Submitted to: American Journal of Potato Research
Publication Type: Abstract Only
Publication Acceptance Date: 3/15/2006
Publication Date: 1/15/2007
Citation: Zhang, L., Mojtahedi, H., Kuang, H., Baker, B., Brown, C.R. 2007. Fine Mapping and Isolation of Rmc1(blb)Locus to Columbia Root-Knot Nematode Resistance from Solanum bulbocastanum. American Journal of Potato Research. 84: 123.
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. The natural resistance has been discovered in several wild potato species, Solanum bulbocastanum, S. hougasii and S. fendleri, endemic to Mexico and the Southwest United States. A gene, RMc1(blb), controlling resistance derived from S. bulbocastanum has located on the distal end of Chromosome 11. In addition to two AFLP markers and two CAPS markers were localized close to the gene with at least 0.5 cM genetic distance, five STS markers linked with N-like sequences from another Mexican wild species S. demissum co-segregated with the RMc1(blb) locus. Some of these STS markers amplified in Mexican and North American wild species, but not in South American wild species. We have constructed several BAC contigs containing the potential candidate N homologous genes from the S. demissum BAC library. Three BACs from these contigs have been sequenced. At the same time, a set of S. bulbocastanum BAC clones derived from the susceptible parent, PT29, were also identified. The identified BAC clones are in progress for BAC fingerprinting to construct a physical map of the target region for the susceptible haplotype. It will provide the foundation for eventual cloning; and shed light on the nature of N-like genes in potato and help establish a syntenic region from comparison of S. demissum and S. bulbocastanum.