From the cell surface to the field: Receptor-mediated herbivore induced defenses in legume crops

Abstract

The recognition of herbivore-associated molecular patterns (HAMPs) via pattern recognition receptors (PRRs) initiates signaling cascades that lead to the accumulation of direct and indirect defenses against herbivorous pests. Inceptin 11 (In11) is a peptide HAMP present in the oral secretions of Lepidoptera caterpillars that triggers these defense responses in legume crops. In11 is recognized by the Inceptin Receptor (INR), which induces changes in gene expression preceding the accumulation of antiherbivore defenses. However, the molecular mechanisms regulating In11-induced defenses via INR remain largely unexplored.This dissertation proposes a molecular mechanism by which In11-induced genes encoding gut-stable direct defenses are transcriptionally regulated by the plant circadian clock. Furthermore, this work demonstrates that INR is required in legumes for the In11-induced attraction of predators, which act as indirect defenses against herbivores in the field. These findings provide the first evidence of a time-dependent response to a specific HAMP and directly link core circadian clock transcription factors to plant immunity against herbivores. Lastly, this study presents the first conclusive molecular and ecological evidence that a specific plant immune receptor directly controls ecologically relevant tritrophic interactions.