scholarly journals Deciphering the mode of action and host recognition of bacterial type III effectors

2010 ◽  
Vol 37 (10) ◽  
pp. 926 ◽  
Author(s):  
Selena Gimenez-Ibanez ◽  
Dagmar R. Hann ◽  
John P. Rathjen
Keyword(s):  
Mode Of Action ◽  
Pathogenic Bacteria ◽  
Plant Immunity ◽  
Plant Defence ◽  
Host Recognition ◽  
Type Iii Effectors ◽  
Host Cytoplasm ◽  
Host Plasma Membrane ◽  
Defence Responses ◽  
Bacterial Effectors

Plant pathogenic bacteria adhere to cell walls and remain external to the cell throughout the pathogenic lifecycle, where they elicit host immunity through host plasma membrane localised receptors. To be successful pathogens, bacteria must suppress these defence responses, which they do by secreting a suite of virulence effector molecules into the host cytoplasm. However, effectors themselves can act as elicitors after perception by intracellular host immune receptors, thus, re-activating plant immunity. Bacterial effectors generally target host molecules through specific molecular activities to defeat plant defence responses. Although effectors can be used as tools to elucidate components of plant immunity, only a handful of these molecular targets are known and much remains to be learnt about effector strategies for bacterial pathogenicity. This review highlights recent advances in our understanding of the mode of action of bacterial effectors, which in the future will lead to improvements in agriculture.

Salicylic acid signalling: new insights and prospects at a quarter-century milestone

2015 ◽  
Vol 58 ◽  
pp. 101-113 ◽  
Author(s):  
Xiaoyu Liu ◽  
Kristin S. Rockett ◽  
Camilla J. Kørner ◽  
Karolina M. Pajerowska-Mukhtar
Keyword(s):  
Salicylic Acid ◽  
Molecular Mechanisms ◽  
Plant Immunity ◽  
Plant Defence ◽  
Immune Memory ◽  
Quarter Century ◽  
Modern Agriculture ◽  
Signalling Network ◽  
Defence Responses ◽  
Plant Defence Responses

The plant hormone salicylic acid (SA) plays an essential role in the regulation of diverse biological processes throughout the entire lifespan of the plant. Twenty-five years ago, SA first emerged as an endogenous signal capable of inducing plant defence responses both at the site of infection and in the systemic tissue of the plant. Since then, SA-mediated signalling pathways have been extensively characterized and dissected using genetic and biochemical approaches. Current research is largely focused on the identification of novel SA downstream signalling genes, in order to understand their precise contributions to the phytohormonal cross-talk and signalling network. This will subsequently help us to identify novel targets that are important for plant health, and contribute to advances in modern agriculture. In this chapter we highlight recent advances in the field of SA biosynthesis and the discovery of candidates for systemic mobile signals. We also discuss the molecular mechanisms underlying SA perception. In addition, we review the novel SA signalling components that expand the scope of SA functions beyond plant immunity to include plant growth and development, endoplasmic reticulum (ER) stress, DNA repair and homologous recombination. Finally, we shed light on the roles of SA in epigenetically controlled transgenerational immune memory that has long-term benefits for plants.

scholarly journals PAMP-INDUCED SECRETED PEPTIDE 3 (PIP3) modulates immunity in Arabidopsis thaliana

2019 ◽  
Author(s):  
Javad Najafi ◽  
Tore Brembu ◽  
Ane Kjersti Vie ◽  
Rannveig Viste ◽  
Per Winge ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Plant Immunity ◽  
Plant Defence ◽  
Fine Tuning ◽  
Callose Deposition ◽  
Modified Peptides ◽  
Defence Responses ◽  
Plant Defence Responses ◽  
Increased Susceptibility

Abstract Small post-translationally modified peptides are important signalling components of plant defence responses against phytopathogens, acting both as positive and negative modulators. PAMP-INDUCED SECRETED PEPTIDE (PIP) 1 and 2 has been shown to amplify plant immunity. Here we investigate the role of the related peptide PIP3 in the regulation of immune response in Arabidopsis. Treatment with synthetic PIP peptides led to similar transcriptome reprogramming, indicating an effect on innate immunity-related processes and phytohormones, including jasmonic acid (JA) biosynthesis and signalling. PIP3 overexpressing (OX) plants showed enhanced growth inhibition in response to flg22 exposure. In addition, flg22-induced production of reactive oxygen species and callose deposition were significantly reduced in PIP3-OX plants. Interestingly, PIP3-OX plants showed increased susceptibility both toward Botrytis cinerea and the biotrophic pathogen Pseudomonas syringae. Expression of both JA and salicylic acid biosynthesis and signalling genes was more induced during B. cinerea infection in PIP3-OX plants compared with wild-type plants. Promoter and ChIP-seq analyses indicated that the transcription factors WRKY18, WRKY33 and WRKY40 cooperatively act as repressors for PIP3. The results point to a fine-tuning role for PIP3 in modulation of immunity through the regulation of SA and JA biosynthesis and signalling pathways in Arabidopsis.

