Plant & Animal Genome V Conference
Town & Country Hotel, San Diego, CA, January 12-16, 1997.
PAG-V: W74 - SOYBEAN SSR MARKER DEVELOPMENT - APPLICATIONS IN LEGUMES
W74
SOYBEAN SSR MARKER DEVELOPMENT - APPLICATIONS IN LEGUMES
CREGAN, PERRY B.
Soybean and Alfalfa Research Lab, USDA-ARS, Beltsville Agrucultural Research Center, Beltsville, MD 20705 USA,
Simple Sequence Repeat (SSR's) are a valuable source of genetic markers in plants, however the use of primer sets developed in one species to amplify loci in related species is poorly studied. The use of primer sets in heterologous species would provide a savings in terms of marker development and would offer the opportunity to conduct studies of comparative genome structure. It was our intent to provide initial data on the use of a diverse set of cultivated soybean derived SSR markers in other species of the genus Glycine as well as in a set of genotypes of important grain legume species. The first study involved a total of 19 Glycine accessions including cultivated and wild soybean (the putative ancestor of cultivated soybean) as well as the 17 perennial species. PCR amplification of genomic DNA of each of the 19 genotypes was attempted using primer sets to 72 SSR loci derived from cultivated soybean. The SSR core motifs included AT, CT, ATT, and CTT. Eleven of the loci were derived from GenBank sequences while the remainder were derived from genomic libraries. Fifteen loci gave products only in cultivated and wild soybean while 19 yielded amplification products in all 19 genotypes. Of these 19 loci, a disproportionately high percentage contained CT core motifs. Whether the sequences flanking CT SSRs are better conserved than those flanking other SSRs is unclear because the total sample of loci was quite small. In the study which included amplification of genomic DNA of pea, common bean, chickpea, and cowpea a relatively low proportion of soybean derived SSR loci yielded single well defined PCR products. This value was less than 10% for each of these species and suggested that only a few soybean SSR primer sets would be of any value inother grain legume species.