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1.
Nat Commun ; 11(1): 1123, 2020 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-32111840

RESUMO

Stem rust is an important disease of wheat that can be controlled using resistance genes. The gene SuSr-D1 identified in cultivar 'Canthatch' suppresses stem rust resistance. SuSr-D1 mutants are resistant to several races of stem rust that are virulent on wild-type plants. Here we identify SuSr-D1 by sequencing flow-sorted chromosomes, mutagenesis, and map-based cloning. The gene encodes Med15, a subunit of the Mediator Complex, a conserved protein complex in eukaryotes that regulates expression of protein-coding genes. Nonsense mutations in Med15b.D result in expression of stem rust resistance. Time-course RNAseq analysis show a significant reduction or complete loss of differential gene expression at 24 h post inoculation in med15b.D mutants, suggesting that transcriptional reprogramming at this time point is not required for immunity to stem rust. Suppression is a common phenomenon and this study provides novel insight into suppression of rust resistance in wheat.


Assuntos
Resistência à Doença/genética , Complexo Mediador/genética , Doenças das Plantas/genética , Triticum/genética , Basidiomycota/patogenicidade , Mapeamento Cromossômico , Cromossomos de Plantas/genética , Duplicação Gênica , Expressão Gênica , Regulação da Expressão Gênica de Plantas , Genes de Plantas/genética , Mutação , Fenótipo , Doenças das Plantas/imunologia , Doenças das Plantas/microbiologia , Imunidade Vegetal/genética , Poaceae/classificação , Poaceae/genética , Triticum/imunologia , Triticum/microbiologia
2.
Cell Host Microbe ; 27(3): 405-417.e6, 2020 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-32101702

RESUMO

In certain plant hybrids, immunity signaling is initiated when immune components interact in the absence of a pathogen trigger. In Arabidopsis thaliana, such autoimmunity and cell death are linked to variants of the NLR RPP7 and the RPW8 proteins involved in broad-spectrum resistance. We uncover the molecular basis for this autoimmunity and demonstrate that a homolog of RPW8, HR4Fei-0, can trigger the assembly of a higher-order RPP7 complex, with autoimmunity signaling as a consequence. HR4Fei-0-mediated RPP7 oligomerization occurs via the RPP7 C-terminal leucine-rich repeat (LRR) domain and ATP-binding P-loop. RPP7 forms a higher-order complex only in the presence of HR4Fei-0 and not with the standard HR4 variant, which is distinguished from HR4Fei-0 by length variation in C-terminal repeats. Additionally, HR4Fei-0 can independently form self-oligomers, which directly kill cells in an RPP7-independent manner. Our work provides evidence for a plant resistosome complex and the mechanisms by which RPW8/HR proteins trigger cell death.


Assuntos
Proteínas de Arabidopsis/imunologia , Arabidopsis/imunologia , Morte Celular , Imunidade Vegetal , Regulação da Expressão Gênica de Plantas , Plantas Geneticamente Modificadas , Multimerização Proteica , Tabaco/imunologia
3.
Nat Commun ; 11(1): 680, 2020 02 03.
Artigo em Inglês | MEDLINE | ID: mdl-32015344

RESUMO

Powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), is one of the most destructive diseases that pose a great threat to wheat production. Wheat landraces represent a rich source of powdery mildew resistance. Here, we report the map-based cloning of powdery mildew resistance gene Pm24 from Chinese wheat landrace Hulutou. It encodes a tandem kinase protein (TKP) with putative kinase-pseudokinase domains, designated WHEAT TANDEM KINASE 3 (WTK3). The resistance function of Pm24 was validated by transgenic assay, independent mutants, and allelic association analyses. Haplotype analysis revealed that a rare 6-bp natural deletion of lysine-glycine codons, endemic to wheat landraces of Shaanxi Province, China, in the kinase I domain (Kin I) of WTK3 is critical for the resistance function. Transgenic assay of WTK3 chimeric variants revealed that only the specific two amino acid deletion, rather than any of the single or more amino acid deletions, in the Kin I of WTK3 is responsible for gaining the resistance function of WTK3 against the Bgt fungus.


