Identification and biological control of Bacillus safensis HC42 against browning disease pathogen(Pseudomonas agarici) of button mushroom
Mushroom is cultivated as one of the major economical crops in many areas in Korea. The total production has steadily increased from approximately 186,400 M/T in 2007 to 190,111 M/T in 2011. The button mushroom, Agaricus bisporus, showed the 5th production to 13,052 M/T in 2011. Several bacteria are known as the causal agents of diseases of the cultivated button mushroom (Agaricus bisporus) and oyster mushroom (Pleurotus ostreatus). Pseudomonas agarici is the causal agent of browning disease of commercial mushrooms. Colonization of mushroom caps by the bacterium results in development of browning lesions on pileus. These lesions are superficial brown spots and can be round or spreading. But P. agarici never caused sunken lesions and rotting of the mushroom tissues. Antagonists against P. tolaasii, HC42 were selected and their control efficacy of browning disease was investigated in this study. Antagonists against P. agarici, HC42 were selected and their control efficacy of browning disease was investigated in this study. After proceeding antagonistic test, HC42 was selected as a strong antagonist against P. agarici and the HC42 strain was identified as P. safensis with the cultural, physiological and biochemical properties and analysis of the 16S rRNA. The optimal culture medium for the antagonistic bacteria growth was determined as follows: 1.5% D-galactose, 1.5% yest extract, 1% NH4Cl, 1.5% KCl, and 1.0% L-asparagin at pH 6.0 at 25℃. Control efficacy of browning disease by HC42 treatment was 66% on Agaricus bisporus..