Diaporthe betulina C.M. Tian & Q. Yang

Yang, Qin, Fan, Xin-Lei, Guarnaccia, Vladimiro & Tian, Cheng-Ming, 2018, High diversity of Diaporthe species associated with dieback diseases in China, with twelve new species described, MycoKeys 39, pp. 97-149 : 97

Diaporthe betulina C.M. Tian & Q. Yang sp. nov. Figure 5

Diagnosis.

Diaporthe betulina can be distinguished from the phylogenetically closely related species D. betulae in smaller locule and wider alpha conidia.

Holotype.

CHINA. Heilongjiang Province: Yichun city, on symptomatic branches of Betula platyphylla , 27 July 2016, Q. Yang (holotype: BJFC-S1472; ex-type culture: CFCC 52562).

Etymology.

Named after the host genus on which it was collected, Betula .

Description.

Conidiomata pycnidial, conical, immersed in bark, scattered, erumpent through the bark surface, with a solitary undivided locule. Ectostromatic disc brown to black, one ostiole per disc, 290-645 μm diam. Ostiole medium black, up to the level of disc. Locule undivided, 670-905 μm diam. Conidiophores 12.5-17.5 × 1.5-2 μm, cylindrical, hyaline, phiailidic, branched, straight or slightly curved. Alpha conidia hyaline, aseptate, ellipsoidal to fusiform, 0-2-guttulate, sometimes acute at both ends, 8-10 × 2.5-3 μm (av. = 9 × 2.6 μm, n = 30). Beta conidia hyaline, aseptate, filiform, straight or hamate, eguttulate, base subtruncate, tapering towards one apex, 26-32.5 × 1 µm (av. = 30 × 1 µm, n = 30).

Culture characters.

Cultures incubated on PDA at 25 °C in darkness. Colony flat with white felty aerial mycelium, turning white to dark brown aerial mycelium, conidiomata irregularly distributed on the agar surface.

Additional specimens examined.

CHINA. Heilongjiang Province: Yichun city, on symptomatic branches of Betula albo-sinensis , 27 July 2016, Q. Yang, living culture CFCC 52560 (BJFC-S1473); on symptomatic branches of Betula costata , 27 July 2016, Q. Yang, living culture CFCC 52561 (BJFC-S1474).

Notes.

Diaporthe betulina was isolated from Betula spp. cankers in Heilongjiang Province. Three strains representing D. betulina cluster in a well-supported clade and appear most closely related to D. betulae , which was also isolated from Betula platyphylla in Sichuang Province ( Du et al. 2016). Diaporthe betulina can be distinguished based on ITS, his3, tef1 and tub2 loci from D. betulae (11/461 in ITS, 9/453 in his3, 12/336 in tef1 and 7/695 in tub2). Morphologically, D. betulina differs from D. betulae in smaller locule (470-945 vs. 600-1250 μm) and wider alpha conidia (3-4 vs. 2.5-3 μm) ( Du et al. 2016).