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1.
Int J Mol Sci ; 22(19)2021 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-34639149

RESUMO

Fungal enzymes degrading the plant cell wall, such as xylanases, can activate plant immune responses. The Fusarium graminearum FGSG_03624 xylanase, previously shown to elicit necrosis and hydrogen peroxide accumulation in wheat, was investigated for its ability to induce disease resistance. To this aim, we transiently and constitutively expressed an enzymatically inactive form of FGSG_03624 in tobacco and Arabidopsis, respectively. The plants were challenged with Pseudomonas syringae pv. tabaci or pv. maculicola and Botrytis cinerea. Symptom reduction by the bacterium was evident, while no reduction was observed after B. cinerea inoculation. Compared to the control, the presence of the xylanase gene in transgenic Arabidopsis plants did not alter the basal expression of a set of defense-related genes, and, after the P. syringae inoculation, a prolonged PR1 expression was detected. F. graminearum inoculation experiments of durum wheat spikes exogenously treated with the FGSG_03624 xylanase highlighted a reduction of symptoms in the early phases of infection and a lower fungal biomass accumulation than in the control. Besides, callose deposition was detected in infected spikes previously treated with the xylanase and not in infected control plants. In conclusion, our results highlight the ability of FGSG_03624 to enhance plant immunity, thus decreasing disease severity.


Assuntos
Arabidopsis/imunologia , Botrytis/patogenicidade , Resistência à Doença/imunologia , Endo-1,4-beta-Xilanases/metabolismo , Fusarium/enzimologia , Imunidade Vegetal , Pseudomonas syringae/patogenicidade , Tabaco/imunologia , Arabidopsis/metabolismo , Arabidopsis/microbiologia , Doenças das Plantas/imunologia , Doenças das Plantas/microbiologia , Tabaco/metabolismo , Tabaco/microbiologia
2.
Plant Sci ; 312: 111017, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34620426

RESUMO

As a critical second messenger in plants, Ca2+ is involved in numerous biological processes including biotic and abiotic stress responses. The CBL-interacting protein kinases, known as CIPKs, are essential components in Ca2+-mediated signal transduction pathways. Here, we found that CIPK14 plays a role in the process of regulating immune response in Arabidopsis. The CIPK14 loss-of-function mutants exhibited enhanced resistance to the P. syringae, whereas CIPK14 overexpression plants were more susceptible to bacterial pathogen. Enhanced resistance in cipk14 mutants were accompanied by increased accumulation of SA and elevated expression of defense marker genes (PR1, EDS1, EDS5, ICS1). Overexpression of CIPK14 suppressed Pst DC3000, Pst DC3000 hrcC and flg22 induced generation of ROS and callose deposition. As compared with wild type plants, the expression levels of MPK3/6-dependent PTI marker genes (FRK1, CYP81F2, WAK2, FOX) were up-regulated in cipk14 mutants but down-regulated in CIPK14 overexpression plants after flg22 and elf18 treatment. Additionally, both loss-of-function and gain-of-function of CIPK14 significantly altered the phosphorylation status of MPK3/6 under flg22 treatment, suggesting that CIPK14 is a general modulator of plant immunity at both transcriptional and post-transcriptional level. Taken together, our results uncover that CIPK14 acts as a negative regulator in plant immune response.


Assuntos
Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Resistência à Doença/genética , Resistência à Doença/imunologia , Imunidade Vegetal/genética , Imunidade Vegetal/imunologia , Arabidopsis/metabolismo , Arabidopsis/microbiologia , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Interações Hospedeiro-Patógeno/genética , Interações Hospedeiro-Patógeno/fisiologia , Imunidade/genética , Doenças das Plantas/microbiologia , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Pseudomonas syringae/fisiologia
3.
Plant Sci ; 312: 111036, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34620440

RESUMO

Like in mammals, the plant immune system has evolved to perceive damage. Damaged-associated molecular patterns (DAMPs) are endogenous signals generated in wounded or infected tissue after pathogen or insect attack. Although extracellular DNA (eDNA) is a DAMP signal that induces immune responses, plant responses after eDNA perception remain largely unknown. Here, we report that signaling defenses but not direct defense responses are induced after eDNA applications enhancing broad-range plant protection. A screening of defense signaling and hormone biosynthesis marker genes revealed that OXI1, CML37 and MPK3 are relevant eDNA-Induced Resistance markers (eDNA-IR). Additionally, we observed that eDNA from several Arabidopsis ecotypes and other phylogenetically distant plants such as citrus, bean and, more surprisingly, a monocotyledonous plant such as maize upregulates eDNA-IR marker genes. Using 3,3'-Diaminobenzidine (DAB) and aniline blue staining methods, we observed that H2O2 but not callose was strongly accumulated following self-eDNA treatments. Finally, eDNA resulted in effective induced resistance in Arabidopsis against the pathogens Hyaloperonospora arabidopsidis, Pseudomonas syringae, and Botrytis cinerea and against aphid infestation, reducing the number of nymphs and moving forms. Hence, the unspecificity of DNA origin and the wide range of insects to which eDNA can protect opens many questions about the mechanisms behind eDNA-IR.


