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1.
Cell ; 161(5): 1074-1088, 2015 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-26000483

RESUMO

Microbial pathogens infect host cells by delivering virulence factors (effectors) that interfere with defenses. In plants, intracellular nucleotide-binding/leucine-rich repeat receptors (NLRs) detect specific effector interference and trigger immunity by an unknown mechanism. The Arabidopsis-interacting NLR pair, RRS1-R with RPS4, confers resistance to different pathogens, including Ralstonia solanacearum bacteria expressing the acetyltransferase effector PopP2. We show that PopP2 directly acetylates a key lysine within an additional C-terminal WRKY transcription factor domain of RRS1-R that binds DNA. This disrupts RRS1-R DNA association and activates RPS4-dependent immunity. PopP2 uses the same lysine acetylation strategy to target multiple defense-promoting WRKY transcription factors, causing loss of WRKY-DNA binding and transactivating functions needed for defense gene expression and disease resistance. Thus, RRS1-R integrates an effector target with an NLR complex at the DNA to switch a potent bacterial virulence activity into defense gene activation.


Assuntos
Arabidopsis/imunologia , Acetiltransferases/metabolismo , Arabidopsis/microbiologia , Proteínas de Arabidopsis/metabolismo , DNA/metabolismo , Modelos Moleculares , Proteínas de Plantas/metabolismo , Ralstonia solanacearum/enzimologia , Ralstonia solanacearum/metabolismo , Ralstonia solanacearum/patogenicidade , Fatores de Transcrição/metabolismo
2.
Nature ; 627(8005): 847-853, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38480885

RESUMO

Plant nucleotide-binding leucine-rich repeat (NLR) immune receptors with an N-terminal Toll/interleukin-1 receptor (TIR) domain mediate recognition of strain-specific pathogen effectors, typically via their C-terminal ligand-sensing domains1. Effector binding enables TIR-encoded enzymatic activities that are required for TIR-NLR (TNL)-mediated immunity2,3. Many truncated TNL proteins lack effector-sensing domains but retain similar enzymatic and immune activities4,5. The mechanism underlying the activation of these TIR domain proteins remain unclear. Here we show that binding of the TIR substrates NAD+ and ATP induces phase separation of TIR domain proteins in vitro. A similar condensation occurs with a TIR domain protein expressed via its native promoter in response to pathogen inoculation in planta. The formation of TIR condensates is mediated by conserved self-association interfaces and a predicted intrinsically disordered loop region of TIRs. Mutations that disrupt TIR condensates impair the cell death activity of TIR domain proteins. Our data reveal phase separation as a mechanism for the activation of TIR domain proteins and provide insight into substrate-induced autonomous activation of TIR signalling to confer plant immunity.


Assuntos
Trifosfato de Adenosina , Arabidopsis , NAD , Nicotiana , Separação de Fases , Proteínas de Plantas , Domínios Proteicos , Trifosfato de Adenosina/metabolismo , Arabidopsis/genética , Arabidopsis/imunologia , Arabidopsis/metabolismo , Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/imunologia , Proteínas de Arabidopsis/metabolismo , Morte Celular , Mutação , NAD/metabolismo , Nicotiana/genética , Nicotiana/imunologia , Nicotiana/metabolismo , Proteínas NLR/química , Proteínas NLR/genética , Proteínas NLR/imunologia , Proteínas NLR/metabolismo , Doenças das Plantas/imunologia , Imunidade Vegetal/genética , Proteínas de Plantas/química , Proteínas de Plantas/genética , Proteínas de Plantas/imunologia , Proteínas de Plantas/metabolismo , Regiões Promotoras Genéticas , Domínios Proteicos/genética , Receptores Imunológicos/química , Receptores Imunológicos/genética , Receptores Imunológicos/imunologia , Receptores Imunológicos/metabolismo , Transdução de Sinais , Receptores Toll-Like/química , Receptores de Interleucina-1/química
3.
Nature ; 598(7881): 495-499, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34497423

