title: Complex quorum-sensing regulatory systems regulate bacterial growth and symbiotic nodulation in Mesorhizobium tianshanense.
abstract: LuxR/LuxI-type quorum-sensing systems have been shown to be important for symbiotic interactions between a number of rhizobium species and host legumes. In this study, we found that different isolates of Mesorhizobium tianshanense, a moderately-growing Rhizobium that forms nodules on a number of types of licorice plants, produces several different N-acyl homoserine lactone-like molecules. In M. tianshanense CCBAU060A, we performed a genetic screen and identified a network of regulatory components including a set of LuxI/LuxR-family regulators as well as a MarR-family regulator that is required for quorum-sensing regulation. Furthermore, compared with the wild-type strains, quorum-sensing deficient mutants showed a reduced growth rate and were defective in nodule formation on their host plant Glycyrrhiza uralensis. These data suggest that different M. tianshanense strains may use diverse quorum-sensing systems to regulate symbiotic process.
authors.affiliation: Department of Microbiology, MOA Key Lab of Microbiological Engineering of Agricultural Environment, Nanjing Agricultural University, Nanjing, China.
authors.forename: Huijuan
authors.initials: H
authors.lastname: Cao
authors.forename: Menghua
authors.initials: M
authors.lastname: Yang
authors.forename: Huiming
authors.initials: H
authors.lastname: Zheng
authors.forename: Jiang
authors.initials: J
authors.lastname: Zhang
authors.forename: Zengtao
authors.initials: Z
authors.lastname: Zhong
authors.forename: Jun
authors.initials: J
authors.lastname: Zhu
mesh_terms: D054742:Acyl-Butyrolactones / Q000378:metabolism; D020561:Alphaproteobacteria / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D029882:Glycyrrhiza uralensis / Q000382:microbiology; D005810:Multigene Family; D016254:Mutagenesis, Insertional; D053038:Quorum Sensing; D053204:Root Nodules, Plant / Q000382:microbiology*; D013559:Symbiosis
chemical_list: D054742:Acyl-Butyrolactones