The Preliminary Exploration Of Secondary Metabolites Biosynthesis In Streptomyces Luteosporeus NRRL2401

Streptomyces luteosporeus NRRL 2401 can produce two antibiotics, thiolutin and indolmycin, which show good bioactivity while problematic in application. In order to explore the secondary metabolites biosynthetic information in Streptomyces luteosporeus NRRL 2401, we undertook research in this strain preliminarily.First of all, Streptomyces luteosporeus NRRL 2401 was fermented to ensure it could produce thiolutin and indolmycin. Then, an optimized, stable “fermentation-separation-detection” system was built for the subsequent experiments. Meanwhile, the genetic manipulation system was developed by using conjugal transfer vectors p SET152, p PM927 and p JTU1278 which were transferred from Escherichia coli ET12567/p UZ8002 to S. luteosporeus. Moreover, the genomic library of S. luteosporeus NRRL 2401 was constructed by the fosmid vector p CCl FOSTM, with E. coli EPl300TM-T1 R as the host strain. The library contained 2880 clones with an average ~35 kb inserted DNA fragment in each clone, indicating the 99.99% coverage of the genome in the library.Besides, the whole genome was sequenced twice by solexa and SMRT. With the results spliced, a 6.7 Mb genome sequence including two contigs was provided. After sequence alignments by the bioinformatics softwares, the functions of 6222 genes were predicted.Taken indolmycin as an example, both biosynthesis pathway prediction and the complete genome sequence analysis were used to find indolmycin biosynthesis gene cluster. Unfortunately, there were no positive results except for a mutant strain CXQ-1 with different HPLC peaks from the wild-type strain.Finally, more metabolic biosynthesis information was discovered in the complete genome sequence, such as hybrid NRPS-PKS, aminoglycoside, terpene, siderophore and lantibiotic, which lay the groundwork for future researches about discovering more metabolic biosynthesis gene clusters. Among them, a kirromycin-like gene cluster needed more researches. Besides, two mutant strains CXQ-2 and CXQ-1 with different HPLC peaks could also contribute to the gene cluster mining in Streptomyces luteosporeus NRRL 2401.