Serratia plymuthica strain IC1270 isolated from the rhizosphere, possessing antagonistic activity towards a wide range of plant-pathogenic fungi, is able to hydrolyze phytate. Phytase activity was found intracellularly, while no activity was detected in the culture liquid. Optimum activity was found at pH 4-5; it completely disappeared at pH > 7.0 and 2.5. Phytase production was practically absent in the exponential phase and reached a maximum in the late stationary phase. Mutations of genes grrA and grrS, encoding GacA/GacS-like 2-component global regulatory system, or in gene rpoS encoding the sigma factor RpoS subunit of RNA polymerase, led to a deficiency in phytase production. Introduction into mutants of the respective wild-type genes cloned into the wide-range plasmid pJFF224-NX under the control of the bacteriophage T4 gene 32 promoter complemented this deficiency. This is the first report implicating the GacA/GacS global regulators and RpoS factor in phytase production in bacteria.

• MeSH
• 6-Phytase chemistry   genetics   metabolism   MeSH
• Bacterial Proteins chemistry   genetics   metabolism   MeSH
• Plant Roots microbiology   MeSH
• Gene Expression Regulation, Enzymologic * MeSH
• Gene Expression Regulation, Bacterial * MeSH
• Serratia chemistry   enzymology   genetics   MeSH
• Sigma Factor genetics   metabolism   MeSH
• Enzyme Stability MeSH
• Vitis microbiology   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• 6-Phytase MeSH
• Bacterial Proteins MeSH
• GacA protein, Bacteria MeSH Browser
• Sigma Factor MeSH

Quorum-sensing control mediated by N-acylhomoserine lactone (AHL) signal molecules has been established as a key feature in the regulation of various metabolic traits in many bacteria. Approximately 300 strains representing 6 genera and 18 species of soil-borne and plant-associated Gram-negative bacteria isolated in various regions of the former USSR using two reporter systems were screened for AHL production. The production was observed in 17.5% of the screened bacterial strains. Positive response was detected in all of the 14 tested strains of Erwinia herbicola, in 41 of the 239 strains of Pseudomonas species; in all 5 strains of Xanthomonas ampelina, X. campestris pv. malvacearum, pv. translucens, pv. vesicatoria and in one strain of Pantoea stewartii. AHL assay of 41 strains of X. maltophilia (syn. Stenotrophomonas maltophilia) isolated from soils with Chromobacterium violaceum reporter has revealed no strains synthesizing these signal molecules; 26 strains analyzed with Agrobacterium tumefaciens reporter showed the same result.

• MeSH
• 4-Butyrolactone analogs & derivatives   biosynthesis   metabolism   MeSH
• Gram-Negative Bacteria growth & development   metabolism   MeSH
• Soil Microbiology * MeSH
• Plants microbiology   MeSH
• Signal Transduction physiology   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• 4-Butyrolactone MeSH
• homoserine lactone MeSH Browser