scholarly journals Plant Cells under Attack: Unconventional Endomembrane Trafficking during Plant Defense

Plants ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 389 ◽  
Author(s):  
Guillermo Ruano ◽  
David Scheuring
Keyword(s):  
Immune Responses ◽  
Plant Defense ◽  
Vesicle Trafficking ◽  
Plant Cells ◽  
Plant Responses ◽  
Oxygen Species ◽  
Endomembrane System ◽  
Antimicrobial Proteins ◽  
Pathogen Attack ◽  
Endomembrane Trafficking

Since plants lack specialized immune cells, each cell has to defend itself independently against a plethora of different pathogens. Therefore, successful plant defense strongly relies on precise and efficient regulation of intracellular processes in every single cell. Smooth trafficking within the plant endomembrane is a prerequisite for a diverse set of immune responses. Pathogen recognition, signaling into the nucleus, cell wall enforcement, secretion of antimicrobial proteins and compounds, as well as generation of reactive oxygen species, all heavily depend on vesicle transport. In contrast, pathogens have developed a variety of different means to manipulate vesicle trafficking to prevent detection or to inhibit specific plant responses. Intriguingly, the plant endomembrane system exhibits remarkable plasticity upon pathogen attack. Unconventional trafficking pathways such as the formation of endoplasmic reticulum (ER) bodies or fusion of the vacuole with the plasma membrane are initiated and enforced as the counteraction. Here, we review the recent findings on unconventional and defense-induced trafficking pathways as the plant´s measures in response to pathogen attack. In addition, we describe the endomembrane system manipulations by different pathogens, with a focus on tethering and fusion events during vesicle trafficking.

scholarly journals An efficient direct screening system for microorganisms that activate plant immune responses based on plant–microbe interactions using cultured plant cells

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mari Kurokawa ◽  
Masataka Nakano ◽  
Nobutaka Kitahata ◽  
Kazuyuki Kuchitsu ◽  
Toshiki Furuya
Keyword(s):  
Immune Responses ◽  
Plant Defense ◽  
Pseudomonas Syringae ◽  
Large Scale ◽  
Plant Cells ◽  
Defense Responses ◽  
Root Tip ◽  
General Strategy ◽  
Plant Defense Responses ◽  
Microbe Interactions

AbstractMicroorganisms that activate plant immune responses have attracted considerable attention as potential biocontrol agents in agriculture because they could reduce agrochemical use. However, conventional methods to screen for such microorganisms using whole plants and pathogens are generally laborious and time consuming. Here, we describe a general strategy using cultured plant cells to identify microorganisms that activate plant defense responses based on plant–microbe interactions. Microbial cells were incubated with tobacco BY-2 cells, followed by treatment with cryptogein, a proteinaceous elicitor of tobacco immune responses secreted by an oomycete. Cryptogein-induced production of reactive oxygen species (ROS) in BY-2 cells served as a marker to evaluate the potential of microorganisms to activate plant defense responses. Twenty-nine bacterial strains isolated from the interior of Brassica rapa var. perviridis plants were screened, and 8 strains that enhanced cryptogein-induced ROS production in BY-2 cells were selected. Following application of these strains to the root tip of Arabidopsis seedlings, two strains, Delftia sp. BR1R-2 and Arthrobacter sp. BR2S-6, were found to induce whole-plant resistance to bacterial pathogens (Pseudomonas syringae pv. tomato DC3000 and Pectobacterium carotovora subsp. carotovora NBRC 14082). Pathogen-induced expression of plant defense-related genes (PR-1, PR-5, and PDF1.2) was enhanced by the pretreatment with strain BR1R-2. This cell–cell interaction-based platform is readily applicable to large-scale screening for microorganisms that enhance plant defense responses under various environmental conditions.

scholarly journals New insights into plant salt acclimation: the roles of vesicle trafficking and reactive oxygen species signalling in mitochondria and the endomembrane system

