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1.
Mol Plant Pathol ; 25(5): e13464, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38695733

RESUMO

Many plant pathogens secrete effector proteins into the host plant to suppress host immunity and facilitate pathogen colonization. The necrotrophic pathogen Sclerotinia sclerotiorum causes severe plant diseases and results in enormous economic losses, in which secreted proteins play a crucial role. SsCVNH was previously reported as a secreted protein, and its expression is significantly upregulated at 3 h after inoculation on the host plant. Here, we further demonstrated that deletion of SsCVNH leads to attenuated virulence. Heterologous expression of SsCVNH in Arabidopsis enhanced pathogen infection, inhibited the host PAMP-triggered immunity (PTI) response and increased plant susceptibility to S. sclerotiorum. SsCVNH interacted with class III peroxidase AtPRX71, a positive regulator of innate immunity against plant pathogens. SsCVNH could also interact with other class III peroxidases, thus reducing peroxidase activity and suppressing plant immunity. Our results reveal a new infection strategy employed by S. sclerotiorum in which the fungus suppresses the function of class III peroxidases, the major component of PTI to promote its own infection.


Assuntos
Arabidopsis , Ascomicetos , Proteínas Fúngicas , Doenças das Plantas , Imunidade Vegetal , Ascomicetos/patogenicidade , Doenças das Plantas/microbiologia , Virulência , Arabidopsis/microbiologia , Arabidopsis/imunologia , Imunidade Vegetal/genética , Proteínas Fúngicas/metabolismo , Proteínas Fúngicas/genética , Peroxidases/metabolismo , Peroxidases/genética
2.
Nat Commun ; 15(1): 3762, 2024 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-38704378

RESUMO

Plants initiate specific defense responses by recognizing conserved epitope peptides within the flagellin proteins derived from bacteria. Proteolytic cleavage of epitope peptides from flagellin by plant apoplastic proteases is thought to be crucial for the perception of the epitope by the plant receptor. However, the identity of the plant proteases involved in this process remains unknown. Here, we establish an efficient identification system for the target proteases in Arabidopsis apoplastic fluid; the method employs native two-dimensional electrophoresis followed by an in-gel proteolytic assay using a fluorescence-quenching peptide substrate. We designed a substrate to specifically detect proteolytic activity at the C-terminus of the flg22 epitope in flagellin and identified two plant subtilases, SBT5.2 and SBT1.7, as specific proteases responsible for the C-terminal cleavage of flg22. In the apoplastic fluid of Arabidopsis mutant plants deficient in these two proteases, we observe a decrease in the C-terminal cleavage of the flg22 domain from flagellin, leading to a decrease in the efficiency of flg22 epitope liberation. Consequently, defensive reactive oxygen species (ROS) production is delayed in sbt5.2 sbt1.7 double-mutant leaf disks compared to wild type following flagellin exposure.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Epitopos , Flagelina , Espécies Reativas de Oxigênio , Flagelina/metabolismo , Flagelina/imunologia , Arabidopsis/imunologia , Arabidopsis/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/imunologia , Epitopos/imunologia , Epitopos/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Subtilisinas/metabolismo , Subtilisinas/genética , Proteólise , Mutação
3.
Cell Rep ; 43(4): 113985, 2024 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-38517890

RESUMO

Emerging evidence suggests a beneficial role of rhizobacteria in ameliorating plant disease resistance in an environment-friendly way. In this study, we characterize a rhizobacterium, Bacillus cereus NJ01, that enhances bacterial pathogen resistance in rice and Arabidopsis. Transcriptome analyses show that root inoculation of NJ01 induces the expression of salicylic acid (SA)- and abscisic acid (ABA)-related genes in Arabidopsis leaves. Genetic evidence showed that EDS1, PAD4, and WRKY18 are required for B. cereus NJ01-induced bacterial resistance. An EDS1-PAD4 complex interacts with WRKY18 and enhances its DNA binding activity. WRKY18 directly binds to the W box in the promoter region of the SA biosynthesis gene ICS1 and ABA biosynthesis genes NCED3 and NCED5 and contributes to the NJ01-induced bacterial resistance. Taken together, our findings indicate a role of the EDS1/PAD4-WRKY18 complex in rhizobacteria-induced disease resistance.


