Functions of genes encoding phosphomevalonate kinase and mevalonate diphosphate decarboxylase in Cordyceps militaris

Abstract:

[Objective] To determine the functions of two key enzymes of the mevalonate pathway, phosphomevalonate kinase (CmErg8) and mevalonate diphosphate decarboxylase (CmErg19), in Cordyceps militaris and their effects on the content of ergosterol and cordycepin. [Methods] Bioinformatics analysis was conducted to identify CmErg8 and CmErg19 in C. militaris, and yeast complementation was employed to determine whether their functions were conserved. Furthermore, we employed Agrobacterium tumefaciens-mediated transformation to overexpress CmErg8 and CmErg19 in the auxotrophic mutant CmΔpyrG of C. militaris, so as to observe the effects of CmErg8 and CmErg19 on the content of ergosterol and cordycepin. [Results] CmErg8 and CmErg19 could not complement the temperature sensitivity of the erg8 and erg19 mutants of yeast. The strains overexpressing CmErg8 and CmErg19 showed increased content of ergosterol and cordycepin. Particularly, the cordycepin content increased by about 5 times in the strain overexpressing CmErg19 compared with that in the control. [Conclusion] This study revealed the functions of CmErg8 and CmErg19 in C. militaris and reported that the genes in the ergosterol synthesis pathway of C. militaris affected the content of cordycepin for the first time.