2014 ◽  
Vol 205 (1) ◽  
pp. 216-239 ◽  
Author(s):  
Jesus Garcia de la Garma ◽  
Nieves Fernandez-Garcia ◽  
Enas Bardisi ◽  
Beatriz Pallol ◽  
Jose Salvador Asensio-Rubio ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Vesicle Trafficking ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Endomembrane System ◽  
Salt Acclimation

scholarly journals Reactive oxygen species signaling and stomatal movement in plant responses to drought stress and pathogen attack

2018 ◽  
Vol 60 (9) ◽  
pp. 805-826 ◽  
Author(s):  
Junsheng Qi ◽  
Chun-Peng Song ◽  
Baoshan Wang ◽  
Jianmin Zhou ◽  
Jaakko Kangasjärvi ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Drought Stress ◽  
Reactive Oxygen ◽  
Plant Responses ◽  
Stomatal Movement ◽  
Oxygen Species ◽  
Pathogen Attack ◽  
Reactive Oxygen Species Signaling

scholarly journals An Immuno-Suppressive Aphid Saliva Protein Is Delivered into the Cytosol of Plant Mesophyll Cells During Feeding

2016 ◽  
Vol 29 (11) ◽  
pp. 854-861 ◽  
Author(s):  
Sam T. Mugford ◽  
Elaine Barclay ◽  
Claire Drurey ◽  
Kim C. Findlay ◽  
Saskia A. Hogenhout
Keyword(s):  
Plant Defense ◽  
Plant Cells ◽  
Defense Responses ◽  
Plant Responses ◽  
Plant Defense Responses ◽  
Mesophyll Cells ◽  
Virulence Proteins ◽  
Feeding Sites ◽  
Ultrathin Sections ◽  
Aphid Feeding

Herbivore selection of plant hosts and plant responses to insect colonization have been subjects of intense investigations. A growing body of evidence suggests that, for successful colonization to occur, (effector/virulence) proteins in insect saliva must modulate plant defense responses to the benefit of the insect. A range of insect saliva proteins that modulate plant defense responses have been identified, but there is no direct evidence that these proteins are delivered into specific plant tissues and enter plant cells. Aphids and other sap-sucking insects of the order Hemiptera use their specialized mouthparts (stylets) to probe plant mesophyll cells until they reach the phloem cells for long-term feeding. Here, we show, by immunogold-labeling of ultrathin sections of aphid feeding sites, that an immuno-suppressive aphid effector localizes in the cytoplasm of mesophyll cells near aphid stylets but not in cells further away from aphid feeding sites. In contrast, another aphid effector protein localizes in the sheaths composed of gelling saliva that surround the aphid stylets. Thus, insects deliver effectors directly into plant tissue. Moreover, different aphid effectors locate extracellularly in the sheath saliva or are introduced into the cytoplasm of plant cells. [Formula: see text] Copyright © 2016 The Author(s). This is an open-access article distributed under the CC BY-NC-ND 4.0 International license .

scholarly journals An immuno-suppressive aphid saliva protein is delivered into the cytosol of plant mesophyll cells during feeding

2016 ◽  
Author(s):  
Sam T. Mugford ◽  
Elaine Barclay ◽  
Claire Drurey ◽  
Kim C. Findlay ◽  
Saskia A. Hogenhout
Keyword(s):  
Plant Defense ◽  
Plant Cells ◽  
Defense Responses ◽  
Plant Responses ◽  
Plant Defense Responses ◽  
Mesophyll Cells ◽  
Virulence Proteins ◽  
Feeding Sites ◽  
Ultrathin Sections ◽  
Aphid Feeding

