Authors: C L Barker T Donald J Pauquet M B Ratnaparkhe A Bouquet AF AdamBlondon M R Thomas I Dry
Publish Date: 2005/05/18
Volume: 111, Issue: 2, Pages: 370-377
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 pseudobackcross 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 VMC4f31 and the BAC end sequencederived marker CB292294 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 geneThis work was supported in part by the Commonwealth Cooperative Research Centre Program and specifically by the Cooperative Research Centre for Viticulture CRCV and the Grape and Wine Research and Development Corporation GWRDC The authors would like to acknowledge the excellent technical assistance of A Jermakow K Swann N Tikhomirov and Y Bertrand
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