and cadmium accumulation. Environ. Sci. Pollut. Res. Int. 2015, 22, 17022–17030.
  70. Araújo, S.S.; Beebe, S.; Crespi, M.; Delbreil, B.; González, E.M.; Gruber, V.; Lejeune-Henaut, I.; Link, W.; Monteros, M.J.; Prats, E.; et al. Abiotic Stress Responses in Legumes: Strategies Used to Cope with Environmental Challenges. Crit. Rev. Plant Sci. 2015, 34, 237–280.
  71. Renzi, J.P.; Coyne, C.J.; Berger, J.; von Wettberg, E.; Nelson, M.; Ureta, S.; Hernández, F.; Smýkal, P.; Brus, J. How Could the Use of Crop Wild Relatives in Breeding Increase the Adaptation of Crops to Marginal Environments? Front. Plant Sci. 2022, 13, 886162.
  72. Stagnari, F.; Maggio, A.; Galieni, A.; Pisante, M. Multiple benefits of legumes for agriculture sustainability: An overview. Chem. Biol. Technol. Agric. 2017, 4, 2.
  73. Coulibaly, S.; Pasquet, R.S.; Papa, R.; Gepts, P. AFLP analysis of the phenetic organization and genetic diversity of Vigna unguiculata L. Walp. reveals extensive gene flow between wild and domesticated types. Theor. Appl. Genet. 2002, 104, 358–366.
  74. Herniter, I.A.; Muñoz-Amatriaín, M.; Close, T.J. Genetic, textual, and archeological evidence of the historical global spread of cowpea (Vigna unguiculata Walp.). Legume Sci. 2020, 2, e57.
  75. Huynh, B.-L.; Close, T.J.; Roberts, P.A.; Hu, Z.; Wanamaker, S.; Lucas, M.R.; Chiulele, R.; Cissé, N.; David, A.; Hearne, S.; et al. Gene Pools and the Genetic Architecture of Domesticated Cowpea. Plant Genome 2013, 6, plantgenome2013.03.0005.
  76. Vaillancourt, R.E.; Weeden, N.F. Chloroplast DNA polymorphism suggest Nigerian center of domestication for the cowpea Vigna unguiculata (Leguminosae). Am. J. Bot. 1992, 79, 1194–1199.
  77. Pratap, A.; Kumar, J. Alien Gene Transfer in Crop Plants: An Introduction. In Alien Gene Transfer in Crop Plants; Springer: New York, NY, USA, 2014; Volume 1.
  78. Maréchal, R.; Mascherpa, J.M.; Stainier, F. Extude taxonomique d’un groupe d’espèces des genres Phaseolus et Vigna (V. unguiculata) sur la base de données morphologiques et polliniques, traitées pour l’analyse informatique. Boissiera 1978, 28, 160–272.
  79. Lonardi, S.; Muñoz-Amatriaín, M.; Liang, Q.; Shu, S.; Wanamaker, S.I.; Lo, S.; Tanskanen, J.; Schulman, A.H.; Zhu, T.; Luo, M.C.; et al. The genome of cowpea (Vigna unguiculata Walp.). Plant J. Cell Mol. Biol. 2019, 98, 767–782.
  80. Xia, Q.; Pan, L.; Zhang, R.; Ni, X.; Wang, Y.; Dong, X.; Gao, Y.; Zhang, Z.; Kui, L.; Li, Y.; et al. The genome assembly of asparagus bean, Vigna unguiculata ssp. sesquipedialis. Sci. Data 2019, 6, 124.
  81. Srivastava, R.; Kobayashi, Y.; Koyama, H.; Sahoo, L. Cowpea NAC1/NAC2 transcription factors improve growth and tolerance to drought and heat in transgenic cowpea through combined activation of photosynthetic and antioxidant mechanisms. J. Integr. Plant Biol. 2022.
  82. Matos, M.; Benko-Iseppon, A.M.; Bezerra-Neto, J.P.; Ferreira-Neto, J.R.C.; Wang, Y.; Liu, H.; Pandolfi, V.; Amorim, L.L.B.; Willadino, L.; do Vale Amorim, T.C.; et al. The WRKY transcription factor family in cowpea: Genomic characterization and transcriptomic profiling under root dehydration. Gene 2022, 823, 146377.