Assuntos
Resistência à Doença/genética , Mutação com Ganho de Função , Genes de Plantas/genética , Doenças das Plantas/microbiologia , Triticum/genética , Ascomicetos/patogenicidade , China , Peróxido de Hidrogênio/metabolismo , Mutagênese , Imunidade Vegetal/genética , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Domínios Proteicos , Proteínas Quinases/genética , Transformação Genética
4.
Science ; 367(6479): 763-768, 2020 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-32054757

RESUMO

Effector-triggered immunity (ETI), induced by host immune receptors in response to microbial effectors, protects plants against virulent pathogens. However, a systematic study of ETI prevalence against species-wide pathogen diversity is lacking. We constructed the Pseudomonas syringae Type III Effector Compendium (PsyTEC) to reduce the pan-genome complexity of 5127 unique effector proteins, distributed among 70 families from 494 strains, to 529 representative alleles. We screened PsyTEC on the model plant Arabidopsis thaliana and identified 59 ETI-eliciting alleles (11.2%) from 19 families (27.1%), with orthologs distributed among 96.8% of P. syringae strains. We also identified two previously undescribed host immune receptors, including CAR1, which recognizes the conserved effectors AvrE and HopAA1, and found that 94.7% of strains harbor alleles predicted to be recognized by either CAR1 or ZAR1.


Assuntos
Arabidopsis/imunologia , Arabidopsis/microbiologia , Interações Hospedeiro-Patógeno/imunologia , Imunidade Inata/genética , Doenças das Plantas/imunologia , Doenças das Plantas/microbiologia , Imunidade Vegetal/genética , Pseudomonas syringae/patogenicidade , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/fisiologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/imunologia , Proteínas de Transporte/genética , Proteínas de Transporte/fisiologia , Genoma de Planta , Interações Hospedeiro-Patógeno/genética , Doenças das Plantas/genética , Pseudomonas syringae/genética
5.
Nat Commun ; 11(1): 208, 2020 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-31924834

RESUMO

Microorganisms and nematodes in the rhizosphere profoundly impact plant health, and small-molecule signaling is presumed to play a central role in plant rhizosphere interactions. However, the nature of the signals and underlying mechanisms are poorly understood. Here we show that the ascaroside ascr#18, a pheromone secreted by plant-parasitic nematodes, is metabolized by plants to generate chemical signals that repel nematodes and reduce infection. Comparative metabolomics of plant tissues and excretions revealed that ascr#18 is converted into shorter side-chained ascarosides that confer repellency. An Arabidopsis mutant defective in two peroxisomal acyl-CoA oxidases does not metabolize ascr#18 and does not repel nematodes, indicating that plants, like nematodes, employ conserved peroxisomal ß-oxidation to edit ascarosides and change their message. Our results suggest that plant-editing of nematode pheromones serves as a defense mechanism that acts in parallel to conventional pattern-triggered immunity, demonstrating that plants may actively manipulate chemical signaling of soil organisms.


Assuntos
Arabidopsis/metabolismo , Arabidopsis/parasitologia , Interações Hospedeiro-Parasita/fisiologia , Nematoides/metabolismo , Feromônios/metabolismo , Acil-CoA Oxidase , Animais , Arabidopsis/imunologia , Lycopersicon esculentum , Metabolômica , Oxirredução , Doenças das Plantas/imunologia , Doenças das Plantas/parasitologia , Imunidade Vegetal , Raízes de Plantas/metabolismo , Transdução de Sinais , Triticum
6.
BMC Plant Biol ; 20(1): 5, 2020 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-31900117

RESUMO

BACKGROUND: In strawberry cultivation, continuous cropping (CC) obstacles seriously threaten production. A patented soil amendment (SA) can effectively relieve the CC obstacles to strawberry cultivation, but knowledge of the recovery mechanisms underlying this phenomenon is limited. RESULTS: In this study, transcriptomic profiling of strawberry roots in soil with and without the SA was conducted using RNA-Seq technology to reveal gene expression changes in response to SA treatment. In total, 188 differentially expressed genes (DEGs), including 144 upregulated and 44 downregulated DEGs, were identified. SA treatment resulted in genotype-dependent responses, and the response pattern, including an overall increase in the expression of nutrient transport genes and a decrease in the expression of defense response genes, may be a possible mechanism underlying recovery strategies in strawberry roots after the application of the SA to CC soil. We also found that 9 Hsp genes involved in plant defense pathways were all downregulated in the SA-treated roots. CONCLUSIONS: This research indicated that strawberry plants reallocated defense resources to development when SA treatment alleviated the stress caused by a CC soil environment. The present study provides an opportunity to reveal the fundamental mechanisms of the tradeoff between growth and defense in strawberry.


