scholarly journals NINJA-Associated ERF19 Negatively Regulates Arabidopsis Pattern-Triggered Immunity

2017 ◽  
Author(s):  
Pin-Yao Huang ◽  
Jingsong Zhang ◽  
Beier Jiang ◽  
Jhong-He Yu ◽  
Yu-Ping Lu ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Defense Responses ◽  
Negative Regulator ◽  
Fine Tuning ◽  
Ethylene Response Factor ◽  
Negative Role ◽  
Erf Family ◽  
Complex Signaling ◽  
Molecular Patterns

ABSTRACTRecognition of microbe-associated molecular patterns (MAMPs) derived from invading pathogens by plant pattern recognition receptors (PRRs) initiates defense responses known as pattern-triggered immunity (PTI). Transcription factors (TFs) orchestrate the onset of PTI through complex signaling networks. Here, we characterize the function of ERF19, a member of the Arabidopsis thaliana ethylene response factor (ERF) family. ERF19 was found to act as a negative regulator of PTI against Botrytis cinerea and Pseudomonas syringae pv. tomato DC3000 (Pst). Notably, overexpression of ERF19 increased plant susceptibility to these pathogens and repressed MAMP-induced PTI outputs. In contrast, expression of the chimeric dominant repressor ERF19-SRDX boosted PTI activation, conferred increased resistance to B. cinerea, and enhanced elf18-triggered immunity against Pst. Consistent with a negative role of ERF19 in PTI, MAMP-mediated growth inhibition was respectively weakened or augmented in lines overexpressing ERF19 or expressing ERF19-SRDX. Moreover, we demonstrate that the transcriptional repressor Novel INteractor of JAZ (NINJA) associates with and represses the function of ERF19. Our work reveals ERF19 as a key player in a buffering mechanism to avoid defects imposed by over-activation of PTI and a potential role for NINJA in fine-tuning ERF19-mediated regulation.

scholarly journals The Arabidopsis ATAF1, a NAC Transcription Factor, Is a Negative Regulator of Defense Responses Against Necrotrophic Fungal and Bacterial Pathogens

2009 ◽  
Vol 22 (10) ◽  
pp. 1227-1238 ◽  
Author(s):  
Xiao'e Wang ◽  
B. M. Vindhya S. Basnayake ◽  
Huijuan Zhang ◽  
Guojun Li ◽  
Wei Li ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Bacterial Pathogens ◽  
Defense Responses ◽  
Ethylene Biosynthesis ◽  
Negative Regulator ◽  
Alternaria Brassicicola ◽  
Tomato Dc3000 ◽  
Pathogenesis Related ◽  
Direct Genetic Evidence

Transcription factors of the NAC family are known to be involved in various growth or developmental processes and in regulation of response to environmental stresses. In the present study, we report that Arabidopsis ATAF1 is a negative regulator of defense responses against both necrotrophic fungal and bacterial pathogens. Expression of ATAF1 was downregulated after infection with Botrytis cinerea or Pseudomonas syringae pv. tomato or after treatment with salicylic acid (SA), jasmonic acid, and 1-amino cyclopropane-1-carboxylic acid (the precursor of ethylene biosynthesis). Transgenic plants that overexpress the ATAF1 gene (ATAF1-OE) showed increased susceptibility while expression of an ATAF1 chimeric repressor construct (ATAF1-SRDX) exhibited enhanced resistance to P. syringae pv. tomato DC3000, B. cinerea, and Alternaria brassicicola. The ataf1 mutant plants showed no significant resistance against the pathogens tested. After inoculation with B. cinerea or P. syringae pv. tomato DC3000, expressions of defense-related genes PR-1, PR-5. and PDF1.2 were upregulated in the ATAF1-SRDX plants but attenuated or unchanged in the ATAF1-OE plants. In ATAF1-OE plants, SA-induced expression of pathogenesis-related genes and disease resistance against P. syringae pv. tomato DC3000 was partially suppressed. Increased levels of reactive oxygen species (i.e., H2O2 and superoxide anion) accumulated only in the ATAF1-OE but not in the ATAF1-SRDX plants after Botrytis spp. infection. Our studies provide direct genetic evidence for the role of ATAF1 as a negative regulator of defense response against different type of pathogens.

scholarly journals The Role of Peptide Signals Hidden in the Structure of Functional Proteins in Plant Immune Responses

