scholarly journals Potyviral Gene-Silencing Suppressor HCPro Interacts with Salicylic Acid (SA)-Binding Protein 3 to Weaken SA-Mediated Defense Responses

2018 ◽  
Vol 31 (1) ◽  
pp. 86-100 ◽  
Author(s):  
Sylvain Poque ◽  
Hui-Wen Wu ◽  
Chung-Hao Huang ◽  
Hao-Wen Cheng ◽  
Wen-Chi Hu ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Viral Infection ◽  
Host Defense ◽  
Binding Protein ◽  
Constitutive Expression ◽  
Defense Responses ◽  
Negative Regulator ◽  
Bimolecular Fluorescence Complementation ◽  
Silencing Suppressor ◽  
Ability To Act

The viral infection process is a battle between host defense response and pathogen antagonizing action. Several studies have established a tight link between the viral RNA silencing suppressor (RSS) and the repression of salicylic acid (SA)-mediated defense responses, nonetheless host factors directly linking an RSS and the SA pathway remains unidentified. From yeast two-hybrid analysis, we identified an interaction between the potyviral RSS helper-component proteinase (HCPro) and SA–binding protein SABP3. Co-localization and bimolecular fluorescence complementation analyses validated the direct in vivo interaction between Turnip mosaic virus (TuMV) HCPro and the Arabidopsis homologue of SABP3, AtCA1. Additionally, transient expression of TuMV HCPro demonstrated its ability to act as a negative regulator of AtCA1. When the plants of the AtCA1 knockout mutant line were inoculated with TuMV, our results indicated that AtCA1 is essential to restrict viral spreading and accumulation, induce SA accumulation, and trigger the SA pathway. Unexpectedly, the AtCA1 overexpression line also displayed a similar phenotype, suggesting that the constitutive expression of AtCA1 antagonizes the SA pathway. Taken together, our results depict AtCA1 as an essential regulator of SA defense responses. Moreover, the interaction of potyviral HCPro with this regulator compromises the SA pathway to weaken host defense responses and facilitate viral infection.

scholarly journals Arabidopsis CALMODULIN-BINDING PROTEIN 60b plays dual roles in plant immunity

2021 ◽  
Author(s):  
Weijie Huang ◽  
Zhongshou Wu ◽  
Hainan Tian ◽  
Xin Li ◽  
Yuelin Zhang
Keyword(s):  
Systemic Acquired Resistance ◽  
Binding Protein ◽  
Plant Immunity ◽  
Interleukin 1 ◽  
Constitutive Expression ◽  
Defense Responses ◽  
Negative Regulator ◽  
Loss Of Function ◽  
Constitutive Defense ◽  
Calmodulin Binding

AbstractArabidopsis SYSTEMIC ACQUIRED RESISTANCE DEFICIENT 1 (SARD1) and CALMODULIN-BINDING PROTEIN 60g (CBP60g) are two master transcription factors that regulate many defense-related genes in plant immunity. They are required for immunity downstream of the receptor-like protein SUPPRESSOR OF NPR1-1, CONSTITUTIVE 2 (SNC2). Constitutive defense responses in the gain-of-function autoimmune snc2-1D mutant are modestly affected by either sard1 or cbp60g single mutants, but completely suppressed by the sard1 cbp60g double mutant. Here we report that CBP60b, another member of the CBP60 family, also functions as a positive regulator of SNC2-mediated immunity. Loss-of-function mutations of CBP60b suppress the constitutive expression of SARD1 and enhanced disease resistance in cbp60g-1 snc2-1D, whereas over-expression of CBP60b leads to elevated SARD1 expression and constitutive defense responses. In addition, transient expression of CBP60b in Nicotiana benthamiana activates the expression of the pSARD1::luciferase reporter gene. Chromatin immunoprecipitation assay further showed that CBP60b is recruited to the promoter region of SARD1, suggesting that it directly regulates SARD1 expression. Interestingly, knocking out CBP60b in the wild type background leads to ENHANCED DISEASE SUSCEPTIBILITY 1 (EDS1)-dependent autoimmunity, suggesting that CBP60b is required for the expression of a guardee/decoy or a negative regulator in immunity mediated by receptors carrying an N-terminal TIR (Toll-interleukin-1 receptor-like) domain.Significance statementArabidopsis SARD1 serves as a master transcription factor in plant immunity. In this study, we showed that CBP60b positively regulates SARD1 expression, and TIR signaling is activated when CBP60b is inactivated.

scholarly journals Expression analysis of host defense responses against the 8K (KDa) cysteine-rich viral silencing suppressor protein in Nicotiana benthamiana

Plant Omics ◽  
2018 ◽  
Vol 11 (02) ◽  
pp. 113-119
Author(s):  
Aminallah Tahmasebi ◽  
◽  
Alireza Afsharifar ◽  
Ahmad Heydari ◽  
Mohammad Mehrabadi ◽  
...  
Keyword(s):  
Expression Analysis ◽  
Host Defense ◽  
Nicotiana Benthamiana ◽  
Defense Responses ◽  
Silencing Suppressor ◽  
Viral Silencing Suppressor

scholarly journals Epigenetic Malleability at Core Promoter Regulates Tobacco PR-1a Expression after Salicylic Acid Treatment