Assuntos
Arabidopsis/genética , DNA/farmacologia , Resistência à Doença/genética , Resistência à Doença/imunologia , Imunidade Vegetal/genética , Transdução de Sinais/genética , Zea mays/genética , Arabidopsis/imunologia , Arabidopsis/microbiologia , Brassica/genética , Brassica/imunologia , Brassica/microbiologia , Citrus/genética , Citrus/imunologia , Citrus/microbiologia , Produtos Agrícolas/genética , Produtos Agrícolas/imunologia , Produtos Agrícolas/microbiologia , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Variação Genética , Genótipo , Phaseolus/genética , Phaseolus/imunologia , Phaseolus/microbiologia , Doenças das Plantas/genética , Doenças das Plantas/imunologia , Doenças das Plantas/microbiologia , Solanum/genética , Solanum/imunologia , Solanum/microbiologia , Spinacia oleracea/genética , Spinacia oleracea/imunologia , Spinacia oleracea/microbiologia , Zea mays/imunologia , Zea mays/microbiologia
4.
Int J Mol Sci ; 22(19)2021 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-34638807

RESUMO

Calcium signals are crucial for the activation and coordination of signaling cascades leading to the establishment of plant defense mechanisms. Here, we studied the contribution of CML8, an Arabidopsis calmodulin-like protein in response to Ralstonia solanacearum and to pathogens with different lifestyles, such as Xanthomonas campestris pv. campestris and Phytophtora capsici. We used pathogenic infection assays, gene expression, RNA-seq approaches, and comparative analysis of public data on CML8 knockdown and overexpressing Arabidopsis lines to demonstrate that CML8 contributes to defense mechanisms against pathogenic bacteria and oomycetes. CML8 gene expression is finely regulated at the root level and manipulated during infection with Ralstonia, and CML8 overexpression confers better plant tolerance. To understand the processes controlled by CML8, genes differentially expressed at the root level in the first hours of infection have been identified. Overexpression of CML8 also confers better tolerance against Xanthomonas and Phytophtora, and most of the genes differentially expressed in response to Ralstonia are differentially expressed in these different pathosystems. Collectively, CML8 acts as a positive regulator against Ralstonia solanaceraum and against other vascular or root pathogens, suggesting that CML8 is a multifunctional protein that regulates common downstream processes involved in the defense response of plants to several pathogens.


Assuntos
Arabidopsis/metabolismo , Cálcio/metabolismo , Resistência à Doença , Doenças das Plantas , Transdução de Sinais , Arabidopsis/imunologia , Arabidopsis/microbiologia , Arabidopsis/fisiologia , Regulação da Expressão Gênica de Plantas , Phytophthora , Ralstonia solanacearum , Xanthomonas campestris
5.
Nat Commun ; 12(1): 5969, 2021 10 13.
Artigo em Inglês | MEDLINE | ID: mdl-34645811

RESUMO

The Yersinia outer protein J (YopJ) family effectors are widely deployed through the type III secretion system by both plant and animal pathogens. As non-canonical acetyltransferases, the enzymatic activities of YopJ family effectors are allosterically activated by the eukaryote-specific ligand inositol hexaphosphate (InsP6). However, the underpinning molecular mechanism remains undefined. Here we present the crystal structure of apo-PopP2, a YopJ family member secreted by the plant pathogen Ralstonia solanacearum. Structural comparison of apo-PopP2 with the InsP6-bound PopP2 reveals a substantial conformational readjustment centered in the substrate-binding site. Combining biochemical and computational analyses, we further identify a mechanism by which the association of InsP6 with PopP2 induces an α-helix-to-ß-strand transition in the catalytic core, resulting in stabilization of the substrate recognition helix in the target protein binding site. Together, our study uncovers the molecular basis governing InsP6-mediated allosteric regulation of YopJ family acetyltransferases and further expands the paradigm of fold-switching proteins.


Assuntos
Acetiltransferases/química , Apoproteínas/química , Arabidopsis/microbiologia , Proteínas de Bactérias/química , Ácido Fítico/química , Ralstonia solanacearum/química , Acetiltransferases/genética , Acetiltransferases/metabolismo , Regulação Alostérica , Apoproteínas/genética , Apoproteínas/metabolismo , Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Domínio Catalítico , Clonagem Molecular , Cristalografia por Raios X , Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Vetores Genéticos/química , Vetores Genéticos/metabolismo , Modelos Moleculares , Ácido Fítico/metabolismo , Ligação Proteica , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Domínios e Motivos de Interação entre Proteínas , Ralstonia solanacearum/enzimologia , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Especificidade por Substrato , Tabaco/microbiologia
6.
Nat Commun ; 12(1): 5494, 2021 09 17.
Artigo em Inglês | MEDLINE | ID: mdl-34535661

