Functions of the wblA gene in marine-derived Streptomyces sp. OUCMDZ-3434

Abstract:

[Background] Streptomyces sp. OUCMDZ-3434 was isolated from Enteromorpha prolifera collected from the Zhanqiao Beach, Qingdao, Shandong, and it produced wailupemycins with good α-glycosidase inhibitory activity, but at very low yield. [Objective] To develop the genetic system of marine-derived Streptomyces sp. OUCMDZ-3434 and investigate the role of wblA gene on wailupemycins production. [Methods] Escherichia coli-Streptomyces intergeneric conjugation manipulation was established for Streptomyces sp. OUCMDZ-3434 using pSET152. wblA gene was inactivated by using PCR-targeting strategy. After confirmation by PCR, the fermentation broths of the wild-type and mutant strains were analyzed by HPLC, and morphological differentiation was observed by using phase contrast microscope. [Results] The conjugation method for Streptomyces sp. OUCMDZ-3434 was established and the wblA gene inactivation mutant was constructed. The yield of wailupemycin G in the wblA inactivation mutant was increased by 3-fold compared to that of the wild-type strain. Additionally, the wblA gene mutant lost the ability of sporulation. [Conclusion] The wblA gene in Streptomyces sp. OUCMDZ-3434 negatively regulates the biosynthesis of wailupemycins and is involved in regulation of sporulation as well. These results laid the foundation for yield improvement of wailupemycins by genetic manipulation.

Key words:Streptomyces sp. OUCMDZ-3434, intergeneric conjugation, PCR-targeting, gene inactivation