Over-expression of CYP78A98, a cytochrome P450 gene from Jatropha curcas L, increases seed size of transgenic tobacco

Background: Jatropha curcas L. (further referred to as Jatropha), as a rapidly emerging biofuel crop, has attracted worldwide interest. However, Jatropha is still an undomesticated plant, the true potential of this shrub has not yet been fully realized. To explore the potential of Jatropha, breeding and domestication are needed. Seed size is one of the most important traits of seed yield and has been selected since the beginning of agriculture. Increasing the seed size is a main goal of Jatropha domestication for increasing the seed yield, but the genetic regulation of seed size in Jatropha has not been fully understood. Results: We cloned CYP78A98 gene from Jatropha,a homologue of CYP78A5 in Arabidopsis.Wefound that CYP78A98 was highly expressed in male flower, female flower, stem apex, leaf and developing seed. However, its transcripts were hardly detected in root and stem. CYP78A98 protein localized in endoplasmic reticulum (ER) and the hydrophobic domain at the N-terminus was essential for the correct protein localization. Furthermore, INNER NO OUTER promoter (pINO) drove specific overexpression of CYP78A98 in transgenic tobacco seeds resulted in increased seed size and weight, as well as improved seed protein and fatty acid content. Conclusions: The results indicated that CYP78A98 played a role in Jatropha seed size control. This may help us to better understand the genetic regulation of Jatropha seed development, and accelerate the breeding progress of Jatropha.

A novel chloroplastic isopentenyl diphosphate isomerase gene from Jatropha curcas: Cloning, characterization and subcellular localization

Background Jatropha curcas is a rich reservoir of pharmaceutically active terpenoids. More than 25 terpenoids have been isolated from this plant, and their activities are anti-bacterial, anti-fungal, anti-cancer, insecticidal, rodenticidal, cytotoxic and molluscicidal. But not much is known about the pathway involved in the biosynthesis of terpenoids. The present investigation describes the cloning, characterization and subcellular localization of isopentenyl diphosphate isomerase (IPI) gene from J. curcas. IPI is one of the rate limiting enzymes in the biosynthesis of terpenoids, catalyzing the crucial interconversion of isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP). Results A full-length JcIPI cDNA consisting of 1355 bp was cloned. It encoded a protein of 305 amino acids. Analysis of deduced amino acid sequence predicted the presence of conserved active sites, metal binding sites and the NUDIX motif, which were consistent with other IPIs. Phylogenetic analysis indicated a significant evolutionary relatedness with Ricinus communis. Southern blot analysis showed the presence of an IPI multigene family in J. curcas. Comparative expression analysis of tissue specific JcIPI demonstrated the highest transcript level in flowers. Abiotic factors could induce the expression of JcIPI. Subcellular distribution showed that JcIPI was localized in chloroplasts. Conclusion This is the first report of cloning and characterization of IPI from J. curcas. Our study will be of significant interest to understanding the regulatory role of IPI in the biosynthesis of terpenoids, although its function still needs further confirmation.