空心菜青枯病病原菌的鉴定

Pathogen identification of bacterial wilt of Ipomoea aquatica

空心菜青枯病是近年来在广东空心菜产区新发生的病害,病株率一般为5%~20%,严重达50%以上。症状初始表现为植株上部1~2片叶萎蔫、下垂,病叶失去光泽呈灰绿色;随着病情的发展,病叶不断增多,最终整株萎蔫,甚至倒伏。经细菌学鉴定、室内致病性测定、16S rDNA序列比较及系统进化分析,结果表明引起该病害的病原是茄科雷尔氏菌（Ralstonia solanacearum）;致病性和碳水化合物利用试验结果表明,该病原菌属茄科雷尔氏菌1号生理小种,生化变种4。

The bacterial wilt of Ipomoea aquatica is a new disease in Guangdong province in recent years. The incidences of diseased plants were 5% -20% in the fields, even more than 50%. Initially, one or two upper leaves of the diseased plants wilted and became gray-green. Along with the disease developing, the diseased leaves of the plants increased. And finally, the whole plants completely wilted, even collapsed. By using bacteriological identification, pathogenicity tests, 16S rDNA sequence comparison and phylogenetic relationships analysis, the bacterial wilt of L aquatica was caused by Ralstonia solanacearum. The results of pathogenicity and carbohydrate utilized test demonstrated that the tested strains of the pathogen belonged to race 1 and biovar 4 of R. solanacearum