Genetic and physical mapping of the grapevine powdery mildew resistance gene, Run1, using a bacterial artificial chromosome library

Abstract

Resistance to grapevine powdery mildew is controlled by Run1, a single dominant gene present in the wild grapevine species, Muscadinia rotundifolia, but absent from the cultivated species, Vitis vinifera. Run1 has been introgressed into V. vinifera using a pseudo-backcross strategy, and genetic markers have previously been identified that are linked to the resistance locus. Here we describe the construction of comprehensive genetic and physical maps spanning the resistance locus that will enable future positional cloning of the resistance gene. Physical mapping was performed using a bacterial artificial chromosome (BAC) library constructed using genomic DNA extracted from a resistant V. vinifera individual carrying Run1 within an introgression. BAC contig assembly has enabled 20 new genetic markers to be identified that are closely linked to Run1, and the position of the resistance locus has been refined, locating the gene between the simple sequence repeat (SSR) marker, VMC4f3.1, and the BAC end sequence-derived marker, CB292.294. This region contains two multigene families of resistance gene analogues (RGA). A comparison of physical and genetic mapping data indicates that recombination is severely repressed in the vicinity of Run1, possibly due to divergent sequence contained within the introgressed fragment from M. rotundifolia that carries the Run1 gene.

Detection of downy and powdery mildew resistance QTL in a ‘Regent’ × ‘RedGlobe’ population

“…The first of these loci, Run1, was identified and mapped on chromosome 12 of M. rotundifolia (Pauquet et al 2001;Donald et al 2002;Merdinoglu et al 2003;Barker et al 2005). This locus was found to be closely linked to the Rpv1 locus (Merdinoglu et al 2003).…”

Behavior of grape breeding lines with distinct resistance alleles to downy mildew (Plasmopara viticola)

“…The locus Rpv1 is located on chromosome 12 of M. rotundifolia, and it is associated to locus Run1, which confers resistance to downy mildew (Barker et al 2005, Merdinoglu et al 2003. Rpv1/Run1 alleles were introduced in V. vinifera by backcrossing (Pauquet et al 2001).…”

Genetic dissection of agronomic traits within a segregating population of breeding table grapes

“…The majority of these studies have concentrated on disease resistance introgressed from native North American species (Barker et al, 2005;Riaz et al, 2008;Marguerit et al, 2009;Coleman et al, 2009). Other studies focus on developing genetic maps and identifying QTL for agronomic traits such as seedlessness, berry size, fruit ripening, fruit quality, and cluster structure (Doligez et al, 2002;Fanizza et al, 2005;Mejía et al, 2007).…”