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Phylogenetic analysis of Plectosphaerella species based on multi-locus DNA sequences and description of P. sinensis sp. nov.

Su, Lei, Deng, Hui, Niu, Yong-Chun
Mycological progress 2017 v.16 no.8 pp. 823-829
Citrullus lanatus, Cucumis melo, Cucurbita moschata, Plectosphaerellaceae, chlamydospores, conidia, endophytes, fungi, internal transcribed spacers, new species, pathogens, phylogeny, ribosomal DNA, stems, China
Species in Plectosphaerella are well known as pathogens of several plant species causing fruit, root and collar rot and collapse. In an investigation of endophytic fungi associated with cucurbit plants in China, we isolated 77 strains belonging to the genus Plectosphaerella. To identify the isolated strains, we collected the type or reference strains of all currently accepted species in Plectosphaerella except P. oratosquillae and conducted a phylogenetic analysis. Phylogenetic analysis of the partial 28S rDNA sequences showed that all species in Plectosphaerella were located in one clade of Plectosphaerellaceae. Based on multi-locus phylogenetic analysis of the ITS, CaM, EF1, TUB and morphological characteristics, all species in Plectosphaerella were well separated. Three endophytic strains from stems of Cucurbita moschata, Citrullus lanatus and Cucumis melo from North China were assigned to a new species described as P. sinensis in this paper. The new species differs morphologically from other Plectosphaerella species by irregular chlamydospores, and the dimensions of phialides and conidia. The other endophytic strains from several cucurbit plants were identified as P. cucumerina.