Cloning and expression of a plastid-encoded subunit, beta-carboxyltransferase gene ( accD) and a nuclear-encoded subunit, biotin carboxylase of acetyl-CoA carboxylase from oil palm ( Elaeis guineensis Jacq.)

Abstract

Palm oil is the second largest traded oil or fat in the world market and palm is the most important crop grown mainly for its oil. Identified varieties of Elaeis guineensis Jacq., with a high oil content and produced through a selective breeding program, are desirable for improving the yield of oil, subsequently enhancing the economic feasibility of using oil palm in various applications, including bio-diesel. We have cloned the gene of biotin carboxylase ( accD) from E. guineensis Jacq. This gene encodes a plastid-coded subunit of heteromeric acetyl-CoA carboxylase (ACCase). The cDNA of accD gene (accession number DQ004687) has an open reading frame of 1479 bp that encodes a putative protein of 492 amino acid residues ( AAY86362) with a predicted molecular mass of 55.47 kDa. The heteromeric form of ACCase is important as it catalyzes the first committed step of fatty acid synthesis. There is evidence that collectively suggests that the expression of accD in plastids is crucial to the levels of heteromeric ACCase and in turn, to the amount of seed oil in plant. Here we support the hypothesis that the expression level of accD is correlated with the oil palm production by using a semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) and quantitative real-time polymerase chain reaction (real-time PCR) analysis. Moreover, we observed the similar expression profile in nuclear-encoded subunit, biotin carboxylase ( accC). This finding represents the genetic background of the expressed genes that correlate to high yield in plant and that ACCase can be used as a marker in the breeding program.