Assuntos
Ácido Abscísico , Proteínas de Arabidopsis , Arabidopsis , Bacillus cereus , Proteínas de Ligação a DNA , Doenças das Plantas , Ácido Salicílico , Bacillus cereus/genética , Ácido Abscísico/metabolismo , Arabidopsis/imunologia , Arabidopsis/microbiologia , Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Doenças das Plantas/microbiologia , Doenças das Plantas/imunologia , Proteínas de Ligação a DNA/metabolismo , Proteínas de Ligação a DNA/genética , Ácido Salicílico/metabolismo , Regulação da Expressão Gênica de Plantas , Fatores de Transcrição/metabolismo , Fatores de Transcrição/genética , Oryza/microbiologia , Oryza/imunologia , Oryza/genética , Resistência à Doença/genética , Resistência à Doença/imunologia , Imunidade Vegetal
4.
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
5.
New Phytol ; 242(5): 2163-2179, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38532564

RESUMO

The S-domain-type receptor-like kinase (SD-RLK) LIPOOLIGOSACCHARIDE-SPECIFIC REDUCED ELICITATION (LORE) from Arabidopsis thaliana is a pattern recognition receptor that senses medium-chain 3-hydroxy fatty acids, such as 3-hydroxydecanoic acid (3-OH-C10:0), to activate pattern-triggered immunity. Here, we show that LORE homomerization is required to activate 3-OH-C10:0-induced immune signaling. Fluorescence lifetime imaging in Nicotiana benthamiana demonstrates that AtLORE homomerizes via the extracellular and transmembrane domains. Co-expression of AtLORE truncations lacking the intracellular domain exerts a dominant negative effect on AtLORE signaling in both N. benthamiana and A. thaliana, highlighting that homomerization is essential for signaling. Screening for 3-OH-C10:0-induced reactive oxygen species production revealed natural variation within the Arabidopsis genus. Arabidopsis lyrata and Arabidopsis halleri do not respond to 3-OH-C10:0, although both possess a putative LORE ortholog. Both LORE orthologs have defective extracellular domains that bind 3-OH-C10:0 to a similar level as AtLORE, but lack the ability to homomerize. Thus, ligand binding is independent of LORE homomerization. Analysis of AtLORE and AlyrLORE chimera suggests that the loss of AlyrLORE homomerization is caused by several amino acid polymorphisms across the extracellular domain. Our findings shed light on the activation mechanism of LORE and the loss of 3-OH-C10:0 perception within the Arabidopsis genus.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Nicotiana , Multimerização Proteica , Transdução de Sinais , Arabidopsis/imunologia , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/química , Nicotiana/genética , Nicotiana/imunologia , Nicotiana/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Imunidade Vegetal/efeitos dos fármacos , Domínios Proteicos , Receptores de Reconhecimento de Padrão/metabolismo , Ácidos Decanoicos/metabolismo , Ácidos Decanoicos/farmacologia
6.
Nature ; 627(8003): 382-388, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38418878

RESUMO

Calcium (Ca2+) is an essential nutrient for plants and a cellular signal, but excessive levels can be toxic and inhibit growth1,2. To thrive in dynamic environments, plants must monitor and maintain cytosolic Ca2+ homeostasis by regulating numerous Ca2+ transporters3. Here we report two signalling pathways in Arabidopsis thaliana that converge on the activation of vacuolar Ca2+/H+ exchangers (CAXs) to scavenge excess cytosolic Ca2+ in plants. One mechanism, activated in response to an elevated external Ca2+ level, entails calcineurin B-like (CBL) Ca2+ sensors and CBL-interacting protein kinases (CIPKs), which activate CAXs by phosphorylating a serine (S) cluster in the auto-inhibitory domain. The second pathway, triggered by molecular patterns associated with microorganisms, engages the immune receptor complex FLS2-BAK1 and the associated cytoplasmic kinases BIK1 and PBL1, which phosphorylate the same S-cluster in CAXs to modulate Ca2+ signals in immunity. These Ca2+-dependent (CBL-CIPK) and Ca2+-independent (FLS2-BAK1-BIK1/PBL1) mechanisms combine to balance plant growth and immunity by regulating cytosolic Ca2+ homeostasis.


