Submitted to: Molecular and General Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/23/2001
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 (such as Solanum bulbocastanum in this case) has a potentially useful disease resistance such as resistance to late blight. For further development of breeding lines and for subsequent attempts and mapping and cloning the resistance it is essential to determine if the chromosomes of the various species can be detected within the hybrid. Also, it is necessary to develop specific markers for each of the wild species chromosomes so that the course of incorporation of DNA from the wild species can be followed. In this paper the necessary molecular map has been developed for Solanum bulbocastanum, the wild Mexican late blight resistant species utilized to capture the resistance. These results will now permit accurate mapping of resistance genes, a prerequisite for isolating the resistance gene. Isolation of the gene will provide a new, highly durable source of resistance to late blight.
Technical Abstract: Somatic hybrids have been obtained between potato and Solanum bulbocastanum PI 245310, a Mexican diploid (2n=2x=24) species. Through restriction fragment length polymorphism (RFLP) and randomly amplified polymorphic DNA (RAPD) analyses it was found that the somatic hybrids contain each chromosome of the diploid parent and that the synteny of RFLP markers noted with tomato, potato and S. brevidens is largely maintained in S. bulbocastanum. RFLP analyses of backcross 1 progeny of two different hybrids indicated that a substantial number of markers were either lost or were heterozygous, in marked contrast with results previously noted with S. brevidens. A RAPD map for all 12 chromosomes of S. bulbocastanum was prepared and marker transmission was followed in three second backcross populations. Results with chromosomes 3, 8 and 10 from these populations are compared.