RESUMO

Sessile plants encode a large number of small peptides and cell surface-resident receptor kinases, most of which have unknown functions. Here, we report that the Arabidopsis receptor kinase MALE DISCOVERER 1-INTERACTING RECEPTOR-LIKE KINASE 2 (MIK2) recognizes the conserved signature motif of SERINE-RICH ENDOGENOUS PEPTIDEs (SCOOPs) from Brassicaceae plants as well as proteins present in fungal Fusarium spp. and bacterial Comamonadaceae, and elicits various immune responses. SCOOP signature peptides trigger immune responses and altered root development in a MIK2-dependent manner with a sub-nanomolar sensitivity. SCOOP12 directly binds to the extracellular leucine-rich repeat domain of MIK2 in vivo and in vitro, indicating that MIK2 is the receptor of SCOOP peptides. Perception of SCOOP peptides induces the association of MIK2 and the coreceptors SOMATIC EMBRYOGENESIS RECEPTOR KINASE 3 (SERK3) and SERK4 and relays the signaling through the cytosolic receptor-like kinases BOTRYTIS-INDUCED KINASE 1 (BIK1) and AVRPPHB SUSCEPTIBLE1 (PBS1)-LIKE 1 (PBL1). Our study identifies a plant receptor that bears a dual role in sensing the conserved peptide motif from phytocytokines and microbial proteins via a convergent signaling relay to ensure a robust immune response.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/imunologia , Arabidopsis/microbiologia , Citocinas/metabolismo , Fusarium/fisiologia , Imunidade Vegetal , Proteínas Quinases/metabolismo , Receptores de Superfície Celular/metabolismo , Motivos de Aminoácidos , Sequência de Aminoácidos , Proteínas de Arabidopsis/química , Mutação/genética , Peptídeos/química , Peptídeos/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Domínios Proteicos , Proteínas Quinases/química , Receptores de Superfície Celular/química
7.
Int J Mol Sci ; 22(17)2021 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-34502265

RESUMO

TGA transcription factor is a member of the D subfamily of the basic region-leucine zippers (bZIP) family. It is a type of transcription factor that was first identified in plants and is the main regulator in plant development and physiological processes, including morphogenesis and seed formation in response to abiotic and biotic stress and maintaining plant growth. The present study examined the sequence of the MaTGA8 transcription factor, the sequence of which belonged to subfamily D of the bZIP and had multiple cis-acting elements such as the G-box, TCA-element, TGACG-element, and P-box. Quantitative real time polymerase chain reaction (qRT-PCR) analyses showed that MaTGA8 was significantly down-regulated by the soil-borne fungus Fusarium oxysporum f. sp. cubense race 4 (Foc TR4). Under the induction of salicylic acid (SA), MaTGA8 was down-regulated, while different members of the MaNPR1 family responded significantly differently. Among them, MaNPR11 and MaNPR3 showed an overall upward trend, and the expression level of MaNPR4, MaNPR8, and MaNPR13 was higher than other members. MaTGA8 is a nuclear-localized transcription factor through strong interaction with MaNPR11 or weaker interaction with MaNPR4, and it is implied that the MaPR gene can be activated. In addition, the MaTGA8 transgenic Arabidopsis has obvious disease resistance and higher chlorophyll content than the wild-type Arabidopsis with the infection of Foc TR4. These results indicate that MaTGA8 may enhance the resistance of bananas to Foc TR4 by interacting with MaNPR11 or MaNPR4. This study provides a basis for further research on the application of banana TGA transcription factors in Foc TR4 stress and disease resistance and molecular breeding programs.


Assuntos
Fatores de Transcrição de Zíper de Leucina Básica/genética , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Resistência à Doença/genética , Musa/genética , Musa/microbiologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Arabidopsis/genética , Arabidopsis/microbiologia , Proteínas de Arabidopsis/metabolismo , Fatores de Transcrição de Zíper de Leucina Básica/química , Fusariose/genética , Fusarium/patogenicidade , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Proteínas de Plantas/química , Raízes de Plantas/genética , Raízes de Plantas/microbiologia , Ácido Salicílico/farmacologia , Alinhamento de Sequência , Transdução de Sinais/efeitos dos fármacos
8.
Biomolecules ; 11(8)2021 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-34439811

