Table of Contents

    Topic review

    Plant Transcription Factors and Drought

    Subjects: Plant Sciences
    View times: 7
    Submitted by: Maria Hrmova

    Definition

    Transcription factors (TFs) play a significant role in signal transduction networks spanning the perception of a stress signal and the expression of corresponding stress-responsive genes. TFs are multi-functional proteins that may simultaneously control numerous pathways during stresses in plants—this makes them powerful tools for the manipulation of regulatory and stress-responsive pathways.

    1. Introduction

    Drought is a major abiotic stress that severely affects crop productivity and distribution. Currently, up to 45% of the world’s agricultural land, where 38% of the world human population resides, is subjected to continuous or frequent drought [1][2]. Water is essential at every stage of plant growth from seed germination to plant maturation, and the shortage of water is the single most important factor that reduces global crop yields, with far-reaching socio-economic consequences [2]. Although under these circumstances, it is challenging to describe drought, in the agricultural context, drought is defined as a prolonged, abnormally dry period when the soil and atmospheric moisture are low, and the ambient air temperature is high, and available water resources are insufficient for agricultural needs [3]. Similarly, Lipiec et al. [4] noted that drought stress occurs when there is an imbalance between evapotranspiration flux and water intake from the soil. Drought with its associated complexity impacts agriculture and contributes heavily to the development of drought-prone areas leading to poor plant growth and reduces crop yields [5][6]. Hence, managing drought is about managing risks that associate with dry-land agriculture, aiming to reduce the impact of drought.
    Considering that drought and related stresses and how they affect plants attract significant research, the understanding of plant protective mechanisms and how they are acquired, is of paramount importance. A large body of data related to drought was published specifically on transcription factors (TFs) and in this review we examine this contested topic in seven inter-related sections.

    2. Natural Variations in Transcription Factors during Drought and Associated Stresses

    There is evidence that abiotic stresses could simultaneously affect plant growth and development [7][8][9][10][11][12][13][14], and that plants evolved sophisticated mechanisms to withstand multiple abiotic stresses due to strong selection to adapt to prevailing conditions [2][15][16][17][18]. Addressing multiple stresses by planned experimentation is a major challenge due to the complexity of exposure to these multiple stresses. To gain an insight into the plant adaptation to various stress-inducing conditions, both natural variation and complex mechanisms underlying stress tolerance/resistance should be considered [19][10][14]. Exploring natural variations contributed significantly towards elucidating the gene function without the confounding effects of expression outside of the natural genomic context [18]. Studies in natural variation provided novel insights into adaptive mechanisms shaping plant stress responses and helped uncover novel loci involved in stress responses [12]. For example, drought-responsive genes showed natural variation and allelic variation on previously described loci and novel loci [20][21]. Rao et al. [20] uncovered two alleles for DREBA1 in Solanum pimpinellifolium, using a screen of 94 genotypes. These alleles together accounted for 25% of trait-associated phenotypic variation [22]. Additional studies of allelic variation in TFs and downstream drought-responsive genes significantly contributed to plant selection and adaptation [23]. Here, GsZFP1, a new C2H2-type zinc-finger TF, was identified in the soybean wild relative Glycine soja [24] and the overexpression of GsZFP1 in alfalfa led to the high expression of various drought-responsive genes [25]. Similarly, Arms et al. [22] mapped a QTL in Solanum habrochaites, a drought-tolerant wild tomato that co-localized to C2H2-type zinc-finger TFs on chromosome 9 of the cultivated tomato. Natural variations were explored in the CBF gene family of complex evolutionary patterns. The CBF regulon consists of three regulatory proteins CBF1, CBF 2, and CBF 3, which play key roles under freezing stress. This was supported by population-level investigations in wild tomato S. peruvianum and S. chilense. Mboup et al. [24] found that CBF3 showed a reduced nucleotide diversity across all populations/species consistent with the strong purifying selection at that locus. Mboup et al. [24] using population-level data also highlighted the complex evolutionary history of CBF genes and showed the advantage of using natural variation to uncover the gene function within a genomic context.
    Currently, phenotyping platforms can be used for screening thousands as opposed to hundreds of individual plants for tolerance traits [26][27][28][29][30]. Natural variation can also be used for understanding the genetic architecture of complex traits such as plant tolerance to stresses. For example, association studies in combination with the genetic disequilibrium linkage, are contributing towards dissecting complex trait loci in plants [31]. This technique highlights more precisely the resolution of genome-wide association studies (GWAS) at the gene level, subject to the availability of high-density and genome-wide DNA markers [32]. Additionally, after genome-scale sequencings of large numbers of varieties with different genetic backgrounds are available, GWAS accelerates the genetic dissection of complex traits in crops using natural variations [33][32]. Similarly, Yan et al. [30] suggested the candidate gene association analysis as one of the methods of choice for the discovery and detection of single nucleotide polymorphism. This technique ensures that markers are within or closely linked to genes that contribute to complex traits [30].