Assuntos
Fragaria/genética , Raízes de Plantas/genética , Transcriptoma/genética , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Imunidade Vegetal/genética , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Solo/química
7.
Phytopathology ; 110(3): 648-655, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31697198

RESUMO

'Candidatus Liberibacter solanacearum' is a plant pathogen affecting the families Solanaceae and Apiaceae in different parts of the world. 'Ca. L. solanacearum' is a Gram-negative, fastidious α-proteobacterium that is vectored by different psyllid species. Plant-pathogenic bacteria are known for interfering with the host physiology or defense mechanisms, often by secreting bacterial effectors. Effector proteins are critical for virulence; therefore, the identification of effectors could help with disease management. In this study, we characterized the Sec-translocon-dependent 'Ca. L. solanacearum'-hypothetical protein effector 1 (Lso-HPE1). We compared this protein sequence in the different 'Ca. L. solanacearum' haplotypes. We predicted the signal peptide and validated its function using Escherichia coli's alkaline phosphatase fusion assay. Agrobacterium tumefaciens-mediated transient expression in Nicotiana benthamiana demonstrated that Lso-HPE1 from 'Ca. L. solanacearum' haplotypes A and B were able to inhibit the induction of cell death in plants. We also compared gene expression of the Lso-HPE1- transcripts in 'Ca. L. solanacearum' haplotypes A and B in tomato and in the vector Bactericera cockerelli. This work validates the identification of a Sec-translocon-dependent 'Ca. L. solanacearum' protein possibly involved in suppression of plant cell death.


Assuntos
Hemípteros , Lycopersicon esculentum , Rhizobiaceae , Animais , Doenças das Plantas , Imunidade Vegetal
8.
Proc Natl Acad Sci U S A ; 117(3): 1799-1805, 2020 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-31852823

RESUMO

Heterotrimeric G proteins are important transducers of receptor signaling, functioning in plants with CLAVATA receptors in controlling shoot meristem size and with pathogen-associated molecular pattern receptors in basal immunity. However, whether specific members of the heterotrimeric complex potentiate cross-talk between development and defense, and the extent to which these functions are conserved across species, have not yet been addressed. Here we used CRISPR/Cas9 to knock out the maize G protein ß subunit gene (Gß) and found that the mutants are lethal, differing from those in Arabidopsis, in which homologous mutants have normal growth and fertility. We show that lethality is caused not by a specific developmental arrest, but by autoimmunity. We used a genetic diversity screen to suppress the lethal Gß phenotype and also identified a maize Gß allele with weak autoimmune responses but strong development phenotypes. Using these tools, we show that Gß controls meristem size in maize, acting epistatically with G protein α subunit gene (Gα), suggesting that Gß and Gα function in a common signaling complex. Furthermore, we used an association study to show that natural variation in Gß influences maize kernel row number, an important agronomic trait. Our results demonstrate the dual role of Gß in immunity and development in a cereal crop and suggest that it functions in cross-talk between these competing signaling networks. Therefore, modification of Gß has the potential to optimize the trade-off between growth and defense signaling to improve agronomic production.


Assuntos
Subunidades beta da Proteína de Ligação ao GTP/metabolismo , Meristema/crescimento & desenvolvimento , Imunidade Vegetal/fisiologia , Brotos de Planta/crescimento & desenvolvimento , Zea mays/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Autoimunidade/fisiologia , Sistemas CRISPR-Cas , Subunidades beta da Proteína de Ligação ao GTP/química , Subunidades beta da Proteína de Ligação ao GTP/genética , Técnicas de Inativação de Genes , Meristema/citologia , Meristema/imunologia , Fenótipo , Brotos de Planta/citologia , Brotos de Planta/imunologia , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Transdução de Sinais , Transcriptoma
9.
BMC Plant Biol ; 19(1): 579, 2019 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-31870310