2021 ◽  
Author(s):  
Niraj Lodhi ◽  
Mala Singh ◽  
Rakesh Srivastva ◽  
Samir V Sawant ◽  
Rakesh Tuli
Keyword(s):  
Salicylic Acid ◽  
Transcription Initiation ◽  
Core Promoter ◽  
Constitutive Expression ◽  
Inducible Promoter ◽  
Epigenetic Modifications ◽  
Negative Regulator ◽  
Repressor Complex ◽  
Pathogenesis Related ◽  
Strict Regulation

Tobaccos PR-1a gene is induced by pathogen attack or exogenous application of Salicylic Acid (SA). However, the epigenetic modifications of the most important inducible promoter of the PR-1a gene are not understood clearly. Nucelosome mapping and chromatin immunoprecipitation assay were used to define the histone modification on the PR-1a promoter. Here, we report the epigenetic modifications over core promoter lead to disassembly of nucleosome (spans from -102 to +55 bp) masks TATA and transcription initiation) and repressor complex in induced state. ChIP assays demonstrate repressive chromatin of di-methylation at H3K9 and H4K20 of core promoter maintain uninduced state. While, active chromatin marks di and trimethylation of H3K4, acetylation of H3K9 and H4K16 are increased and lead the induction of PR-1a following SA treatment. TSA enhances expression of PR-1a by facilitating the histone acetylation, however increased expression of negative regulator (SNI1) of AtPR1, suppresses its expression in Arabidopsis thalianas mutants. Constitutive expression of AtPR1 in Histone Acetyl Transferases (HATs), LSD1, and SNI1 suggests that its inactive state is indeed maintained by a repressive complex and this strict regulation of pathogenesis related genes is conserved across species.

scholarly journals Type 2C Phosphatase 1 ofArtemisia annuaL. Is a Negative Regulator of ABA Signaling

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Fangyuan Zhang ◽  
Xueqing Fu ◽  
Zongyou Lv ◽  
Qian Shen ◽  
Tingxian Yan ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Artemisia Annua ◽  
Phosphorylation Site ◽  
Constitutive Expression ◽  
Negative Regulator ◽  
Bimolecular Fluorescence Complementation ◽  
Transcriptional Analysis ◽  
Aba Signaling ◽  
Environmental Stress Response ◽  
Positive Role

The phytohormone abscisic acid (ABA) plays an important role in plant development and environmental stress response. Additionally, ABA also regulates secondary metabolism such as artemisinin in the medicinal plantArtemisia annuaL. Although an earlier study showed that ABA receptor, AaPYL9, plays a positive role in ABA-induced artemisinin content improvement, many components in the ABA signaling pathway remain to be elucidated inArtemisia annuaL. To get insight of the function of AaPYL9, we isolated and characterized an AaPYL9-interacting partner, AaPP2C1. The coding sequence of AaPP2C1 encodes a deduced protein of 464 amino acids, with all the features of plant type clade A PP2C. Transcriptional analysis showed that the expression level of AaPP2C1 is increased after ABA, salt, and drought treatments. Yeast two-hybrid and bimolecular fluorescence complementation assays (BiFC) showed that AaPYL9 interacted with AaPP2C1. The P89S, H116A substitution in AaPYL9 as well as G199D substitution or deletion of the third phosphorylation site-like motif in AaPP2C1 abolished this interaction. Furthermore, constitutive expression of AaPP2C1 conferred ABA insensitivity compared with the wild type. In summary, our data reveals that AaPP2C1 is an AaPYL9-interacting partner and involved in the negative modulation of the ABA signaling pathway inA. annuaL.

scholarly journals Vitamin D receptor, vitamin D binding protein and CYP27B1 single nucleotide polymorphisms and susceptibility to viral infections in infants

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Maria Zacharioudaki ◽  
Ippokratis Messaritakis ◽  
Emmanouil Galanakis
Keyword(s):  
Vitamin D ◽  
Single Nucleotide Polymorphisms ◽  
Viral Infection ◽  
Vitamin D Receptor ◽  
Viral Infections ◽  
Binding Protein ◽  
Genotypic Differences ◽  
Nucleotide Polymorphisms ◽  
Vitamin D Binding Protein ◽  
Single Nucleotide

