Submitted to: Plant and Animal Genome VX Conference Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 10/31/2004
Publication Date: 1/15/2005
Citation: Zhang, L., Mojtahedi, H., Yang, C., Culley, D., Brown, C.R. 2005. Fine mapping of the Columbia root-rot nematode resistance gene R Mc1(b1b) from Solanum bulbocastanum. Plant and Animal Genome XIII Conference Abstracts. p 194 (P492).
Technical Abstract: The Columbia root-knot nematode (Meloidogyne chitwoodi) causes a severe disease on potato in the Northwest of the US and other parts of the World. A gene, RMc1(blb), controlling resistance derived from the Mexican wild species Solanum bulbocastanum has been identified and used in breeding resistant germplasms. The goal of this study is to find closely linked molecular markers leading to the isolation of the resistance gene. A F1 mapping population with over 250 individuals generated from a intraspecific cross between SB22, a root-knot resistant clone, and PT29, a susceptible clone, was used for marker screening and genetic linkage analysis. So far, four markers (2 AFLP markers and 2 specific CAPS markers), closely linked to RMc1(blb), were found through bulk segregant analysis . Two AFLP markers, EAGGMCTA and EAGGMCTT were linked at 0.5 cM and 1.0 cM distance, respectively. Two specific CAPS markers, M33 and M39 on the upper arm of Chromosome 11, originally developed for fine mapping resistance to potato virus Y, were localized close to the gene with 2.4 cM and 3.8 cM distance, respectively. These four markers have been sequenced, and converted into simple PCR markers. These markers will be used as probes to screen an available BAC library derived from PT29 to generate more markers by chromosome walking toward the RMc1(blb) gene. Furthermore, these new PCR-based markers have provided an efficient alternative for screening large breeding populations for the Columbia root-knot nematode resistance.