RESUMO

BACKGROUND: Although it is known that resistant rootstocks facilitate management of fire blight disease, incited by Erwinia amylovora, the role of rootstock root traits in providing systemic defense against E. amylovora is unclear. In this study, the hypothesis that rootstocks of higher root vigor provide higher tolerance to fire blight infection in apples is tested. Several apple scion genotypes grafted onto a single rootstock genotype and non-grafted 'M.7' rootstocks of varying root vigor are used to assess phenotypic and molecular relationships between root traits of rootstocks and fire blight susceptibility of apple scion cultivars. RESULTS: It is observed that different root traits display significant (p < 0.05) negative correlations with fire blight susceptibility. In fact, root surface area partially dictates differential levels of fire blight susceptibility of 'M.7' rootstocks. Furthermore, contrasting changes in gene expression patterns of diverse molecular pathways accompany observed differences in levels of root-driven fire blight susceptibility. It is noted that a singular co-expression gene network consisting of genes from defense, carbohydrate metabolism, protein kinase activity, oxidation-reduction, and stress response pathways modulates root-dependent fire blight susceptibility in apple. In particular, WRKY75 and UDP-glycotransferase are singled-out as hub genes deserving of further detailed analysis. CONCLUSIONS: It is proposed that low root mass may incite resource-limiting conditions to activate carbohydrate metabolic pathways, which reciprocally interact with plant immune system genes to elicit differential levels of fire blight susceptibility.


Assuntos
Erwinia amylovora/fisiologia , Malus/fisiologia , Doenças das Plantas/microbiologia , Resistência à Doença , Genótipo , Malus/imunologia , Malus/microbiologia , Imunidade Vegetal/fisiologia , Raízes de Plantas/microbiologia , Raízes de Plantas/fisiologia
10.
BMC Plant Biol ; 19(1): 556, 2019 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-31842757

RESUMO

BACKGROUND: While virus-vector-host interactions have been a major focus of both basic and applied ecological research, little is known about how different levels of plant defense interact with prior herbivory to affect these relationships. We used genetically-modified strains of tomato (Solanum lycopersicum) varying in the jasmonic acid (JA) plant defense pathways to explore how plant defense and prior herbivory affects a plant virus (tomato yellow leaf curl virus, 'TYLCV'), its vector (the whitefly Bemisia tabaci MED), and the host. RESULTS: Virus-free MED preferred low-JA over high-JA plants and had lower fitness on high-JA plants. Viruliferous MED preferred low-JA plants but their survival was unaffected by JA levels. While virus-free MED did not lower plant JA levels, viruliferous MED decreased both JA levels and the expression of JA-related genes. Infestation by viruliferous MED reduced plant JA levels. In preference tests, neither virus-free nor viruliferous MED discriminated among JA-varying plants previously exposed to virus-free MED. However, both virus-free and viruliferous MED preferred low-JA plant genotypes when choosing between plants that had both been previously exposed to viruliferous MED. The enhanced preference for low-JA genotypes appears linked to the volatile compound neophytadiene, which was found only in whitefly-infested plants and at concentrations inversely related to plant JA levels. CONCLUSIONS: Our findings illustrate how plant defense can interact with prior herbivory to affect both a plant virus and its whitefly vector, and confirm the induction of neophytadiene by MED. The apparent attraction of MED to neophytadiene may prove useful in pest detection and management.


Assuntos
Antibiose , Begomovirus/fisiologia , Ciclopentanos/metabolismo , Hemípteros/fisiologia , Herbivoria , Lycopersicon esculentum/fisiologia , Oxilipinas/metabolismo , Doenças das Plantas/virologia , Animais , Lycopersicon esculentum/imunologia , Lycopersicon esculentum/virologia , Imunidade Vegetal , Plantas Geneticamente Modificadas/imunologia , Plantas Geneticamente Modificadas/fisiologia , Plantas Geneticamente Modificadas/virologia , Transdução de Sinais
11.
BMC Plant Biol ; 19(1): 572, 2019 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-31856725

RESUMO

BACKGROUND: During tomato cultivation, tomato leaf mould is a common disease caused by Cladosporium fulvum (C. fulvum). By encoding Cf proteins, which can recognize corresponding AVR proteins produced by C. fulvum, Cf genes provide resistance to C. fulvum, and the resistance response patterns mediated by different Cf genes are not identical. Plants carrying the Cf-19 gene show effective resistance to C. fulvum in the field and can be used as new resistant materials in breeding. In this study, to identify key regulatory genes related to resistance and to understand the resistance response process in tomato plants carrying Cf-19, RNA sequencing (RNA-seq) was used to analyse the differences between the response of resistant plants (CGN18423, carrying the Cf-19 gene) and susceptible plants (Moneymaker (MM), carrying the Cf-0 gene) at 0, 7 and 20 days after inoculation (dai). RESULTS: A total of 418 differentially expressed genes (DEGs) were identified specifically in the CGN18423 response process. Gene Ontology (GO) analysis revealed that GO terms including "plasma membrane (GO_Component)", "histidine decarboxylase activity (GO_Function)", and "carboxylic acid metabolic process (GO_Process)", as well as other 10 GO terms, were significantly enriched. The "plant hormone signal transduction" pathway, which was unique to CGN18423 in the 0-7 dai comparison, was identified. Moreover, ten key regulatory points were screened from the "plant hormone signal transduction" pathway and the "plant pathogen interaction" pathway. Hormone content measurements revealed that the salicylic acid (SA) contents increased and peaked at 7 dai, after which the contents deceased and reached minimum values in both CGN18423 and MM plants at 20 dai. The jasmonic acid (JA) content increased to a very high level at 7 dai but then decreased to nearly the initial level at 20 dai in CGN18423, while it continued to increase slightly during the whole process from 0 to 20 dai in MM. CONCLUSIONS: The initial responses are very different between the resistant and susceptible plants. The "plant hormone signal transduction" pathway is important for the formation of Cf-19-mediated immunity. In addition, both JA and SA play roles in regulating the Cf-19-dependent resistance response.


