Chestnuts | Encyclopedia MDPI

Chestnuts: Comparison

Please note this is a comparison between Version 1 by GABRIELE BECCARO and Version 2 by Catherine Yang.

Chestnuts (Castanea spp.) are trees of relevant economic interest in the agro-sylvicultural contexts of mountain regions throughout the temperate zone, particularly in the northern hemisphere.

Castanea spp.
defensive mutualism
endophytes

1. Introduction

Chestnuts (Castanea spp.) are geographically distributed in three main areas throughout the world (Asia, Europe, North America) where they have an invaluable cultural heritage but also an important economic and environmental role in many agroforestry systems. Their nuts provided for centuries a dietary staple in rural areas and, when dried, a stored food for the whole year; the wood is still today used as firewood or building timber.

The genus Castanea (x = 12, 2n = 24), chestnuts and chinkapins, belongs to the Fagaceae (Cupuliferae) family, which includes 6 genera (Castanea, Quercus, Castanopsis, Fagus, Nothofagus, Lithocarpus) and approximately 1000 species. It is closely related to the genus Castanopsis [1], is widespread in the boreal hemisphere and encompasses 13 species. The natural distribution of the European or sweet chestnut (C. sativa) covers Europe and some Mediterranean countries. In China, Japan, Vietnam, North and South Korea C. mollissima, C. crenata, C. seguinii, C. henryi occur. In North America, C. dentata is still present only along the Appalachian Mountains, due to the devastating impact of the chestnut blight. Castanea pumila is found in the southeastern United States ^[2][3][2,3].

Castanea species show different ecological and morphological traits, vegetative habit, wood and nut characteristics, pedoclimatic adaptability, resilience and resistance to biotic and abiotic stresses, reflecting the adaptation of this genus to different environmental conditions [4]. The main cultivated species are C. sativa, C. mollissima and C. crenata, due to their large nut size, and marroni cultivars (C. sativa) are considered the most commercially valuable. Castanea sativa and C. dentata are also cultivated for timber production, whilst many interspecific hybrids are used for nut production or as rootstocks [5].

2. Ecological and Technical Features of Chestnut Orchards

The ecological features of chestnut orchards, their agronomic management and architecture strongly depend on species and country. The best soils for chestnut are deep, soft, volcanic in origin, and rich in phosphorus, potassium, and organic matter. The soil pH should be in the range 5.0−6.5; therefore, soils with active limestone are not optimal, because Castanea species are very sensitive to high pH values. Soil permeability is very important. In fact, the crop performs better in well-drained, loam to sandy-loam soils, while heavy, washed out, clayey, stagnant soils which favor root rot must be avoided [6]. Chestnut tolerates cold winters and requires average temperature of 8–15 °C, with a monthly average of 10 °C for at least six months. Castanea sativa is more cold-resistant (−15 to −20 °C) than the Euro-Japanese hybrids. Despite late bud-break (March–April in the Northern Hemisphere), the trees may be prone to spring frosts which damage young shoots. Temperatures of 27−30 °C are necessary during pollination. European and Japanese cultivars require about 800–900 mm/year of rainfall, well distributed during the growing season, while Euro-Japanese hybrids and C. mollissima are much more waterdemanding (1200–1300 mm/year). In temperate climates, sweet chestnut should not be planted above 800–900 m, while for hybrids the maximum altitude is about 500–600 m [5]. Ecological features of a chestnut orchard can be influenced by many natural and anthropogenic parameters, such as soil, climate, rootstock, cultivar, cover crops, irrigation system and fertilization [7]. Concerning soil, an increase in the organic matter content is often obtained through sheep and cattle pasture, outside the harvesting period, or with the use of manure (10–15 tons/ha/year). Mown grass, leaves, husks and the small pruned material are often left on the ground as they provide further enrichment in organic matter. Fertilization of the orchard is every year carried out according to soil conditions and uptakes [8]. Biological or conventional management are both adopted by chestnut growers and could strongly influence the crop ecological features. The orchard model, traditional or intensive, could also strongly influence the crop ecological features. Traditional orchards are mainly located in mountainous areas while intensive orchards are a relatively recent practice and are usually located in lowlands, quite far from the typical ecological conditions of the species [9]. For all species, except in traditional European chestnut orchards, the general trend is to increase plant density to develop in a relatively short time maximum bearing per unit area. Plantation density can affect the orchard microclimatic conditions and can range from 100 to 550 trees/ha, based on species, variety, genotype-environment interactions and cultural practices. For traditional plantations of C. sativa, spacing ranges from 8–10 m apart in rows and 8–12 m between rows. For the most vigorous Euro-Japanese hybrids the distances range between 7 × 8 m (178 trees/ha) and 8 × 10 m (125 trees/ha). Castanea sativa and the Euro-Japanese hybrids can be cultivated in high density plantations (3 m × 10 m). For C. crenata distances of about 5 × 7 m (285 trees/ha, in deep fertile soils) or 7 × 7 m (204 trees/ha) are recommended. Castanea mollissima, grown in China and the Unites States, is managed in a high or semi-high density scheme, due to the smaller tree size. Planting patterns may be rectangular, squared or triangular, but the first scheme is mostly used because of easier management [3]. Nowadays, many traditional plantations need renewal and recovery after years of abandonment or following the attacks of pests and diseases that have compromised their efficiency.

