| Background:As in recent years, epigenetic research in tumor cells growing in depth, many microbiologists gradually introduced to the discipline on the fungal secondary metabolite research. Epigenetics refers to DNA sequences in the chromosomes does not change, gene expression is heritable changes have taken place, and its molecular mechanisms including DNA methylation, histone modification, chromatin remodeling and RNA interference. In fungi, more research is about DNA methylation, histone methylation and acetylation. At present, By over-expressing or deleting the epigenetic modified genes and using small molecule epigenetic modifying agents to change fungal chromosome modified forms, we can improve production of microbic secondary metabolites and activate the silent biosynthesis gene clusters successfully. With the excessive use of antibiotics in recent years, resulting in a lot of drug-resistant, many common diseases can not be cured by existing drugs, so search for new compounds for drug development is imminent. using small molecules to manipulate the fungal epigenome provides a needed tool for rapidly accessing potential pools of cryptic fungal natural products in their native hosts.Second, this methodology can be readily implemented in most labs without extensive retooling, giving it a wide scope of utilization.Third, this approach will significantly lessen the cost and effort of acquiring the products of silent secondary metabolic pathways since fungi do not need to be pre-screened using a multitude of culture conditions.Aim:In this study, by two small-molecule epigenetic agents suberoylanilide hydroxamic acid and 5-azacytidine on Pleurotus mutilus-04 for strain improvement. Observed the changes of P.mutilus-04 colonies, mycelium morphology and its secondary metabolites by useing small-molecule epigenetic agents.Methods:This experiment determines the MIC of two kind of small-molecule epigenetic agents by using 96 well plate. P.mutilus-04 cultured for one day,added-on 2 time MIC of the epigenetic agents, and then fermentation for 7 days.We use the microscope to carry on the observation to its mycelial, use the highly effective liquid chromatography to carry on the analysis to its secondary metabolites, and use the preparation highly effective liquid chromatography to separate compound A and D. Finally it carries on the structure analysis using the nuclear magnetic resonance spectrometer and the mass analyzer to the compound.Result:P.mutilus-04 modified with SAHA,its mycelial,colony morphology had no change, the compound A never produced in this fungi was discovered in intra-cellular, the compound A was scanned by UV and mass spectrometry analysis. In its fermentation broth, compound D had been Purification, which is a structural analogue of SAHA. The anticancer activity of compound D was significantly lower than SAHA. The production of pleuromutilin is six times lower than negative control in SAHA experimental group. However,there is no major changes between 5-azacytidine experimental group and negative control. Although it had no signigicant effect in secongdary metabolites of P.mutilus-04 by 5-azacytidine,but 5-azacytidine on colony morphology of P.mutilus-04 have a more significant impact, the colony radius was larger and myceliums were sparse.Conclusion:The colony morphology, mycelium morphology and secondary metabolites of P.mutilus-04 have different effects by SAHA and 5-azacytidine.It proves that the method can making Strain improvement not only in Aspergillus and Penicillium, but also in basidiomycetes. So this method has broad application.
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