pectins and Disease-Resistance

Plants have evolved a repertoire of monitoring systems to sense plant morphogenesis and to face environmental changes and threats caused by different attackers. These systems integrate different signals into overreaching triggering pathways which coordinate developmental and defence-associated responses. The plant cell wall, a dynamic and complex structure surrounding every plant cell, has emerged recently as an essential component of plant monitoring systems, thus expanding its function as a passive defensive barrier. Plants have a dedicated mechanism for maintaining cell wall integrity (CWI) which comprises a diverse set of plasma membrane-resident sensors and pattern recognition receptors (PRRs). The PRRs perceive plant-derived ligands, such as peptides or wall glycans, known as damage-associated molecular patterns (DAMPs). These DAMPs function as 'danger' alert signals activating DAMP-triggered immunity (DTI), which shares signalling components and responses with the immune pathways triggered by non-self microbe-associated molecular patterns that mediate disease resistance. Alteration of CWI by impairment of the expression or activity of proteins involved in cell wall biosynthesis and/or remodelling, as occurs in some plant cell wall mutants, or by wall damage due to colonization by pathogens/pests, activates specific defensive and growth responses. Our current understanding of how these alterations of CWI are perceived by the wall monitoring systems is scarce and few plant sensors/PRRs and DAMPs have been characterized. The identification of these CWI sensors and PRR-DAMP pairs will help us to understand the immune functions of the wall monitoring system, and might allow the breeding of crop varieties and the design of agricultural strategies that would enhance crop disease resistance.

Topics: Cell Wall; Cellulose; Disease Resistance; Glucans; Host-Pathogen Interactions; Pathogen-Associated Molecular Pattern Molecules; Pectins; Plant Cells; Plant Diseases; Plant Immunity; Polysaccharides; Receptors, Pattern Recognition

The constitutional isomers and tautomers of oxadiazolones, as well as their mono- and disulfur analogues, were calculated at the B3LYP/aug-cc-pVDZ level. Four groups of 30 molecules each were considered: oxadiazolone, oxadiazolthione, thiadiazolone, and thiadiazolthione isomers. The compounds were categorized into six groups according to permutations of three heteroatoms in the five-membered ring. Additionally, each of the constitutional isomer was considered to have five tautomers conserving stable five-membered ring: two NH tautomers, two rotameric OH (or SH) forms and one CH. La trombocitosis es un hallazgo casual frecuente en pediatría. En niños, predominan las formas secundarias, siendo las infecciones su causa más prevalente. Se distinguen 4 grados de trombocitosis en función del número de plaquetas; en la forma extrema, se supera el 1.000.000/mm. Endoscopic thrombin injection was similar to glue injection in achieving successful hemostasis of AGVH. However, a higher incidence of complications may be associated with glue injection.

Topics: Acetaminophen; Administration, Oral; Adolescent; Adsorption; Adult; Allyl Compounds; Amylopectin; Amylose; Anaerobiosis; Animals; Anti-Bacterial Agents; Anura; Arginase; Arthritis, Rheumatoid; Asthma; Atmosphere; B-Lymphocytes; Basic Helix-Loop-Helix Transcription Factors; Bioelectric Energy Sources; Biofilms; Biofuels; Biomarkers; Biopolymers; Bioreactors; Brain; Brain Injuries, Traumatic; Breast Neoplasms; Calibration; Carbon Tetrachloride; Caspase 3; Catalysis; Catechin; Cations; Cattle; CD4-Positive T-Lymphocytes; CD8-Positive T-Lymphocytes; Cell Body; Cell Line, Tumor; Cell Plasticity; Chemical and Drug Induced Liver Injury; Chemistry Techniques, Synthetic; China; Chitosan; Chloride Channels; Chromatography, High Pressure Liquid; Chromosome Mapping; Cognition; Cognitive Dysfunction; Cohort Studies; Colitis, Ulcerative; Colloids; Coloring Agents; Congresses as Topic; Correlation of Data; Crystallization; Cyanoacrylates; Cyclohexane Monoterpenes; Cyprinidae; Cytochrome P-450 CYP1A1; Death, Sudden; Dent Disease; Dietary Supplements; Diffusion Magnetic Resonance Imaging; Disease Models, Animal; Disease Progression; Disease Resistance; Disulfides; Drug Monitoring; Drug Stability; Ecotoxicology; Electricity; Electrodes; Endocytosis; Environmental Exposure; Environmental Monitoring; Enzyme Inhibitors; Epithelial-Mesenchymal Transition; Esophageal and Gastric Varices; Esters; Fagopyrum; Female; Ferrosoferric Oxide; Flame Retardants; Flavobacteriaceae; Flow Cytometry; Follow-Up Studies; Formoterol Fumarate; Fusarium; Garlic; Gastrointestinal Hemorrhage; Gene Expression; Genes, Plant; Genetic Markers; Glial Fibrillary Acidic Protein; Gliosis; Global Health; Glutathione Transferase; Glycine max; Gum Arabic; Hemostasis, Endoscopic; Hepatocytes; Hippocampus; Humans; Hydrogen-Ion Concentration; Illinois; Immunoglobulin G; Indoleamine-Pyrrole 2,3,-Dioxygenase; Infant, Newborn; Infant, Small for Gestational Age; Injections, Intraperitoneal; Interleukin-4; Iowa; Iron; Ki-67 Antigen; Kidney; Kinetics; Kynurenine; Lakes; Levofloxacin; Lipid Peroxidation; Lipids; Liver; Liver Cirrhosis, Experimental; Magnetic Fields; Magnetic Iron Oxide Nanoparticles; Male; Manure; Maze Learning; Memory, Short-Term; Metal Nanoparticles; Metals, Heavy; Methane; Mice; Mice, Inbred C57BL; Mice, Knockout; Michigan; Microalgae; Microbial Consortia; Mitochondria; Models, Animal; Models, Chemical; Models, Neurological; Molecular Structure; Molecular Weight; Mutation; Myeloid-Derived Suppressor Cells; NADPH Oxidase 2; Neoplasm Recurrence, Local; Neurites; Neurons; Neuroprotective Agents; NF-kappa B; NIH 3T3 Cells; Nitric Oxide Synthase Type II; Nitrogen; Ohio; Ointments; Ontario; Organelle Biogenesis; Organophosphates; Organophosphorus Compounds; Oxidative Stress; Palladium; Particle Size; Pectins; Phenotype; Phytotherapy; Piperidines; Placenta; Plant Diseases; Plant Extracts; Polymers; Polymorphism, Genetic; Polyphenols; Powders; Pregnancy; Pregnancy Trimester, First; Prospective Studies; Protein Kinase Inhibitors; Protein Structure, Secondary; Proteins; Pyridines; Pyrimidines; Rats, Wistar; Real-Time Polymerase Chain Reaction; Receptors, Aryl Hydrocarbon; Receptors, Chemokine; Receptors, Formyl Peptide; Receptors, Lipoxin; Recovery of Function; Recurrence; Reference Standards; Reference Values; Reproducibility of Results; Respiratory Function Tests; Retrospective Studies; Risk; Sensitivity and Specificity; Sewage; Signal Transduction; Sodium Glutamate; Soil; Solanum tuberosum; Solubility; Solutions; Spectroscopy, Fourier Transform Infrared; Spectrum Analysis; Spermatozoa; STAT3 Transcription Factor; Sulfamethoxazole; Tea; Temperature; Thermodynamics; Thrombin; Treatment Outcome; Triazoles; United States; Viscosity; Waste Disposal, Fluid; Wastewater; Water; Water Pollutants, Chemical; Water Purification; White Matter; Wisconsin; X-Ray Diffraction; Zea mays

