Title: Interfering the expression of insect genes potentially involved in vector transmission of plant viruses using RNAi-based strategies

Presenter: Dr.Juan Jose Lopez-Moya 

University: Centre for Research in Agricultural Genomics, CRAG, CSIC-IRTA-UAB-UB Campus UAB, Bellaterra, Spain

Time: 9:00-10:00, July 19, 2013

Venue: Room A203, Institute of Microbiology, Chinese Academy of Sciences

Abstract: Transmission by vector organisms is the most usual method of dissemination of plant viruses. Homopteran insects like aphids and whiteflies are vectors of numerous viruses, and therefore their control is often considered among the strategies to fight against viral diseases. However, the effectivity of insecticide treatments is far from adequate to avoid dissemination of many viruses, in particular non-circulative transmitted ones which are acquired and inoculated by insect vectors in short periods of time. Interfering the virus transmission process will be an alternative for virus control. Interference with transmission could be designed considering the specific molecular interactions among the virus and the insect during the process. Using aphid-transmitted potyviruses as experimental model, we are exploring the use of RNAi-based strategies to target specific vector genes that might be essential for transmission. Potyviruses are transmitted in a non-persistent manner with a viral auxiliary factor, the HCPro protein, mediating the reversible retention of virions to the stylet of the vector. Using purified HCPro as bait, aphid proteins specifically interacting with the potyviral HCPro have been identifyed, and the involvement in virus dissemination of these candidates could be validated functionally using RNAi to knock down their expression in aphids. Two procedures for RNAi are being evaluated: the first one is based on feeding insects in artificial diets supplemented with dsRNAs generated in vitro, and the second one takes advantage of unrelated plant virus-based expression vectors containing fragments of the targetted genes to induce accumulation in planta of specific siRNAs. Aphids fed on the artificial diets with dsRNAs, or on plant tissues producing siRNAs were subsequently analyzed by quantitative RT-PCR to measure accumulation of the targeted gene transcripts. In addition to provide new tools for understanding the mechanisms of virus transmission, the final goal of this research efforts will be to design novel strategies for virus control based on targeting specifically the expression in the insect vector of elements essential for transmission.