RESUMO

Verticillium wilt, primarily induced by the soil-borne fungus Verticillium dahliae, is a serious threat to cotton fiber production. There are a large number of really interesting new gene (RING) domain-containing E3 ubiquitin ligases in Arabidopsis, of which three (At2g39720 (AtRHC2A), At3g46620 (AtRDUF1), and At5g59550 (AtRDUF2)) have a domain of unknown function (DUF) 1117 domain in their C-terminal regions. This study aimed to detect and characterize the RDUF members in cotton, to gain an insight into their roles in cotton's adaptation to environmental stressors. In this study, a total of 6, 7, 14, and 14 RDUF (RING-DUF1117) genes were detected in Gossypium arboretum, G. raimondii, G. hirsutum, and G. barbadense, respectively. These RDUF genes were classified into three groups. The genes in each group were highly conserved based on gene structure and domain analysis. Gene duplication analysis revealed that segmental duplication occurred during cotton evolution. Expression analysis revealed that the GhRDUF genes were widely expressed during cotton growth and under abiotic stresses. Many cis-elements related to hormone response and environment stressors were identified in GhRDUF promoters. The predicted target miRNAs and transcription factors implied that GhRDUFs might be regulated by gra-miR482c, as well as by transcription factors, including MYB, C2H2, and Dof. The GhRDUF genes responded to cold, drought, and salt stress and were sensitive to jasmonic acid, salicylic acid, and ethylene signals. Meanwhile, GhRDUF4D expression levels were enhanced after V. dahliae infection. Subsequently, GhRDUF4D was verified by overexpression in Arabidopsis and virus-induced gene silencing treatment in upland cotton. We observed that V. dahliae resistance was significantly enhanced in transgenic Arabidopsis, and weakened in GhRDUF4D silenced plants. This study conducted a comprehensive analysis of the RDUF genes in Gossypium, hereby providing basic information for further functional studies.


Assuntos
Proteínas de Arabidopsis/genética , Resistência à Doença/genética , Gossypium/genética , Doenças das Plantas/genética , Imunidade Vegetal/genética , Ubiquitina-Proteína Ligases/genética , Adaptação Fisiológica/genética , Adaptação Fisiológica/imunologia , Arabidopsis/classificação , Arabidopsis/genética , Arabidopsis/imunologia , Arabidopsis/microbiologia , Proteínas de Arabidopsis/metabolismo , Ascomicetos/crescimento & desenvolvimento , Ascomicetos/patogenicidade , Sequência de Bases , Dedos de Zinco CYS2-HIS2/genética , Dedos de Zinco CYS2-HIS2/imunologia , Sequência Conservada , Regulação da Expressão Gênica de Plantas , Gossypium/classificação , Gossypium/imunologia , Gossypium/microbiologia , Interações Hospedeiro-Patógeno/genética , Interações Hospedeiro-Patógeno/imunologia , MicroRNAs/genética , MicroRNAs/imunologia , Família Multigênica , Filogenia , Doenças das Plantas/imunologia , Doenças das Plantas/microbiologia , Plantas Geneticamente Modificadas , Regiões Promotoras Genéticas , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Estresse Fisiológico , Fatores de Transcrição/genética , Fatores de Transcrição/imunologia , Ubiquitina-Proteína Ligases/metabolismo
9.
Plant Mol Biol ; 107(1-2): 85-100, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34424501

RESUMO

KEY MESSAGE: Phosphoglycerate Dehydrogenase 1 of the phosphorylated pathway of serine biosynthesis, active in heterotrophic plastids, is required for the synthesis of serine to enable plant growth at high rates of indolic glucosinolate biosynthesis. Plants have evolved effective strategies to defend against various types of pathogens. The synthesis of a multitude of specialized metabolites represents one effective approach to keep plant attackers in check. The synthesis of those defense compounds is cost intensive and requires extensive interaction with primary metabolism. However, how primary metabolism is adjusted to fulfill the requirements of specialized metabolism is still not completely resolved. Here, we studied the role of the phosphorylated pathway of serine biosynthesis (PPSB) for the synthesis of glucosinolates, the main class of defensive compounds in the model plant Arabidopsis thaliana. We show that major genes of the PPSB are co-expressed with genes required for the synthesis of tryptophan, the unique precursor for the formation of indolic glucosinolates (IG). Transcriptional and metabolic characterization of loss-of-function and dominant mutants of ALTERED TRYPTOPHAN1-like transcription factors revealed demand driven activation of PPSB genes by major regulators of IG biosynthesis. Trans-activation of PPSB promoters by ATR1/MYB34 transcription factor in cultured root cells confirmed this finding. The content of IGs were significantly reduced in plants compromised in the PPSB and these plants showed higher sensitivity against treatment with 5-methyl-tryptophan, a characteristic behavior of mutants impaired in IG biosynthesis. We further found that serine produced by the PPSB is required to enable plant growth under conditions of high demand for IG. In addition, PPSB-deficient plants lack the growth promoting effect resulting from interaction with the beneficial root-colonizing fungus Colletotrichum tofieldiae.