Assuntos
Arabidopsis , Cálcio , Homeostase , Imunidade Vegetal , Arabidopsis/citologia , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/imunologia , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Cálcio/metabolismo , Proteínas de Ligação ao Cálcio/metabolismo , Citosol/metabolismo , Fosforilação , Fosfosserina/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas de Transporte de Cátions/metabolismo , Antiporters/metabolismo
7.
Int J Mol Sci ; 25(4)2024 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-38397062

RESUMO

The ubiquitin/26S proteasome system is a crucial regulatory mechanism that governs various cellular processes in plants, including signal transduction, transcriptional regulation, and responses to biotic and abiotic stressors. Our study shows that the RING-H2-type E3 ubiquitin ligase, Arabidopsis Tóxicos en Levadura 2 (ATL2), is involved in response to fungal pathogen infection. Under normal growth conditions, the expression of the ATL2 gene is low, but it is rapidly and significantly induced by exogenous chitin. Additionally, ATL2 protein stability is markedly increased via chitin treatment, and its degradation is prolonged when 26S proteasomal function is inhibited. We found that an atl2 null mutant exhibited higher susceptibility to Alternaria brassicicola, while plants overexpressing ATL2 displayed increased resistance. We also observed that the hyphae of A. brassicicola were strongly stained with trypan blue staining, and the expression of A. brassicicola Cutinase A (AbCutA) was dramatically increased in atl2. In contrast, the hyphae were weakly stained, and AbCutA expression was significantly reduced in ATL2-overexpressing plants. Using bioinformatics, live-cell confocal imaging, and cell fractionation analysis, we revealed that ATL2 is localized to the plasma membrane. Further, it is demonstrated that the ATL2 protein possesses E3 ubiquitin ligase activity and found that cysteine 138 residue is critical for its function. Moreover, ATL2 is necessary to successfully defend against the A. brassicicola fungal pathogen. Altogether, our data suggest that ATL2 is a plasma membrane-integrated protein with RING-H2-type E3 ubiquitin ligase activity and is essential for the defense response against fungal pathogens in Arabidopsis.


Assuntos
Alternaria , Proteínas de Arabidopsis , Arabidopsis , Imunidade Vegetal , Alternaria/imunologia , Arabidopsis/imunologia , Arabidopsis/microbiologia , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Quitina/metabolismo , Regulação da Expressão Gênica de Plantas , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo
8.
Plant Cell ; 36(5): 2021-2040, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38309956

RESUMO

Calcium-dependent protein kinases (CPKs) can decode and translate intracellular calcium signals to induce plant immunity. Mutation of the exocyst subunit gene EXO70B1 causes autoimmunity that depends on CPK5 and the Toll/interleukin-1 receptor (TIR) domain resistance protein TIR-NBS2 (TN2), where direct interaction with TN2 stabilizes CPK5 kinase activity. However, how the CPK5-TN2 interaction initiates downstream immune responses remains unclear. Here, we show that, besides CPK5 activity, the physical interaction between CPK5 and functional TN2 triggers immune activation in exo70B1 and may represent reciprocal regulation between CPK5 and the TIR domain functions of TN2 in Arabidopsis (Arabidopsis thaliana). Moreover, we detected differential phosphorylation of the calmodulin-binding transcription activator 3 (CAMTA3) in the cpk5 background. CPK5 directly phosphorylates CAMTA3 at S964, contributing to its destabilization. The gain-of-function CAMTA3A855V variant that resists CPK5-induced degradation rescues immunity activated through CPK5 overexpression or exo70B1 mutation. Thus, CPK5-mediated immunity is executed through CAMTA3 repressor degradation via phosphorylation-induced and/or calmodulin-regulated processes. Conversely, autoimmunity in camta3 also partially requires functional CPK5. While the TIR domain activity of TN2 remains to be tested, our study uncovers a TN2-CPK5-CAMTA3 signaling module for exo70B1-mediated autoimmunity, highlighting the direct embedding of a calcium-sensing decoder element within resistance signalosomes.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Mutação , Imunidade Vegetal , Fatores de Transcrição , Arabidopsis/genética , Arabidopsis/imunologia , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Autoimunidade/genética , Proteínas Quinases Dependentes de Cálcio-Calmodulina/metabolismo , Proteínas Quinases Dependentes de Cálcio-Calmodulina/genética , Regulação da Expressão Gênica de Plantas , Mutação/genética , Fosforilação , Imunidade Vegetal/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
9.
Plant Physiol ; 195(1): 832-849, 2024 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-38306630

