Repertoire of SSRs in the Castor Bean Genome and Their Utilization in Genetic Diversity Analysis in Jatropha curcas

Castor bean andJatrophacontain seed oil of industrial importance, share taxonomical and biochemical similarities, which can be explored for identifying SSRs in the whole genome sequence of castor bean and utilized inJatropha curcas. Whole genome analysis of castor bean identified 5,80,986 SSRs with a frequency of 1 per 680 bp. Genomic distribution of SSRs revealed that 27% were present in the non-genic region whereas 73% were also present in the putative genic regions with 26% in 5′UTRs, 25% in introns, 16% in 3′UTRs and 6% in the exons. Dinucleotide repeats were more frequent in introns, 5′UTRs and 3′UTRs whereas trinucleotide repeats were predominant in the exons. The transferability of randomly selected 302 SSRs, from castor bean to 49J. curcasgenotypes and 8Jatrophaspecies other thanJ. curcas, showed that 211 (~70%) amplified onJatrophaout of which 7.58% showed polymorphisms inJ. curcasgenotypes and 12.32% inJatrophaspecies. The higher rate of transferability of SSR markers from castor bean toJatrophacoupled with a good level of PIC (polymorphic information content) value (0.2 inJ. curcasgenotypes and 0.6 inJatrophaspecies) suggested that SSRs would be useful in germplasm analysis, linkage mapping, diversity studies and phylogenetic relationships, and so forth, inJ. curcasas well as otherJatrophaspecies.