Molecular and metabolic drivers of oil quality and bioenergy potential in Jatropha curcas.

Abstract

Main conclusion: Combining biochemical, molecular, and multivariate analyses identified candidate signatures and L10P41 as a promising bioenergy ideotype, supporting targeted selection for oil quality and bioenergy performance in Jatropha curcas. Jatropha curcas L. is a promising bioenergy crop, but its genetic improvement requires a deeper understanding of the molecular and metabolic factors underlying variation in oil quality, fatty acid (FA) composition, and phorbol ester (PE) accumulation. We characterized FA composition during seed development and evaluated mature-seed oil content, PE concentration, higher heating value (HHV), and the expression of KASIII, MFP2, and JcBAHD-AT in 12 contrasting elite breeding genotypes. Stage-specific principal component analysis (PCA), complemented by hierarchical cluster analysis (HCA), revealed developmentally dynamic variation in FA composition and genotype relationships. Comparison with biochemical and expression data indicated associations among lipid composition, candidate-gene expression, PE concentration, and energy performance. The L10P41 genotype combined an oleic acid-enriched profile, relatively high oil content, elevated HHV, and distinct KASIII and MFP2 expression patterns, emerging as a promising bioenergy ideotype. Variation in HHV among genotypes, including relatively high values in some genotypes with comparatively low oil content, indicated that energy performance cannot be inferred from total oil content alone and may also be associated with differences in oil composition. The putative BAHD acyltransferase gene JcBAHD-AT exhibited genotype- and stage-specific expression patterns consistent with a potential role in specialized diterpenoid metabolism; however, its relationship with PE accumulation remains associative and requires functional validation. Genotypes combining high oil content with comparatively low PE concentrations further indicated that these traits can coexist and are not necessarily tightly coupled. Overall, integrating molecular, biochemical, and multivariate analyses revealed candidate signatures associated with oil quality and bioenergy potential, advancing the identification of promising genotypes for targeted selection and precision breeding in J. curcas.