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Characterization of a Regulator pgsR on Endogenous Plasmid p2Sip and Its Complementation for Poly(γ-glutamic acid) Accumulation in Bacillus amyloliquefaciens
journal contribution
posted on 2019-03-14, 00:00 authored by Yibin Qiu, Yifan Zhu, Yatao Zhang, Yuanyuan Sha, Zongqi Xu, Sha Li, Xiaohai Feng, Hong XuBacillus amyloliquefaciens NX-2S154 is a promising
poly(γ-glutamic acid) (γ-PGA) producing strain discovered
in previous studies. However, the wild-type strain contains an unknown
endogenous plasmid, p2Sip, which causes low transformation efficiency
and instability of exogenous plasmids. In our study, p2Sip is 5622
bp with 41% G+C content and contains four putative open reading frames
(ORFs), including genes repB, hsp, and mobB and γ-PGA-synthesis regulator, pgsR. Elimination of p2Sip from strain NX-2S154 delayed
γ-PGA secretion and decreased production of γ-PGA by 18.1%.
Integration of a pgsR expression element into the
genomic BamHI locus using marker-free manipulation
based on pheS* increased the γ-PGA titer by
8%. pgsR overexpression upregulated the expression
of γ-PGA synthase pgsB, regulator degQ, and glutamic acid synthase gltA, thus increasing
the γ-PGA production in B. amyloliquefaciens NB. Our results indicated that pgsR from p2Sip
plays an important regulatory role in γ-PGA synthesis in B. amyloliquefaciens.