RESUMO

Plant innate immunity mediated by the nucleotide-binding leucine-rich repeat (NLR) class of immune receptors plays an important role in defense against various pathogens. Although key biochemical events involving NLR activation and signaling have been recently uncovered, we know very little about the transcriptional regulation of NLRs and their downstream signaling components. Here, we show that the Toll-Interleukin 1 receptor homology domain containing NLR (TNL) gene N (Necrosis), which confers resistance to Tobacco mosaic virus, is transcriptionally induced upon immune activation. We identified two conserved transcription factors, N required C3H zinc finger 1 (NRZ1) and N required MYB-like transcription factor 1 (NRM1), that activate N in an immune responsive manner. Genetic analyses indicated that NRZ1 and NRM1 positively regulate coiled-coil domain-containing NLR- and TNL-mediated immunity and function independently of the signaling component Enhanced Disease Susceptibility 1. Furthermore, NRZ1 functions upstream of NRM1 in cell death signaling, and their gene overexpression induces ectopic cell death and expression of NLR signaling components. Our findings uncovered a conserved transcriptional regulatory network that is central to NLR-mediated cell death and immune signaling in plants.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Regulação da Expressão Gênica de Plantas , Proteínas NLR , Imunidade Vegetal , Fatores de Transcrição , Imunidade Vegetal/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Arabidopsis/genética , Arabidopsis/imunologia , Proteínas NLR/genética , Proteínas NLR/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Transdução de Sinais/genética , Doenças das Plantas/virologia , Doenças das Plantas/imunologia , Doenças das Plantas/genética , Morte Celular
10.
Science ; 383(6684): eadk3468, 2024 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-38359131

RESUMO

Plant intracellular nucleotide-binding leucine-rich repeat receptors (NLRs) analyzed to date oligomerize and form resistosomes upon activation to initiate immune responses. Some NLRs are encoded in tightly linked co-regulated head-to-head genes whose products function together as pairs. We uncover the oligomerization requirements for different Arabidopsis paired CHS3-CSA1 alleles. These pairs form resting-state heterodimers that oligomerize into complexes distinct from NLRs analyzed previously. Oligomerization requires both conserved and allele-specific features of the respective CHS3 and CSA1 Toll-like interleukin-1 receptor (TIR) domains. The receptor kinases BAK1 and BIRs inhibit CHS3-CSA1 pair oligomerization to maintain the CHS3-CSA1 heterodimer in an inactive state. Our study reveals that paired NLRs hetero-oligomerize and likely form a distinctive "dimer of heterodimers" and that structural heterogeneity is expected even among alleles of closely related paired NLRs.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Quitina Sintase , Proteínas NLR , Doenças das Plantas , Imunidade Vegetal , Receptores Imunológicos , Alelos , Arabidopsis/genética , Arabidopsis/imunologia , Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Quitina Sintase/química , Quitina Sintase/genética , Quitina Sintase/metabolismo , Mutação , Proteínas NLR/química , Proteínas NLR/genética , Proteínas NLR/metabolismo , Doenças das Plantas/genética , Doenças das Plantas/imunologia , Imunidade Vegetal/genética , Receptores Imunológicos/química , Receptores Imunológicos/genética , Receptores Imunológicos/metabolismo , Multimerização Proteica
11.
Nature ; 625(7996): 750-759, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38200311

RESUMO

Iron is critical during host-microorganism interactions1-4. Restriction of available iron by the host during infection is an important defence strategy, described as nutritional immunity5. However, this poses a conundrum for externally facing, absorptive tissues such as the gut epithelium or the plant root epidermis that generate environments that favour iron bioavailability. For example, plant roots acquire iron mostly from the soil and, when iron deficient, increase iron availability through mechanisms that include rhizosphere acidification and secretion of iron chelators6-9. Yet, the elevated iron bioavailability would also be beneficial for the growth of bacteria that threaten plant health. Here we report that microorganism-associated molecular patterns such as flagellin lead to suppression of root iron acquisition through a localized degradation of the systemic iron-deficiency signalling peptide Iron Man 1 (IMA1) in Arabidopsis thaliana. This response is also elicited when bacteria enter root tissues, but not when they dwell on the outer root surface. IMA1 itself has a role in modulating immunity in root and shoot, affecting the levels of root colonization and the resistance to a bacterial foliar pathogen. Our findings reveal an adaptive molecular mechanism of nutritional immunity that affects iron bioavailability and uptake, as well as immune responses.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Bactérias , Peptídeos e Proteínas de Sinalização Intracelular , Ferro , Moléculas com Motivos Associados a Patógenos , Raízes de Plantas , Arabidopsis/imunologia , Arabidopsis/metabolismo , Arabidopsis/microbiologia , Proteínas de Arabidopsis/metabolismo , Bactérias/imunologia , Bactérias/metabolismo , Flagelina/imunologia , Regulação da Expressão Gênica de Plantas , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Ferro/metabolismo , Imunidade Vegetal , Raízes de Plantas/imunologia , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia , Brotos de Planta/imunologia , Brotos de Planta/metabolismo , Brotos de Planta/microbiologia , Rizosfera , Moléculas com Motivos Associados a Patógenos/imunologia , Moléculas com Motivos Associados a Patógenos/metabolismo
12.
Plant J ; 118(3): 839-855, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38271178

