Xanthomonas campestriscell–cell signalling molecule DSF (diffusible signal factor) elicits innate immunity in plants and is suppressed by the exopolysaccharide xanthan

Abstract

HighlightThe Xanthomonas conserved cell–cell quorum-sensing molecule elicits innate immunity in plants. The defence response provoked by DSF is suppressed by the exopolysaccharide xanthan, a quorum-sensing-regulated virulence factor.

Diffusible signal factor-dependent quorum sensing in pathogenic bacteria and its exploitation for disease control

“…DSF (but not the trans derivative of DSF) has been shown to trigger callose deposition, the induction of the PR1 gene and plant cell death in leaves of Arabidopsis and Nicotiana benthamiana and roots of rice (Kakkar et al . ). Treatment with DSF leads to a decrease in Xcc virulence and disease severity.…”

“…Recent work suggests that DSF per se may activate plant defence responses that could lead to impaired bacterial growth and virulence gene expression. DSF (but not the trans derivative of DSF) has been shown to trigger callose deposition, the induction of the PR1 gene and plant cell death in leaves of Arabidopsis and Nicotiana benthamiana and roots of rice (Kakkar et al 2015). Treatment with DSF leads to a decrease in Xcc virulence and disease severity.…”

“…Cis-2-decenoic acid induces biofilm dispersal in a range of Gram-negative and Grampositive bacteria that do not produce DSF family signals (reviewed by Marques et al 2015), and also improves the efficacy of antibiotic action in a number of organisms (see below). BDSF can modulate the yeast-hyphal transition in the dimorphic fungus Candida albicans responds to (Boon et al 2008) and DSF has been shown to induce defence-related responses in plants (Kakkar et al 2015).…”

Advances in the rhizosphere: stretching the interface of life

“…Quorum-sensing is involved in the regulation of several bacterial processes, such as biofilm formation, virulence in pathogenic bacteria, production of antimicrobial compounds by biocontrol plant growthpromoting rhizobacteria (PGPR) (Boyer and Wisniewski-Dyé 2009;Hartmann and Schikora 2012). Direct effects of bacterial quorum-sensing signals on plants also exist (Ortíz-Castro et al 2009;Kakkar et al 2015). When present at low concentrations, some antibiotics can also be involved in communication between microbial populations, triggering gene expression regulation in the exposed bacterial cells (Combes-Meynet et al 2011).…”

Draft Genome Sequence of the Xanthan Producer Xanthomonas campestris LMG 8031

“…The plant pathogenicity of xanthomonads is mainly based on exopolysaccharide production, which supports adhesion to enable plant penetration, as well as preservation against environmental stress factors such as desiccation or plant protection compounds (1–5). Next to its natural function, xanthan as a highly viscous exopolysaccharide obtained industrial relevance due to its excellent rheological behavior (6, 7).…”