title: Role of exopolysaccharide in salt stress resistance and cell motility of Mesorhizobium alhagi CCNWXJ12-2T.
abstract: Mesorhizobium alhagi, a legume-symbiont soil bacterium that forms nodules with the desert plant Alhagi sparsifolia, can produce large amounts of exopolysaccharide (EPS) using mannitol as carbon source. However, the role of EPS in M. alhagi CCNWXJ12-2T, an EPS-producing rhizobium with high salt resistance, remains uncharacterized. Here, we studied the role of EPS in M. alhagi CCNWXJ12-2Tusing EPS-deficient mutants constructed by transposon mutagenesis. The insertion sites of six EPS-deficient mutants were analyzed using single primer PCR, and two putative gene clusters were found to be involved in EPS synthesis. EPS was extracted and quantified, and EPS production in the EPS-deficient mutants was decreased by approximately 25 times compared with the wild-type strain. Phenotypic analysis revealed reduced salt resistance, antioxidant capacity, and cell motility of the mutants compared with the wild-type strain. In conclusion, our results indicate that EPS can influence cellular Na+content and antioxidant enzyme activity, as well as play an important role in the stress adaption and cell motility of M. alhagi CCNWXJ12-2T.
authors.affiliation: College of Life Sciences, State Key Laboratory of Crop Stress Biology in Arid Areas, Northwest Agriculture and Forestry University, Yangling, Shaanxi, 712100, China.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Liu
authors.affiliation: College of Life Sciences, State Key Laboratory of Crop Stress Biology in Arid Areas, Northwest Agriculture and Forestry University, Yangling, Shaanxi, 712100, China.
authors.forename: Yantao
authors.initials: Y
authors.lastname: Luo
authors.affiliation: College of Life Sciences, State Key Laboratory of Crop Stress Biology in Arid Areas, Northwest Agriculture and Forestry University, Yangling, Shaanxi, 712100, China.
authors.forename: Zhefei
authors.initials: Z
authors.lastname: Li
authors.affiliation: College of Life Sciences, State Key Laboratory of Crop Stress Biology in Arid Areas, Northwest Agriculture and Forestry University, Yangling, Shaanxi, 712100, China.
authors.forename: Jiamei
authors.initials: J
authors.lastname: Wang
authors.affiliation: College of Life Sciences, State Key Laboratory of Crop Stress Biology in Arid Areas, Northwest Agriculture and Forestry University, Yangling, Shaanxi, 712100, China. weigehong@nwsuaf.edu.cn.
authors.forename: Gehong
authors.initials: G
authors.lastname: Wei
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D001483:Base Sequence; D004251:DNA Transposable Elements; D007887:Fabaceae / Q000382:microbiology; D059128:Mesorhizobium / Q000187:drug effects* / Q000235:genetics / Q000502:physiology*; D009068:Movement / Q000187:drug effects; D005810:Multigene Family; D016296:Mutagenesis; D018517:Plant Roots / Q000382:microbiology; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism*; D012965:Sodium Chloride / Q000494:pharmacology*; D013312:Stress, Physiological / Q000187:drug effects* / Q000235:genetics; D013559:Symbiosis
chemical_list: D000975:Antioxidants; D004251:DNA Transposable Elements; D011135:Polysaccharides, Bacterial; D012965:Sodium Chloride
keywords: Antioxidant capacity; Cell motility; Exopolysaccharide; Mesorhizobium alhagi; Mini-Tn5