EXPRESSION OF THE PHENAZINE OPERON IN PSEUDOMONAS CHLORORAPHIS SUBSP. AURANTIACA B-162 STRAINS CAPABLE OF 
 OVERPRODUCTION OF PHENAZINE COMPOUNDS

Abstract

For the bacterium Pseudomonas chlororaphis subsp. aurantiaca B-162 (wild type) and two mutant strains B-162/255 and B-162/17 capable of overproduction of phenazines, a quantitative evaluation of the phz-operon gene expression was carried out during the cultivation of bacteria on full (PMA) and minimal (M9) nutrient media in different phases of culture growth. It was shown that for P. chlororaphis subsp. aurantiaca, the most optimal reference genes are the genes encoding pyrroline-5-carboxylate reductase (p5cr) and the DNA gyrase subunit A (gyrA). An inverse relationship between the expression levels of phzA and phzB genes was registered for B-162/255 and B-162/17 strains. The expression pattern of the phzC and phzD genes of the B-162/17 strain cultivated on the M9 medium differs markedly from that
 in the other studied strains grown on both nutrient media. For all the studied strains, a clear relationship between the phzE gene expression and the nutrient medium was established. PCR-products of phzF and phzG genes in the strain B-162/255 were registered from 12 to 18 hours of cultivation, and in the strain B-162/17 they were registered on the 4th-6th day of cultivation, while in the B-162 strain the expression of these genes was not observed at the studied time points.