2019 ◽  
Vol 20 (18) ◽  
pp. 4343 ◽  
Author(s):  
Irina Lyapina ◽  
Anna Filippova ◽  
Igor Fesenko
Keyword(s):  
Immune Responses ◽  
Defense Responses ◽  
Innate Immune ◽  
Functional Protein ◽  
Diverse Range ◽  
Peptide Signals ◽  
Plant Pathogen Interactions ◽  
Molecular Patterns ◽  
Damage Associated Molecular Patterns

Plants have evolved a sophisticated innate immune system to cope with a diverse range of phytopathogens and insect herbivores. Plasma-membrane-localized pattern recognition receptors (PRRs), such as receptor-like kinases (RLK), recognize special signals, pathogen- or damage-associated molecular patterns (PAMPs or DAMPs), and trigger immune responses. A growing body of evidence shows that many peptides hidden in both plant and pathogen functional protein sequences belong to the group of such immune signals. However, the origin, evolution, and release mechanisms of peptide sequences from functional and nonfunctional protein precursors, known as cryptic peptides, are largely unknown. Various special proteases, such as metacaspase or subtilisin-like proteases, are involved in the release of such peptides upon activation during defense responses. In this review, we discuss the roles of cryptic peptide sequences hidden in the structure of functional proteins in plant defense and plant-pathogen interactions.

scholarly journals SMAD7 antagonizes key TGFβ superfamily signaling in mouse granulosa cells in vitro

Reproduction ◽  
2013 ◽  
Vol 146 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Yang Gao ◽  
Haixia Wen ◽  
Chao Wang ◽  
Qinglei Li
Keyword(s):  
Granulosa Cell ◽  
Granulosa Cells ◽  
Transforming Growth Factor ◽  
Negative Regulator ◽  
Fine Tuning ◽  
Female Reproduction ◽  
Tgfβ Signaling ◽  
Tgfβ Superfamily

Transforming growth factor β (TGFβ) superfamily signaling is essential for female reproduction. Dysregulation of the TGFβ signaling pathway can cause reproductive diseases. SMA and MAD (mothers against decapentaplegic) (SMAD) proteins are downstream signaling transducers of the TGFβ superfamily. SMAD7 is an inhibitory SMAD that regulates TGFβ signalingin vitro. However, the function of SMAD7 in the ovary remains poorly defined. To determine the signaling preference and potential role of SMAD7 in the ovary, we herein examined the expression, regulation, and function of SMAD7 in mouse granulosa cells. We showed that SMAD7 was expressed in granulosa cells and subject to regulation by intraovarian growth factors from the TGFβ superfamily. TGFB1 (TGFβ1), bone morphogenetic protein 4, and oocyte-derived growth differentiation factor 9 (GDF9) were capable of inducingSmad7expression, suggesting a modulatory role of SMAD7 in a negative feedback loop. Using a small interfering RNA approach, we further demonstrated that SMAD7 was a negative regulator of TGFB1. Moreover, we revealed a link between SMAD7 and GDF9-mediated oocyte paracrine signaling, an essential component of oocyte–granulosa cell communication and folliculogenesis. Collectively, our results suggest that SMAD7 may function during follicular development via preferentially antagonizing and/or fine-tuning essential TGFβ superfamily signaling, which is involved in the regulation of oocyte–somatic cell interaction and granulosa cell function.

scholarly journals FOXA3, a Negative Regulator of Nur77 Expression and Activity in Testicular Steroidogenesis

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Hansle Kim ◽  
Sudeep Kumar ◽  
Keesook Lee
Keyword(s):  
Leydig Cells ◽  
Adenosine Monophosphate ◽  
Negative Regulator ◽  
Fine Tuning ◽  
Camp Signaling ◽  
Orphan Nuclear Receptor ◽  
Repressive Effect ◽  
Testicular Steroidogenesis ◽  
Steroidogenic Genes

