Abundance of linear and circular plasmids among Streptomyces strains from Tibet plateau of China

Abstract:

[Objective] Investigation of occurrence of Streptomyces linear and circular plasmids in some extremely natural habitats. [Methods] Twenty soil samples from the Tibet plateau of China were collected, Streptomyces strains were identified and plasmids were isolated. [Results] Forty-six Streptomyces strains were obtained and, surprisingly, half of them harbored from one to four linear plasmids of 19–650 kb, and eight strains contained from one to four circular plasmids of 4–80 kb. [Conclusion] The abundance and diversity of linear and circular plasmids in Streptomyces strains from Tibet suggests that the extreme environmental stress, such as highly solar radiation, might induce DNA damage and repair to promote formation of varied plasmids.

Key words:Streptomyces, linear plasmid, circular plasmid