  83. Sadhukhan, A.; Kobayashi, Y.; Kobayashi, Y.; Tokizawa, M.; Yamamoto, Y.Y.; Iuchi, S.; Koyama, H.; Panda, S.K.; Sahoo, L. VuDREB2A, a novel DREB2-type transcription factor in the drought-tolerant legume cowpea, mediates DRE-dependent expression of stress-responsive genes and confers enhanced drought resistance in transgenic Arabidopsis. Planta 2014, 240, 645–664.
  84. Garantizado, F.E.A.; Costa, J.H.; Maia, I.G.; Melo, M.D.F. Expressão diferencial dos genes VuUCP1a e VuUCP1b em caupi sob estresse salino. Rev. Ciência Agronômica 2011, 42, 404–408.
  85. Costa, J.H.; Mota, E.F.; Cambursano, M.V.; Lauxmann, M.A.; de Oliveira, L.M.; Silva Lima Mda, G.; Orellano, E.G.; Fernandes de Melo, D. Stress-induced co-expression of two alternative oxidase (VuAox1 and 2b) genes in Vigna unguiculata. J. Plant Physiol. 2010, 167, 561–570.
  86. Simoes-Araujo, J.L.; Alves-Ferreira, M.; Rumjanek, N.G.; Margis-Pinheiro, M. VuNIP1 (NOD26-like) and VuHSP17.7 gene expression are regulated in response to heat stress in cowpea nodule. Environ. Exp. Bot. 2008, 63, 256–265.
  87. Selinga, T.I.; Maseko, S.T.; Gabier, H.; Rafudeen, M.S.; Muasya, A.M.; Crespo, O.; Ogola, J.B.O.; Valentine, A.J.; Ottosen, C.-O.; Rosenqvist, E.; et al. Regulation and physiological function of proteins for heat tolerance in cowpea (Vigna unguiculata) genotypes under controlled and field conditions. Front. Plant Sci. 2022, 13, 954527.
  88. Gazendam, I. Identification and functional evaluation of a drought-induced “late embryogenesis abundant” gene from cowpea plants. Ph.D. Thesis, Faculty of Natural and Agricultural Sciences Department of Plant Science, University of Pretoria, Pretoria, South Africa, 2012.
  89. Iseki, K.; Takahashi, Y.; Muto, C.; Naito, K.; Tomooka, N. Diversity of Drought Tolerance in the Genus Vigna. Front. Plant Sci. 2018, 9, 729.
  90. Tomooka, N.; Kaga, A.; Isemura, T.; Vaughan, D.; Srinives, P.; Somta, P.; Thadavong, S.; Bounphanousay, C.; Kanyavong, K.; Inthapanya, P.; et al. Vigna Genetic Resources. In Proceedings of the 14th NIAS International Workshop on Genetic Resources—Genetic Resources and Comparative Genomics of Legumes (Glycine and Vigna), Tsukuba, Japan, 18 October 2011; National Institute of Agrobiological Science: Tsukuba, Japan, 2011.
  91. Yoshida, J.; Tomooka, N.; Yee Khaing, T.; Shantha, P.G.S.; Naito, H.; Matsuda, Y.; Ehara, H. Unique responses of three highly salt-tolerant wild Vigna species against salt stress. Plant Prod. Sci. 2020, 23, 114–128.
  92. Iseki, K.; Marubodee, R.; Ehara, H.; Tomooka, N. A rapid quantification method for tissue Na+ and K+ concentrations in salt-tolerant and susceptible accessions in Vigna vexillata (L.) A. Rich. Plant Prod. Sci. 2017, 20, 144–148.
  93. Garba, M.; Pasquet, R. The Vigna vexillata (L.) A. Rich. gene pool. In Proceedings of the Tuberous Legumes: International Symposium, Copenhagen, Denmark, 5–8 August 1996; pp. 61–71.
  94. Padulosi, S.; Ng, N.Q. Origin, taxonomy and morphology of Vigna unguiculata (L.) Walp. In Advances in Cowpea Research; Singh, B.B., Mohan Raji, D.R., Dashiel, K.E., Eds.; IITA: Ibadan, Nigeria, 1997.
