Journal Article

Different and new Nod factors produced by Rhizobium tropici CIAT899 following Na+ stress

Estévez Amador, Jana, Universidad de Sevilla. Departamento de Microbiología y Parasitología, Córdoba, F. F. de, Soria Díaz, María Eugenia, Morón, Belén, Sousa Martín, Carolina, Universidad de Sevilla. Departamento de Química orgánica, Manyani, Hamid, Megías, Manuel, Brussel, Anton Albertus Nicolaas van, Thomas-Oates, Jane E, Dardanelli, Marta Susana, Ministerio de Educación y Cultura (MEC). España, Gil Serrano, Antonio Miguel

2009

Overview

The root nodule bacterium Rhizobium tropici strain CIAT899 is highly stress resistant. It grows under acid conditions, in large amounts of salt, and at high osmotic pressure. An earlier study reported a substantial qualitative and quantitative effect of acid stress on the biosynthesis of Nod factors. The aim of the present work was to investigate the effect of high salt (NaCl) concentrations, another common stress factor, on Nod factor production. For this purpose, thin-layer chromatography, HPLC and MS analyses were carried out. The expression of nodulation genes was also studied using a nodPlacZ fusion. High concentrations of sodium enhanced nod gene expression and Nod factor biosynthesis. The effect is sodium specific because high potassium or chloride concentrations did not have this effect. Under salt stress conditions, 46 different Nod factors were identified in a CIAT899 culture, compared with 29 different Nod factors under control conditions. Only 15 Nod factor structures were common to both conditions. Under salt stress conditions, 14 different new Nod factor structures were identified that were not observed as being produced under neutral or acid conditions. The implications of our results are that stress has a great influence on Nod factor biosynthesis and that new, very interesting regulatory mechanisms, worth investigating, are involved in controlling Nod factor biosynthesis

• Publisher: Oxford University Press,Oxford, UK : Blackwell Publishing Ltd,Blackwell Publishing Ltd,Wiley-Blackwell
• Subject: Abiotic stress / Acid resistance / Anti-Bacterial Agents - pharmacology / Artificial Gene Fusion / bacteria / Bacteriology / beta-Galactosidase - genetics / beta-Galactosidase - metabolism / Biological and medical sciences / Biosynthesis / Chromatography, High Pressure Liquid / Chromatography, Thin Layer / Fundamental and applied biological sciences. Psychology / Gene expression / Gene Expression Profiling / genes / Genes, Reporter / Genetics / High-performance liquid chromatography / Lipopolysaccharides - biosynthesis / Liquid chromatography / Mass Spectrometry / Microbiology / Nod factors / nod gene expression / Nod protein / Nodulation / Osmosis / Osmotic Pressure / Phaseolus / potassium chloride / Regulatory mechanisms (biology) / Rhizobium / Rhizobium tropici / Rhizobium tropici - chemistry / Rhizobium tropici - drug effects / Rhizobium tropici - metabolism / root nodules / salt stress / Salts / Sodium / Sodium chloride / Sodium Chloride - pharmacology / Stress, Physiological / Thin layer chromatography