Studies On The Regulation Mechanism Of Oligomycin Biosynthesis In Streptomyces Pactum Act12

Biological control is conducive to environmental protection and is one of the main technologies for sustainable agricultural development.However,most native biocontrol strains have insufficient field application activity,making the large-scale application of pesticides still irreplaceable.To solve this problem,it is necessary to explore ways to improve its activity through artificial means on the basis of understanding the activity regulation mechanism of biocontrol strains.The subject of this project was a strain of biocontrol bacteria Streptomyces pactum Act12,which could inhibit the growth of a variety of pathogenic fungi,but the principle of bacteriostasis was not clear.The whole genome sequence analysis showed that Act12 contains abundant secondary metabolic synthesis gene clusters.Among them,the oligomycin synthesis gene cluster was responsible for the synthesis of oligomycin,which has the effect of inhibiting the growth of fungi.Using bioinformatics methods to discover transcription factors that regulate oligomycin biosynthesis.The method of conjugation transfer and homologous recombination were used to construct deletion and high expression strains.Through antibacterial test,high performance liquid chromatography detection,transcriptome analysis and other methods,the relationship between the antibacterial activity of Act12 and the production of oligomycin was explored,and the oligomycin production was analyzed.The regulation mechanism of oligomycin synthesis was explored.The main results were as follows:The research results showed that there was a very strong correlation between the antibacterial activity of Act12 and the synthesis efficiency of oligomycin.The higher the yield of oligomycin,the stronger the antibacterial activity.The transcription factor 7074 of the Tet R family could inhibit the synthesis of oligomycin by inhibiting the transcription of the cf235 gene of the Crp family.The global regulatory factor AdpA-s could promote the synthesis of oligomycin,but the synthesis of oligomycin would not be affected when it was deleted.The synthesis of oligomycin strictly depended on the presence of the pathway-specific regulator Lux R-2306,and the transcription of its core synthetase genes were positively regulated by Lux R-2306.At the same time,there was a positive feedback regulation relationship between AdpA-s and Lux R-2306.Therefore,we suspected that Lux R-2306 was accumulated through positive feedback between AdpA-s and Lux R-2306.A large amount of Lux R-2306 promoted the transcription of the oligomycin core synthase genes and accelerated the synthesis of oligomycin.This study initially revealed the regulation mechanism of oligomycin synthesis,provided a theoretical reference for improving the synthesis efficiency of similar secondary metabolites,and provided a theoretical basis for improving the biocontrol efficiency.