Abstract - Fungal pathogens are a major constraint to global crop production, hence plant genes encoding pathogen resistance are important tools for combating disease. Many of the known pathogen-resistance genes contain nucleotide binding-leucine rich repeat (NLR) domains, are pathogen- or race-specific, and are prone to being overcome by pathogens. A small number of resistance genes provide a partial yet durable resistance to multiple pathogens. One example is the Lr67 gene in wheat, which confers partial resistance to multiple biotrophic pathogens including stem rust, stripe rust, leaf rust and powdery mildew. Lr67 is a plasma membrane protein of the STP13 hexose transporter subfamily and two variants exist – susceptible and resistant, which differ by two amino acids located in transmembrane regions (G144R, V387L). The susceptible variant, Lr67sus, functions as a high affinity hexose/proton symporter whereas the resistant variant, Lr67res, is incapable of transporting hexoses. Our findings indicate that Lr67res has a novel gain-of-function over Lr67sus that is linked with the resistance phenotype and may cause physiological changes in planta that hinder pathogen development. Moreover, only a single mutation (G144R) is required to confer the resistance phenotype, signifying the possibility of engineering this rare, broad-spectrum disease resistance trait to other crops in the future.
Biography - Ricky is a Postdoctoral researcher from Evans Lagudah’s team in the Crop Immunity Group at CSIRO Agriculture and Food, Canberra. His research focuses on understanding the mechanism of the wheat Lr67 hexose transporter variant that confers broad-spectrum resistance to fungal pathogens, and exploring the transferability of this resistance to other economically important crops.