Diaporthe celticola C.M. Tian & 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 celticola C.M. Tian & Q. Yang sp. nov.

Fig. 2

Diagnosis.

Distinguished from the other Diaporthe species based on DNA sequence data and characterised by conidiomata with single necks erumpent through the host bark.

Etymology.

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

Description.

Conidiomata pycnidial, 535-605 × 210-225 μm diam, solitary and with single necks erumpent through host bark. Ectostromatic disc brown, one ostiole per disc, with yellowish cream conidial drops exuding from the ostioles. Tissue around the neck is cylindrical. Locule circular, undivided, 350-375 μm diam. Conidiophores reduced to conidiogenous cells. Conidiogenous cells unbranched, straight or sinuous, apical or base sometimes swelling, (8-)10.5-13(-14.5) × 1-1.5 μm (n = 30), L/W = 8.5-10.5. Alpha conidia hyaline, aseptate, ellipsoidal, biguttulate, (5-)6-7 × 3.5-4 μm (n = 30), L/W = 1.5-1.8. Beta conidia not observed.

Culture characters.

Colony originally flat with white fluffy aerial mycelium, becoming light brown to olive-green mycelium with age, marginal area irregularly, with yellowish cream conidial drops exuding from the ostioles.

Specimens examined.

China, Zhejiang Province: Hanzhou City , on branches of Celtis vandervoetiana , 12 May 2018, Q. Yang & Y.M. Liang (holotype BJFC-S1616; ex-type living culture: CFCC 53074; living cultures: CFCC 53075 and CFCC 53076) .

Notes.

Three strains representing Diaporthe celticola cluster in a well-supported clade (ML/BI = 100/1), and appear closely related to D. acaciigena . Diaporthe celticola can be distinguished based on ITS, cal, his3, tef-1α, and tub2 loci from D. acaciigena (29/473 in ITS, 68/442 in cal, 53/460 in his3, 79/330 in tef-1α, and 49/415 in tub2). Morphologically, D. celticola is characterised by conidiomata with single necks erumpent through the host bark and can be distinguished from D. acaciigena by smaller alpha conidia (6-7 × 3.5-4 vs. 10-11 × 6-6.5 μm) ( Crous et al. 2011). This is the first occasion that Diaporthe species have been discovered from infected branches on Celtis vandervoetiana and demonstrates it to be a new species based on phylogeny and morphology.

Figures

Figure 2. Diaporthe celticola (BJFC-S 1616) a, b habit of conidiomata on twig c transverse section through conidiomata d, e conidiogenous cells with alpha conidia f alpha conidia g, h conidiomata formed on PDA. Scale bars: 200 μm (b, c); 10 μm (d-f).