3. Occurrence of Endophytic Fungi in Chestnuts and Ecological Implications

Although characterized by synchronized development inside the plant tissues and nutrient transfer at the interfaces ^[10][26], EMF are not included in the category of endophytes since at some extent they also grow saprophytically in the soil. Conversely, the definition of endophytes, on which this paper is more specifically centered, does not reflect a specialized nutritional function, and it is conventionally applied to microorganisms that colonize living, internal tissues of plants without causing any immediate, overt negative effect ^[11][27]. Data concerning occurrence of endophytic fungi of chestnuts (Table 1) are only available from a low number of countries, indicating that consideration for the ecological implications and the economic impact related to this component of biodiversity is still quite limited. Possibly connected with a higher importance as an economic crop in Europe, most investigations have been carried out on C. sativa, with 76 taxa reported so far (2/3 of which identified at the species level), while the species C. crenata, C. dentata and C. mollissima appear to have been less frequently investigated, basically in Japan, the United States and China. As a general aspect, identifications concerning stem (shoots, branches, etc.) refer to the occurrence of endophytes in subcortical tissues, while no findings were reported from xylem ^[12][13][28,29]. In some cases, conditions of detection did not fully meet the basic requirements referring to the true endophytic condition. In fact, a recent study based on ITS meta-barcoding was addressed to establish whether fungal communities within cynipid galls are different from foliar endophytes. Unfortunately, results were basically presented with reference to classes to which the detected OTUs belong, and identifications at the species level was only carried out for the main OTUs, without distinguishing their origin (gall or leaf) ^[14][30]. Therefore, entries in Table 1 referring to this study must be taken with circumspection. Moreover, some uncertainty is entailed in a few reports concerning endophytic fungi associated with cankers produced by C. parasitica on both C. sativa and C. dentata ^{[15][16][17][18][19][20]}[31,32,33,34,35,36]. Even if in these cases the plant material used for isolations was not asymptomatic following infection by a known pathogen, the sterilization procedure ensured that at least the isolated fungi had colonized the plant tissues before sampling and were not epiphytic contaminants.

Table 1.

Endophytic fungi reported from

Castanea

spp.

