Identification of engineered strain WSJ-IA with high proportion and high production of isovalerylspiramycinⅠand its original parent strain Streptomyces spiramyceticus F21

Abstract:

[Objective] A Streptomyces spiramyceticus WSJ-IA strain (herein designated as an isomycin I producer) with high proportion and high production of isovalerylspiramycin Ⅰwas obtained by cloning and expression of acyB2 (Regulatory gene) and ist (Isovaleryltransferase gene) into an isovalerylspiramycin Ⅰproducting strain. Taxonomic studies were carried out to define the engineered isomycin I producer and its original parent strain Streptomyces spiramyceticus F21. [Methods] 16S rRNA gene sequencing and five housekeeping genes (atpD、gyrB、rpoB、recA and trpB) coding proteins sequencing combining the traditional taxonomic studies, such as morphological, cultural, physiological and biochemical characteristics were performed for both strains. [Results] The Streptomyces spiramyceticus WSJ-IA and Streptomyces spiramyceticus F21 share highly similar phenotypes and 16S rRNA gene sequences as well as in the phenogenetic analysis of the five housekeeping gene protein sequences. While their 16S rRNA gene sequences and the five housekeeping gene protein sequences phylogenetically were located in different clades comparing with all other strains so far described. And the closely related strains with each gene coding protein were also different,none of them was as spiramycin producer reported. [Conclusion] Our results suggested that Streptomyces spiramyceticus F21 was possible a new Streptomyces sp. of spiramycin producer.16S rRNA gene sequence and five housekeeping genes (atpD、gyrB 、rpoB、recA and trpB ) coding proteins sequences could be served as genetic markers in identifying the engineered strain’s stability in long term of the commercial production.