中国欧李根癌病病原菌鉴定

Identification of pathogen of Chinese dwarf cherry crown gall disease in China

0引言欧李(Cerasus humilis(Bge.)Sok.)又称钙果、山梅子、小李仁等,是我国特有的野生型灌木类果树[1],具有独特的环境适应性和丰富的营养价值。自20世纪80年代以来,该果树作为我国西部地区的生态扶贫战略中重点栽培品种,种植面积不断扩大[2]。近年来,欧李根癌病发生严重,严重威胁产业发展[3]。根癌病主要发生在植物根及根颈部,在枝干上也时有发生。

Chinese dwarf cherry(Cerasus humilis(Bge.)Sok.)is a wild-type shrub fruit tree in China.In recent years,crown gall disease has become a major threat for the production of Chinese dwarf cherry.Here,we collected the root nodules of Chinese dwarf cherry from Shandong,Liaoning,Ningxia,Hebei and Inner Mongolia Provinces to identify the pathogen of Chinese dwarf cherry crown gall in these areas.We obtained a total of 24 isolates and performed morphological observation,sequence analysis and specific PCR detection,physiological and biochemical determination and pathogenicity determination.The colonies of these 24 isolates on the NA plate were white,round,middle convex,and had neat edges.It is most closely related to Agrobacterium tumefaciens in the 16S rRNA phylogenetic tree.Bioassays on sunflower and Chinese dwarf cherry seedlings indicated that all these isolates infected sunflower and Chinese dwarf cherry seedlings and stimulated gall formation at the inoculation site.The biotype was identified by specific physiological and biochemical measurements,which indicated that 21 out of the 24 pathogenic strains were biotypeⅠand 3 were biotypeⅡ.