Hybridization barriers: CRP signalling during pollen tube invasion, growth and guidance.

We aim to understand the (dual) role and specificity of polymorphic small cysteine-rich proteins/peptides (CRPs) for reproductive success and pathogen defence in maize. Using a comparative transcriptomics approach, we have profiled and analysed the expression pattern of CRPs and their potential target proteins in various reproductive tissues including pollen tubes, stigmata (silks) and silks invaded by pollen tubes, by the necrotic fungus Fusarium or the biotrophic fungus Ustilago. Here, we will identify and characterize CRP and their targets, likely ion channels and/or receptor kinases, at the pollen tube and fungal hyphae surface, and we will perform structure-function analyses to understand the specificity of the interactions.