Microdochium yunnanense S.T. Huang, J.W. Xia, X.G. Zhang, W.X. Sun & Z. Li, 2020

Huang, Shengting, Xia, Jiwen, Zhang, Xiuguo, Sun, Wenxiu & Li, Zhuang, 2020, Two new species of Microdochium from Indocalamus longiauritus in south-western China, MycoKeys 72, pp. 93-108 : 93

Microdochium yunnanense S.T. Huang, J.W. Xia, X.G. Zhang, W.X. Sun & Z. Li sp. nov. Figure 3

Etymology.

Named after Yunnan Province, where the fungus was collected.

Diagnosis.

Characterised by conidiomata sporodochium-like and the size of conidia.

Type.

China, Yunnan Province: Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, on diseased leaves of Indocalamus longiauritus . 16 April 2019, S.T. Huang, HSAUP1011 holotype, ex-type living culture SAUCC1011.

Description.

Colonies on PDA attaining 48.0-61.5 mm in diameter after 15 days, felty, compact, erose or dentate, initially white, then becoming yellowish with age. Mycelium superficial, consisting of hyaline, smooth, branched, septate, 1.0-2.5 μm wide hyphae. Conidiomata sporodochium-like, appeared within 15 days or longer, formed in aerial mycelium or on agar surface, slimy, hyaline or orange, semi-submerged. Exudate occasionally appeared on old sporodochia. Reverse colorless to yellowish, due to the soluble pigment secreted. Conidiophores formed terminal or lateral with sympodial proliferation, solitary or aggregated. Most conidiophores tightly aggregated in a sporodochium, inconspicuous flat-tipped loci, irregularly branched, or borne directly on mycelial hyphae, straight or slightly curved, aseptate, guttulate, smooth-walled, apex subobtuse, base truncate. Conidiogenous cells of two types: some polyblastic, ampulliform, lageniform, with percurrent proliferations, 6.5-10.0 × 2.5-3.4 μm, neck up to 4.5 μm long, 1.0-1.5 μm wide, others straight or bent, smooth, cylindrical up to 10.0-11.5 μm long, 1.0-2.0 μm wide. Conidia aseptate, mostly lunate, a few ellipsoid and cylindrical, hyaline, straight or curved, obtuse, 0-2 guttulate in mature conidia, 6.8-10.0 × 2.4-3.5 μm. Chlamydospores was not observed. Sexual morph: unknown.

Culture characteristics.

Colonies on OA 58.1-61.5 mm in diameter after 15 days, entire, flat, white, lobate and radially margin, aerial mycelia cottony or sparse. Less exudate. Reverse white. Vegetative hyphae hyaline, abundant, branched, septate, thin-walled. Colonies on MEA 39.5-48.2 mm in diameter after 15 days, dense, initially white, becoming pale yellow, the centre of aerial mycelium cottony, periphery with scarce aerial mycelium, aerial mycelium formed a protuberance at center of colony.

Habitat and distribution.

Isolated from leaves of Indocalamus longiauritus in China.

Additional specimens examined.

China, Yunnan Province: Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, on diseased leaves of Indocalamus longiauritus . 16 April 2019, S.T. Huang, HSAUP1012, HSAUP1015, and HSAUP1018 paratype; living culture SAUCC1012, SAUCC1015, and SAUCC1018.

Notes.

Strains SAUCC1011, SAUCC1012, SAUCC1015, and SAUCC1018 belong to a single species as they have similar morphological features including culture characteristics, sporodochium, and conidia, the nearly identical sequence data, and cluster in a separate branch with a good support (ML-BS: 100% and BYPP: 1.00). The species is most phylogenetically close to M. bolleyi , and their branch lengths are slightly different. Nevertheless, the morphology of M. yunnanense and M. bolleyi ( Hong et al. 2008) are different in having sporodochium-like conidiomata, conidiogenous cells, and conidia. Microdochium yunnanense produced some sporodochium-like conidiomata, slimy, hyaline or orange, semi-submerged on the agar surface, with most conidial droplets formed on it and a few formed laterally along with hyaline hyphal cells. However, the conidia of M. bolleyi only formed laterally along with hyaline hyphal cells. They all produced two types of conidiogenous cells, cylindrical and ampulliform, but the size of M. yunnanense (10.0-11.5 × 1.0-2.0 μm (average 10.7 × 1.6 µm) and 6.5-10.0 × 2.5-3.4 μm (average 8.4 × 2.9 µm)), M. bolleyi (1.5-2.7 × 0.8-1.4 µm (average 2.1 × 1.0 µm) and 3.1-6.4 × 2.5-3.8 µm (average 4.9 × 3.2 µm)) were clearly different. Conidial shape was differed little, but the conidial size of M. yunnanense (6.8-10.0 × 2.4-3.5μm (average 8.3 × 3.1 µm)) has much larger than M. bolleyi (5.0-8.7 × 1.6-2.3 µm (average 6.4 × 1.9 µm)).

Figures

Figure 3. Microdochium yunnanense (SAUCC 1011) a leaves of host plant b sporodochia on media surface c-e surface of colony after 15 days on PDA (c), OA (d), MEA (e) f-h reverse of colony after 15 days on PDA (f), OA (g), MEA (h) i sporodochial conidiophores and conidiogenous cells with conidia j conidiogenous cells k-l conidia. Scale bars: 10 μm (i-l).