The cell wall is a complex structure mainly composed by a cellulose-hemicellulose network embedded in a cohesive pectin matrix. Pectin is synthesized in a highly methyl esterified form and is de-esterified in muro by pectin methyl esterases (PMEs). The degree and pattern of methyl esterification affect the cell wall structure and properties with consequences on both the physiological processes of the plants and their resistance to pathogens. PME activity displays a crucial role in the outcome of the plant-pathogen interactions by making pectin more susceptible to the action of the enzymes produced by the pathogens. This review focuses on the impact of pectin methyl esterification in plant-pathogen interactions and on the dynamic role of its alteration during pathogenesis.

Topics: Arabidopsis; Carboxylic Ester Hydrolases; Cell Wall; Disease Resistance; Esterification; Host-Pathogen Interactions; Pectins; Plant Diseases; Virulence Factors

The constitutional isomers and tautomers of oxadiazolones, as well as their mono- and disulfur analogues, were calculated at the B3LYP/aug-cc-pVDZ level. Four groups of 30 molecules each were considered: oxadiazolone, oxadiazolthione, thiadiazolone, and thiadiazolthione isomers. The compounds were categorized into six groups according to permutations of three heteroatoms in the five-membered ring. Additionally, each of the constitutional isomer was considered to have five tautomers conserving stable five-membered ring: two NH tautomers, two rotameric OH (or SH) forms and one CH. La trombocitosis es un hallazgo casual frecuente en pediatría. En niños, predominan las formas secundarias, siendo las infecciones su causa más prevalente. Se distinguen 4 grados de trombocitosis en función del número de plaquetas; en la forma extrema, se supera el 1.000.000/mm. Endoscopic thrombin injection was similar to glue injection in achieving successful hemostasis of AGVH. However, a higher incidence of complications may be associated with glue injection.

