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ARS Home » Midwest Area » St. Paul, Minnesota » Cereal Disease Lab » Research » Publications at this Location » Publication #417331
Research Project: Surveillance, Pathogen Biology, and Host Resistance of Cereal Rusts

Location: Cereal Disease Lab

Title: Molecular mimicry of a pathogen virulence target by a plant immune receptor

Author
item GOMEZ DE LA CRUZ, DIANA - Sainsbury Laboratory
item ZDRZALEK, RAFAL - John Innes Center
item BANFIELD, MARK - John Innes Center
item TALBOT, N - Sainsbury Laboratory
item Moscou, Matthew

Submitted to: bioRxiv
Publication Type: Pre-print Publication
Publication Acceptance Date: 7/26/2024
Publication Date: 7/26/2024
Citation: Gomez De La Cruz, D., Zdrzalek, R., Banfield, M.J., Talbot, N.J., Moscou, M.J. 2024. Molecular mimicry of a pathogen virulence target by a plant immune receptor. bioRxiv. https://doi.org/10.1101/2024.07.26.605320.
DOI: https://doi.org/10.1101/2024.07.26.605320

Interpretive Summary: Plants are constantly defending themselves against pathogens. During the infection process, plant pathogens secrete proteins that help to access nutrients and compromise the plant immune system. In turn, plants carry immune receptors that can recognize these proteins in order to mount a defense response. While many plant immune receptors have been identified, the process of how they emerge remains unclear. In this work, we discovered that a plant immune receptor (MLA3) can gain the ability to recognize a pathogen protein (PWL2) by mimicking the structure of its original plant target (HIPP43). We show how this knowledge can be applied to engineer new recognition in a different plant immune receptor (SR50). These results reveal a new approach to enhancing disease resistance in plants.

Technical Abstract: Plants and animals respond to pathogen attack by mounting innate 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 receptors evolve new recognition specificities remain poorly understood. Here we report that a plant NLR has evolved the capacity 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 has acquired the capacity to bind and respond to Pwl2 through molecular mimicry of the effector host target, HIPP43. We demonstrate that the amino acids at the binding interface of MLA3 and Pwl2 are highly conserved in the binding interface of HIPP43 and are necessary to trigger an immune response. This discovery 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. Collectively, these results provide evidence that plant immune receptors have evolved sophisticated mimicry strategies to counteract pathogen attack.