RESUMO

Arabidopsis thaliana WRKY proteins are potential targets of pathogen-secreted effectors. RESISTANT TO RALSTONIA SOLANACEARUM 1 (RRS1; AtWRKY52) is a well-studied Arabidopsis nucleotide-binding and leucine-rich repeat (NLR) immune receptor carrying a C-terminal WRKY domain that functions as an integrated decoy. RRS1-R recognizes the effectors AvrRps4 from Pseudomonas syringae pv. pisi and PopP2 from Ralstonia pseudosolanacearum by direct interaction through its WRKY domain. AvrRps4 and PopP2 were previously shown to interact with several AtWRKYs. However, how these effectors selectively interact with their virulence targets remains unknown. Here, we show that several members of subgroup IIIb of the AtWRKY family are targeted by AvrRps4 and PopP2. We demonstrate that several AtWRKYs induce cell death when transiently expressed in Nicotiana benthamiana, indicating the activation of immune responses. AtWRKY54 was the only cell death-inducing AtWRKY that interacted with both AvrRps4 and PopP2. We found that AvrRps4 and PopP2 specifically suppress AtWRKY54-induced cell death. We also demonstrate that the amino acid residues required for the avirulence function of AvrRps4 and PopP2 are critical for suppressing AtWRKY54-induced cell death. AtWRKY54 residues predicted to form a binding interface with AvrRps4 were predominantly located in the DNA binding domain and necessary for inducing cell death. Notably, one AtWRKY54 residue, E164, contributes to affinity with AvrRps4 and is exclusively present among subgroup IIIb AtWRKYs, yet is located outside of the DNA-binding domain. Surprisingly, AtWRKY54 mutated at E164 evaded AvrRps4-mediated cell death suppression. Taking our observations together, we propose that AvrRp4 and PopP2 specifically target AtWRKY54 to suppress plant immune responses.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Proteínas de Bactérias , Nicotiana , Doenças das Plantas , Imunidade Vegetal , Pseudomonas syringae , Arabidopsis/imunologia , Arabidopsis/genética , Arabidopsis/microbiologia , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Morte Celular , Nicotiana/genética , Nicotiana/microbiologia , Nicotiana/imunologia , Nicotiana/metabolismo , Doenças das Plantas/microbiologia , Doenças das Plantas/imunologia , Doenças das Plantas/genética , Imunidade Vegetal/genética , Pseudomonas syringae/patogenicidade , Ralstonia/patogenicidade , Ralstonia/genética , Ralstonia solanacearum/patogenicidade , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
13.
Plant Commun ; 5(5): 100824, 2024 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-38268192

RESUMO

Clubroot caused by the protist Plasmodiophora brassicae is a major disease affecting cultivated Brassicaceae. Using a combination of quantitative trait locus (QTL) fine mapping, CRISPR-Cas9 validation, and extensive analyses of DNA sequence and methylation patterns, we revealed that the two adjacent neighboring NLR (nucleotide-binding and leucine-rich repeat) genes AT5G47260 and AT5G47280 cooperate in controlling broad-spectrum quantitative partial resistance to the root pathogen P. brassicae in Arabidopsis and that they are epigenetically regulated. The variation in DNA methylation is not associated with any nucleotide variation or any transposable element presence/absence variants and is stably inherited. Variations in DNA methylation at the Pb-At5.2 QTL are widespread across Arabidopsis accessions and correlate negatively with variations in expression of the two genes. Our study demonstrates that natural, stable, and transgenerationally inherited epigenetic variations can play an important role in shaping resistance to plant pathogens by modulating the expression of immune receptors.