Biosynthesis of testosterone occurs mainly in the testicular Leydig cells. Nur77, an orphan nuclear receptor that is expressed in response to the luteinizing hormone/cyclic adenosine monophosphate (LH/cAMP) signaling pathway, is one of the key factors that regulate steroidogenesis in Leydig cells. The function of Nur77 is modulated through interaction with other proteins. FOXA3, a transcription factor that is crucial for male fertility, is also expressed in Leydig cells. Here, we sought to elucidate the role of FOXA3 in testicular steroidogenesis by focusing on its interaction with Nur77. LH/cAMP signaling induces the onset of steroidogenesis in Leydig cells but has a repressive effect on the expression of FOXA3. Overexpression of FOXA3 in MA-10 Leydig cells repressed cAMP-induced expression of Nur77 and its target steroidogenic genes (StAR, P450c17, and Hsd3β). Furthermore, FOXA3 suppressed Nur77 transactivation of the promoter of steroidogenic genes. In mouse primary Leydig cells, adenovirus-mediated overexpression of FOXA3 had similar effects and resulted in decreased production of testosterone. Taken together, these results suggest the role of FOXA3 in the regulation of steroidogenic genes in Leydig cells and fine-tuning steroidogenesis in the testis.

scholarly journals Analysis of Resistance Gene-Mediated Defense Responses in Arabidopsis thaliana Plants Carrying a Mutation in CPR5

1998 ◽  
Vol 11 (12) ◽  
pp. 1196-1206 ◽  
Author(s):  
Jens Boch ◽  
Michelle L. Verbsky ◽  
Tara L. Robertson ◽  
John C. Larkin ◽  
Barbara N. Kunkel
Keyword(s):  
Gene Expression ◽  
Arabidopsis Thaliana ◽  
Resistance Gene ◽  
Pseudomonas Syringae ◽  
Bacterial Pathogen ◽  
Defense Responses ◽  
Negative Regulator ◽  
Suppressor Mutations ◽  
Defense Related Gene ◽  
Rapid Activation

In resistant plants, pathogen attack often leads to rapid activation of defense responses that limit multiplication and spread of the pathogen. To investigate the signaling mechanisms underlying this process, we carried out a screen for mutants in the signaling pathway governing resistance in Arabidopsis thaliana to the bacterial pathogen Pseudomonas syringae. This involved screening for suppressor mutations that restored resistance to a susceptible line carrying a mutation in the RPS2 resistance gene. A mutant that conferred resistance by activating defense responses in the absence of pathogens was isolated. This mutant, which carries a mutation at the CPR5 locus and was thus designated cpr5-2, exhibited resistance to P. syringae, spontaneous development of necrotic lesions, elevated PR gene expression in the absence of pathogens, and abnormal trichomes. Resistance gene-mediated defenses, including the hypersensitive response, restriction of pathogen growth, and induction of defense-related gene expression, were functional in cpr5-2 mutant plants. Additionally, in cpr5-2 plants RPS2-mediated induction of PR-1 expression was enhanced, whereas RPM1-mediated induction of ELI3 was not. These findings suggest that CPR5 encodes a negative regulator of the RPS2 signal transduc-tion pathway.

scholarly journals The BIR2/BIR3-interacting Phospholipase D gamma 1 negatively regulates immunity in Arabidopsis

2019 ◽  
Author(s):  
Maria A. Schlöffel ◽  
Andrea Salzer ◽  
Wei-Lin Wan ◽  
Ringo van Wijk ◽  
Maja Šemanjski ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Pseudomonas Syringae ◽  
Phospholipase D ◽  
Plant Immunity ◽  
Negative Regulator ◽  
Regulatory Function ◽  
Membrane Phospholipids ◽  
Effective Strategies ◽  
Pathogen Invasion ◽  
Molecular Patterns

ABSTRACTPlants have evolved effective strategies to defend themselves against pathogen invasion. Starting from the plasma membrane with the recognition of microbe-associated molecular patterns (MAMPs) via pattern recognition receptors, internal cellular signaling pathways are induced to ultimately fend off the attack. Phospholipase D (PLD) hydrolyzes membrane phospholipids to produce phosphatidic acid (PA), which has been proposed to play a second messenger role in immunity. The Arabidopsis PLD family consists of 12 members and for some a specific function in resistance towards a subset of pathogens has been shown. We demonstrate here that Arabidopsis PLDγ1, but not its close homologs PLDγ2 and PLDγ3, is specifically involved in plant immunity. Genetic inactivation of PLDγ1 resulted in increased resistance towards the virulent bacterium Pseudomonas syringae pv. tomato DC3000 and the necrotrophic fungus Botrytis cinerea. As pldγ1 mutant plants responded with elevated levels of reactive oxygen species to MAMP-treatment, a negative regulatory function for this PLD isoform is proposed. Importantly, PA levels in pldγ1 mutants were not affected compared to stressed wild-type plants, suggesting that alterations in PA levels are unlikely the cause for the enhanced immunity in the pldγ1 line. Instead, the plasma-membrane-attached PLDγ1 protein colocalized and associated with the receptor-like kinases BIR2 and BIR3, which are known negative regulators of pattern-triggered immunity. Moreover, complex formation of PLDγ1 and BIR2 was further promoted upon MAMP-treatment. Hence, we propose that PLDγ1 acts as a negative regulator of plant immune responses in complex with immunity-related proteins BIR2 and BIR3.One-sentence summaryA phospholipase D is a novel negative regulator of plant immunity and forms complexes with regulatory receptor-like kinases.

