Submitted to: Plant Genome Analysis Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 12/10/2003
Publication Date: 1/15/2004
Citation: Norby, M.J., Havey, M.J. 2004. Comparative mapping of late-blight resistance loci in solanum. Plant Genome Analysis Abstracts. Interpretive Summary:
Technical Abstract: Phytophthora infestans is the casual agent of late blight and continues to be a major threat to potato production worldwide. There are no curative control agents available and resistance genes offer promise in controlling late-blight epidemics. To date, the sole source of late-blight resistance has been from 6x[4 Endosperm Balance Number (EBN)] Solanum demissum. Mexican 2x(1EBN) Solanum species possess a wealth of late-blight resistances, but have been neglected due to crossing barriers. Crossing schemes manipulating EBN and ploidies allow for the efficient integration of 2x(1EBN) germplasm into cultivated potato. Comparative mapping also demonstrated synteny between 2x(1EBN) Solanum species and potato. Isolate MSU96 (US8/A2) of P. infestans revealed a late-blight resistance locus (Rpi1) from 2x(1EBN) S. pinnatisectum (PI 253214) that mapped to chromosome seven (MGG 265:977-985). MSU96 was avirulent on the late-blight differential R9-Hodgson 2573 (LB3), revealing the presence of an avirulence gene for R9, which originated from S. demissum. To test the relationship between late-blight resistances in 2x(1EBN) S. pinnatisectum (PI 253214) and 6x(4EBN) S. demissum, we are evaluating an F1 segregating family for late blight with detached leaf assays and molecular markers on chromosome seven. Synteny between late-blight resistance loci from Solanum species of disparate ploidies and EBNs will facilitate the identification of unique resistance alleles and loci.