Whitefly-plant interactions

Host plant ranges of different species of whiteflies

The cryptic species of whiteflies in the Bemisia tabaci complex are known to have different host ranges, which are a fundamental factor affecting the ecology of these whiteflies. However, the host plant record in the literature is a mixture for all species in the B. tabaci complex. The actual host range of each species of whiteflies is mostly unknown. Our experimental studies indicate that the invasive MEAM1 (B) and MED (Q) whiteflies have a much wide range of host plants than whiteflies indigenous to China (Zang et al. 2006; Xu et al. 2011). MEAM1 and MED whiteflies differ in their ranges of host plants as well, e.g. MEAM1 performs better than MED on brassicas plants while MED performs better than MEAM on pepper and bean plants. These differences of host ranges between species of whiteflies have been shown to be a major factor affecting their spread and competitive interactions.

Molecular and physiological mechanisms of host plant use

When attacked by whiteflies, plants initiate multiple levels of defence responses including the regulation of defence signal-transduction pathways and production of secondary metabolites. To counter plant defenses, whiteflies may regulate plant defense or detoxify plant toxins. Comparative transcriptional analyses between whitefly species indicate that compared to those of the native species, the genes related to basic metabolism and detoxification were expressed at an elevated level in the invasive whiteflies (Wang et al. 2013). Increase of genetic resources of whiteflies and application of RNA interfering in phloem-feeding insects provide us with unprecedented opportunities to reveal the molecular basis of differential capacity for utilizing various plants by the invasive and indigenous whiteflies. In particular, effort has been made to find effectors in the saliva of whiteflies that mediate the interactions between whiteflies and plants.