Plant-mediated whitefly-begomovirus interactions

 

Patterns of plant-mediated whitefly-begomovirus interactions

The effects of a begomovirus on a whitefly vector, or vice versa, via their shared host plants can be mutualistic, neutral or negative, being context-dependent (Jiu et al. 2007; Liu et al. 2009, 2010; Li et al. 2011).

Mechanisms of plant-mediated positive effects between viruses and vectors

With regard to the mechanisms of plant-mediated positive effects, our study has shown that when tobacco plants were infected with tomato yellow leaf curl China virus (TYLCCNV), the jasmonic acid defenses and terpenoid synthesis in the plants were repressed but significant changes of nutrition were not detected, indicating that plant defenses play a key role in mediating the interactions in this system (Zhang et al. 2012; Luan et al. 2013). Moreover, infection of tobacco with TYLCCNV enhanced nutritional assimilation and vitellogenesis of whiteflies (Guo et al. 2012; Wang et al. 2012). More effort is being made to discover molecular mechanisms underlying this tripartite interaction.

Insect feeding affects plant susceptibility to viruses

Studies in our laboratory have shown that the order of infection of a host plant by a virus and its vector may induce different responses of the plants and in turn exert different effects on the virus and the vector insect. In some cases, vector and even non-vector insect feeding may reduce subsequent plant susceptibility to virus transmission (Li et al. 2017). One of the factors involved in inducing these changes is that whitefly pre-infestation activates the salicylic acid signaling pathway of plants, leading to deposition of callose that inhibited begomovirus replication/movement in the host plant.

 

 

Figure: Performance of the invasive MEAM1 (B) whitefly and the indigenous Asia II 3 (ZHJ1) whitefly on uninfected tobacco plants and plants infected by tobacco curly shoot virus (TbCSV) or tomato yellow leaf curl China virus (TYLCCNV) (Jiu et al. 2007).

Figure: Co-infection of betasatellite TYLCCNB with TYLCCNV (a) or the bC1 protein encoded by betasatellite (b) suppresses relative expression of jasmonic acid related genes in tobacco plants (Zhang et al. 2012).

 

 

Figure: Digital gene expression (DGE) and qRT-PCR revealed that the relative expression of the tobacco terpenoid synthesis gene 5-epi-aristolochene synthase was at higher levels in whitefly-infested plants, declined in virus-infected plants, and decreased slightly in co-infested plants (Luan et al. 2013).