2025 Volume 24 Issue 3 Pages 193-200
Pseudomonas tolaasii causes blown blotch and rotting in Pleurotus ostreatus. Previously, the Ps. tolaasii mutant MUR31 was generated by a single transposon (mini-Tn5km1) insertion into the regulatory gene rtpA+ of the wildtype PT814. MUR31 exhibits pleiotropic deficiency in pathogenicity-related traits, such as tolaasin production, the main cause of brown blotch. Transformation of MUR31 by recombinant rtpA+ DNA resulted in the wild-type trait restoration. However, in this study, we report that MUR31 carrying the rtpA+ DNA exhibits the same over-elongated cells on Pl. ostreatus as MUR31 carrying the vector plasmid. To the best of our knowledge, this is the first report of over-elongated cells of a Ps. tolaasii mutant defective in tolaasin production and associated with mushrooms that do not revert to wild-type morphology by the wild-type allele of the mutated gene. Whether epigenetics or other changes in the genome structure is responsible for the phenomenon needs to be clarified.
