Oral Presentation International Plant Molecular Biology Conference 2024

Understanding Lr67: A hexose transporter variant associated with ion fluxes and multipathogen resistance (#337)

Ricky Milne 1 , Katherine Dibley 1 , Jayakumar Bose 2 , Peter R Ryan 3 , Stephen Tyerman 4 , Evans Lagudah 1
  1. CSIRO Agriculture and Food, Canberra, ACT, Australia
  2. School of Science, Western Sydney University, Richmond, NSW, Australia
  3. Research School of Biology, Australian National University, Canberra, ACT, Australia
  4. Australian Research Council Centre of Excellence in Plant Energy Biology, University of Adelaide, Adelaide, SA, Australia

Fungal diseases threaten crop quality and yield worldwide. An environmentally sound disease control method employs the plant immune system, however pathogens evolve to overcome plant-encoded resistance genes. Two main classes of genes exist in wheat (Triticum aestivum) that confer resistance to rusts and other fungal pathogens – seedling resistance (R) genes and adult plant resistance (APR) genes. Seedling R genes usually encode immune receptors and can confer strong resistance to single pathogen races at all developmental stages but may be rapidly overcome by pathogens, whereas APR genes can confer durable yet partial resistance to multiple pathogen species. We investigated a particular wheat APR gene able to confer partial resistance to multiple fungal pathogens – Lr67res. This gene encodes a sugar transport protein 13 (STP13) variant that differs from the wild type allele by two amino acids. Of those mutations, we find that the G144R mutation alone underpins disease resistance. Interestingly, this mutation can be transferred into other plants for resistance to fungal pathogens that do not colonise wheat. Enhanced anion fluxes were associated with Lr67res in Xenopus laevis oocytes and we aimed to determine whether ion associated phenotypes were also present in other biological systems. Lr67res yeast cells were sensitive to growth on media supplemented with NaCl and a leaf tip necrosis phenotype was induced by NaCl treatment in wheat carrying Lr67res. Together these results not only suggest altered anion fluxes may contribute to disease resistance, but also indicate that an abiotic component could be a factor in Lr67res-mediated resistance.