Endophyte	¹	Plant Part	Country	Reference

Castanea sativa
Acremonium	cf.	curvulum	shoot (phellem)	Bellinzona, Switzerland	^[12]	[28]
Alternaria alternata	several plant parts	Eurobin and Monbulk, Australia	^[21]	[37]
	shoot	Ticino, Switzerland	^[22]	[38]
	bud	Ankara, Turkey	^[23]	[39]
	bark	Vinhais, Portugal	^[24]	[40]
Alternaria	sp.	shoot	Geneve and Ticino, Switzerland	^[25]	[41]
		leaf or gall	Southern Tuscany, Italy	^[14]	[30]
		bud	Ankara, Turkey	^[23]	[39]
Apiognomonia errabunda	leaf	Cureglia and Zarei, Switzerland	^[26]	[42]
Arcopilus aureus *	bark	Vinhais, Portugal	^[24]	[40]
Arthrinium arundinis	leaf	Vejoris, Spain	^[27]	[43]
Aspergillus	sp.	stem	Black Sea region, Turkey	^[15]	[31]
Aspergillus	sp.	bud	Ankara, Turkey	^[23]	[39]
Asterosporium	sp.	shoot (phellem)	Bellinzona, Switzerland	^[12]	[28]
Aureobasidium pullulans	shoot	Ticino, Switzerland	^[22]^[25]	[38,41]
Aureobasidium	sp.	bud	Ankara, Turkey	^[23]	[39]
Biscogniauxia mediterranea	bark	Valpaços and Vinhais, Portugal	^[24]	[40]
Botryosphaeria dothidea	shoot	Ticino, Switzerland	^[25]	[41]
Botryosphaeria dothidea	leaf or gall	Southern Tuscany, Italy	^[14]	[30]
Botryosphaeria	sp.	several plant parts	Eurobin and Monbulk, Australia	^[21]	[37]
Botryotinia pelargonii	leaf or gall	Southern Tuscany, Italy	^[14]	[30]
Botrytis cinerea	several plant parts	Eurobin and Monbulk, Australia	^[21]	[37]
Chaetomium	sp.	several plant parts	Eurobin and Monbulk, Australia	^[21]	[37]
Cladosporium cladosporioides	several plant parts	Eurobin and Monbulk, Australia	^[21]	[37]
Cladosporium	sp.	fruit	Eurobin and Monbulk, Australia	^[21]	[37]
Cladosporium	sp.	bud	Ankara, Turkey	^[23]	[39]
Colletotrichum acutatum	shoot (phellem)	Bellinzona, Switzerland	^[12]	[28]
	leaf, shoot	Monti Cimini, Italy	^[28]	[44]
	leaf	Vejoris, Spain	^[27]	[43]
Coprinellus domesticus	bark	Oghuz, Azerbaijan	^[17]	[33]
Coryneum modonium	shoot (phellem)	Bellinzona and Murg, Switzerland	^[12]	[28]
Cryphonectria parasitica	shoot (phellem)	Bellinzona, Switzerland	^[12]	[28]
	sprout	Fossemagne, France	^[29]	[45]
	bark	Valpaços and Vinhais, Portugal	^[24]	[40]
Cytospora chrysosperma	bark	Valpaços, Portugal	^[24]	[40]
Cytospora diatyrpelloidea	bark	Valpaços and Vinhais, Portugal	^[24]	[40]
Cytospora eucalypticola	bark	Valpaços, Portugal	^[24]	[40]
Cytospora quercicola	bark	Vinhais, Portugal	^[24]	[40]
Dendrostoma castaneum *	shoot (phellem)	Bellinzona and Murg, Switzerland	^[12]	[28]
	fruit	Toricella, Switzerland	^[30]	[46]
	branch	Astroni Nature Reserve, Italy	^[31]	[47]
Diaporthe amygdali	bark	Oghuz, Azerbaijan	^[17]	[33]
Diaporthe eres	shoot	Geneve and Ticino, Switzerland	^[22]^[25]	[38,41]
Diaporthe foeniculina	branch	Astroni Nature Reserve, Italy	^[32]	[48]
Diaporthe	sp.	shoot (phellem)	Bellinzona and Murg, Switzerland	^[12]	[28]
		leaf or gall	Southern Tuscany, Italy	^[14]	[30]
		bud	Ankara, Turkey	^[23]	[39]
