title: Only one of the five Ralstonia solanacearum long-chain 3-ketoacyl-acyl carrier protein synthase homologues functions in fatty acid synthesis.
abstract: Ralstonia solanacearum, a major phytopathogenic bacterium, causes a bacterial wilt disease in diverse plants. Although fatty acid analyses of total membranes of R. solanacearum showed that they contain primarily palmitic (C(16:0)), palmitoleic (C(16:1)) and cis-vaccenic (C(18:1)) acids, little is known regarding R. solanacearum fatty acid synthesis. The R. solanacearum GMI1000 genome is unusual in that it contains four genes (fabF1, fabF2, fabF3, and fabF4) annotated as encoding 3-ketoacyl-acyl carrier protein synthase II homologues and one gene (fabB) annotated as encoding 3-ketoacyl-acyl carrier protein synthase I. We have analyzed this puzzling apparent redundancy and found that only one of these genes, fabF1, encoded a long-chain 3-ketoacyl-acyl carrier protein synthase, whereas the other homologues did not play roles in R. solanacearum fatty acid synthesis. Mutant strains lacking fabF1 are nonviable, and thus, FabF1 is essential for R. solanacearum fatty acid biosynthesis. Moreover, R. solanacearum FabF1 has the activities of both 3-ketoacyl-acyl carrier protein synthase II and 3-ketoacyl-acyl carrier protein synthase I.
authors.affiliation: College of Life Sciences, South China Agricultural University, Guangzhou, China.
authors.forename: Juanli
authors.initials: J
authors.lastname: Cheng
authors.forename: Jincheng
authors.initials: J
authors.lastname: Ma
authors.forename: Jinshui
authors.initials: J
authors.lastname: Lin
authors.forename: Zhen-Chuan
authors.initials: ZC
authors.lastname: Fan
authors.forename: John E
authors.initials: JE
authors.lastname: Cronan
authors.forename: Haihong
authors.initials: H
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D053898:Biosynthetic Pathways / Q000235:genetics; D005227:Fatty Acids / Q000096:biosynthesis*; D017353:Gene Deletion; D005798:Genes, Bacterial; D020043:Genes, Essential; D050296:Microbial Viability; D043368:Ralstonia solanacearum / Q000201:enzymology* / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D017855:Transferases (Other Substituted Phosphate Groups) / Q000235:genetics / Q000378:metabolism*
chemical_list: D005227:Fatty Acids; D017855:Transferases (Other Substituted Phosphate Groups); C021364:holo-(acyl-carrier-protein) synthase