Transgenic cotton expressing CYP392A4 double-stranded RNA decreases the reproductive ability of Tetranychus cinnabarinus.

As a polyphagous pest, Tetranychus cinnabarinus has the ability to overcome the defense of various hosts, and causes severe losses to various economically important crops. Since the interaction between pest and host plants is a valuable clue to investigate potential ways for pest management, we intend to identify the key genes of T. cinnabarinus for its adaption on cotton, then, with RNA interference (RNAi) and transgenic technology, construct a transgenic cotton strain to interfere with this process, and evaluate the effect of this method on the management of the mites. The difference of gene expression of T. cinnabarinus was analyzed when it was transferred to a new host (from cowpea to cotton) through high-throughput sequencing, and a number of differentially expressed genes involved in detoxification, digestion and specific processes during the development were classified. From them, a P450 gene CYP392A4 with high abundance and prominent over-expression on the cotton was selected as a candidate. With transgenic technology, cotton plants expressing double-stranded RNA of CYP392A4 were constructed. Feeding experiments showed that it can decrease the expression of the target gene, result in the reduction of reproductive ability of the mites, and the population of T. cinnabarinus showed an apparent fitness cost on the transgenic cotton. These results provide a new approach to restrict the development of mite population on the host. It is also a useful attempt to control piercing sucking pests through RNAi and transgenic technology.