    3. Conclusions and Outlook

    In this review, we examined the aspects of plant tolerance to extreme abiotic stresses such as drought and how stress-inducible TFs participate in drought, which in turn regulate the expression of a large array of downstream genes. We advocate that TFs are powerful tools for genetic engineering as their controlled expression can lead to the up- or downregulation of genes under their control. The discovery and descriptions of structure-function relationships of several classes of plant TFs aided in the identification of pathways that control the plasticity of plant growth and control the modulation of plant development in response to abiotic stress. However, the work on plant defense mechanisms controlled by TFs is ongoing. While we need to acknowledge that the progress on molecular mechanisms of TFs progresses, in the future, we need to provide precise molecular descriptions of the function of TFs to understand their precise biological roles. It will be critical to describe: (i) Molecular basis of formation of transcriptional activation and repression complexes, and the influence of post-translational modifications on the formation of these complexes; (ii) mechanisms of activation and repression of target genes, of how TFs form oligomeric assemblies; (iii) 3D structures and folding pathways of TFs, and how structural determinants play roles in DNA recognition and in the activation of complexes; (iv) mechanisms on how these complexes are regulated. Answers to these questions will allow us to develop modified versions of TFs with improved DNA-binding properties and create TFs that will be independent of other upstream regulatory pathways. This information will be useful to define the mechanisms of formation of functional complexes of TFs, and most importantly, the new knowledge could hold promises for informed decisions on suitable TF applications to bioengineer plants with enhanced tolerance to drought and other abiotic stresses.

