Didymella exigua
Didymella exigua (Niessl) Sacc., Michelia 2: 57 (1880).
≡ Didymosphaeria exigua Niessl, Oesterr. Bot. Z. 25: 165 (1875).
Index Fungorum number: IF 218525; Facesoffungi number: FoF 11503, Fig.1
Description: see Chen et al. (2015).
Material considered: see Chen et al. (2015).
Fig. 1 Didymella macrostoma (MFLU 15-1319, holotype). a Ascomata on host surface. b Section through ascoma. c Peridium. d, e Asci with ascospores. f, g Ascospores. h Conidiomata in culture. i Section through conidioma. j–l Conidiogenous cells. m Conidia. Scale bars: b, i = 100 μm, c = 20 μm, d, e = 30 μm, f, g, j–m = 10 µm.
Importance and distribution
There are 417 epithets in Index Fungorum (2022), but many species have been transferred to other genera such as Apiosporella, Arthopyrenia, Cercidospora, Constrictolumina, Didymellopsis, Didymolepta, Discostroma, Fenestella, Frigidopyrenia, Gnomoniopsis, Isothea, Keissleriella, Leptorhaphis, Leptosphaeria, Lichenochora, Longipedicellata, Lophiostoma, Monascostroma, Mycoporum, Mycosphaerella, Naetrocymbe, Neoascochyta, Neodidymelliopsis, Oxydothis, Paraboeremia, Phoma, Phomatospora, Prolisea, Pseudomassaria, Pseudosagedia, Seimatosporium, Septoria, Sphaerellothecium, Stagonosporopsis, Xenodidymella and Zwackhiomyces. Members of Didymella are ubiquitous and can be saprobes, pathogens and endophytes on a wide range of plants (Aveskamp et al. 2010; Chen et al. 2015, 2017; Jayasiri et al. 2017). Important diseases caused by Didymella include gummy stem blight of watermelon (Citrullus lanatus) caused by D. bryoniae (Sudisha et al. 2004; Basim et al. 2016), canker of tomato by D. lycopersici (Besri 1982), and tea leaf spot in China by D. bellidis (Wang et al. 2020). Didymella has worldwide distribution.
Industrial relevance and applications
Didymella is beneficial to medical and pharmaceutical industry as it produces nonenolide which has antimalarial activity (Cimmino et al. 2012)
Biochemical importance of the genus, chemical diversity or applications
Didymella produces wide range of chemicals such as Didymellanosine, a decahydrofluorene analogue, and ascolactone C from Didymella sp. IEA-3B.1, an endophyte of Terminalia catappa (Ariantari et al. 2020) and Pinolide, a Nonenolide produced by Didymella pinodes. Luo et al. (2020) reported several chemicals such as didymelol B-D, naphthalenone, didymelol A, naphthols, naphthalenones namely (3S,4R)-3,4,6-trihydroxy-3,4-dihydronaphthalen-1(2H)-one, (4S)-4,6-dihydroxy-3,4-dihydronaphthalen-1(2H)-one, (4S)-4-hydroxy-3,4-dihydronaphthalen-1(2H)-one, from Didymella glomerata.
References
Ariantari N, Ancheeva E, Frank M, Stuhldreier F et al. 2020 – Didymellanosine, a new decahydrofluorene analogue, and ascolactone C from Didymella sp. IEA-3B.1, an endophyte of Terminalia catappa. RSC Advances 10, 7232–7240.
Aveskamp MM, de Gruyter J, Woudenberg JHC, Verkley GJM, Crous PW. 2010 – Highlights of the Didymellaceae: a polyphasic approach to characterise Phoma and related pleosporalean genera. Studies in Mycology 65, 1–60.
Basim E, Basim H, Abdulai M, Baki D, Öztürk N. 2016 – Identification and characterization of Didymella bryoniae causing gummy stem blight disease of watermelon (Citrullus lanatus) in Turkey. Crop Protection 90, 150–156.
Besri M. 1982 – Survival and dissemination of Didymella lycopersici by tomato supports. Phytopathologische Zeitschrift 105, 1–10.
Chen Q, Hou LW, Duan WJ, Crous PW, Cai L. 2017 – Didymellaceae revisited. Studies in Mycology 87, 105–159.
Chen Q, Jiang JR, Zhang GZ, Cai L, Crous PW. 2015 – Resolving the Phoma enigma. Studies in Mycology 82, 137–217.
Chilvers MI, Rogers JD, Dugan FM, Stewart JE, Chen WD, Peever TL – 2009. Didymella pisi sp. nov., the teleomorph of Ascochyta pisi. Mycological Research 113, 391e400.
Cimmino A, Andolfi A, Fondevilla S, Abouzeid MA, Rubiales D, Evidente A. 2012 – Pinolide, a new nonenolide produced by Didymella pinodes, the causal agent of ascochyta blight on Pisum sativum. Journal of Agricultural and Food Chemistry 60, 5273–8.
De Gruyter J, Aveskamp MM, Woudenberg JHC, Verkley GJM et al. 2009 – Molecular phylogeny of Phoma and allied anamorph genera: Towards a re-classification of the Phoma complex. Mycological Research 113, 508–519.
Jayasiri SC, Hyde KD, Jones EBG, Jeewon R et al. 2017 – Taxonomy and multigene phylogenetic evaluation of novel species in Boeremia and Epicoccum with new records of Ascochyta and Didymella (Didymellaceae). Mycosphere 8, 1080–1101.
Luo G, Chen S, Yu J, Yuan J, Zheng L, Liu L, Chen B, Li J. 2020 – Naphthalenones and Naphthols Isolated from the Saussurea laniceps Endophytic Fungus Didymella glomerata X223. Chemistry & Biodiversity 17, e2000315.
Sudisha J, Vasanth Kumar T, Niranjana SR, Shekar Shetty H. 2004 – First report of gummy stem blight caused by Didymella bryoniae on muskmelon (Cucumis melo) in India. Plant Pathology 53, 533–533.
Wang X, Yin Q, Jiang S, Wu X, Delu W, Song B, Zhuo C. 2019 – First Report of Didymella bellidis Causing Tea Leaf Spot in China. Plant Disease 104, 4.
Woudenberg JH, Aveskamp MM, de Gruyter J, Spiers AG, Crous PW. 2009 –Multiple Didymella teleomorphs are linked to the Phoma clematidina morphotype. Persoonia 22 56–62.
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