产几丁质酶内生放线菌的筛选及其对核盘菌的抑制作用

Screening of plant endophytic actinomycetes producing chitinase and its antagonistic activity against Sclerotinia sclerotiorum

采用透明圈法对分离自9种植物的186株高产几丁质酶内生放线菌进行筛选,获得1株分离自黄精块茎的菌株GKSHJA,用液培法测定其对病原菌的抑制效果.结果表明:该菌株对油菜菌核病菌的抑制率为85.4%,该菌的粗酶液对其他10种常见植物病原菌菌丝生长具有不同程度的抑制效果;依据形态学特征、生理生化特性和细胞化学分析,该菌株被鉴定为黄色长孢链霉菌(Streptomyces longisporoflavus);对GKSHJA菌株产酶条件的研究结果表明,当碳源为1%的粉状几丁质,氮源为0.30%的牛肉膏,初始pH6,32℃培养6d时,培养液中几丁质酶活性较高.

One hundred and eighty-six endophytic actinomycetes strains isolated from nine kinds of plants were screened for chitinase production by showing the transparent zone on the selective media containing chitin,and a high-yield strain GKSHJA of chitinase isolated from the stem of Polygonatum sibirium was obtained,whose antifungal activity on some common plant pathogens was evaluated by using liquid shake culture.The results showed that strain GKSHJA had high inhibition efficiency not only on Sclerotinia sclerotiorum with 85.4% inhibition rate to mycelial growth,but also on other 10 kinds of phytopathogens.The strain GKSHJA was identified as Streptomyces longisporoflavus based on morphological,physiological and biochemical,and cytochemical characteristics.The medium with initial pH 6,containing 1% floury chitin as carbon source and 0.30% beef extract as nitrogen source,incubated at 32 ℃ for 6 d with 150 r·min-1,was recommended for chitinase production of the strain GKSHJA.