Characterization of microsatellite markers in peach [Prunus persica (L.) Batsch]

Microsatellites have emerged as an important system of molecular markers. W e evaluated the potential of microsatellites for use in genetic studies of peach [Prunus persica (L.) Batsch]. Microsatellite loci in peach were ident ified by screening a pUC8 genomic library, a lambda ZAPII leaf cDNA library , as well as through database searches. Primer sequences for the microsatel lite loci were tested from the related Rosaceae species apple (Malusxdomest ica) and sour cherry (Prunus cerasus L.). The genomic library was screened for CT, CA and AGG repeats, while the cDNA library was screened for (CT)(n) - and (CA)(n)-containing clones. Estimates of microsatellite frequencies we re determined from the genomic library screening, and indicate that CT repe nts occur every 100 kb, CA repeats every 420 kb, and AGG repeats every 700 kb in the peach genome. Microsatellite-containing clones were sequenced, an d specific PCR primers were designed to amplify the microsatellite-containi ng regions from genomic DNA. The level of microsatellite polymorphism was e valuated among 28 scion peach cultivars which displayed one to four alleles per primer pair. Five microsatellites were found to segregate in intraspec ific peach-mapping crosses. In addition, these microsatellite markers were tested for their utility in cross-species amplification for use in comparat ive mapping both within the Rosaceae, and with the unrelated species Arabid opsis thaliana L.