Lipopolysaccharide mobility in leaf tissue of Arabidopsis thaliana

Abstract

Bacterial lipopolysaccharides (LPS) are triggers of defence responses in plants, and induce local as well as systemic acquired resistance. Arabidopsis thaliana plants pretreated with LPS show an increased resistance to the virulent bacterial plant pathogen Pseudomonas syringae pv. tomato DC3000. To investigate the mobilization and transport of LPS in Arabidopsis leaves, fluorescently labelled LPS (Alexa Fluor® 488 conjugate) from Salmonella minnesota was used. Leaves were pressure infiltrated with fluorescein-labelled LPS and fluorescence microscopy was used to follow the movement and localization of LPS as a function of time. The observation of leaves 1 h after supplementation with fluorescein-labelled LPS revealed a fluorescent signal in the intercellular space. Capillary zone electrophoresis was used for the detection and analysis of the labelled LPS in directly treated leaves and systemic leaves. In addition, gel electrophoresis was used to confirm LPS mobilization. The results indicated that LPS mobilization/translocation occurs through the xylem from local, treated leaves to systemic, untreated leaves. Consequently, care should be taken when ascribing the observed biochemical responses and induced resistance from LPS perception as being uniquely local or systemic, as these responses might overlap because of the mobility of LPS in the plant vascular system.

Flagellin peptide flg22 gains access to long-distance trafficking in Arabidopsis via its receptor, FLS2

“…It was speculated that LPS, which was detected in distal tissues after a local application, might directly contribute to SAR (Zeidler et al , 2010), although further studies are needed to establish if flg22 or LPS directly induces defenses in distal tissues. Mobile elicitins directly induce necrosis in distal tissues (Ricci et al , 1989; Uhlíková et al , 2016).…”

“…Application of other PAMPs such as lipopolysaccharide (LPS), chitosan or elicitins to the lower leaves of a plant also activates SAR (Ricci et al , 1989; Mishina and Zeier, 2007; Faoro et al , 2008; Zeidler et al , 2010). It is assumed that secondary plant-derived mobile signals generated during the immune response to elicitors are responsible for SAR.…”

Molecular characterisation and regulation of a Nicotiana tabacum S-domain receptor-like kinase gene induced during an early rapid response to lipopolysaccharides

“…Bi-phasic induction of defence-related genes was reported as part of the onset of SAR (Lamb and Dixon, 1997), indicative of two signalling events in response to increased levels of H 2 O 2 and SA (Shah, 2003). Similarly, perception of LPS from B. cepacia by tobacco cells triggers an oxidative burst and induces the synthesis of SA up to 8 h after LPS perception (Zeidler et al, 2010).…”

MAMP (microbe-associated molecular pattern) triggered immunity in plants

“…It was speculated that this endocytosis in tobacco cells was, in correlation with the mammalian system, part of a down regulation of defense responses. In a recent study by Zeidler et al (2010) localization and mobilization of fluorescein-labeled Salmonella minnesota LPS was studied in Arabidopsis . Leaves were pressure infiltrated with fluorescein-labeled S. minnesota LPS and the mobility of LPS was studied over time by fluorescence microscopy.…”