两个EoNPV毒株对茶尺蠖和灰茶尺蠖的毒力差异

通过确定不同茶尺蠖核型多角体病毒（Ectropis obliqua nucleopolyhedrovirus,EoNPV）毒株对茶尺蠖（Ectropis obliqua）和灰茶尺蠖（Ectropis grisescens）毒力水平的差异,为有效提高茶尺蠖病毒的防效提供理论基础。采用浸渍法,测定EoNPV浙江毒株（EoNPV-ZJ）和江西毒株（EoNPV-JX）对茶尺蠖和灰茶尺蠖3龄幼虫的毒力水平;通过克隆测序,多重比较分析EoNPV-ZJ和EoNPV-JX毒株同源重复区（hrs）。结果表明,EoNPV-JX对灰茶尺蠖和茶尺蠖3龄幼虫14 d的LC₅₀分别为5.95×10⁶ PIB·mL^-1和3.14×10⁶ PIB·mL^-1,EoNPV-ZJ对灰茶尺蠖和茶尺蠖3龄幼虫14 d的LC₅₀分别为1.13×10⁷ PIB·mL^-1和5.04×10⁶ PIB·mL^-1。EoNPV-JX和EoNPV-ZJ的hr1大小均为1 795 bp,含有11个完全回文序列,hr3大小均为665 bp,含有3个完全回文序列,与已报道的安徽毒株（EoNPV-AH）无差异;而hr2差异较大,其中EoNPV-JX hr2为864 bp,含有7个完全回文序列,EoNPV-ZJ hr2为1 168 bp,含有12个完全回文序列,均少于EoNPV-AH的18个完全回文序列。综合分析显示,EoNPV不同毒株对茶尺蠖的毒力水平高于其近缘种灰茶尺蠖;EoNPV-JX毒株对灰茶尺蠖的毒力高于EoNPV-ZJ毒株,造成EoNPV不同毒株毒力差异的主要原因可能与其hr2序列回文序列个数相关。

Virulence Difference of Two Strains of EoNPV Isolates to Ectropis obliqua and Ectropis grisescens

The virulence differences of Ectropis obliqua nucleopolyhedrovirus (EoNPV) from different isolates to Ectropis obliqua and Ectropis grisescens were analyzed, which provided a basis for effectively improving the control effect of EoNPV. The virulence of EoNPV Zhejiang strain (EoNPV-ZJ) and EoNPV Jiangxi strain (EoNPV-JX) to third instar larvae of E. obliqua and E. grisescens were determined by leaf dipping. The homologous regions (hrs) of EoNPV-ZJ and EoNPV-JX were further sequenced and analyzed by multiple sequence alignment. The results indicate that the 14 d LC₅₀ of EoNPV-JX to E. grisescens and E. obliqua were 5.95×10⁶ PIB·mL^-1 and 3.14×10⁶ PIB·mL^-1, respectively, while the 14 d LC₅₀ of EoNPV-ZJ to the two tea geometrid moths were 1.13×10⁷ PIB·mL^-1 and 5.04×10⁶ PIB·mL^-1, respectively. The hr1 of EoNPV-JX and EoNPV-ZJ were both 1 795 bp in size, containing 11 complete palindrome sequences, and hr3 were both 665 bp in size, containing 3 complete palindrome sequences, which were the same as EoNPV Anhui strain (EoNPV-AH). However, the hr2 regions of the three strains were different. The hr2 of EoNPV-JX was 864 bp in size and contained 7 complete palindrome sequences, and it was 1 168 bp in size and contained 12 complete palindrome sequences in EoNPV-ZJ, all of which were less than the 18 complete palindrome sequences of hr2 in EoNPV-AH. Our study suggests that the virulence of different strains of EoNPV to E. obliqua were higher than that of its related species, E. grisescens, while the toxicity of EoNPV-JX to E. grisescens was more than that of EoNPV-ZJ. The sensitivity of E. obliqua to EoNPV was higher than that of E. grisescens. The virulence of EoNPV might be related to the number of palindromes of hr2.