Isolation of putative LAR (leucoanthocyanidin reductase) gene fragment differentially expressed in Jatropha curcas L. leaves

Jatropha curcas Linn. (Euphorbiaceae) is a shrub, which is widely distributed especially in tropical areas of Africa. Compounds that have been isolated from J. curcas leaves include flavonoids, sterols their glucosides and alkaloids. Many of both structural and regulatory genes included in secondary metabolite pathways have been cloned from several model plants. Leaves at four different growing stages were collected and cDNAs obtained were analyzed by PCR applying specific primers. All the reactions were performed three times and only repeatable fragments were taken into account for sequencing. Obtained sequences were compared in EMBL databases in order to identify their homology and their putative function. A total of 45 polymorphic fragments were collected. Twenty-six of them showed homology with ESTs (Expressed Sequence Tagged), while other 19 sequences showed to be homologous to genes involved in secondary metabolism and polyphenol pathways. The results obtained underline a different kinetic expression of the gene fragment isolated. They are especially expressed at different growing stage. In particular, applying LAR gene specific primers, an amplicon of 945bp was obtained. It is 98.4% homologous to the gene previously isolated in V. vinifera leaves. These interesting preliminary results are the first step for study and isolate other genes involved in polyphenol pathway in Jatropha curcas.