Volume 16 Part 1 Article 56: Causal Agents of Bacterial Blotch on Cultivated Agaricus bisporus in Canada

Volume 16 Part 1 Article 56
Year 2004
Title: Causal Agents of Bacterial Blotch on Cultivated Agaricus bisporus in Canada
Authors: A.J. Castle, D. Sivanesan, C. Dobbin and D.L. Rinker

Abstract:

In an effort to identify the bacteria causing blotch disease on Agaricus bisporus in Canada, bacteria were isolated from symptomatic mushrooms that had been collected at thirteen farms located in six provinces, including examples with an unusual post-harvest spotting syndrome. All isolates were tested for pathogenicity by the mushroom rapid pitting test. Of 170 isolates, 30% were non-pathogenic, 39% produced yellow blotch, 23% brown blotch and 8% dark brown blotch. Eighty-three isolates were identified according to morphological and biochemical properties and proteinase K-resistant polypeptide profiles. The genetic identity of these isolates was determined by amplified fragment length polymorphic analysis. Type specimens of Pseudomonas tolaasii and P. ‘reactans’ were included for comparison. Two bacterial species, Serratia liquefaciens and Cedecea davisiae, and one isolate of P. putida were found to cause blotch on A. bisporus. The remaining pathogenic isolates were all variants of P. fluorescens, which included P. tolaasii. The results of neighbor-joining analysis showed that the Pseudomonas isolates fit into seven distinct groups. 

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