    The entry is from 10.3390/ijms22115662

    References

    1. Bartels, D. Current status and implications of engineering drought tolerance in plants using transgenic approaches. CAB Rev. Perspect. Agric. Veter. Sci. Nutr. Nat. Resour. 2008, 3.
    2. Hussain, S.S.; Raza, H.; Afzal, I.; Kayani, M.A. Transgenic plants for abiotic stress tolerance: Current status. Arch. Agron. Soil Sci. 2011, 58, 693–721.
    3. Australian Government—Bureau of Meteorology. 2012. Available online: (accessed on 14 April 2021).
    4. Lipiec, J.; Doussan, C.; Nosalewicz, A.; Kondracka, K. Effect of drought and heat stresses on plant growth and yield: A review. Int. Agrophysics 2013, 27, 463–477.
    5. Zhao, C.; Liu, B.; Piao, S.; Wang, X.; Lobell, D.B.; Huang, Y.; Huang, M.; Yao, Y.; Bassu, S.; Ciais, P.; et al. Temperature increase reduces global yields of major crops in four independent estimates. Proc. Natl. Acad. Sci. USA 2017, 114, 9326–9331.
    6. Hrmova, M.; Lopato, S. Enhancing abiotic stress tolerance in plants by modulating properties of stress responsive transcription factors. In Genomics of Plant Genetic Resources. Part II: Crop Productivity, Food Security and Nutritional Quality; Tuberosa, R., Granerm, A., Frisonm, E., Eds.; Springer: Dordrecht, The Netherlands, 2014; Volume 2, pp. 291–316.
    7. Hussain, S.S.; Siddique, K.H.M.; Lopato, S. Towards integration of bacterial genomics in plants for enhanced abiotic stress tolerance: Clues from transgenics. Adv. Environ. Res. 2014, 33, 65–122.
    8. Sewelam, N.; Oshima, Y.; Mitsuda, N.; Ohme-Takagi, M. A step towards understanding plant responses to multiple environmental stresses: A genome-wide study. Plant Cell Environ. 2014, 37, 2024–2035.
    9. Suzuki, N.; Rivero, R.M.; Shulaev, V.; Blumwald, E.; Mittler, R. Abiotic and biotic stress combinations. New Phytol. 2014, 203, 32–43.
    10. Thoen, M.P.M.; Olivas, N.H.D.; Kloth, K.J.; Coolen, S.; Huang, P.-P.; Aarts, M.G.M.; Bac-Molenaar, J.A.; Bakker, J.; Bouwmeester, H.J.; Broekgaarden, C.; et al. Genetic architecture of plant stress resistance: Multi-trait genome-wide association mapping. New Phytol. 2016, 213, 1346–1362.
    11. Stam, J.M.; Kroes, A.; Li, Y.; Gols, R.; Van Loon, J.J.; Poelman, E.H.; Dicke, M. Plant Interactions with Multiple Insect Herbivores: From Community to Genes. Annu. Rev. Plant Biol. 2014, 65, 689–713.
    12. Brachi, B.; Meyer, C.G.; Villoutreix, R.; Platt, A.; Morton, T.C.; Roux, F.; Bergelson, J.; Zhang, X.; Gui, L.; Zhang, X.; et al. Coselected genes determine adaptive variation in herbivore resistance throughout the native range of Arabidopsis thaliana. Proc. Natl. Acad. Sci. USA 2015, 112, 4032–4037.
    13. Kerwin, R.; Feusier, J.; Corwin, J.; Rubin, M.; Lin, C.; Muok, A.; Larson, B.; Li, B.; Joseph, B.; Francisco, M.; et al. Natural genetic variation in Arabidopsis thaliana defense metabolism genes modulates field fitness. eLife 2015, 4, e05604.
    14. Todaka, D.; Shinozaki, K.; Yamaguchi-Shinozaki, K. Recent advances in the dissection of drought-stress regulatory networks and strategies for development of drought-tolerant transgenic rice plants. Front. Plant Sci. 2015, 6, 84.
    15. Hussain, S.S.; Kayani, M.A.; Amjad, M. Transcription factors as tools to engineer enhanced drought stress tolerance in plants. Biotechnol. Prog. 2011, 27, 297–306.
    16. Kalladan, R.; Lasky, J.R.; Chang, T.Z.; Sharma, S.; Juenger, T.E.; Verslues, P.E. Natural variation identifies genes affecting drought-induced abscisic acid accumulation in Arabidopsis thaliana. Proc. Natl. Acad. Sci. USA 2017, 114, 11536–11541.
    17. Mickelbart, M.V.; Hasegawa, P.M.; Bailey-Serres, J. Genetic mechanisms of abiotic stress tolerance that translate to crop yield stability. Nat. Rev. Genet. 2015, 16, 237–251.
    18. 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. 2016, 10, 5–24.
    19. Alonso-Blanco, C.; Aarts, M.G.; Bentsink, L.; Keurentjes, J.J.; Reymond, M.; Vreugdenhil, D.; Koornneef, M. What Has Natural Variation Taught Us about Plant Development, Physiology, and Adaptation? Plant Cell 2009, 21, 1877–1896.
    20. 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.
    21. Luo, X.; Bai, X.; Zhu, D.; Li, Y.; Ji, W.; Cai, H.; Wu, J.; Liu, B.; Zhu, Y. GsZFP1, a new Cys2/His2-type zinc-finger protein, is a positive regulator of plant tolerance to cold and drought stress. Planta 2011, 235, 1141–1155.
    22. Arms, E.M.; Bloom, A.J.; Clair, D.A.S. High-resolution mapping of a major effect QTL from wild tomato Solanum habrochaites that influences water relations under root chilling. Theor. Appl. Genet. 2015, 128, 1713–1724.
    23. Dubos, C.; Stracke, R.; Grotewold, E.; Weisshaar, B.; Martin, C.; Lepiniec, L. MYB transcription factors in Arabidopsis. Trends Plant Sci. 2010, 15, 573–581.
    24. Mboup, M.; Fischer, I.; Lainer, H.; Stephan, W. Trans-Species Polymorphism and Allele-Specific Expression in the CBF Gene Family of Wild Tomatoes. Mol. Biol. Evol. 2012, 29, 3641–3652.
    25. Tang, L.; Cai, H.; Ji, W.; Luo, X.; Wang, Z.; Wu, J.; Wang, X.; Cui, L.; Wang, Y.; Zhu, Y.; et al. Overexpression of GsZFP1 enhances salt and drought tolerance in transgenic alfalfa (Medicago sativa L.). Plant Physiol. Biochem. 2013, 71, 22–30.
    26. Fiorani, F.; Schurr, U. Future Scenarios for Plant Phenotyping. Annu. Rev. Plant Biol. 2013, 64, 267–291.
    27. Granier, C.; Vile, D. Phenotyping and beyond: Modelling the relationships between traits. Curr. Opin. Plant Biol. 2014, 18, 96–102.
    28. Kloth, K.J.; Broeke, C.J.T.; Thoen, M.P.; Brink, M.H.-V.D.; Wiegers, G.L.; E Krips, O.; Noldus, L.P.; Dicke, M.; Jongsma, M.A. High-throughput phenotyping of plant resistance to aphids by automated video tracking. Plant Methods 2015, 11, 4.
    29. Atwell, S.; Huang, Y.S.; Vilhjálmsson, B.J.; Willems, G.; Horton, M.; Li, Y.; Meng, D.; Platt, A.; Tarone, A.M.; Hu, T.T.; et al. Genome-wide association study of 107 phenotypes in Arabidopsis thaliana inbred lines. Nat. Cell Biol. 2010, 465, 627–631.
    30. Yan, J.; Warburton, M.; Crouch, J. Association Mapping for Enhancing Maize (Zea mays L.) Genetic Improvement. Crop. Sci. 2011, 51, 433–449.
    31. Li, Q.; Yang, X.; Xu, S.; Cai, Y.; Zhang, D.; Han, Y.; Li, L.; Zhang, Z.; Gao, S.; Li, J.; et al. Genome-Wide Association Studies Identified Three Independent Polymorphisms Associated with α-Tocopherol Content in Maize Kernels. PLoS ONE 2012, 7, e36807.
    32. Li, H.; Peng, Z.; Yang, X.; Wang, W.; Fu, J.; Wang, J.; Han, Y.; Chai, Y.; Guo, T.; Yang, N.; et al. Genome-wide association study dissects the genetic architecture of oil biosynthesis in maize kernels. Nat. Genet. 2013, 45, 43–50.
    33. Huang, G.-T.; Ma, S.-L.; Bai, L.-P.; Zhang, L.; Ma, H.; Jia, P.; Liu, J.; Zhong, M.; Guo, Z.-F. Signal transduction during cold, salt, and drought stresses in plants. Mol. Biol. Rep. 2012, 39, 969–987.
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