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1.
Int J Mol Sci ; 25(5)2024 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-38473940

RESUMO

Phytopathogenic fungi normally secrete large amounts of CWDEs to enhance infection of plants. In this study, we identified and characterized a secreted glycosyl hydrolase 5 family member in Sclerotinia sclerotiorum (SsGH5, Sclerotinia sclerotiorum Glycosyl Hydrolase 5). SsGH5 was significantly upregulated during the early stages of infection. Knocking out SsGH5 did not affect the growth and acid production of S. sclerotiorum but resulted in decreased glucan utilization and significantly reduced virulence. In addition, Arabidopsis thaliana expressing SsGH5 became more susceptible to necrotrophic pathogens and basal immune responses were inhibited in these plants. Remarkably, the lost virulence of the ΔSsGH5 mutants was restored after inoculating onto SsGH5 transgenic Arabidopsis. In summary, these results highlight that S. sclerotiorum suppresses the immune responses of Arabidopsis through secreting SsGH5, and thus exerts full virulence for successful infection.


Assuntos
Arabidopsis , Ascomicetos , Arabidopsis/metabolismo , Hidrolases/metabolismo , Virulência , Imunidade Vegetal/fisiologia , Plantas , Doenças das Plantas/microbiologia
2.
Adv Virus Res ; 118: 77-212, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38461031

RESUMO

Resistance to infection by plant viruses involves proteins encoded by plant resistance (R) genes, viz., nucleotide-binding leucine-rich repeats (NLRs), immune receptors. These sensor NLRs are activated either directly or indirectly by viral protein effectors, in effector-triggered immunity, leading to induction of defense signaling pathways, resulting in the synthesis of numerous downstream plant effector molecules that inhibit different stages of the infection cycle, as well as the induction of cell death responses mediated by helper NLRs. Early events in this process involve recognition of the activation of the R gene response by various chaperones and the transport of these complexes to the sites of subsequent events. These events include activation of several kinase cascade pathways, and the syntheses of two master transcriptional regulators, EDS1 and NPR1, as well as the phytohormones salicylic acid, jasmonic acid, and ethylene. The phytohormones, which transit from a primed, resting states to active states, regulate the remainder of the defense signaling pathways, both directly and by crosstalk with each other. This regulation results in the turnover of various suppressors of downstream events and the synthesis of various transcription factors that cooperate and/or compete to induce or suppress transcription of either other regulatory proteins, or plant effector molecules. This network of interactions results in the production of defense effectors acting alone or together with cell death in the infected region, with or without the further activation of non-specific, long-distance resistance. Here, we review the current state of knowledge regarding these processes and the components of the local responses, their interactions, regulation, and crosstalk.


Assuntos
Reguladores de Crescimento de Plantas , Imunidade Vegetal , Imunidade Vegetal/genética , Reguladores de Crescimento de Plantas/metabolismo , Plantas , Transdução de Sinais , Doenças das Plantas/genética
3.
Sci Adv ; 10(11): eadk3126, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38489361

RESUMO

Perception of pathogen/microbial-associated molecular patterns (P/MAMPs) by plant cell surface receptors leads to a sustained burst of reactive oxygen species (ROS), a key feature of P/MAMP-triggered immunity (PTI). Here we report that P/MAMP recognition leads to a rapid nitrosative burst, initiating the accumulation of nitric oxide (NO), subsequently leading to S-nitrosylation of the receptor-like cytoplasmic kinase (RLCK), botrytis-induced kinase 1 (BIK1), at Cys80. This redox-based, posttranslational modification, promotes the phosphorylation of BIK1, subsequently resulting in BIK1 activation and stabilization. Further, BIK1 S-nitrosylation increases its physical interaction with RBOHD, the source of the apoplastic oxidative burst, promoting ROS formation. Our data identify mechanistic links between rapid NO accumulation and the expression of PTI, providing insights into plant immunity.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Imunidade Vegetal
4.
Microb Pathog ; 189: 106599, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38428471

