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

Abstract

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.

Exploration of the Quorum-Quenching Mechanism in Pseudomonas nitroreducens W-7 and Its Potential to Attenuate the Virulence of Dickeya zeae EC1

“…Among these, the use of QQ bacteria or QQ enzymes has appeared as an efficient tool for managing plant diseases ( Uroz et al, 2009 ). Several QQ strains such as Cupriavidus sp., A. lactucae , Burkholderia anthina , O. intermedium , Bacillus sp., Variovorax sp., Variovorax paradoxus , and A. tumefaciens have been discovered and applied as tools for the biocontrol of plant diseases ( Ha et al, 2018 ; Ye et al, 2019 , 2020b , c ; Fan et al, 2020 ). The expression of QQ hydrolytic enzymes (AttM and AiiA) quenched virulence in the pathogenic bacteria Dickeya spp.…”

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

“…Daily records of symptoms were taken after bacterial inoculation. The macerated area was measured to evaluate the disease severity [15,51].…”

“…Three replicates of each treatment were used, and the experiments were carried out at least thrice. Daily records of symptoms were taken after bacterial inoculation [51,58]. The details of the tests are as follows: The strains used in this part were already cultured in 5 mL LB medium and shaken at 30 • C and 200 rpm for 12-16 h. Then, 100 µL of bacterial suspensions were inoculated on each plant.…”

“…The macerated tissue was measured to evaluate the disease severity. The percentage of maceration was calculated by comparison with the preinoculation tissue [15,51].…”

A plant growth-promoting bacteria Priestia megaterium JR48 induces plant resistance to the crucifer black rot via a salicylic acid-dependent signaling pathway

“…For example, bacteria isolates from rhizosphere soil of Brassica campestris were screened against Xcc , and two isolates are effective in black rot management ( Mishra and Arora, 2012 ). Recently, a Burkholderia anthina strain HN-8 exhibiting superb degradation activity of diffusible signal factor (DSF) can significantly reduce the severity of black rot disease in radishes and Chinese cabbage ( Ye et al., 2020 ). However, microbial antagonists that control crucifer black rot disease are rarely, and mechanisms of action urgently need to be uncovered.…”