Topics: Acetaminophen; Administration, Oral; Adolescent; Adsorption; Adult; Allyl Compounds; Amylopectin; Amylose; Anaerobiosis; Animals; Anti-Bacterial Agents; Anura; Arginase; Arthritis, Rheumatoid; Asthma; Atmosphere; B-Lymphocytes; Basic Helix-Loop-Helix Transcription Factors; Bioelectric Energy Sources; Biofilms; Biofuels; Biomarkers; Biopolymers; Bioreactors; Brain; Brain Injuries, Traumatic; Breast Neoplasms; Calibration; Carbon Tetrachloride; Caspase 3; Catalysis; Catechin; Cations; Cattle; CD4-Positive T-Lymphocytes; CD8-Positive T-Lymphocytes; Cell Body; Cell Line, Tumor; Cell Plasticity; Chemical and Drug Induced Liver Injury; Chemistry Techniques, Synthetic; China; Chitosan; Chloride Channels; Chromatography, High Pressure Liquid; Chromosome Mapping; Cognition; Cognitive Dysfunction; Cohort Studies; Colitis, Ulcerative; Colloids; Coloring Agents; Congresses as Topic; Correlation of Data; Crystallization; Cyanoacrylates; Cyclohexane Monoterpenes; Cyprinidae; Cytochrome P-450 CYP1A1; Death, Sudden; Dent Disease; Dietary Supplements; Diffusion Magnetic Resonance Imaging; Disease Models, Animal; Disease Progression; Disease Resistance; Disulfides; Drug Monitoring; Drug Stability; Ecotoxicology; Electricity; Electrodes; Endocytosis; Environmental Exposure; Environmental Monitoring; Enzyme Inhibitors; Epithelial-Mesenchymal Transition; Esophageal and Gastric Varices; Esters; Fagopyrum; Female; Ferrosoferric Oxide; Flame Retardants; Flavobacteriaceae; Flow Cytometry; Follow-Up Studies; Formoterol Fumarate; Fusarium; Garlic; Gastrointestinal Hemorrhage; Gene Expression; Genes, Plant; Genetic Markers; Glial Fibrillary Acidic Protein; Gliosis; Global Health; Glutathione Transferase; Glycine max; Gum Arabic; Hemostasis, Endoscopic; Hepatocytes; Hippocampus; Humans; Hydrogen-Ion Concentration; Illinois; Immunoglobulin G; Indoleamine-Pyrrole 2,3,-Dioxygenase; Infant, Newborn; Infant, Small for Gestational Age; Injections, Intraperitoneal; Interleukin-4; Iowa; Iron; Ki-67 Antigen; Kidney; Kinetics; Kynurenine; Lakes; Levofloxacin; Lipid Peroxidation; Lipids; Liver; Liver Cirrhosis, Experimental; Magnetic Fields; Magnetic Iron Oxide Nanoparticles; Male; Manure; Maze Learning; Memory, Short-Term; Metal Nanoparticles; Metals, Heavy; Methane; Mice; Mice, Inbred C57BL; Mice, Knockout; Michigan; Microalgae; Microbial Consortia; Mitochondria; Models, Animal; Models, Chemical; Models, Neurological; Molecular Structure; Molecular Weight; Mutation; Myeloid-Derived Suppressor Cells; NADPH Oxidase 2; Neoplasm Recurrence, Local; Neurites; Neurons; Neuroprotective Agents; NF-kappa B; NIH 3T3 Cells; Nitric Oxide Synthase Type II; Nitrogen; Ohio; Ointments; Ontario; Organelle Biogenesis; Organophosphates; Organophosphorus Compounds; Oxidative Stress; Palladium; Particle Size; Pectins; Phenotype; Phytotherapy; Piperidines; Placenta; Plant Diseases; Plant Extracts; Polymers; Polymorphism, Genetic; Polyphenols; Powders; Pregnancy; Pregnancy Trimester, First; Prospective Studies; Protein Kinase Inhibitors; Protein Structure, Secondary; Proteins; Pyridines; Pyrimidines; Rats, Wistar; Real-Time Polymerase Chain Reaction; Receptors, Aryl Hydrocarbon; Receptors, Chemokine; Receptors, Formyl Peptide; Receptors, Lipoxin; Recovery of Function; Recurrence; Reference Standards; Reference Values; Reproducibility of Results; Respiratory Function Tests; Retrospective Studies; Risk; Sensitivity and Specificity; Sewage; Signal Transduction; Sodium Glutamate; Soil; Solanum tuberosum; Solubility; Solutions; Spectroscopy, Fourier Transform Infrared; Spectrum Analysis; Spermatozoa; STAT3 Transcription Factor; Sulfamethoxazole; Tea; Temperature; Thermodynamics; Thrombin; Treatment Outcome; Triazoles; United States; Viscosity; Waste Disposal, Fluid; Wastewater; Water; Water Pollutants, Chemical; Water Purification; White Matter; Wisconsin; X-Ray Diffraction; Zea mays

In plants, long noncoding RNAs (lncRNAs) regulate disease resistance against fungi and other pathogens. However, the specific mechanism behind this regulation remains unclear. In this study, we identified disease resistance-related lncRNAs as well as their regulating genes and assessed their functions by infection of cotton (Gossypium) chromosome segment substitution lines with Verticillium dahliae. Our results demonstrated that lncRNA7 and its regulating gene Pectin methylesterase inhibitor 13 (GbPMEI13) positively regulated disease resistance via the silencing approach, while ectopic overexpression of GbPMEI13 in Arabidopsis (Arabidopsis thaliana) promoted growth and enhanced resistance to V. dahliae. In contrast, lncRNA2 and its regulating gene Polygalacturonase 12 (GbPG12) negatively regulated resistance to V. dahliae. We further found that fungal disease-related agents, including the pectin-derived oligogalacturonide (OG), could downregulate the expression of lncRNA2 and GbPG12, leading to pectin accumulation. Conversely, OG upregulated the expression of lncRNA7, which encodes a plant peptide phytosulfokine (PSK-α), which was confirmed by lncRNA7 overexpression and Ultra Performance Liquid Chromatography Tandem Mass Spectrometry (UPLC-MS) experiments. We showed that PSK-α promoted 3-Indoleacetic acid (IAA) accumulation and activated GbPMEI13 expression through Auxin Response Factor 5. Since it is an inhibitor of pectin methylesterase (PME), GbPMEI13 promotes pectin methylation and therefore increases the resistance to V. dahliae. Consistently, we also demonstrated that GbPMEI13 inhibits the mycelial growth and spore germination of V. dahliae in vitro. In this study, we demonstrated that lncRNA7, lncRNA2, and their regulating genes modulate cell wall defense against V. dahliae via auxin-mediated signaling, providing a strategy for cotton breeding.

