Autophagic chemicals effect for male-killing Wolbachia, Atg8 and TOR genes in Ostrinia scapulalis (Lepidoptera:Crambidae)

The adzuki bean borer Ostrinia scapulalis (Walker) is infected with male-killing Wolbachia, which selectively kills male offspring during the embryonic and larval development stages and allows the female offspring survive to adulthood. A high Wolbachia density leads to a strong male-killing effect. We utilized rapamycin and 3-methyladenine as an autophagy inducer and inhibitor to manipulate the autophagy which can change Wolbachia density and observed their effects on Wolbachia density in larvae and adults of O. scapulalis. Atg8 and TOR genes were exploited to predict autophagy activity. The relative density and expression of Wolbachia, Atg8, and TOR were counted by quantitative real-time PCR. We report that the relative density and expression of Wolbachia and TOR were reduced by rapamycin treatments, whereas the relative expression of Atg8 was increased in both the larval and adult treatments. The 3-methyladenine treatments exhibited an opposite effect to rapamycin, precisely, relative density and expression of Wolbachia and TOR were increased and relative expression of Atg8 was decreased. The female ratio of adults in the larval treatment and offspring in the adult treatments were not affected by the autophagic chemicals. The larval periods were significantly longer and the body weight decreased when the rapamycin was treated to the larvae. The mortality was increased by autophagic chemicals treatment. The abnormality of wing was observed more than normal wing by Rap treatments.