Abstract
Simple SummaryThe sweet potato whitefly, Bemisia tabaci, is a polyphagous, global invasive insect pest. It can damage vegetables and crops directly by feeding and indirectly by transmitting plant viruses. Previously, we showed that virus infection of host plants can promote B. tabaci MED (Q biotype) reproduction. Here, using a whitefly-tomato chlorosis virus (ToCV)-tomato system, we investigated how ToCV modulates B. tabaci reproduction to facilitate its spread. ToCV infection significantly increased whitefly fecundity and the relative expression of vitellogenin gene (Vg). Both ovarian development and fecundity of whitefly were suppressed when Vg expression was silenced with or without ToCV infection. These combined results reveal that ToCV infection increases B. tabaci MED fecundity via elevated vitellogenin gene expression.Transmission of plant pathogenic viruses mostly relies on insect vectors. Plant virus could enhance its transmission by modulating the vector. Previously, we showed that feeding on virus infected plants can promote the reproduction of the sweet potato whitefly, Bemisia tabaci MED (Q biotype). In this study, using a whitefly-Tomato chlorosis virus (ToCV)-tomato system, we investigated how ToCV modulates B. tabaci MED reproduction to facilitate its spread. Here, we hypothesized that ToCV-infected tomato plants would increase B. tabaci MED fecundity via elevated vitellogenin (Vg) gene expression. As a result, fecundity and the relative expression of B. tabaci MED Vg was measured on ToCV-infected and uninfected tomato plants on days 4, 8, 12, 16, 20 and 24. The role of Vg on B. tabaci MED reproduction was examined in the presence and absence of ToCV using dietary RNAi. ToCV infection significantly increased B. tabaci MED fecundity on days 12, 16 and 20, and elevated Vg expression on days 8, 12 and 16. Both ovarian development and fecundity of B. tabaci MED were suppressed when Vg was silenced with or without ToCV infection. These combined results suggest that ToCV infection increases B. tabaci MED fecundity via elevated Vg expression.
Highlights
Plant viruses are a serious threat to sustainable agriculture [1,2,3]
We found the developmental period for B. tabaci was 15 to 20 days in tomato plants when incubated in the whitefly rearing room
Fecundity was significantly increased on Tomato chlorosis virus (ToCV)-infected tomato plants on 12 d (F (58) = 9.920, p < 0.001), 16 d (F (58) = 5.005, p =0.012) and 20 d (F (58) = 0.310, p = 0.002)
Summary
Plant viruses are a serious threat to sustainable agriculture [1,2,3]. The transmission of plant pathogenic viruses mostly relies on insect vectors to the shared host plants [4,5,6].The complex interaction between the plant pathogenic viruses, the insect vectors, and the host plants could either directly or indirectly influence the abundance and distribution of the insect vectors [7], thereby affecting the spread of such virus diseases. Viruses could directly influence the insect vectors’ reproductive potential, impacting the abundance of the insect vectors and affecting the transmission efficiency of the viruses or indirectly through the shared host plants modification. B. tabaci and its associated plant viruses have caused substantial crop losses ranging from 20 to 100% [14] with increasing control costs [15]. Among these plant viruses, tomato chlorosis virus (ToCV, genus Crinivirus, family Closteroviridae) is a globally distributed, rapidly-spread virus [16]. Deciphering the mechanism of ToCV mediating whitefly reproduction could help understand ToCV epidemiology and develop novel and effective control methods
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