Topics: Arabidopsis; Cell Wall; Chromatography, Liquid; Disease Resistance; Gene Expression Regulation, Plant; Gossypium; Indoleacetic Acids; Pectins; Plant Breeding; Plant Diseases; Plant Proteins; RNA, Long Noncoding; Tandem Mass Spectrometry; Verticillium

Pectin, a component of the plant cell wall, is involved in cell adhesion and environmental adaptations. We generated OsPG-FOX rice lines with little pectin due to overexpression of the gene encoding a pectin-degrading enzyme [polygalacturonase (PG)]. Overexpression of OsPG2 in rice under weak light conditions increased the activity of PG, which increased the degradation of pectin in the cell wall, thereby reducing adhesion. Under weak light conditions, the overexpression of OsPG decreased the pectin content and cell adhesion, resulting in abnormally large intercellular gaps and facilitating invasion by the rice blast fungus. OsPG2-FOX plants had weaker mechanical properties and greater sensitivity to biotic stresses than wild-type (WT) plants. However, the expression levels of disease resistance genes in non-infected leaves of OsPG2-FOX were more than twice as high as those of the WT and the intensity of disease symptoms was reduced, compared with the WT. Under normal light conditions, overexpression of OsPG2 decreased the pectin content, but did not affect cell adhesion and sensitivity to biotic stresses. Therefore, PG plays a role in regulating intercellular adhesion and the response to biotic stresses in rice.

Topics: Ascomycota; Biomechanical Phenomena; Cell Wall; Disease Resistance; Gene Expression Regulation, Plant; Host-Pathogen Interactions; Oryza; Pectins; Plant Diseases; Plant Leaves; Plants, Genetically Modified; Polygalacturonase; Promoter Regions, Genetic; Zea mays

GhMYB4 acts as a negative regulator in lignin biosynthesis, which results in alteration of cell wall integrity and activation of cotton defense response. Verticillium wilt of cotton (Gossypium hirsutum) caused by the soil-borne fungus Verticillium dahliae (V. dahliae) represents one of the most important constraints of cotton production worldwide. Mining of the genes involved in disease resistance and illuminating the molecular mechanisms that underlie this resistance is of great importance in cotton breeding programs. Defense-induced lignification in plants is necessary for innate immunity, and there are reports of a correlation between increased lignification and disease resistance. In this study, we present an example in cotton whereby plants with reduced lignin content also exhibit enhanced disease resistance. We identified a negative regulator of lignin synthesis, in cotton encoded in GhMYB4. Overexpression of GhMYB4 in cotton and Arabidopsis enhanced resistance to V. dahliae  with reduced lignin deposition. Moreover, GhMYB4 could bind the promoters of several genes involved in lignin synthesis, such as GhC4H-1, GhC4H-2, Gh4CL-4, and GhCAD-3, and impair their expression. The reduction of lignin content in GhMYB4-overexpressing cotton led to alterations of cell wall integrity (CWI) and released more oligogalacturonides (OGs) which may act as damage-associated molecular patterns (DAMPs) to stimulate plant defense responses. In support of this hypothesis, exogenous application with polygalacturonic acid (PGA) in cotton activated biosynthesis of jasmonic acid (JA) and JA-mediated defense against V. dahliae, similar to that described for cotton plants overexpressing GhMYB4. This study provides a new candidate gene for cotton disease-resistant breeding and an increased understanding of the relationship between lignin synthesis, OG release, and plant immunity.

Topics: Acetates; Arabidopsis; Ascomycota; Cyclopentanes; Disease Resistance; Gene Expression Regulation, Plant; Gossypium; Lignin; Oxylipins; Pectins; Phylogeny; Plant Diseases; Plant Immunity; Plant Proteins; Plants, Genetically Modified; Salicylic Acid; Transcription Factors

Temperature is one of the critical factors affecting gene expression in bacteria. Despite the general interest in the link between bacterial phenotypes and environmental temperature, little is known about temperature-dependent gene expression in plant pathogenic

Topics: Disease Resistance; DNA Transposable Elements; Gene Expression Regulation, Bacterial; Genome-Wide Association Study; Pectins; Pectobacterium; Plant Diseases; Solanum tuberosum; Temperature; Transposases

Topics: Arabidopsis; Arabidopsis Proteins; Ascomycota; Brassica napus; Cell Wall; Cellulose; Disease Resistance; Lignin; Pectins; Plant Diseases; Plants, Genetically Modified; RNA Interference; Transcription Factors; Xylem

Powdery mildew (Golovinomyces cichoracearum), one of the most prolific obligate biotrophic fungal pathogens worldwide, infects its host by penetrating the plant cell wall without activating the plant's innate immune system. The Arabidopsis mutant powdery mildew resistant 5 (pmr5) carries a mutation in a putative pectin acetyltransferase gene that confers enhanced resistance to powdery mildew. Here, we show that heterologously expressed PMR5 protein transfers acetyl groups from [

Topics: Acetyl Coenzyme A; Acetylation; Acetyltransferases; Arabidopsis; Arabidopsis Proteins; Ascomycota; Botrytis; Cell Wall; Cellulose; Disease Resistance; Mutation; Pectins; Phylogeny; Plant Diseases; Plant Leaves; Plants, Genetically Modified

