7dv8
The crystal structure of rice immune receptor RGA5-HMA2.
Structural highlights
FunctionRGA5R_ORYSJ Disease resistance (R) protein that recognizes the AVR-Pia and AVR1-CO39 effector avirulence proteins from M.oryzae. Resistance proteins guard the plant against pathogens that contain an appropriate avirulence protein via an indirect interaction with this avirulence protein. That triggers a defense system including the hypersensitive response, which restricts the pathogen growth. Contribution of RGA4 is required to recognize the effector avirulence proteins AVR-Pia and AVR1-CO39 from M.oryzae (PubMed:21251109, PubMed:23548743). Acts as a repressor of the RGA4-mediated cell death activation. Upon infection, recognition and binding of the AVR effectors relieve the RGA5-mediated repression and triggers the hypersensitive response (PubMed:25024433). Immune response triggered by the RGA4-RGA5 -mediated recognition of AVR1-CO39 confers resistance to X.oryzae pathovars (PubMed:27289079).[1] [2] [3] [4] Publication Abstract from PubMedPlant nucleotide-binding and leucine-rich repeat (NLR) receptors recognize avirulence effectors directly through their integrated domains (IDs) or indirectly via the effector-targeted proteins. Previous studies have succeeded in generating designer NLR receptors with new recognition profiles by engineering IDs or targeted proteins based on prior knowledge of their interactions with the effectors. However, it is yet a challenge to design a new plant receptor capable of recognizing effectors that function by unknown mechanisms. Several rice NLR immune receptors, including RGA5, possess an integrated heavy metal-associated (HMA) domain that recognizes corresponding Magnaporthe oryzae Avrs and ToxB-like (MAX) effectors in the rice blast fungus. Here, we report a designer rice NLR receptor RGA5(HMA2) carrying an engineered, integrated HMA domain (RGA5-HMA2) that can recognize the noncorresponding MAX effector AvrPib and confers the RGA4-dependent resistance to the M. oryzae isolates expressing AvrPib, which originally triggers the Pib-mediated blast resistance via unknown mechanisms. The RGA5-HMA2 domain is contrived based on the high structural similarity of AvrPib with two MAX effectors, AVR-Pia and AVR1-CO39, recognized by cognate RGA5-HMA, the binding interface between AVR1-CO39 and RGA5-HMA, and the distinct surface charge of AvrPib and RAG5-HMA. This work demonstrates that rice NLR receptors with the HMA domain can be engineered to confer resistance to the M. oryzae isolates noncorresponding but structurally similar MAX effectors, which manifest cognate NLR receptor-mediated resistance with unknown mechanisms. Our study also provides a practical approach for developing rice multilines and broad race spectrum-resistant cultivars by introducing a series of engineered NLR receptors. A designer rice NLR immune receptor confers resistance to the rice blast fungus carrying noncorresponding avirulence effectors.,Liu Y, Zhang X, Yuan G, Wang D, Zheng Y, Ma M, Guo L, Bhadauria V, Peng YL, Liu J Proc Natl Acad Sci U S A. 2021 Nov 2;118(44). pii: 2110751118. doi:, 10.1073/pnas.2110751118. PMID:34702740[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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