AbstractHerbivore selection of plant hosts and plant responses to insect colonization have been subjects of intense investigations. A growing body of evidence suggests that for successful colonization to occur, (effector/virulence) proteins in insect saliva must modulate plant defense responses to the benefit of the insect. A range of insect saliva proteins that modulate plant defense responses have been identified, but there is no direct evidence that these proteins are delivered into specific plant tissues and enter plant cells. Aphids and other sap-sucking insects of the order Hemiptera use their specialized mouthparts (stylets) to probe plant mesophyll cells, until they reach the phloem cells for long-term feeding. Here we show by immunogold-labeling of ultrathin sections of aphid feeding sites that an immuno-suppressive aphid effector localizes in the cytoplasm of mesophyll cells near aphid stylets, but not in cells further away from aphid feeding sites. In contrast, another aphid effector protein localizes in the sheaths composed of gelling saliva that surround the aphid stylets. Thus, insects deliver effectors directly into plant tissue. Moreover, different aphid effectors locate extracellularly in the sheath saliva or are introduced into the cytoplasm of plant cells.

Elicitor Recognition and Signal Transduction in Plant Defense Gene Activation

1990 ◽  
Vol 45 (6) ◽  
pp. 569-575 ◽  
Author(s):  
Dierk Scheel ◽  
Jane E. Parker
Keyword(s):  
Signal Transduction ◽  
Plant Defense ◽  
Transcriptional Activation ◽  
Molecular Mechanisms ◽  
Plant Protection ◽  
Plant Cells ◽  
Defense Responses ◽  
Plant Defense Responses ◽  
Defense Genes ◽  
Plant Defense Genes

Abstract Plants defend themselves against pathogen attack by activating a whole set of defense responses, most of them relying on transcriptional activation of plant defense genes. The same responses are induced by treatment of plant cells with elicitors released from the pathogen or from the plant surface. Several plant/elicitor combinations have been used successfully as experimental systems to investigate the molecular basis of plant defense responses. Receptor-like structures on the plasma membrane of plant cells appear to bind the elicitors. Thereby, intracellular signal transduction chains are initiated which finally result in the activation of plant defense genes. A better understanding of the molecular mechanisms of early processes in plant defense responses, as provided by these studies, may in the long term help to develop environmentally safe plant protection methods for agriculture.

scholarly journals Integrative Proteomic and Phosphoproteomic Analyses of Pattern- and Effector-Triggered Immunity in Tomato

2021 ◽  
Vol 12 ◽  
Author(s):  
Juanjuan Yu ◽  
Juan M. Gonzalez ◽  
Zhiping Dong ◽  
Qianru Shan ◽  
Bowen Tan ◽  
...  
Keyword(s):  
Plant Defense ◽  
Pseudomonas Syringae ◽  
Redox Homeostasis ◽  
Mitogen Activated Protein Kinase ◽  
Regulatory Mechanisms ◽  
Pcr Analysis ◽  
Plant Responses ◽  
Serine Esterase ◽  
Proteomics Data ◽  
Effector Triggered Immunity

Plants have evolved a two-layered immune system consisting of pattern-triggered immunity (PTI) and effector-triggered immunity (ETI). PTI and ETI are functionally linked, but also have distinct characteristics. Unraveling how these immune systems coordinate plant responses against pathogens is crucial for understanding the regulatory mechanisms underlying plant defense. Here we report integrative proteomic and phosphoproteomic analyses of the tomato-Pseudomonas syringae (Pst) pathosystem with different Pst mutants that allow the dissection of PTI and ETI. A total of 225 proteins and 79 phosphopeptides differentially accumulated in tomato leaves during Pst infection. The abundances of many proteins and phosphoproteins changed during PTI or ETI, and some responses were triggered by both PTI and ETI. For most proteins, the ETI response was more robust than the PTI response. The patterns of protein abundance and phosphorylation changes revealed key regulators involved in Ca2+ signaling, mitogen-activated protein kinase cascades, reversible protein phosphorylation, reactive oxygen species (ROS) and redox homeostasis, transcription and protein turnover, transport and trafficking, cell wall remodeling, hormone biosynthesis and signaling, suggesting their common or specific roles in PTI and/or ETI. A NAC (NAM, ATAF, and CUC family) domain protein and lipid particle serine esterase, two PTI-specific genes identified from previous transcriptomic work, were not detected as differentially regulated at the protein level and were not induced by PTI. Based on integrative transcriptomics and proteomics data, as well as qRT-PCR analysis, several potential PTI and ETI-specific markers are proposed. These results provide insights into the regulatory mechanisms underlying PTI and ETI in the tomato-Pst pathosystem, and will promote future validation and application of the disease biomarkers in plant defense.

