Identification of molecular markers associated with leptine production in a population of Solanum chacoense Bitter

Abstract

  Solanum chacoense Bitter, a wild relative of the cultivated potato, produces several glycoalkaloids, including solanine, chaconine, and the leptines. The foliar-specific leptine glycoalkaloids are believed to confer resistance to the Colorado Potato Beetle (CPB). Using two bulked DNA samples composed of high- and low-percent leptine individuals from a segregating F₁ population of S. chacoense, we have identified two molecular markers that are closely linked to high percent solanine+chaconine and, conversely, to nil/low percent leptine. One of these, a 1,500-bp RAPD product (UBC370-1500), had a recombination value of 3% in the F₁ progeny, indicating tight linkage. UBC370-1500 mapped to the end of the short arm of potato chromosome 1, in the region of a previously mapped major QTL for solanidine, from a S. tuberosum (solanidine)×S. berthaultii (solasodine) cross. Taken together, these results suggest that either (1) a major locus determining solanidine accumulation in Solanum spp. is on chromosome 1 in the region defined by the RFLP markers TG24, CT197, and CT233, or (2) this region of chromosome 1 may harbor two or more important genes which determine accumulation of steroidal aglycones. These findings are important for the genetics of leptine (as well as other glycoalkaloid) accumulation and for the development of CPB-resistant potato varieties.