昆虫病原线虫共生菌BP品系杀虫毒素基因xptA2的杀虫活性分析  

Insecticidal activity of insecticidal toxin gene xptA2 in Xenorhabdus nematophila BP

作　　者：崔龙[1] 王勤英[1] 邱礼鸿[2] 庞义[2] 

机构地区：[1]河北农业大学植物保护学院,保定071001 [2]中山大学生物防治国家重点实验室/昆虫研究所,广州510275

出　　处：《植物保护学报》2005年第4期407-410,共4页Journal of Plant Protection

基　　金：国家自然科学基金(30400296)

摘　　要：为进一步研究嗜线虫致病杆菌 Xenorhabdus nematophila 杀虫毒素基因簇中各基因的功能,从BP 品系的粘粒文库中筛选出一个粘粒克隆 XnBP83包含全部的 xpt 基因,对该粘粒克隆进一步亚克隆得到一个亚克隆菌株 Sub9.0,只有一个 xpt 基因 xptA2。以 Sub9.0为研究对象,对 xptA2的功能作了进一步研究。结果表明,xptA2基因的表达产物与其它 xpt 基因的表达产物物理混合后无明显增效作用,而将 xptA2转入缺失 xptA2的粘粒克隆 XnBP76和 XnBP203后,也同样无明显增效作用。对 xptA2的序列分析发现,BP 品系的 xptA2预测氨基酸序列与已发表序列相比明显存在2个变异区。进一步 BLAST 分析发现,这2个变异区同昆虫病原线虫共生菌中与口服毒性有关的杀虫毒素蛋白具有同源性。The insecticidal toxin genes in Xenorhabdus nematophila BP can express toxin proteins that have high insecticidal activity to many Lepidoptera larvae. As a kind of candidate toxin gene for transgenic insect-resistant plants, it is very important to found out the relationships of these genes. Subg. 0, one subclone of a cosmid clone XnBP83 from Xenorhabdus nematophila BP which has all xpt insecticidal genes, was used for studying the function of xptA2 in X. nematophila because only xptA2 presented in this subclone. It was found that protein expressed by xptA2 had oral toxicity to Heliothis armigera but the full oral toxicity of XnBP83 could not be restored when physical mixing of toxins expressed by the 3 genes, xptB1, xptC1 and xptA2. The full oral toxicity of XnBP83 could not be restored when xptA2 was transformed into XnBP76 or XnBP203. Two varied regions were found in the deduced amino acid of xptA2 of X. nematophila BP comparing with that in PMFI296. BLAST results showed that the two regions had homology with XptA1 in X. nematophila PMF1296 and TcdA in P. luminescens W14 which were thought to be associated with oral toxicity to insects.

关 键 词：嗜线虫致病杆菌BP品系 杀虫毒素基因 功能分析 

分 类 号：S476.15[农业科学—农业昆虫与害虫防治] Q512.1[农业科学—植物保护]