RESUMO

Plants deploy cell-surface and intracellular leucine rich-repeat domain (LRR) immune receptors to detect pathogens1. LRR receptor kinases and LRR receptor proteins at the plasma membrane recognize microorganism-derived molecules to elicit pattern-triggered immunity (PTI), whereas nucleotide-binding LRR proteins detect microbial effectors inside cells to confer effector-triggered immunity (ETI). Although PTI and ETI are initiated in different host cell compartments, they rely on the transcriptional activation of similar sets of genes2, suggesting pathway convergence upstream of nuclear events. Here we report that PTI triggered by the Arabidopsis LRR receptor protein RLP23 requires signalling-competent dimers of the lipase-like proteins EDS1 and PAD4, and of ADR1 family helper nucleotide-binding LRRs, which are all components of ETI. The cell-surface LRR receptor kinase SOBIR1 links RLP23 with EDS1, PAD4 and ADR1 proteins, suggesting the formation of supramolecular complexes containing PTI receptors and transducers at the inner side of the plasma membrane. We detected similar evolutionary patterns in LRR receptor protein and nucleotide-binding LRR genes across Arabidopsis accessions; overall higher levels of variation in LRR receptor proteins than in LRR receptor kinases are consistent with distinct roles of these two receptor families in plant immunity. We propose that the EDS1-PAD4-ADR1 node is a convergence point for defence signalling cascades, activated by both surface-resident and intracellular LRR receptors, in conferring pathogen immunity.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/imunologia , Hidrolases de Éster Carboxílico/metabolismo , Proteínas de Ligação a DNA/metabolismo , Imunidade Vegetal , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas de Arabidopsis/química , Hidrolases de Éster Carboxílico/química , Proteínas de Ligação a DNA/química , Domínios Proteicos , Proteínas Quinases/química , Proteínas Quinases/metabolismo , Multimerização Proteica , Proteínas Serina-Treonina Quinases/química , Receptores de Superfície Celular/química , Receptores de Superfície Celular/metabolismo
4.
N Engl J Med ; 389(25): 2341-2354, 2023 12 21.
Artigo em Inglês | MEDLINE | ID: mdl-37888913

RESUMO

BACKGROUND: The efficacy of simvastatin in critically ill patients with coronavirus disease 2019 (Covid-19) is unclear. METHODS: In an ongoing international, multifactorial, adaptive platform, randomized, controlled trial, we evaluated simvastatin (80 mg daily) as compared with no statin (control) in critically ill patients with Covid-19 who were not receiving statins at baseline. The primary outcome was respiratory and cardiovascular organ support-free days, assessed on an ordinal scale combining in-hospital death (assigned a value of -1) and days free of organ support through day 21 in survivors; the analyis used a Bayesian hierarchical ordinal model. The adaptive design included prespecified statistical stopping criteria for superiority (>99% posterior probability that the odds ratio was >1) and futility (>95% posterior probability that the odds ratio was <1.2). RESULTS: Enrollment began on October 28, 2020. On January 8, 2023, enrollment was closed on the basis of a low anticipated likelihood that prespecified stopping criteria would be met as Covid-19 cases decreased. The final analysis included 2684 critically ill patients. The median number of organ support-free days was 11 (interquartile range, -1 to 17) in the simvastatin group and 7 (interquartile range, -1 to 16) in the control group; the posterior median adjusted odds ratio was 1.15 (95% credible interval, 0.98 to 1.34) for simvastatin as compared with control, yielding a 95.9% posterior probability of superiority. At 90 days, the hazard ratio for survival was 1.12 (95% credible interval, 0.95 to 1.32), yielding a 91.9% posterior probability of superiority of simvastatin. The results of secondary analyses were consistent with those of the primary analysis. Serious adverse events, such as elevated levels of liver enzymes and creatine kinase, were reported more frequently with simvastatin than with control. CONCLUSIONS: Although recruitment was stopped because cases had decreased, among critically ill patients with Covid-19, simvastatin did not meet the prespecified criteria for superiority to control. (REMAP-CAP ClinicalTrials.gov number, NCT02735707.).


Assuntos
COVID-19 , Estado Terminal , Inibidores de Hidroximetilglutaril-CoA Redutases , Sinvastatina , Humanos , Teorema de Bayes , COVID-19/mortalidade , COVID-19/terapia , Tratamento Farmacológico da COVID-19 , Estado Terminal/mortalidade , Estado Terminal/terapia , Mortalidade Hospitalar , Inibidores de Hidroximetilglutaril-CoA Redutases/uso terapêutico , Sinvastatina/uso terapêutico , Resultado do Tratamento
5.
Proc Natl Acad Sci U S A ; 120(11): e2210406120, 2023 03 14.
Artigo em Inglês | MEDLINE | ID: mdl-36877846

