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1.
Plant J ; 110(6): 1791-1810, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35411592

RESUMO

Wild relatives of tomato are a valuable source of natural variation in tomato breeding, as many can be hybridized to the cultivated species (Solanum lycopersicum). Several, including Solanum lycopersicoides, have been crossed to S. lycopersicum for the development of ordered introgression lines (ILs), facilitating breeding for desirable traits. Despite the utility of these wild relatives and their associated ILs, few finished genome sequences have been produced to aid genetic and genomic studies. Here we report a chromosome-scale genome assembly for S. lycopersicoides LA2951, which contains 37 938 predicted protein-coding genes. With the aid of this genome assembly, we have precisely delimited the boundaries of the S. lycopersicoides introgressions in a set of S. lycopersicum cv. VF36 × LA2951 ILs. We demonstrate the usefulness of the LA2951 genome by identifying several quantitative trait loci for phenolics and carotenoids, including underlying candidate genes, and by investigating the genome organization and immunity-associated function of the clustered Pto gene family. In addition, syntenic analysis of R2R3MYB genes sheds light on the identity of the Aubergine locus underlying anthocyanin production. The genome sequence and IL map provide valuable resources for studying fruit nutrient/quality traits, pathogen resistance, and environmental stress tolerance. We present a new genome resource for the wild species S. lycopersicoides, which we use to shed light on the Aubergine locus responsible for anthocyanin production. We also provide IL boundary mappings, which facilitated identifying novel carotenoid quantitative trait loci of which one was likely driven by an uncharacterized lycopene ß-cyclase whose function we demonstrate.


Assuntos
Solanum lycopersicum , Solanum , Antocianinas/genética , Cromossomos de Plantas/genética , Solanum lycopersicum/genética , Melhoramento Vegetal , Solanum/genética
2.
Mol Plant Microbe Interact ; 35(2): 157-169, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34732057

RESUMO

Increasingly, new evidence has demonstrated variability in the epitope regions of bacterial flagellin, including in regions harboring the microbe-associated molecular patterns flg22 and flgII-28 that are recognized by the pattern recognition receptors FLS2 and FLS3, respectively. Additionally, because bacterial motility is known to contribute to pathogen virulence and chemotaxis, reductions in or loss of motility can significantly reduce bacterial fitness. In this study, we determined that variations in flg22 and flgII-28 epitopes allow some but not all Xanthomonas spp. to evade both FLS2- and FLS3-mediated oxidative burst responses. We observed variation in the motility for many isolates, regardless of their flagellin sequence. Instead, we determined that past growth conditions may have a significant impact on the motility status of isolates, because we could minimize this variability by inducing motility using chemoattractant assays. Additionally, motility could be significantly suppressed under nutrient-limited conditions, and bacteria could "remember" its prior motility status after storage at ultracold temperatures. Finally, we observed larger bacterial populations of strains with flagellin variants predicted not to be recognized by either FLS2 or FLS3, suggesting that these bacteria can evade flagellin recognition in tomato plants. Although some flagellin variants may impart altered motility and differential recognition by the host immune system, external growth parameters and gene expression regulation appear to have more significant impacts on the motility phenotypes for these Xanthomonas spp.[Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Xanthomonas , Arabidopsis/microbiologia , Proteínas de Arabidopsis/metabolismo , Flagelina , Regulação da Expressão Gênica , Polimorfismo Genético , Proteínas Quinases/metabolismo , Xanthomonas/genética , Xanthomonas/metabolismo
3.
Plant Physiol ; 183(4): 1825-1837, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32503903

