Enhancing trap crops: testing RNAi potential in planta to target sap-feeding insects.

Greenhouse conditions allow the rapid growth of many pest populations, including aphids, whiteflies, and leafhoppers. These sap-feeding insects can cause considerable damage through direct harm to plant vitality and growth, as well as damage due to plant pathogens they vector. Furthermore, many of these sap-feeding pests have developed resistances to a variety of insecticides, making it difficult to control pest populations. As a result, alternative control strategies have been developed. One technology at the forefront of crop protection research is RNA interference (RNAi), which exploits intracellular gene regulation mechanisms in order to suppress gene expression of a particular target by introducing double-stranded RNA (dsRNA). Through transgenic plants producing dsRNA for essential insect genes, RNAi technology can be combined with visual or olfactory targeting trap crops in order to develop an enhanced trap crop that can attract and then kill these insects. However, plant transformation can be costly, and in-vitro studies can give misleading results due to the scale. Using aeroponically-grown Solanum lycopersicum (cv. Micro-Tom) for root uptake of dsRNA targeting an essential gene in the greenhouse whitefly (Trialeurodes vaporariorum), we were able to more accurately evaluate insect mortality over time compared to in-vitro studies. Development of this model may allow for more precise testing of RNAi application in planta (using trap crop candidates) and can act as a possible precursor to plant transformation.