Assuntos
Cladosporium/fisiologia , Lycopersicon esculentum/genética , Doenças das Plantas/genética , Imunidade Vegetal/genética , Proteínas de Plantas/genética , Resistência à Doença/imunologia , Ontologia Genética , Lycopersicon esculentum/imunologia , Lycopersicon esculentum/microbiologia , RNA-Seq
12.
Adv Exp Med Biol ; 1209: 23-41, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31728863

RESUMO

The highly conserved catabolic process of autophagy delivers unwanted proteins or damaged organelles to vacuoles for degradation and recycling. This is essential for the regulation of cellular homeostasis, stress adaptation, and programmed cell death in eukaryotes. In particular, emerging evidence indicates that autophagy plays a multifunctional regulatory role in plant innate immunity during plant-pathogen interactions. In this review, we highlight existing knowledge regarding the involvement of autophagy in plant immunity, mechanisms functioning in the induction of autophagy upon pathogen infection, and possible directions for future research.


Assuntos
Autofagia , Imunidade Vegetal , Homeostase , Imunidade Vegetal/imunologia , Vacúolos
13.
Plant Sci ; 289: 110271, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31623793

RESUMO

Soybean cyst nematode (Heterodera glycines Ichinohe) is a sedentary root endoparasite that causes serious yield losses on soybean (Glycine max) worldwide. H. glycines secrets effector proteins into host cells to facilitate the success of parasitism. Nowadays, a large number of candidate effectors were identified from the genome sequence of H. glycines. However, the precise functions of these effectors in the nematode-host plant interaction are unknown. Here, an effector gene of dorsal gland protein Hg16B09 from H. glycines was cloned and functionally characterized through generating the transgenic soybean hairy roots. In situ hybridization assay and qRT-PCR analysis indicated Hg16B09 is exclusively expressed in the dorsal esophageal cells and up-regulated in the parasitic-stage juveniles. The constitutive expression of Hg16B09 in soybean hairy roots caused an enhanced susceptibility to H. glycines. In contrast, in planta silencing of Hg16B09 exhibited that nematode reproduction in hairy roots was decreased compared to the empty vector control. In addition, Hg16B09 also suppressed the expression of soybean defense-related genes induced by the pathogen-associated molecular pattern flg22. These data indicate that the effector Hg16B09 might aid H. glycines parasitism through suppressing plant basal defenses in the early parasitic stages.


Assuntos
Proteínas de Helminto/genética , Doenças das Plantas/imunologia , Soja/imunologia , Tylenchoidea/fisiologia , Sequência de Aminoácidos , Animais , Proteínas de Helminto/química , Proteínas de Helminto/metabolismo , Doenças das Plantas/parasitologia , Imunidade Vegetal , Alinhamento de Sequência , Soja/parasitologia , Tylenchoidea/genética
14.
Int J Mol Sci ; 20(20)2019 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-31614458