RESUMO

Plants mount defense responses by recognizing indicators of pathogen invasion, including microbe-associated molecular patterns (MAMPs). Flagellin, from the bacterial pathogen Pseudomonas syringae pv. tomato (Pst), contains two MAMPs, flg22 and flgII-28, that are recognized by tomato (Solanum lycopersicum) receptors Flagellin sensing2 (Fls2) and Fls3, respectively, but to what degree each receptor contributes to immunity and whether they promote immune responses using the same molecular mechanisms are unknown. Here, we characterized CRISPR/Cas9-generated Fls2 and Fls3 tomato mutants and found that the two receptors contribute equally to disease resistance both on the leaf surface and in the apoplast. However, we observed striking differences in certain host responses mediated by the two receptors. Compared to Fls2, Fls3 mediated a more sustained production of reactive oxygen species and an increase in transcript abundance of 44 tomato genes, with two genes serving as specific reporters for the Fls3 pathway. Fls3 had greater in vitro kinase activity than Fls2 and could transphosphorylate a substrate. Using chimeric Fls2/Fls3 proteins, we found no evidence that a single receptor domain is responsible for the Fls3-sustained reactive oxygen species, suggesting involvement of multiple structural features or a nullified function of the chimeric construct. This work reveals differences in certain immunity outputs between Fls2 and Fls3, suggesting that they might use distinct molecular mechanisms to activate pattern-triggered immunity in response to flagellin-derived MAMPs.


Assuntos
Solanum lycopersicum/metabolismo , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Flagelina/metabolismo , Doenças das Plantas , Imunidade Vegetal/fisiologia , Proteínas Quinases/metabolismo , Pseudomonas syringae/patogenicidade
4.
Phytopathology ; 111(8): 1289-1300, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33734871

RESUMO

Bacterial leaf spot disease caused by Xanthomonas cucurbitae has severely affected the pumpkin industries in the Midwestern region of United States, with the bacteria mainly infecting pumpkin leaves and fruits, and leading to significant yield losses. In this study, we utilized genomics and genetics approaches to elucidate X. cucurbitae molecular mechanisms of pathogenesis during interaction with its host. We generated the first reference-quality whole-genome sequence of the X. cucurbitae type isolate and compared with other Xanthomonas species, X. cucurbitae has a smaller genome size with fewer virulence-related genes. RNA-seq analysis of X. cucurbitae under plant-mimicking media conditions showed altered transcriptional responses, with upregulation of virulence genes and downregulation of cellular homeostasis genes. Additionally, characterization of key virulence genes using gene deletion methods revealed that both type II enzymes and type III effectors are necessary for X. cucurbitae to cause infection in the pumpkin host.


Assuntos
Doenças das Plantas , Xanthomonas , Proteínas de Bactérias/genética , Sequência de Bases , Genoma Bacteriano/genética , Genômica , Xanthomonas/genética
5.
J Chem Ecol ; 46(3): 330-343, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31989490

RESUMO

Plants perceive insect herbivores via a sophisticated surveillance system that detects a range of alarm signals, including herbivore-associated molecular patterns (HAMPs). Fatty acid-amino acid conjugates (FACs) are HAMPs present in oral secretions (OS) of lepidopteran larvae that induce defense responses in many plant species. In contrast to eggplant (Solanum melongena), tomato (S. lycopersicum) does not respond to FACs present in OS from Manduca sexta (Lepidoptera). Since both plants are found in the same genus, we tested whether loss of sensitivity to FACs in tomato may be a domestication effect. Using highly sensitive MAP kinase (MAPK) phosphorylation assays, we demonstrate that four wild tomato species and the closely related potato (S. tuberosum) do not respond to the FACs N-linolenoyl-L-glutamine and N-linolenoyl-L-glutamic acid, excluding a domestication effect. Among other genera within the Solanaceae, we found that bell pepper (Capsicum annuum) is responsive to FACs, while there is a differential responsiveness to FACs among tobacco (Nicotiana) species, ranging from strong responsiveness in N. benthamiana to no responsiveness in N. knightiana. The Petunia lineage is one of the oldest lineages within the Solanaceae and P. hybrida was responsive to FACs. Collectively, we demonstrate that plant responsiveness to FACs does not follow simple phylogenetic relationships in the family Solanaceae. Instead, sensitivity to FACs is a dynamic ancestral trait present in monocots and eudicots that was repeatedly lost during the evolution of Solanaceae species. Although tomato is insensitive to FACs, we found that other unidentified factors in M. sexta OS induce defenses in tomato.


