Acinetobacter lactucae Strain QL-1, a Novel Quorum Quenching Candidate Against Bacterial Pathogen Xanthomonas campestris pv. campestris

Quorum sensing (QS) is a microbial cell–cell communication mechanism and plays an important role in bacterial infections. QS-mediated bacterial infections can be blocked through quorum quenching (QQ), which hampers signal accumulation, recognition, and communication. The pathogenicity of numerous bacteria, including Xanthomonas campestris pv. campestris (Xcc), is regulated by diffusible signal factor (DSF), a well-known fatty acid signaling molecule of QS. Cupriavidus pinatubonensis HN-2 could substantially attenuate the infection of XCC through QQ by degrading DSF. The QQ mechanism in strain HN-2, on the other hand, is yet to be known. To understand the molecular mechanism of QQ in strain HN-2, we used whole-genome sequencing and comparative genomics studies. We discovered that the fadT gene encodes acyl-CoA dehydrogenase as a novel QQ enzyme. The results of site-directed mutagenesis demonstrated the requirement of fadT gene for DSF degradation in strain HN-2. Purified FadT exhibited high enzymatic activity and outstanding stability over a broad pH and temperature range with maximal activity at pH 7.0 and 35 °C. No cofactors were required for FadT enzyme activity. The enzyme showed a strong ability to degrade DSF. Furthermore, the expression of fadT in Xcc results in a significant reduction in the pathogenicity in host plants, such as Chinese cabbage, radish, and pakchoi. Taken together, our results identified a novel DSF-degrading enzyme, FadT, in C. pinatubonensis HN-2, which suggests its potential use in the biological control of DSF-mediated pathogens.

Download Full-text

Complete Genome Sequence of Strain WHRI 3811 Race 1 of Xanthomonas campestris pv. campestris, the Causal Agent of Black Rot of Cruciferous Vegetables

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-07-19-0177-a ◽

2019 ◽

Vol 32 (12) ◽

pp. 1571-1573

Author(s):

Congcong Kong ◽

Vânia Horta de Passo ◽

Zhiyuan Fang ◽

Limei Yang ◽

Mu Zhuang ◽

...

Keyword(s):

Genome Sequence ◽

Single Molecule ◽

Complete Genome Sequence ◽

Complete Genome ◽

Xanthomonas Campestris ◽

Bacterial Pathogen ◽

Black Rot ◽

Cruciferous Vegetables ◽

Race 1 ◽

Xanthomonas Campestris Pv Campestris

Xanthomonas campestris pv. campestris is an important bacterial pathogen that causes black rot and brings about enormous production loss for cruciferous vegetables worldwide. Currently, genome sequences for only a few X. campestris pv. campestris isolates are available, most of which are draft sequences. Based on the next-generation sequencing and single-molecule sequencing in real time technologies, we present here the complete genome sequence of strain WHRI 3811 race 1 of X. campestris pv. campestris, which is a type strain that has been extensively used. The genome data will contribute to our understanding of X. campestris pv. campestris genomic features and pave the way for research on X. campestris pv. campestris–host interactions.

Download Full-text

Cupriavidus sp. HN-2, a Novel Quorum Quenching Bacterial Isolate, is a Potent Biocontrol Agent Against Xanthomonas campestris pv. campestris

Microorganisms ◽

10.3390/microorganisms8010045 ◽

2019 ◽

Vol 8 (1) ◽

pp. 45 ◽

Cited By ~ 8

Author(s):

Tian Ye ◽

Tian Zhou ◽

Qiting Li ◽

Xudan Xu ◽

Xinghui Fan ◽

...