  95. Barone, A.; Del Giudice, A.; Ng, N.Q. Barriers to interspecific hybridization between Vigna unguiculata and Vigna vexillata. Sex. Plant Reprod. 1992, 5, 195–200.
  96. Gomathinayagam, P.; Ganesh ram, S.; Rathnaswamy, R.; Ramaswamy, N.M. Interspecific hybridization between Vigna unguiculata (L.) Walp. and V. vexillata (L.) A. Rich. through in vitro embryo culture. Euphytica 1998, 102, 203–209.
  97. Abady, S.; Shimelis, H.; Janila, P.; Yaduru, S.; Shayanowako, A.I.T.; Deshmukh, D.; Chaudhari, S.; Manohar, S.S. Assessment of the genetic diversity and population structure of groundnut germplasm collections using phenotypic traits and SNP markers: Implications for drought tolerance breeding. PLoS ONE 2021, 16, e0259883.
  98. Harouna, D.V.; Venkataramana, P.B.; Matemu, A.O.; Ndakidemi, P.A. Agro-Morphological Exploration of Some Unexplored Wild Vigna Legumes for Domestication. Agronomy 2020, 10, 111.
  99. Amorim, L.L.B.; Ferreira-Neto, J.R.C.; Bezerra-Neto, J.P.; Pandolfi, V.; de Araújo, F.T.; da Silva Matos, M.K.; Santos, M.G.; Kido, E.A.; Benko-Iseppon, A.M. Cowpea and abiotic stresses: Identification of reference genes for transcriptional profiling by qPCR. Plant Methods 2018, 14, 88.
  100. Pasupuleti, J.; Nigam, S.N.; Pandey, M.K.; Nagesh, P.; Varshney, R. Groundnut improvement: Use of genetic and genomic tools. Front. Plant Sci. 2013, 4, 23.
  101. Bertioli, D.J.; Cannon, S.B.; Froenicke, L.; Huang, G.; Farmer, A.D.; Cannon, E.K.S.; Liu, X.; Gao, D.; Clevenger, J.; Dash, S.; et al. The genome sequences of Arachis duranensis and Arachis ipaensis, the diploid ancestors of cultivated peanut. Nat. Genet. 2016, 48, 438–446.
  102. Samoluk, S.S.; Robledo, G.; Podio, M.; Chalup, L.; Ortiz, J.P.; Pessino, S.C.; Seijo, J.G. First insight into divergence, representation and chromosome distribution of reverse transcriptase fragments from L1 retrotransposons in peanut and wild relative species. Genetica 2015, 143, 113–125.
  103. Bertioli, D.J.; Seijo, G.; Freitas, F.O.; Valls, J.F.M.; Leal-Bertioli, S.C.M.; Moretzsohn, M.C. An overview of peanut and its wild relatives. Plant Genet. Resour. 2011, 9, 134–149.
  104. Stalker, H.T. Utilizing Wild Species for Peanut Improvement. Crop Sci. 2017, 57, 1102–1120.
  105. Kokkanti, R.; Hindu, V.; Latha, P.; Vasanthi, R.P.; Sudhakar, P.; Usha, R. Assessment of genetic variability and molecular characterization of heat stress tolerant genes in Arachis hypogaea L. through qRT-PCR. Biocatal. Agric. Biotechnol. 2019, 20, 101242.
  106. Agarwal, M.; Hao, Y.; Kapoor, A.; Dong, C.H.; Fujii, H.; Zheng, X.; Zhu, J.K. A R2R3 type MYB transcription factor is involved in the cold regulation of CBF genes and in acquired freezing tolerance. J. Biol. Chem. 2006, 281, 37636–37645.
  107. Agarwal, P.K.; Gupta, K.; Lopato, S.; Agarwal, P. Dehydration responsive element binding transcription factors and their applications for the engineering of stress tolerance. J. Exp. Bot. 2017, 68, 2135–2148.
  108. Akhtar, M.; Jaiswal, A.; Taj, G.; Jaiswal, J.P.; Qureshi, M.I.; Singh, N.K. DREB1/CBF transcription factors: Their structure, function and role in abiotic stress tolerance in plants. J. Genet. 2012, 91, 385–395.