Assuntos
Aminoácidos/metabolismo , Antibiose , Ácidos Graxos/metabolismo , Herbivoria , Manduca/fisiologia , Solanaceae/fisiologia , Animais , Larva , Especificidade da Espécie
6.
Mol Plant Microbe Interact ; 32(11): 1496-1507, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31251114

RESUMO

The molecular mechanisms acting between host recognition of pathogen effectors by nucleotide-binding leucine-rich repeat receptor (NLR) proteins and mitogen-activated protein kinase (MAPK) signaling cascades are unknown. MAPKKKα (M3Kα) activates MAPK signaling leading to programmed cell death (PCD) associated with NLR-triggered immunity. We identified a tomato M3Kα-interacting protein, SlMai1, that has 80% amino acid identity with Arabidopsis brassinosteroid kinase 1 (AtBsk1). SlMai1 has a protein kinase domain and a C-terminal tetratricopeptide repeat domain that interacts with the kinase domain of M3Kα. Virus-induced gene silencing of Mai1 homologs in Nicotiana benthamiana increased susceptibility to Pseudomonas syringae and compromised PCD induced by four NLR proteins. PCD was restored by expression of a synthetic SlMai1 gene that resists silencing. Expression of AtBsk1 did not restore PCD in Mai1-silenced plants, suggesting SlMai1 is functionally divergent from AtBsk1. PCD caused by overexpression of M3Kα or MKK2 was unaffected by Mai1 silencing, suggesting Mai1 acts upstream of these proteins. Coexpression of Mai1 with M3Kα in leaves enhanced MAPK phosphorylation and accelerated PCD. These findings suggest Mai1 is a molecular link acting between host recognition of pathogens and MAPK signaling.


Assuntos
Interações Hospedeiro-Patógeno , Proteínas Quinases Ativadas por Mitógeno , Doenças das Plantas , Transdução de Sinais , Interações Hospedeiro-Patógeno/fisiologia , Solanum lycopersicum/enzimologia , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Doenças das Plantas/imunologia , Doenças das Plantas/microbiologia , Proteínas de Plantas/metabolismo , Pseudomonas syringae/enzimologia , Nicotiana/enzimologia
7.
Mol Plant Microbe Interact ; 32(8): 949-960, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30785360

RESUMO

Race 1 strains of Pseudomonas syringae pv. tomato, which cause bacterial speck disease of tomato, are becoming increasingly common and no simply inherited genetic resistance to such strains is known. We discovered that a locus in Solanum lycopersicoides, termed Pseudomonas tomato race 1 (Ptr1), confers resistance to race 1 P. syringae pv. tomato strains by detecting the activity of type III effector AvrRpt2. In Arabidopsis, AvrRpt2 degrades the RIN4 protein, thereby activating RPS2-mediated immunity. Using site-directed mutagenesis of AvrRpt2, we found that, like RPS2, activation of Ptr1 requires AvrRpt2 proteolytic activity. Ptr1 also detected the activity of AvrRpt2 homologs from diverse bacteria, including one in Ralstonia pseudosolanacearum. The genome sequence of S. lycopersicoides revealed no RPS2 homolog in the Ptr1 region. Ptr1 could play an important role in controlling bacterial speck disease and its future cloning may shed light on an example of convergent evolution for recognition of a widespread type III effector.


Assuntos
Resistência à Doença , Proteínas de Membrana Transportadoras , Pseudomonas syringae , Ralstonia , Solanum , Proteínas de Bactérias/metabolismo , Resistência à Doença/genética , Genoma Bacteriano/genética , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Pseudomonas syringae/classificação , Pseudomonas syringae/fisiologia , Ralstonia/classificação , Ralstonia/fisiologia , Solanum/genética , Solanum/microbiologia
8.
New Phytol ; 223(1): 447-461, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-30861136

RESUMO

The interaction between tomato and Pseudomonas syringae pv tomato (Pst) is a well-developed model for investigating the molecular basis of the plant immune system. There is extensive natural variation in Solanum lycopersicum (tomato) but it has not been fully leveraged to enhance our understanding of the tomato-Pst pathosystem. We screened 216 genetically diverse accessions of cultivated tomato and a wild tomato species for natural variation in their response to three strains of Pst. The host response to Pst was investigated using multiple Pst strains, tomato accessions with available genome sequences, reactive oxygen species (ROS) assays, reporter genes and bacterial population measurements. The screen uncovered a broad range of previously unseen host symptoms in response to Pst, and one of these, stem galls, was found to be simply inherited. The screen also identified tomato accessions that showed enhanced responses to flagellin in bacterial population assays and in ROS assays upon exposure to flagellin-derived peptides, flg22 and flgII-28. Reporter genes confirmed that the host responses were due primarily to pattern recognition receptor-triggered immunity. This study revealed extensive natural variation in tomato for susceptibility and resistance to Pst and will enable elucidation of the molecular mechanisms underlying these host responses.