Assuntos
Arabidopsis/metabolismo , Colletotrichum/fisiologia , Endófitos/fisiologia , Glucosinolatos/biossíntese , Indóis/metabolismo , Desenvolvimento Vegetal , Raízes de Plantas/microbiologia , Serina/biossíntese , Aminoácidos/metabolismo , Arabidopsis/genética , Arabidopsis/microbiologia , Vias Biossintéticas , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Fosforilação , Estresse Fisiológico/genética , Fatores de Transcrição/metabolismo , Triptofano/biossíntese
10.
Int J Mol Sci ; 22(13)2021 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-34202732

RESUMO

The establishment of plant-fungus mutualistic interaction requires bidirectional molecular crosstalk. Therefore, the analysis of the interacting organisms secretomes would help to understand how such relationships are established. Here, a gel-free shotgun proteomics approach was used to identify the secreted proteins of the plant Arabidopsis thaliana and the mutualistic fungus Trichoderma atroviride during their interaction. A total of 126 proteins of Arabidopsis and 1027 of T. atroviride were identified. Among them, 118 and 780 were differentially modulated, respectively. Bioinformatic analysis unveiled that both organisms' secretomes were enriched with enzymes. In T. atroviride, glycosidases, aspartic endopeptidases, and dehydrogenases increased in response to Arabidopsis. Additionally, amidases, protein-serine/threonine kinases, and hydro-lyases showed decreased levels. Furthermore, peroxidases, cysteine endopeptidases, and enzymes related to the catabolism of secondary metabolites increased in the plant secretome. In contrast, pathogenesis-related proteins and protease inhibitors decreased in response to the fungus. Notably, the glutamate:glyoxylate aminotransferase GGAT1 was secreted by Arabidopsis during its interaction with T. atroviride. Our study showed that GGAT1 is partially required for plant growth stimulation and on the induction of the plant systemic resistance by T. atroviride. Additionally, GGAT1 seems to participate in the negative regulation of the plant systemic resistance against B. cinerea through a mechanism involving H2O2 production.


Assuntos
Arabidopsis/metabolismo , Arabidopsis/microbiologia , Botrytis , Resistência à Doença , Interações Hospedeiro-Patógeno , Metabolômica , Doenças das Plantas/microbiologia , Trichoderma , Biologia Computacional/métodos , Ácido Glutâmico/metabolismo , Metabolômica/métodos , Fenótipo , Desenvolvimento Vegetal , Simbiose , Transaminases/genética , Transaminases/metabolismo
11.
Int J Mol Sci ; 22(12)2021 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-34208600

RESUMO

Coumarins belong to a group of secondary metabolites well known for their high biological activities including antibacterial and antifungal properties. Recently, an important role of coumarins in plant resistance to pathogens and their release into the rhizosphere upon pathogen infection was discovered. It is also well documented that coumarins play a crucial role in the Arabidopsis thaliana growth under Fe-limited conditions. However, the mechanisms underlying interplay between plant resistance, accumulation of coumarins and Fe status, remain largely unknown. In this work, we investigated the effect of both mentioned factors on the disease severity using the model system of Arabidopsis/Dickeya spp. molecular interactions. We evaluated the disease symptoms in Arabidopsis plants, wild-type Col-0 and its mutants defective in coumarin accumulation, grown in hydroponic cultures with contrasting Fe regimes and in soil mixes. Under all tested conditions, Arabidopsis plants inoculated with Dickeya solani IFB0099 strain developed more severe disease symptoms compared to lines inoculated with Dickeya dadantii 3937. We also showed that the expression of genes encoding plant stress markers were strongly affected by D. solani IFB0099 infection. Interestingly, the response of plants to D. dadantii 3937 infection was genotype-dependent in Fe-deficient hydroponic solution.


Assuntos
Cumarínicos/metabolismo , Dickeya/fisiologia , Resistência à Doença , Ferro/metabolismo , Doenças das Plantas/microbiologia , Plantas/metabolismo , Plantas/microbiologia , Arabidopsis/metabolismo , Arabidopsis/microbiologia , Suscetibilidade a Doenças , Hidroponia , Folhas de Planta/microbiologia , Estresse Fisiológico
12.
Int J Mol Sci ; 22(12)2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-34204013

RESUMO

Plant immunity is mediated in large part by specific interactions between a host resistance protein and a pathogen effector protein, named effector-triggered immunity (ETI). ETI needs to be tightly controlled both positively and negatively to enable normal plant growth because constitutively activated defense responses are detrimental to the host. In previous work, we reported that mutations in SUPPRESSOR OF rps4-RLD1 (SRFR1), identified in a suppressor screen, reactivated EDS1-dependent ETI to Pseudomonas syringae pv. tomato (Pto) DC3000. Besides, mutations in SRFR1 boosted defense responses to the generalist chewing insect Spodoptera exigua and the sugar beet cyst nematode Heterodera schachtii. Here, we show that mutations in SRFR1 enhance susceptibility to the fungal necrotrophs Fusarium oxysporum f. sp. lycopersici (FOL) and Botrytis cinerea in Arabidopsis. To translate knowledge obtained in AtSRFR1 research to crops, we generated SlSRFR1 alleles in tomato using a CRISPR/Cas9 system. Interestingly, slsrfr1 mutants increased expression of SA-pathway defense genes and enhanced resistance to Pto DC3000. In contrast, slsrfr1 mutants elevated susceptibility to FOL. Together, these data suggest that SRFR1 is functionally conserved in both Arabidopsis and tomato and functions antagonistically as a negative regulator to (hemi-) biotrophic pathogens and a positive regulator to necrotrophic pathogens.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/imunologia , Arabidopsis/microbiologia , Botrytis/fisiologia , Resistência à Doença/imunologia , Fusarium/fisiologia , Imunidade Vegetal , Alelos , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Sequência de Bases , Sistemas CRISPR-Cas/genética , Resistência à Doença/genética , Edição de Genes , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Vetores Genéticos/metabolismo , Lycopersicon esculentum/genética , Mutação/genética , Imunidade Vegetal/genética , Plasmídeos/genética
13.
Int J Mol Sci ; 22(14)2021 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-34299060

