Plectosphaerella endophytica Z.F. Yu & X.Q. Yang, 2021

Yang, Xiao Qian, Ma, Shi Yun, Peng, Ze Xiang, Wang, Zhong Qiao, Qiao, Min & Yu, Zefen, 2021, Diversity of Plectosphaerella within aquatic plants from southwest China, with P. endophytica and P. sichuanensis spp. nov., MycoKeys 80, pp. 57-75 : 57

Plectosphaerella endophytica Z.F. Yu & X.Q. Yang sp. nov. Figure 3

Etymology.

Latin, Plectosphaerella endophytica meaning endophytic, growing within plant tissue.

Description.

Colony on CMA after 3 d, hyphae hyaline, smooth, septate, thin-walled, branched, 1.9-3.3 µm (x̄ = 2.6 μm, n = 10) wide. Conidiophores macronematous, mononematous, erect, straight or flexuous, smooth-walled, hyaline, unbranched or occasionally irregular branched, sometimes 1-2-septate. Conidiogenous cells phialides, subulate, integrated, terminal, determinate, hyaline, smooth-walled. Conidia solitary, acrogenous, broadly navicular to broadly fusiform, suboblong or ellipsoidal, 0-1-septate, usually constricted at septum, bi-guttulate, hyaline, smooth-walled, aseptate conidia abundant, 5-9.1 × 2.5-3.5 µm (x̄ = 7.8 × 3.1 µm, n = 30); septate conidia scarce, 8.8-10.1 × 3.7-4.6 µm (x̄ = 9.4 × 4.1 µm, n = 30), forming hyaline to white mucilaginous masses. Sexual morph and chlamydospores absent.

Culture characteristics.

Colonies on OA reaching 52 mm diameter, on PDA reaching 48 mm diameter and on CMA reaching 43 mm diameter in 14 d at 25 °C. On PDA, colonies white, dense, fluffy hyphae growth in the medium surface, outermost mycelia formed an annule, margin smooth and entire, sporulation abundant, reverse pale yellow to white.

Typification.

China, Yunnan Province, Kunming, The Dian Lake, 24°96'N, 102°66'E, 1886 m alt., isolated from Hydrilla verticillata (L.f.) Royle as an endophyte, 20 Jul. 2014, Z.F. Yu, YMF 1.04701 (Holotype), ex-type CCTCC AF 2021053.

Notes.

Although the phylogenetic analyses showed that our isolate Plectosphaerella endophytica is close to P. oratosquillae , the conidia of P. oratosquillae are aseptate, multi-guttulate ( Duc et al. 2009). Furthermore, P. endophytica is most similar to P. verschoorii Hern.-Restr. & Giraldo López in the septa of conidia; both species produce 0-1-septate conidia, and septate conidia are larger than aseptate conidia ( P. verschoorii : 1-septate conidia, 8-11.5 × 2-3 μm; aseptate conidia, 3-8.5 × 2-3 μm), but there are obvious difference in the shape of conidia, P. endophytica was deeply constricted at septa. Besides, the phialides of P. verschoorii are shorter (up to 14 μm) ( Giraldo et al. 2019).

Figures

Figure 3. Plectosphaerella endophytica (YMF 1.04701, holotype) A-C colony on OA, PDA and CMA after 14 d D-F conidiophores and Phialides G conidia. Scale bars: 1.35 cm (A-C), 10 µm (D-G).