感染稻水象甲的Wolbachia基因组中插入序列的鉴定与分析

共生细菌Wolbachia对宿主的生殖起多种调控作用。以往研究表明, Wolbachia基因组中广泛存在插入序列(insertion sequence, IS), 它们对宿主基因组的可塑性、 多样性和进化起重要作用。稻水象甲Lissorhoptrus oryzophilus Kuschel在东亚是一种外来水稻害虫, 在原产地北美营两性生殖, 而在所有入侵地均营孤雌生殖。本研究采用PCR法从河北唐海孤雌生殖型稻水象甲体内克隆获得了Wolbachia的2条IS序列, 即ISWosp4和ISWosp6; 从美国德克萨斯州两性生殖型稻水象甲成虫体内克隆获得了Wolbachia的2条IS序列, 即ISWosp3和ISWosp5。碱基序列比对显示: ISWosp3和ISWosp4属于IS3家族IS3组成员, ISWosp5为IS4家族IS231组成员, ISWosp6为IS5家族IS1031组成员。对这些IS的ORF结构、 所编码氨基酸序列的结构等进行了分析, 推测ISWosp5具有潜在转座活性。所得结果增进了我们对Wolbachia IS3, IS4和IS5家族插入序列的认识, 同时为今后从IS的角度探讨Wolbachia与稻水象甲生殖的关系奠定了基础。

Identification and analysis of insertion sequences in the genome of Wolbachia infecting the rice water weevil,Lissorhoptrus oryzophilus(Coleoptera:Curculionidae)

The endosymbionts Wolbachia can cause various reproductive alterations to their hosts. Previous reports indicate that the mobile genetic elements, insertion sequences (ISs), are widely distributed in Wolbachia genomes and can extensively modify the plasticity, diversity and evolution of the bacterial genome. The rice water weevil, Lissorhoptrus oryzophilus Kuschel, is an alien insect pest of rice in Eastern Asia, which reproduces bisexually in its native regions but reproduces parthenogenetically in all of invaded areas. In this study, by using PCR we cloned two ISs, ISWosp4 and ISWosp6, from the Wolbachia infecting parthenogenetic rice water weevils collected from Tanghai, Hebei, China, and two ISs, ISWosp3 and ISWosp5, from the Wolbachia infecting sexual weevils collected from Texas, USA. Nucleotide sequence alignment suggested that ISWosp3 and ISWosp4 can be grouped to IS3 group in IS3 family, ISWosp5 to IS231 group in IS4 family, and ISWosp6 to IS1031 group in IS5 family. The ORF structure and deduced amino acid sequences of these ISs were analyzed, and ISWosp5 was speculated to have potential transposition activity. The findings can enrich our knowledge on the insertion sequences of IS3, IS4 and IS5 families, and can serve as a basis for future studies concerning interactions of Wolbachia and the rice water weevil.