Quantitative disease resistance to the bacterial pathogen X anthomonas campestris involves an A rabidopsis immune receptor pair and a gene of unknown function

• Published in: Molecular plant pathology 2016-05, Vol.17 (4), p.510-520
• Main Authors: Debieu, Marilyne, Huard‐Chauveau, Carine, Genissel, Anne, Roux, Fabrice, Roby, Dominique
• Format: Article
• Language: English
• ISSN: 1464-6722; 1364-3703
• DOI: 10.1111/mpp.12298

Although quantitative disease resistance ( QDR ) is a durable and broad‐spectrum form of resistance in plants, the identification of the genes underlying QDR is still in its infancy. RKS 1 ( Resistance related   K ina S e1 ) has been reported recently to confer QDR in A rabidopsis thaliana to most but not all races of the bacterial pathogen X anthomonas campestris pv. campestris ( X cc ). We therefore explored the genetic bases of QDR in A . thaliana to diverse races of X . campestris ( X c ). A nested genome‐wide association mapping approach was used to finely map the genomic regions associated with QDR to X cc12824 (race 2) and X cc CFBP 6943 (race 6). To identify the gene(s) implicated in QDR , insertional mutants (T‐ DNA ) were selected for the candidate genes and phenotyped in response to X c . We identified two major QTLs that confer resistance specifically to Xcc12824 and XccCFBP6943 . Although QDR to X cc12824 is conferred by At5g22540 encoding for a protein of unknown function, QDR to X cc CFBP 6943 involves the well‐known immune receptor pair RRS 1/ RPS 4. In addition to RKS 1 , this study reveals that three genes are involved in resistance to X c with strikingly different ranges of specificity, suggesting that QDR to X c involves a complex network integrating multiple response pathways triggered by distinct pathogen molecular determinants.