PCR-RFLP analysis of chloroplast gene regions in Cajanus (Leguminosae) and allied genera

Twenty-eight species belonging to five genera of the sub tribe Cajaninae; viz., Cajanus (15 species), Rhynchosia (10 species), Dunbaria, Flemingia and Paracalyx were analysed for variations in four chloroplast gene regions, rbcL, trnS-psbC, 16S and trnL-UAA. The four chloroplast gene regions were amplified with specific primers and subsequently digested with 15 restriction enzymes. Rhynchosia did not show any inter-specific differences in the four gene regions for any of the enzymes used. In Cajanus, the inter-specific PCR-RFLP profile of the four gene regions for all the enzymes were similar except for the Pst I digests of trnS-psbC gene region. At inter-generic level, rbcL gene region did not show polymorphism with any of the enzymes used; while in trnS-psbC gene region polymorphism was observed only with Pst I and Hae III digestions. Inter-generic PCR-RFLP of 16S did not reveal any variation. The trnL-UAA gene region had restriction site only for EcoR I in which Cajanus and Rhynchosia showed similar profiles while Dunbaria showed a different profile. The trnL-UAA gene region in Paracalyx and Flemingia did not have restriction site for this enzyme. Despite the analyses of four gene regions using 15 restriction enzymes, differentiation at genus level could not be obtained. These observations indicated limited divergence of the chloroplast genome among the four genera of the sub-tribe Cajaninae suggesting close relationships of the taxa.