Assuntos
Ecótipo , Flagelina/metabolismo , Variação Genética , Interações Hospedeiro-Patógeno/imunologia , Imunidade Vegetal , Pseudomonas syringae/fisiologia , Solanum lycopersicum/imunologia , Solanum lycopersicum/microbiologia , Resistência à Doença , Genes Reporter , Padrões de Herança/genética , Solanum lycopersicum/genética , Mutação/genética , Peptídeos/metabolismo , Fenótipo , Doenças das Plantas/imunologia , Doenças das Plantas/microbiologia , Folhas de Planta/fisiologia , Tumores de Planta/microbiologia , Característica Quantitativa Herdável , Espécies Reativas de Oxigênio/metabolismo
9.
J Exp Bot ; 69(3): 643-654, 2018 01 23.
Artigo em Inglês | MEDLINE | ID: mdl-29240956

RESUMO

Plant responses to the environment and developmental processes are mediated by a complex signaling network. The Arabidopsis thaliana mitogen-activated protein kinases (MAPKs) MPK3 and MPK6 and their orthologs in other plants are shared signal transducers that respond to many developmental and environmental signals and thus represent highly connected hubs in the cellular signaling network. In animals, specific MAPK signaling complexes are assembled which enable input-specific protein-protein interactions and thus specific signaling outcomes. In plants, not much is known about such signaling complexes. Here, we report that MPK3, MPK6, and MPK10 orthologs in tomato, tobacco, and Arabidopsis as well as tomato MAPK kinase 4 (MKK4) associate with high molecular weight (~250-550 kDa) multiprotein complexes. Elicitation by the defense-associated peptides flg22 and systemin resulted in phosphorylation and activation of the monomeric MAPKs, whereas the complex-associated MAPKs remained unphosphorylated and inactive. In contrast, treatment of tomato cells with a phosphatase inhibitor resulted in association of phosphorylated MPK1/2 with the complex. These results demonstrate that plant MAPKs and MAPKKs dynamically assemble into stable multiprotein complexes and this may depend on their phosphorylation status. Identification of the constituents of these multiprotein complexes promises a deeper understanding of signaling dynamics.


Assuntos
Arabidopsis/genética , Regulação da Expressão Gênica de Plantas , Proteínas Quinases Ativadas por Mitógeno/genética , Proteínas de Plantas/genética , Arabidopsis/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Peso Molecular , Complexos Multiproteicos , Proteínas de Plantas/metabolismo
10.
Mol Plant Pathol ; 25(3): e13445, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38528659

RESUMO

The pattern-triggered immunity (PTI) response is triggered at the plant cell surface by the recognition of microbe-derived molecules known as microbe- or pathogen-associated molecular patterns or molecules derived from compromised host cells called damage-associated molecular patterns. Membrane-localized receptor proteins, known as pattern recognition receptors, are responsible for this recognition. Although much of the machinery of PTI is conserved, natural variation for the PTI response exists within and across species with respect to the components responsible for pattern recognition, activation of the response, and the strength of the response induced. This review describes what is known about this variation. We discuss how variation in the PTI response can be measured and how this knowledge might be utilized in the control of plant disease and in developing plant varieties with enhanced disease resistance.


Assuntos
Reconhecimento da Imunidade Inata , Imunidade Vegetal , Imunidade Vegetal/fisiologia , Plantas , Resistência à Doença , Doenças das Plantas , Receptores de Reconhecimento de Padrão
11.
New Phytol ; 200(3): 847-860, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23865782