Assuntos
Arabidopsis , Resistência à Doença , Doenças das Plantas , Arabidopsis/genética , Arabidopsis/imunologia , Doenças das Plantas/genética , Doenças das Plantas/imunologia , Doenças das Plantas/parasitologia , Resistência à Doença/genética , Proteínas NLR/genética , Proteínas NLR/metabolismo , Metilação de DNA , Plasmodioforídeos/fisiologia , Locos de Características Quantitativas/genética , Proteínas de Arabidopsis/genética , Epigênese Genética , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Alelos
14.
Viruses ; 15(11)2023 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-38005916

RESUMO

Virus coat protein (CP)-mediated resistance is considered an effective antiviral defense strategy that has been used to develop robust resistance to viral infection. Rice stripe virus (RSV) causes significant losses in rice production in eastern Asia. We previously showed that the overexpression of RSV CP in Arabidopsis plants results in immunity to RSV infection, using the RSV-Arabidopsis pathosystem, and this CP-mediated viral resistance depends on the function of DCLs and is mostly involved in RNA silencing. However, the special role of DCLs in producing t-siRNAs in CP transgenic Arabidopsis plants is not fully understood. In this study, we show that RSV CP transgenic Arabidopsis plants with the dcl2 mutant background exhibited similar virus susceptibility to non-transgenic plants and were accompanied by the absence of transgene-derived small interfering RNAs (t-siRNAs) from the CP region. The dcl2 mutation eliminated the accumulation of CP-derived t-siRNAs, including those generated by other DCL enzymes. In contrast, we also developed RSV CP transgenic Arabidopsis plants with the dcl4 mutant background, and these CP transgenic plants showed immunity to virus infection and accumulated comparable amounts of CP-derived t-siRNAs to CP transgenic Arabidopsis plants with the wild-type background except for a significant increase in the abundance of 22 nt t-siRNA reads. Overall, our data indicate that DCL2 plays an essential, as opposed to redundant, role in CP-derived t-siRNA production and induces virus resistance in RSV CP transgenic Arabidopsis plants.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Tenuivirus , Arabidopsis/genética , Arabidopsis/imunologia , Arabidopsis/virologia , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Plantas Geneticamente Modificadas , Interferência de RNA , RNA de Cadeia Dupla/metabolismo , RNA Interferente Pequeno/genética , Tenuivirus/genética
15.
Nucleic Acids Res ; 51(21): 11876-11892, 2023 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-37823590

RESUMO

In plants, the detection of microbe-associated molecular patterns (MAMPs) induces primary innate immunity by the activation of mitogen-activated protein kinases (MAPKs). We show here that the MAMP-activated MAPK MPK6 not only modulates defense through transcriptional regulation but also via the ribosomal protein translation machinery. To understand the effects of MPK6 on ribosomes and their constituent ribosomal proteins (RPs), polysomes, monosomes and the phosphorylation status of the RPs, MAMP-treated WT and mpk6 mutant plants were analysed. MAMP-activation induced rapid changes in RP composition of monosomes, polysomes and in the 60S ribosomal subunit in an MPK6-specific manner. Phosphoproteome analysis showed that MAMP-activation of MPK6 regulates the phosphorylation status of the P-stalk ribosomal proteins by phosphorylation of RPP0 and the concomitant dephosphorylation of RPP1 and RPP2. These events coincide with a significant decrease in the abundance of ribosome-bound RPP0s, RPP1s and RPP3s in polysomes. The P-stalk is essential in regulating protein translation by recruiting elongation factors. Accordingly, we found that RPP0C mutant plants are compromised in basal resistance to Pseudomonas syringae infection. These data suggest that MAMP-induced defense also involves MPK6-induced regulation of P-stalk proteins, highlighting a new role of ribosomal regulation in plant innate immunity.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Proteínas Ribossômicas , Arabidopsis/imunologia , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Regulação da Expressão Gênica de Plantas , Fosforilação , Proteínas Ribossômicas/genética , Proteínas Ribossômicas/metabolismo , Ribossomos/genética , Ribossomos/metabolismo , Transdução de Sinais
16.
Nature ; 621(7978): 423-430, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37674078

RESUMO

Translational reprogramming allows organisms to adapt to changing conditions. Upstream start codons (uAUGs), which are prevalently present in mRNAs, have crucial roles in regulating translation by providing alternative translation start sites1-4. However, what determines this selective initiation of translation between conditions remains unclear. Here, by integrating transcriptome-wide translational and structural analyses during pattern-triggered immunity in Arabidopsis, we found that transcripts with immune-induced translation are enriched with upstream open reading frames (uORFs). Without infection, these uORFs are selectively translated owing to hairpins immediately downstream of uAUGs, presumably by slowing and engaging the scanning preinitiation complex. Modelling using deep learning provides unbiased support for these recognizable double-stranded RNA structures downstream of uAUGs (which we term uAUG-ds) being responsible for the selective translation of uAUGs, and allows the prediction and rational design of translating uAUG-ds. We found that uAUG-ds-mediated regulation can be generalized to human cells. Moreover, uAUG-ds-mediated start-codon selection is dynamically regulated. After immune challenge in plants, induced RNA helicases that are homologous to Ded1p in yeast and DDX3X in humans resolve these structures, allowing ribosomes to bypass uAUGs to translate downstream defence proteins. This study shows that mRNA structures dynamically regulate start-codon selection. The prevalence of this RNA structural feature and the conservation of RNA helicases across kingdoms suggest that mRNA structural remodelling is a general feature of translational reprogramming.