RESUMO

Plant disease resistance involves both detection of microbial molecular patterns by cell-surface pattern recognition receptors and detection of pathogen effectors by intracellular NLR immune receptors. NLRs are classified as sensor NLRs, involved in effector detection, or helper NLRs required for sensor NLR signaling. TIR-domain-containing sensor NLRs (TNLs) require helper NLRs NRG1 and ADR1 for resistance, and helper NLR activation of defense requires the lipase-domain proteins EDS1, SAG101, and PAD4. Previously, we found that NRG1 associates with EDS1 and SAG101 in a TNL activation-dependent manner [X. Sun et al., Nat. Commun. 12, 3335 (2021)]. We report here how the helper NLR NRG1 associates with itself and with EDS1 and SAG101 during TNL-initiated immunity. Full immunity requires coactivation and mutual potentiation of cell-surface and intracellular immune receptor-initiated signaling [B. P. M. Ngou, H.-K. Ahn, P. Ding, J. D. G. Jones, Nature 592, 110-115 (2021), M. Yuan et al., Nature 592, 105-109 (2021)]. We find that while activation of TNLs is sufficient to promote NRG1-EDS1-SAG101 interaction, the formation of an oligomeric NRG1-EDS1-SAG101 resistosome requires the additional coactivation of cell-surface receptor-initiated defense. These data suggest that NRG1-EDS1-SAG101 resistosome formation in vivo is part of the mechanism that links intracellular and cell-surface receptor signaling pathways.


Assuntos
Resistência à Doença , Doenças das Plantas , Imunidade Vegetal , Receptores Imunológicos , Membrana Celular , Lipase , Receptores Imunológicos/genética
6.
Plant Cell ; 34(5): 1479-1496, 2022 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-35143666

RESUMO

A protein domain (Toll and Interleukin-1 receptor [TIR]-like) with homology to animal TIRs mediates immune signaling in prokaryotes and eukaryotes. Here, we present an overview of TIR evolution and the molecular versatility of TIR domains in different protein architectures for host protection against microbial attack. Plant TIR-based signaling emerges as being central to the potentiation and effectiveness of host defenses triggered by intracellular and cell-surface immune receptors. Equally relevant for plant fitness are mechanisms that limit potent TIR signaling in healthy tissues but maintain preparedness for infection. We propose that seed plants evolved a specialized protein module to selectively translate TIR enzymatic activities to defense outputs, overlaying a more general function of TIRs.


Assuntos
Imunidade Vegetal , Receptores de Interleucina-1 , Animais , Imunidade Vegetal/genética , Plantas/genética , Plantas/metabolismo , Domínios Proteicos , Receptores de Superfície Celular , Receptores de Interleucina-1/metabolismo , Transdução de Sinais
7.
Nature ; 575(7781): 109-118, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31695205

RESUMO

The current trajectory for crop yields is insufficient to nourish the world's population by 20501. Greater and more consistent crop production must be achieved against a backdrop of climatic stress that limits yields, owing to shifts in pests and pathogens, precipitation, heat-waves and other weather extremes. Here we consider the potential of plant sciences to address post-Green Revolution challenges in agriculture and explore emerging strategies for enhancing sustainable crop production and resilience in a changing climate. Accelerated crop improvement must leverage naturally evolved traits and transformative engineering driven by mechanistic understanding, to yield the resilient production systems that are needed to ensure future harvests.


Assuntos
Produção Agrícola/métodos , Produção Agrícola/estatística & dados numéricos , Produtos Agrícolas/genética , Abastecimento de Alimentos/métodos , Abastecimento de Alimentos/estatística & dados numéricos , Aquecimento Global/estatística & dados numéricos , Desenvolvimento Sustentável/tendências , Aclimatação/genética , Aclimatação/fisiologia , Animais , Produtos Agrícolas/crescimento & desenvolvimento , Produtos Agrícolas/microbiologia , Produtos Agrícolas/virologia , Fertilizantes , Humanos , Doenças das Plantas/genética , Doenças das Plantas/prevenção & controle , Doenças das Plantas/estatística & dados numéricos , Chuva
8.
Br J Haematol ; 2024 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-38772913

RESUMO

The precise link between inflammation and pathogenesis of myelodysplastic syndrome (MDS) is yet to be fully established. We developed a novel method to measure ASC/NLRP3 protein specks which are specific for the NLRP3 inflammasome only. We combined this with cytokine profiling to characterise various inflammatory markers in a large cohort of patients with lower risk MDS in comparison to healthy controls and patients with defined autoinflammatory disorders (AIDs). The ASC/NLRP3 specks were significantly elevated in MDS patients compared to healthy controls (p < 0.001) and these levels were comparable to those found in patients with AIDs. The distribution of protein specks positive only for ASC was different to ASC/NLRP3 ones suggesting that other ASC-containing inflammasome complexes might be important in the pathogenesis of MDS. Patients with MDS-SLD had the lowest levels of interleukin (IL)-1ß, tumour necrosis factor (TNF), IL-23, IL-33, interferon (IFN) γ and IFN-α2, compared to other diagnostic categories. We also found that inflammatory cytokine TNF was positively associated with MDS progression to a more aggressive form of disease and IL-6 and IL-1ß with time to first red blood cell transfusion. Our study shows that there is value in analysing inflammatory biomarkers in MDS, but their diagnostic and prognostic utility is yet to be fully validated.

