SYNTHESIS OF EXTRACELLULAR POLYSACCHARIDE, EXTRACELLULAR ENZYMES, ANDXANTHOMONADIN IN XANTHOMONAS-CAMPESTRIS - EVIDENCE FOR THE INVOLVEMENT OF 2 INTERCELLULAR REGULATORY SIGNALS

In previous work, the pigB transcriptional unit of Xanthomonas campest ris was implicated in the generation of a diffusible factor (DF) that regulates xanthomonadin and extracellular polysaccharide (EPS) product ion. Similarly, the rpfF and rpfB genes were implicated in the generat ion of a diffusible factor (DSF) that regulates the production of extr acellular enzymes and EPS. In this study, extracellular cross-feeding studies with rpfF and pigB mutant strains provided evidence for the ex istence of two separate intercellular signaling systems with overlappi ng roles in the regulation of EPS production.