scholarly journals Prospects of Gene Knockouts in the Functional Study of MAMP-Triggered Immunity: A Review

2020 ◽  
Vol 21 (7) ◽  
pp. 2540 ◽  
Author(s):  
Benedict C. Offor ◽  
Ian A. Dubery ◽  
Lizelle A. Piater
Keyword(s):  
Insertional Mutagenesis ◽  
Molecular Mechanisms ◽  
Plant Immunity ◽  
Plant Defence ◽  
In Vivo Studies ◽  
Functional Study ◽  
Membrane Raft ◽  
Receptor Complexes ◽  
Defence Responses

Plants depend on both preformed and inducible defence responses to defend themselves against biotic stresses stemming from pathogen attacks. In this regard, plants perceive pathogenic threats from the environment through pattern recognition receptors (PRRs) that recognise microbe-associated molecular patterns (MAMPs), and so induce plant defence responses against invading pathogens. Close to thirty PRR proteins have been identified in plants, however, the molecular mechanisms underlying MAMP perception by these receptors/receptor complexes are not fully understood. As such, knockout (KO) of genes that code for PRRs and co-receptors/defence-associated proteins is a valuable tool to study plant immunity. The loss of gene activity often causes changes in the phenotype of the model plant, allowing in vivo studies of gene function and associated biological mechanisms. Here, we review the functions of selected PRRs, brassinosteroid insensitive 1 (BRI1) associated receptor kinase 1 (BAK1) and other associated defence proteins that have been identified in plants, and also outline KO lines generated by T-DNA insertional mutagenesis as well as the effect on MAMP perception—and triggered immunity (MTI). In addition, we further review the role of membrane raft domains in flg22-induced MTI in Arabidopsis, due to the vital role in the activation of several proteins that are part of the membrane raft domain theory in this regard.

scholarly journals RNA-Binding Proteins in Plant Immunity

2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
Virginia Woloshen ◽  
Shuai Huang ◽  
Xin Li
Keyword(s):  
Immune Responses ◽  
Rna Processing ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Plant Immunity ◽  
Plant Defence ◽  
Depth Analysis ◽  
Defence Responses ◽  
High Degree

Plant defence responses against pathogen infection are crucial to plant survival. The high degree of regulation of plant immunity occurs both transcriptionally and posttranscriptionally. Once transcribed, target gene RNA must be processed prior to translation. This includes polyadenylation,5′capping, editing, splicing, and mRNA export. RNA-binding proteins (RBPs) have been implicated at each level of RNA processing. Previous research has primarily focused on structural RNA-binding proteins of yeast and mammals; however, more recent work has characterized a number of plant RBPs and revealed their roles in plant immune responses. This paper provides an update on the known functions of RBPs in plant immune response regulation. Future in-depth analysis of RBPs and other related players will unveil the sophisticated regulatory mechanisms of RNA processing during plant immune responses.

Microbial elicitors of plant defence responses activate transcription of a retrotransposon

1994 ◽  
Vol 5 (4) ◽  
pp. 535-542 ◽  
Author(s):  
Sylvie Pouteau ◽  
Marie-Angele Grandbastien ◽  
Martine Boccara
Keyword(s):  
Plant Defence ◽  
Defence Responses ◽  
Plant Defence Responses

scholarly journals Assessing the Molecular Targets and Mode of Action of Furanone C-30 on Pseudomonas aeruginosa Quorum Sensing

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1620
Author(s):  
Victor Markus ◽  
Karina Golberg ◽  
Kerem Teralı ◽  
Nazmi Ozer ◽  
Esti Kramarsky-Winter ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Quorum Sensing ◽  
Conformational Changes ◽  
Mode Of Action ◽  
Pathogenic Bacteria ◽  
Molecular Targets ◽  
Resistant Bacteria ◽  
Public Healthcare ◽  
C 30

