Abstract
Quorum sensing (QS) is a cell–cell communication mechanism among bacterial populations that is regulated through gene expression in response to cell density. The pathogenicity of Xanthomonas campestris pv. campestris (Xcc) is modulated by the diffusible signal factor (DSF)-mediated QS system. DSF is widely conserved in a variety of gram-negative bacterial pathogens. In this study, DSF-degrading bacteria and their enzymes were thoroughly explored as a biocontrol agent against Xcc. The results indicated that a novel DSF-degrading bacterium, Acinetobacter lactucae QL-1, effectively attenuated Xcc virulence through quorum quenching. Lab-based experiments indicated that plants inoculated with QL-1 and Xcc had less tissue decay than those inoculated with Xcc alone. Co-inoculation of strains Xcc and QL-1 significantly reduced the incidence and severity of disease in plants. Similarly, the application of crude enzymes of strain QL-1 substantially reduced the disease severity caused by Xcc. The results showed that strain QL-1 and its enzymes possess promising potential, which could be further investigated to better protect plants from DSF-dependent pathogens.
Highlights
Cruciferous vegetables are of global economic importance and include a wide range of unique members such as Bok Choy, cabbage, and broccoli (Rakow, 2004; Somec and Sondi, 2019)
Bacterial strains from various soil samples were enriched in minimal salt medium (MSM) containing 50 μmol L−1 of diffusible signal factor (DSF) as the sole carbon source
According to the results of soil enrichment culture, several morphologically different bacterial strains producing clear zones on MSM plates supplemented with DSF were isolated from various soils
Summary
Cruciferous vegetables are of global economic importance and include a wide range of unique members such as Bok Choy, cabbage, and broccoli (Rakow, 2004; Somec and Sondi, 2019). Campestris (Xcc) becomes severely destructive under warm and humid conditions (Gupta et al, 2013). This leads to serious economic losses by reducing the shelf life and market value of infected crop plants (Massomo, 2002; Massomo et al, 2004). To overcome the effects of black rot, chemical control (Mew and Natural, 1993; Mishra and Arora, 2012; Vicente and Holub, 2013), cultivation of certified disease-free transplants and seeds, cultivation of resistant cultivars, hot water treatment (Nega et al, 2003), and drip irrigation are Efficacy of A. lactucae QL-1 in DSF Degradation generally recommended (Luiz et al, 2016). QQ disrupts quorum sensing (QS) either by the degradation of QS signals or interference with signal generation or perception (He and Zhang, 2008)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