  109. Mizoi, J.; Shinozaki, K.; Yamaguchi-Shinozaki, K. AP2/ERF family transcription factors in plant abiotic stress responses. Biochim. Et Biophys. Acta (BBA)—Gene Regul. Mech. 2012, 1819, 86–96.
  110. Bhatnagar-Mathur, P.; Devi, M.J.; Reddy, D.S.; Lavanya, M.; Vadez, V.; Serraj, R.; Yamaguchi-Shinozaki, K.; Sharma, K.K. Stress-inducible expression of At DREB1A in transgenic peanut (Arachis hypogaea L.) increases transpiration efficiency under water-limiting conditions. Plant Cell Rep. 2007, 26, 2071–2082.
  111. Bhatnagar-Mathur, P.; Rao, J.S.; Vadez, V.; Dumbala, S.R.; Rathore, A.; Yamaguchi-Shinozaki, K.; Sharma, K.K. Transgenic peanut overexpressing the DREB1A transcription factor has higher yields under drought stress. Mol. Breed. 2014, 33, 327–340.
  112. Sarkar, T.; Thankappan, R.; Kumar, A.; Mishra, G.P.; Dobaria, J.R. Stress Inducible Expression of AtDREB1A Transcription Factor in Transgenic Peanut (Arachis hypogaea L.) Conferred Tolerance to Soil-Moisture Deficit Stress. Front. Plant Sci. 2016, 7, 935.
  113. Zhang, M.; Liu, W.; Bi, Y.; Wang, Z. Isolation and Identification of pndreb1-A New DREB Transcription Factor from Peanut (Arachis hypogaea L.). Acta Agron. Sin. 2009, 35, 1973–1980.
  114. Li, X.; Lu, J.; Liu, S.; Liu, X.; Lin, Y.; Li, L. Identification of rapidly induced genes in the response of peanut (Arachis hypogaea) to water deficit and abscisic acid. BMC Biotechnol. 2014, 14, 58.
  115. Wan, L.; Wu, Y.; Huang, J.; Dai, X.; Lei, Y.; Yan, L.; Jiang, H.; Zhang, J.; Varshney, R.K.; Liao, B. Identification of ERF genes in peanuts and functional analysis of AhERF008 and AhERF019 in abiotic stress response. Funct. Integr. Genom. 2014, 14, 467–477.
  116. Wan, L.; Zhang, J.; Zhang, H.; Zhang, Z.; Quan, R.; Zhou, S.; Huang, R. Transcriptional Activation of OsDERF1 in OsERF3 and OsAP2-39 Negatively Modulates Ethylene Synthesis and Drought Tolerance in Rice. PLoS ONE 2011, 6, e25216.
  117. Qiao, L.; Jiang, P.; Tang, Y.; Pan, L.; Ji, H.; Zhou, W.; Zhu, H.; Sui, J.; Jiang, D.; Wang, J. Characterization of AhLea-3 and its enhancement of salt tolerance in transgenic peanut plants. Electron. J. Biotechnol. 2021, 49, 42–49.
  118. Sottosanto, J.B.; Saranga, Y.; Blumwald, E. Impact of AtNHX1, a vacuolar Na+/H+ antiporter, upon gene expression during short- and long-term salt stress in Arabidopsis thaliana. BMC Plant Biol. 2007, 7, 18.
  119. Asif, M.A.; Zafar, Y.; Iqbal, J.; Iqbal, M.M.; Rashid, U.; Ali, G.M.; Arif, A.; Nazir, F. Enhanced Expression of AtNHX1, in Transgenic Groundnut (Arachis hypogaea L.) Improves Salt and Drought Tolerance. Mol. Biotechnol. 2011, 49, 250–256.
  120. Banavath, J.N.; Chakradhar, T.; Pandit, V.; Konduru, S.; Guduru, K.K.; Akila, C.S.; Podha, S.; Puli, C.O.R. Stress Inducible Overexpression of AtHDG11 Leads to Improved Drought and Salt Stress Tolerance in Peanut (Arachis hypogaea L.). Front. Chem. 2018, 6, 34.
  121. Cason, J.M.; Simpson, C.E.; Rooney, W.L.; Brady, J.A. Drought-tolerant transcription factors identified in Arachis dardani and Arachis ipaënsis. Agrosyst. Geosci. Environ. 2020, 3, e20069.
