The Zur of Xanthomonas campestris Is Involved in Hypersensitive Response and Positively Regulates the Expression of the hrp Cluster Via hrpX But Not hrpG

Huang, Dongliang; Tang, Dongjie; Liao, Qing; Li, Xiaoqian; He, Yanan; Feng, Jia‐Xun; Jiang, Bo-Le; Lu, Guang‐Tao; Tang, Ji‐Liang

doi:10.1094/mpmi-22-3-0321

Cited by 57 publications

(76 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Similarly, accumulating evidence indicates that HrpX regulates the expression of genes not only with the perfect PIP-box but also without such the PIP-box (Wei et al 2007;Chao et al 2008;Zhang et al 2008;Huang et al 2009). The newly identiWed HrpX regulon genes via a GFP visualization technique in this report, kgtP with an imperfect PIP-box and Z1234 without the PIPbox, will certainly serve as the model to screen more HrpX regulon genes in Xanthomonas species.…”

Section: Discussionmentioning

confidence: 95%

“…However, other methods, like RT-PCR and qRT-PCR, can be used to Wrst verify the diVerential expression of an HrpX regulon candidate between the wild-type strain and the hrpX mutant of Xoc. Compared with the Cya reporter system (Casper-Lindley et al 2002;Cunnac et al 2004;Schechter et al 2006), the Avr reporter strategy (Guttman and Greenberg 2001;Roden et al 2004;Jiang et al 2009a, b), and the gusA reporter method (Wei et al 2007;Chao et al 2008;Zhang et al 2008;Huang et al 2009;Mukaihara et al 2010), the GFP visualization technique for HrpX regulon gene identiWcation is a direct tool in which the gfp gene is used as a reporter and rice cells are used as the substrate to mimic Xoc infection in rice. A translation fusion of gfp reporter with promoter region plus the putative N-terminal secretion signal coding sequence of a candidate gene may help to identify T3SEs of Xoc under interaction with rice cells.…”

Section: Discussionmentioning

confidence: 99%

“…The N-terminal domain of identiWed T3SEs contains more than 20% Ser and Pro residues in the Wrst 50 aa, as revealed in Xoo (Furutani et al 2009) and R. solanacearum (Cunnac et al 2004), and has more than 5 Ser residues, as reXected in P. syringae (Alfano and Collmer 2004;Schechter et al 2006;Tampakaki et al 2004). The transcription and translocation of HrpX regulon candidates have been examined using several reporter systems, such as calmodulin-dependent adenylate cyclase (Cya) from Bordetella pertussis (Casper-Lindley et al 2002;Cunnac et al 2004;Schechter et al 2006), gusA (Wei et al 2007;Chao et al 2008;Zhang et al 2008;Huang et al 2009) and avirulence gene products (e.g., AvrBs1) lacking the T3S signal sequence (Roden et al 2004;Jiang et al 2009a, b). Additionally, eVectors were identiWed by random insertion with transposons containing avirulence (avr) genes that lack the secretion signal followed by an Avr-based assay for the translocation of gene products fused with Avr into plant cells.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Identification of HrpX regulon genes in Xanthomonas oryzae pv. oryzicola using a GFP visualization technique

Xiao

Zou

et al. 2011

Arch Microbiol

View full text Add to dashboard Cite

Xanthomonas oryzae pv. oryzicola is the causal agent of bacterial leaf streak in rice and injects repertoires of T3S effectors (T3SEs), which are normally regulated by a global regulator HrpX, into plant cells to suppress plant innate immunity for disease development. To establish a visualization technique to identify HrpX regulon genes in this pathogen, we chose six known or unknown T3SE genes of X. oryzae pv. oryzicola (strain RS105) as the targets in this report. The promoters of these candidates, whether or not containing a PIP-box, were fused with the gfp (green fluorescent protein) reporter gene, and the gfp reporters were introduced into the wild-type RS105 and the hrpX mutant RΔhrpX. GFP expression in the wild-type strain could be observed under fluorescence microscopy, but fluorescence was not observed in the hrpX mutant. Consequently, transcription and secretion detection demonstrated that these HrpX regulon members were repressed when hrpX was mutated and were not secreted into the hrp-inducing medium XOM3 because of a mutation in hrcV (T3SS deficient). These data suggest that the gfp reporter system is a feasible visualization tool for the identification of HrpX regulon genes and discovery of new T3SEs in the X. oryzae pv. oryzicola-rice pathosystem.

show abstract

Section: Discussionmentioning

confidence: 95%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Identification of HrpX regulon genes in Xanthomonas oryzae pv. oryzicola using a GFP visualization technique