RESUMO

Pseudomonas syringae-secreted HopA1 effectors are important determinants in host range expansion and increased pathogenicity. Their recent acquisitions via horizontal gene transfer in several non-pathogenic Pseudomonas strains worldwide have caused alarming increase in their virulence capabilities. In Arabidopsis thaliana, RESISTANCE TO PSEUDOMONAS SYRINGAE 6 (RPS6) gene confers effector-triggered immunity (ETI) against HopA1pss derived from P. syringae pv. syringae strain 61. Surprisingly, a closely related HopA1pst from the tomato pathovar evades immune detection. These responsive differences in planta between the two HopA1s represents a unique system to study pathogen adaptation skills and host-jumps. However, molecular understanding of HopA1's contribution to overall virulence remain undeciphered. Here, we show that immune-suppressive functions of HopA1pst are more potent than HopA1pss. In the resistance-compromised ENHANCED DISEASE SUSCEPTIBILITY 1 (EDS1) null-mutant, transcriptomic changes associated with HopA1pss-elicited ETI are still induced and carry resemblance to PAMP-triggered immunity (PTI) signatures. Enrichment of HopA1pss interactome identifies proteins with regulatory roles in post-transcriptional and translational processes. With our demonstration here that both HopA1 suppress reporter-gene translations in vitro imply that the above effector-associations with plant target carry inhibitory consequences. Overall, with our results here we unravel possible virulence role(s) of HopA1 in suppressing PTI and provide newer insights into its detection in resistant plants.


Assuntos
Arabidopsis/imunologia , Proteínas de Bactérias/metabolismo , Interações Hospedeiro-Patógeno , Degradação do RNAm Mediada por Códon sem Sentido , Doenças das Plantas/imunologia , Imunidade Vegetal , Pseudomonas syringae/fisiologia , Arabidopsis/genética , Arabidopsis/metabolismo , Arabidopsis/microbiologia , Proteínas de Bactérias/genética , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Virulência
14.
Nat Microbiol ; 6(7): 852-864, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34194036

RESUMO

The plant microbiota consists of a multitude of microorganisms that can affect plant health and fitness. However, it is currently unclear how the plant shapes its leaf microbiota and what role the plant immune system plays in this process. Here, we evaluated Arabidopsis thaliana mutants with defects in different parts of the immune system for an altered bacterial community assembly using a gnotobiotic system. While higher-order mutants in receptors that recognize microbial features and in defence hormone signalling showed substantial microbial community alterations, the absence of the plant NADPH oxidase RBOHD caused the most pronounced change in the composition of the leaf microbiota. The rbohD knockout resulted in an enrichment of specific bacteria. Among these, we identified Xanthomonas strains as opportunistic pathogens that colonized wild-type plants asymptomatically but caused disease in rbohD knockout plants. Strain dropout experiments revealed that the lack of RBOHD unlocks the pathogenicity of individual microbiota members driving dysbiosis in rbohD knockout plants. For full protection, healthy plants require both a functional immune system and a microbial community. Our results show that the NADPH oxidase RBOHD is essential for microbiota homeostasis and emphasizes the importance of the plant immune system in controlling the leaf microbiota.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/microbiologia , Homeostase , Microbiota , NADPH Oxidases/metabolismo , Arabidopsis/enzimologia , Arabidopsis/imunologia , Proteínas de Arabidopsis/genética , Bactérias/classificação , Bactérias/crescimento & desenvolvimento , Bactérias/patogenicidade , Fenômenos Fisiológicos Bacterianos , Genótipo , NADPH Oxidases/genética , Fenótipo , Imunidade Vegetal/genética , Folhas de Planta/enzimologia , Folhas de Planta/imunologia , Folhas de Planta/microbiologia
15.
Nat Microbiol ; 6(9): 1150-1162, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34312531

RESUMO

Roots of different plant species are colonized by bacterial communities, that are distinct even when hosts share the same habitat. It remains unclear to what extent the host actively selects these communities and whether commensals are adapted to a specific plant species. To address this question, we assembled a sequence-indexed bacterial culture collection from roots and nodules of Lotus japonicus that contains representatives of most species previously identified using metagenomics. We analysed taxonomically paired synthetic communities from L. japonicus and Arabidopsis thaliana in a multi-species gnotobiotic system and detected signatures of host preference among commensal bacteria in a community context, but not in mono-associations. Sequential inoculation experiments revealed priority effects during root microbiota assembly, where established communities are resilient to invasion by latecomers, and that host preference of commensal bacteria confers a competitive advantage in their cognate host. Our findings show that host preference in commensal bacteria from diverse taxonomic groups is associated with their invasiveness into standing root-associated communities.