  122. Guimarães, P.M.; Brasileiro, A.C.M.; Morgante, C.V.; Martins, A.C.Q.; Pappas, G.; Silva, O.B.; Togawa, R.; Leal-Bertioli, S.C.M.; Araujo, A.C.G.; Moretzsohn, M.C.; et al. Global transcriptome analysis of two wild relatives of peanut under drought and fungi infection. BMC Genom. 2012, 13, 387.
  123. Mota, A.P.Z.; Brasileiro, A.C.M.; Vidigal, B.; Oliveira, T.N.; da Cunha Quintana Martins, A.; Saraiva, M.A.d.P.; de Araújo, A.C.G.; Togawa, R.C.; Grossi-de-Sá, M.F.; Guimaraes, P.M. Defining the combined stress response in wild Arachis. Sci. Rep. 2021, 11, 11097.
  124. Gai, W.; Sun, H.; Hu, Y.; Liu, C.; Zhang, Y.; Gai, S.; Yuan, Y. Genome-Wide Identification of Membrane-Bound Fatty Acid Desaturase Genes in Three Peanut Species and Their Expression in Arachis hypogaea during Drought Stress. Genes 2022, 13, 1718.
  125. Li, L.; Hu, B.; Li, X.; Li, L. Characterization of mTERF family in allotetraploid peanut and their expression levels in response to dehydration stress. Biotechnol. Biotechnol. Equip. 2020, 34, 1176–1187.
  126. Sharma, S. Prebreeding Using Wild Species for Genetic Enhancement of Grain Legumes at ICRISAT. Crop Sci. 2017, 57, 1132–1144.
  127. Gowda, M.; Motagi, B.; Naidu, G.K.; Diddimani, S.B.; Sheshagiri, R. GPBD 4: A Spanish bunch Groundnut Genotype Resistant to Rust and Late leaf spot. Int. Arachis Newsl. 2002, 22, 29–32.
  128. Khedikar, Y.P.; Gowda, M.V.; Sarvamangala, C.; Patgar, K.V.; Upadhyaya, H.D.; Varshney, R.K. A QTL study on late leaf spot and rust revealed one major QTL for molecular breeding for rust resistance in groundnut (Arachis hypogaea L.). Theor. Appl. Genet. Theor. Angew. Genet. 2010, 121, 971–984.
  129. Leal-Bertioli, S.C.M.; Bertioli, D.J.; Guimarães, P.M.; Pereira, T.D.; Galhardo, I.; Silva, J.P.; Brasileiro, A.C.M.; Oliveira, R.S.; Silva, P.Í.T.; Vadez, V.; et al. The effect of tetraploidization of wild Arachis on leaf morphology and other drought-related traits. Environ. Exp. Bot. 2012, 84, 17–24.
  130. Simpson, C.E.; Nelson, S.C.; Starr, J.L.; Woodard, K.E.; Smith, O.D. Registration of TxAG-6 and TxAG-7 Peanut Germplasm Lines. Crop Sci. 1993, 33.
  131. Stalker, H.T. Utilizing Arachis cardenasii as a source of Cercospora leafspot resistance for peanut improvement. Euphytica 1984, 33, 529–538.
  132. Kumari, V.; Gowda, M.V.C.; Tasiwal, V.; Pandey, M.K.; Bhat, R.S.; Mallikarjuna, N.; Upadhyaya, H.D.; Varshney, R.K. Diversification of primary gene pool through introgression of resistance to foliar diseases from synthetic amphidiploids to cultivated groundnut (Arachis hypogaea L.). Crop J. 2014, 2, 110–119.
  133. Michelotto, M.D.; de Godoy, I.J.; Pirotta, M.Z.; dos Santos, J.F.; Finoto, E.L.; Pereira Fávero, A. Resistance to thrips (Enneothrips flavens) in wild and amphidiploid Arachis species. PLoS ONE 2017, 12, e0176811.
  134. Bera, S.K.; Chandrashekar, A.; Singh, A. WRKY and Na+/H+ antiporter genes conferring tolerance to salinity in interspecific derivatives of peanut (Arachis hypogaea L.). Aust. J. Crop Sci. 2013, 7, 1173–1180.
