Identification And Characterization Of Autolysis-related Genes In Lysobacter Enzymogenes OH11

The Lysobacter enzymogenes OH11 strain inhibits the growth of many plant pathogenic bacteria.The secondary metabolites from OH11,heat-stable antifungal factor?HSAF?,could inhibit the growth of phytopathogenic fungi and oomycetes.Because of the large HSAF genes cluster,it could not be expressed in Escherichia coli;the chemical structure of HSAF is complex and could not be synthesized artificially.Therefore,the key steps of improving the HSAF production are genetic-editing key factors and studying regulation mechanism of the HSAF biosynthesis in Lysobacter enzymogenes OH11.In this study,we foucused on the autolysis genes in OH11,and tried to explain the relationship between autolysis and HSAF production.In the previous study,OH11 could grow to OD₆₀₀?3.0-3.5 in nutrient-rich medium?100%TSB?,but gradually decrease after the OD₆₀₀ reaches 2.0 in the auxotrophic medium?10%TSB?.Base on this phenomenon,total gene expressiones were comparied under different nutrient conditions by using transcriptome sequencing and homologous comparisons;and found nine candidates genes.Nine gengs were knock-outed separatly and analyzed the auto-solubility in mutants and wildtype.The reuslts were shown that the konck out of 0714,1014,2162,2703,2875,3671,4232 and 4751 did not affect the autolysis,but decreased the HSAF production,and the regulation mechanism was unknown;the konck out of 0714,1014,2162,2703,2875,3671,4232,4745 and 4751 did not affect the production of protease,cellulase,chitinase,beta-1,3-glucanase and twitching motility;the 2703,3671,4232,4745 and 4751 were involved in colony morphology formation in Lysobacter enzymogenes,and the mechanism was unknown.