RESUMO

Small RNAs function to regulate plant defense responses to pathogens. We previously showed that miR825 and miR825* downregulate Bacillus cereus AR156 (AR156)-triggered systemic resistance to Pseudomonassyringae pv. tomato DC3000 in Arabidopsis thaliana (Arabidopsis). Here, Northern blotting revealed that miR825 and miR825* were more strongly downregulated in wild type Arabidopsis Col-0 (Col-0) plants pretreated with AR156 than in nontreated plants upon Botrytis cinerea (B. cinerea) B1301 infection. Furthermore, compared with Col-0, transgenic plants with attenuated miR825 and miR825* expression were more resistant to B. cinerea B1301, yet miR825- and miR825*-overexpressing (OE) plants were more susceptible to the pathogen. With AR156 pretreatment, the transcription of four defense-related genes (PR1, PR2, PR5, and PDF1.2) and cellular defense responses (hydrogen peroxide production and callose deposition) were faster and stronger in miR825 and miR825* knockdown lines but weaker in their OE plants than in Col-0 plants upon pathogen attack. Also, AR156 pretreatment caused stronger phosphorylation of MPK3 and MPK6 and expression of FRK1 and WRKY53 genes upon B. cinerea B1301 inoculation in miR825 and miR825* knockdown plants than in Col-0 plants. Additionally, the assay of agrobacterium-mediated transient co-expression in Nicotiana benthamiana confirmed that AT5G40910, AT5G38850, AT3G04220, and AT5G44940 are target genes of miR825 or miR825*. Compared with Col-0, the target mutant lines showed higher susceptibility to B. cinerea B1301, while still expressing AR156-triggered induced systemic resistance (ISR). The two-way analysis of variance (ANOVA) revealed a significant (P < 0.01) interactive effect of treatment and genotype on the defense responses. Hence, miR825 and miR825*act as negative regulators of AR156-mediated systemic resistance to B. cinerea B1301 in Arabidopsis.


Assuntos
Arabidopsis/crescimento & desenvolvimento , Bacillus cereus/fisiologia , Resistência à Doença , MicroRNAs/genética , Arabidopsis/genética , Arabidopsis/microbiologia , Proteínas de Arabidopsis/genética , Botrytis/patogenicidade , Regulação para Baixo , Regulação da Expressão Gênica de Plantas , Redes Reguladoras de Genes/efeitos dos fármacos , Imunidade Vegetal , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Plantas Geneticamente Modificadas/microbiologia , RNA de Plantas/genética
15.
Phytomedicine ; 64: 153081, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31568956

RESUMO

BACKGROUND: Human tumors are still a major threat to human health and plant tumors negatively affect agricultural yields. Both areas of research are developing largely independent of each other. Treatment of both plant and human tumors remains unsatisfactory and novel therapy options are urgently needed. HYPOTHESIS: The concept of this paper is to compare cellular and molecular mechanisms of tumor development in plants and human beings and to explore possibilities to develop novel treatment strategies based on bioactive secondary plant metabolites. The interdisciplinary discourse may unravel commonalities and differences in the biology of plant and human tumors as basis for rational drug development. RESULTS: Plant tumors and galls develop upon infection by bacteria (e.g. Agrobacterium tumefaciens and A. vitis, which harbor oncogenic T-DNA) and by insects (e.g. gall wasps, aphids). Plant tumors are benign, i.e. they usually do not ultimately kill their host, but they can lead to considerable economic damage due to reduced crop yields of cultivated plants. Human tumors develop by biological carcinogenesis (i.e. viruses and other infectious agents), chemical carcinogenesis (anthropogenic and non-anthropogenic environmental toxic xenobiotics) and physical carcinogenesis (radioactivity, UV-radiation). The majority of human tumors are malignant with lethal outcome. Although treatments for both plant and human tumors are available (antibiotics and apathogenic bacterial strains for plant tumors, cytostatic drugs for human tumors), treatment successes are non-satisfactory, because of drug resistance and the severe adverse side effects. In human beings, attacks by microbes are repelled by cellular immunity (i.e. innate and acquired immune systems). Plants instead display chemical defense mechanisms, whereby constitutively expressed phytoanticipin compounds compare to the innate human immune system, the acquired human immune system compares to phytoalexins, which are induced by appropriate biotic or abiotic stressors. Some chemical weapons of this armory of secondary metabolites are also active against plant galls. There is a mutual co-evolution between plant defense and animals/human beings, which was sometimes referred to as animal plant warfare. As a consequence, hepatic phase I-III metabolization and excretion developed in animals and human beings to detoxify harmful phytochemicals. On the other hand, plants invented "pro-drugs" during evolution, which are activated and toxified in animals by this hepatic biotransformation system. Recent efforts focus on phytochemicals that specifically target tumor-related mechanisms and proteins, e.g. angiogenic or metastatic inhibitors, stimulators of the immune system to improve anti-tumor immunity, specific cell death or cancer stem cell inhibitors, inhibitors of DNA damage and epigenomic deregulation, specific inhibitors of driver genes of carcinogenesis (e.g. oncogenes), inhibitors of multidrug resistance (i.e. ABC transporter efflux inhibitors), secondary metabolites against plant tumors. CONCLUSION: The exploitation of bioactive secondary metabolites to treat plant or human tumors bears a tremendous therapeutic potential. Although there are fundamental differences between human and plant tumors, either isolated phytochemicals and their (semi)synthetic derivatives or chemically defined and standardized plant extracts may offer new therapy options to decrease human tumor incidence and mortality as well as to increase agricultural yields by fighting crown galls.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Neoplasias/etiologia , Doenças das Plantas/etiologia , Fenômenos Fisiológicos Vegetais , Plantas/metabolismo , Agrobacterium tumefaciens/patogenicidade , Animais , Antibióticos Antineoplásicos/farmacologia , Resistencia a Medicamentos Antineoplásicos , Humanos , Neoplasias/tratamento farmacológico , Compostos Fitoquímicos , Imunidade Vegetal , Plantas/microbiologia , Metabolismo Secundário
16.
Plant Mol Biol ; 101(4-5): 343-354, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31621005

