New Species of Didymellaceae within Aquatic Plants from Southwestern China

Abstract

Members of Didymellaceae have a wide geographical distribution throughout different ecosystems, and most species are associated with fruit, leaf, stem and root diseases of land plants. However, species that occur in aquatic plants are not clearly known. During a survey of the diversity of endophytes in aquatic plants in Yunnan, Sichuan, and Guizhou provinces, we obtained 51 isolates belonging to Didymellaceae based on internal transcribed spacer region (ITS) sequences. Further, the phylogenetic positions of these isolates were determined by combined sequences composed of ITS, partial large subunit nrRNA gene (28S nrDNA; LSU), RNA polymerase II second largest subunit (rpb2) and partial beta-tubulin gene (tub2). Combining morphological characteristics and multi-locus phylogenetic analyses, two new varieties belong to Boeremia and 12 new species distributed into seven genera were recognized from 51 isolates, i.e., Cumuliphoma, Didymella, Dimorphoma, Ectophoma, Leptosphaerulina, Remotididymella, and Stagonosporopsis. Among these species, only one species of Stagonosporopsis and two species of Leptosphaerulina show teleomorphic stages on OA, but have no anamorphic state. Each new species is described in detail, and the differences between new species and their phylogenetically related species are discussed here. The high frequency of new species indicates that aquatic plants may be a special ecological niche which highly promotes species differentiation. At the same time, the frequent occurrence of new species may indicate the need for extensive investigation of fungal resources in those aquatic environments where fungal diversity may be underestimated.

Morphological and Phylogenetic Analyses Reveal Three New Species of Didymella (Didymellaceae, Pleosporales) from Jiangxi, China

“…Crous et al [15,16] introduced D. cari and D. finnmarkica using ITS, LSU, ACT, and TUB2 or RPB2. From 2020 onwards, except for D. nakii, D. azollae, and D. brevipilosa using ITS, LSU, and TUB2 orRPB2, the further described 27 Didymella species were introduced using ITS, LSU, RPB2, and TUB2 [4,7,[9][10][11]13,17,[19][20][21][22][24][25][26]. Recent studies indicated that the use of LSU, ITS, TUB2, and RPB2 shows good phylogenetic resolution in revealing the phylogeny of Didymella and related genera within Didymellaceae.…”

“…To date, studies conducted on Didymella have mainly focused on their alpha-taxonomy, and most species are considered to be saprobes or phytopathogens of woody and herbaceous hosts [4,9,13,28,42], whereas only a few species have been isolated from inorganic substrates, such as D. glomerata and D. pomorum from inorganic materials including asbestos, cement, paint, etc. [3,12,53].…”

“…Chen et al [3] further clarified the generic delimitation in Didymellaceae using a morpho-molecular approach; Didymella was restricted to a monophyletic group and encompassed 37 species. Since then, 49 further species were added based on morphological and phylogenetic analyses [4,7,[9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26], but D. acutilobae, D. erhaiensis, D. gongkaensis, D. hippuris, and D. myriophyllana were considered invalid species under the ICN Art. 40.8 or Art.…”

Ascochyta erotica sp. nov. Pathogenic on Convolvulus arvensis

“…According to the actual taxonomy of the Didymellaceae family, the identification of its members, especially Ascochyta species, should be based on the consolidated species concept (CSC), which relies on the integration of phylogenetic, morphological, and biological characters. Phylogenetic data should be obtained by genealogical concordant phylogenetic species recognition (GCPSR) using a multilocus phylogenetic analysis to identify fungal species [4,[6][7][8][9][10].…”