Taxonomy And Diversity Of Zygophiala, Scleroramularia, Cyphellophora And Other Genera Causing Sooty Blotch And Flyspeck

Sooty blotch and flyspeck(SBFS) is a fungal disease complex occurres on moist climate regions worldwidely. It colonizes and blemishes the epicuticularwax layer of a wide range of hosts, resulting smudges on fruits and reduces the aesthetic and economic value of fruit, bringing economic loss to the farmers.The causal agents of SBFS are highly diverse, including tens of genera in Ascomycota and Basidiomycota. The Fungal Lab has already accumulated isolates of SBFS-related genera: Zygophiala,Cyphellophora and Scleroramularia, and we also isolated SBFS isolates during the surveys in Guangdong, Hainan and Guangxi Province in 2011–2013. According to morphology and phylogeny analysis, these isolates were identified and their diversities were also studied.For the genus of Zygophiala,it is the first time that four genes of internal transcribed spacer(ITS), partial translation elongation factor 1-alpha(TEF), b-tubulin(TUB2), and actin(ACT) were construct—bothindividually and in combination—for analysis. There are nine species of Zygophiala in China of which five were new: Z. emperorae, Z. trispora, Z. musae, Z. inaequalisand Z. longspora. We also established a new combination, Z. pomi.The criteria for distinguishing different species among Zygophiala were also amended. Additional morphology characters, the hilum size, the size of “S”-shape conidiophore stipe, the number of scars on polyblastic conidiogenous cells were added in addition to conidiophore size, apical cell size, conidiogenesis cell size, number of hilum and conidia size.The genus of Cyphellophora was also analyzed by ITS and ITS-LSU-TUB2-RPB1 matrix and three new species—C. phyllostachysdis, C. artocarpi and C. musae—were delimited and described. The 2D structions of ITS1 and ITS2 of these three new species were distinguishable. The 2D structions of ITS1 and ITS2 are helpful for taxonomy identification.The genus of Scleroramularia was also studied. 10 species can be found in our country and four were new species: S. musae, S.pauciseptata, S. sanyaensis and S. vermispora.We also identified isolates in Ochroconis, Ramichloridium, Zasmidiumand Peltaster. Five new species were described: Ochroconissymmetrica, Ramichloridiumguangxiensis, R. nanensis, Peltaster micro and Zasmidium dimorphea.Zygophiala is highly diverse within species and host. There are 12 species of Zygophialaworldwide, of which 9 species can be found in China, 6 species can only be found in China. Z. wisconsinensisand Z. emperorae are the two predominant species in Chian,while Schizothyrium pomi, the predominant species in the USA and Europe areas has not been found in China. The host range of Zygophiala also expanded from Rosaceae plants like apple, hawthorn,plum to hawthorn, sweet persimmon, pawpaw and Japanese banana.Scanning electronmicroscope was used to monitor stages in the formationof sclerotium-like bodies on the wax surface, as well asramifications from these structures to form secondarysclerotium-like bodies. At a mature stage in the formation of sclerotium-like bodies, the matrix of hyphae,conidiophores, and conidia between these bodies collapsed, resulting in formation of the independent clustersof typical colonies of species in the flyspeck mycelialtype. Formation of conidiophores and secondary conidiain situ were also described for the first time for anyflyspeck species. Observation of conidiophores on naturally and artificially inoculated apple peels with lightmicroscope raises the possibility that formation of secondary conidia may be an important means of spatialdispersion of Z. wisconsinensis in apple orchards and theconidia might function in secondary spread.We collected SBFS fungal in Guangdong, Hainan and Guangxi Province systematically.We collected 817 Japanese banana specimens and isolated 307 isolates, including153 sporulated isolates. Scleroramularia was the dominant genusaccounted for 26.1%followed by Peltaster(about 20.9%). Zygophiala and Cyphellophora were rarely found, only take up 3%. Although Zygophiala was not dominant genus in Japanese banana, its distribution was widespread in China. Its hosts were also diverse except Japanese banana.