MarR-Family Transcription Factor HpaR Controls Expression of the vgrR-vgrS Operon of Xanthomonas campestris pv. campestris

Self Cite

Gamma‐proteobacteria Xanthomonas spp. cause at least 350 different plant diseases among important agricultural crops, which result in serious yield losses. Xanthomonas spp. rely mainly on the type III secretion system (T3SS) to infect their hosts and induce a hypersensitive response in nonhosts. HrpG, the master regulator of the T3SS, plays the dominant role in bacterial virulence. In this study, we used chromatin immunoprecipitation followed by sequencing (ChIP‐seq) and tandem affinity purification (TAP) to systematically characterize the HrpG regulon and HrpG interacting proteins in vivo. We obtained 186 candidate HrpG downstream genes from the ChIP‐seq analysis, which represented the genomic‐wide regulon spectrum. A consensus HrpG‐binding motif was obtained and three T3SS genes, hpa2, hrcU, and hrpE, were confirmed to be directly transcriptionally activated by HrpG in the inducing medium. A total of 273 putative HrpG interacting proteins were identified from the TAP data and the DNA‐binding histone‐like HU protein of Xanthomonas campestris pv. campestris (HUxcc) was proved to be involved in bacterial virulence by increasing the complexity and intelligence of the bacterial signalling pathways in the T3SS.

“…The protocol used for ChIP followed that of a previous study (Pan et al , ). Briefly, bacterial strains were grown in NYG medium until OD 600 = 0.4 ± 0.05.…”

Section: Methodsmentioning

confidence: 99%

Analysis of HrpG regulons and HrpG‐interacting proteins by ChIP‐seq and affinity proteomics in Xanthomonas campestris

Zhang

Wei

Qian

et al. 2020

Self Cite

“…campestris and X. citri subsp. citri, where the use of the pHM1-derived plasmids has been reported in prior studies (Chengid et al, 2019;Pan et al, 2018;Zhou et al, 2018).…”

Section: Discussionmentioning

confidence: 99%

An improved, versatile and efficient modular plasmid assembly system for expression analyses of genes in Xanthomonas oryzae

Zou

Zhang

et al. 2021

Xanthomonas oryzae pathovars oryzae (Xoo) and oryzicola (Xoc) infect rice, causing bacterial blight and bacterial leaf streak, respectively, which are two economically important bacterial diseases in paddy fields. The interactions of Xoo and Xoc with rice can be used as models for studying fundamental aspects of bacterial pathogenesis and host tissue specificity. However, an improved vector system for gene expression analysis is desired for Xoo and Xoc because some broad host range vectors that can replicate stably in X. oryzae pathovars are low‐copy number plasmids. To overcome this limitation, we developed a modular plasmid assembly system to transfer the functional DNA modules from the entry vectors into the pHM1‐derived backbone vectors on a high‐copy number basis. We demonstrated the feasibility of our vector system for protein detection, and quantification of virulence gene expression under laboratory conditions and in association with host rice and nonhost tobacco cells. This system also allows execution of a mutant complementation equivalent to the single‐copy chromosomal integration system and tracing of pathogens in rice leaf. Based on this assembly system, we constructed a series of protein expression and promoter‐probe vectors suitable for classical double restriction enzyme cloning. These vector systems enable cloning of all genes or promoters of interest from Xoo and Xoc strains. Our modular assembly system represents a versatile and highly efficient toolkit for gene expression analysis that will accelerate studies on interactions of X. oryzae with rice.

“…The resulting p values were adjusted using the Benjamini and Hochberg's approach for controlling the false discovery rate. Genes with an adjusted p value <.05 found by DESeq were assigned as differentially expressed (Pan et al , ).…”

Section: Methodsmentioning

confidence: 99%

“…Gene ontology enrichment analysis of the DEGs was implemented by the goseq R package, in which the gene length bias was corrected. GO terms with a corrected p value less than .05 were considered significantly enriched by the DEGs (Pan et al , ).…”

Section: Methodsmentioning

confidence: 99%

A LuxR‐type regulator, AcrR, regulates flagellar assembly and contributes to virulence, motility, biofilm formation, and growth ability of Acidovorax citrulli

Guan

Wang

Huang

et al. 2020

LuxR‐type regulators regulate many bacterial processes and play important roles in bacterial motility and virulence. Acidovorax citrulli is a seedborne bacterial pathogen responsible for bacterial fruit blotch, which causes great losses in melon and watermelon worldwide. We identified a LuxR‐type, nonquorum sensing‐related regulator, AcrR, in the group II strain Aac‐5 of A. citrulli. We found that the acrR mutant lost twitching and swimming motilities, and flagellar formation. It also showed reduced virulence, but increased biofilm formation and growth ability. Transcriptomic analysis revealed that 394 genes were differentially expressed in the acrR mutant of A. citrulli, including 33 genes involved in flagellar assembly. Our results suggest that AcrR may act as a global regulator affecting multiple important biological functions of A. citrulli.