Mining and charactering microsatellites in Cucumis melo expressed sequence tags from sequence database

Simple sequence repeats (SSRs) derived from expressed sequence tags (ESTs) are valuable markers because they represent transcribed regions and often have putative functions. We mined and characterized microsatellites in melon ESTs. Three hundred and eighty-three SSR loci were identified in 309 of 3188 unigenes assembled by 5747 EST and mRNA sequences in GenBank with occurring frequency of 1/4.7 kb. Twenty-two polymorphic EST-SSR markers were developed with the mean allele number of 2.9 per locus and mean expected heterozygosity of 0.442. Amplification products were also detected by 15 pairs of primer in Cucumis sativus. Those informative EST-SSR markers can be used in melon genetic improvement projects.