scholarly journals 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

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.

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

2019 ◽  
Vol 8 (1) ◽  
pp. 45 ◽  
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.

scholarly journals Identification of FadT as a Novel Quorum Quenching Enzyme for the Degradation of Diffusible Signal Factor in Cupriavidus pinatubonensis Strain HN-2

2021 ◽  
Vol 22 (18) ◽  
pp. 9862
Author(s):  
Xudan Xu ◽  
Tian Ye ◽  
Wenping Zhang ◽  
Tian Zhou ◽  
Xiaofan Zhou ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Xanthomonas Campestris ◽  
Cell Communication ◽  
Maximal Activity ◽  
Quorum Quenching ◽  
Site Directed Mutagenesis ◽  
Diffusible Signal Factor ◽  
High Enzymatic Activity ◽  
Xanthomonas Campestris Pv Campestris ◽  
Potential Use

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.

Involvement of a novel peroxidase isozyme and lignification in hydathodes in resistance to black rot disease in cabbage

2000 ◽  
Vol 78 (9) ◽  
pp. 1144-1149 ◽  
Author(s):  
P A Gay ◽  
S Tuzun
Keyword(s):  
Xanthomonas Campestris ◽  
Virulent Strain ◽  
Black Rot ◽  
Peroxidase Isozyme ◽  
Anionic Peroxidase ◽  
Peroxidase Isozymes ◽  
Resistant Varieties ◽  
Rot Disease ◽  
Xanthomonas Campestris Pv Campestris ◽  
Lignin Deposition

The physiological mechanisms associated with resistance of cabbage to black rot disease seem to be associated with the hydathodes. To investigate the role of hydathodes in disease resistance, total peroxidase activities, anionic peroxidase isozyme expression, and lignin deposition were determined in hydathodes of resistant (Hancock and Green Cup), partially resistant (Cheers), and susceptible (Strukton and Perfect Ball) cabbage varieties (Brassica oleracea L.) during pathogenesis with Xanthomonas campestris pv. campestris. Four-week-old plants were petiole-inoculated with a highly virulent strain of X. campestris pv. campestris (FD91L). Hydathodal fluids were collected daily over a 14-day period from infected plants as well as noninfected, mock-inoculated control plants. Hydathodal fluids of resistant varieties had greater peroxidase activity when compared to susceptible ones, with infected plants having higher peroxidase levels than noninfected plants. Isoelectric focusing revealed the presence of four anionic peroxidase isozymes in hydathodal fluids, with the most anionic one (pI of 3.6) accumulating only upon infection. Lignin deposition in and around the hydathodes was associated with the accumulation of this particular isozyme in hydathodal fluids. The evidence suggests that a rapid, systemic response is associated with resistance to the bacterial pathogen.Key words: peroxidases, hydathodes, isozymes, black rot disease, cabbage, Xanthomonas campestris pv. campestris.

scholarly journals Quorum Quenching in a Novel Acinetobacter sp. XN-10 Bacterial Strain against Pectobacterium carotovorum subsp. carotovorum

2020 ◽  
Vol 8 (8) ◽  
pp. 1100 ◽  
Author(s):  
Wenping Zhang ◽  
Qingqing Luo ◽  
Yiyin Zhang ◽  
Xinghui Fan ◽  
Tian Ye ◽  
...  
Keyword(s):  
Bacterial Pathogens ◽  
Quorum Quenching ◽  
Homoserine Lactone ◽  
Gas Chromatography Mass Spectrometry ◽  
Pectobacterium Carotovorum ◽  
Degrading Bacterium ◽  
Family Analysis ◽  
Carotovorum Subsp ◽  
Acinetobacter Sp ◽  
Tissue Maceration

Quorum sensing (QS) is a cell density-dependent mechanism that regulates the expression of specific genes in microbial cells. Quorum quenching (QQ) is a promising strategy for attenuating pathogenicity by interfering with the QS system of pathogens. N-Acyl-homoserine lactones (AHLs) act as signaling molecules in many Gram-negative bacterial pathogens and have received wide attention. In this study, a novel, efficient AHL-degrading bacterium, Acinetobacter sp. strain XN-10, was isolated from agricultural contaminated soil and evaluated for its degradation efficiency and potential use against QS-mediated pathogens. Strain XN-10 could effectively degrade N-(3-oxohexanoyl)-L-homoserine lactone (OHHL), N-hexanoyl-L-homoserine lactone (C6HSL), N-(3-oxododecanoyl)-L-homoserine lactone (3OC12HSL), and N-(3-oxooctanoyl)-L-homoserine lactone (3OC8HSL), which all belong to the AHL family. Analysis of AHL metabolic products by gas chromatography–mass spectrometry (GC-MS) led to the identification of N-cyclohexyl-propanamide, and pentanoic acid, 4-methyl, methyl ester as the main intermediate metabolites, revealing that AHL could be degraded by hydrolysis and dehydroxylation. All intermediates were transitory and faded away without any non-cleavable metabolites at the end of the experiment. Furthermore, strain XN-10 significantly attenuated the pathogenicity of Pectobacterium carotovorum subsp. carotovorum (Pcc) to suppress tissue maceration in carrots, potatoes, and Chinese cabbage. Taken together, our results shed light on the QQ mechanism of a novel AHL-degrading bacterial isolate, and they provide useful information which show potential for biocontrol of infectious diseases caused by AHL-dependent bacterial pathogens.

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