Abstract

Monochamus alternatusHope (Coleoptera: Cerambycidae), an invasive beetle that has caused billions of dollars of economic losses, is a serious pest ofPinus massonianain many Asian countries. An efficient RNAi system is helpful for functional genomics research onM. alternatus. In this study, a tryptophan 2,3-dioxygenase (TDO) related to the ommochrome synthesis in insects was identified. Using RNAi technology, theM. alternatus TDOgene was silenced by injecting dsRNA into pupae, and individuals were analyzed by phenotype and expression of theTDOgene by RT-qPCR. The results show thatTDOis expressed in different developmental stages ofM. alternatus, having its peak expression during the prepupal stage. White-eye phenotypes were observed in the pupal and adult stages after dsRNA injection, and a significant 81% decrease inTDOmRNA levels 48 h after injection was determined by RT-qPCR. This gene can be used as a genetic marker and is an important discovery for future genetic engineering tools to controlM. alternatuspopulations.Keywords:pine wilt disease;dsRNA;TDOgene;white gene;eye pigmentation