RESUMO

We have functionally evaluated a transcription factor CaMYB59 for its role in pepper immune responses to Ralstonia solanacearum attack and high temperature-high humidity (HTHH). Exposure to R. solanacearum inoculation (RSI) and HTHH resulted in up-regulation of this nucleus-localized TF. Function of this TF was confirmed by performing loss of function assay of CaMYB59 by VIGS (virus-induced gene silencing). Plants with silenced CaMYB59 displayed not only compromised pepper immunity against RSI but also impaired tolerance to HTHH along with decreased hypersensitive response (HR). This impairment in defense function was fully linked with low induction of stress-linked genes like CaPO2, CaPR1, CaAcc and thermo-tolerance linked CaHSP24 as well as CaHsfB2a. Conversely, transient overexpression of CaMYB59 enhanced pepper immunity. This reveals that CaMYB59 positively regulated host defense against RSI and HTHH by means of HR like mimic cell death, H2O2 production and up-regulation of defense as well as thermo-tolerance associated genes. These changes in attributes collectively confirm the role of CaMYB59 as a positive regulator of pepper immunity against R. solanacearum. We recommend that such positive regulation of pepper defense is dynamically supported by phyto-hormone signaling and transcriptional web of defense genes. These integrated and interlinked events stabilize plant growth and survival under abiotic and biotic stresses.


Assuntos
Reguladores de Crescimento de Plantas , Ralstonia solanacearum , Humanos , Reguladores de Crescimento de Plantas/genética , Resistência à Doença/genética , Imunidade Vegetal/genética , Ralstonia solanacearum/genética , Peróxido de Hidrogênio/metabolismo , Temperatura , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Doenças das Plantas/genética
5.
Nat Commun ; 15(1): 2559, 2024 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-38519521

RESUMO

Proteins containing a ubiquitin regulatory X (UBX) domain are cofactors of Cell Division Cycle 48 (CDC48) and function in protein quality control. However, whether and how UBX-containing proteins participate in host-microbe interactions remain unclear. Here we show that MoNLE1, an effector from the fungal pathogen Magnaporthe oryzae, is a core virulence factor that suppresses rice immunity by specifically interfering with OsPUX8B.2. The UBX domain of OsPUX8B.2 is required for its binding to OsATG8 and OsCDC48-6 and controls its 26 S proteasome-dependent stability. OsPUX8B.2 and OsCDC48-6 positively regulate plant immunity against blast fungus, while the high-temperature tolerance heat-shock protein OsBHT, a putative cytoplasmic substrate of OsPUX8B.2-OsCDC48-6, negatively regulates defense against blast infection. MoNLE1 promotes the nuclear migration and degradation of OsPUX8B.2 and disturbs its association with OsBHT. Given the high conservation of MoNLE1 among fungal isolates, plants with broad and durable blast resistance might be generated by engineering intracellular proteins resistant to MoNLE1.


Assuntos
Magnaporthe , Oryza , Interações Hospedeiro-Patógeno , Imunidade Vegetal/genética , Transporte Biológico , Plantas Geneticamente Modificadas/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Oryza/metabolismo , Doenças das Plantas/microbiologia , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo
6.
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
7.
Mol Plant Microbe Interact ; 37(2): 73-83, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38416059

RESUMO

Embedded in the plasma membrane of plant cells, receptor kinases (RKs) and receptor proteins (RPs) act as key sentinels, responsible for detecting potential pathogenic invaders. These proteins were originally characterized more than three decades ago as disease resistance (R) proteins, a concept that was formulated based on Harold Flor's gene-for-gene theory. This theory implies genetic interaction between specific plant R proteins and corresponding pathogenic effectors, eliciting effector-triggered immunity (ETI). Over the years, extensive research has unraveled their intricate roles in pathogen sensing and immune response modulation. RKs and RPs recognize molecular patterns from microbes as well as dangers from plant cells in initiating pattern-triggered immunity (PTI) and danger-triggered immunity (DTI), which have intricate connections with ETI. Moreover, these proteins are involved in maintaining immune homeostasis and preventing autoimmunity. This review showcases seminal studies in discovering RKs and RPs as R proteins and discusses the recent advances in understanding their functions in sensing pathogen signals and the plant cell integrity and in preventing autoimmunity, ultimately contributing to a robust and balanced plant defense response. [Formula: see text] The author(s) have dedicated the work to the public domain under the Creative Commons CC0 "No Rights Reserved" license by waiving all of his or her rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law, 2024.


