The Study On SigX Factor In Bacillus Controlling Tomato Bacterial Wilt And Banana Fusarium Wilt

Bacillus amyloliquefaciens is a kind of Plant Growth Promoting Rhinoacteria rhizosphere(PGPR),which has preventive and therapeutic effect on kinds of plant pathogens.Extracellular functional factor,as a bacterial transcription regulator,can respond to stress responses.It’s vital significant to explore the function of extracellular function(ECF)in the biological control of plant pathogens in PGPR.In this study,we explored the function of sigX deletion mutant strain in the prevention and control of the banana fusarium wilt and tomato bacterial wilt tablets antibacterial ability,the capacity of lipidpeptide antibiotics,soil survival ability,the ability of biofilm formation and movement as well as the ability of root colonization of the sigX deletion mutant strain was explored respectively.Finally,the efficiency of biological control of sigX deletion mutant strain was verified by pot experiment.The results are as follows.(1)The efficiency of the sigX deletion mutant strain to control banana wilt and tomato bacterial wilt was reduced,indicating that sigX was involved in the prevention and tcontrol of banana wilt and tomato bacterial wilt.(2)The antimicrobial diameters of wild type 118 and sigX deletion strain of banana wilt were 8.7 mm and 8.5 mm respectively.The bacteriostatic diameters of Ralstonia Solanacearum were 10 mm and 9.1 mm respectively,there was no significant difference.Further,UPLC-MS was used to detect the lipidpeptide antibiotics,it showed that both wild-type and sigX deletion mutant strain could produce three kinds of lipidpeptide compounds: surfactin、iturin、fengycin.It was shown that sigX was not involved in the regulation of the lipopeptide antibiotic metabolites of Bacillus amyloidosis.(3)Under the microcosmic soil culture,sigX deletion mutation can survive and grow well in soil.Liquid solid LBGM were used to test the biofilm formation ability of the Bacillus amyloliquefacien 118 and the sigX deletion mutant strain.The results showed that sigX deletion mutant strain’s ability to forme biofilm was weaker,and the speed of forming biofilm was slower,the biofilm was thin and transparent.The swimming and peristalsis ability of Bacillus amyloliquefacien 118 and the sigX deletion mutant strain were detected by the LBGM culture conditions of 0.3% and 0.7% agar powder,the swimming and peristalsis speed of sigX deletion mutant strain was significantly reduced.(4)The ability to colonize roots of Bacillus amyloliquefacien 118 and sigX deletion mutant strain were detected.The results showed that sigX deletion mutant strain colonized more slower compared with wild type,and the colonization ability was weaker.In conclusion,sigX in bacillus plays an important role in the process of colonizing plant roots,sigX can regulate the biofilm formation and the speed of swimming,peristalsis,root colonization ability of Bacillus,finally it can affect biological control ability of bacillus.