Assuntos
Arabidopsis/fisiologia , Bactérias/isolamento & purificação , Lotus/fisiologia , Microbiota , Raízes de Plantas/microbiologia , Simbiose , Arabidopsis/microbiologia , Bactérias/classificação , Bactérias/genética , Fenômenos Fisiológicos Bacterianos , Lotus/microbiologia , Raízes de Plantas/fisiologia , Microbiologia do Solo
16.
Elife ; 102021 07 22.
Artigo em Inglês | MEDLINE | ID: mdl-34292157

RESUMO

The ratio of microbial population size relative to the amount of host tissue, or 'microbial load', is a fundamental metric of colonization and infection, but it cannot be directly deduced from microbial amplicon data such as 16S rRNA gene counts. Because existing methods to determine load, such as serial dilution plating, quantitative PCR, and whole metagenome sequencing add substantial cost and/or experimental burden, they are only rarely paired with amplicon sequencing. We introduce host-associated microbe PCR (hamPCR), a robust strategy to both quantify microbial load and describe interkingdom microbial community composition in a single amplicon library. We demonstrate its accuracy across multiple study systems, including nematodes and major crops, and further present a cost-saving technique to reduce host overrepresentation in the library prior to sequencing. Because hamPCR provides an accessible experimental solution to the well-known limitations and statistical challenges of compositional data, it has far-reaching potential in culture-independent microbiology.


Assuntos
Microbiota/genética , Reação em Cadeia da Polimerase/métodos , Arabidopsis/microbiologia , Bactérias/classificação , Bactérias/genética , Biblioteca Gênica , Interações entre Hospedeiro e Microrganismos/genética , Humanos , Oomicetos , RNA Ribossômico 16S/genética , Zea mays/microbiologia
17.
Int J Mol Sci ; 22(11)2021 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-34073109

RESUMO

Colletotrichum higginsianum is an important hemibiotrophic plant pathogen that causes crucifer anthracnose worldwide. To date, some hexose transporters have been identified in fungi. However, the functions of hexose transporters in virulence are not clear in hemibiotrophic phytopathogens. In this study, we identified and characterized a new hexose transporter gene named ChHxt6 from a T-DNA insertion pathogenicity-deficient mutant G256 in C. higginsianum. Expression profiling analysis revealed that six ChHxt genes, ChHxt1 to ChHxt6, exhibited specific expression patterns in different infection phases of C. higginsianum. The ChHxt1 to ChHxt6 were separately deleted using the principle of homologous recombination. ChHxt1 to ChHxt6 deletion mutants grew normally on PDA plates, but only the virulence of ChHxt4 and ChHxt6 deletion mutants was reduced. ChHxt4 was required for fungal infection in both biotrophic and necrotrophic stages, while ChHxt6 was important for formation of necrotrophic hyphae during infection. In addition, ChHxts were functional in uptake of different hexoses, but only ChHxt6-expressing cells could grow on all five hexoses, indicating that the ChHxt6 was a central hexose transporter and crucial for hexose uptake. Site-directed mutation of T169S and P221L positions revealed that these two positions were necessary for hexose transport, whereas only the mutation Thr169 caused reduced virulence and defect in formation of necrotrophic hyphae. Taken together, ChHxt6 might regulate fungal virulence by modulating the utilization of hexose.


Assuntos
Proteínas Fúngicas/fisiologia , Proteínas de Transporte de Monossacarídeos/metabolismo , Doenças das Plantas/microbiologia , Fatores de Virulência/metabolismo , Arabidopsis/microbiologia , Brassica/microbiologia , Colletotrichum/genética , Colletotrichum/metabolismo , Colletotrichum/patogenicidade , Regulação Fúngica da Expressão Gênica , Genes Fúngicos , Hexoses/metabolismo , Virulência
18.
Nat Commun ; 12(1): 3829, 2021 06 22.
Artigo em Inglês | MEDLINE | ID: mdl-34158504

RESUMO

While beneficial plant-microbe interactions are common in nature, direct evidence for the evolution of bacterial mutualism is scarce. Here we use experimental evolution to causally show that initially plant-antagonistic Pseudomonas protegens bacteria evolve into mutualists in the rhizosphere of Arabidopsis thaliana within six plant growth cycles (6 months). This evolutionary transition is accompanied with increased mutualist fitness via two mechanisms: (i) improved competitiveness for root exudates and (ii) enhanced tolerance to the plant-secreted antimicrobial scopoletin whose production is regulated by transcription factor MYB72. Crucially, these mutualistic adaptations are coupled with reduced phytotoxicity, enhanced transcription of MYB72 in roots, and a positive effect on plant growth. Genetically, mutualism is associated with diverse mutations in the GacS/GacA two-component regulator system, which confers high fitness benefits only in the presence of plants. Together, our results show that rhizosphere bacteria can rapidly evolve along the parasitism-mutualism continuum at an agriculturally relevant evolutionary timescale.


