基因组DNA去甲基化法改良蛹虫草菌株高产虫草素及性状稳定性评价  

Enhanced Cordycepin Production of Cordyceps militaris by Genomic DNA Demethylation and the Evaluation of Its Stability

作　　者：朱巍巍[1,2] 李莉[2] 陈飞[2] 李杨[2] 王艳华[2] 包永明[1] 

机构地区：[1]大连理工大学生命科学与技术学院,大连116024 [2]辽宁省微生物科学研究院,朝阳122000

出　　处：《生物技术通报》2016年第12期47-52,共6页Biotechnology Bulletin

基　　金：辽宁省农业公关及产业化项目(2015209002);辽宁省农业领域重点培养青年人才项目(2014034)

摘　　要：基因组DNA去甲基化能够激活沉默基因,改变次级代谢产物谱,是一种全新的菌种改良途径。利用不同浓度的DNA甲基化酶抑制剂5-氮杂胞苷(5-aza C)处理蛹虫草菌株CM-L1,降低基因组DNA甲基化水平,高效液相色谱筛检得到改良株LB-C3和LD-A7,菌丝体中虫草素含量分别提升127%和144.3%。LD-A7不能形成子实体,推测与关键的DNA甲基化修饰作用被改变有关。经5次继代培养后,以虫草素含量为指标考察性状稳定性。随传代次数增加,基因组中甲基化的DNA含量增加,液体发酵菌丝体中的虫草素含量均显著降低,但是子实体中虫草素含量非常稳定,改良的菌株更适合栽培生产而非工业发酵。Genomic DNA demethylation may activate silenced gene,which alters secondary metabolite spectrum,and therefore it is acompletely novel approach for strain improvement. Using different concentrations of DNA methyltransferase inhibitor 5-azacytidine（5-aza C）totreat the Cordyceps militaris CM-L1,then the genomic DNA methylation level reduced. Further,the improved strains LB-C3 and LD-A7 wereacquired by screening with high performance liquid chromatography,and in which the contents of cordycepin in mycelium increased by 127%and 144.3% respectively. LD-A7 could not form a fruiting body,which was speculated to be related to the role of DNA methylation changed.The stability was investigated after 5 times subculture using the content of cordycepin as an indicator. With the subculture times increased,the methylated DNA in the genome increased,and the cordycepin in mycelium of liquid fermentation significantly decreased;however,the content of cordycepin in fruiting bodies was very stable,indicating that improved strains were better suited to the cultivation rather thanproduction in industrial fermentation.

关 键 词：DNA去甲基化 5-氮杂胞苷 蛹虫草 虫草素 

分 类 号：S567.35[农业科学—中草药栽培]