Keyword(s):

Bacterial Infections ◽

Xanthomonas Campestris ◽

Biocontrol Agent ◽

Bacterial Isolate ◽

Bacterial Pathogens ◽

Acid Methyl Ester ◽

Quorum Quenching ◽

Gas Chromatography Mass Spectrometry ◽

Biochemical Basis ◽

Xanthomonas Campestris Pv Campestris

Diffusible signal factor (DSF) represents a family of widely conserved quorum sensing (QS) signals involved in the regulation of virulence factor production in many Gram-negative bacterial pathogens. Quorum quenching, which disrupts QS either by degradation of QS signals or interference of signal generation or perception, is a promising strategy for prevention and control of QS-mediated bacterial infections. In this study, a novel DSF-degrading strain, HN-2, was isolated from contaminated soil and identified as Cupriavidus sp. The isolate exhibited superior DSF degradation activity and completely degraded 2 mmol·L–1 of DSF within 24 h. Analysis of the degradation products of DSF by gas chromatography–mass spectrometry led to the identification of trans-2-decenoic acid methyl ester as the main intermediate product, suggesting that DSF could be degraded by oxidation and hydroxylation. Moreover, this study presents for the first time, evidence that Cupriavidus sp. can reduce the black rot disease caused by Xanthomonas campestris pv. campestris (Xcc). Application of the HN-2 strain as a biocontrol agent could substantially reduce the disease severity. These findings reveal the biochemical basis of a highly efficient DSF-degrading bacterial isolate and present a useful agent for controlling infectious diseases caused by DSF-dependent bacterial pathogens.

Download Full-text

Draft Genome Sequences of Two New Zealand Xanthomonas campestris pv. campestris Isolates, ICMP 4013 and ICMP 21080

Genome Announcements ◽

10.1128/genomea.01247-15 ◽

2015 ◽

Vol 3 (5) ◽

Cited By ~ 5

Author(s):

Dhairyasheel Desai ◽

Jin-Hua Li ◽

Eline van Zijll de Jong ◽

Robert Braun ◽

Andrew Pitman ◽

...

Keyword(s):

New Zealand ◽

Xanthomonas Campestris ◽

Draft Genome ◽

Bacterial Pathogen ◽

Genome Sequences ◽

Specific Factors ◽

Xanthomonas Campestris Pv Campestris

Xanthomonas campestris pv. campestris is a necrotrophic bacterial pathogen of crucifers. We report here the draft genome sequences of isolates ICMP 4013 and ICMP 21080 from New Zealand. These sequences will facilitate the identification of race-specific factors in X. campestris pv. campestris.

Download Full-text

Requirement of a mip-Like Gene for Virulence in the Phytopathogenic Bacterium Xanthomonas campestris pv. campestris

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-20-0021 ◽

2007 ◽

Vol 20 (1) ◽

pp. 21-30 ◽

Cited By ~ 28

Author(s):

Ning Zang ◽

Dong-Jie Tang ◽

Mei-Liang Wei ◽

Yong-Qiang He ◽

Baoshan Chen ◽

...

Keyword(s):

Virulence Factors ◽

Legionella Pneumophila ◽

Xanthomonas Campestris ◽

Bacterial Pathogen ◽

Replication Capacity ◽

Human Pathogens ◽

Extracellular Proteases ◽

Ppiase Activity ◽

Phytopathogenic Bacterium ◽

Xanthomonas Campestris Pv Campestris

Macrophage infectivity potentiators (Mips) are FKBP domain-containing proteins reported as virulence factors in several human pathogens, such as members of genera Legionella, Salmonella and Chlamydia. The putative peptidyl-prolyl cis-trans isomerase (PPIase) encoded by XC2699 of the plant bacterial pathogen Xanthomonas campestris pv. campestris 8004 exhibits a 49% similarity at the aminoacid level to the Mip protein of Legionella pneumophila. This mip-like gene, XC2699, was overexpressed in Es-cherichia coli and the purified (His)6-tagged Mip-like protein encoded by XC2699 exhibited a PPIase activity specifically inhibited by FK-506. A mutation in the mip-like gene XC2699 led to significant reductions in virulence and replication capacity in the host plant Chinese radish (Raphanus sativus L. var. radiculus Pers.). Furthermore, the production of exopolysaccharide and the activity of extracellular proteases, virulence factors X. campestris pv. campestris, were significantly decreased in the mip-like mutant. These results reveal that the mip-like gene is involved in the pathogenesis of X. campestris pv. campestris through an effect on the production of these virulence factors.

