title: Cloning of the Arabidopsis rwm1 gene for resistance to Watermelon mosaic virus points to a new function for natural virus resistance genes.
abstract: Arabidopsis thaliana represents a valuable and efficient model to understand mechanisms underlying plant susceptibility to viral diseases. Here, we describe the identification and molecular cloning of a new gene responsible for recessive resistance to several isolates of Watermelon mosaic virus (WMV, genus Potyvirus) in the Arabidopsis Cvi-0 accession. rwm1 acts at an early stage of infection by impairing viral accumulation in initially infected leaf tissues. Map-based cloning delimited rwm1 on chromosome 1 in a 114-kb region containing 30 annotated genes. Positional and functional candidate gene analysis suggested that rwm1 encodes cPGK2 (At1g56190), an evolutionary conserved nucleus-encoded chloroplast phosphoglycerate kinase with a key role in cell metabolism. Comparative sequence analysis indicates that a single amino acid substitution (S78G) in the N-terminal domain of cPGK2 is involved in rwm1-mediated resistance. This mutation may have functional consequences because it targets a highly conserved residue, affects a putative phosphorylation site and occurs within a predicted nuclear localization signal. Transgenic complementation in Arabidopsis together with virus-induced gene silencing in Nicotiana benthamiana confirmed that cPGK2 corresponds to rwm1 and that the protein is required for efficient WMV infection. This work uncovers new insight into natural plant resistance mechanisms that may provide interesting opportunities for the genetic control of plant virus diseases.
authors.affiliation: Genetics and Breeding of Fruits and Vegetables, INRA-UR1052, Dom. St Maurice, CS 60094, F-84143, Montfavet Cedex, France.
authors.forename: Laurence
authors.initials: L
authors.lastname: Ouibrahim
authors.forename: Marianne
authors.initials: M
authors.lastname: Mazier
authors.forename: Joan
authors.initials: J
authors.lastname: Estevan
authors.forename: Gaëlle
authors.initials: G
authors.lastname: Pagny
authors.forename: Véronique
authors.initials: V
authors.lastname: Decroocq
authors.forename: Cécile
authors.initials: C
authors.lastname: Desbiez
authors.forename: André
authors.initials: A
authors.lastname: Moretti
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Gallois
authors.forename: Carole
authors.initials: C
authors.lastname: Caranta
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics* / Q000276:immunology / Q000821:virology; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D002736:Chloroplasts / Q000201:enzymology; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D018744:DNA, Plant / Q000737:chemistry / Q000235:genetics; D060467:Disease Resistance / Q000235:genetics*; D008969:Molecular Sequence Data; D020125:Mutation, Missense; D010641:Phenotype; D010735:Phosphoglycerate Kinase / Q000235:genetics* / Q000378:metabolism; D010935:Plant Diseases / Q000276:immunology* / Q000821:virology; D018515:Plant Leaves / Q000201:enzymology / Q000235:genetics / Q000276:immunology / Q000821:virology; D010942:Plant Viruses / Q000502:physiology; D030821:Plants, Genetically Modified; D017800:Potyvirus / Q000502:physiology*; D036226:Seedlings / Q000201:enzymology / Q000235:genetics / Q000276:immunology / Q000821:virology; D017422:Sequence Analysis, DNA
chemical_list: D029681:Arabidopsis Proteins; D018744:DNA, Plant; D010735:Phosphoglycerate Kinase
keywords: Arabidopsis; Potyvirus; Watermelon mosaic virus; phosphoglycerate kinase; resistance gene