Similarly, to amplify the Y27 oriC, two primers (5′-ATGCACGCCGACCGCAAGATC-3′, 5′-AYRSGTTGCCGAACAGTGGACA-3′) were used for the first round, and nested primers (5′-CCACGGCCCCGAATCCGCCTC-3′, 5′- GCACAACACCGGCCTGCCTGTG-3′) for the second round of the PCR reactions. To amplify the A3(2) oriC, primers used in the first round reaction were the same as in the Y27 oriC, and new nested primers (5′-GCCTTTCCCATGCCCCT.GGGT-3′, 5′-CCTGCCCTGATGATCCCTCACCAG −3′) for the second round of the PCR reactions. Acknowledgements We are very grateful to Sir David Hopwood for critical reading of and useful suggestions on the manuscript. This work was supported by grants from National “973” project (2011CBA00801),
Electronic supplementary material Additional file 1: Figure S1. Identification of fourteen indigenous plasmids. Fourteen plasmids from endophytic Streptomyces strains were digested with NcoI and electrophoresed in 1% agarose gel at 6.7 V/cm for 4 h. Sizes of five bands are indicated. (JPEG 32 KB) Additional file 2: Figure S2. Features of the 1136-bp sequence of the Y27 chromosomal oriC between the dnaA and dnaN genes. Taking the conserved DnaA binding-boxes of 9 bp (TTGTCCACA) in the S. lividans oriC as a reference , 25 DnaA binding-boxes of 9 bp (forward indicated by arrowheads and reverse by dashed arrowheads) for the Y27 oriC are predicted by the Vector NTI® 9.0 software (Invitrogen). Two AT-rich sequences are boxed. (JPEG 32 KB) Additional file 3: Figure S3. Identification of fourteen endophytic Streptomyces GPX6 strains. The plug-embedded mycelium of fourteen endophytic Streptomyces strains was digested with SspI and electrophoresed in a 1.0% pulsed-field gel at 8.6 V/cm, 10 s to 60 s switch time and 14oC for 22 h. (JPEG
32 KB) Additional file 4: Figure S4. Schematic map of pWTY27. Predicted ORFs and their transcription directions are indicated by arrowheads. The replication (repA and repB), transfer (traA) and other genes (int: integrase; phc: phage capsid; kor: kill-override; spd: spread) and site (iteron) are shown. (JPEG 32 kb) (JPEG 32 KB) Additional file 5: Table S1. Predicted ORFs of plasmid pWTY27. Detailed information and possible functions of the fifteen ORFs of pWTY27. (JPEG 32 KB) References 1. Goodfellow M, Williams ST: Ecology of actinomycetes. Ann Rev Microbiol 1983, 37:189–216.CrossRef 2. Xu LH, Tian YQ, Zhang YF, Zhao LX, Jiang CL: Streptomyces thermogriseus, a new species of the genus Streptomyces from soil, lake and hot-spring. Int J Syst Bacteriol 1998, 48:1089–1093.PubMedCrossRef 3. Hopwood DA: Soil to genomics: the Streptomyces chromosome. Annu Rev Genet 2006, 40:1–23.PubMedCrossRef 4. Bérdy J: Bioactive microbial metabolites.