Conservation of the pyrrolnitrin biosynthetic gene cluster among six pyrrolnitrin-producing strains

The punABCD gene cluster from Pseudomonas fluorescens encodes the biosynthetic pathway for pyrrolnitrin, a secondary metabolite derived from tryptophan which has strong anti-fungal activity. We used the pun genes from P. fluorescens strain BL915 as a probe to clone and sequence homologous genes from three other Pseudomonas strains, Burkholderia cepacia and Myxococcus fulvus. With the exception of the prnA gene from M. fulvus, the deduced amino acid sequences were > 59% similar among the strains, indicating that the biochemical pathway for pyrrolnitrin biosynthesis is highly conserved. The prnA gene from M. fulvus is about 45% similar to prnA from the other strains and contains regions which are highly conserved among all six strains. (C) 1999 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.