Diplodia seriata	leaf or gall	Southern Tuscany, Italy	^[14]	[30]
Diplodina castaneae	*	shoot (phellem)	Bellinzona and Murg, Switzerland	^[12]	[28]
		stem, twig	Chablais and Ticino, Switzerland	^[32]	[48]
		stem	Northern Spain	^[32]	[48]
		bark, stem	Ismailly, Qabala, Sheki (Azerbaijan)	^[17]	[33]
Epicoccum nigrum	several plant parts	Eurobin and Monbulk, Australia	^[21]	[37]
	bark	Balakan, Azerbaijan	^[17]	[33]
	bud	Ankara, Turkey	^[23]	[39]
Eutypella	sp.	bark	Zagatala, Azerbaijan	^[17]	[33]
Fusarium ciliatum	leaf or gall	Southern Tuscany, Italy	^[14]	[30]
Fusarium lateritium	leaf or gall	Southern Tuscany, Italy	^[14]	[30]
Fusarium oxysporum	leaf or gall	Southern Tuscany, Italy	^[14]	[30]
Fusarium	sp.	fruit	Eurobin and Monbulk, Australia	^[21]	[37]
		leaf or gall	Southern Tuscany, Italy	^[14]	[30]
		leaf	Vejoris, Spain	^[27]	[43]
		bud	Ankara, Turkey	^[23]	[39]
Gnomoniopsis castaneae	*	several plant parts	Eurobin and Monbulk, Australia	^[21]	[37]
		bark, flower, leaf	several locations in New Zealand	^[13]	[29]
		several plant parts	Cuneo province, Italy	^[33]^[34]	[49,50]
		flower, leaf, stem	Southern Australia	^[35]	[51]
		shoot	several locations in Northern Italy	^[36]	[52]
		fruit	several locations in Switzerland	^[37]	[53]
		buds	Aosta Valley and Piedmont, Italy	^[38]	[54]
		shoot	Geneve and Ticino, Switzerland	^[22]^[25]	[38,41]
		several plant parts	Monti Cimini, Italy	^[28]^[39]	[44,55]
		leaf or gall	Southern Tuscany, Italy	^[14]	[30]
		leaf	Vejoris, Spain	^[27]	[43]
		leaf	Netherlands	^[40]	[56]
		branch	Astroni Nature Reserve, Italy	^[31]	[47]
Hyphodermella rosae	bark	Ismailly and Shaki, Azerbaijan	^[17]	[33]
Hypoxylon fragiforme	shoot (phellem)	Bellinzona and Murg, Switzerland	^[12]	[28]
Irpex lacteus	bark	Balakan, Azerbaijan	^[17]	[33]
Jattaea	sp.	bark	Zagatala, Azerbaijan	^[17]	[33]
Massarina	cf.	quercina	shoot (phellem)	Murg, Switzerland	^[12]	[28]
Mollisia	sp. (=	Cystodendron	sp.)	shoot (phellem)	Bellinzona, Switzerland	^[12]^[41]	[28,57]
Monodictys castaneae	shoot (phellem)	Bellinzona, Switzerland	^[12]	[28]
Mucor fragilis	bark	Vinhais, Portugal	^[24]	[40]
Neocucurbitaria cava	*	leaf or gall	Southern Tuscany, Italy	^[14]	[30]
Neopestalotiopsis	sp.	bark	Asturias, Spain	^[19]	[35]
Neopestalotiopsis zimbabwana	bark	Asturias, Spain	^[19]	[35]
Nigrospora	sp.	several plant parts	Eurobin and Monbulk, Australia	^[21]	[37]
Ophiovalsa	cf.	suffusa	shoot (lenticel)	Bellinzona, Switzerland	^[12]	[28]
Paraconiothyrium brasiliense	bark	Vinhais, Portugal	^[24]	[40]
Paraconiothyrium brasiliense	branch	Astroni Nature Reserve, Italy	^[31]	[47]
Penicillium glabrum	bark	Vinhais, Portugal	^[24]	[40]
Penicillium	sp.	several plant parts	Eurobin and Monbulk, Australia	^[21]	[37]
		stem	Black Sea region, Turkey	^[15]	[31]
		bark	Marche, Italy	^[18]	[34]
		bud	Ankara, Turkey	^[23]	[39]