9.
N Engl J Med ; 384(16): 1491-1502, 2021 04 22.
Artigo em Inglês | MEDLINE | ID: mdl-33631065

RESUMO

BACKGROUND: The efficacy of interleukin-6 receptor antagonists in critically ill patients with coronavirus disease 2019 (Covid-19) is unclear. METHODS: We evaluated tocilizumab and sarilumab in an ongoing international, multifactorial, adaptive platform trial. Adult patients with Covid-19, within 24 hours after starting organ support in the intensive care unit (ICU), were randomly assigned to receive tocilizumab (8 mg per kilogram of body weight), sarilumab (400 mg), or standard care (control). The primary outcome was respiratory and cardiovascular organ support-free days, on an ordinal scale combining in-hospital death (assigned a value of -1) and days free of organ support to day 21. The trial uses a Bayesian statistical model with predefined criteria for superiority, efficacy, equivalence, or futility. An odds ratio greater than 1 represented improved survival, more organ support-free days, or both. RESULTS: Both tocilizumab and sarilumab met the predefined criteria for efficacy. At that time, 353 patients had been assigned to tocilizumab, 48 to sarilumab, and 402 to control. The median number of organ support-free days was 10 (interquartile range, -1 to 16) in the tocilizumab group, 11 (interquartile range, 0 to 16) in the sarilumab group, and 0 (interquartile range, -1 to 15) in the control group. The median adjusted cumulative odds ratios were 1.64 (95% credible interval, 1.25 to 2.14) for tocilizumab and 1.76 (95% credible interval, 1.17 to 2.91) for sarilumab as compared with control, yielding posterior probabilities of superiority to control of more than 99.9% and of 99.5%, respectively. An analysis of 90-day survival showed improved survival in the pooled interleukin-6 receptor antagonist groups, yielding a hazard ratio for the comparison with the control group of 1.61 (95% credible interval, 1.25 to 2.08) and a posterior probability of superiority of more than 99.9%. All secondary analyses supported efficacy of these interleukin-6 receptor antagonists. CONCLUSIONS: In critically ill patients with Covid-19 receiving organ support in ICUs, treatment with the interleukin-6 receptor antagonists tocilizumab and sarilumab improved outcomes, including survival. (REMAP-CAP ClinicalTrials.gov number, NCT02735707.).


Assuntos
Anticorpos Monoclonais Humanizados/uso terapêutico , Tratamento Farmacológico da COVID-19 , Receptores de Interleucina-6/antagonistas & inibidores , Adulto , Idoso , Anticorpos Monoclonais Humanizados/efeitos adversos , COVID-19/complicações , COVID-19/mortalidade , COVID-19/terapia , Estado Terminal , Feminino , Mortalidade Hospitalar , Humanos , Unidades de Terapia Intensiva , Masculino , Pessoa de Meia-Idade , Razão de Chances , Respiração Artificial
10.
Plant Physiol ; 191(1): 161-176, 2023 01 02.
Artigo em Inglês | MEDLINE | ID: mdl-36259930

RESUMO

In Nicotiana benthamiana, the expression of the Xanthomonas effector XANTHOMONAS OUTER PROTEIN Q (XopQ) triggers RECOGNITION OF XOPQ1 (ROQ1)-dependent effector-triggered immunity (ETI) responses accompanied by the accumulation of plastids around the nucleus and the formation of stromules. Both plastid clustering and stromules were proposed to contribute to ETI-related hypersensitive cell death and thereby to plant immunity. Whether these reactions are directly connected to ETI signaling events has not been tested. Here, we utilized transient expression experiments to determine whether XopQ-triggered plastid reactions are a result of XopQ perception by the immune receptor ROQ1 or a consequence of XopQ virulence activity. We found that N. benthamiana mutants lacking ROQ1, ENHANCED DISEASE SUSCEPTIBILITY 1, or the helper NUCLEOTIDE-BINDING LEUCINE-RICH REPEAT IMMUNE RECEPTORS (NLRs) N-REQUIRED GENE 1 (NRG1) and ACTIVATED DISEASE RESISTANCE GENE 1 (ADR1), fail to elicit XopQ-dependent host cell death and stromule formation. Mutants lacking only NRG1 lost XopQ-dependent cell death but retained some stromule induction that was abolished in the nrg1_adr1 double mutant. This analysis aligns XopQ-triggered stromules with the ETI signaling cascade but not to host programmed cell death. Furthermore, data reveal that XopQ-triggered plastid clustering is not strictly linked to stromule formation during ETI. Our data suggest that stromule formation, in contrast to chloroplast perinuclear dynamics, is an integral part of the N. benthamiana ETI response and that both NRG1 and ADR1 hNLRs play a role in this ETI response.


