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

Fig. 4

Etymology.

Referring to Yunnan province, where the type specimen was collected.

Holotypus.

HJAUP M2071.

Description.

Saprobic on dead branches. Sexual morph: Undetermined. Asexual morph: Hyphomycetous. Colonies on natural substrate effuse, scattered, hairy, brown to dark brown. 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 one cylindrical, enteroblastic percurrent extension, and with well-defined small pores at the apex and rarely laterally beneath the upper 1-5 septa, 560-680 × 12.5-15.5 μm. Conidiogenous cells polytretic, integrated, terminal and intercalary, cylindrical, pale brown to brown, smooth, with noncicatrized, distinct pores. Conidial secession schizolytic. Conidia acropleurogenous, solitary, dry, obclavate, sigmoid, lunate or uncinate, pale brown, 4-7-distoseptate, smooth, straight or flexuous, wider below than apex, truncate and dark at base, apically rostrate and pale, 30.5-55.5 μm long, 9-11 μm wide, tapering to 2.5-3 μm near the apex, 3-7.5 μm wide at the basal scar.

Cultural characteristics.

Colony on PDA reaching 75-82 mm diam. after 2 weeks in an incubator under dark conditions at 25 °C, irregular circular, surface velvety, with brown and denser mycelium at the center, becoming white and sparser towards the edge; reverse pale brown at the center, with little black dots.

Material examined.

China, Yunnan Province: Xishuangbanna Dai Autonomous Prefecture, Nabanhe National Nature Reserve , on dead branches of an unidentified broadleaf tree, 12 July 2021, J.W. Liu, HJAUP M2071 (Holotype), ex-type living culture HJAUP C2071 .

Notes.

Phylogenetic analysis shows that the strain of H. yunnanensis (HJAUP C2071) clustered together and formed a sister clade with three different strains of H. austriacum (L132, L137, L169) ( Voglmayr and Jaklitsch 2017). The BLASTn analysis of H. yunnanensis (HJAUP C2071) and H. austriacum (L132HT) shows 97% identity (524/541, 4 gaps) using ITS, 99% identity (550/553, 2 gaps) using LSU, 99% identity (872/873, 1 gap) using SSU, 98% identity (738/752, no gap) using TEF1, and 98% identity (1077/1095, no gap) using RPB2. Helminthosporium yunnanensis morphologically differs from H. austriacum in wider conidiophores (560-680 × 12.5-15.5 μm vs. 275-700 × 7-11 μm) with one cylindrical, enteroblastic percurrent extension, and narrower conidia (30.5-55.5 × 9-11 μm vs. 35-48 × 13.7-16.5 μm), and from H. obpyriforme ( Zhang and Zhang 2009) in bigger conidiophores (560-680 × 12.5-15.5 μm vs. 225-460 × 9.5-13 μm) and smaller conidia (30.5-55.5 × 9-11 μm vs. 47-74 × 14-19 μm) with fewer septa (4-7 vs. 5-9).

Figures

Figure 4. Helminthosporium yunnanensis (HJAUPM 2071, holotype) A, B culture on PDA from above and reverse C conidiophores with conidia D conidiogenous cells and conidia E conidia.