Phosphate enhances levan production in the endophytic bacterium Gluconacetobacter diazotrophicus Pal5.
Gluconacetobacter diazotrophicus is a gram-negative and endophytic nitrogen-fixing bacterium that has several beneficial effects in host plants; thus, utilization of this bacterium as a biofertilizer in agriculture may be possible. G. diazotrophicus synthesizes levan, a D-fructofuranosyl polymer with β-(2→6) linkages, as an exopolysaccharide and the synthesized levan improves the stress tolerance of the bacterium. In this study, we found that phosphate enhances levan production by G. diazotrophicus Pal5, a wild type strain that showed a stronger mucous phenotype on solid medium containing 28 mM phosphate than on solid medium containing 7 mM phosphate. A G. diazotrophicus Pal5 levansucrase disruptant showed only a weak mucous phenotype regardless of the phosphate concentration, indicating that the mucous phenotype observed on 28 mM phosphate medium was caused by levan. To our knowledge, this is the first report of the effect of a high concentration of phosphate on exopolysaccharide production.
Laboratory of Basic and Applied Molecular Biotechnology; Graduate School of Agriculture; Kyoto University; Kyoto, Japan.
Nao
N
Idogawa
Laboratory of Basic and Applied Molecular Biotechnology; Graduate School of Agriculture; Kyoto University; Kyoto, Japan.
Ryuta
R
Amamoto
Laboratory of Basic and Applied Molecular Biotechnology; Graduate School of Agriculture; Kyoto University; Kyoto, Japan.
Kousaku
K
Murata
Laboratory of Basic and Applied Molecular Biotechnology; Graduate School of Agriculture; Kyoto University; Kyoto, Japan.
Shigeyuki
S
Kawai
D000222:Adaptation, Physiological; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D060026:Endophytes / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D005630:Fructans / Q000096:biosynthesis*; D015870:Gene Expression; D041821:Gluconacetobacter / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D006602:Hexosyltransferases / Q000172:deficiency / Q000235:genetics*; D006861:Hydrogen Peroxide / Q000494:pharmacology; D018384:Oxidative Stress; D010641:Phenotype; D010710:Phosphates / Q000378:metabolism / Q000494:pharmacology*; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis
D001426:Bacterial Proteins; D005630:Fructans; D010710:Phosphates; D011135:Polysaccharides, Bacterial; C072599:levan; D006861:Hydrogen Peroxide; D006602:Hexosyltransferases; C021513:levansucrase
Gluconacetobacter diazotrophicus; ROS; exopolysaccharide; levan; sugarcane