title: Sinorhizobium meliloti Functionally Replaces 3-Oxoacyl-Acyl Carrier Protein Reductase (FabG) by Overexpressing NodG During Fatty Acid Synthesis.
abstract: In Sinorhizobium meliloti, the nodG gene is located in the nodFEG operon of the symbiotic plasmid. Although strong sequence similarity (53% amino acid identities) between S. meliloti NodG and Escherichia coli FabG was reported in 1992, it has not been determined whether S. meliloti NodG plays a role in fatty acid synthesis. We report that expression of S. meliloti NodG restores the growth of the E. coli fabG temperature-sensitive mutant CL104 under nonpermissive conditions. Using in vitro assays, we demonstrated that NodG is able to catalyze the reduction of the 3-oxoacyl-ACP intermediates in E. coli fatty acid synthetic reaction. Moreover, although deletion of the S. meliloti nodG gene does not cause any growth defects, upon overexpression of nodG from a plasmid, the S. meliloti fabG gene encoding the canonical 3-oxoacyl-ACP reductase (OAR) can be disrupted without any effects on growth or fatty acid composition. This indicates that S. meliloti nodG encodes an OAR and can play a role in fatty acid synthesis when expressed at sufficiently high levels. Thus, a bacterium can simultaneously possess two or more OARs that can play a role in fatty acid synthesis. Our data also showed that, although SmnodG increases alfalfa nodulation efficiency, it is not essential for alfalfa nodulation.
authors.affiliation: Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China.
authors.forename: Ya-Hui
authors.initials: YH
authors.lastname: Mao
authors.affiliation: Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Li
authors.affiliation: Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China.
authors.forename: Jin-Cheng
authors.initials: JC
authors.lastname: Ma
authors.affiliation: Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Hu
authors.affiliation: Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China.
authors.forename: Hai-Hong
authors.initials: HH
authors.lastname: Wang
mesh_terms: D064431:3-Oxoacyl-(Acyl-Carrier-Protein) Reductase / Q000235:genetics / Q000378:metabolism*; D000429:Alcohol Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D005227:Fatty Acids / Q000096:biosynthesis* / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D000455:Medicago sativa / Q000382:microbiology; D009154:Mutation; D053204:Root Nodules, Plant / Q000382:microbiology; D016962:Sinorhizobium meliloti / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D005227:Fatty Acids; C060531:NodG protein, Rhizobium meliloti; D000429:Alcohol Oxidoreductases; D064431:3-Oxoacyl-(Acyl-Carrier-Protein) Reductase