Assuntos
Plantas , Receptores de Reconhecimento de Padrão , Receptores de Reconhecimento de Padrão/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Resistência à Doença , Proteínas de Transporte , Imunidade Vegetal/genética , Doenças das Plantas
8.
BMC Plant Biol ; 24(1): 154, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38424489

RESUMO

BACKGROUND: Soybean is one of the most cultivated crops globally and a staple food for much of the world's population. The annual global crop losses due to infection by Phytophthora sojae is currently estimated at $20B USD, yet we have limited understanding of the role of lipid mediators in the adaptative strategies used by the host plant to limit infection. Since root is the initial site of this infection, we examined the infection process in soybean root infected with Phytophthora sojae using scanning electron microscopy to observe the changes in root morphology and a multi-modal lipidomics approach to investigate how soybean cultivars remodel their lipid mediators to successfully limit infection by Phytophthora sojae. RESULTS: The results reveal the presence of elevated biogenic crystals and more severe damaged cells in the root morphology of the infected susceptible cultivar compared to the infected tolerant cultivars. Furthermore, induced accumulation of stigmasterol was observed in the susceptible cultivar whereas, induced accumulation of phospholipids and glycerolipids occurred in tolerant cultivar. CONCLUSION: The altered lipidome reported in this study suggest diacylglycerol and phosphatidic acid mediated lipid signalling impacting phytosterol anabolism appears to be a strategy used by tolerant soybean cultivars to successfully limit infection and colonization by Phytophthora sojae.


Assuntos
Phytophthora , Phytophthora/fisiologia , Resistência à Doença , Imunidade Vegetal , Fosfolipídeos , Doenças das Plantas
9.
Sci Rep ; 14(1): 3489, 2024 02 12.
Artigo em Inglês | MEDLINE | ID: mdl-38347062

RESUMO

Following localized infection, the entire plant foliage becomes primed for enhanced defense. However, specific genes induced during defense priming (priming-marker genes) and those showing increased expression in defense-primed plants upon rechallenge (priming-readout genes) remain largely unknown. In our Arabidopsis thaliana study, genes AT1G76960 (function unknown), CAX3 (encoding a vacuolar Ca2+/H+ antiporter), and CRK4 (encoding a cysteine-rich receptor-like protein kinase) were strongly expressed during Pseudomonas cannabina pv. alisalensis-induced defense priming, uniquely marking the primed state for enhanced defense. Conversely, PR1 (encoding a pathogenesis-related protein), RLP23 and RLP41 (both encoding receptor-like proteins) were similarly activated in defense-primed plants before and after rechallenge, suggesting they are additional marker genes for defense priming. In contrast, CASPL4D1 (encoding Casparian strip domain-like protein 4D1), FRK1 (encoding flg22-induced receptor-like kinase), and AT3G28510 (encoding a P loop-containing nucleoside triphosphate hydrolases superfamily protein) showed minimal activation in uninfected, defense-primed, or rechallenged plants, but intensified in defense-primed plants after rechallenge. Notably, mutation in only priming-readout gene NHL25 (encoding NDR1/HIN1-like protein 25) impaired both defense priming and systemic acquired resistance, highlighting its previously undiscovered pivotal role in systemic plant immunity.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/fisiologia , Pseudomonas/genética , Pseudomonas/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Imunidade Vegetal/genética , Pseudomonas syringae/metabolismo , Doenças das Plantas/genética , Regulação da Expressão Gênica de Plantas , Receptores de Superfície Celular/metabolismo
11.
Cell Host Microbe ; 32(3): 425-440.e7, 2024 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-38309260

RESUMO

In plant immunity, phosphatidic acid (PA) regulates reactive oxygen species (ROS) by binding to respiratory burst oxidase homolog D (RBOHD), an NADPH oxidase responsible for ROS production. Here, we analyze the influence of PA binding on RBOHD activity and the mechanism of RBOHD-bound PA generation. PA binding enhances RBOHD protein stability by inhibiting vacuolar degradation, thereby increasing chitin-induced ROS production. Mutations in diacylglycerol kinase 5 (DGK5), which phosphorylates diacylglycerol to produce PA, impair chitin-induced PA and ROS production. The DGK5 transcript DGK5ß (but not DGK5α) complements reduced PA and ROS production in dgk5-1 mutants, as well as resistance to Botrytis cinerea. Phosphorylation of S506 residue in the C-terminal calmodulin-binding domain of DGK5ß contributes to the activation of DGK5ß to produce PA. These findings suggest that DGK5ß-derived PA regulates ROS production by inhibiting RBOHD protein degradation, elucidating the role of PA-ROS interplay in immune response regulation.