Xiao

Zou

et al. 2011

Arch Microbiol

View full text Add to dashboard Cite

show abstract

“…ColS/ColR constitute a TCS that is implicated in virulence and HR in planta; these proteins were shown to repress the expression of hrpG and the hrpC and hrpE operons but not other hrp genes (45,46). Zur, a key regulator for zinc homeostasis, positively influenced the expression of hrp operons via hrpX but not hrpG (47). HpaR1 is a GntR family transcriptional activator that regulates the expression of all five operons in the hrp cluster via HrpG (48).…”

Section: Discussionmentioning

confidence: 99%

HrcT Is a Key Component of the Type III Secretion System in Xanthomonas spp. and Also Regulates the Expression of the Key hrp Transcriptional Activator HrpX

Liu

Zou

Xue

et al. 2014

Appl Environ Microbiol

View full text Add to dashboard Cite

The type III secretion system (T3SS), encoded by hrp (hypersensitive response and pathogenicity) genes in Gram-negative phytopathogenic bacteria, delivers repertoires of T3SS effectors (T3SEs) into plant cells to trigger the hypersensitive response (HR) in nonhost or resistant-host plants and promote pathogenicity in susceptible plants. The expression of hrp genes in Xanthomonas is regulated by two key regulatory proteins, HrpG and HrpX. However, the interactions between hrp gene products in directing T3SE secretion are largely unknown. Here we demonstrated that HrcT of X. oryzae pv. oryzicola functions as a T3SS component and positively regulates the expression of hrpX. Transcription of hrcT occurs via two distinct promoters; one (T1) is with the hrpB operon and the second (T3) within hrpB7 Via either promoter T1 or T3, the defect in Hrp phenotype by hrcT deletion was corrected in the presence of hrcT only from Xanthomonas species but not from other phytopathogenic bacteria. An N-terminally truncated HrcT was able to bind the hrpX promoter and activate the expression of hrpX, supporting that HrcT is a positive regulator of hrpX. A revised model showing the regulatory interactions between HrcT, HrpX, and HrpG is proposed.

show abstract

“…campestris. For phytopathogenic bacteria, the HrpG/HrpX regulon responds to the surrounding environment and aids in the nutrient uptake process (16,33). An acidic pH, low osmotic pressure, and nutritional limitations are thought to partly contribute to the induction of the hrp and hrc genes (30).…”

Section: Discussionmentioning

confidence: 99%

Synergistic Activation of the Pathogenicity-Related Proline Iminopeptidase Gene in Xanthomonas campestris pv. campestris by HrpX and a LuxR Homolog

Zhang

Kan

Zhang

et al. 2012

Appl Environ Microbiol

View full text Add to dashboard Cite

c Xanthomonas campestris pv. campestris strain 8004 contains an orphan quorum-sensing (QS) locus, xccR-pip Xcc , in which the proline iminopeptidase (pip Xcc ) gene (where "Xcc" indicates that the pip gene is from X. campestris pv. campestris) is positively regulated by the LuxR homologue XccR by binding to the luxXc box of the pip Xcc promoter. The disruption of pip Xcc significantly attenuated the virulence of X. campestris pv. campestris. An imperfect plant-inducible promoter (PIP) box is located in the upstream region of the pip Xcc promoter, which is the putative binding site of the transcriptional activator HrpX. To explore whether the expression of the pip Xcc gene is regulated by HrpX, the expression level of a pip Xcc promoter-gusA fusion gene was assayed in an hrpX disruption mutant. The results showed that the lack of HrpX dramatically decreased the ␤-glucuronidase (GUS) activity. Further analyses using an electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP)-PCR indicated that the imperfect PIP box in X. campestris pv. campestris is specifically bound to HrpX. These data demonstrated that the pip Xcc gene belongs to the hrp regulon and that the imperfect PIP box of the pip Xcc promoter could be a cis element for the HrpX protein. We further showed in a pulldown assay that XccR can bind HrpX, suggesting that these two regulatory proteins coactivate the virulence factor by binding to the different cis elements of the pip Xcc gene and adapt to the host environment during X. campestris pv. campestris infection.

show abstract

The Zur of Xanthomonas campestris Is Involved in Hypersensitive Response and Positively Regulates the Expression of the hrp Cluster Via hrpX But Not hrpG

Cited by 57 publications

References 48 publications

Identification of HrpX regulon genes in Xanthomonas oryzae pv. oryzicola using a GFP visualization technique

Identification of HrpX regulon genes in Xanthomonas oryzae pv. oryzicola using a GFP visualization technique

HrcT Is a Key Component of the Type III Secretion System in Xanthomonas spp. and Also Regulates the Expression of the Key hrp Transcriptional Activator HrpX

Synergistic Activation of the Pathogenicity-Related Proline Iminopeptidase Gene in Xanthomonas campestris pv. campestris by HrpX and a LuxR Homolog

Contact Info

Product

Resources

About