MtQRRS1, an R-locus required for Medicago truncatula quantitative resistance to Ralstonia solanacearum
Article first published online: 2 MAY 2013
© 2013 The Authors. New Phytologist © 2013 New Phytologist Trust
Volume 199, Issue 3, pages 758–772, August 2013
How to Cite
Ben, C., Debellé, F., Berges, H., Bellec, A., Jardinaud, M.-F., Anson, P., Huguet, T., Gentzbittel, L. and Vailleau, F. (2013), MtQRRS1, an R-locus required for Medicago truncatula quantitative resistance to Ralstonia solanacearum. New Phytologist, 199: 758–772. doi: 10.1111/nph.12299
- Issue published online: 11 JUL 2013
- Article first published online: 2 MAY 2013
- Manuscript Accepted: 27 MAR 2013
- Manuscript Received: 1 MAR 2013
- bacterial wilt;
- Medicago truncatula ;
- quantitative trait locus (QTL);
- quantitative resistance;
- Ralstonia solanacearum ;
- root pathogen
- Ralstonia solanacearum is a major soilborne pathogen that attacks > 200 plant species, including major crops. To characterize MtQRRS1, a major quantitative trait locus (QTL) for resistance towards this bacterium in the model legume Medicago truncatula, genetic and functional approaches were combined.
- QTL analyses together with disease scoring of heterogeneous inbred families were used to define the locus. The candidate region was studied by physical mapping using a bacterial artificial chromosome (BAC) library of the resistant line, and sequencing. In planta bacterial growth measurements, grafting experiments and gene expression analysis were performed to investigate the mechanisms by which this locus confers resistance to R. solanacearum.
- The MtQRRS1 locus was localized to the same position in two recombinant inbred line populations and was narrowed down to a 64 kb region. Comparison of parental line sequences revealed 15 candidate genes with sequence polymorphisms, but no evidence of differential gene expression upon infection. A role for the hypocotyl in resistance establishment was shown.
- These data indicate that the quantitative resistance to bacterial wilt conferred by MtQRRS1, which contains a cluster of seven R genes, is shared by different accessions and may act through intralocus interactions to promote resistance.