Diaporthe quercicola Q. Yang, 2022

Cao, Lingxue, Luo, Dun, Lin, Wu, Yang, Qin & Deng, Xiaojun, 2022, Four new species of Diaporthe (Diaporthaceae, Diaporthales) from forest plants in China, MycoKeys 91, pp. 25-47 : 25

Diaporthe quercicola Q. Yang sp. nov.

Fig. 5

Diagnosis.

Distinguished from the phylogenetically closely-related species, D. biguttulata , by its filiform, eguttulate alpha conidia.

Etymology.

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

Description.

On PDA: Conidiomata pycnidial, 250-330 μm diam, globose, solitary or aggregated, deeply embedded in the medium, erumpent, single or clustered in groups of 3-5 pycnidia, coated with hyphae, cream to yellowish translucent conidial droplets exuded from the ostioles. Conidiophores reduced to conidiogenous cells. Conidiogenous cells hyaline, cylindrical, unbranched, straight, tapering towards the apex, (17-)20-26(-34.5) × 2.5-3.5 μm (n = 30), L/W = 6.5-9. Alpha conidia (6.5-)7-8.5(-9) × (1.5-)2-3 μm (n = 30), L/W = 3-4.5, aseptate, hyaline, fusiform, apex at both ends, eguttulate. Beta conidia hyaline, aseptate, filiform, straight or sinuous at one end, eguttulate, (21.5-)25.5-31(-33) × 1 µm (n = 30), L/W = 22.5-31.5.

Culture characters.

Colony at first white, becoming dark brown with age. Aerial mycelium white, dense, fluffy, with yellowish conidial drops exuding from the ostioles after 20 days.

Specimens examined.

China. Shaanxi Province: Xian City , on branches of Quercus aliena , 10 July 2020, Q. Yang (holotype CSUFTCC104; ex-type living culture: CSUFTCC104; living cultures: CSUFTCC105 and CSUFTCC106) .

Notes.

Three strains representing Diaporthe quercicola cluster in a well-supported clade (ML/BI = 100/1), and appear closely related to D. biguttulata . Diaporthe quercicola can be distinguished based on ITS, his3, and tef-1α loci from D. biguttulata (8/461 in ITS, 18/448 in his3, and 22/325 in tef-1α). Morphologically, D. quercicola can be distinguished from D. biguttulata by its fusiform, eguttulate alpha conidia and narrower beta conidia (1 vs. 0.9-1.6 μm) ( Huang et al. 2015).

Figures

Figure 5. Diaporthe quercicola (CSUFTCC 104) a conidiomata formed on PDA b conidiogenous cells c alpha and beta conidia. Scale bars: 200 μm (a); 10 μm (b, c).