阿维链霉菌中ECF-Sig25的调控通路OA北大核心CSTPCD

The linkage regulation of extracytoplasmic function(ECF)sigma factors and two-component system(TCS)play essential roles for bacteria adaptation to various environment and stress condition.In order to study the ECF-sig25 gene in Streptomyces avermitilis and explore the regulatory pathway of Sig25,the response of Sig25 to stress was detected by spore spot test,its influence on morphological differentiation was analyzed by plate culture,and the target gene of Sig25 was verified by bioinformatics and RT-qPCR.The results showed that TCS gene smrAB was located upstream of ECF-sig25,and the phosphorylation of SmrA depended solely on SmrB.Stress tests showed that Sig25 responded to high pH,osmotic stress,SDS and heat stress,but not to oxidative stress,acid stress and EDTA stress.Bioinformatic prediction,RT-qPCR and electrophoretic mobility shift assay(EMSA)results revealed that Sig25 directly regulated transcription of whiG,SAV3434,SAV4621,SAV5010,SAV6537,gdhA1,glnA2 and amtB1,which were involved in morphological development,methyl group supply,DNA replication,signal transduction,secondary metabolism and nitrogen metabolism.The plate culture showed that deletion of sig25 had no effect on morphological developmentin of S.avermitilis.