Submitted to: Journal of Plant Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/1/1995
Publication Date: N/A
Citation: N/A Interpretive Summary: On the average, 20% of the dry weight of soybeans is oil, an attribute of considerable economic importance. An enzyme from chloroplasts called acetyl CoA carboxylase, is the rate limiting step in oil biosynthesis. Chloroplast acetyl CoA carboxylase from legumes is composed of several different subunits. As part of a project to study this enzyme, with the idea of manipulating oil content by biotechnological means, we have isolated and characterized DNA encoding one of the subunits of chloroplast acetyl CoA carboxylase from soybeans. This clone will be helpful in studying the enzyme in soybeans, and perhaps for manipulating the flux of metabolites through this important biosynthetic pathway in seeds.
Technical Abstract: A 5.6 kb Xho1-Xho1 fragment derived from the soybean chloroplast chromosome was cloned. Nucleotide sequence of this fragment revealed that it contained the rps16, accD, psa1 and petA genes. The fragment also contained four other open reading frames, ORF 203, ORF 151, ORF 103 and ORF 220. This cluster is homologous one in the pea chromosome where the whole region is co-transcribed. When DNA from the cloned soybean gene cluster was used as a probe, high molecular weight soybean mRNA from seeds was detected by Northern blot hybridization experiments. The accD gene, which encodes beta-carboxytransferase from acetyl CoA carboxylase, from soybean is greater than 65% homologous to coding regions for the same enzyme from tobacco, beechdrop, dodder and pea. It has about 40% homology to the E. coli beta carboxylase subunit of acetyl CoA carboxylase.