Assuntos
Xanthomonas , Xanthomonas/metabolismo , Nicotiana/genética , Nicotiana/metabolismo , Proteínas/metabolismo , Plastídeos , Cloroplastos , Imunidade Vegetal/genética , Doenças das Plantas/genética
11.
Plant Physiol ; 191(1): 626-642, 2023 01 02.
Artigo em Inglês | MEDLINE | ID: mdl-36227084

RESUMO

Toll/Interleukin-1 receptor (TIR) domains are integral to immune systems across all kingdoms. In plants, TIRs are present in nucleotide-binding leucine-rich repeat (NLR) immune receptors, NLR-like, and TIR-only proteins. Although TIR-NLR and TIR signaling in plants require the ENHANCED DISEASE SUSCEPTIBILITY 1 (EDS1) protein family, TIRs persist in species that have no EDS1 members. To assess whether particular TIR groups evolved with EDS1, we searched for TIR-EDS1 co-occurrence patterns. Using a large-scale phylogenetic analysis of TIR domains from 39 algal and land plant species, we identified 4 TIR families that are shared by several plant orders. One group occurred in TIR-NLRs of eudicots and another in TIR-NLRs across eudicots and magnoliids. Two further groups were more widespread. A conserved TIR-only group co-occurred with EDS1 and members of this group elicit EDS1-dependent cell death. In contrast, a maize (Zea mays) representative of TIR proteins with tetratricopeptide repeats was also present in species without EDS1 and induced EDS1-independent cell death. Our data provide a phylogeny-based plant TIR classification and identify TIRs that appear to have evolved with and are dependent on EDS1, while others have EDS1-independent activity.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Proteínas de Ligação a DNA , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Suscetibilidade a Doenças , Proteínas de Ligação a DNA/metabolismo , Filogenia , Doenças das Plantas/genética , Imunidade Vegetal/fisiologia
12.
J Exp Bot ; 75(5): 1530-1546, 2024 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-37976211

RESUMO

Arabidopsis PHYTOALEXIN DEFICIENT 4 (PAD4) has an essential role in pathogen resistance as a heterodimer with ENHANCED DISEASE SUSCEPTIBILITY 1 (EDS1). Here we investigated an additional PAD4 role in which it associates with and promotes the maturation of the immune-related cysteine protease RESPONSIVE TO DEHYDRATION 19 (RD19). We found that RD19 and its paralog RD19c promoted EDS1- and PAD4-mediated effector-triggered immunity to an avirulent Pseudomonas syringae strain, DC3000, expressing the effector AvrRps4 and basal immunity against the fungal pathogen Golovinomyces cichoracearum. Overexpression of RD19, but not RD19 protease-inactive catalytic mutants, in Arabidopsis transgenic lines caused EDS1- and PAD4-dependent autoimmunity and enhanced pathogen resistance. In these lines, RD19 maturation to a pro-form required its catalytic residues, suggesting that RD19 undergoes auto-processing. In transient assays, PAD4 interacted preferentially with the RD19 pro-protease and promoted its nuclear accumulation in leaf cells. Our results lead us to propose a model for PAD4-stimulated defense potentiation. PAD4 promotes maturation and nuclear accumulation of processed RD19, and RD19 then stimulates EDS1-PAD4 dimer activity to confer pathogen resistance. This study highlights potentially important additional PAD4 functions that eventually converge on canonical EDS1-PAD4 dimer signaling in plant immunity.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Cisteína Proteases , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/química , Hidrolases de Éster Carboxílico/química , Cisteína Proteases/genética , Fitoalexinas , Doenças das Plantas/microbiologia , Imunidade Vegetal/genética
13.
Plant Cell ; 33(6): 2015-2031, 2021 07 19.
Artigo em Inglês | MEDLINE | ID: mdl-33751120

RESUMO

Acquisition of nutrients from different species is necessary for pathogen colonization. Iron is an essential mineral nutrient for nearly all organisms, but little is known about how pathogens manipulate plant hosts to acquire iron. Here, we report that AvrRps4, an effector protein delivered by Pseudomonas syringae bacteria to plants, interacts with and targets the plant iron sensor protein BRUTUS (BTS) to facilitate iron uptake and pathogen proliferation in Arabidopsis thaliana. Infection of rps4 and eds1 by P. syringae pv. tomato (Pst) DC3000 expressing AvrRps4 resulted in iron accumulation, especially in the plant apoplast. AvrRps4 alleviates BTS-mediated degradation of bHLH115 and ILR3(IAA-Leucine resistant 3), two iron regulatory proteins. In addition, BTS is important for accumulating immune proteins Enhanced Disease Susceptibility1 (EDS1) at both the transcriptional and protein levels upon Pst (avrRps4) infections. Our findings suggest that AvrRps4 targets BTS to facilitate iron accumulation and BTS contributes to RPS4/EDS1-mediated immune responses.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/fisiologia , Proteínas de Bactérias/metabolismo , Interações Hospedeiro-Patógeno/fisiologia , Ferro/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/imunologia , Proteínas de Bactérias/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/imunologia , Proteínas de Ligação a DNA/metabolismo , Regulação da Expressão Gênica de Plantas , Mutação , Imunidade Vegetal/genética , Plantas Geneticamente Modificadas , Pseudomonas syringae/metabolismo , Pseudomonas syringae/patogenicidade , Ubiquitina-Proteína Ligases/genética
14.
PLoS Genet ; 17(1): e1009290, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33493201

