一种导致浙江地区蝴蝶兰软腐病发生的病原菌分离鉴定及品种抗性评价

为明确浙江地区蝴蝶兰软腐病的病原种类以及不同蝴蝶兰品种对软腐病的抗病性差异，采用形态学、生理生化特性研究和系统发育学对蝴蝶兰软腐病进行病菌分离鉴定，应用离体叶片接种法评估不同蝴蝶兰品种抗病性。结果表明：1）蝴蝶兰软腐病病原菌为革兰氏阴性菌，在营养琼脂培养基（不含葡萄糖）上菌落呈乳白色圆形或近圆形，在营养琼脂甘油锰培养基上菌落呈浅紫色，菌体呈杆状。2）基于16S rRNA、dnaX、gapA和recA基因构建多基因联合系统发育树，结果表明菌株B与Dickeya fangzhongdai B16为同一分支。3）对40个蝴蝶兰品种进行离体叶片抗软腐病评价，鉴定出1个高抗品种（‘ES L20’）、1个抗病品种、14个中抗品种、18个感病品种和6个高感品种。本研究鉴定出一种导致浙江地区蝴蝶兰软腐病的病原菌，提供了部分蝴蝶兰品种的抗软腐病信息，为深入研究该病害发生规律及防治，培育抗病品种提供理论依据。

Isolation and identification of a pathogenic bacterium causing soft rot of Phalaenopsis in Zhejiang Province and variety resistance evaluation

In order to clarify the pathogen species of soft rot of Phalaenopsis in Zhejiang Province and the difference in disease resistance of different Phalaenopsis varieties， the pathogen of Phalaenopsis soft rot was isolated and identified by the morphology， physiological and biochemical characteristics of bacteria and phylogenetic analysis. The resistance of different Phalaenopsis varieties to soft rot was evaluated by in vitro leaf inoculation method. The results showed that： 1） The pathogenic of Phalaenopsis soft rot were Gram-negative bacteria. The colonies were milky white round or nearly round on nutrient agar （NA） medium （without glucose）， and the colonies were light purple on nutrient glycerol manganese （NGM） medium. The single bacterium was observed to be rod-shaped. 2） Based on 16S rRNA， dnaX， gapA and recA genes， a multi-gene phylogenetic tree was constructed， and the analysis showed that strain B belongs to the same branch as Dickeya fangzhongdai B16. 3） The resistance of 40 Phalaenopsis varieties to soft rot in vitro was evaluated. It was discovered that there are 1 high resistant variety ‘ES L20’， 1 resistant variety， 14 moderately resistant varieties， 18 susceptible varieties and 6 highly susceptible varieties were identified. In this study， the pathogen causing soft rot of Phalaenopsis in Zhejiang Province was identified， and the resistance information of some Phalaenopsis varieties was provided. This study laid a foundation for further research on the characteristics of disease occurrence and prevention methods and breeding disease-resistant varieties.