云南墨兰炭疽病的病原菌鉴定、致病性及生物学特性研究

Pathogen Identification,Pathogenicity and Biological Characters of Anthracnose on Cymbidium sinense in Yunnan

【目的】确定云南屏边墨兰炭疽病的病原菌及其分类学地位、致病谱、生物学特性,为野生墨兰的保护提供理论依据。【方法】采用组织分离法、刺伤接种、形态学结合分子生物学确定墨兰炭疽病的病原菌分类学地位、致病谱,采用生长速率法、血球计数板法测试碳氮源、温度、pH值、光照等对因素对病原菌菌丝生长、产孢的影响。【结果】本试验分离鉴定了云南屏边的2株墨兰炭疽病分离物,经形态学特征、回接发病特征及基于ITS rDNA的系统发育分析鉴定为胶孢炭疽菌。该菌还能侵染兜兰、建兰、红柱兰,菌丝生长最佳碳氮源为甘露醇、甘氨酸,最适温度为30℃,致死温度为55℃,最适pH值为8,最适光照为暗培养;产孢最适碳氮源分别为麦芽糖、蛋白胨,最适温度35℃,致死温度60℃,最适pH值为7,光照对产孢影响不显著。【结论】云南屏边野生墨兰炭疽病的病原菌为胶孢炭疽菌,对兜兰、建兰、红柱兰致病,病原菌的环境适应性强,屏边大围山自然保护区应禁止栽培兜兰、建兰、红柱兰。

[ Objective] The pathogen of anthracnose on Cymbidium sinense from Pingbian County, Yunnan and its taxonomic status, patho- genic spectrum, biological characteristics were detected, which would lay foundation to protect wild C. sinense. [ Method] Tissue isolation, wounding inoculation, morphological and molecular characteristics were used to detect taxonomic status and pathogenic spectrum the pathogen of anthracnose on C. sinense. In additional, the effects of carbon sources, nitrogen sources, temperature, pH value, light on mycelial growth and conidial production were done by growth rate method and hemocytometer measurement. [ Result]Two isolates of anthracnose on Cymbidi-um sinense from Pingbian, Yunnan province were identified as Colletotrichum gloeosporioides by morphological characteristics, symptoms of re-inoculated on C. sinense and phylogenetic anal- ysis based on ITS rDNA regions. In addition, the pathogen could also infect the leaves of Cypripedium corrugatum, C. en- sifolium and C. wenshanense. The most suitable carbon and ni- trogen source for mycelia growth were mannitol and glycine re- spectively, the most suitable temperature was 30 ℃, the lethaltemperature was 55 ℃, the most suitable pH value was 8, and the most suitable light was dark. The most suitable carbon and nitrogen source for reproduction spore were maltose and peptone respectively, the most suitable temperature was 35 ℃, the lethal temperature was 60 ℃, the most suitable pH value was 7, light didn＇t affect the reproduction of spore. [ Conclusion] The pathogen of anthracnose on Cymbidi- um sinense from Pingbian county, Yunnan was Co. gloeosporioides, which also infected Cypripedium corrugatum Franch. , C. ensifolium （L.） Sw. , C. wenshanense Y. S. Wu et F. Y. Liu, was well-adapted enviroment. Thus, Cyp. corrugatum, C. ensifolium, C, wens- hanense should be forbidden to cultivate in Daweishan Mountain in Pingbian County.