Jatropha curcas oil body proteome and oleosins: L-form JcOle3 as a potential phylogenetic marker

The seed oil of Jatropha curcas has been proposed as a source of biodiesel. In plants, seed oil is stored in subcellular organelles called oil bodies (OBs), which are stabilized by proteins. Proteome composition of the J. curcas OBs revealed oleosins as the major component and additional proteins similar to those in other oil seed plants. Three J. curcas oleosins were isolated and characterized at the gene, transcript and protein level. They all contained the characteristic proline knot domain and were each present as a single copy in the genome. The smallest, L-form JcOle3 contained an intron. Isolation of its promoter revealed seed-specific cis-regulatory motifs among others. Spatio-temporal transcript expression of J. curcas oleosins was largely similar to that in other oil seed plants. Immunoassay with antibodies against an Arabidopsis oleosin or against JcOle3, on seed proteins extracted by different approaches, revealed JcOle3 oligomers. Alleles of JcOle3 and single nucleotide polymorphisms (SNPs) in its intron were identified in J. curcas accessions, species and hybrids. Identified alleles and SNPs could serve as markers in phylogenetic or breeding studies.