RESUMO

The bacterial flagellin (FliC) epitopes flg22 and flgII-28 are microbe-associated molecular patterns (MAMPs). Although flg22 is recognized by many plant species via the pattern recognition receptor FLS2, neither the flgII-28 receptor nor the extent of flgII-28 recognition by different plant families is known. Here, we tested the significance of flgII-28 as a MAMP and the importance of allelic diversity in flg22 and flgII-28 in plant-pathogen interactions using purified peptides and a Pseudomonas syringae ∆fliC mutant complemented with different fliC alleles. The plant genotype and allelic diversity in flg22 and flgII-28 were found to significantly affect the plant immune response, but not bacterial motility. The recognition of flgII-28 is restricted to a number of solanaceous species. Although the flgII-28 peptide does not trigger any immune response in Arabidopsis, mutations in both flg22 and flgII-28 have FLS2-dependent effects on virulence. However, the expression of a tomato allele of FLS2 does not confer to Nicotiana benthamiana the ability to detect flgII-28, and tomato plants silenced for FLS2 are not altered in flgII-28 recognition. Therefore, MAMP diversification is an effective pathogen virulence strategy, and flgII-28 appears to be perceived by an as yet unidentified receptor in the Solanaceae, although it has an FLS2-dependent virulence effect in Arabidopsis.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/microbiologia , Flagelina/genética , Genótipo , Imunidade Vegetal/genética , Proteínas Quinases/metabolismo , Pseudomonas syringae/patogenicidade , Solanaceae/microbiologia , Alelos , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Regulação da Expressão Gênica de Plantas , Interações Hospedeiro-Patógeno/genética , Solanum lycopersicum/genética , Solanum lycopersicum/metabolismo , Solanum lycopersicum/microbiologia , Mutação , Doenças das Plantas/genética , Proteínas Quinases/genética , Pseudomonas syringae/genética , Pseudomonas syringae/fisiologia , Solanaceae/genética , Solanaceae/metabolismo , Nicotiana/genética , Nicotiana/metabolismo , Nicotiana/microbiologia
12.
Plant J ; 65(3): 480-91, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21265900

RESUMO

The COP9 signalosome (CSN) is a multi-protein complex that regulates the activities of cullin-RING E3 ubiquitin ligases (CRLs). CRLs ubiquitinate proteins in order to target them for proteasomal degradation. The CSN is required for proper plant development. Here we show that the CSN also has a profound effect on plant defense responses. Silencing of genes for CSN subunits in tomato plants resulted in a mild morphological phenotype and reduced expression of wound-responsive genes in response to mechanical wounding, attack by Manduca sexta larvae, and Prosystemin over-expression. In contrast, expression of pathogenesis-related genes was increased in a stimulus-independent manner in these plants. The reduced wound response in CSN-silenced plants corresponded with reduced synthesis of jasmonic acid (JA), but levels of salicylic acid (SA) were unaltered. As a consequence, these plants exhibited reduced resistance against herbivorous M. sexta larvae and the necrotrophic fungal pathogen Botrytis cinerea. In contrast, susceptibility to tobacco mosaic virus (TMV) was not altered in CSN-silenced plants. These data demonstrate that the CSN orchestrates not only plant development but also JA-dependent plant defense responses.


Assuntos
Ciclopentanos/metabolismo , Complexos Multiproteicos/fisiologia , Oxilipinas/metabolismo , Peptídeo Hidrolases/fisiologia , Imunidade Vegetal/genética , Proteínas de Plantas/fisiologia , Solanum lycopersicum/fisiologia , Animais , Botrytis/imunologia , Botrytis/patogenicidade , Complexo do Signalossomo COP9 , Ciclopentanos/análise , Regulação da Expressão Gênica de Plantas/imunologia , Inativação Gênica , Solanum lycopersicum/genética , Solanum lycopersicum/microbiologia , Solanum lycopersicum/parasitologia , Manduca/imunologia , Manduca/patogenicidade , Complexos Multiproteicos/genética , Oxilipinas/análise , Peptídeo Hidrolases/genética , Fenótipo , Doenças das Plantas , Proteínas de Plantas/genética , Ácido Salicílico/análise , Ácido Salicílico/metabolismo , Vírus do Mosaico do Tabaco/imunologia , Vírus do Mosaico do Tabaco/patogenicidade , Ferimentos e Lesões
13.
Pilot Feasibility Stud ; 8(1): 206, 2022 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-36088457

