辣木内生真菌LM033的分离鉴定及其代谢产物抗植物病原菌活性

Isolation and identification of endophytic fungus LM033 obtained from Moringaoleifera Lam. and biological activity of the metabolites

目的:鉴定一株来自药用植物辣木根部的内生真菌菌株LM033,分离其抗植物病原菌活性代谢产物。方法:依据ITS序列测定结果对菌株LM033进行鉴定;采用硅胶柱层析,凝胶柱层析等色谱方法分离发酵液的乙酸乙酯提取物中的活性物质,并根据化合物的光谱分析(MS,1H-and13C-NMR,DEPT)确定化学结构。结果:菌株LM033被鉴定为链格孢属的一种,从该菌株分离得到5个化合物:链格苝醇(1),4,6,8(14),22-麦角甾四烯-3-酮(2),异细交链孢素(3),链格孢霉酚(4)和链格孢霉甲基醚(5)。5个化合物对被测试植物病原菌都有一定抑制活性,其中链格苝醇对供试的植物病原菌有较好的抑制活性,相应的对灰葡萄孢和终极腐霉的IC50值分别为25.6和29.5μg·mL-1。结论:从辣木根部分离到的内生真菌链格孢属可产生对植物病原菌具有中等抑制活性的链格苝醇,对植物病害防治具有一定的意义。

Objective：To identify the endophytic fungus strain LM033 isolated from the roots of medicinal plant Moringaoleifera Lam. and to isolate the metabolites with inhibitory activity against phytopathogens. Methods： The strain LM033 was identified by analyzing ITS sequence. The ethyl acetate extract of the culture broth was puri- fied by column chromatography. The structures of the compounds were determined on the basis of spectroscopic an- alyses （MS,1H- and 13C-NMR,and DEPT）. Results ：The fungus strain LM033 was identified as Alternariasp. Five compounds were obtained and their structures were determined as alterperylenol （ 1 ）, ergosta-4,6,8 （ 14 ）, 22-tet- raen-3-one （2）, ahenuisol （3）, alternariol （4）, and alternariolmethyl ether （ 5 ）. The five compounds showed certain inhibitory activity against phytopathogens. Among which,compound 1 showed good growth inhibition against Botry- tiscinerea and Pythiumultimum with IC50 values of 25.6 and 29.5 μg. mL-1, respectively. Conclusion ： The endo-phytic fungus Alternaria sp. isolated from the roots of the medicinal plant M. olelfera can produce aherperylenol which show moderate inhibitory activity against plant pathogens, which is meaningful to disease protection of plants.