Cytospora sorbariae A.L. Jia & X.L. Fan, 2024

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 sorbariae A.L. Jia & X.L. Fan sp. nov.

Fig. 9

Etymology.

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

Typification.

China. Beijing City, Fengtai District, Beijing Garden Expo, 39°52'35.65"N, 116°11'4.02"E, from branches of Sorbaria sorbifolia , 7 Apr 2023, A.L. Jia & X.L. Fan (holotype BJFC CF20230417, ex-holotype living culture CFCC 59445); 39°52'35.43"N, 116°11'4.62"E, from branches of Sorbaria sorbifolia , 7 Apr.2023, A.L. Jia & X.L. Fan (paratype BJFC CF20230419, ex-paratype living culture CFCC 59529).

Description.

Sexual morph: not observed. Asexual morph: Conidiomata pycnidial immersed in the bark, scattered, erumpent through the surface of bark in a large area, with multiple locules. Conceptacle absent. Ectostromatic disc brown to black, circular to ovoid, erumpent through the surface of bark in a large area, conspicuous when mature, 160-300 µm in diam., with one or two ostioles per disc. Ostioles grey to black, at the same or slightly above the level of the disc surface, 50-85 µm in diam. Locules numerous, subdivided frequently by invaginations with common walls, circular to ovoid, 550-750 µm in diam. Conidiophores hyaline, unbranched, approximately cylindrical, 14-18 × 1-1.5 µm. Conidiogenous cells enteroblastic, phialidic. Conidia hyaline, elongate-allantoid, smooth, aseptate, 5.5-7.5 × 1.5-2.5 (av. = 6.5 ± 0.7 × 2 ± 0.3, n = 50) µm.

Culture characteristics.

Cultures on PDA are initially white, growing fast up to cover the 5.5 cm Petri dish after 3 d, becoming vinaceous buff after 7-10 d. Colonies are flat with a uniform texture, lacking aerial mycelium. Colony margin regular. After 30 d, pycnidia distributed irregularly on surface.

Additional materials examined.

China. Beijing City, Fengtai District , Beijing Garden Expo , 39°52'35.10"N, 116°11'4.31"E, from branches of Sorbaria sorbifolia , 7 Apr 2023, A.L. Jia & X.L. Fan (BJFC CF20230418, living culture 59443; BJFC CF20230420, living culture 59530) .

Notes.

Cytospora sorbariae is associated with canker disease of Sorbaria sorbifolia in the current study. It can be identified by having conidiomata with a column lenticular tissue in the centre and its distinct disc of stromata on branches. Additionally, the four strains are phylogenetically separated from all other available strains included in this study. The clear multi-gene phylogram placed it in a distinct clade with high support (ML/BI = 100/1, Fig. 2 ).

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 9. Cytospora sorbariae from Sorbaria sorbifolia (BJFC CF 20230417) A, B habit of conidiomata on branch C transverse section through conidiomata D longitudinal section through conidiomata E, F conidiophores and conidiogenous cells G conidia. Scale bars: 1 mm (A); 100 µm (B-D); 10 µm (E-G).