Oil rich seeds of Jatropha curcas as a renewable source of biodiesel: genotyping clones of cultivated varieties and cloning genes for fatty acid biosynthesis

Jatropha is becoming a popular non-food oleaginous crop in several developing countries for its proposed value for the production of bioenergy. Despite the great potentials of its oil-rich seeds as renewable source of biofuel and the broad interest toward large-scale plantations, relatively little is known with respect to population genetics and functional genomics. We have performed SSR marker analysis to gain new insights on the genetic diversity structure of 123 multiple accessions, and the genetic relationships among commercial clones and locally dominant ecotypes. Based on our findings, seeds commercialized worldwide seem to include a few closely related genotypes that show a very low differentiation among cultivars. In addition, we have cloned and characterized 12 genes that control key steps of FA biosynthesis for a better understanding of the polymorphism information content of their allelic variants. The sequencing of these genes was pursued for discovering a set of discriminant SNPs and for haplotyping a core collection of accessions. Gene expression levels were also determined in two distinct developmentally staged seeds by means of quantitative Real-Time PCR assays. The genetical and functional analysis of seed-specific fatty acid desaturases (FAD/SAD) is the first step for selecting or generating high-oleate J. curcas genotypes, and also for breeding oil-rich J. curcas cultivars suitable for biofuel production.