一株高毒力致病杆菌CB6的鉴定

Identification of A Strain Xenorhabdus sp. with High Antibiotic and Insecticidal Activity

从北京郊区果园采集的小卷蛾斯氏线虫 (Steinernemacarpocapsae)肠道内分离到一株具有较强杀虫和抑菌活性的致病杆菌菌株CB6。形态特征及生理生化特征测定结果表明 ,CB6菌株与致病杆菌属 (Xenorhabdus)中的嗜线虫致病杆菌 (X .nematophila)种的特征基本一致。测定了该菌株的 16SrRNA序列并根据 16SrRNA序列构建了系统发育树 ;在系统发育树中 ,CB6菌株与嗜线虫致病杆菌其他 4个菌株形成一个类群 ,序列同源性大于 99%。但CB6菌株的酪氨酸酶、脂酶 (蛋黄 )的产生、核糖产酸等生化特征与嗜线虫致病杆菌种内的其他菌株存在一定的差异 ,且具有更强的杀虫和抑菌活性。因此认为CB6菌株是嗜线虫致病杆菌的一个变种 ,命名为嗜线虫致病杆菌北京变种(X .nematophilavar.pekingensis)。

Strain of Xenorhabdus sp. CB6 with high antibiotic and insecticidal activity was isolated from the intestine of Steinernema carpocapsae collected from orchard of Beijing, China. The morphology, physiological and biochemical characteristics were studied. The results indicated that its characteristics were most consistent with X. nematophila. The sequence of 16S rRNA fragements were analyzed. The homology between strain CB6 and other strains of X. nematophila is above 99%. Strain CB6 was clustered together with other four strains of X. nematophila in phylogenetic tree. But there are some differences in biochemical characteristics (e.g. tyrosinase, lipase, acid from ribose) with other strains of X. nematophlia, especially CB6 has high insecticidal and antibiotic activity. We suggested that strain CB6 was a variation of X. nematophila and named X. nematophila var. pekinegnsis.