In this study, we demonstrate the enhanced disease resistance and positive immunomodulation of novel pectin isolated from Spirulina maxima (SmP) in zebrafish model. Zebrafish larvae exposed to SmP had significantly (p < 0.05) higher cumulative percent survival (CPS) at 25 (44.0%) and 50 μg/mL (67.0%) against Edwardsiella piscicida compared to the control. However, upon Aeromonas hydrophila challenge, SmP exposed larvae at 50 μg/mL had slightly higher CPS (33.3%) compared to control group (26.7%). SmP supplemented zebrafish exhibited the higher CPS against E. piscicida (93.3%) and A. hydrophila (60.0%) during the early stage of post-infection (<18 hpi). qRT-PCR results demonstrated that exposing (larvae) and feeding (adults) of SmP, drive the modulation of a wide array of immune response genes. In SmP exposed larvae, up-regulation of the antimicrobial enzyme (lyz: 3.5-fold), mucin (muc5.1: 2.84, muc5.2: 2.11 and muc5.3: 2.40-fold), pro-inflammatory cytokines (il1β: 1.79-fold) and anti-oxidants (cat: 2.87 and sod1: 1.82-fold) were identified. In SmP fed adult zebrafish (gut) showed >2-fold induced pro-inflammatory cytokine (il1β) and chemokines (cxcl18b, ccl34a.4 and ccl34b.4). Overall results confirmed the positive modulation of innate immune responses in larval stage and it could be the main reason for developing disease resistance against E. piscicida and A. hydrophila. Thus, non-toxic, natural and biodegradable SmP could be considered as the potential immunomodulatory agent for sustainable aquaculture.

Topics: Aeromonas hydrophila; Animal Feed; Animals; Bacterial Proteins; Cyanobacteria; Diet; Dietary Proteins; Dietary Supplements; Disease Resistance; Edwardsiella; Enterobacteriaceae Infections; Fish Diseases; Gram-Negative Bacterial Infections; Immunity, Innate; Pectins; Zebrafish

The acquisition of susceptibility to necrotrophy over the course of ripening is one of the critical factors limiting shelf life. In this study, phytopathology and molecular biology were employed to explore the roles of pectinase in fruit susceptibility and ripening. Solanum lycopersicum fruit softened dramatically from entirely green to 50% red, which was accompanied by a continuously high expressed SlPG2 gene. The necrotrophic fungus Botrytis cinerea further activated the expression of SlPGs and SlPMEs to accelerate cell wall disassembly, while most of the polygalacturonase inhibitor proteins encoding genes expression were postponed in ripe fruit following the pathogen attack. Pectin induced the antagonistic yeast to secrete pectinolytic enzymes to increase fruit resistance against gray mold. The activities of pathogenic pectinase of B. cinerea were correspondingly depressed in the pectin-inducible yeast enzyme elicited ripe fruit. These data suggest that pectinase is a molecular target for regulation of disease resistance during fruit ripening.

Topics: Antibiosis; Botrytis; Disease Resistance; Fruit; Fungal Proteins; Gene Expression Regulation, Plant; Pectins; Plant Proteins; Polygalacturonase; Solanum lycopersicum; Yeasts

RNAi mediated silencing of pectin degrading enzyme of R. solani gives a high level of resistance against sheath blight disease of rice. Rice sheath blight disease caused by Rhizoctonia solani Kuhn (telemorph; Thanatephorus cucumeris) is one of the most devastating fungal diseases which cause severe loss to rice grain production. In the absence of resistant cultivars, the disease is currently managed through fungicides which add to environmental pollution. To explore the potential of utilizing RNA interference (RNAi)-mediated resistance against sheath blight disease, we identified genes encoding proteins and enzymes involved in the RNAi pathway in this fungal pathogen. The RNAi target genes were deciphered by RNAseq analysis of a highly virulent strain of the R. solani grown in pectin medium. Additionally, pectin metabolism associated genes of R. solani were analyzed through transcriptome sequencing of infected rice tissues obtained from six diverse rice cultivars. One of the key candidate gene AG1IA_04727 encoding polygalacturonase (PG), which was observed to be significantly upregulated during infection, was targeted through RNAi to develop disease resistance. Stable expression of PG-RNAi construct in rice showed efficient silencing of AG1IA_04727 and suppression of sheath blight disease. This study highlights important information about the existence of RNAi machinery and key genes of R. solani which can be targeted through RNAi to develop pathogen-derived resistance, thus opening an alternative strategy for developing sheath blight-resistant rice cultivars.

Topics: Disease Progression; Disease Resistance; Gene Expression Regulation, Plant; Genes, Plant; Oryza; Pectins; Plant Diseases; Polygalacturonase; Rhizoctonia; RNA Interference; RNA, Messenger; Sequence Analysis, RNA; Transcriptome; Transformation, Genetic

The present study investigates the effects of orange peels derived pectin (OPDP) on skin mucus and serum immune parameters, disease resistance and growth performance of O. niloticus cultured under indoor biofloc system. Six hundred Nile tilapia (average weight 9.09 ± 0.05 g) were distributed into 15 fiber tanks (300 L per tank) assigned to five treatments repeated in triplicate. Fish were fed experimental diets contain different levels OPDP as follows: 0 (control in clear water), 0 (control in biofloc system), 5, 10, and 20 g kg

