Mycobacteriophage SWU1 Early Gene Gp53 Changes The Host Mycobacterium Physiology Via Repressing The Transcription Of Trehalose Metabolism Key Gene Maltose Transferase GlgE

Tuberculosis(TB),casued by Mycobacterium tuberculosis(Mtb),remains a major global public health threat and one of the top ten causes of death worldwide.According to the World Health Organization(WTO),more people have died of tuberculosis than AIDS.Tuberculosis ranks the first mortality caused by a single pathogen.In 2017,the number of TB deaths worldwide was 1.3 million,of which two-thirds were in developing countries.With the emergence and spread of multidrug-resistant(MDR)tuberculosis,extensively drug-resistant(XDR)tuberculosis and even totally drug-resistant(TDR)tuberculosis,as well as human immunodeficiency(HIV)co-infection,the task of tuberculosis prevention and control is arduous.As a promising alternative or adjuvant treatment,phage therapy has renewed public concern.Although studies on bacteriophage therapy have stagnated due to the discovery of antibiotics,the potential of bacteriophages in the treatment of bacterial infections is unlimited.Engineering bacteriophages targeting key genes of bacterial gene regulatory network can be used as antibiotic adjuvants to enhance the bactericidal efficacy of antibiotics.Phage reduces the formation of biofilm of multidrug-resistant Pseudomonas aeruginosa and destroys its drug resistance barrier.Phage display technology is of great significance for the development of new vaccines and the treatment of tumors.Trehalose is a non-reducible disaccharide widely existing in various organisms except human.It is ubiquitous and plays an important role in microorganisms.The key enzymes involved in trehalose metabolism are ideal new candidate targets for antibiotics.Many important substances in Mtb,such as cell wall glycolipids,cord factors and thiolipids,contain trehalose.Mycobacterial trehalose synthesis mainly through two pathways,OtsAB and TreYZ.Trehalose can be converted into a branched glucan with ?-1,4 and ?-1,6 glycosidic bonds through ?-glucan pathway,providing materials for the formation of capsule and methyl-glucose lipopolysaccharide.When the genes encoding trehalose phosphatase(otsB)or maltose transferase(glgE)are inhibited,the accumulated phosphate sugar is toxic to cells.These two genes may be ideal drug targets.In this study,we explored the effect and molecular mechanism of mycobacteriophage SWU1 gene gp53 on host bacteria.The gp53 is unique to Mycobacteriophage SWU1,and there is no homologous gene even in the highly similar bacteriophage L5.Trehalose helps cells against extreme environmental conditions such as extreme temperatures and low pH.Ms_gp53 strains could not grow on the medium with trehalose as the sole carbon source,and biofilm folds increased.When trehalose was added,the single colony edge of Ms_gp53 strain lacked web-like structure,the bacteria became shorter and more sensitive to vancomycin.qRT-PCR detection revealed that the transcription of glgE,a key gene in trehalose metabolism pathway,was inhibited.This leads to the accumulation of maltose phosphate,which is toxic to bacteria.This also explains that the Ms_gp53 can not grow in the medium with trehalose as the sole carbon source.TLC detection showed that the carbohydrates of Ms_gp53 changed.In summary,we first found that mycobacteriophage SWU1 gene gp53 inhibited the transcription of glgE,a key gene in trehalose decomposition pathway,resulting in trehalose sensitivity of bacteria,which provides a new idea for drug research with glgE as an antimicrobial target.