RESUMO

Temperature impacts plant immunity and growth but how temperature intersects with endogenous pathways to shape natural variation remains unclear. Here we uncover variation between Arabidopsis thaliana natural accessions in response to two non-stress temperatures (22°C and 16°C) affecting accumulation of the thermoresponsive stress hormone salicylic acid (SA) and plant growth. Analysis of differentially responding A. thaliana accessions shows that pre-existing SA provides a benefit in limiting infection by Pseudomonas syringae pathovar tomato DC3000 bacteria at both temperatures. Several A. thaliana genotypes display a capacity to mitigate negative effects of high SA on growth, indicating within-species plasticity in SA-growth tradeoffs. An association study of temperature x SA variation, followed by physiological and immunity phenotyping of mutant and over-expression lines, identifies the transcription factor bHLH059 as a temperature-responsive SA immunity regulator. Here we reveal previously untapped diversity in plant responses to temperature and a way forward in understanding the genetic architecture of plant adaptation to changing environments.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Imunidade Vegetal/genética , Sensação Térmica/genética , Arabidopsis/imunologia , Arabidopsis/fisiologia , Proteínas de Arabidopsis/imunologia , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Doenças das Plantas/genética , Doenças das Plantas/imunologia , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Pseudomonas syringae/genética , Ácido Salicílico/metabolismo , Transdução de Sinais/efeitos dos fármacos , Temperatura , Sensação Térmica/imunologia , Fatores de Transcrição/genética
15.
J Sci Food Agric ; 2024 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-38661233

RESUMO

BACKGROUND: Wheat distillers' grains (WDG) and seaweeds are recommended as alternative protein sources and enteric methane mitigators in dairy cow diets, respectively, but little is known about their impact on milk quality and safety. In the present study, 16 cows in four 4 × 4 Latin squares were fed isonitrogenous diets (50:50 forage:concentrate ratio), with rapeseed meal (RSM)-based or WDG-based concentrate (230 and 205 g kg-1 dry matter) and supplemented with or without Saccharina latissima. RESULTS: Replacement of RSM with WDG enhanced milk nutritional profile by decreasing milk atherogenicity (P = 0.002) and thrombogenicity (P = 0.019) indices and the concentrations of the nutritionally undesirable saturated fatty acids - specifically, lauric (P = 0.045), myristic (P = 0.022) and palmitic (P = 0.007) acids. It also increased milk concentrations of the nutritionally beneficial vaccenic (P < 0.001), oleic (P = 0.030), linoleic (P < 0.001), rumenic (P < 0.001) and α-linolenic (P = 0.012) acids, and total monounsaturated (P = 0.044), polyunsaturated (P < 0.001) and n-6 (P < 0.001) fatty acids. Feeding Saccharina latissima at 35.7 g per cow per day did not affect the nutritionally relevant milk fatty acids or pose any risk on milk safety, as bromoform concentrations in milk were negligible and unaffected by the dietary treatments. However, it slightly reduced milk concentrations of pantothenate. CONCLUSION: Feeding WDG to dairy cows improved milk fatty acid profiles, by increasing the concentrations of nutritionally beneficial fatty acids and reducing the concentration of nutritionally undesirable saturated fatty acids, while feeding seaweed slightly reduced pantothenate concentrations. However, when considering the current average milk intakes in the population, the milk compositional differences between treatments in this study appear relatively small to have an effect on human health. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