AbstractThe role of vitamin D in innate and adaptive immunity is recently under investigation. In this study we explored the potential association of genetic variances in vitamin D pathway and infections in infancy. Τhis prospective case–control study included infants 0–24 months with infection and age-matched controls. The single nucleotide polymorphisms of vitamin D receptor (VDR) gene (BsmI, FokI, ApaI, TaqI), vitamin D binding protein (VDBP) (Gc gene, rs7041, rs4588) and CYP27B1 (rs10877012) were genotyped by polymerase chain reaction-restriction fragment length polymorphism. In total 132 infants were enrolled, of whom 40 with bacterial and 52 with viral infection, and 40 healthy controls. As compared to controls, ΤaqI was more frequent in infants with viral infection compared to controls (p = 0.03, OR 1.96, 95% CI 1.1–3.58). Moreover, Gc1F was more frequent in the control group compared to infants with viral infection (p = 0.007, OR 2.7, 95% CI 1.3–5.6). No significant differences were found regarding the genetic profile for VDR and VDBP in infants with bacterial infection compared to the controls and also regarding CYP27B1 (rs10877012) between the studied groups. Genotypic differences suggest that vitamin D pathway might be associated with the host immune response against viral infections in infancy.

scholarly journals The Arabidopsis mediator complex subunit 8 regulates oxidative stress responses

2021 ◽  
Author(s):  
Huaming He ◽  
Jordi Denecker ◽  
Katrien Van Der Kelen ◽  
Patrick Willems ◽  
Robin Pottie ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Salicylic Acid ◽  
Jasmonic Acid ◽  
Stress Responses ◽  
Negative Regulator ◽  
Mediator Complex ◽  
Defense Gene Expression ◽  
A Genome ◽  
Oxidative Stress Responses

Abstract Signaling events triggered by hydrogen peroxide (H2O2) regulate plant growth and defense by orchestrating a genome-wide transcriptional reprogramming. However, the specific mechanisms that govern H2O2-dependent gene expression are still poorly understood. Here, we identify the Arabidopsis Mediator complex subunit MED8 as a regulator of H2O2 responses. The introduction of the med8 mutation in a constitutive oxidative stress genetic background (catalase-deficient, cat2) was associated with enhanced activation of the salicylic acid pathway and accelerated cell death. Interestingly, med8 seedlings were more tolerant to oxidative stress generated by the herbicide methyl viologen (MV) and exhibited transcriptional hyperactivation of defense signaling, in particular salicylic acid- and jasmonic acid-related pathways. The med8-triggered tolerance to MV was manipulated by the introduction of secondary mutations in salicylic acid and jasmonic acid pathways. In addition, analysis of the Mediator interactome revealed interactions with components involved in mRNA processing and microRNA biogenesis, hence expanding the role of Mediator beyond transcription. Notably, MED8 interacted with the transcriptional regulator NEGATIVE ON TATA-LESS, NOT2, to control the expression of H2O2-inducible genes and stress responses. Our work establishes MED8 as a component regulating oxidative stress responses and demonstrates that it acts as a negative regulator of H2O2-driven activation of defense gene expression.

scholarly journals Free and Conjugated Benzoic Acid in Tobacco Plants and Cell Cultures. Induced Accumulation upon Elicitation of Defense Responses and Role as Salicylic Acid Precursors

2001 ◽  
Vol 125 (1) ◽  
pp. 318-328 ◽  
Author(s):  
Julie Chong ◽  
Marie-Agnès Pierrel ◽  
Rossitza Atanassova ◽  
Danièle Werck-Reichhart ◽  
Bernard Fritig ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Benzoic Acid ◽  
Cell Cultures ◽  
Defense Responses ◽  
Tobacco Plants

scholarly journals Salicylic Acid Biosynthesis and Metabolism: A Divergent Pathway for Plants and Bacteria

Biomolecules ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 705
Author(s):  
Awdhesh Kumar Mishra ◽  
Kwang-Hyun Baek
Keyword(s):  
Salicylic Acid ◽  
Bacterial Species ◽  
Shikimate Pathway ◽  
Gene Clusters ◽  
Defense Responses ◽  
Biosynthetic Gene ◽  
Biosynthetic Enzyme ◽  
Biosynthetic Gene Clusters ◽  
Acid Biosynthesis ◽  
Common Precursor

Salicylic acid (SA) is an active secondary metabolite that occurs in bacteria, fungi, and plants. SA and its derivatives (collectively called salicylates) are synthesized from chorismate (derived from shikimate pathway). SA is considered an important phytohormone that regulates various aspects of plant growth, environmental stress, and defense responses against pathogens. Besides plants, a large number of bacterial species, such as Pseudomonas, Bacillus, Azospirillum, Salmonella, Achromobacter, Vibrio, Yersinia, and Mycobacteria, have been reported to synthesize salicylates through the NRPS/PKS biosynthetic gene clusters. This bacterial salicylate production is often linked to the biosynthesis of small ferric-ion-chelating molecules, salicyl-derived siderophores (known as catecholate) under iron-limited conditions. Although bacteria possess entirely different biosynthetic pathways from plants, they share one common biosynthetic enzyme, isochorismate synthase, which converts chorismate to isochorismate, a common precursor for synthesizing SA. Additionally, SA in plants and bacteria can undergo several modifications to carry out their specific functions. In this review, we will systematically focus on the plant and bacterial salicylate biosynthesis and its metabolism.

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