Gene silencing applied to development of transgenic sugarcane plants resistant to the sugarcane weevil, Sphenophorus levis

Abstract

Larvae of the sugarcane weevil Sphenophorus levis are major pests of sugarcane plantations in the state of São Paulo, Brazil, and no control method has yet proven effective against this insect. Insect control strategies based on RNA interference have been used as an efficient tool for silencing genes. Thus, the aim of the present research project is to develop sugarcane strains employing gene silencing to generate resistance to weevils. For such, S. levis will be reared in the laboratory; feeding assays will be performed by applying double-stranded RNA (dsRNA) and sugarcane strains will be transformed with specific constructs for the production of dsRNA to activate gene-silencing mechanisms in insects fed on transgenes. Plants will be transformed with constructs containing fragments of V-ATPase E and serpin 1 genes from S. levis, using a constitutive promoter as well as a promoter inducible by herbivory. In addition to the validation of the dsRNA production system in sugarcane, new specific, lethal target genes will be selected for in vivo testing using these dsRNAs in feeding experiments. The transformed plants will be challenged in the laboratory to determine resistance against insect attack. Therefore, we expect to validate the dsRNA production system in sugarcane plants resistant to S. levis for producing pest-resistant varieties, which should significantly contribute to reduce losses due to insect attack.