表观遗传的化学干预对金龟子绿僵菌次生代谢产物影响的研究

The effect of chemical intervention of epigenetics on secondary metabolites of Metarhizium anisopliae

摘要:

[背景] 表观遗传酶类化学抑制剂对真菌的影响研究主要集中在新次生代谢产物挖掘方面，而对大量已知次生代谢物含量的变化却关注较少。金龟子绿僵菌是一种常用杀虫真菌，能代谢出多种已知生物活性物质，其含量可能会影响到该菌与环境间关系及利用潜力。[目的] 评估组蛋白去乙酰化酶和DNA甲基转移酶的化学抑制剂对金龟子绿僵菌代谢物安全性和可利用性的影响。[方法] 在金龟子绿僵菌培养基中添加表观遗传酶类化学抑制剂，培养一定时间后用高分辨液质联用及标准品对照方法分析次生代谢产物变化。根据差异代谢物的生物活性评估化学抑制剂的影响。[结果] 高分辨液质联用分析结果表明当抑制剂浓度达500μmol/L时，金龟子绿僵菌有16种主要次生代谢产物出现明显量的变化，包括destruxin A、A1、A2、B、B1、B2、E、E2、Ed、didesmethyldestruxin C、dihydrodestruxin A、desmethyldestruxin B、12-hydroxyovalicin、subglutinol C、fungerin和ustilagic Acid C。其中，丁酸钠处理可使15种主要代谢物含量升高。苯甲酰胺可使12种主要代谢物含量升高。伏立诺他虽然仅能使10种主要代谢物含量升高，但部分代谢物的升高幅度明显高于前两者。2种DNA甲基转移酶抑制剂可使金龟子绿僵菌代谢物中绿僵菌素类代谢物含量普遍下降。[结论] 组蛋白去乙酰化酶抑制剂可引起金龟子绿僵菌主要代谢物含量普遍升高，而DNA甲基转移酶抑制剂使金龟子绿僵菌的绿僵菌素含量普遍下降。由于变化的代谢物都具有显著的杀虫、免疫抑制或抗菌抗癌等生物活性，因此上述化学抑制剂可增强或降低金龟子绿僵菌对环境中昆虫毒性，同时也增加或降低其代谢物利用潜力。另外，subglutinol C、fungerin和ustilagic Acid C是首次在金龟子绿僵菌中被发现。

关键词:金龟子绿僵菌;组蛋白去乙酰化酶抑制剂;DNA甲基转移酶抑制剂;次生代谢产物;高分辨液质联用

Abstract:

[Background] Studies about effects of epigenetic enzyme chemical inhibitors on metabolites of fungi mainly focus on new metabolites mining while content change of large number of known metabolites are less concerned. Metarhizium anisopliae is a common insecticidal fungus which can synthetize many known bioactive metabolites. Content variation of the metabolites can possibly affect the relationship between the fungus and the environment and its utilization potential.[Objective] To assess the effects of histone deacetylase and DNA methylase inhibitors on the safety and availability of metabolites of M. anisopliae. [Methods] Chemical inhibitors of epigenetic enzyme were added in medium of M. anisopliae. After a period of cultivation the metabolic changes were analyzed with high-performance liquid chromatography (HPLC) combined with high-resolution mass spectrometry (HRMS) and with some standards comparison. The effects of the inhibitors were evaluated by the bioactivities of the changed metabolites. [Results] Results of HPLC-HRMS showed that the content of 16 main metabolites of M. anisopliae changed significantly while the concentration of the inhibitors reached 500 μmol/L. The changed metabolites included destruxin A, A1, A2, B, B1, B2, E, E2, Ed, didesmethyldestruxin C, dihydrodestruxin A, desmethyldestruxin B, 12-hydroxyovalicin, subglutinol C, fungerin and ustilagic acid C. Sodium butyrate can increase 15 of the main metabolites production, and benzamide can increase 12 of the main metabolites production. Despite that SAHA can only increase 10 of the main metabolites production, some of the increased levels were much higher than the two formers. All the destruxins were decreased in the DNA methylase inhibitors treated M. anisopliae. [Conclusion] Chemical inhibitors of histone deacetylase can increase the contents of the main metabolites of M. anisopliae while inhibitors of DNA methylase can decrease all the destruxins in the fungus. Because of that all the main variated metabolites possess insecticidal, immunosuppressive, antibacterial, anti-cancer or other biological activities, the above inhibitors can strengthen or weaken the toxicity of the fungus against insects in the environment and increase or decrease metabolic utilization value of the fungus. Additionally, subglutinol C, fungerin and ustilagic acid C were identified for the first time from M. anisopliae.

Key words:Metarhizium anisopliae;histone deacetylase inhibitors;DNA methylase inhibitors;secondary metabolites;liquid chromatography combined with high-resolution mass spectrometry