  135. Benedito, V.A.; Torres-Jerez, I.; Murray, J.D.; Andriankaja, A.; Allen, S.; Kakar, K.; Wandrey, M.; Verdier, J.; Zuber, H.; Ott, T.; et al. A gene expression atlas of the model legume Medicago truncatula. Plant J. Cell Mol. Biol. 2008, 55, 504–513.
  136. Bouton, J.H. Breeding lucerne for persistence. J. Crop Pasture Sci. 2012, 63, 95–106.
  137. Collino, D.; Dardanelli, J.; de Luca, M.; Racca, R. Temperature and water availability effects on radiation and water use efficiencies in alfalfa (Medicago sativa L.). Aust. J. Exp. Agric. 2005, 45, 383–390.
  138. Cornacchione, M.V.; Suarez, D.L. Emergence, Forage Production, and Ion Relations of Alfalfa in Response to Saline Waters. Crop Sci. 2015, 55, 444–457.
  139. Dear, B.; Reed, K.; Craig, A. Outcomes of the search for new perennial and salt tolerant pasture plants for southern Australia. Aust. J. Exp. Agric 2008, 48, 576–588.
  140. Zhang, W.H.; Longyu, H.; Yang, J.; Shihuan, S.; Mao, X.; Zhang, Q.; Bai, W.; Pan, Q.; Zhou, Q.J.C.S.B. Establishment and management of alfalfa pasture in cold regions of China. Chin. Sci. Bull. 2018, 63, 1651–1663.
  141. Zhang, X.X.; Ren, X.L.; Qi, X.T.; Yang, Z.M.; Feng, X.L.; Zhang, T.; Wang, H.J.; Liang, P.; Jiang, Q.Y.; Yang, W.J.; et al. Evolution of the CBL and CIPK gene families in Medicago: Genome-wide characterization, pervasive duplication, and expression pattern under salt and drought stress. BMC Plant Biol. 2022, 22, 512.
  142. Small, E.; Jomphe, M. A synopsis of the genus Medicago (Leguminosae). Can. J. Bot. 1989, 67, 3260–3294.
  143. Li, H.Y.; Li, Z.Y.; Cai, L.Y.; Shi, W.G.; Mi, F.G.; Shi, F.L. Analysis of genetic diversity of Ruthenia Medic (Medicago ruthenica (L.) Trautv.) in Inner Mongolia using ISSR and SSR markers. Genet. Resour. Crop Evol. 2013, 60, 1687–1694.
  144. Campbell, J.; Pecaut, M.; Luttges, M. Prevalence and arrangement of lignified vascular elements in 6-day-old alfalfa (Medicago sativa L.) seedlings raised in reduced gravity. J. Plant Physiol. 1996, 149, 539–547.
  145. Shu, Y.; Li, W.; Zhao, J.; Liu, Y.; Guo, C. Transcriptome sequencing and expression profiling of genes involved in the response to abiotic stress in Medicago ruthenica. Genet. Mol. Biol. 2018, 41, 638–648.
  146. Wu, R.; Xu, B.; Shi, F. MrERF, MrbZIP, and MrSURNod of Medicago ruthenica Are Involved in Plant Growth and Abiotic Stress Response. Front. Plant Sci. 2022, 13, 907674.
  147. Quan, W.; Liu, X.; Wang, L.; Yin, M.; Yang, L.; Chan, Z. Ectopic expression of Medicago truncatula homeodomain finger protein, MtPHD6, enhances drought tolerance in Arabidopsis. BMC Genom. 2019, 20, 982.
  148. Migicovsky, Z.; Myles, S. Exploiting Wild Relatives for Genomics-assisted Breeding of Perennial Crops. Front. Plant Sci. 2017, 8, 460.
  149. Migicovsky, Z.; Warschefsky, E.; Klein, L.L.; Miller, A.J. Using living germplasm collections to characterize, improve, and conserve woody perennials. Crop Sci. 2019, 59, 2365–2380.
  150. Peace, C.P.; Bianco, L.; Troggio, M.; van de Weg, E.; Howard, N.P.; Cornille, A.; Durel, C.-E.; Myles, S.; Migicovsky, Z.; Schaffer, R.J.; et al. Apple whole genome sequences: Recent advances and new prospects. Hortic. Res. 2019, 6, 59.
