Directed evolution of immune receptors for broad-spectrum effector recognition

We engineered immune receptors that bind previously unrecognized pathogen effectors through directed evolution. From a library of variants generated through random mutagenesis of the ligand binding domain of a rice NLR immune receptor, we identified variants that bind multiple effectors from the fungal pathogen Magnaporthe oryzae. The engineered receptor recognized effectors that escape detection by natural NLR alleles and expanded recognition to a sequence divergent effector in the MAX family. Together, directed evolution and in planta testing can help develop crops with broad spectrum pathogen resistance and advance our mechanistic understanding of ligand recognition for immune signaling.