Cytospora berberidicola Yun Liu, 2023

Liu, Yun, Chi, Bao-Jie, Jiang, Ning, Yang, Xiang-Li & Liu, Jin, 2023, Cytospora berberidicola sp. nov. (Diaporthales, Cytosporaceae) in China, Phytotaxa 626 (2), pp. 101-109 : 103

Cytospora berberidicola Yun Liu , sp. nov. ( Fig. 2 )

MycoBank 848885

Etymology:— Named after the host genus Berberis , from which it was collected.

Type:— CHINA. Tibet: Lhasa, Laru wetland, 91.103°E, 29.683°N, 3615 m asl, on stems and branches of Berberis thunbergii var. atropurpurea, Yuanyuan Liu, Min Liu, Ning Jiang & Peng Jin , 28 July 2022, holotype CAF800082 ; ex-type living culture CFCC 58883 .

Symptoms present as circular or ovoid, dark brown, elevated and ruptured lesions on the branches.Asexual morph: Conidiomata pycnidial, immersed in bark, erumpent through the surface of bark when mature, discoid to conical, with single locules, 215–365 μm (n = 50) in diam. Conceptacle dark. Ectostromatic disc brown to dark, circular to ovoid, 155–320 μm (n = 50) in diam. Ostiole inconspicuous, circular to ovoid, brown to black at the same level as the disc surface. Locule undivided, circular to ovoid. Conidiophores hyaline, branched. Conidiogenous cells enteroblastic, phialidic, subcylindrical to cylindrical. Conidia hyaline, eguttulate, elongate-allantoid, aseptate, 6.5–9.5 × 1.0–2 μm (n = 50). Sexual morph: not observed.

Culture characteristics:— Cultures on PDA initially white, growing up to 7.0 cm after 3 days at 25 ° C, becoming pale yellow after 7 days. The colonies flat with a uniform texture, conidiomata randomly distributed on medium surface.

Additional material examined:— CHINA. Tibet: Lhasa, Laru wetland, 91.096°E, 29.686°N, 3643 m asl, on stems and branches of Berberis thunbergii var. atropurpurea, Ning Jiang , 29 July 2022 (collection number: SDAEU105 ) ; CHINA, Tibet, Lhasa, Laru wetland, 91.078°E, 29.691°N, 3607 m asl, on stems and branches of B. thunbergii var. atropurpurea, Ning Jiang , 29 July 2022 (collection number: SDAEU106 ) .

Notes:— Three isolates of Cytospora from cankered branches of Berberis thunbergii var. atropurpurea clustered into a well-supported clade distinguished from the other members within this genus ( Fig. 1 ). Phylogenetically, the new species, C. berberidicola clustered into C. tibetensis . However, these species can be distinguished by their hosts with C. tibetensis occurring on Cotoneaster sp. ( Pan et al. 2020). Cytospora berberidicola also has smaller conidiomata than C. tibetensis (215–365 μm vs. 585–650 μm), and longer conidia (6.5–9.5 × 1.0–2.0 μm vs. 5.0–5.5(–6.0) × 1.5–2.0 μm) ( Pan et al. 2020). Furthermore, the ectostromatic disc and disc of C. berberidicola are darker than C. tibetensis .

Figures

FIGURE 1. Phylogram constructed for Cytospora using a combined dataset of actin (ACT), internal transcribed spacer (ITS), RNA polymerase II second largest subunit (RPB2), translation elongation factor 1-alpha (TEF1) and beta-tubulin (TUB2) genes, based on the best-parsimonious tree. Maximum likelihood bootstrap support values above 70% are shown. The thickened branches indicate posterior probabilities greater than 0.95 obtained from BI. Scale bar = 0.2. Diaporthe vaccinii CBS 160.32 was used as the outgroup. Ex-type strains are in bold. Strains from the current study are in bold and blue.

FIGURE 2. Cytospora berberidicola from Berberis thunbergii var. atropurpurea (CAF800082). A–C. Habit of conidiomata on twig. D. Transverse section of conidioma. E. Longitudinal section through conidioma. F–H. Conidiophores and conidiogenous cells. I. Conidia. Scale bars: B–E=200 μm, F–I=10 μm.