16.
Plant J ; 110(5): 1415-1432, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35324052

RESUMO

Arabidopsis pathogen effector-triggered immunity (ETI) is controlled by a family of three lipase-like proteins (EDS1, PAD4, and SAG101) and two subfamilies of HET-S/LOB-B (HeLo)-domain "helper" nucleotide-binding/leucine-rich repeats (ADR1s and NRG1s). EDS1-PAD4 dimers cooperate with ADR1s, and EDS1-SAG101 dimers with NRG1s, in two separate defense-promoting modules. EDS1-PAD4-ADR1 and EDS1-SAG101-NRG1 complexes were detected in immune-activated leaf extracts but the molecular determinants for specific complex formation and function remain unknown. EDS1 signaling is mediated by a C-terminal EP domain (EPD) surface surrounding a cavity formed by the heterodimer. Here we investigated whether the EPDs of PAD4 and SAG101 contribute to EDS1 dimer functions. Using a structure-guided approach, we undertook a comprehensive mutational analysis of Arabidopsis PAD4. We identify two conserved residues (Arg314 and Lys380) lining the PAD4 EPD cavity that are essential for EDS1-PAD4-mediated pathogen resistance, but are dispensable for the PAD4-mediated restriction of green peach aphid infestation. Positionally equivalent Met304 and Arg373 at the SAG101 EPD cavity are required for EDS1-SAG101 promotion of ETI-related cell death. In a PAD4 and SAG101 interactome analysis of ETI-activated tissues, PAD4R314A and SAG101M304R EPD variants maintain interaction with EDS1 but lose association, respectively, with helper nucleotide-binding/leucine-rich repeats ADR1-L1 and NRG1.1, and other immune-related proteins. Our data reveal a fundamental contribution of similar but non-identical PAD4 and SAG101 EPD surfaces to specific EDS1 dimer protein interactions and pathogen immunity.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/metabolismo , Proteínas de Arabidopsis/química , Hidrolases de Éster Carboxílico/genética , Hidrolases de Éster Carboxílico/metabolismo , Proteínas de Ligação a DNA/metabolismo , Leucina/metabolismo , Nucleotídeos/metabolismo , Doenças das Plantas , Imunidade Vegetal/genética
17.
Mol Plant Microbe Interact ; 36(8): 468-475, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37697447

RESUMO

While working for the United States Department of Agriculture on the North Dakota Agricultural College campus in Fargo, North Dakota, in the 1940s and 1950s, Harold H. Flor formulated the genetic principles for coevolving plant host-pathogen interactions that govern disease resistance or susceptibility. His 'gene-for-gene' legacy runs deep in modern plant pathology and continues to inform molecular models of plant immune recognition and signaling. In this review, we discuss recent biochemical insights to plant immunity conferred by nucleotide-binding domain/leucine-rich-repeat (NLR) receptors, which are major gene-for-gene resistance determinants in nature and cultivated crops. Structural and biochemical analyses of pathogen-activated NLR oligomers (resistosomes) reveal how different NLR subtypes converge in various ways on calcium (Ca2+) signaling to promote pathogen immunity and host cell death. Especially striking is the identification of nucleotide-based signals generated enzymatically by plant toll-interleukin 1 receptor (TIR) domain NLRs. These small molecules are part of an emerging family of TIR-produced cyclic and noncyclic nucleotide signals that steer immune and cell-death responses in bacteria, mammals, and plants. A combined genetic, molecular, and biochemical understanding of plant NLR activation and signaling provides exciting new opportunities for combatting diseases in crops. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.


Assuntos
Agricultura , Produtos Agrícolas , Estados Unidos , Animais , Produtos Agrícolas/genética , Cálcio , Morte Celular , Nucleotídeos , Mamíferos
18.
New Phytol ; 239(4): 1404-1419, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37306028

RESUMO

Transcriptional corepressors of the Topless (TPL) family regulate plant hormone and immunity signaling. The lack of a genome-wide profile of their chromatin associations limits understanding of the TPL family roles in transcriptional regulation. Chromatin immunoprecipitation with sequencing (ChIP-Seq) was performed on Arabidopsis thaliana lines expressing GFP-tagged Topless-related 1 (TPR1-GFP) with and without constitutive immunity via Enhanced Disease Susceptibility 1 (EDS1). RNA-Seq profiling of the TPR1-GFP lines and pathogen-infected tpl/tpr mutants, combined with measuring immunity, growth, and physiological parameters was employed to investigate TPL/TPR roles in immunity and defense homeostasis. TPR1 was enriched at promoter regions of c. 1400 genes and c. 10% of the detected binding required EDS1 immunity signaling. In a tpr1 tpl tpr4 (t3) mutant, resistance to bacteria was slightly compromised, and defense-related transcriptional reprogramming was weakly reduced or enhanced, respectively, at early (< 1 h) and late 24 h stages of bacterial infection. The t3 plants challenged with bacteria or pathogen-associated molecular pattern nlp24 displayed photosystem II dysfunctions. Also, t3 plants were hypersensitive to phytocytokine pep1 at the level of root growth inhibition. Transgenic expression of TPR1 rescued these t3 physiological defects. We propose that TPR1 and TPL family proteins function in Arabidopsis to reduce detrimental effects associated with activated transcriptional immunity.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Regulação da Expressão Gênica de Plantas , Reguladores de Crescimento de Plantas/metabolismo , Imunidade Vegetal , Fatores de Transcrição/metabolismo
19.
JAMA ; 329(1): 39-51, 2023 01 03.
Artigo em Inglês | MEDLINE | ID: mdl-36525245

