云南黄馨叶斑病病原鉴定及其生物学特性

打开文本图片集

中图分类号：S436.8 文献标识码：A

Abstract： The pathogen causing leaf spot disease of Jasminum mesnyi in Hubei Province were isolated and purified，folowed by pathogenicity tests， morphological identification， molecular biological identification， and exploration of biological characteristics. Inoculation with the purified strain X-1 induced identical leaf symptoms on Jasminum mesnyi Hance within 7 days，confirming it as the causal fungus of the leaf spot disease.On PDA medium，the colony exhibited fluffy aerial hyphae with a raised grayish-brown center， and white mycelia at the margins.The reverse side of colonies showed an olive green to light brown central region. Microscopic examination revealed that strain X-1 produced brown conidiophores and conidia. Conidiophores were erect and slender，occurring singly or in clusters . Conidia of the strain were solitary or catenate，inverted rod-shaped or cylindrical，with 2-12 pseudosepta，measuring 15-163μm×5- 15μm . Based on morphological characteristics，it was preliminarily identified as a fungus of the genus Corynespora （Corynespora sp.）. Molecular analysis of rDNA ITS sequences and BLAST alignment showed that the strain X-1 was wellclustered with the Corynespora cassicola with a similarity as high as 99% ， while having a distant relationship with other species of the genus Corynespora. Thus，the pathogen was identified as C . cassiicola. This is the first report of C . cassiicola-induced leaf spot disease on Jasminum mesnyi in Hubei Province. The results of biological characteristics of strain X-1 showed that the optimum temperature for hyphal growth was 28∘C ，the optimal pH range was 6-9，and the best light condition was 12h/12h light-dark alternation. Additionally， the optimal carbon source for strain X-1 was sucrose，and the optimal nitrogen source was sodium nitrate.

Key words： Jasminum mesnyi Hance;leaf spot; pathogen identification; Corynespora cassiicola ; biological characteristics

云南黄馨（Jasminum mesnyi Hance）又名云南黄素馨、野迎春、迎春柳、南迎春，属于木犀科（Oleaceae）素馨属（Jasminum）常绿灌木，与迎春花（Jasminum nudiflorumLindl.）相似。（剩余10927字）