Assuntos
Códon de Iniciação , Conformação de Ácido Nucleico , RNA de Cadeia Dupla , RNA Mensageiro , Humanos , Arabidopsis/genética , Arabidopsis/imunologia , Códon de Iniciação/genética , Reconhecimento da Imunidade Inata , Fases de Leitura Aberta/genética , Biossíntese de Proteínas/genética , Biossíntese de Proteínas/imunologia , Ribossomos/metabolismo , RNA de Cadeia Dupla/química , RNA de Cadeia Dupla/genética , RNA de Cadeia Dupla/metabolismo , RNA Mensageiro/genética , Transcriptoma , RNA Helicases DEAD-box/química , RNA Helicases DEAD-box/genética , RNA Helicases DEAD-box/metabolismo , Aprendizado Profundo
17.
Mol Plant ; 16(5): 865-881, 2023 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-37002606

RESUMO

Most organisms adjust their development according to the environmental conditions. For the majority, this implies the sensing of alterations to cell walls caused by different cues. Despite the relevance of this process, few molecular players involved in cell wall sensing are known and characterized. Here, we show that the wall-associated kinase-like protein RESISTANCE TO FUSARIUM OXYSPORUM 1 (RFO1) is required for plant growth and early defense against Fusarium oxysporum and functions by sensing changes in the pectin methylation levels in the cell wall. The RFO1 dwell time at the plasma membrane is affected by the pectin methylation status at the cell wall, regulating MITOGEN-ACTIVATED PROTEIN KINASE and gene expression. We show that the extracellular domain of RFO1 binds de-methylated pectin in vitro, whose distribution in the cell wall is altered during F. oxysporum infection. Further analyses also indicate that RFO1 is required for the BR-dependent plant growth alteration in response to inhibition of pectin de-methyl-esterase activity at the cell wall. Collectively, our work demonstrates that RFO1 is a sensor of the pectin methylation status that plays a unique dual role in plant growth and defense against vascular pathogens.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Fusarium , Pectinas , Imunidade Vegetal , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/imunologia , Arabidopsis/microbiologia , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Parede Celular/metabolismo , Regulação da Expressão Gênica de Plantas , Metilação , Pectinas/metabolismo , Proteínas Quinases/metabolismo , Fusarium/imunologia
18.
J Integr Plant Biol ; 65(7): 1613-1619, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36856338

RESUMO

Plant cells possess a two-layered immune system consisting of pattern-triggered immunity (PTI) and effector-triggered immunity (ETI), mediated by cell surface pattern-recognition receptors and intracellular nucleotide-binding leucine-rich repeat receptors (NLRs), respectively. The CONSTITUTIVE EXPRESSION OF PR GENES 5 (CPR5) nuclear pore complex protein negatively regulates ETI, including ETI-associated hypersensitive response. Here, we show that CPR5 is essential for the activation of various PTI responses in Arabidopsis, such as resistance to the non-adapted bacterium Pseudomonas syringae pv. tomato DC3000 hrcC- . In a forward-genetic screen for suppressors of cpr5, we identified the mediator protein MED4. Mutation of MED4 in cpr5 greatly restored the defective PTI of cpr5. Our findings reveal that CPR5 plays opposite roles in regulating PTI and ETI, and genetically regulates PTI via MED4.