RESUMO

KEY MESSAGE: Short review focussing on the role and targeting of vacuolar substructure in plant immunity and pathogenesis. Plants lack specialized immune cells, therefore each plant cell must defend itself against invading pathogens. A typical plant defense strategy is the hypersensitive response that results in host cell death at the site of infection, a process largely regulated by the vacuole. In plant cells, the vacuole is a vital organelle that plays a central role in numerous fundamental processes, such as development, reproduction, and cellular responses to biotic and abiotic stimuli. It shows divergent membranous structures that are continuously transforming. Recent technical advances in visualization and live-cell imaging have significantly altered our view of the vacuolar structures and their dynamics. Understanding the active nature of the vacuolar structures and the mechanisms of vacuole-mediated defense responses is of great importance in understanding plant-pathogen interactions. In this review, we present an overview of the current knowledge about the vacuole and its internal structures, as well as their role in plant-microbe interactions. There is so far limited information on the modulation of the vacuolar structures by pathogens, but recent research has identified the vacuole as a possible target of microbial interference.


Assuntos
Interações Hospedeiro-Patógeno , Imunidade Vegetal , Plantas/ultraestrutura , Vacúolos/ultraestrutura , Biomarcadores/metabolismo , Morte Celular , Membranas Intracelulares/imunologia , Membranas Intracelulares/microbiologia , Membranas Intracelulares/ultraestrutura , Proteínas de Plantas/metabolismo , Plantas/imunologia , Plantas/microbiologia , Vacúolos/imunologia , Vacúolos/microbiologia
17.
Plant Physiol Biochem ; 144: 466-479, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31655345

RESUMO

Pyricularia oryzae (P. oryzae), one of the most devastating fungal pathogens, is the cause of blast disease in rice. Infection with a blast fungus induces biological responses in the host plant that lead to its survival through the termination or suppression of pathogen growth, and metabolite compounds play vital roles in plant interactions with a wide variety of other organisms. Numerous studies have indicated that rice has a multi-layered plant immune system that includes pre-developed (e.g., cell wall and phytoanticipins), constitutive and inducible (phytoalexins) defence barriers against stresses. Significant progress towards understanding the basis of the molecular mechanisms underlying the defence responses of rice to P. oryzae has been achieved. Nonetheless, even though the important metabolites in the responses of rice to pathogens have been identified, their exact mechanisms and their contributions to plant immunity against blast fungi have not been elucidated. The purpose of this review is to summarize and discuss recent advances towards the understanding of the integrated metabolite variations in rice after P. oryzae invasion.


Assuntos
Oryza/metabolismo , Oryza/microbiologia , Adaptação Fisiológica , Interações Hospedeiro-Patógeno , Magnaporthe/patogenicidade , Doenças das Plantas/microbiologia , Imunidade Vegetal
18.
BMC Plant Biol ; 19(1): 450, 2019 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-31655554

RESUMO

BACKGROUND: Secondary metabolites play an important role in the plant defensive response. They are produced as a defence mechanism against biotic stress by providing plants with antimicrobial and antioxidant weapons. In higher plants, the majority of secondary metabolites accumulate as glycoconjugates. Glycosylation is one of the commonest modifications of secondary metabolites, and is carried out by enzymes called glycosyltransferases. RESULTS: Here we provide evidence that the previously described tomato wound and pathogen-induced glycosyltransferase Twi1 displays in vitro activity toward the coumarins scopoletin, umbelliferone and esculetin, and the flavonoids quercetin and kaempferol, by uncovering a new role of this gene in plant glycosylation. To test its activity in vivo, Twi1-silenced transgenic tomato plants were generated and infected with Tomato spotted wilt virus. The Twi1-silenced plants showed a differential accumulation of Twi1 substrates and enhanced susceptibility to the virus. CONCLUSIONS: Biochemical in vitro assays and transgenic plants generation proved to be useful strategies to assign a role of tomato Twi1 in the plant defence response. Twi1 glycosyltransferase showed to regulate quercetin and kaempferol levels in tomato plants, affecting plant resistance to viral infection.


