Cytospora sibiraeicola Ning Jiang, 2024

Li, Jiangrong, Li, Jieting & Jiang, Ning, 2024, Morphology and phylogeny of Cytospora (Cytosporaceae, Diaporthales) species associated with plant cankers in Tibet, China, MycoKeys 104, pp. 51-70 : 51

Cytospora sibiraeicola Ning Jiang sp. nov.

Fig. 4

Etymology.

" sibiraei " refers to the host genus Sibiraea and "- cola " means inhabiting.

Holotype.

CAF800084.

Description.

Associated with branch canker disease of Sibiraea angustata . Sexual morph: Undetermined. Asexual morph: Pycnidial stromata ostiolated, immersed or semi-immersed in the host bark, scattered, discoid, with multiple locules. Conceptacle black, circular surrounded stromata. Ectostromatic disc black, circular to ovoid, (200-)300-450(-500) μm diam., with one ostiole per disc. Ostioles dark, at the same level as the disc, (30-)60-80(-95) μm diam. Locule numerous, arranged circularly or elliptically with independent walls, (200-)250-380(-500) μm diam. Peridium comprising few layers of cells of textura angularis, with innermost layer brown, outer layer brown to dark brown. Conidiophores hyaline, unbranched, thin-walled, filamentous. Conidiogenous cells enteroblastic polyphialidic, 12.5-32.5 × 2-3.5 μm. Conidia hyaline, allantoid, smooth, aseptate, thin-walled, (3.3-)3.4-4.3(-4.5) × 1.2-1.6 μm (x̄ = 3.9 × 1.5 μm).

Culture characteristics.

Colonies on PDA flat, with flocculent aerial mycelium and undulate margin, initially white, becoming olivaceous grey and reaching 90 mm diameter after 10 days at 25 °C, sterile.

Materials examined.

China, Tibet Tibetan Autonomous Region, Lhasa City , Mozhugongka County, Riduo Township , Zen Village , on cankered branches of Sibiraea angustata , 28 July 2022, Jin Peng, Liu Yuanyuan, Jiang Ning and Liu Min (CAF800083, holotype); ex-type cultures CFCC 59100 and CFCC 59101 .

Notes.

Cytospora sibiraeicola is phylogenetically close to C. phialidica and C. viticola (Fig. 1 ). Morphologically, C. sibiraeicola (3.4-4.3 × 1.2-1.6 μm) and C. phialidica (3.5-5 × 1-2 μm) have much shorter conidia than C. viticola (5.2-7 × 0.9-1.6 μm) ( Lawrence et al. 2017; Li et al. 2020). In addition, these three species can be distinguished by the host and distribution ( C. sibiraeicola from Sibiraea angustata in China vs. C. phialidica from Alnus glutinosa in Italy vs. C. viticola from Vitis vinifera in the USA) ( Lawrence et al. 2017; Li et al. 2020).

Figures

Figure 1. Maximum Likelihood tree generated from combined ITS, act, rpb 2, tef 1 and tub 2 sequence data. Bootstrap support values ≥ 50 % and Bayesian posterior probabilities ≥ 0.90 are demonstrated at the branches. Ex-type cultures are marked with (*).

Figure 4. Cytospora sibiraeicola (CAF 800084, holotype) A, B canker disease symptom C conidioma D transverse section through a conidioma E longitudinal section through a conidioma F conidiophores and conidia G, H conidia. Scale bars: 2000 µm (B); 1000 µm (C-E); 10 µm (F-H).