RESUMO

BACKGROUND: Approximately 15 million people in the UK live with obesity, around 5 million of whom have severe obesity (body mass index (BMI) ≥35kg/m2). Having severe obesity markedly compromises health, well-being and quality of life, and substantially reduces life expectancy. These adverse outcomes are prevented or ameliorated by weight loss, for which sustained behavioural change is the cornerstone of treatment. Although NHS specialist 'Tier 3' Weight Management Services (T3WMS) support people with severe obesity, using individual and group-based treatment, the current evidence on optimal intervention design and outcomes is limited. Due to heterogeneity of severe obesity, there is a need to tailor treatment to address individual needs. Despite this heterogeneity, there are good reasons to suspect that a structured group-based behavioural intervention may be more effective and cost-effective for the treatment of severe obesity compared to usual care. The aims of this study are to test the feasibility of establishing and delivering a multi-centre randomised controlled clinical trial to compare a group-based behavioural intervention versus usual care in people with severe obesity. METHODS: This feasibility randomised controlled study is a partially clustered multi-centre trial of PROGROUP (a novel group-based behavioural intervention) versus usual care. Adults ≥18 years of age who have been newly referred to and accepted by NHS T3WMS will be eligible if they have a BMI ≥40, or ≥35 kg/m2 with comorbidity, are suitable for group-based care and are willing to be randomised. Exclusion criteria are participation in another weight management study, planned bariatric surgery during the trial, and unwillingness or inability to attend group sessions. Outcome assessors will be blinded to treatment allocation and success of blinding will be evaluated. Clinical measures will be collected at baseline, 6 and 12 months post-randomisation. Secondary outcome measures will be self-reported and collected remotely. Process and economic evaluations will be conducted. DISCUSSION: This randomised feasibility study has been designed to test all the required research procedures and additionally explore three key issues; the feasibility of implementing a complex trial at participating NHS T3WMS, training the multidisciplinary healthcare teams in a standard intervention, and the acceptability of a group intervention for these particularly complex patients. TRIAL REGISTRATION: ISRCTN number 22088800.

14.
Curr Protoc Plant Biol ; 2: 240-269, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-29098191

RESUMO

The field of plant receptor biology has rapidly expanded in recent years, however the demonstration of direct interaction between receptor-ligand pairs remains a challenge. Click chemistry has revolutionized small molecule research but lacks popularity in plant research. Here we describe a method that tests for the direct physical interaction of a candidate receptor protein and a peptide ligand. This protocol describes the generation of the ligand probe, transient expression of a receptor protein, enrichment of membrane-bound receptors, photo-crosslinking and click chemistry-mediated reporter addition, and detection of the receptor-ligand complex. Copper-based click chemistry confers several advantages, including the versatility to use almost any azide-containing reporter molecule for detection or visualization of the complex and addition of the reporter molecule after receptor-ligand binding which reduces the need for bulky ligand modifications that could interfere with the interaction.


Assuntos
Química Click/métodos , Peptídeos/metabolismo , Receptores de Peptídeos/metabolismo , Azidas/química , Cobre/química , Genes Reporter , Ligantes , Proteínas de Plantas/metabolismo , Ligação Proteica
15.
Plant Methods ; 12: 38, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27493678

RESUMO

BACKGROUND: The plant plasma membrane is a key battleground in the war between plants and their pathogens. Plants detect the presence of pathogens at the plasma membrane using sensor proteins, many of which are targeted to this lipophilic locale by way of fatty acid modifications. Pathogens secrete effector proteins into the plant cell to suppress the plant's defense mechanisms. These effectors are able to access and interfere with the surveillance machinery at the plant plasma membrane by hijacking the host's fatty acylation apparatus. Despite the important involvement of protein fatty acylation in both plant immunity and pathogen virulence mechanisms, relatively little is known about the role of this modification during plant-pathogen interactions. This dearth in our understanding is due largely to the lack of methods to monitor protein fatty acid modifications in the plant cell. RESULTS: We describe a rapid method to detect two major forms of fatty acylation, N-myristoylation and S-acylation, of candidate proteins using alkyne fatty acid analogs coupled with click chemistry. We applied our approach to confirm and decisively demonstrate that the archetypal pattern recognition receptor FLS2, the well-characterized pathogen effector AvrPto, and one of the best-studied intracellular resistance proteins, Pto, all undergo plant-mediated fatty acylation. In addition to providing a means to readily determine fatty acylation, particularly myristoylation, of candidate proteins, this method is amenable to a variety of expression systems. We demonstrate this using both Arabidopsis protoplasts and stable transgenic Arabidopsis plants and we leverage Agrobacterium-mediated transient expression in Nicotiana benthamiana leaves as a means for high-throughput evaluation of candidate proteins. CONCLUSIONS: Protein fatty acylation is a targeting tactic employed by both plants and their pathogens. The metabolic labeling approach leveraging alkyne fatty acid analogs and click chemistry described here has the potential to provide mechanistic details of the molecular tactics used at the host plasma membrane in the battle between plants and pathogens.