Assuntos
Cumarínicos/metabolismo , Flavonoides/metabolismo , Glicosiltransferases/metabolismo , Lycopersicon esculentum/enzimologia , Doenças das Plantas/imunologia , Tospovirus/patogenicidade , Regulação da Expressão Gênica de Plantas , Glicosilação , Glicosiltransferases/genética , Lycopersicon esculentum/genética , Lycopersicon esculentum/imunologia , Lycopersicon esculentum/virologia , Doenças das Plantas/virologia , Imunidade Vegetal , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo
19.
Nat Commun ; 10(1): 4810, 2019 10 22.
Artigo em Inglês | MEDLINE | ID: mdl-31641112

RESUMO

Systemic acquired resistance (SAR) is a long-lasting broad-spectrum plant immunity induced by mobile signals produced in the local leaves where the initial infection occurs. Although multiple structurally unrelated signals have been proposed, the mechanisms responsible for perception of these signals in the systemic leaves are unknown. Here, we show that exogenously applied nicotinamide adenine dinucleotide (NAD+) moves systemically and induces systemic immunity. We demonstrate that the lectin receptor kinase (LecRK), LecRK-VI.2, is a potential receptor for extracellular NAD+ (eNAD+) and NAD+ phosphate (eNADP+) and plays a central role in biological induction of SAR. LecRK-VI.2 constitutively associates with BRASSINOSTEROID INSENSITIVE1-ASSOCIATED KINASE1 (BAK1) in vivo. Furthermore, BAK1 and its homolog BAK1-LIKE1 are required for eNAD(P)+ signaling and SAR, and the kinase activities of LecR-VI.2 and BAK1 are indispensable to their function in SAR. Our results indicate that eNAD+ is a putative mobile signal, which triggers SAR through its receptor complex LecRK-VI.2/BAK1 in Arabidopsis thaliana.


Assuntos
Proteínas de Arabidopsis/imunologia , Arabidopsis/imunologia , NAD/imunologia , Doenças das Plantas/imunologia , Proteínas Serina-Treonina Quinases/imunologia , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Resistência à Doença , Regulação da Expressão Gênica de Plantas , Doenças das Plantas/microbiologia , Imunidade Vegetal , Ligação Proteica , Proteínas Serina-Treonina Quinases/genética , Pseudomonas syringae/fisiologia
20.
Int J Mol Sci ; 20(18)2019 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-31533258

RESUMO

Eukaryotic genes are packed into a dynamic but stable nucleoprotein structure called chromatin. Chromatin-remodeling and modifying complexes generate a dynamic chromatin environment that ensures appropriate DNA processing and metabolism in various processes such as gene expression, as well as DNA replication, repair, and recombination. The INO80 and SWR1 chromatin remodeling complexes (INO80-c and SWR1-c) are ATP-dependent complexes that modulate the incorporation of the histone variant H2A.Z into nucleosomes, which is a critical step in eukaryotic gene regulation. Although SWR1-c has been identified in plants, plant INO80-c has not been successfully isolated and characterized. In this review, we will focus on the functions of the SWR1-c and putative INO80-c (SWR1/INO80-c) multi-subunits and multifunctional complexes in Arabidopsis thaliana. We will describe the subunit compositions of the SWR1/INO80-c and the recent findings from the standpoint of each subunit and discuss their involvement in regulating development and environmental responses in Arabidopsis.


Assuntos
ATPases Associadas a Diversas Atividades Celulares/metabolismo , Montagem e Desmontagem da Cromatina , Proteínas de Ligação a DNA/metabolismo , Substâncias Macromoleculares/metabolismo , Plantas/metabolismo , Cromatina/genética , Cromatina/metabolismo , Reparo do DNA , Replicação do DNA , Histonas/metabolismo , MicroRNAs/genética , Desenvolvimento Vegetal , Imunidade Vegetal , Plantas/genética
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