Microbial Synthesis of Antibacterial Phenazine-1,6-dicarboxylic Acid and the Role of PhzG in <i>Pseudomonas chlororaphis</i> GP72AN

Abstract

<i>Pseudomonas chlororaphis</i> have been demonstrated to be environmentally friendly biocontrol strains, and most of them can produce phenazine compounds. Phenazine-1,6-dicarboxylic acid (PDC), with a potential antibacterial activity, is generally found in <i>Streptomyces</i> but not in <i>Pseudomonas</i>. The present study aimed to explore the feasibility of PDC synthesis and the function of PhzG in <i>Pseudomonas</i>. A PDC producer was constructed by replacing <i>phzG</i> in <i>P. chlororaphis</i> with <i>lphzG</i> from <i>Streptomyces lomondensis</i>. Through gene deletion, common start codon changing, gene silence, and in vitro assay, our result revealed that the yield of PDC in <i>P. chlororaphis</i> is associated with the relative expression of <i>phzG</i> to <i>phzA</i> and <i>phzB</i>. In addition, it is found that PDC can be spontaneously synthesized without PhzG. This study provides an efficient way for PDC production and promotes a better understanding of PhzG function in PDC biosynthesis. Moreover, this study gives an alternative opportunity for developing new antibacterial biopesticides.