Expression of specmc proteins in oil biosynthesis and doning of genes encoding biotin carboxylase subunit of ht-ACCase and enoyl-ACP reductase from oil palm mesokarp (Elaeis guineensis Jaq).

Abstract

The availability of genes involved in palm oil biosynthesis and the understanding on regulation of their expression are important factors in genetic engineering to improve oil productivity and quality. As a preliminary research work on genetic engineering of palm oil metabolism, this research was aimed to identify and clone genes encoding key enzymes of oil biosynthesis in the mesocarp. Four research activity covering proteomic and genomic approaches, were conducted. These were (1) Detection, isolation and identification of proteins differentially expressed during fruit development; (2) Expression of ACCase and cloning of gene encoding biotin carboxylase subunit of ht-ACCase from oil palm mesoarrp; (3) Cloning of gene encoding enoyl-ACP reductase from oil palm mesocarp; and (4) Construction of eDNA library from oil palm mesocarp of 19 week after anthesis ~ AA) with 20 % oil content. The objective of the first research activities were to detect, isolate and identify proteins differentially expressed during fruit development and oil accumulation, in order to obtain infonnation on the enzymes that played important role in palm oil biosynthesis. Analysis of oil content and total protein in the mesocarp from different fruit development were conducted. The results showed that there was variation (from 17 to 21 WAA) on the time when the active period of oil synthesis started. Two protein bands with molecular weight of 31 and 34.3 kDa were differentially expressed during fruit development. Amino acid sequence of 31 kDa-protein was found to be homologous with biotin carboxytase subunit of ht-ACCase and enoyl·ACP reductase, while the 34.4 kDa-protein was homologous with glyceraldehydes-3P dehydrogenase. Based on results gathered from the first research adivities, oligonucleotide primers were designed and subsequently used in the second and third activities involving ampliftcation of the conserved region of genes encoding biotin carboxylase subunit of ht-ACase and enoyl-ACP reductase