Topics: Animals; Cichlids; Citrus sinensis; Complement Pathway, Alternative; Disease Resistance; Fish Diseases; Fruit; Immunity, Innate; Mucus; Muramidase; Pectins; Peroxidases; Phagocytosis; Respiratory Burst; Skin; Streptococcal Infections; Streptococcus agalactiae

Plant cell walls undergo dynamic structural and chemical changes during plant development and growth. Floral organ abscission and lateral root emergence are both accompanied by cell-wall remodeling, which involves the INFLORESCENCE DEFICIENT IN ABSCISSION (IDA)-derived peptide and its receptors, HAESA (HAE) and HAESA-LIKE2 (HSL2). Plant cell walls also act as barriers against pathogenic invaders. Thus, the cell-wall remodeling during plant development could have an influence on plant resistance to phytopathogens. Here, we identified IDA-like 6 (IDL6), a gene that is prominently expressed in Arabidopsis leaves. IDL6 expression in Arabidopsis leaves is significantly upregulated when the plant is suffering from attacks of the bacterial Pseudomonas syringae pv. tomato (Pst) DC3000. IDL6 overexpression and knockdown lines respectively decrease and increase the Arabidopsis resistance to Pst DC3000, indicating that the gene promotes the Arabidopsis susceptibility to Pst DC3000. Moreover, IDL6 promotes the expression of a polygalacturonase (PG) gene, ADPG2, and increases PG activity in Arabidopsis leaves, which in turn reduces leaf pectin content and leaf robustness. ADPG2 overexpression restrains Arabidopsis resistance to Pst DC3000, whereas ADPG2 loss-of-function mutants increase the resistance to the bacterium. Pst DC3000 infection elevates the ADPG2 expression partially through HAE and HSL2. Taken together, our results suggest that IDL6-HAE/HSL2 facilitates the ingress of Pst DC3000 by promoting pectin degradation in Arabidopsis leaves, and Pst DC3000 might enhance its infection by manipulating the IDL6-HAE/HSL2-ADPG2 signaling pathway.

Topics: Arabidopsis; Arabidopsis Proteins; Disease Resistance; Gene Expression Regulation, Plant; Pectins; Plant Diseases; Plant Leaves; Plants, Genetically Modified; Polygalacturonase; Protein Serine-Threonine Kinases; Pseudomonas syringae

The resistance to late blight is either qualitative or quantitative in nature. Quantitative resistance is durable, but challenging due to polygenic inheritance. In the present study, the diploid potato genotypes resistant and susceptible to late blight, were profiled for metabolites. Tissue specific metabolite analysis of benzylisoquinoline alkaloids (BIAs) in response to pathogen infection revealed increased accumulation of morphinone, codeine-6-glucuronide and morphine-3-glucuronides. These BIAs are antimicrobial compounds and possibly involved in cell wall reinforcement, especially through cross-linking cell wall pectins. Quantitative reverse transcription-PCR studies revealed higher expressions of TyDC, NCS, COR-2 and StWRKY8 transcription factor genes, in resistant genotypes than in susceptible genotype, following pathogen inoculation. A luciferase transient expression assay confirmed the binding of the StWRKY8 TF to promoters of downstream genes, elucidating a direct regulatory role on BIAs biosynthetic genes. Sequence analysis of StWRKY8 in potato genotypes revealed polymorphism in the WRKY DNA binding domain in the susceptible genotype, which is important for the regulatory function of this gene. A complementation assay of StWRKY8 in Arabidopsis wrky33 mutant background was associated with decreased fungal biomass. In conclusion, StWRKY8 regulates the biosynthesis of BIAs that are both antimicrobial and reinforce cell walls to contain the pathogen to initial infection.

Topics: Amino Acid Sequence; Arabidopsis; Arabidopsis Proteins; Benzylisoquinolines; Cell Wall; Disease Resistance; Gene Expression Regulation, Plant; Genes, Plant; Genotype; Pectins; Phytophthora infestans; Plant Diseases; Plant Proteins; Polymerase Chain Reaction; Polymorphism, Genetic; Promoter Regions, Genetic; Solanum tuberosum; Transcription Factors

Topics: Arabidopsis; Arabidopsis Proteins; Cell Wall; Cellobiose; Cellulose; Disaccharides; Disease Resistance; Gene Expression Profiling; Gene Expression Regulation, Plant; Host-Pathogen Interactions; Mutation; Oligosaccharides; Pectins; Plant Diseases; Plants, Genetically Modified; Promoter Regions, Genetic; Pseudomonas syringae; Reverse Transcriptase Polymerase Chain Reaction; Seedlings; Transcription Factors

The genome of Fusarium graminearum, the causal agent of Fusarium head blight of wheat, contains two putative pectin methylesterase (PME)-encoding genes. However, when grown in liquid culture containing pectin, F. graminearum produces only a single PME, which was purified and identified. Its encoding gene, expressed during wheat spike infection, was disrupted by targeted homologous recombination. Two Δpme mutant strains lacked PME activity but were still able to grow on highly methyl-esterified pectin even though their polygalacturonase (PG) activity showed a reduced capacity to depolymerize this substrate. The enzymatic assays performed with purified F. graminearum PG and PME demonstrated an increase in PG activity in the presence of PME on highly methyl-esterified pectin. The virulence of the mutant strains was tested on Triticum aestivum and Triticum durum spikes, and a significant reduction in the percentage of symptomatic spikelets was observed between 7 and 12 days postinfection compared with wild type, demonstrating that the F. graminearum PME contributes to fungal virulence on wheat by promoting spike colonization in the initial and middle stages of infection. In contrast, transgenic wheat plants with increased levels of pectin methyl esterification did not show any increase in resistance to the Δpme mutant, indicating that the infectivity of the fungus relies only to a certain degree on pectin degradation.