Assuntos
Arabidopsis/genética , Raízes de Plantas/genética , Pseudomonas/genética , Rizosfera , Simbiose/genética , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/microbiologia , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Evolução Molecular , Regulação da Expressão Gênica de Plantas , Aptidão Genética , Interações Hospedeiro-Patógeno/genética , Mutação , Fenótipo , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , Pseudomonas/fisiologia , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
19.
Nat Commun ; 12(1): 3335, 2021 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-34099661

RESUMO

Plants utilise intracellular nucleotide-binding, leucine-rich repeat (NLR) immune receptors to detect pathogen effectors and activate local and systemic defence. NRG1 and ADR1 "helper" NLRs (RNLs) cooperate with enhanced disease susceptibility 1 (EDS1), senescence-associated gene 101 (SAG101) and phytoalexin-deficient 4 (PAD4) lipase-like proteins to mediate signalling from TIR domain NLR receptors (TNLs). The mechanism of RNL/EDS1 family protein cooperation is not understood. Here, we present genetic and molecular evidence for exclusive EDS1/SAG101/NRG1 and EDS1/PAD4/ADR1 co-functions in TNL immunity. Using immunoprecipitation and mass spectrometry, we show effector recognition-dependent interaction of NRG1 with EDS1 and SAG101, but not PAD4. An EDS1-SAG101 complex interacts with NRG1, and EDS1-PAD4 with ADR1, in an immune-activated state. NRG1 requires an intact nucleotide-binding P-loop motif, and EDS1 a functional EP domain and its partner SAG101, for induced association and immunity. Thus, two distinct modules (NRG1/EDS1/SAG101 and ADR1/EDS1/PAD4) mediate TNL receptor defence signalling.


Assuntos
Proteínas de Arabidopsis/metabolismo , Hidrolases de Éster Carboxílico/metabolismo , Proteínas de Ligação a DNA/metabolismo , Neuregulina-1/metabolismo , Imunidade Vegetal/fisiologia , Receptores Imunológicos/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Arabidopsis/microbiologia , Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/genética , Hidrolases de Éster Carboxílico/química , Hidrolases de Éster Carboxílico/genética , Morte Celular , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/genética , Imunidade Inata , Neuregulina-1/química , Neuregulina-1/genética , Doenças das Plantas/imunologia , Doenças das Plantas/microbiologia , Imunidade Vegetal/genética , Plantas Geneticamente Modificadas , Domínios Proteicos , Pseudomonas syringae , Receptores Imunológicos/química , Receptores Imunológicos/genética , Transdução de Sinais , Tabaco/genética , Tabaco/metabolismo
20.
Int J Mol Sci ; 22(9)2021 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-34066536

RESUMO

Plant food production is severely affected by fungi; to cope with this problem, farmers use synthetic fungicides. However, the need to reduce fungicide application has led to a search for alternatives, such as biostimulants. Rare-earth elements (REEs) are widely used as biostimulants, but their mode of action and their potential as an alternative to synthetic fungicides have not been fully studied. Here, the biostimulant effect of gadolinium (Gd) is explored using the plant-pathosystem Arabidopsis thaliana-Botrytis cinerea. We determine that Gd induces local, systemic, and long-lasting plant defense responses to B. cinerea, without affecting fungal development. The physiological changes induced by Gd have been related to its structural resemblance to calcium. However, our results show that the calcium-induced defense response is not sufficient to protect plants against B. cinerea, compared to Gd. Furthermore, a genome-wide transcriptomic analysis shows that Gd induces plant defenses and modifies early and late defense responses. However, the resistance to B. cinerea is dependent on JA/ET-induced responses. These data support the conclusion that Gd can be used as a biocontrol agent for B. cinerea. These results are a valuable tool to uncover the molecular mechanisms induced by REEs.


Assuntos
Arabidopsis/imunologia , Arabidopsis/microbiologia , Botrytis/fisiologia , Ciclopentanos/metabolismo , Etilenos/metabolismo , Gadolínio/farmacologia , Oxilipinas/metabolismo , Substâncias Protetoras/farmacologia , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Botrytis/efeitos dos fármacos , Botrytis/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Doenças das Plantas/imunologia , Doenças das Plantas/microbiologia , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/crescimento & desenvolvimento , Espécies Reativas de Oxigênio/metabolismo , Ácido Salicílico/metabolismo , Estresse Fisiológico/efeitos dos fármacos , Ativação Transcricional/efeitos dos fármacos , Ativação Transcricional/genética
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