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Poster

Session: Session 2 Presenting Authors at Posters (Evens)

P-200 - Engineering MLA-NLR immune receptors for novel effector recognition in cereal crops

Thursday, July 17, 2025
13:30 - 15:15  
Location: Confex Hall 3
Engineering plant-microbe traits

    Presenting Author(s)

  • XZ

    Xiaoxiao Zhang

    The Australian National University
    Canberra, Australian Capital Territory, Australia

    • Author(s)

  • BD

    Bayantes Dagvadorj

    The Australian National University
    Canberra, Australian Capital Territory, Australia

  • JG

    Jialing Gao

    The Australian National University
    Canberra, Australian Capital Territory, Australia

  • LM

    Lucy M. Molloy

    The Australian National University
    Canberra, Australian Capital Territory, Australia

  • LC

    Lauren M. Crean

    The Australian National University
    Canberra, Australian Capital Territory, Australia

  • SW

    Simon J. Williams, PhD (he/him/his)

    The Australian National University
    Canberra, Australian Capital Territory, Australia

  • JR

    John P. Rathjen

    The Australian National University
    Canberra, Australian Capital Territory, Australia

Natural plants rely on high diversities of resistance (R) genes to provide effective disease resistance to disparate pathogens; however, R gene diversity has been significantly reduced in modern crops, leading to short-lived resistance, as pathogens evolve rapidly to overcome R genes recognition. To increase R gene diversity in cereal crops, this study explored natural sequence variations present in wheat, barley and wild grass relatives, targeting the Mildew resistance locus A (Mla) R gene family. The Mla-R genes encode NLR immune receptor proteins that confer resistance against multiple unrelated plant pathogens through recognizing and binding to pathogen-specific proteins, termed effectors. Using DNA shuffling, we generated variant libraries recombining the barley and wheat Mla genes in vitro. The variant library recombining barley Mla7 and Mla13 genes was screened for interaction with effectors AVRA13 and AVRA7 using a high throughput yeast-two-hybrid (Y2H) assay. The Y2H screening yielded a number of clones that interacted with AVRA13 but not with AVRA7 in yeast, however, recognized both AVRA13 and AVRA7 in planta. Protein sequence analysis and mutagenesis studies identified a critical amino acid residue from MLA13 required for the interaction with AVRA13. Our study established an engineering pipeline that evolves MLA-NLRs to recognize distinct pathogen effectors, representing a major step towards made-to-order resistant crops.