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A single amino acid polymorphism in a conserved effector of the multihost blast fungus pathogen expands host-target binding spectrum

DOI: 10.1371/journal.ppat.1009957 DOI Help

Authors: Adam R. Bentham (John Innes Centre) , Yohann Petit-Houdenot (Université Paris-Saclay, INRAE, AgroParisTech, UMR BIOGER) , Joe Win (University of East Anglia) , Izumi Chuma (Obihiro University of Agriculture and Veterinary Medicine) , Ryohei Terauchi (Kyoto University) , Mark J. Banfield (John Innes Centre) , Sophien Kamoun (University of East Anglia) , Thorsten Langner (University of East Anglia)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Plos Pathogens , VOL 17

State: Published (Approved)
Published: November 2021
Diamond Proposal Number(s): 18565 , 13467

Open Access Open Access

Abstract: Accelerated gene evolution is a hallmark of pathogen adaptation and specialization following host-jumps. However, the molecular processes associated with adaptive evolution between host-specific lineages of a multihost plant pathogen remain poorly understood. In the blast fungus Magnaporthe oryzae (Syn. Pyricularia oryzae), host specialization on different grass hosts is generally associated with dynamic patterns of gain and loss of virulence effector genes that tend to define the distinct genetic lineages of this pathogen. Here, we unravelled the biochemical and structural basis of adaptive evolution of APikL2, an exceptionally conserved paralog of the well-studied rice-lineage specific effector AVR-Pik. Whereas AVR-Pik and other members of the six-gene AVR-Pik family show specific patterns of presence/absence polymorphisms between grass-specific lineages of M. oryzae, APikL2 stands out by being ubiquitously present in all blast fungus lineages from 13 different host species. Using biochemical, biophysical and structural biology methods, we show that a single aspartate to asparagine polymorphism expands the binding spectrum of APikL2 to host proteins of the heavy-metal associated (HMA) domain family. This mutation maps to one of the APikL2-HMA binding interfaces and contributes to an altered hydrogen-bonding network. By combining phylogenetic ancestral reconstruction with an analysis of the structural consequences of allelic diversification, we revealed a common mechanism of effector specialization in the AVR-Pik/APikL2 family that involves two major HMA-binding interfaces. Together, our findings provide a detailed molecular evolution and structural biology framework for diversification and adaptation of a fungal pathogen effector family following host-jumps.

Journal Keywords: Rice blast fungus; Genomics; Phylogenetic analysis; Conservation genetics; Genetic loci; Hydrogen bonding; Evolutionary adaptation; Plant pathogens

Diamond Keywords: Fungi; Cereal Crops

Subject Areas: Biology and Bio-materials, Chemistry

Instruments: I03-Macromolecular Crystallography , I04-Macromolecular Crystallography

Added On: 29/11/2021 11:46


Discipline Tags:

Evolutionary science Plant science Pathogens Biochemistry Agriculture & Fisheries Genetics Chemistry Structural biology Life Sciences & Biotech

Technical Tags:

Diffraction Macromolecular Crystallography (MX)