蛹虫草聚酮合酶基因的多样性分析

The Diversity of Polyketide Synthase(PKS) Gene in Cordyceps militaris

以蛹虫草的菌丝体为材料,利用基因组挖掘的方式从蛹虫草基因组中获得其聚酮合酶(Polyketide synthase,PKS)基因,对这些PKS基因进行生物信息学分析以推断它们的功能,并检测它们在不同培养基上的表达情况。结果表明:蛹虫草中含有13个PKS基因(CmPKS 1-13),包括2个非还原型聚酮合酶(Non-reducing PKS,NR-PKS),5个部分还原的聚酮合酶(Partial-reducing PKS,PR-PKS),6个高度还原型聚酮合酶(Highly reducing PKS,HR-PKS);聚类分析显示CmPKS 1、CmPKS 3可能参与链格孢吡喃酮(alternapyrone),CmPKS 4可能参与黄曲霉素,CmPKS 5可能参与美伐他汀,CmPKS 6可能参与分生孢子色素,CmPKS 8可能参与伊快霉素的生物合成,其余PKS与生物合成未知化合物的PKS聚为一支;半定量PCR显示CmPKS 7和CmPKS 9在4种培养基上均强烈表达;CmPKS 3、CmPKS 6在4种培养基上微弱表达;CmPKS 10、CmPKS 11和CmPKS 12只在GL培养基上强烈表达,在其余3种培养基上微弱表达;CmPKS 1和CmPKS 4只在GL培养上微弱表达,CmPKS 8仅在GS培养基上微弱表达;CmPKS 2、CmPKS 5和CmPKS 13在检测的培养基中都不表达。本研究为进一步异源表达蛹虫草中的PKS基因及其功能鉴定、具新颖结构聚酮化合物的发掘奠定基础。

The mycelium of Cordyceps militaris was used as the material,the present experiment has obtained some polyketide synthase(PKS) gene from the genome of C.militaris with the method of genome-mining,and carried a bioinformatics analysis of these PKS genes to perform their function,and detected these PKS gene expression in the different medium.The results showed that there were 13 PKS(CmPKS 1-13) genes in the genome of C.militaris,including 2 non-reducing PKS(NR-PKS),5 partial reducing PKS(PR-PKS),6 highly reducing PKS(HR-PKS);the phylogenetic analysis revealed CmPKS 1,CmPKS 3 could involve in the biosynthesis of alternapyrone, CmPKS 4 could involve sterigmatocystin, CmPKS 5 could involve mevastatin,CmPKS 6 could involve conidial yellow pigment, CmPKS 8 could involve equisetin,and other PKS in C.militaris that could involve some compounds were unkow;the semi-quantitative RT-PCR revealed CmPKS 7 and CmPKS 9 strongly expressed in 4 medium,CmPKS 3 and CmPKS 6 slightly expressed in all 4 medium, CmPKS 10;CmPKS 11 and CmPKS 12 only strongly expressed in GL,and slightly in other 3 medium;CmPKS 1,CmPKS 4 only expressed in GL,and CmPKS 8 only slightly expressed in GS;CmPKS 2,CmPKS 5 and CmPKS 13 not completely expressed in 4 medium.This study provides some important basis for heterologously expression of the PKS gene in C.militaris,the identification of gene function,and for finding a new putative structure of polyketide.