核桃内生真菌SYS-5-2的鉴定及其抑菌活性

Identification and Antimicrobial Activity of Endophytic Fungus SYS-5-2 from Walnut

选取实验室保存的核桃内生真菌SYS-5-2,对其进行形态学和分子生物学鉴定,并通过生长速率法综合评价该菌株发酵产物的抑菌活性。结果表明,综合形态学分类方法和基于ITS序列基础上的系统发育分析,核桃内生真菌SYS-5-2鉴定为裂褶菌属。菌株SYS-5-2发酵产物对供试的6种植物病原菌均有不同程度的抑菌效果;液体发酵产物浓缩倍数越大,抑菌率越高,且相同浓度下,供试液B的抑菌效果整体优于供试液A;固体发酵产物中,乙酸乙酯和正丁醇相萃取物对水稻纹枯和苹果腐烂病原菌均表现出较好的抑菌效果,抑菌率均>90%;不同浓度的乙酸乙酯萃取物对6种病原菌的抑菌效果不同,浓度20 mg·mL^-1时,对水稻纹枯病原菌的抑菌率已达到81.25%,80 mg·mL^-1时,完全抑制了水稻纹枯病原菌的生长,IC 50仅为10.28 mg·mL^-1,而对其他病原菌的IC 50都在33.19~43.47 mg·mL^-1。

In this study,the endophytic fungus SYS-5-2 of walnut preserved in laboratory was identified by morphology and molecular biology,and the antimicrobial activity of the fermentation product of the strain was evaluated comprehensively by the growth rate method.The endophytic fungus SYS-5-2 was identified as Schizophyllum commune by morphological taxonomy and phylogenetic analysis based on ITS sequence.The fermentation products of the strain SYS-5-2 had different antimicrobial effects on six plant pathogens tested.The higher the concentration multiple of liquid fermentation products,the higher the inhibition rate.And at the same concentration,the antimicrobial effect of test solution B was better than that of test solution A.In the solid fermentation products,ethyl acetate and N-butanol phase extracts showed good antimicrobial effects on Thanatephorus cucumeris and Valsa ceratosperma,and the inhibition rates were above 90%.Different concentrations of ethyl acetate extracts had different antimicrobial effects on six pathogenic fungi,when the concentration was 20 mg·mL^-1,the inhibition rate against Thanatephorus cucumeris reached 81.25%,when the concentration was 80 mg·mL^-1,the growth of Thanatephorus cucumeris was completely inhibited.And the IC50 was only 10.28 mg·mL^-1,when the IC50 of other pathogens ranged from 33.19 mg·mL^-1 to 43.47 mg·mL^-1.