  151. Baumgartner, I.O.; Patocchi, A.; Frey, J.; Peil, A.; Kellerhals, M. Breeding Elite Lines of Apple Carrying Pyramided Homozygous Resistance Genes Against Apple Scab and Resistance Against Powdery Mildew and Fire Blight. Plant Mol. Biol. Rep. 2015, 33, 1573–1583.
  152. Geng, D.-L.; Lu, L.-Y.; Yan, M.-J.; Shen, X.-X.; Jiang, L.-J.; Li, H.-Y.; Wang, L.-P.; Yan, Y.; Xu, J.-D.; Li, C.-Y.; et al. Physiological and transcriptomic analyses of roots from Malus sieversii under drought stress. J. Integr. Agric. 2019, 18, 1280–1294.
  153. Rodriguez-Bonilla, L.; Williams, K.A.; Rodríguez Bonilla, F.; Matusinec, D.; Maule, A.; Coe, K.; Wiesman, E.; Diaz-Garcia, L.; Zalapa, J. The Genetic Diversity of Cranberry Crop Wild Relatives, Vaccinium macrocarpon Aiton and V. oxycoccos L., in the US, with Special Emphasis on National Forests. Plants 2020, 9, 1446.
  154. Neyhart, J.L.; Kantar, M.B.; Zalapa, J.; Vorsa, N. Genomic-environmental associations in wild cranberry (Vaccinium macrocarpon Ait.). G3 Genes Genomes Genet. 2022, 12, jkac203.
  155. Walker, M.A.; Riaz, S.; Tenscher, A. Optimizing the breeding of pierce’s disease resistant winegrapes with marker-assisted selection. Acta Hortic. 2014, 1046, 139–143.
  156. Eibach, R.; Zyprian, E.; Welter, L.; Toepfer, R. The use of molecular markers for pyramiding resistance genes in grapevine breeding. Vitis 2007, 46, 120–124.
  157. Migicovsky, Z.; Sawler, J.; Money, D.; Eibach, R.; Miller, A.J.; Luby, J.J.; Jamieson, A.R.; Velasco, D.; von Kintzel, S.; Warner, J.; et al. Genomic ancestry estimation quantifies use of wild species in grape breeding. BMC Genom. 2016, 17, 478.
  158. Hannah, L.; Roehrdanz, P.R.; Ikegami, M.; Shepard, A.V.; Shaw, M.R.; Tabor, G.; Zhi, L.; Marquet, P.A.; Hijmans, R.J. Climate change, wine, and conservation. Proc. Natl. Acad. Sci. USA 2013, 110, 6907–6912.
  159. Morales-Castilla, I.; García de Cortázar-Atauri, I.; Cook, B.I.; Lacombe, T.; Parker, A.; van Leeuwen, C.; Nicholas, K.A.; Wolkovich, E.M. Diversity buffers winegrowing regions from climate change losses. Proc. Natl. Acad. Sci. USA 2020, 117, 2864–2869.
  160. Heinitz, C.; Uretsky, J.; Dodson Peterson, J.; Huerta-Acosta, K.; Walker, M.A. Crop Wild Relatives of Grape (Vitis vinifera L.) Throughout North America. In North American Crop Wild Relatives; Springer: Cham, Switzerland, 2019; Volume 2, pp. 329–351.
  161. Aguirre-Liguori, J.; Morales-Cruz, A.; Gaut, B. Evaluating the persistence and utility of five wild Vitis species in the context of climate change. Mol. Ecol. 2022.
  162. Mudge, K.; Janick, J.; Scofield, S.; Goldschmidt, E.E. A History of Grafting. In Horticultural Reviews; John Wiley & Sons, Inc.: Hoboken, NJ, USA, 2009; pp. 437–493.
  163. Warschefsky, E.J.; Klein, L.L.; Frank, M.H.; Chitwood, D.H.; Londo, J.P.; von Wettberg, E.J.B.; Miller, A.J. Rootstocks: Diversity, Domestication, and Impacts on Shoot Phenotypes. Trends Plant Sci. 2016, 21, 418–437.
More
© Text is available under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/)
Academic Video Service
Feedback