Screening of antagonistic bacterium strain against Saprolegnia sp. and the preliminary study of the antagonistic substance
LEI Cui-xia, ZHANG Qi-zhong, XU De-lin
Institute of Hydrobiology, Jinan University, Engineering Research Center of Tropical and Subtropical Aquatic Ecological Engineering Ministry of Education, Key Laboratory of Aquatic Eutrophication and Control of Harmful Algal Blooms of Guangdong Higher Education Institutes, Guangzhou 510632, China
Saprolegniasis is a common disease of fresh water and brackish water fish. The pathogens are water molds, belonging to the genus Saprolegnia. In this study, six bacterial isolates from multiple fish farm ponds could inhibit the growth of the molds, which were named as SZK15, XL03, TG08, DJ12, HD05 and DS08, and the strain SZK15 showed the strongest anti-mold efficacy. In PDA media, the SZK15 presented an inhibition distance of 11.5 mm on the hyphae and an inhibition zone of 29.7 mm on the spores. The 10 times concentrated cell-free extract of the SZK15 fermentation culture gave an inhibition zone of 30.2 mm on the spores. In the broth assay, the undiluted cell-free culture supernatant of the SZK15 could completely inhibit the hyphal growth and spores germination. The hyphae were inhibited at the length of 2.0 mm and just 30% spores germinated in the 1/5 diluted supernatant. The hyphal growth from germinated spores was also inhibited, and could not form into hyphal nets. The antagonistic substance of SZK15 was sensitive for 121℃ high temperature, and was partly sensitive for 80℃, 100℃ high temperature, protease K and trypsinase. This study provides a potential new bio-control pathway for saprolegniasis in aquaculture in future.
雷翠霞, 张其中*, 许德麟. 水霉拮抗菌的筛选与拮抗物特点初步分析[J]. , 2013, 32(2): 189-193.
LEI Cui-xia, ZHANG Qi-zhong, XU De-lin. Screening of antagonistic bacterium strain against Saprolegnia sp. and the preliminary study of the antagonistic substance. , 2013, 32(2): 189-193.