Download Full-text

Characterization of a Novel Quorum-Quenching Bacterial Strain, Burkholderia anthina HN-8, and Its Biocontrol Potential against Black Rot Disease Caused by Xanthomonas campestris pv. campestris

Microorganisms ◽

10.3390/microorganisms8101485 ◽

2020 ◽

Vol 8 (10) ◽

pp. 1485

Author(s):

Tian Ye ◽

Wenping Zhang ◽

Zhixuan Feng ◽

Xinghui Fan ◽

Xudan Xu ◽

...

Keyword(s):

Bacterial Infections ◽

Xanthomonas Campestris ◽

Bacterial Pathogens ◽

Quorum Quenching ◽

Gas Chromatography Mass Spectrometry ◽

Black Rot ◽

Degrading Bacterium ◽

Diffusible Signal Factor ◽

Rot Disease ◽

Xanthomonas Campestris Pv Campestris

Diffusible signal factor (DSF) is a type of cis unsaturated fatty acid, with a chemical structure of 11-methyl-2-dodecylene acid. DSF is widely conserved in a variety of Gram-negative bacterial pathogens and is involved in the regulation of pathogenic virulence. Quorum quenching (QQ) is a promising strategy for preventing and controlling quorum sensing (QS)-mediated bacterial infections by interfering with the QS system of pathogens. In this study, a novel DSF-degrading bacterium, Burkholderia anthina strain HN-8, was isolated and characterized for its degradation ability and potential biocontrol of black rot disease caused by Xanthomonas campestris pv. campestris (Xcc). The HN-8 strain exhibited superb DSF degradation activity and completely degraded 2 mM DSF within 48 h. In addition, we present the first evidence of bacterium having a metabolic pathway for the complete degradation and metabolism of DSF. Analysis of DSF metabolic products by gas chromatography–mass spectrometry led to the identification of dodecanal as the main intermediate product, revealing that DSF could be degraded via oxidation–reduction. Furthermore, application of strain HN-8 as a potent biocontrol agent was able to significantly reduce the severity of black rot disease in radishes and Chinese cabbage. Taken together, these results shed light on the QQ mechanisms of DSF, and they provide useful information showing the potential for the biocontrol of infectious diseases caused by DSF-dependent bacterial pathogens.

Download Full-text

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

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-07-17-0187-r ◽

2018 ◽

Vol 31 (3) ◽

pp. 299-310 ◽

Cited By ~ 2

Author(s):

Yue Pan ◽

Fang Liang ◽

Ru-Jiao Li ◽

Wei Qian

Keyword(s):

Xanthomonas Campestris ◽

Pathogenic Bacteria ◽

Bacterial Pathogen ◽

Bacterial Virulence ◽

Promoter Regions ◽

Epistasis Analysis ◽

Depth Analysis ◽

Chromatin Immunoprecipitation Sequencing ◽

Two Component Signal Transduction ◽

Xanthomonas Campestris Pv Campestris

MarR (multiple antibiotic resistance regulator)-family transcription factors (TFs), which regulate the expression of virulence factors and other physiological pathways in pathogenic bacteria, are regarded as ideal molecular targets for the development of novel antimicrobial strategies. In the plant bacterial pathogen Xanthomonas campestris pv. campestris, HpaR, a typical MarR-family TF, is associated with bacterial virulence, but its mechanism of virulence regulation remains unclear. Here, we dissected the HpaR regulon using high-throughput RNA sequencing and chromatin immunoprecipitation sequencing. HpaR directly or indirectly controls the expression of approximately 448 genes; it acts both as a transcriptional activator and a repressor to control the expression of downstream genes by directly binding to their promoter regions. The consensus HpaR-binding DNA motifs contain imperfect palindromic sequences similar to [G/T]CAACAATT[C/T]TTG. In-depth analysis revealed that HpaR positively modulates transcription level of the vgrR-vgrS operon that encodes an important two-component signal transduction system to sense iron depletion and regulate bacterial virulence. Epistasis analysis demonstrated that vgrR-vgrS is a core downstream component of HpaR regulation, as overexpression of vgrR restored the phenotypic deficiencies caused by a hpaR mutation. This dissection of the HpaR regulon should facilitate future studies focused on the activating mechanism of HpaR during bacterial infection.

Download Full-text