Submitted to: Journal of Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/22/1999
Publication Date: N/A
Interpretive Summary: Interspecific somatic hybridization, the fusing of single cells from different species of plants, can provide a means for bypassing sexual incompatibilities between the species. It is particularly useful when a wild species has a potentially useful disease resistance. Somatic hybrids between potato and Solanum bulbocastanum, a wild Mexican species, are highly resistant to late blight, caused by the fungus Phytophthora infestans. Utilizing molecular markers we have found that the genes for resistance to late blight lie on chromosome 8 of S. bulbocastanum. This finding will greatly aid our efforts to clone the responsible genes. Ultimately, such cloned gene could be introduced into susceptible cultivars to provide resistance to the disease and to obviate the necessity for spraying with fungicides. Eliminating the deliterious import of the pesticides will provide substantial relief in terms of cost of production and harmfulness to the environment.
Technical Abstract: Somatic hybrids between potato and Solanum bulbocastanum, a wild diploid (2n=2x =24) Mexican species, are highly resistant to late blight, caused by Phytophthora infestans. Both randomly amplified polymorphic DNA (RAPD) and restriction fragment length polymorphism (RFLP) markers that are closely linked to the resistance have been noted by analysis of three different backcross 2 populations derived from 2 different somatic hybrids. With reference to previously published potato and tomato maps, resistance appears to be on the long arm of chromosome 8 and is flanked by RFLP markers CP53 and CT64. In a population of BC2 plants derived from a cross between the BC1 line J10lK6 [(S. tuberosum PI 203900 + S. bulbocastanum PI 243510)x Katahdin)] x Atlantic, late blight resistance cosegregated with RFLP marker CT88 and RAPD marker OPG02-625.