title: Elimination of indigenous linear plasmids in Streptomyces hygroscopicus var. jinggangensis and Streptomyces sp. FR008 to increase validamycin A and candicidin productivities.
abstract: Giant linear plasmids, which replicate independently of the chromosomes, widely exist in actinobacteria. Previous studies mostly focused on the replication and evolution of the linear plasmids or the secondary metabolite gene clusters and the resistance gene clusters therein. However, the relationships of the linear plasmids to the productivities of secondary metabolites have not been studied. In this work, we developed a method to eliminate the indigenous linear plasmid pSHJG1 in Streptomyces hygroscopicus var. jinggangensis, and validamycin A titer increased by 12.5% (from 19.16 ± 1.93 to 21.56 ± 2.25 g/L) in the high-yielding strain TL01 and 43.7% (from 4.67 ± 0.05 to 6.71 ± 0.21 g/L) in the wild-type strain 5008, whereas the cellular growth of the plasmid-cured mutant was reduced. Subsequently, the plasmid-cured mutant was complemented with three structure genes involved in cellular growth in pSHJG1 under the control of a strong PvalA promoter. Among them, the complementation of genes pSHJG1.069 and pSHJG1.072, encoding a putative hydrolase and putative P-loop ATPase, respectively, resulted in the restoration of cellular growth and validamycin A titer. Furthermore, the elimination of indigenous linear plasmid pHZ228 in the candicidin producer Streptomyces sp. FR008 also led to enhanced candicidin production and reduced cellular growth. Because of the wide distribution of indigenous linear plasmids in actinobacteria, the engineering strategy described here could be implemented in a variety of strains for the overproduction of various natural products.
authors.affiliation: School of Marine Sciences, Ningbo University, 818 Fenghua Road, Ningbo City, Zhejiang Province, 315211, People's Republic of China.|State Key Laboratory of Microbial Metabolism and School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, People's Republic of China.|Joint International Research Laboratory of Metabolic and Developmental Sciences, Shanghai Jiao Tong University, Shanghai, 200240, People's Republic of China.
authors.forename: Chenyang
authors.initials: C
authors.lastname: Lu
authors.affiliation: Institute of Health Sciences, School of Life Sciences, Anhui University, Hefei City, Anhui Province, 230039, People's Republic of China.
authors.forename: Hang
authors.initials: H
authors.lastname: Wu
authors.affiliation: School of Marine Sciences, Ningbo University, 818 Fenghua Road, Ningbo City, Zhejiang Province, 315211, People's Republic of China. suxiurong@nbu.edu.cn.
authors.forename: Xiurong
authors.initials: X
authors.lastname: Su
authors.affiliation: State Key Laboratory of Microbial Metabolism and School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, People's Republic of China. bailq@sjtu.edu.cn.|Joint International Research Laboratory of Metabolic and Developmental Sciences, Shanghai Jiao Tong University, Shanghai, 200240, People's Republic of China. bailq@sjtu.edu.cn.
authors.forename: Linquan
authors.initials: L
authors.lastname: Bai
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D002174:Candicidin / Q000096:biosynthesis*; D015964:Gene Expression Regulation, Bacterial; D005816:Genetic Complementation Test; D007294:Inositol / Q000031:analogs & derivatives* / Q000096:biosynthesis; D005810:Multigene Family; D009154:Mutation; D010957:Plasmids; D011401:Promoter Regions, Genetic; D064210:Secondary Metabolism / Q000235:genetics*; D013302:Streptomyces / Q000235:genetics* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D002174:Candicidin; C030790:validamycin A; D007294:Inositol
keywords: Elimination; Indigenous linear plasmid; Overproduction; Validamycin A