An Emerging Role for Chloroplasts in Disease and Defense

2021 ◽  
Vol 59 (1) ◽  
pp. 423-445
Author(s):  
Pradeep Kachroo ◽  
Tessa M. Burch-Smith ◽  
Murray Grant
Keyword(s):  
Immune Responses ◽  
De Novo ◽  
Current Knowledge ◽  
Reactive Oxygen ◽  
Host Immunity ◽  
Retrograde Signaling ◽  
Oxygen Species ◽  
Nitrogen Species ◽  
De Novo Synthesis ◽  
Key Players

Chloroplasts are key players in plant immune signaling, contributing to not only de novo synthesis of defensive phytohormones but also the generation of reactive oxygen and nitrogen species following activation of pattern recognition receptors or resistance (R) proteins. The local hypersensitive response (HR) elicited by R proteins is underpinned by chloroplast-generated reactive oxygen species. HR-induced lipid peroxidation generates important chloroplast-derived signaling lipids essential to the establishment of systemic immunity. As a consequence of this pivotal role in immunity, pathogens deploy effector complements that directly or indirectly target chloroplasts to attenuate chloroplast immunity (CI). Our review summarizes the current knowledge of CI signaling and highlights common pathogen chloroplast targets and virulence strategies. We address emerging insights into chloroplast retrograde signaling in immune responses and gaps in our knowledge, including the importance of understanding chloroplast heterogeneity and chloroplast involvement in intraorganellular interactions in host immunity.

scholarly journals Nitric Oxide Enhances Cytotoxicity of Lead by Modulating the Generation of Reactive Oxygen Species and Is Involved in the Regulation of Pb2+ and Ca2+ Fluxes in Tobacco BY-2 Cells

Plants ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 403 ◽  
Author(s):  
Jiaye Wu ◽  
Yue Zhang ◽  
Ruizhi Hao ◽  
Yuan Cao ◽  
Xiaoyi Shan ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Reactive Oxygen Species ◽  
Heavy Metal ◽  
Cell Death ◽  
Calcium Homeostasis ◽  
Reactive Oxygen ◽  
Ros Generation ◽  
Plant Responses ◽  
Oxygen Species ◽  
In Cells

Lead is a heavy metal known to be toxic to both animals and plants. Nitric oxide (NO) was reported to participate in plant responses to different heavy metal stresses. In this study, we analyzed the function of exogenous and endogenous NO in Pb-induced toxicity in tobacco BY-2 cells, focusing on the role of NO in the generation of reactive oxygen species (ROS) as well as Pb2+ and Ca2+ fluxes using non-invasive micro-test technology (NMT). Pb treatment induced BY-2 cell death and rapid NO and ROS generation, while NO burst occurred earlier than ROS accumulation. The elimination of NO by 2-4-carboxyphenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO) resulted in a decrease of ROS, and the supplementation of NO by sodium nitroprusside (SNP) caused an increased accumulation of ROS. Furthermore, the addition of exogenous NO stimulated Pb2+ influx, thus promoting Pb uptake in cells and aggravating Pb-induced toxicity in cells, whereas the removal of endogenous NO produced the opposite effect. Moreover, we also found that both exogenous and endogenous NO enhanced Pb-induced Ca2+ effluxes and calcium homeostasis disorder. These results suggest that exogenous and endogenous NO played a critical regulatory role in BY-2 cell death induced by Pb stress by promoting Pb2+ influx and accumulation and disturbing calcium homeostasis.

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