Assuntos
Proteínas de Arabidopsis , Proteínas de Membrana , Imunidade Vegetal , Arabidopsis/imunologia , Proteínas de Arabidopsis/imunologia , Proteínas de Membrana/imunologia , Pseudomonas syringae/patogenicidade , Doenças das Plantas/imunologia , Doenças das Plantas/microbiologia , Receptores de Reconhecimento de Padrão/imunologia , Proteínas NLR/imunologia
19.
Nucleic Acids Res ; 51(9): 4252-4265, 2023 05 22.
Artigo em Inglês | MEDLINE | ID: mdl-36840717

RESUMO

Linker H1 histones play an important role in animal and human pathogenesis, but their function in plant immunity is poorly understood. Here, we analyzed mutants of the three canonical variants of Arabidopsis H1 histones, namely H1.1, H1.2 and H1.3. We observed that double h1.1h1.2 and triple h1.1h1.2h1.3 (3h1) mutants were resistant to Pseudomonas syringae and Botrytis cinerea infections. Transcriptome analysis of 3h1 mutant plants showed H1s play a key role in regulating the expression of early and late defense genes upon pathogen challenge. Moreover, 3h1 mutant plants showed enhanced production of reactive oxygen species and activation of mitogen activated protein kinases upon pathogen-associated molecular pattern (PAMP) treatment. However, 3h1 mutant plants were insensitive to priming with flg22, a well-known bacterial PAMP which induces enhanced resistance in WT plants. The defective defense response in 3h1 upon priming was correlated with altered DNA methylation and reduced global H3K56ac levels. Our data place H1 as a molecular gatekeeper in governing dynamic changes in the chromatin landscape of defense genes during plant pathogen interaction.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Histonas , Interações Hospedeiro-Patógeno , Doenças das Plantas , Imunidade Vegetal , Arabidopsis/genética , Arabidopsis/imunologia , Arabidopsis/metabolismo , Arabidopsis/microbiologia , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Bactérias/imunologia , Cromatina/química , Cromatina/genética , Cromatina/metabolismo , Metilação de DNA , Regulação da Expressão Gênica de Plantas , Histonas/genética , Histonas/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Mutação , Moléculas com Motivos Associados a Patógenos/imunologia , Moléculas com Motivos Associados a Patógenos/metabolismo , Doenças das Plantas/imunologia , Doenças das Plantas/microbiologia , Imunidade Vegetal/genética , Imunidade Vegetal/imunologia , Pseudomonas syringae/imunologia , Pseudomonas syringae/metabolismo , Espécies Reativas de Oxigênio/metabolismo
20.
J Integr Plant Biol ; 65(5): 1312-1327, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36633200

RESUMO

Plant cells recognize microbial patterns with the plasma-membrane-localized pattern-recognition receptors consisting mainly of receptor kinases (RKs) and receptor-like proteins (RLPs). RKs, such as bacterial flagellin receptor FLS2, and their downstream signaling components have been studied extensively. However, newly discovered regulatory components of RLP-mediated immune signaling, such as the nlp20 receptor RLP23, await identification. Unlike RKs, RLPs lack a cytoplasmic kinase domain, instead recruiting the receptor-like kinases (RLKs) BAK1 and SOBIR1. SOBIR1 specifically works as an adapter for RLP-mediated immunity. To identify new regulators of RLP-mediated signaling, we looked for SOBIR1-binding proteins (SBPs) in Arabidopsis thaliana using protein immunoprecipitation and mass spectrometry, identifying two G-type lectin RLKs, SBP1 and SBP2, that physically interacted with SOBIR1. SBP1 and SBP2 showed high sequence similarity, were tandemly repeated on chromosome 4, and also interacted with both RLP23 and BAK1. sbp1 sbp2 double mutants obtained via CRISPR-Cas9 gene editing showed severely impaired nlp20-induced reactive oxygen species burst, mitogen-activated protein kinase (MAPK) activation, and defense gene expression, but normal flg22-induced immune responses. We showed that SBP1 regulated nlp20-induced immunity in a kinase activity-independent manner. Furthermore, the nlp20-induced the RLP23-BAK1 interaction, although not the flg22-induced FLS2-BAK1 interaction, was significantly reduced in sbp1 sbp2. This study identified SBPs as new regulatory components in RLP23 receptor complex that may specifically modulate RLP23-mediated immunity by positively regulating the interaction between the RLP23 receptor and the BAK1 co-receptor.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Imunidade Vegetal , Arabidopsis/genética , Arabidopsis/imunologia , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/imunologia , Proteínas de Arabidopsis/metabolismo , Proteínas Quinases Dependentes de GMP Cíclico/metabolismo , Imunidade/genética , Imunidade/imunologia , Lectinas/genética , Lectinas/imunologia , Lectinas/metabolismo , Imunidade Vegetal/genética , Imunidade Vegetal/imunologia , Proteínas Quinases/genética , Proteínas Quinases/metabolismo , Receptores de Superfície Celular/metabolismo , Receptores Mitogênicos/metabolismo
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