Inter and intra-population variability of Jatropha curcas (L.) characterized by RAPD and ISSR markers and development of population-specific SCAR markers

Abstract

Jatropha curcas (Euphorbiaceae) is an oil-bearing species with multiple uses and considerable potential as a bioenergy crop. The present investigation has been undertaken to assess the extent of genetic diversity in a representative set of 42 accessions of J. curcas encompassing different crop growing regions in India along with a non-toxic genotype from Mexico as a prelude for utilization of promising and genetically divergent materials in the breeding programmes. Molecular polymorphism was 42.0% with 400 RAPD primers and 33.5% with 100 ISSR primers between accessions indicating modest levels of genetic variation in the Indian germplasm. The withinpopulation variation based on RAPD polymorphism was 64.0% and was on par with the inter-population variation. Polymorphic ISSR markers have been identified that could differentiate the Indian accessions from the Mexican genotype and two of them were converted to SCAR markers. The SCAR primer pair ISPJ1 amplified a 543 bp fragment in all the Indian populations, while ISPJ2 with a specific amplicon of 1,096 bp was specific to the Mexican genotype. Population-specific bands have been identified for the accession from Kerala (2 RAPD markers), Neemuch-1 from Rajasthan (1 each of RAPD and ISSR markers) and the non-toxic genotype from Mexico (17 RAPD and 4 ISSR markers), which serve as diagnostic markers in genotyping. The study indicates an immediate need for widening the genetic base of J. curcas germplasm through introduction of accessions with broader geographical background.

Molecular Characterization of Jatropha curcas Resources and Identification of Population-Specific Markers

“…A very high Fig. 4 Alignment of the microsatellite regions of 14 genotypes at the Jc03 locus showing the insertion of (GT) 4 in Cuba and Cape Verde genotypes Fig. 5 High-resolution melting analysis of BRAC6, S1C4, S2-8, M1-1, CBA2, CBB4, CBC1, CBC3, CBD8, and CVB8 genotypes (the origin of an individual is indicated with the first one or two letters in its name where CB = Cuba, CV = Cape Verde, BR = Brazil, M = Mozambique, and S = Senegal) using primers designed from Jcps9 locus.…”

“…An 18-bp M13 tail was attached to each forward primer. A Curcin-P2 PP, specific for the promoter region of the curcin gene, and a SCAR PP, ISPJ1, presumed to be associated with the toxicity trait [4,5], were also included in this study. A BLAST analysis of sequences, from which PPs were designed, was performed (http://www.ncbi.nlm.nih.gov/ projects/mapview/static/MVPlantBlast.shtml?10, accessed on Nov. 15,2009) to identify similarity with the sequences of model plant species.…”

“…Some parts of the plant and seeds have curative properties against human diseases [12]. Due to the presence of phorbol esters, Jatropha is generally considered toxic; however, some non-toxic genotypes exist in Central America [4,5,18,19].…”

“…Several studies on genetic variability in Jatropha populations were reported using different molecular markers, e.g., amplified fragment length polymorphism, randomly amplified polymorphic DNA (RAPD), single primer amplification reaction, inter-simple sequence repeat (ISSR), and simple sequence repeat (SSR) [1,4,5,15,23,27,37]. DNA marker (RAPD, ISSR, and SSR) analyses revealed that the Jatropha seeds commercialized worldwide consisted of few genetically identical or closely related clones and showed very low genetic variation either within or between varieties [1].…”

“…A diversity analysis of 192 accessions collected throughout Brazil reflected a common ancestry, genetic drift, and intensive selection of cultivated material since its introduction [29]. Narrow genetic bases were reported among germplasms collected in India [4] and in China [37]. Wider variability was present among genotypes collected from different geographic areas [5] and between toxic and non-toxic genotypes collected in Mexico [23].…”