Glycogen phosphorylase is involved in stress endurance and biofilm formation inAzospirillum brasilense Sp7

Abstract

Here we report the identification of a glycogen phosphorylase (glgP) gene in the plant growth-promoting rhizobacterium Azospirillum brasilense, Sp7, and the characterization of a glgP marker exchange mutant of this strain. The glgP mutant showed a twofold reduction of glycogen phosphorylase activity and an increased glycogen accumulation as compared with wild-type Sp7, indicating that the identified gene indeed encodes a protein with glycogen phosphorylase activity. Interestingly, the glgP mutant had higher survival rates than the wild type after exposure to starvation, desiccation and osmotic pressure. The mutant was shown to be compromised in its biofilm formation ability. Analysis of the exopolysaccharide sugar composition of the glgP mutant revealed a decrease in the amount of glucose, accompanied by increases in rhamnose, fucose and ribose, as compared with the Sp7 exopolysaccharide. To the best of our knowledge, this is the first study that demonstrates GlgP activity in A. brasilense, and shows that glycogen accumulation may play an important role in the stress endurance of this bacterium.

Reduction of hexavalent cromium by Serratia marcecens immobilized on active carbon and their potencial use in bioremediation

“…The polymeric matrix observed appears similar to that previously described in other microorganisms (Kobayashi 2007;Lerner et al 2009). These polysaccharides suffer different colloidal interactions, linking bacteria to the surface by a combination of weak chemical bonds, dipole interactions, and hydrophobic interactions (Hall-Stoodley et al 2004).…”

Arsenite Oxidation by Pseudomonas arsenicoxydans Immobilized on Zeolite and Its Potential Biotechnological Application

“…3c, g, bacterial cells are embedded by a matrix probably constituted by extracellular polysaccharides. The polymeric matrix observed appears similar to that previously described for other microorganisms (Lerner et al 2009). …”

A LysR-Type Transcriptional Regulator LcrX Is Involved in Virulence, Biofilm Formation, Swimming Motility, Siderophore Secretion, and Growth in Sugar Sources in Xanthomonas axonopodis Pv. glycines

“…For example, GlpG is a glycogen phosphorylase involved in glycogen metabolism. An Azospirillum brasilense strain deficient in GlpG had a different monosaccharide composition in extracted EPS and significantly reduced biofilm formation ability compared to the wild-type strain (Lerner et al, 2009). This study demonstrates that glycogen regulation is involved in biofilm formation and sugar metabolic pathways.…”