[Overexpression of LaeA enhances mevastatin production and reduces sporulation of Penicillium citrinum].

Objective: To study the regulation of laeA overexpression on mevastatin production and sporulation in Penicillium citrinum.

Methods: We cloned the laeA gene from Penicillium citrinum and constructed the vector pGiHTGi-laeA. The plasmid pGiHTGi-laeA was transformed in Penicillium citrinum by agrobacterium tumefaciens-mediated transformation. Positive transformants were detected by cloning the hygromycin gene. The mevastatin production of the wild type and OE:: laeA was compared by HPLC. The conidia number was counted by blood counting chamber. The biosynthetic gene cluster expression quantity of mevastatin in the wild type and OE: :laeA were analyzed by qRT-PCR.

Results: We constructed the plasmid pGiHTGi-laeA, and screened the positive transformants that overexpress the laeA in Penicillium citrinum. With the overexpression of laeA, the mevastatin production was increased from (0.69 ± 0.12) mg/g to (4.02 ± 0.50) mg/g dry cell weight. Compared to the wild type strain, the laeA expression quantity in the OE :: laeA strain increased 29%, and the mlcB expression increased 72%, the mlcR expression increased 153%. Moreover, the overexpression of laeA would decrease the conidia number.

Conclusion: Overexpression of LaeA enhances mevastatin production and reduces sporulation of Penicillium citrinum, with increases expression of pathway-regulator mlcR, and biosynthetic gene MlcR. These results could guide global regulatory mechanism of mevastatin biosynthesis and the exploitation of high-production strain.