陕西省大白菜主产区黑腐病菌致病型的研究

Pathogenesis division of black rot bacteria of Chinese cabbage in Shaanxi central productive area

【目的】了解陕西省大白菜主产区黑腐病菌致病型的分化情况,为大白菜抗病性鉴定和育种工作奠定基础,并为大白菜不同类型品种的合理布局提供依据。【方法】采集陕西渭南、泾阳、临潼和杨凌4个大白菜主产区的典型黑腐病病样,进行病菌分离、纯化及形态学特征和柯赫氏法则鉴定,获得有代表性的35个大白菜黑腐病菌株。在对各菌株进行革兰氏、夹膜、鞭毛染色检验以及淀粉水解能力和明胶液化程度测定的基础上,用7个不同抗性大白菜品种作为鉴别寄主,采用喷雾法进行交叉接种,对35个菌株的致病类型进行了划分,并对各致病类型的分布进行了统计。【结果】根据抗、感反应的一致性,将35个大白菜黑腐病菌株划分为Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ、Ⅵ6类致病型,其中Ⅲ型致病力最强,Ⅱ型为典型的致病型,Ⅰ、Ⅳ、Ⅴ型的致病专化性强,品种间抗感差异最大,Ⅰ、Ⅴ型的致病力相当,Ⅵ型的致病力与其他菌株差异最大;6类黑腐病致病型在陕西省大白菜主产区发生情况有明显差异,其中Ⅰ、Ⅴ致病型在陕西省4个大白菜主产区均有发生,Ⅰ致病型是陕西省大白菜黑腐病的主要菌原;病菌致病力与淀粉水解能力和明胶液化程度呈正相关。【结论】陕西省大白菜黑腐病病原菌的致病性分化明显,目前的主要病原菌是Ⅰ致病型。

【Objective】 The study clarified the pathogenesis division of black rot bacteria of Chinese cabbage（Brassica campestris L.ssp penkinsis） in Shaanxi Province,which will serve as a basis in breeding and indentification of Chinese cabbage and a gist in overall arrangement of various Chinese cabbages cultivars in Shaanxi Province to restrain black rot.【Method】 The representative leaves infected by black rot（Xanthomonas campestris pv.campestris（Pam.）Dowson） were first collected in central Chinese cabbage fields of shaanxi province,then the bacteria were separated,purified and classified with its morphologic characteristics and Koch＇postulates physiological target.Then 35 representative bacterium strains were obtained and used in cross inoculation and identification with seven different resistance Chinese cabbages.【Result】 Based on the response consistency with different hosts,the 35 strains were divided into 6 pathogenic types,with different infection characteristics,for instance,Type Ⅲ had the strongest infection capacity and type Ⅱ was the typical pathogenic strain.There were special infection capacity and wide response diversity among different hosts with Ⅰ,Ⅳ and Ⅴ strains,and there was similar infection capacity between Ⅰ and Ⅴ.However,type Ⅵ was obviously distinguished from other bacteria strains in infection capacity.It was also found that the infection capacity of them was positively related to hydrolysis capacity of amylum and degree of qlutin fluidifying.The ocuurences of the 6 kinds of pathogenesis were obviously different in Chinese cabbage in central productive area in Shaanxi Province.The strain Ⅰ and Ⅴ occurred in four main Chinese cabbage production fields in Shaanxi province,and strain Ⅰ was the predominant bacteria there.【Conclusion】 Therefore,it indicates that the black rot bacteria of Chinese cabbage have wide pathogenesis division and the predominant bacteria is strain Ⅰ in Shaanxi Province.