Quorum sensing (QS), a sophisticated system of bacterial communication that depends on population density, is employed by many pathogenic bacteria to regulate virulence. In view of the current reality of antibiotic resistance, it is expected that interfering with QS can address bacterial pathogenicity without stimulating the incidence of resistance. Thus, harnessing QS inhibitors has been considered a promising approach to overriding bacterial infections and combating antibiotic resistance that has become a major threat to public healthcare around the globe. Pseudomonas aeruginosa is one of the most frequent multidrug-resistant bacteria that utilize QS to control virulence. Many natural compounds, including furanones, have demonstrated strong inhibitory effects on several pathogens via blocking or attenuating QS. While the natural furanones show no activity against P. aeruginosa, furanone C-30, a brominated derivative of natural furanone compounds, has been reported to be a potent inhibitor of the QS system of the notorious opportunistic pathogen. In the present study, we assess the molecular targets and mode of action of furanone C-30 on P. aeruginosa QS system. Our results suggest that furanone C-30 binds to LasR at the ligand-binding site but fails to establish interactions with the residues crucial for the protein’s productive conformational changes and folding, thus rendering the protein dysfunctional. We also show that furanone C-30 inhibits RhlR, independent of LasR, suggesting a complex mechanism for the agent beyond what is known to date.

scholarly journals Activation of Local and Systemic Defence Responses by Flg22 Is Dependent on Daytime and Ethylene in Intact Tomato Plants

2021 ◽  
Vol 22 (15) ◽  
pp. 8354
Author(s):  
Zalán Czékus ◽  
András Kukri ◽  
Kamirán Áron Hamow ◽  
Gabriella Szalai ◽  
Irma Tari ◽  
...  
Keyword(s):  
Stomatal Closure ◽  
Plant Defence ◽  
Time Of Day ◽  
Light Period ◽  
Ethylene Response Factor ◽  
Wild Type ◽  
Tomato Plants ◽  
Production Of Hydrogen ◽  
Pathogenesis Related ◽  
Defence Responses

The first line of plant defence responses against pathogens can be induced by the bacterial flg22 and can be dependent on various external and internal factors. Here, we firstly studied the effects of daytime and ethylene (ET) using Never ripe (Nr) mutants in the local and systemic defence responses of intact tomato plants after flg22 treatments. Flg22 was applied in the afternoon and at night and rapid reactions were detected. The production of hydrogen peroxide and nitric oxide was induced by flg22 locally, while superoxide was induced systemically, in wild type plants in the light period, but all remained lower at night and in Nr leaves. Flg22 elevated, locally, the ET, jasmonic acid (JA) and salicylic acid (SA) levels in the light period; these levels did not change significantly at night. Expression of Pathogenesis-related 1 (PR1), Ethylene response factor 1 (ERF1) and Defensin (DEF) showed also daytime- and ET-dependent changes. Enhanced ERF1 and DEF expression and stomatal closure were also observable in systemic leaves of wild type plants in the light. These data demonstrate that early biotic signalling in flg22-treated leaves and distal ones is an ET-dependent process and it is also determined by the time of day and inhibited in the early night phase.

scholarly journals Zinc phosphate protects tomato plants against Pseudomonas syringae pv. tomato

2021 ◽  
Author(s):  
Mara Quaglia ◽  
Marika Bocchini ◽  
Benedetta Orfei ◽  
Roberto D’Amato ◽  
Franco Famiani ◽  
...  
Keyword(s):  
Disease Severity ◽  
Pseudomonas Syringae ◽  
Zinc Phosphate ◽  
Plant Defence ◽  
In Planta ◽  
Tomato Plants ◽  
Pathogenesis Related Protein ◽  
Defence Responses ◽  
Plant Defence Responses

AbstractThe purpose of this study was to determine whether zinc phosphate treatments of tomato plants (Solanum lycopersicum L.) can attenuate bacterial speck disease severity through reduction of Pseudomonas syringae pv. tomato (Pst) growth in planta and induce morphological and biochemical plant defence responses. Tomato plants were treated with 10 ppm (25.90 µM) zinc phosphate and then spray inoculated with strain DAPP-PG 215, race 0 of Pst. Disease symptoms were recorded as chlorosis and/or necrosis per leaf (%) and as numbers of necrotic spots. Soil treatments with zinc phosphate protected susceptible tomato plants against Pst, with reductions in both disease severity and pathogen growth in planta. The reduction of Pst growth in planta combined with significantly higher zinc levels in zinc-phosphate-treated plants indicated direct antimicrobial toxicity of this microelement, as also confirmed by in vitro assays. Morphological (i.e. callose apposition) and biochemical (i.e., expression of salicylic-acid-dependent pathogenesis-related protein PR1b1 gene) defence responses were induced by the zinc phosphate treatment, as demonstrated by histochemical and qPCR analyses, respectively. In conclusion, soil treatments with zinc phosphate can protect tomato plants against Pst attacks through direct antimicrobial activity and induction of morphological and biochemical plant defence responses.

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