Glaesserella parasuis is the causative agent of Gl?sser's disease in pigs.However,the pathogenic mechanisms underlying its virulence is not yet fully understood.The RuvB protein,a member of the AAA+superfamily,is implicated in various cellular processes,yet its specific role in the virulence of Glaesserella parasuis has not been fully characterized.In this study,we con-structed a RuvB gene deletion mutant,designated ΔRuvB,using the serotype 13 Glaesserella pa-rasuis strain ZJ1208 and a suicide plasmid-mediated natural transformation approach.To elucidate the functional role of the RuvB gene,we comprehensively evaluated the biological characteristics of the ΔRuvB strain through a series of assays,including growth kinetics,colony morphology,bac-terial staining,transmission electron microscopy(TEM),osmotic stress tolerance,high-tempera-ture tolerance,heat shock resistance,UV resistance,capsular polysaccharide quantification,serum bactericidal assays,and murine virulence experiments.Our findings revealed that the growth rate of ΔRuvB showed no significant difference compared to the parental strain.TEM revealed a notable increase in bacterial cell length;however,the number of outer membrane vesicles(OMVs)on the surface of ΔRuvB did not significantly increase.Notably,the ΔRuvB strain displayed a significant reduction in capsular polysaccharide production and serum resistance,as well as diminished toler-ance to UV radiation and high temperatures.Significant alterations were observed in its resistance to osmotic stress or oxidative stress.In the mouse toxicity challenge experiment,in com-parison with the parental strain ZJ1208,the mortality rate dropped by 20 percentage points,suggesting that the virulence of ΔRuvB has been weakened to some extent.Collectively,these results underscore the critical role of the RuvB gene in enhancing the environmental adaptability of Glaesserella parasuis.

Glaesserella parasuis is the causative agent of Gl?sser's disease in pigs.However,the pathogenic mechanisms underlying its virulence is not yet fully understood.The RuvB protein,a member of the AAA+superfamily,is implicated in various cellular processes,yet its specific role in the virulence of Glaesserella parasuis has not been fully characterized.In this study,we con-structed a RuvB gene deletion mutant,designated ΔRuvB,using the serotype 13 Glaesserella pa-rasuis strain ZJ1208 and a suicide plasmid-mediated natural transformation approach.To elucidate the functional role of the RuvB gene,we comprehensively evaluated the biological characteristics of the ΔRuvB strain through a series of assays,including growth kinetics,colony morphology,bac-terial staining,transmission electron microscopy(TEM),osmotic stress tolerance,high-tempera-ture tolerance,heat shock resistance,UV resistance,capsular polysaccharide quantification,serum bactericidal assays,and murine virulence experiments.Our findings revealed that the growth rate of ΔRuvB showed no significant difference compared to the parental strain.TEM revealed a notable increase in bacterial cell length;however,the number of outer membrane vesicles(OMVs)on the surface of ΔRuvB did not significantly increase.Notably,the ΔRuvB strain displayed a significant reduction in capsular polysaccharide production and serum resistance,as well as diminished toler-ance to UV radiation and high temperatures.Significant alterations were observed in its resistance to osmotic stress or oxidative stress.In the mouse toxicity challenge experiment,in com-parison with the parental strain ZJ1208,the mortality rate dropped by 20 percentage points,suggesting that the virulence of ΔRuvB has been weakened to some extent.Collectively,these results underscore the critical role of the RuvB gene in enhancing the environmental adaptability of Glaesserella parasuis.