RESUMO

Importance: The longer-term effects of therapies for the treatment of critically ill patients with COVID-19 are unknown. Objective: To determine the effect of multiple interventions for critically ill adults with COVID-19 on longer-term outcomes. Design, Setting, and Participants: Prespecified secondary analysis of an ongoing adaptive platform trial (REMAP-CAP) testing interventions within multiple therapeutic domains in which 4869 critically ill adult patients with COVID-19 were enrolled between March 9, 2020, and June 22, 2021, from 197 sites in 14 countries. The final 180-day follow-up was completed on March 2, 2022. Interventions: Patients were randomized to receive 1 or more interventions within 6 treatment domains: immune modulators (n = 2274), convalescent plasma (n = 2011), antiplatelet therapy (n = 1557), anticoagulation (n = 1033), antivirals (n = 726), and corticosteroids (n = 401). Main Outcomes and Measures: The main outcome was survival through day 180, analyzed using a bayesian piecewise exponential model. A hazard ratio (HR) less than 1 represented improved survival (superiority), while an HR greater than 1 represented worsened survival (harm); futility was represented by a relative improvement less than 20% in outcome, shown by an HR greater than 0.83. Results: Among 4869 randomized patients (mean age, 59.3 years; 1537 [32.1%] women), 4107 (84.3%) had known vital status and 2590 (63.1%) were alive at day 180. IL-6 receptor antagonists had a greater than 99.9% probability of improving 6-month survival (adjusted HR, 0.74 [95% credible interval {CrI}, 0.61-0.90]) and antiplatelet agents had a 95% probability of improving 6-month survival (adjusted HR, 0.85 [95% CrI, 0.71-1.03]) compared with the control, while the probability of trial-defined statistical futility (HR >0.83) was high for therapeutic anticoagulation (99.9%; HR, 1.13 [95% CrI, 0.93-1.42]), convalescent plasma (99.2%; HR, 0.99 [95% CrI, 0.86-1.14]), and lopinavir-ritonavir (96.6%; HR, 1.06 [95% CrI, 0.82-1.38]) and the probabilities of harm from hydroxychloroquine (96.9%; HR, 1.51 [95% CrI, 0.98-2.29]) and the combination of lopinavir-ritonavir and hydroxychloroquine (96.8%; HR, 1.61 [95% CrI, 0.97-2.67]) were high. The corticosteroid domain was stopped early prior to reaching a predefined statistical trigger; there was a 57.1% to 61.6% probability of improving 6-month survival across varying hydrocortisone dosing strategies. Conclusions and Relevance: Among critically ill patients with COVID-19 randomized to receive 1 or more therapeutic interventions, treatment with an IL-6 receptor antagonist had a greater than 99.9% probability of improved 180-day mortality compared with patients randomized to the control, and treatment with an antiplatelet had a 95.0% probability of improved 180-day mortality compared with patients randomized to the control. Overall, when considered with previously reported short-term results, the findings indicate that initial in-hospital treatment effects were consistent for most therapies through 6 months.


Assuntos
COVID-19 , Adulto , Humanos , Feminino , Pessoa de Meia-Idade , Masculino , Lopinavir/uso terapêutico , Ritonavir/uso terapêutico , Seguimentos , Hidroxicloroquina/uso terapêutico , SARS-CoV-2 , Estado Terminal/terapia , Teorema de Bayes , Soroterapia para COVID-19 , Corticosteroides/uso terapêutico , Anticoagulantes/efeitos adversos , Receptores de Interleucina-6
20.
Compr Rev Food Sci Food Saf ; 22(1): 233-259, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36398756

RESUMO

Alcohol-free beers have gained popularity in the last few decades because they provide a healthier alternative to alcoholic beers and can be more widely consumed. Consumers are becoming more aware of the benefits of reducing their alcohol consumption, and this has increased the sales of nonalcoholic alternatives. However, there are still many challenges for the brewing industry to produce an alcohol-free beer that resembles the pleasant fruity flavor and overall sensory experience of regular beers. The aim of this review is to give a comprehensive overview of alcohol-free beer focusing on aroma chemistry. The formation of the most important aroma compounds, such as Strecker aldehydes, higher alcohols, and esters, is reviewed, aiming to outline the gaps in current knowledge. The role of ethanol as a direct and indirect flavor-active compound is examined separately. In parallel, the influence of the most common methods to reduce alcohol content, such as physical (dealcoholization) or biological, on the organoleptic characteristics and consumer perception of the final product, is discussed.


Assuntos
Cerveja , Odorantes , Cerveja/análise , Odorantes/análise , Etanol/análise , Bebidas , Aldeídos/análise
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