Phenotypic alterations caused by spontaneous and transposon mutagenesis in Pseudomonas tolaasii

Among different kinds of edible mushrooms, white button mushroom is the most cultivated in the majority parts of the world. Pseudomonas tolaasii is the important causal agent of brown blotch bacterial disease of mushroom that reduces its marketing. To consider the fact that by applying mutations, open reading frame of genes will change and important virulence factors cannot be produced as before. The aim of this investigation was further study on the role of these factors and compare the characteristics of phenotypic and genotypic alterations in mutants with the wild type strain. In this research, one isolate with intense pathogenicity factors was selected and the genome of that was altered by the use of spontaneous and transposon (mini Tn5) mutagenesis procedure. Among virulence factors in this bacteria, the effect of mutations on the production of pyoverdine, tolaasin, white line inducing principle and the motility of isolates were studied. The results of this investigation suggest the direct correlation between the production of pyoverdine, Tolaasin and white line inducing principle with the bacterial pathogenesis. On the other hand, no logical correlation was found in motility of the mutants with their pathogenicity. Further studies to identify the genes that are related to this process, are carrying out.