AUTHOR=Li Kai-Huai , Yu Yong-Hong , Dong Hui-Juan , Zhang Wen-Bin , Ma Jin-Cheng , Wang Hai-Hong 

TITLE=Biological Functions of ilvC in Branched-Chain Fatty Acid Synthesis and Diffusible Signal Factor Family Production in Xanthomonas campestris

JOURNAL=Frontiers in Microbiology

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2017.02486

DOI=10.3389/fmicb.2017.02486

ISSN=1664-302X

ABSTRACT=<p>In bacteria, the metabolism of branched-chain amino acids (BCAAs) is tightly associated with branched-chain fatty acids (BCFAs) synthetic pathways. Although previous studies have reported on BCFAs biosynthesis, more detailed associations between BCAAs metabolism and BCFAs biosynthesis remain to be addressed. In this study, we deleted the <italic>ilvC</italic> gene, which encodes ketol-acid reductoisomerase in the BCAAs synthetic pathway, from the <italic>Xanthomonas campestris</italic> pv. <italic>campestris</italic> (<italic>Xcc</italic>) genome. We characterized gene functions in BCFAs biosynthesis and production of the diffusible signal factor (DSF) family signals. Disruption of <italic>ilvC</italic> caused <italic>Xcc</italic> to become auxotrophic for valine and isoleucine, and lose the ability to synthesize BCFAs via carbohydrate metabolism. Furthermore, <italic>ilvC</italic> mutant reduced the ability to produce DSF-family signals, especially branched-chain DSF-family signals, which might be the main reason for <italic>Xcc</italic> reduction of pathogenesis toward host plants. In this report, we confirmed that BCFAs do not have major functions in acclimatizing <italic>Xcc</italic> cells to low temperatures.</p>