The Symbiotic Bacterium Wolbachia Induced Cytoplasmic Incompatibility Of Aspersus And Impacted The Female Fecundity

Wolbachia is the most widely distributed intracellular symbiotic bacteria in nature,which can induced cytoplasmic incompatibility of the host,that is,when the male host infected with Wolbachia crosses with the uninfected female host,the progeny usually does not survive or the survival rate decreases.Velarifictorus aspersus is widely distributed in our country and is a common agricultural and forestry pest.Previous studies have shown that Wolbachia infection of V.aspersus,but it is not clear whether Wolbachia affects its reproduction.In this study,the infection of Wolbachia in Haikou population of V.aspersus was detected by PCR,quantitative fluorescence PCR and other molecular biological methods.The effect of Wolbachia on the reproduction of V.aspersus was discussed through the mating experiment of infected and Wolbachia-free strains.The main findings are as follows:(1)Using Wolbachia’s wsp gene primer,PCR detection was performed on the Haikou population of V.aspersus,and it was confirmed that all individuals tested were positive,with an infection rate of 100%,and all were doubly infected.Phylogenetic analysis showed that Wolbachia strains belonged to supergroup A and F,respectively,and were named wAsp-a and wAsp-f.(2)Quantitative fluorescence PCR was used to detect the abundance of Wolbachia in different tissues of V.aspersus at different developmental stages.It was found that the abundance of wAsp-a strain increased with the development of V.aspersus nymph,while wAsp-f strain had no significant change.The abundance of wAsp-f strain was higher than wAsp-a strain in both nymph stage and adult stage.(3)After tetracycline treatment,Wolbachia of V.aspersus could be successfully removed.The results of the mating experiments of Wolbachia-infected and Wolbachia-free strains showed that Wolbachia had only a slight effect on the developmental duration of their progeny,but had no significant effect on the female ratio of their progeny.However,the egg production of Wolbachia infected females was significantly higher than that of Wolbachia-infected females.The hatching rate of the offspring of Wolbachia-infected male adult and Wolbachia-free female was only 49%,significantly lower than that of other mating pairs.In conclusion,Wolbachia dual infection exists in the Haikou population of Vaspersu,belonging to supergroup A and supergroup F respectively.Wolbachia can induce incomplete cytoplasmic incompatibility of Vaspersu and improve reproductive ability of female adult Vaspersu.Because cytoplasmatic incompatibility is related to cifA and cifB genes of Wolbachia,while the strain of F supergroup does not have cifA and cifB genes,it can be believed that cytoplasmatic incompatibility of V.aspersus is induced by wAsp-a strain.