The Study On Several Two-Component Signal Transduction Systems In Streptomyces Hygroscopicus 5008

Two-component signal transduction systems(TCSs)exist in most prokaryote.And they are very important signal transduction ways for bacteria.TCSs regulate the metabolism of nutrient element,synthesis of enzymes,formation of spores,development and differentiation of cells and the synthesis of products in secondary metabolism.It's well known that TCS contains a histidine kinase and a response regulator.The HK receive signals from the environment,and transfer them to the RR,leading to a series of downstream activities.What's more,the TCSs are mostly very complex,and very different to be explained thoroughly.There are amounts of TCSs that need more research.Streptomyces is renowned for its complexity in metabolism,life cycle and morphological differentiation.And it is always an important field in biology.What's more,Streptomyces produces many kinds of antibiotics and exoenzymes,which makes it a valuable microbial group.So study on the regulation of its secondary metabolism and the way to increase the production of antibiotics and exoenzymes are very significant for application and making economic value.This research focuses on a subspecie of Streptomyces hygroscopicus var.Jinggangenisis 5008.The genome of Streptomyces hygroscopicus 5008 was completely sequenced and identified.By analysis of these genomic results,we know more about the biosynthesis process of validamycin.Sequence analysis shows that Streptomyces hygroscopicus 5008 contains 53 pairs of TCSs and 28 unpaired TCS.This research studyed several groups of TCSs about their regulation mechanism.In this research,we firstly amplified the targeted gene,constructed the recombined shuttle plasmids and got the mutants through conjugation between Streptomyces and E.Coli.Then,the phenotypic and antibiotic analysis on the mutants was conducted to screen the mutants with phenotypic variation.And we carried out transcriptomic and translational analysis to know more about the regulation mechanism of these TCSs.After a series of experiments,we finally got 5 mutants deleted targeted gene in our research:mutant ?SHJG1922,?SHJG4305/4306,?SHJG4527/4528,?SHJG4927/4928 and ASHJG6929.The phenotypic analysis showed that mutant?SHJG4527/4528 was different from wild strain in colonial morphology and spore formation condition.What's more,its ability to inhibit the corn southern leaf blight was much stronger than the wild strain.So we suggest that the TCSs SHJG4527/4528 might regulate the expression of some gene related with spore formation,spore color,colonial morphology and the synthesis of cyclothiazomycin.Besides,HPLC analysis revealed that the production of validamycin in mutant?SHJG6929 was much higher than wild strain,and we got the same result in RT-PCR analysis.We suggest that the orphan gene SHJG6929 might play a role in the regulation of the synthesis of validamycin.