Helminthosporium sinensis Jing W. Liu & Jian Ma, 2022

Liu, Jingwen, Hu, Yafen, Luo, Xingxing, Castaneda-Ruiz, Rafael F. & Ma, Jian, 2022, Three novel species of Helminthosporium (Massarinaceae, Pleosporales) from China, MycoKeys 94, pp. 73-89 : 73

Helminthosporium sinensis Jing W. Liu & Jian Ma sp. nov.

Fig. 3

Etymology.

Referring to the country in which the fungus was collected.

Holotypus.

HJAUP M2121.

Description.

Saprobic on dead branches. Sexual morph: Undetermined. Asexual morph: Hyphomycetous. Colonies on natural substrate effuse, scattered, hairy, brown to black. Mycelium partly superficial, partly immersed in the substratum, composed of branched, septate, pale brown to brown, smooth hyphae. Conidiophores macronematous, mononematous, solitary or in groups of 2-4, simple, straight or flexuous, thick-walled, cylindrical, smooth, brown to dark brown, paler towards the apex, with well-defined small pores at the apex and rarely laterally beneath the upper 1-4 septa, 220-370 × 6-8.5 μm. Conidiogenous cells polytretic, integrated, terminal and intercalary, cylindrical, brown, smooth, with noncicatrized, distinct pores. Conidial secession schizolytic. Conidia acropleurogenous, solitary, rarely catenate, dry, obclavate, pale brown, 2-7-distoseptate, smooth, straight or curved, wider below than apex, truncate and dark at base, apically rostrate and pale, 37-60 μm long, 5.5-8.5 μm wide, tapering to 3-3.5 μm wide near the apex, 3-6 μm wide at the basal scar.

Cultural characteristics.

Colony on PDA reaching 30-37 mm diam. after 2 weeks in an incubator under dark conditions at 25 °C, pale brown, irregular circular, surface velvety, outermost layer gray; reverse dark brown, produces pale green pigment.

Material examined.

China, Yunnan Province: Xishuangbanna Dai Autonomous Prefecture, Menghai County, Mengsong Township , on dead branches of an unidentified broadleaf tree, 13 July 2021, J.W. Liu, HJAUP M2121 (Holotype), ex-type living culture HJAUP C2121 .

Notes.

Phylogenetic analysis shows that the strain of H. sinensis (HJAUP C2121) forms an independent clade, and clusters with the strains of H. nabanhensis (HJAUP C2054) and H. chlorophorae (BRIP 14521). The BLASTn analysis of ITS of our ex-type strain HJAUP C2121 showed 89% identity (536/602 bp, 17/602 gaps) with ex-type strain HJAUP C2054 of H. nabanhensis , and showed 91% identity (430/471 bp, 13/471 gaps) with ex-type strain BRIP 14521 of H. chlorophorae . Moreover, H. sinensis differs from H. nabanhensis by its longer and narrower conidia (37-60 × 5.5-8.5 μm vs. 26.5-46.5 × 6.5-10 μm), and smaller conidiophores (220-370 × 6-8.5 μm vs. 365-557 × 6.5-13.5 μm), and from H. chlorophorae by its smaller conidia (37-60 × 5.5-8.5 μm vs. 52-102 × 8-11 μm) and longer and narrower conidiophores (220-370 × 6-8.5 μm vs. 120-270 × 7-10 μm), and from H. guangxiense ( Zhang and Zhang 2009) in smaller conidiophores (220-370 × 6-8.5 μm vs. 330-850 × 14-25 μm) and smaller conidia (37-60 × 5.5-8.5 μm vs. 76-110 × 16-22 μm) with fewer septa (2-7 vs. 9-17). In addition, the conidia of H. sinensis are solitary or rarely catenate, whereas those of H. guangxiense , H. nabanhensis and H. chlorophorae are solitary.

Figures

Figure 3. Helminthosporium sinensis (HJAUPM 2121, holotype) A, B culture on PDA from above and reverse C conidia D, E conidiophores, conidiogenous cells and conidia F conidiophores.