Chemical Genomics of the Plant Immune System and Development of Novel Non-Biocidal Reduced Risk-Pesticides

A major strategy of disease control in agriculture and horticulture has been the use of pesticides. However, public concern over the dangers of pesticide use has spawned considerable interest in alternative methods for pest control. Conventional pesticides typically rely on their toxic activity leading to environmental problems. Therefore, EPA has established a program to conveniently register environmentally-friendly reduced-risk pesticides. By high-throughput screening we identified over 100 drug-like compounds that induce natural plant immune responses in the model plant Arabidopsis thaliana (Arabidopsis) and which are likely non-biocidal. Such synthetic elicitors will facilitate the design of reduced-risk pesticides triggering the plant’s inherent defense capabilities without being toxic to other components of the biosphere. In addition, we are using synthetic elicitors as molecular probes to dissect regulatory processes controlling plant immune responses. Microarray analyses of synthetic elicitor-triggered responses in Arabidopsis combined with reverse genetics allowed us to uncover several novel components of the plant immune system. Constitutive activation of plant immunity by mutations or defense-inducing chemicals generally tends to reduce plant growth. We surprisingly found that low doses of one synthetic elicitor enhance growth of roots and aerial parts of Arabidopsis and tomato. Taking advantage of these hormesis-like effects we are designing novel chemistry-based strategies to increase crop vigor and biomass, while boosting immunity.