Characterization of stearoyl-ACP desaturase (SAD) gene from Jessenia bataua

Jessenia bataua subsp. bataua is a monocaulous, pinnate-leaved palm native to the humid tropics of South America. Jessenia fruits are ovoid-ellipsoid in outline. The fleshy, variously coloured (greenish, white lavender) mesocarp has a high oil content ca. 30% or more of dry weight. The fruits of this species are especially important to indigenous peoples and yield high quality oil. The oil would provide a superior appeal that is described as a New World olive oil because of the quality that is similar in taste and chemical composition to olive oil. We aim to isolate and characterize fatty acid biosynthetic genes from Jessenia that have distinct fatty acid composition for comparative studies with oil palm species in order to provide evidences on the mechanism of fatty acid biosynthesis. By using molecular approaches, we have isolated the full length cDNA of stearoyl-ACP desaturase (SAD) from mesocarp tissues of Jessenia bataua. The full length sequence information of SAD was initially obtained by Rapid Amplification of cDNA Ends (RACE). End-to-end PCR was then performed to amplify the ~1.6 kb full length clone from both cDNA and genomic DNA. Sequence analysis suggests that the cDNA contains both desaturase and ferritin domains. Blast search analysis of SAD from Jessenia showed approximately 85% homology to that of oil palm. Southern blot analysis revealed that SAD is a multiple-copy gene. Currently, work is being focused towards expression studies of SAD in E.coli and plant systems