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Poster

Session: Session 1 Presenting Authors at Posters (Evens)

P-438 - Molecular mimicry of a pathogen virulence target by a plant immune receptor

Tuesday, July 15, 2025
09:55 - 11:30  
Location: Confex Hall 3
Structure Informed Synthetic Biology: From Design to Function
Plants respond to pathogen attack by mounting immune responses that require intracellular nucleotide binding leucine-rich repeat (NLR) proteins. These immune receptors detect pathogen infection by sensing virulence effector proteins. However, the mechanisms by which NLRs evolve new recognition specificities remain poorly understood. Here we report a plant NLR that has evolved the ability to bind to a pathogen effector by acting as a molecular mimic of a virulence target of the effector, thereby triggering an immune response. The barley NLR Mildew Locus A 3 (MLA3) confers resistance to the blast fungus Magnaporthe oryzae by recognizing the effector Pwl2. Using structural analysis, we show that MLA3 acquired the capacity to bind and respond to Pwl2 through molecular mimicry of the effector host target, HIPP43. This fundamental knowledge enabled us to bioengineer a chimeric receptor by introducing the Pwl2 binding interface of MLA3 into SR50, an MLA ortholog in rye that confers resistance to wheat stem rust. The engineered version of SR50 has dual recognition activities, binding and responding to effectors from two major cereal pathogens. Using transgenic lines, we aim to test whether bioengineering of SR50 results in multiple disease resistance. These results provide evidence that plant immune receptors have evolved sophisticated mimicry strategies to counteract pathogen attack and provide a framework for engineering immune receptors with multiple pathogen recognition.