Kocuria sp. a potential antagonist of Brown blotch caused by Pseudomonas tolaasii
By: Zeinab Namazi, Nader Hasanzadeh, Javad Razmi
Key Words: Biocontrol, Antagonist, Brown blotch, Pseudomonas tolaasii, Agaricus bisporus.
J. Bio. Env. Sci. 8(1), 159-166, January 2016.
Brown blotch disease, caused by Pseudomonas tolaasii, is a serious economic problem in the cultivation of the white button mushroom Agaricus bisporus in Iran. In this study, to screen antagonistic bacteria, 29 bacterial strains were isolated from wild mushrooms and 125 strains obtained from mushroom cultivation centers in Tehran province that were surveyed and samples were taken from button caps with or without visible symptoms, on the basis of their colony morphology. All isolates screened for biological control of Bacterial Blotch disease of cultivated mushroom caused by P. tolaasii in vitro. Among all tested bacteria, four isolates produced variable inhibition zones and reduced the symptom incidence on tissue blocks of A. bisporus. The polymerase chain reaction products of the bacterial strains were sequenced. Based on phenotypic, biochemical and molecular characteristics, the bacterial antagonists were identified as Pseudomonas spp. and Kocuria sp. The formation of blotches was entirely blocked by co-incubated antagonist and pathogen on mushroom sporocarps. To our knowledge, this is the first report of kocuria sp being a promising candidate as a biological control agent against P. tolaasii. Overall results of this study suggest that bacterial antagonists may be potential biocontrol agents for biological promotion of the health and growth of button mushroom.