Topics: Carboxylic Ester Hydrolases; Disease Resistance; Esterification; Fungal Proteins; Fusarium; Mutation; Pectins; Plant Diseases; Plants, Genetically Modified; Triticum

ERF transcription factors play critical roles in plant immune responses. Here, we report the function of AtERF014, a nucleus-localized transcriptional activator, in Arabidopsis immunity. Expression of AtERF014 was induced by Pseudomonas syringae pv. tomato (Pst) and Botrytis cinerea (Bc). AtERF014-overexpressing (OE) plants displayed increased Pst resistance but decreased Bc resistance, whereas AtERF014-RNAi plants exhibited decreased Pst resistance but increased Bc resistance. After Pst infection, expression of salicylic acid (SA)-responsive genes AtPR1 and AtPR5 in AtERF014-OE plants and of a jasmonic acid/ethylene-responsive gene AtPDF1.2 in AtERF014-RNAi plants was intensified but expression of AtPDF1.2 in AtERF014-OE plants and of AtPR1 and AtPR5 in AtERF014-RNAi plants was weakened. After Bc infection, expression of AtPR1 and AtPR5 in AtERF014-OE plants was attenuated but expression of AtPR1, AtPR5 and AtPDF1.2 in AtERF014-RNAi plants was strengthened. Pathogen- and flg22-induced ROS burst, expression of PTI genes and SA-induced defense were partially suppressed in AtERF014-RNAi plants, whereas pathogen-induced ROS and flg22-induced immune response were strengthened in AtER014-OE plants. Altered expression of AtERR014 affected expression of pectin biosynthetic genes and pectin content in AtERF014-RNAi plants was decreased. These data demonstrate that AtERF014 acts as a dual regulator that differentially modulates immunity against Pst and Bc in Arabidopsis.

Topics: Arabidopsis; Arabidopsis Proteins; Botrytis; Cyclopentanes; Defensins; Disease Resistance; DNA-Binding Proteins; Ethylenes; Gene Expression Regulation, Plant; Oxylipins; Pectins; Plant Diseases; Plant Immunity; Pseudomonas syringae; Salicylic Acid; Transcription Factors

Host plant penetration is the gateway to survival for holoparasitic Cuscuta and requires host cell wall degradation. Compositional differences of cell walls may explain why some hosts are amenable to such degradation while others can resist infection. Antibody-based techniques for comprehensive profiling of cell wall epitopes and cell wall-modifying enzymes were applied to several susceptible hosts and a resistant host of Cuscuta reflexa and to the parasite itself. Infected tissue of Pelargonium zonale contained high concentrations of de-esterified homogalacturonans in the cell walls, particularly adjacent to the parasite's haustoria. High pectinolytic activity in haustorial extracts and high expression levels of pectate lyase genes suggest that the parasite contributes directly to wall remodeling. Mannan and xylan concentrations were low in P. zonale and in five susceptible tomato introgression lines, but high in the resistant Solanum lycopersicum cv M82, and in C. reflexa itself. Knowledge of the composition of resistant host cell walls and the parasite's own cell walls is useful in developing strategies to prevent infection by parasitic plants.

Topics: Animals; Cell Wall; Cuscuta; Disease Resistance; Epitopes; Glucans; Host-Parasite Interactions; Metabolomics; Microarray Analysis; Parasites; Pectins; Pelargonium; Plant Diseases; Plant Stems; Plants, Genetically Modified; Polysaccharide-Lyases; Polysaccharides; Solanum lycopersicum; Xylans

The plant cell wall constitutes an essential protection barrier against pathogen attack. In addition, cell-wall disruption leads to accumulation of jasmonates (JAs), which are key signaling molecules for activation of plant inducible defense responses. However, whether JAs in return modulate the cell-wall composition to reinforce this defensive barrier remains unknown. The enzyme 13-allene oxide synthase (13-AOS) catalyzes the first committed step towards biosynthesis of JAs. In potato (Solanum tuberosum), there are two putative St13-AOS genes, which we show here to be differentially induced upon wounding. We also determine that both genes complement an Arabidopsis aos null mutant, indicating that they encode functional 13-AOS enzymes. Indeed, transgenic potato plants lacking both St13-AOS genes (CoAOS1/2 lines) exhibited a significant reduction of JAs, a concomitant decrease in wound-responsive gene activation, and an increased severity of soft rot disease symptoms caused by Dickeya dadantii. Intriguingly, a hypovirulent D. dadantii pel strain lacking the five major pectate lyases, which causes limited tissue maceration on wild-type plants, regained infectivity in CoAOS1/2 plants. In line with this, we found differences in pectin methyl esterase activity and cell-wall pectin composition between wild-type and CoAOS1/2 plants. Importantly, wild-type plants had pectins with a lower degree of methyl esterification, which are the substrates of the pectate lyases mutated in the pel strain. These results suggest that, during development of potato plants, JAs mediate modification of the pectin matrix to form a defensive barrier that is counteracted by pectinolytic virulence factors from D. dadantii.

