蛹虫草CmFbk2基因调控纤溶酶合成及分生孢子产生

Cordyceps militaris CmFbk2 Gene Regulates Fibrinolytic Enzyme Synthesis and Conidium Production

利用生物信息学技术对蛹虫草(Cordyceps militaris)的基因组数据进行挖掘,找到潜在的纤溶酶编码基因CmFbk2,该基因全长为1810 bp、编码531个氨基酸,序列分析显示该蛋白为典型的嗜热菌蛋白酶。利用基因敲除技术获得突变菌株,分别对野生型菌株、突变菌株和回补菌株的表型进行观察,结果表明:突变菌株的产孢量下降,孢子萌发率和菌丝生长速度不受影响;进一步的表型分析显示,突变菌株在米饭培养基上只生长菌丝,不能形成正常形态的子实体,其回补菌株可以产生正常形态子实体;检测野生型菌株和突变菌株菌丝体、发酵液中的纤溶酶活性,与野生型菌株相比,突变菌株中的纤溶酶活性明显下降,回补菌株中的纤溶酶活性减少50%。

A candidate fibrinolytic enzyme encoding gene CmFbk2 was mined from the genome of Cordyceps militaris.This gene was found to be 1810 bp encoding 531 amino acids.The protein product CmFbk2 was predicted to be a typical thermophilic protease by protein sequence analysis.Then a CmFbk2 knockout mutant was generated and observed for mycelial growth on rice medium,fruiting body development,conidium production and fibrinolytic enzyme activity in both mycelia and fermentation broth.Compared with the wild-type strain,the CmFbk2 knockout mutant produced fewer conidia,whereas its sporulation rate and mycelial growth rate remained the gene same.Regardless of unaffected mycelial growth,the CmFbk2 knockout mutant was not able to develop normal fruiting bodies in morphology.On the other hand,the CmFbk2 complementation strain restored normal fruiting bodies.Fibrinolytic enzyme activity in the CmFbk2 knockout mutant and the gene complementation strain were about 10%and 50%of that in the wild-type strain,respectively.