INDUCED PROTEIN PROFILE CHANGES IN ARSENATE TOLERANT AND SENSITIVE PSEUDOMONAS FLUORESCENS STRAINS
Pseudomonas fluorescens are gram‐negative, motile, rod‐shaped bacteria known for their metabolic versatility. Many strains of this species possess excellent capability to colonize plant roots, promoting plant growth in soils contaminated with toxic metals. P. fluorescens biotype F is a strain tolerant to arsenic which had been isolated previously from soil contaminated with arsenic and other toxic metals and characterized as a promoter of plant growth and accumulation of arsenic. In the present work we studied the protein profile of this strain together with the profile of a sensitive P. fluorescens CECT 378 in the presence and absence of sodium arsenate using two‐dimensional polyacrylamide gel electrophoresis (2D‐PAGE). The gels were analyzed by PDQuest, while the statistical significance was proved by ANOVA. We found 9 differentially expressed proteins in the tolerant strain ‐ 4 new proteins, 4 upregulated proteins and 1 downregulated proteins in the presence of 1000 ppm As. In the non‐tolerant strain there were 7 differentially expressed proteins ‐ 1 new protein, 3 upregulated proteins and 3 downregulated proteins. The identification of the proteins with MALDI‐TOF is in progress.