		bark	Valpaços, Portugal	^[24]	[40]
		branch	Astroni Nature Reserve, Italy	^[31]	[47]
Pestalotiopsis	sp.	leaf	Vejoris, Spain	^[27]	[43]
		bark	Asturias, Spain	^[19]	[35]
		bud	Ankara, Turkey	^[23]	[39]
Pezicula cinnamomea	shoot (phellem)	Bellinzona and Murg, Switzerland	^[12]	[28]
Phaeococcus	sp.	shoot (phellem)	Murg, Switzerland	^[12]	[28]
Phoma	sp.	shoot (phellem)	Bellinzona, Switzerland	^[12]	[28]
		several plant parts	Eurobin and Monbulk, Australia	^[21]	[37]
		bud	Ankara, Turkey	^[23]	[39]
Pilidiella castaneicola	*	shoot	Bellinzona and Murg, Switzerland	^[12]	[28]
Ramichloridium	sp.	shoot (phellem)	Murg, Switzerland	^[12]	[28]
Rhizoctonia	sp.	shoot (phellem)	Bellinzona, Switzerland	^[12]	[28]
Rhizopus	sp.	bark	Vinhais, Portugal	^[24]	[40]
Sclerotinia pseudotuberosa	bark, bud, fruit	Viterbo province, Italy	^[42]	[58]
Sordaria rabenhorstii	*	bark	Valpaços, Portugal	^[24]	[40]
Sordaria	sp.	several plant parts	Eurobin and Monbulk, Australia	^[21]	[37]
Sordaria	sp.	leaf or gall	Southern Tuscany, Italy	^[14]	[30]
Stemphylium vesicarium	leaf or gall	Southern Tuscany, Italy	^[14]	[30]
Trichoderma atroviride	scion	Ticino, Switzerland	^[22]	[38]
Trichoderma atroviride	leaf	Vejoris, Spain	^[27]	[43]
Trichoderma hamatum	shoot	Ticino, Switzerland	^[22]	[38]
Trichoderma koningiopsis	bark	Shaki, Azerbaijan	^[17]	[33]
Trichoderma	sp.	stem	Black Sea region, Turkey	^[15]	[31]
		bark	Qakh, Azerbaijan	^[17]	[33]
		bark	Marche, Italy	^[18]	[34]
Trichothecium roseum	leaf or gall	Southern Tuscany, Italy	^[14]	[30]
Umbelopsis isabellina	bark	Balakan and Qabala, Azerbaijan	^[17]	[33]
Umbelopsis isabellina	bark	Vinhais, Portugal	^[24]	[40]
Xenoacremonium falcatum	bark	Balakan and Qabala, Azerbaijan	^[17]	[33]
Xylaria	sp.	branch	Astroni Nature Reserve, Italy	^[31]	[47]
Castanea crenata
Alternaria	sp.	leaf	Kashiwa, Japan	^[43]	[59]
Astrocystis	sp.	leaf	Kashiwa, Japan	^[43]	[59]
Aureobasidium	sp.	leaf	Kashiwa, Japan	^[43]	[59]
Botryosphaeria dothidea	leaf	Kashiwa, Japan	^[43]	[59]
Colletotrichum acutatum	leaf	Kashiwa, Japan	^[43]	[59]
Colletotrichum gloeosporioides	leaf	Kashiwa, Japan	^[43]	[59]
Diaporthe	sp.	leaf	Kashiwa, Japan	^[43]	[59]
Discula	sp.	leaf	Kashiwa, Japan	^[43]	[59]
Glomerella	sp.	leaf	Kashiwa, Japan	^[43]	[59]
Gnomoniopsis castaneae	*	bark, flower, leaf	several locations in New Zealand	^[13]	[29]
Induratia fengyangensis	*	leaf	Kashiwa, Japan	^[43]	[59]
Nigrospora	sp.	leaf	Kashiwa, Japan	^[43]	[59]
Pestalotiopsis	sp.	leaf	Kashiwa, Japan	^[43]	[59]
Phyllosticta capitalensis	leaf	Kashiwa, Japan	^[43]	[59]
Xylaria	sp.	leaf	Kashiwa, Japan	^[43]	[59]
Castanea dentata
Acremonium implicatum	*	stem	Michigan and Wisconsin, USA	^[20]	[36]
Alternaria alternata	stem	Michigan and Wisconsin, USA	^[20]	[36]
Alternaria brassicae	stem	Michigan and Wisconsin, USA	^[20]	[36]
Aspergillus tubingensis	stem	Michigan, USA	^[44]	[60]
