Encounter With a Selfish Virus Sabotages Its Vector to Orient Toward Requisite Host Plant: A Case Study With Chili Leaf Curl Virus-Whitefly

Abstract

Interactions of a virus with its vector and host plant have challenged entomologists, pathologists and biologists alike. Phytophagous insects depend on specific host volatile cues to locate suitable host plants for feeding and oviposition. Several studies have revealed that plant viruses modify their insect vector’s orientation toward specific host plants to facilitate their spread and survival. The ecological and molecular basis of this vector behavior modification remains largely unknown and was therefore explored in this study. Interestingly, host volatile preference for non-viruliferous female whiteflies [Bemisia tabaci (Genn.)] was found to be preferentially oriented toward infected chili plant [with chili leaf curl (ChLCV)] volatiles, while viruliferous whiteflies preferred healthy chili plant (Capsicum annum L.) volatiles in olfactometer. The electrophysiological studies involving electroantennogram (EAG) assays exhibited similar trend in EAG response amplitudes. Gas Chromatography linked electroantennodetection (GC EAD) revealed specific plant volatile cues responsible for altered host orientation behavior of the vector. Transcriptome profiling of the viruliferous and non-viruliferous whiteflies and Realtime qPCR validation showed differential expression of certain odorant binding proteins (OBPs) in viruliferous whiteflies. Our results suggest that there is a plant virus mediated altered chemoecological behavior in the vector with respect to orientation toward its host plant. Based on the findings we speculate that the virus mediates such change in the vector for a continued transmission success to the host.