Comparative Transcriptome Analysis of Two Chrysomycin-Producing Wild-Type and Mutant Strains of Streptomyces sp. 891.

Chrysomycin A (CA), a promising antibiotic agent, usually coexists with two analog chrysomycins B (CB) and C (CC) produced by several wild-type (WT) Streptomyces strains. With the aim to increase CA production, UV mutagenesis-based breeding had been employed on a marine-derived strain Streptomyces sp. 891 in our previous study and afforded an improved strain 891-B6 with enhanced CA yield. By comparative transcriptome analysis, significant differences in chrysomycin BGC-related gene expression between the WT strain 891 and the mutant strain 891-B6 were unveiled in the current study. Among 25 up-regulated genes in mutant 891-B6, chryA , chryB , chryC , chryF , chryG , chryK , chryP , and chryQ , responsible for the biosynthesis of benzonaphthopyranone aglycone, and chryD, chryE , and chryU in charge of production of its deoxyglycoside, were characterized. Furthermore, the expression of genes chryOII , chryOIII , and chryOIV responsible for the formation of 8-vinyl in CA from 8-ethyl in CB were greatly enhanced in strain 891-B6. These findings provide molecular mechanisms for increased yield of CA and decreased yield of CB for mutant 891-B6, which has potential application in industrial CA production.