16.
Nat Plants ; 2: 16128, 2016 08 22.
Artigo em Inglês | MEDLINE | ID: mdl-27548463

RESUMO

Plants and animals detect the presence of potential pathogens through the perception of conserved microbial patterns by cell surface receptors. Certain solanaceous plants, including tomato, potato and pepper, detect flgII-28, a region of bacterial flagellin that is distinct from that perceived by the well-characterized FLAGELLIN-SENSING 2 receptor. Here we identify and characterize the receptor responsible for this recognition in tomato, called FLAGELLIN-SENSING 3. This receptor binds flgII-28 and enhances immune responses leading to a reduction in bacterial colonization of leaf tissues. Further characterization of FLS3 and its signalling pathway could provide new insights into the plant immune system and transfer of the receptor to other crop plants offers the potential of enhancing resistance to bacterial pathogens that have evolved to evade FLS2-mediated immunity.


Assuntos
Flagelina/metabolismo , Imunidade Vegetal , Proteínas de Plantas/genética , Proteínas Quinases/genética , Solanum lycopersicum/genética , Solanum lycopersicum/imunologia , Solanum lycopersicum/microbiologia , Folhas de Planta/imunologia , Folhas de Planta/microbiologia , Proteínas de Plantas/metabolismo , Proteínas Quinases/metabolismo , Transdução de Sinais
17.
PLoS One ; 9(9): e106119, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25180693

RESUMO

Tomato (Solanum lycopersicum L.) is susceptible to many diseases including bacterial speck caused by Pseudomonas syringae pv. tomato. Bacterial speck disease is a serious problem worldwide in tomato production areas where moist conditions and cool temperatures occur. To enhance breeding of speck resistant fresh-market tomato cultivars we identified a race 0 field isolate, NC-C3, of P. s. pv. tomato in North Carolina and used it to screen a collection of heirloom tomato lines for speck resistance in the field. We observed statistically significant variation among the heirloom tomatoes for their response to P. s. pv. tomato NC-C3 with two lines showing resistance approaching a cultivar that expresses the Pto resistance gene, although none of the heirloom lines have Pto. Using an assay that measures microbe-associated molecular pattern (MAMP)-induced production of reactive oxygen species (ROS), we investigated whether the heirloom lines showed differential responsiveness to three bacterial-derived peptide MAMPs: flg22 and flgII-28 (from flagellin) and csp22 (from cold shock protein). Significant differences were observed for MAMP responsiveness among the lines, although these differences did not correlate strongly with resistance or susceptibility to bacterial speck disease. The identification of natural variation for MAMP responsiveness opens up the possibility of using a genetic approach to identify the underlying loci and to facilitate breeding of cultivars with enhanced disease resistance. Towards this goal, we discovered that responsiveness to csp22 segregates as a single locus in an F2 population of tomato.


Assuntos
Flagelina/metabolismo , Variação Genética , Pseudomonas syringae/patogenicidade , Solanum lycopersicum/genética , Solanum lycopersicum/microbiologia , Aminoácidos/biossíntese , Proteínas de Bactérias/metabolismo , Resistência à Doença/imunologia , Genes Bacterianos , Indenos , Solanum lycopersicum/imunologia , North Carolina , Filogenia , Doenças das Plantas/imunologia , Doenças das Plantas/microbiologia , Pseudomonas syringae/genética , Pseudomonas syringae/isolamento & purificação , Receptores de Reconhecimento de Padrão/metabolismo
18.
Plant Sci ; 180(5): 686-93, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21421419

