Application and development prospect of RNA interference technology in pest control

Abstract

Chemical pesticides have been gradually replaced by other methods for controlling pests and pathogens in the agriculture, due to the serious “3R” problems (resistance, resurgence, and residue) caused by them. Meanwhile transgenic crops expressing Bacillus thuringiensis (Bt) toxins have been extensively planted for insect pest control, but the evolution of Bt resistance in target pests threatens the sustainability of the approach. The researches to find new ways for controlling pests effectively never stop. Biological control for pest has gained acceptance in recent years with the advantages of no pollution and continuous effects. However, the biological methods are also facing many problems: their effectiveness are strongly affected by environmental factors or the insect host; it is difficult to get large numbers of natural enemies’ insects by artificial reproduction and it is very expensive for producing insect natural enemies in laboratories. With the development of molecular biology technology, it has become a new trend for biological pest control by using modern molecular biological targets. RNA interference (RNAi) is a highly conserved post-transcriptional gene silencing mechanism that existed in insects by which the mRNA is targeted for degradation by the double-stranded RNA (dsRNA) or the inducing homologous mRNA, resulting in the sequence specific inhibition of gene expression. RNAi technology not only plays an important role in the study of insect functional genome, but also has great potential in pest control. RNAi was listed as one of the top ten scientific breakthroughs by Science magazine in 2001, and it was also awarded of the Nobel Prize for its discoverers in 2006. RNAi has high efficiency and strong specificity, and it is widely used for studying the function of the target gene or explore experimental treatment for diseases. When the target genes in insects was knocked down via RNAi, it always led to insect death or behavioral defects. This method is an environmentally friendly biotechnological one for pest control, and it rarely causes resistance with other insecticides. Therefore, RNAi technology is considered as a potential pest control strategy, which has great potential, beneficial in insect protection, development of new pesticide, etc., and this has been successfully used in Hemiptera, Orthoptera, Diptera insects and others. In this paper the silencing mechanism of RNAi, several ways of dsRNA transplanting into insects, and factors determining RNAi efficiency on application of insect are mainly described. Finally, we also reviewed the existing problems and some current solutions of RNAi technology, in order to discuss further the mechanism and existing problems of RNAi that applied in pest control. This will provide a new insight in pest management by RNAi technology.