Function of DeoR family transcription factor glpR in Acidovorax citrulli
The DeoR(Deoxyribonucleoside operon repressor)family of transcription factors are transcriptional regulators that are widely present in prokaryotes.DeoR affects the pathogenicity of pathogenic bacteria by regulating the expression of virulence factors,and there are different regulatory networks in different pathogenic bacteria.In order to elucidate its function and signaling pathway in Acidovorax citrulli,Aac5 strain was used to construct the deletion mutant and comple-mentary strain of DeoR transcription factor glpR.The function of DeoR transcription factor glpR in Acidovorax citrulli was preliminarily explored by measuring the phenotype and transcription level.The results showed that after deletion of glpR gene,the ability of Aac5 strain to utilize fructose,the pathogenicity of watermelon seedlings,the growth ability of watermelon cotyledons and the ability to form biofilm were significantly decreased,and the growth rate in vitro was slowed down.The ability to resist high salt stress and copper ion stress was significantly increased.At the same time,the deletion of the gene glpR resulted in a significant down-regulation of the type Ⅲ secretion system genes hrpG,hrpE and hrcJ,a significant down-regulation of the fructose utilization-related genes fruA,fruB and fruK,and a significant down-regulation of the biofilm-related gene flgG.Compared with WT-fruBpGUS,the promoter activity of fruB in Agl-pR-fruBpGUS was significantly reduced.The results indicated that glpR gene plays an important role in fructose utiliza-tion,resistance to stress and pathogenicity of Acidovorax citrulli.