An Apple B-Box Protein MdBBX37 Modulates Anthocyanin Biosynthesis and Hypocotyl Elongation Synergistically with MdMYBs and MdHY5

2019 ◽  
Vol 61 (1) ◽  
pp. 130-143 ◽  
Author(s):  
Jian-Ping An ◽  
Xiao-Fei Wang ◽  
Richard V Espley ◽  
Kui Lin-Wang ◽  
Si-Qi Bi ◽  
...  
Keyword(s):  
Target Genes ◽  
Anthocyanin Biosynthesis ◽  
Hypocotyl Elongation ◽  
Multiple Roles ◽  
Negative Regulator ◽  
Light Signaling ◽  
Plant Growth And Development ◽  
Positive Regulators ◽  
Negative Role

Abstract As an important environment factor, light affects plant growth and development throughout life. B-BOX (BBX) proteins play key roles in the regulation of light signaling. Although the multiple roles of BBX proteins have been extensively studied in Arabidopsis, the research in apple is much less extensive. In this study, we systematically characterized the negative role of an apple BBX protein MdBBX37 in light signaling, including inhibiting anthocyanin biosynthesis and promoting hypocotyl elongation. We found that MdBBX37 interacted with MdMYB1 and MdMYB9, two key positive regulators of anthocyanin biosynthesis, and inhibited the binding of those two proteins to their target genes and, therefore, negatively regulated anthocyanin biosynthesis. In addition, MdBBX37 directly bound to the promoter of MdHY5, a positive regulator of light signaling, and suppressed its expression, and thus relieved MdHY5-mediated hypocotyl inhibition. Taken together, our investigations suggest that MdBBX37 is a negative regulator of light signaling in apple. Our study will provide reference for further study on the functions of BBX proteins in apple.

scholarly journals Role of ethylene response factors (ERFs) in fruit ripening

2020 ◽  
Vol 4 (1) ◽  
pp. 15-20 ◽  
Author(s):  
Jin Gao ◽  
Yaoxin Zhang ◽  
Zhengguo Li ◽  
Mingchun Liu
Keyword(s):  
Fruit Ripening ◽  
Defense Responses ◽  
Ethylene Response Factor ◽  
Response Factors ◽  
Climacteric Fruit ◽  
Ethylene Response ◽  
Ethylene Signalling ◽  
Ethylene Response Factors ◽  
Flower Abscission

Abstract The ethylene response factors (ERFs) belong to the APETALA2/ethylene response factor (AP2/ERF) superfamily and act downstream of the ethylene signalling pathway to regulate the expression of ethylene responsive genes. In different species, ERFs have been reported to be involved in plant development, flower abscission, fruit ripening, and defense responses. In this review, based on the new progress made by recent studies, we summarize the specific role and mode of action of ERFs in regulating different aspects of ripening in both climacteric and non-climacteric fruits, and provide new insights into the role of ethylene in non-climacteric fruit ripening.

scholarly journals Regulation of Polyhydroxybutyrate Accumulation in Sinorhizobium meliloti by the Trans-Encoded Small RNA MmgR

2017 ◽  
Vol 199 (8) ◽  
Author(s):  
Antonio Lagares ◽  
Germán Ceizel Borella ◽  
Uwe Linne ◽  
Anke Becker ◽  
Claudio Valverde
Keyword(s):  
Small Rnas ◽  
Sinorhizobium Meliloti ◽  
Reducing Power ◽  
Negative Regulator ◽  
Fine Tuning ◽  
Biological Role ◽  
Wild Type ◽  
Content Type ◽  
In The Wild