Topics: Arabidopsis; Bacterial Proteins; Carboxylic Ester Hydrolases; Cell Wall; Cyclopentanes; Disease Resistance; Enterobacteriaceae; Esterification; Host-Pathogen Interactions; Intramolecular Oxidoreductases; Mutation; Oxylipins; Pectins; Plant Diseases; Plant Growth Regulators; Plant Leaves; Plant Proteins; Plants, Genetically Modified; Polysaccharide-Lyases; Solanum tuberosum; Virulence Factors; Wounds and Injuries

Since tomato is an important food component, it is imperative to enhance its yield against the activities of many devastating fungal pathogens such as Alternaria alternata. The exploitation of plant innate resistance by cultivation of resistant varieties is an effective measure in this regard. In the present study, 28 tomato varieties were tested against 32 A. alternata isolates, and representative varieties were further evaluated to determine the extent and basis of their antifungal resistance.. A significant increase (104.7%) in polyphenols was recorded in the resistant variety Dinaar compared with the susceptible variety Red Tara. Dinaar also exhibited 100% enhancement of alkaloids and terpenoids along with a 30.7% increase in cell wall hemicellulose content. Significant differences were found in physical barriers (cellulose, lignin and pectin) of the representative varieties when stained tissue sections were subjected to colorimetric analysis. Similarly, polyphenol oxidase, peroxidase and phenylalanine ammonia lyase showed increases of 78.37, 114.67 and 125.11% respectively in the resistant variety. Higher expression of glucanase genes was evident from native gel analysis, in which not only the number of isozymes but also the quantity of individual isozymes was significantly increased.. The resistant variety Dinaar had strong antifungal resistance and can therefore be recommended as suitable for cultivation in the agricultural system of Pakistan.

Topics: Alkaloids; Alternaria; Catechol Oxidase; Cellulose; Disease Resistance; Pakistan; Pectins; Peroxidases; Phenylalanine Ammonia-Lyase; Plant Diseases; Plant Leaves; Plant Proteins; Polyphenols; Solanum lycopersicum; Species Specificity; Terpenes; Virulence

The plant cell wall has many significant structural and physiological roles, but the contributions of the various components to these roles remain unclear. Modification of cell wall properties can affect key agronomic traits such as disease resistance and plant growth. The plant cell wall is composed of diverse polysaccharides often decorated with methyl, acetyl, and feruloyl groups linked to the sugar subunits. In this study, we examined the effect of perturbing cell wall acetylation by making transgenic Arabidopsis (Arabidopsis thaliana) and Brachypodium (Brachypodium distachyon) plants expressing hemicellulose- and pectin-specific fungal acetylesterases. All transgenic plants carried highly expressed active Aspergillus nidulans acetylesterases localized to the apoplast and had significant reduction of cell wall acetylation compared with wild-type plants. Partial deacetylation of polysaccharides caused compensatory up-regulation of three known acetyltransferases and increased polysaccharide accessibility to glycosyl hydrolases. Transgenic plants showed increased resistance to the fungal pathogens Botrytis cinerea and Bipolaris sorokiniana but not to the bacterial pathogens Pseudomonas syringae and Xanthomonas oryzae. These results demonstrate a role, in both monocot and dicot plants, of hemicellulose and pectin acetylation in plant defense against fungal pathogens.

Topics: Acetylation; Acetylesterase; Arabidopsis; Ascomycota; Aspergillus nidulans; Botrytis; Brachypodium; Cell Wall; Disease Resistance; Fungal Proteins; Gene Expression Regulation, Plant; Glucans; Hydrogen Peroxide; Pectins; Plant Components, Aerial; Plant Diseases; Plants, Genetically Modified; Polysaccharides; Pseudomonas syringae; Up-Regulation; Xanthomonas

Claviceps purpurea is a biotrophic fungal pathogen of grasses causing the ergot disease. The infection process of C. purpurea on rye flowers is accompanied by pectin degradation and polygalacturonase (PG) activity represents a pathogenicity factor. Wheat is also infected by C. purpurea and we tested whether the presence of polygalacturonase inhibiting protein (PGIP) can affect pathogen infection and ergot disease development. Wheat transgenic plants expressing the bean PvPGIP2 did not show a clear reduction of disease symptoms when infected with C. purpurea. To ascertain the possible cause underlying this lack of improved resistance of PvPGIP2 plants, we expressed both polygalacturonases present in the C. purpurea genome, cppg1 and cppg2 in Pichia pastoris. In vitro assays using the heterologous expressed PGs and PvPGIP2 showed that neither PG is inhibited by this inhibitor. To further investigate the role of PG in the C. purpurea/wheat system, we demonstrated that the activity of both PGs of C. purpurea is reduced on highly methyl esterified pectin. Finally, we showed that this reduction in PG activity is relevant in planta, by inoculating with C. purpurea transgenic wheat plants overexpressing a pectin methyl esterase inhibitor (PMEI) and showing a high degree of pectin methyl esterification. We observed reduced disease symptoms in the transgenic line compared with null controls. Together, these results highlight the importance of pectin degradation for ergot disease development in wheat and sustain the notion that inhibition of pectin degradation may represent a possible route to control of ergot in cereals.

Topics: Carboxylic Ester Hydrolases; Claviceps; Disease Resistance; Esterification; Genes, Plant; Pectins; Phaseolus; Pichia; Plant Diseases; Plant Proteins; Plants, Genetically Modified; Polygalacturonase; Triticum