Diaporthe albosinensis C.M. Tian & Q. Yang, 2020

Yang, Qin, Jiang, Ning & Tian, Cheng-Ming, 2020, Three new Diaporthe species from Shaanxi Province, China, MycoKeys 67, pp. 1-18 : 1

Diaporthe albosinensis C.M. Tian & Q. Yang sp. nov. Fig. 2

Diagnosis.

Distinguished from D. fraxinicola in having shorter conidiophores and longer beta conidia.

Etymology.

Named after the host plant, Betula albosinensis , from which the holotype was collected.

Description.

Conidiomata pycnidial, conical, immersed in bark, solitary to aggregated, erumpent through the bark surface, with a solitary undivided locule. Ectostromatic disc yellowish to brown, one ostiole per disc. Ostiole medium black, up to the level of disc. Locule undivided, (280-)290-375(-380) μm diam. Conidiophores (6-)8.5-13(-14.5) × (1.5-)2-2.5 μm, hyaline, cylindrical, smooth, phialidic, unbranched, straight or slightly curved. Alpha conidia hyaline, aseptate, fusiform, 0-1-guttulate, (7-)8-10(-11) × 2.5-3 μm. Beta conidia hyaline, aseptate, filiform, straight or slightly curved, eguttulate, base subtruncate, tapering towards one apex, (24-)25.5-30(-32) × 1-1.5 µm.

Culture characters.

Cultures incubated on PDA at 25 °C in the dark. Colony originally flat with white felted aerial mycelium, becoming light brown due to pigment formation, conidiomata irregularly distributed over agar surface, with yellowish conidial drops exuding from the ostioles.

Specimens examined.

China. Shaanxi Province: Ningshan County, Huoditang Forest Farm, 33°28'25"N, 108°29'39"E, on branches of Betula albosinensis , 10 July 2018, N. Jiang (holotype BJFC-S1670; ex-type living culture: CFCC 53066; living culture: CFCC 53067).

Notes.

Two isolates, representing D. albosinensis , are retrieved in a well-supported clade (ML BS/BPP=100/1) and appear most closely related to D. fraxinicola (Fig. 1 ). Diaporthe albosinensis can be distinguished from D. fraxinicola , based on tef1 and tub2 loci (3/335 in tef1 and 19/429 in tub2). Morphologically, D. albosinensis differs from D. fraxinicola in having shorter conidiophores (8.5-13 vs. 10.5-17.5 μm) and longer beta conidia (25.5-30 vs. 19-29.5 μm) ( Yang et al. 2018).

Figures

Figure 1. Phylogram of Diaporthe resulting from a maximum likelihood analysis based on combined ITS, cal, his 3, tef 1 and tub 2. Numbers above the branches indicate ML bootstraps (left, ML BS ≥ 50 %) and Bayesian Posterior Probabilities (right, BPP ≥ 0.90). The tree is rooted with Diaporthella corylina. Isolates in current study are in blue. " - " indicates ML BS <50 % or BI PP <0.90.

Figure 2. Diaporthe albosinensis on Betula albosinensis (BJFC-S 1670). A Habit of conidiomata in wood B transverse section of conidiomata C longitudinal section through conidiomata D conidiogenous cells attached with beta conidia E conidiogenous cells attached with alpha conidia F beta conidia. Scale bars: 200 μm (B-C); 20 μm (D, F); 10 μm (E).