Abstract
The genus Ipomoea (Convolvulaceae) has a sporophytic self-incompatibility system that is controlled by a single multiallelic S-locus. Self-incompatibility reactions of Ipomoea occur on the stigma surface at an early stage of self-pollination, resulting in the complete arrest of pollen germination. To identify the S-locus genes, a fine linkage map of DNA markers was constracted around the S-locus. From the linkage analysis, the S-locus region was estimated to be defined within 0.1 cM. Screening and alignment of BAC clones revealed that the S-locus region is located within ca. 250 kbp. Shot-gun sequencing of the BAC clones showed several ORFs in the S-locus region. From Northern blot analyses, some genes were found to be specifically expressed in the stigma and/or pollen.
