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Concurrent Session

Session: Concurrent Session: Structure Informed Synthetic Biology: From Design to Function

Integrated domains in cereal tandem kinase protein immune receptors are novel targets for disease resistance engineering

Thursday, July 17, 2025
15:15 - 15:35  
Location: Confex Hall 1+2

Abstract Text:

Magnaporthe oryzae causes blast disease on economically important cereal crops. During infection, the pathogen secretes effectors, with a subset targeting plant heavy metal-associated (HMA) domain proteins. To counteract pathogen infection, cereal crops have evolved intracellular immune receptors containing integrated HMA domains to bait effectors. Recently, integrated HMAs have been discovered in Tandem Kinase Proteins (TKPs), an emergent immune receptor class in cereal crops. Barley Rmo2 and wheat Rwt7 are HMA-containing TKPs that specifically recognise the M. oryzae effectors, PBY2 and PWT7, respectively. Using biochemical and structural approaches, we demonstrate that the HMA domains from these TKPs specifically bind to PBY2 or PWT7 with high affinities. Structural-led mutagenesis of effectors disrupted HMA binding in vitro and TKP-based recognition in planta. HMA domain swaps between Rmo2 and Rwt7 receptors facilitated a switch in recognition specificity. These data show that the HMA domain is sufficient for recognition specificity in these receptors. To explore the potential of expanding recognition profiles of TKP receptors, we engineered a HMA domain to bind both PBY2 and PWT7 in vitro and validated the gain-of-binding structurally. Incorporating the engineered HMA in an Rmo2 chassis retained recognition of PBY2 and gained recognition of PWT7. This work highlights the potential of engineering integrated domains within TKP receptors for novel recognition specificities.