Assuntos
Proteínas de Arabidopsis , Proteínas de Arabidopsis/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Ácidos Fosfatídicos/metabolismo , NADPH Oxidases/genética , Imunidade Vegetal/genética , Quitina/metabolismo , Regulação da Expressão Gênica de Plantas
12.
New Phytol ; 242(1): 170-191, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38348532

RESUMO

Plants activate immunity upon recognition of pathogen-associated molecular patterns. Although phytopathogens have evolved a set of effector proteins to counteract plant immunity, some effectors are perceived by hosts and induce immune responses. Here, we show that two secreted ribonuclease effectors, SRN1 and SRN2, encoded in a phytopathogenic fungus, Colletotrichum orbiculare, induce cell death in a signal peptide- and catalytic residue-dependent manner, when transiently expressed in Nicotiana benthamiana. The pervasive presence of SRN genes across Colletotrichum species suggested the conserved roles. Using a transient gene expression system in cucumber (Cucumis sativus), an original host of C. orbiculare, we show that SRN1 and SRN2 potentiate host pattern-triggered immunity responses. Consistent with this, C. orbiculare SRN1 and SRN2 deletion mutants exhibited increased virulence on the host. In vitro analysis revealed that SRN1 specifically cleaves single-stranded RNAs at guanosine, leaving a 3'-end phosphate. Importantly, the potentiation of C. sativus responses by SRN1 and SRN2, present in the apoplast, depends on ribonuclease catalytic residues. We propose that the pathogen-derived apoplastic guanosine-specific single-stranded endoribonucleases lead to immunity potentiation in plants.


Assuntos
Cucumis sativus , Ribonucleases , Cucumis sativus/microbiologia , Fungos , Plantas , Imunidade , Doenças das Plantas/microbiologia , Imunidade Vegetal
13.
Gene ; 907: 148260, 2024 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-38342252

RESUMO

Pokkah Boeng disease (PBD), caused by Fusarium sacchari, severely affects sugarcane yield and quality. Necrosis-inducing secreted protein 1 (Nis1) is a fungal secreted effector that induces necrotic lesions in plants. It interacts with host receptor-like kinases and inhibits their kinase activity. FsNis1 contains the Nis1 structure and triggered a pathogen-associated molecular pattern-triggered immune response in Nicotiana benthamiana, as reflected by causing reactive oxygen species production, callose accumulation, and the upregulated expression of defense response genes. Knockout of this gene in F. sacchari revealed a significant reduction in its pathogenicity, whereas the pathogenicity of the complementary mutant recovered to the wild-type levels, making this gene an important virulence factor for F. sacchari. In addition, the signal peptide of FsNis1 was required for the induction of cell death and PTI response in N. benthamiana. Thus, FsNis1 may not only be a key virulence factor for F. sacchari but may also induce defense responses in plants. These findings provide new insights into the function of Nis1 in host-pathogen interactions.


Assuntos
Fusarium , Fusarium/genética , Imunidade Vegetal/genética , Virulência/genética , Fatores de Virulência/genética , Doenças das Plantas/genética , Doenças das Plantas/microbiologia
14.
Science ; 383(6684): 732-739, 2024 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-38359129

RESUMO

Polygalacturonase-inhibiting proteins (PGIPs) interact with pathogen-derived polygalacturonases to inhibit their virulence-associated plant cell wall-degrading activity but stimulate immunity-inducing oligogalacturonide production. Here we show that interaction between Phaseolus vulgaris PGIP2 (PvPGIP2) and Fusarium phyllophilum polygalacturonase (FpPG) enhances substrate binding, resulting in inhibition of the enzyme activity of FpPG. This interaction promotes FpPG-catalyzed production of long-chain immunoactive oligogalacturonides, while diminishing immunosuppressive short oligogalacturonides. PvPGIP2 binding creates a substrate binding site on PvPGIP2-FpPG, forming a new polygalacturonase with boosted substrate binding activity and altered substrate preference. Structure-based engineering converts a putative PGIP that initially lacks FpPG-binding activity into an effective FpPG-interacting protein. These findings unveil a mechanism for plants to transform pathogen virulence activity into a defense trigger and provide proof of principle for engineering PGIPs with broader specificity.


