Cytospora albodisca M. Pan & X.L. Fan, Front. Plant Sci. 12 (636460): 3 (2021).

Jia, Aoli, Chen, Baoyue, Lu, Hongyan, Xing, Yu, Li, Bin & Fan, Xinlei, 2024, Multigene phylogeny and morphology reveal three new species of Cytospora isolated from diseased plant branches in Fengtai District, Beijing, China, MycoKeys 101, pp. 163-189 : 163

Cytospora albodisca M. Pan & X.L. Fan, Front. Plant Sci. 12 (636460): 3 (2021).

Fig. 4

Description.

Sexual morph: not observed. Asexual morph: Conidiomata pycnidial, semi-immersed in the bark, scattered, producing black area on bark, circular to ovoid, with multiple locules, occasionally slightly erumpent through the surface. Conceptacle absent. Ectostromatic disc conspicuous, black, discoid, circular to ovoid, 680-1200 µm in diam., producing one ostiole per disc when mature. Ostiole grey to black, in the centre of the disc, 140-300 µm in diam. Locules numerous, subdivided frequently by invaginations with common walls, circular to ovoid, 500-1200 µm in diam. Conidiophores hyaline, unbranched, approximately cylindrical, 7-11 × 0.8-2 (av. = 9 ± 2.2 × 1.3 ± 0.3, n = 50) µm. Conidiogenous cells enteroblastic, phialidic. Conidia hyaline, elongate-allantoid, smooth, aseptate, 5-7 × 1-2 (av. = 6 ± 0.5 × 1.5 ± 0.3, n = 50) µm.

Culture characteristics.

Cultures on PDA are initially white, growing fast up to 5 cm in diam. after 3 d and entirely covering the 6 cm Petri dish after 5 d, becoming dark herbage green to dull green after 7-10 d. Colonies are sparse in the centre and compact to the margin. After 30 d, pycnidia distributed irregularly on surface.

Materials examined.

China, Beijing City, Fengtai Distinct, Qianling Mountain scenic area, 39°51'12.28"N, 116°5'17.74"E, from branches of Malus x micromalus , 12 Apr 2023, A.L. Jia & X.L. Fan (BJFC CF20230401, living culture CFCC 59467); Qianling Mountain scenic area, 39°51'12.28"N, 116°5'17.74"E, from branches of Euonymus japonicus , 12 Apr 2023, A.L. Jia & X.L. Fan (BJFC CF20230402, living culture CFCC 59537) .

Notes.

Cytospora albodisca was described by Pan et al. (2021) associated with canker disease of Platycladus orientalis in China. It can be identified by having ascostroma surrounded by a black conceptacle, producing allantoid, aseptate ascospores (8-14 × 2-3.5 µm). In this study, the asexual morph of Cytospora albodisca is characterised by the pycnidial stromata submerged in the cortex with multiple locules, filamentous conidiophores producing hyaline, allantoid, eguttulate and smooth conidia. Phylogenetically, the isolates (CFCC 59459 and 59537) clustered together with C. albodisca with high statistical support (ML/BI = 100/1) (Fig. 2 ). Therefore, the isolate in this study was confirmed to be C. albodisca .

Figures

Figure 2. Phylogram of Cytospora based on Maximum Likelihood (ML) analysis of the dataset of combined ITS, act, rpb 2, tef 1 - a and tub 2 genes. Numbers above the branches indicate ML bootstrap values (ML-BS ≥ 60 %) and Bayesian Posterior Probabilities (BPP ≥ 0.9). Ex-type isolates are in bold. lsolates in this study marked with its hosts and highlighted in two different colours where the novel species are shown in dark blue and the known species are shown in light blue.

Figure 4. Cytospora albodisca from Euonymus japonicus (BJFC CF 20230402) A, B habit of conidiomata on branch C transverse section through conidiomata D longitudinal section through conidiomata E conidiophores and conidiogenous cells F conidia. Scale bars: 2 mm (A); 1 mm (B); 500 µm (C); 200 µm (D); 10 µm (E, F).