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Multiple variants of the fungal effector AVR-Pik bind the HMA domain of the rice protein OsHIPP19, providing a foundation to engineer plant defence

DOI: 10.1016/j.jbc.2021.100371 DOI Help

Authors: Josephine H. R. Maidment (John Innes Centre) , Marina Franceschetti (John Innes Centre) , Abbas Maqbool (John Innes Centre) , Hiromasa Saitoh (Tokyo University) , Chatchawan Jantasuriyarat (John Innes Centre; Kasetsart University; National Research University-Kasetsart University (CASTNAR, NRU-KU)) , Sophien Kamoun (University of East Anglia) , Ryohei Terauchi (Iwate Biotechnology Research Centre; Kyoto University) , Mark J. Banfield (John Innes Centre)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Journal Of Biological Chemistry , VOL 7

State: Published (Approved)
Published: February 2021
Diamond Proposal Number(s): 13467

Open Access Open Access

Abstract: Microbial plant pathogens secrete effector proteins which manipulate the host to promote infection. Effectors can be recognised by plant intracellular nucleotide-binding leucine-rich repeat (NLR) receptors, initiating an immune response. The AVR-Pik effector from the rice blast fungus Magnaporthe oryzae is recognised by a pair of rice NLR receptors, Pik-1 and Pik-2. Pik-1 contains a non-canonical integrated heavy metal-associated (HMA) domain, which directly binds AVR-Pik to activate plant defences. The host targets of AVR-Pik are also HMA domain-containing proteins, namely heavy metal-associated isoprenylated plant proteins (HIPPs) and heavy metal-associated plant proteins (HPPs). Here, we demonstrate that one of these targets interacts with a wider set of AVR-Pik variants compared to the Pik-1 HMA domains. We define the biochemical and structural basis of the interaction between AVR-Pik and OsHIPP19, and compare the interaction to that formed with the HMA domain of Pik-1. Using analytical gel filtration and surface plasmon resonance, we show that multiple AVR-Pik variants, including the stealthy variants AVR-PikC and AVR-PikF which do not interact with any characterised Pik-1 alleles, bind to OsHIPP19 with nanomolar affinity. The crystal structure of OsHIPP19 in complex with AVR-PikF reveals differences at the interface that underpin high-affinity binding of OsHIPP19-HMA to a wider set of AVR-Pik variants than achieved by the integrated HMA domain of Pik-1. Our results provide a foundation for engineering the HMA domain of Pik-1 to extend binding to currently unrecognised AVR-Pik variants and expand disease resistance in rice to divergent pathogen strains.

Journal Keywords: plant biochemistry; plant defense; protein structure; protein-protein interaction; receptor structure-function; virulence factor; Nod-like receptor (NLR)

Subject Areas: Biology and Bio-materials, Chemistry

Instruments: I03-Macromolecular Crystallography

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