Study On The Genes YycF,yvcQ And YvqE Of Two-component Signal Transduction System In Bacillus Thuringiensis BMB171

Bacillus thuringiensis(Bt),which is widely distributed in soil,is a low GC content gram-positive bacterium used worldwide as a biopesticide.Two-component signal transduction system(TCS),typically consisted of histidine kinase(HK)and response regulator(RR),is a class of signal transduction system which widely presents in eukaryotic and prokaryotic cells.In bacteria,TCS plays an important role in responsing to intra-and extracellular stimuli.By combining bioinformatics and experimental methods,this study has mainly completed the following works:1)We comprehensively analyzed the distributions,structures,homologies and putative evolutionary biological functions of all annotated TCS in 11 B.thuringiensis strains with whole genome fully sequenced.2)In B.thuringiensis BMB171,we constructed a strain HB171,which overpresses a RR gene yycF.Compared with the strain HB172(BMB171 carrying a expression plasmid pHT1k-Phj3),the growth and biofilm formation of strain HB171 were inhibited to different degrees.In addition,HB171 can produce more spores in the early stationary phase than that of HB172 which indicates that YycF could facilitate the sporulation of B.thuringiensis.3)We successfully constructed two HK genes yvcQ and yvqE deletion mutants(HB173 and HB174)from BMB171.The growth and cell morphology of both HB173 and HB174 strains were not affected;however,the HB173 strain,which yvcQ was knocked-out,was observed to inhibit the cellular growth and biofilm formation in a high-salt environment,and the missing of yvqE exhibited significantly decreased resistance to vancomycin.This study lays the foundation for future researches focusing on signal regulation of B.thuringiensis.