大兴安岭林下凋落物慢速生长产孢真菌的隐秘代谢物及其抗菌活性

There are broad and flourish forests in Daxinganling region, of which the biodiversity is special and rich. The forests in Daxinganling region have lots of unexplored fungal resources. The fungal secondary metabolites are really rich and they are important sources of antimicrobial medicines. Recently, it was reported that fungal metabolites were cryptic because of the regulation of epigenetic and other factors and they could not be discovered by conventional methods. Therefore, the activation of the cryptic metabolites is a hot issue in the research area of fungal secondary metabolism. Based on the previous research, the applicant set up a series of unique and efficient methods for the slowly growing and sporulating fungi that is a neglected source. It laid a foundation for the research on the antimicrobial and cryptic metabolites from this kind of fungi. The slowly growing and sporulating fungi from forest litters in Daxinganling region will be selected as the investigated fungi. By the means involving genomics, molecular biology and fungal chemistry, the novel antimicrobial compounds will be searched from their cryptic metabolites. It is to explore the potential of the secondary metabolism of the slowly growing and sporulating fungi and it is also to synthesize novel antimicrobial compounds by fully use their biosynthetic gene clusters. This research would hopefully discover novel antimicrobial compounds and uncover their biosynthetic mechanisms. It also could provide the alternative lead compounds for new antibiotics and pesticides. Finally, it would provide the foundation for the utilization of the fungi from forests.

大兴安岭具有广茂的森林，生物多样性独特而丰富，林下有大量未被开发利用的真菌资源。真菌的次生代谢物十分丰富，是重要的抗菌药物来源。近期研究发现，真菌代谢物受表观遗传等因素影响，多处于“隐秘”状态，难以通过常规方法发现；所以隐秘代谢物的激活，成为了真菌次生代谢研究的热点。通过前期研究，申请人针对一类被忽视的真菌资源——慢速生长产孢真菌，建立起一系列独特、高效的方法，为该类真菌的抗菌隐秘代谢物的研究，打下了良好基础。本研究选择大兴安岭林下凋落物慢速生长产孢真菌作为研究对象，通过基因组学、分子生物学与真菌化学等手段，在其产生的隐秘代谢物中，寻找新型抗菌化合物。力求挖掘慢速生长产孢真菌的次生代谢潜力，充分利用其生物合成基因簇，合成新型抗菌化合物。通过本研究，可以发现新型抗菌化合物及其生物合成机理；为抗生素与农药的创制，提供备选先导化合物；为林下真菌资源的利用，提供研究基础。

大兴安岭具有广茂的森林与丰富森林凋落物。森林凋落物中包括枯枝、落叶、草本植物、小动物及其动物粪便等。森林凋落物的分解离不开真菌，森林凋落物也是真菌的良好栖息地。大兴安岭凋落物真菌中，包含大量未被培养、未被研究的真菌资源，具有被开发利用的潜力。本项目针对凋落物真菌，尤其是先前难以开发利用的慢速生长产孢真菌及其隐秘抗菌化合物，进行深入研究。在大兴安岭林下凋落物中共分离真菌800余株，其中700余株真菌进行了ITS初步鉴定；其中200余株真菌与数据库中已知真菌的ITS相似性为82.9%至98.5%，为具有较强新颖性的未培养或未描述真菌；此外利用相同方法，在长白山森林凋落物中分离培养了具有较强新颖性真菌58株。通过深入的形态学与分子生物学研究，建立真菌新属1个（黄微孢属）、建立兴安黄微孢菌、白色粘丝裸囊菌、长孢阿泽拉霉等新物种5个。通过筛选，发现多株具有抗菌活性及其他生物活性的慢速生长产孢真菌，对其中9株真菌的隐秘代谢物进行了追踪分离，对5株真菌的基因组进行了挖掘，对聚酮类、非核糖体肽类等隐秘代谢物的生物合成基因簇进行了分析，鉴定了28个单体化合物结构，其中6个为新结构化合物，如Phaeosphaeridiols A-C等。总结了营养矩阵结合发酵态法、表观遗传试剂法、表观遗传突变体法等方法的效果与规律；结合真菌的基因组与次生代谢物生物合成规律分析了抗菌隐秘代谢物的产生规律。通过以上研究，发表论文10余篇，申请发明专利6项。此外，还发现本项目中新建立的黄微孢属真菌还具有与植物根共生促进植物生长、抗逆等活性，具有较好的应用潜力，值得未来深入研究。