RESUMO

Forage and turf grasses are continually cut and grazed by livestock, however very little is known concerning the perception or molecular responses to wounding. Mechanical wounding rapidly activated a 46 kDa and a 44 kDa mitogen-activated protein kinase (MAPK) in six different grass species. In the model grass species Lolium temulentum, the 46 kDa MAPK was rapidly activated within 5 min of wounding both locally and systemically in an adjacent unwounded tiller. This indicates that wounding generates a rapidly propagated long-distance signal that activates a MAPK in the distal portions of the plant. This 46 kDa MAPK activity was not enhanced by the addition of the pathogen-associated signal salicylic acid (SA) to the wound site nor induced when exposed to methyl jasmonate (MJ), which is a potent inducer of the wound response in dicotyledonous plants. However, pretreatment with MJ increased the wound-induced activity of the 44 kDa MAPK over the activity in control plants.


Assuntos
Sistema de Sinalização das MAP Quinases , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Poaceae/metabolismo , Acetatos/metabolismo , Catalase/metabolismo , Ciclopentanos/metabolismo , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Proteínas Quinases Ativadas por Mitógeno/genética , Oxilipinas/metabolismo , Folhas de Planta/fisiologia , Proteínas de Plantas/metabolismo , Poaceae/enzimologia , Poaceae/genética , Ácido Salicílico/metabolismo
19.
Plant Signal Behav ; 5(1): 42-4, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20592806

RESUMO

Systemin is a wound signaling peptide from tomato that is important for plant defenses against herbivory. The systemin receptor was initially identified as the tomato homolog of the brassinosteroid receptor BRI1, but genetic evidence argued against this finding. However, we found that BRI1 may function as an inappropriate systemin binding protein that does not activate the systemin signaling pathway. Here we provide evidence that systemin perception is localized in a tissue-type specific manner. Mesophyll protoplasts were not sensitive to systemin, while they responded to other elicitors. We hypothesize that the elusive systemin receptor is a protein with high similarity to BRI1 which is specifically localized in vascular tissue like the systemin precursor prosystemin. Binding of systemin to BRI1 may be an artifact of transgenic BRI1-overexpressing plants, but does not take place in wild type tomato cells.


Assuntos
Peptídeos/metabolismo , Proteínas de Plantas/metabolismo , Receptores de Superfície Celular/metabolismo , Solanum lycopersicum/metabolismo , Imunidade Inata , Doenças das Plantas , Ligação Proteica , Protoplastos/metabolismo , Transdução de Sinais
20.
Phytochemistry ; 71(17-18): 2024-37, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-20970815

RESUMO

Transgenic tomato (Solanum lycopersicum) plants that overexpress the Prosystemin gene (35S::PS) and plants with a mutation in the JA biosynthetic pathway (def1) are known to exhibit a constitutive or reduced wound response, respectively. Here it is demonstrated that several independent 35S::PS lines emit high levels of specific volatiles in addition to increased accumulation of proteinase inhibitors (PIs). Furthermore, the temporal dynamics of systemically induced volatile compounds including green-leaf volatiles, terpenes, and shikimic acid-derivatives from 35S::PS and def1 plants in response to herbivore wounding and treatment with jasmonic acid (JA) are described. Application of JA induced defense protein accumulation and volatile emissions in wild type plants, but did not further increase systemic volatile emissions from 35S::PS plants. Wounding by Manduca sexta larvae induced synthesis of defense proteins and emission of volatiles in wild type plants, but not in def1 plants. Application of jasmonic acid restored the local and systemic accumulation of defense proteins in def1, as well as enhanced herbivore-induced volatile emissions. These results provide strong support for the role of prosystemin- and JA-signaling in the regulation of volatile emissions in tomato plants.


Assuntos
Ciclopentanos/metabolismo , Manduca/fisiologia , Oxilipinas/metabolismo , Peptídeos/fisiologia , Solanum lycopersicum/fisiologia , Compostos Orgânicos Voláteis/metabolismo , Animais , Sequência de Bases , Ciclopentanos/análise , Regulação da Expressão Gênica de Plantas , Larva/genética , Larva/fisiologia , Solanum lycopersicum/genética , Solanum lycopersicum/metabolismo , Manduca/embriologia , Estrutura Molecular , Oxilipinas/análise , Peptídeos/análise
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