ABSTRACT Riboregulation has a major role in the fine-tuning of multiple bacterial processes. Among the RNA players, trans-encoded untranslated small RNAs (sRNAs) regulate complex metabolic networks by tuning expression from multiple target genes in response to numerous signals. In Sinorhizobium meliloti, over 400 sRNAs are expressed under different stimuli. The sRNA MmgR (standing for Makes more granules Regulator) has been of particular interest to us since its sequence and structure are highly conserved among the alphaproteobacteria and its expression is regulated by the amount and quality of the bacterium's available nitrogen source. In this work, we explored the biological role of MmgR in S. meliloti 2011 by characterizing the effect of a deletion of the internal conserved core of mmgR (mmgR Δ33–51). This mutation resulted in larger amounts of polyhydroxybutyrate (PHB) distributed into more intracellular granules than are found in the wild-type strain. This phenotype was expressed upon cessation of balanced growth owing to nitrogen depletion in the presence of surplus carbon (i.e., at a carbon/nitrogen molar ratio greater than 10). The normal PHB accumulation was complemented with a wild-type mmgR copy but not with unrelated sRNA genes. Furthermore, the expression of mmgR limited PHB accumulation in the wild type, regardless of the magnitude of the C surplus. Quantitative proteomic profiling and quantitative reverse transcription-PCR (qRT-PCR) revealed that the absence of MmgR results in a posttranscriptional overexpression of both PHB phasin proteins (PhaP1 and PhaP2). Together, our results indicate that the widely conserved alphaproteobacterial MmgR sRNA fine-tunes the regulation of PHB storage in S. meliloti. IMPORTANCE High-throughput RNA sequencing has recently uncovered an overwhelming number of trans-encoded small RNAs (sRNAs) in diverse prokaryotes. In the nitrogen-fixing alphaproteobacterial symbiont of alfalfa root nodules Sinorhizobium meliloti, only four out of hundreds of identified sRNA genes have been functionally characterized. Thus, uncovering the biological role of sRNAs currently represents a major issue and one that is particularly challenging because of the usually subtle quantitative regulation contributed by most characterized sRNAs. Here, we have characterized the function of the broadly conserved alphaproteobacterial sRNA gene mmgR in S. meliloti. Our results strongly suggest that mmgR encodes a negative regulator of the accumulation of polyhydroxybutyrate, the major carbon and reducing power storage polymer in S. meliloti cells growing under conditions of C/N overbalance.

scholarly journals Modulation of Organogenesis and Somatic Embryogenesis by Ethylene: An Overview

Plants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1208
Author(s):  
Mariana Neves ◽  
Sandra Correia ◽  
Carlos Cavaleiro ◽  
Jorge Canhoto
Keyword(s):  
Somatic Embryogenesis ◽  
Stress Responses ◽  
Ethylene Response Factor ◽  
Regeneration Capacity ◽  
Strongly Connected ◽  
High Regeneration ◽  
Hormonal Crosstalk ◽  
Erf Family ◽  
Signaling Components

Ethylene is a plant hormone controlling physiological and developmental processes such as fruit maturation, hairy root formation, and leaf abscission. Its effect on regeneration systems, such as organogenesis and somatic embryogenesis (SE), has been studied, and progress in molecular biology techniques have contributed to unveiling the mechanisms behind its effects. The influence of ethylene on regeneration should not be overlooked. This compound affects regeneration differently, depending on the species, genotype, and explant. In some species, ethylene seems to revert recalcitrance in genotypes with low regeneration capacity. However, its effect is not additive, since in genotypes with high regeneration capacity this ability decreases in the presence of ethylene precursors, suggesting that regeneration is modulated by ethylene. Several lines of evidence have shown that the role of ethylene in regeneration is markedly connected to biotic and abiotic stresses as well as to hormonal-crosstalk, in particular with key regeneration hormones and growth regulators of the auxin and cytokinin families. Transcriptional factors of the ethylene response factor (ERF) family are regulated by ethylene and strongly connected to SE induction. Thus, an evident connection between ethylene, stress responses, and regeneration capacity is markedly established. In this review the effect of ethylene and the way it interacts with other players during organogenesis and somatic embryogenesis is discussed. Further studies on the regulation of ERF gene expression induced by ethylene during regeneration can contribute to new insights on the exact role of ethylene in these processes. A possible role in epigenetic modifications should be considered, since some ethylene signaling components are directly related to histone acetylation.

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