Diplodia pistaciicola L.W. Li & Jian K. Liu, 2023

Li, Wen-Li, Liang, Rui-Ru, Dissanayake, Asha J. & Liu, Jian-Kui, 2023, Botryosphaerialean fungi associated with woody oil plants cultivated in Sichuan Province, China, MycoKeys 97, pp. 71-116 : 71

Diplodia pistaciicola L.W. Li & Jian K. Liu sp. nov.

Fig. 10

Etymology.

The epithet ‘‘ pistaciicola ’’ refers to the host genus Pistacia , on which the holotype was collected.

Holotype.

HKAS 125890.

Description.

Saprobic on decaying branches of Pistacia chinensis . Sexual morph: Not observed. Asexual morph: Coelomycetous, Conidiomata 353-441 × 274.5-316 μm (x̄ = 397 × 295 μm, n = 10), immersed, forming split-like opening on the host, solitary or gregarious, globose to subglobose, dark brown to black, unilocular, papillate, ostiolate. Ostiole 38-49.5 μm diam., conical or circular, centrically located. Peridium 42-60 μm wide, composed of thick walled, dark brown to hyaline cells of textura angularis. Conidiophores reduced to conidiogenous cells. Conidiogenous cells 10-14 × 3-4 μm (x̄ = 12 × 3.5 μm, n = 20), holoblastic, discrete, cylindrical, hyaline, smooth, indeterminate, arising from the inner cavity of the conidiomata. Conidia 24.5-27 × 11-13 μm (x̄ = 25.5 × 12 μm, n = 30), L/W ratio = 2.2, ellipsoid to obovoid, aseptate, hyaline, thick-walled, guttulate.

Culture characteristics.

Conidia germinate on PDA within 12 h. Colonies growing on PDA, reaching a diameter of 4 cm after five days at 25 °C, effuse, velvety, with entire to slightly undulate edge. The early stage of the colony is white, later turning dark olivaceous and dark gray in reverse.

Material examined.

China, Sichuan Province, Chengdu City, Pidu District , 30°49'27"N, 103°47'42"E, elevation 442 m, on dead branches of Pistacia chinensis ( Anacardiaceae ), 5th March 2021, W.L Li, 049 (HKAS 125890, holotype), ex-type living culture UESTCC 22.0070 = CGMCC 3.24156; ibid., 049B (HUEST 22.0072 isotype), ex-isotype living culture UESTCC 22.0071. Additional sequence: LSU: OQ164833 (CGMCC 3.24156) .

Notes.

Phylogenetic analyses showed that two strains of Diplodia pistaciicola isolated from Pistacia chinensis are distinct but closely related to Di. agrifolia (CBS 124.30). The comparison of ITS, tef1 and tub2 of these two species indicate 5 bp (502), 3bp (224), 9 bp (425) differances, respectively. Morphologically, Di. agrifolia differs from Di. pistaciicola in producing two to three times larger ascomata than that of Di. pistaciicola (721-836 vs. 274.5-316 μm) and possessing smaller conidia (27-36.5 × 14.5-17.8 μm vs. 24.5-27 × 11-13 μm). In addition, conidia of Di. pistaciicola are hyaline, aseptate, rarely becoming pale brown and uniseptate with age, whereas conidia of Di. agrifolia are mostly dark brown and uniseptate before discharge from pycnidia.

Figures

Figure 10. Diplodia pistaciicola (HKAS 125890, holotype) a-c appearance of conidiomata on natural substrate d, e vertical section of conidiomata / conidioma f ostiole g section of peridium h-l conidiogenous cells and developing conidia m-q hyaline aseptate conidia. Scale bars: 200 μm (d); 50 μm (e); 20 μm (f, g); 10 μm (h-q).