Thrips 'spit' at the interface of vector-virus-plant interactions

Interactions between insect vectors, plant viruses and their plant hosts is orchestrated by several intricate molecular interactions. The effect of vector-virus interactions on vector-plant host relationship is least understood. Frankliniella occidentalis, the western flower thrips (WFT), and orthotospoviruses interactions serve as a model for thysanopteran vectors to understand the outcomes of these association on the vector-plant interactions. In our study, using F. occidentalis and Tomato spotted wilt virus (TSWV), an orthotospovirus, we investigated the effect of virus on the vector-plant host interactions. TSWV is transmitted by thrips in a circulative-propagative manner. Larval stages are efficient acquirers whereas adults are efficient transmitters. Salivary gland tissue and saliva of adults provide a conduit for virus to inoculate the host plant. Male and female thrips exhibit sexual dimorphic TSWV transmission rates. We performed nano LC-MS/MS proteomics of adult salivary glands and saliva to test the hypothesis that TSWV infection of adult thrips salivary glands modulates the abundance and/or composition of proteins secreted by the adult thrips during feeding, and these modifications affect the thrips-plant host interactions. A candidate protein identified in the secreted saliva showed significant interactions with chloroplast and peroxisomal proteins in Arabidopsis cDNA library screening. Currently the effect of this candidate protein on plant defenses are being studied in planta.