Plant-mediated indirect effects of two viruses with different transmission modes on Bemisia tabaci feeding behavior and fitness

Abstract

Viral infections can induce phenotypic modifications on plant cues that mediate host plant colonization by vectors. It has been postulated that virus transmission mode influences the way in which virus infection alters the vector´s probing behavior and fitness on plants in order to optimize transmission. We evaluated the indirect effects of tomato plant infection by a semipersistently transmitted crinivirus, Tomato chlorosis virus (ToCV), and a persistently transmitted begomovirus, Tomato severe rugose virus (ToSRV), on the biological parameters and probing behavior of Bemisia tabaci MEAM1, using the electrical penetration graph (EPG) technique. There was a deleterious effect on the viability of nymphs developed on ToCV- or ToSRV-infected tomato plants, but no effects on reproductive parameters of emerged adults, in comparison to mock-inoculated plants. The EPG analysis showed a delay in starting to probe and fewer probing attempts on ToCV-infected plants, suggesting that ToCV infection reduces plant palatability. No virus-indirect effect was observed on the insect´s probing behavior in the phloem tissue. Our combined results show that tomato infection by viruses with two different transmission modes affected the development of the whitefly vector similarly, with neutral effects on probing behavior parameters associated with virus acquisition in the phloem, and thus no apparent benefits for virus spread.