The isolation of (GA)n microsatellites using a highly microsatellite-enriched library is described for the first time in common bean (Phaseolus vulgaris L.). A relatively simple and effective method to isolate DNA repeats from microsatellite-enriched libraries based on hybridization-capture of repeat regions using biotin-conjugated oligonucleotids and non-radioactive colony hybridization was carried out. PCR products from 200 to 800 bp were obtained and cloned. Of the 60 clones sequenced, 21 yielded (GA)n microsatellites with n values equal or higher than six. These (GA)n microsatellite-containing loci could be useful for further genetic mapping studies. A (GA)n microsatellite linked to a putative MADS-box gene was identified. This sequence, which represents the first MADS-box locus described to date in common bean, showed a very high similarity with other known MADS-box sequences and was grouped within the AGL2 subfamily cluster of the Arabidopsis MADS-box genes. The vicinity of microsatellites to some genes is also discussed.
Phaseolus vulgaris L.; genetic markers; microsatellites; MADS-box; transcriptional factor
