Plectosphaerella guizhouensis Zhi.Y. Zhang, Y.F. Han & Z.Q. Liang

Zhang, Zhi-Yuan, Chen, Wan-Hao, Zou, Xiao, Han, Yan-Feng, Huang, Jian-Zhong, Liang, Zong-Qi & Deshmukh, Sunil K., 2019, Phylogeny and taxonomy of two new Plectosphaerella (Plectosphaerellaceae, Glomerellales) species from China, MycoKeys 57, pp. 47-60 : 47

Plectosphaerella guizhouensis Zhi.Y. Zhang, Y.F. Han & Z.Q. Liang sp. nov. Figure 2

Etymology.

Referring to Guizhou, the province where the isolate was collected.

Description.

Sexual morph not observed. Asexual morph on CA. Mycelium hyaline, smooth, septate, branched and thin-walled, 1-2 μm (x̄ =1.5 μm) wide. Conidiophores solitary, unbranched or rarely branched, hyaline, smooth, thin-walled, sometimes radiating out from hyphal coils. Conidiogenous cells growing from a short branch or directly from mycelia, phialides, discrete, polymorphic, cylindrical, sub-cylindrical or ampulliform; terminal or lateral, hyaline, smooth, solitary, straight at the apex, sometimes bent or helicoid, gradually tapering to the apex, 3.5-17 × 0.5-2 μm (x̄ = 9.5 × 1.5 μm, n = 20), collarette cylindrical, 0.5-1 μm deep. Conidia aggregating in slimy heads, non-septate or 1-septate, fusiform or cylindrical, sometimes rounded at both ends, hyaline, smooth, thin-walled; 2-6.5 × 1.5-5 μm (x̄ = 5.5 × 2 μm, n = 10) (1-septate), 3-5 × 1-1.5 μm (x̄ = 4 × 1.5 μm, n = 10) (non-septate). Chlamydospores absent.

Culture characteristics.

Colonies on PDA reaching 74-75 mm diam. in 14 d at 25 °C, milk white, flat, aerial hyphae sparse, floccose at periphery, sub-rounded, margin regular, reverse milk white. Colonies on CA reaching 65-67 mm diam. in 14 d at 25 °C, white to milk white, flat, floccose, margin weakly undulate to faintly fimbriate, reverse milk white.

Typification.

CHINA, Guizhou, Guiyang, Qianlingshan Park, 26°60'N, 106°69'E, 1210 m a.s.l., on soil, 10 Sep. 2016, collected and isolated by Zhi-Yuan Zhang, HMAS 255618 (holotype), ex-type CGMCC 3.19658 (= GZUIFR-QL9.9.1); ex-isotype CGMCC 3.19659 (= GZUIFR-QL9.9.2) and CGMCC 3.19660 (= GZUIFR-QL9.9.3).

Notes.

Based on multi-locus phylogenetic analyses ( Figure 1 , see Results) and similar morphological characteristics, the three strains are regarded as the same species, which cluster together very well and form a single clade separated from other species of Plectosphaerella ( Figure 1 ). Morphologically, Plectosphaerella guizhouensis differs from others species by the fusiform or cylindrical conidia, non-septate conidia (average 4 × 1.5 μm) and separate conidia (5.5 × 2 μm) (see Key). Therefore, based on combined phylogenetic and morphological evidence, P. guizhouensis is identified as a new species of Plectosphaerella .

Figures

Figure 1. Phylogenetic tree of Plectosphaerella species derived from Bayesian analyses and Maximum Likelihood analyses, based on the combined sequences dataset of LSU + ITS + EF 1 α + RPB 2. Bayesian posterior probabilities (BI pp) greater than 0.7 and Maximum Likelihood bootstrap support values (MLBS) greater than 95 % are shown above branches. New isolates are in bold and blue. The tree used Brunneochlamydosporium nepalense (CBS 277.89 and CBS 971.72) as outgroup.

Figure 2. Plectosphaerella guizhouensis (HMAS 255618, holotype). A-B The front and reverse of colony on CA after 14 d at 25 ° C C Septate and aseptate conidia D Hyphal coils E-N Phialides. Scale bars: 10 μm (C-N).