Volume 17 Part 1 Article 49: Extracellular Enzyme Producing Abilities of Pseudomonas Isolates Pathogenic to Oyster Mushroom

Volume 17 Part 1 Article 49
Year 2008
Title: Extracellular Enzyme Producing Abilities of Pseudomonas Isolates Pathogenic to Oyster Mushroom
Authors: A. Nagy, E. Sajben, Z. Antal, L. Manczinger and C. Vágvölgyi

Abstract:

Oyster mushroom (Pleurotus ostreatus) is one of the most extensively cultivated mushrooms in the world, but significant loss of crop and quality arises from blotch diseases caused by different bacterial pathogens. The yellowing and the brown blotch diseases, caused by Pseudomonas tolaasii are well known. The bacterium produces tolaasin toxins, which disrupt the cellular membrane by forming pores, and which can be identified easily using tolaasin toxin gene specific primers. Moreover, the blotch diseases caused by Pseudomonas tolaasii, and fluorescent pseudomonads such as P. agarici, P. constantinii and P. gingeri, can cause various other symptoms. In this study, the Pseudomonas strains of an infected Pleurotus ostreatus farm in Hungary were investigated. Sixty strains, belonging either to the fluorescent or to the non-fluorescent groups, were isolated on Pseudomonas selective S-1 medium, from rotted Pleurotus fruiting bodies, pre-fermented wheat straw substrate and water samples derived from mushroom growing houses. As a result of the in vitro antagonism tests, 40 isolates had mushroom growth inhibitory character. The strains were taxonomically identified by ARDRA and rpoB–RFLP techniques. Extracellular enzyme producing abilities of the strains were investigated by classical and modern chromogenic and fluorogenic substrate-using methods. The enzymes ß-1,3- glucanase, chitinase, protease and lipase enzyme systems were examined. Strong correlations were found between the levels of proteases and chitinases and the pathogenicity of the strains.

Please login to download the PDF for this proceeding.