Biscogniauxia	aff.	mediterranea	stem	Michigan and North Carolina, USA	^[44]	[60]
Botryosphaeria	sp.	stem	Michigan and Wisconsin, USA	^[16]^[20]	[32,36]
Daldinia	aff.	childiae	stem	Michigan, USA	^[44]	[60]
Didimostylbe	sp.	stem	Wisconsin, USA	^[16]	[32]
Diplodia corticola	stem	Michigan and Wisconsin, USA	^[20]	[36]
Diplodia seriata	stem	Michigan and Wisconsin, USA	^[20]	[36]
Dothiorella	sp.	stem	Wisconsin, USA	^[16]	[32]
Epicoccum nigrum	stem	Wisconsin, USA	^[16]	[32]
	stem	Michigan, USA	^[44]	[60]
	stem	Michigan and Wisconsin, USA	^[45]	[61]
Fusarium	sp.	stem	Massachusetts, USA	^[46]	[62]
Gnomoniopsis castaneae	*	flower, leaf	Ohaupo, New Zealand	^[13]	[29]
Gnomoniopsis castaneae	*	stem	Michigan and Wisconsin, USA	^[20]	[36]
Mucor circinelloides	stem	Michigan and Wisconsin, USA	^[20]	[36]
Mucor fragilis	stem	Michigan and Wisconsin, USA	^[20]	[36]
Nectria cinnabarina	stem	Michigan and Wisconsin, USA	^[20]	[36]
Nigrospora	aff.	oryzae	stem	Michigan, USA	^[44]	[60]
Paraconiothyrium	sp.	stem	Wisconsin, USA	^[16]	[32]
Penicillium glabrum	stem	Michigan and Wisconsin, USA	^[16]^[20]	[32,36]
Penicillium spinulosum	stem	Michigan and Wisconsin, USA	^[16]^[20]	[32,36]
Pestalotia	sp.	stem	Wisconsin, USA	^[15]	[31]
Pestalotiopsis	sp.	stem	North Carolina, USA	^[44]	[60]
Pezicula cinnamomea	stem	Michigan and Wisconsin, USA	^[20]	[36]
Pezicula ericae	stem	Michigan and Wisconsin, USA	^[20]	[36]
Pezicula sporulosa	stem	North Carolina, USA	^[44]	[60]
Strasseria	sp.	stem	Michigan and Wisconsin, USA	^[20]	[36]
Trichoderma atroviride	stem	Michigan and Wisconsin, USA	^[16]^[20]	[32,36]
Trichoderma aureoviride	stem	Wisconsin, USA	^[16]	[32]
Trichoderma citrinoviride	stem	Michigan and Wisconsin, USA	^[20]	[36]
Trichoderma harzianum	stem	Michigan and Wisconsin, USA	^[20]	[36]
Trichoderma	sp.	stem	Massachusetts, USA	^[46]	[62]
Tubakia suttoniana	*	stem	North Carolina, USA	^[43]	[59]
Umbelopsis isabellina	stem	Michigan and Wisconsin, USA	^[16]^[20]^[45]	[32,36,61]
Castanea mollissima
Alternaria eichhorniae	leaf	Qing Long, China	^[47]	[63]
Alternaria	sp.	leaf	Qing Long, China	^[47]	[63]
Auriculibuller fuscus	*	leaf	Qing Long, China	^[47]	[63]
Cercospora canescens	twig	Qing Long, China	^[47]	[63]
Cercospora	sp.	twig	Qing Long, China	^[47]	[63]
Colacogloea	sp.	leaf	Qing Long, China	^[47]	[63]
Colacogloea terpenoidalis	leaf	Qing Long, China	^[47]	[63]
Gnomoniopsis castaneae	*	bark, leaf	Ohaupo, New Zealand	^[13]	[29]
Kondoa sorbi	leaf	Qing Long, China	^[47]	[63]
Kondoa	sp.	twig	Qing Long, China	^[47]	[63]
Papiliotrema	sp.	leaf	Qing Long, China	^[47]	[63]
Phlebia acerina	-	China	^[48]	[64]
Sporobolomyces roseus	twig	Qing Long, China	^[47]	[63]

¹ Underlined species are also known as disease agents of chestnuts. * Names with an asterisk are the latest accepted for these species, which are different from the ones used in the corresponding references.