Wolbachia在山楂双叶螨中的感染及对寄主生殖的影响

Infection and reproductive effects of Wolbachia in the hawthorn spider mite,Amphitetranychus viennensis(Acarina: Tetranychidae)

【目的】共生菌Wolbachia在多种叶螨寄主中引起细胞质不亲和及适合度改变,影响寄主的生物学特性。山楂双叶螨Amphitetranychus viennensis是重要的果树害螨,常暴发成灾。本研究旨在明确Wolbachia在山楂双叶螨中的感染情况及对寄主生殖的影响。【方法】采集自然种群的山楂双叶螨,运用多位点序列分型技术(multilocus sequence typing,MLST)对其体内Wolbachia感染率及株系进行分析;通过杂交试验及生物学观察,分析感染Wolbachia对山楂双叶螨单雌产卵量、后代孵化率、性比及死亡率的影响。【结果】山楂双叶螨自然种群感染一种株系的Wolbachia(wVie),该Wolbachia株系与小黑花椿象Orius strigicollis和丽蝇蛹集金小蜂Nasonia vitripennis中的Wolbachia株系亲缘关系较近,而与叶螨属Tetranychus叶螨感染的Wolbachia株系亲缘关系较远。Wolbachia与4种分化较小的线粒体单倍型相关联。Wolbachia感染雌虫与不感染雌虫产卵量没有显著差异(P>0.05)。不感染雌虫与感染雄虫交配,卵孵化率显著低于其他杂交组合(P<0.05),但孵化率仍达近75%。各交配组合的后代性比及死亡率变化不明显(P>0.05)。【结论】Wolbachia在山楂双叶螨种群中的侵染历史较短,对山楂双叶螨的产卵力、后代性比、死亡率没有影响。Wolbachia在山楂双叶螨中诱导产生弱的CI表型。

【Aim】Endosymbiont Wolbachia can induce cytoplasmic incompatibility（CI） and alterative fitness in spider mites,affecting the biological characteristics of hosts. The hawthorn spider mite,Amphitetranychus viennensis,is one of the most important pest mites on fruit trees and often causes serious damage to agricultural industry. This study aims to clarify the infection status and reproductive effects of Wolbachia in A. viennensis. 【Methods】The Wolbachia infection in natural population of A. viennensis was analyzed using multilocus sequence typing（ MLST）. By crossing and biological experiments,the effects of Wolbachia on the fecundity,offspring hatchability,sex ratio and mortality of the host A.viennensis were investigated. 【Results】A. viennensis was infected with a Wolbachia strain,wVie,which has a closer phylogenetic relationship with Wolbachia from Orius strigicollis and Nasonia vitripennis than with Wolbachia from spider mites of Tetranychus genus. Wolbachia are associated with four little divergent mitochondrial haplotypes. Fecundity of infected and uninfected females did not differ significantly（ P 〉0. 05）. When infected males mated with uninfected females,the egg hatching rate was significantly lower than that in other cross combinations（P 〈 0. 05）,but the hatchability still reached 75%. The offspring sex ratio and mortality of each cross did not change significantly（ P 〉 0. 05）. 【Conclusion】Wolbachia infection in A. viennensis is a recent event and has no effect on host fecundity,offspring sex ratio and mortality. Wolbachia induces weak CI in A. viennensis.