Assuntos
Fusarium , Phaseolus , Imunidade Vegetal , Proteínas de Plantas , Poligalacturonase , Fatores de Virulência , Imunidade Inata , Proteínas de Plantas/metabolismo , Poligalacturonase/metabolismo , Fatores de Virulência/metabolismo , Fusarium/imunologia , Fusarium/patogenicidade , Phaseolus/imunologia , Phaseolus/microbiologia
15.
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
17.
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
18.
Plant Sci ; 342: 112033, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38354753

RESUMO

The receptor-like cytoplasmic kinase BRASSINOSTEROID-SIGNALING KINASE1 (BSK1) interacts with pattern recognition receptor (PRR) FLAGELLIN SENSING2 (FLS2) and positively regulates plant innate immunity in Arabidopsis thaliana. However, the molecular components involved in BSK1-mediated immune signaling remain largely unknown. To further explore the molecular mechanism underlying BSK1-mediated disease resistance, we screened two cysteine proteases, RESPONSE TO DEHYDRATION 19 (RD19) and RD19-LIKE 2 (RDL2), as BSK1-binding partners. Overexpression of RD19, but not RDL2, displayed an autoimmune phenotype, presenting programmed cell death and enhanced resistance to multiple pathogens. Interestingly, RD19-mediated immune activation depends on BSK1, as knockout of BSK1 in RD19-overexpressing plants rescued their autoimmunity and abolished the increased resistance. Furthermore, we found that BSK1 plays a positive role in maintaining RD19 protein abundance in Arabidopsis. Our results provide new insights into BSK1-mediated immune signaling and reveal a potential mechanism by which BSK1 stabilizes RD19 to promote effective immune output.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Cisteína Proteases , Arabidopsis/metabolismo , Resistência à Doença/genética , Brassinosteroides/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Cisteína Proteases/genética , Cisteína Proteases/metabolismo , Desidratação , Imunidade Vegetal/genética
19.
New Phytol ; 242(2): 576-591, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38362937

RESUMO

Leucine-rich repeat receptor-like kinases (LRR-RLKs) comprise the largest class of membrane-localized receptor-like kinases in plants. Leucine-rich repeat receptor-like kinases are key immune sectors contributing to pattern-triggered immunity (PTI), but whether LRR-RLK mediates effector-triggered immunity (ETI) in plants remains unclear. In this study, we evaluated the function of LRR-RLKs in regulating ETI by using a virus-induced gene silencing (VIGS)-based reverse genetic screening assay, and identified a LRR-RLK named ETI-dependent receptor-like kinase 1 (EDK1) required for ETI triggered by the avirulence effector AVRblb2 secreted by Phytophthora infestans and its cognate receptor Rpi-blb2. Silencing or knockout of EDK1 compromised immunity mediated by Rpi-blb2 and the cell death triggered by recognition of AVRblb2. NLR-required for cell death 4 (NRC4), a signaling component acts downstream of Rpi-blb2, was identified that interacts with EDK1 using the LC-MS analysis and the interaction was further evaluated by co-immunoprecipitation. EDK1 promotes protein accumulation of NRC4 in a kinase-dependent manner and positively regulates resistance to P. infestans in Nicotiana benthamiana. Our study revealed that EDK1 positively regulates plant ETI through modulating accumulation of the NLR signaling component NRC4, representing a new regulatory role of the membrane-localized LRR-RLKs in plant immunity.


Assuntos
Reconhecimento da Imunidade Inata , /genética , Leucina , Plantas , Imunidade Vegetal , Morte Celular , Doenças das Plantas/genética
20.
Plant Cell Environ ; 47(3): 871-884, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38164043

RESUMO

Symbiotic nitrogen fixation (SNF) is a crucial process for nitrogen geochemical cycling and plant-microbe interactions. Water-soluble humic acid (WSHM), an active component of soil humus, has been shown to promote SNF in the legume-rhizobial symbiosis, but its molecular mechanism remains largely unknown. To reveal the SNF-promoting mechanism, we conducted transcriptomic analysis on soybean treated with WSHM. Our findings revealed that up- and downregulated differentially expressed genes (DEGs) were mainly involved in plant cell-wall/membrane formation and plant defence/immunity in the early stage, while the late stage was marked by the flavonoid synthesis and ethylene biosynthetic process. Further study on representative DEGs showed that WSHM could inhibit GmBAK1d-mediated immunity and BR signalling, thereby promoting rhizobial colonisation, infection, and nodulation, while not favoring pathogenic bacteria colonisation on the host plant. Additionally, we also found that the ethylene pathway is necessary for promoting the soybean nodulation by WSHM. This study not only provides a significant advance in our understanding of the molecular mechanism of WSHM in promoting SNF, but also provides evidence of the beneficial interactions among the biostimulator, host plant, and soil microbes, which have not been previously reported.


Assuntos
Rhizobium , Nodulação , Substâncias Húmicas , Fixação de Nitrogênio , Etilenos/metabolismo , Imunidade Vegetal , Simbiose , Nódulos Radiculares de Plantas/microbiologia
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