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1.
Front Microbiol ; 12: 686998, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34220778

RESUMO

Plant-beneficial microbes have drawn wide attention due to their potential application as bio-control agents and bio-fertilizers. Moso bamboo, which is among the monocots with the highest growth rate, lives perennially with abundant microbes that may benefit annually growing crops. Genome information of moso bamboo associated bacteria remains underexplored. We isolated and identified a novel Paraburkholderia strain Suichang626 from moso bamboo roots. Growth promoting effects of Suichang626 on both moso bamboo and seedlings of the model dicot Arabidopsis thaliana were documented in laboratory conditions. To gain insight into the genetic basis of this growth promotion effect, we sequenced the genome of Suichang626. Evidenced by genome-wide phylogeny data, we propose that Suichang626 is a novel strain of Paraburkholderia sacchari. Gene homologs encoding biosynthesis of the plant growth-promoting chemicals, acetoin and 2,3-butanediol, were identified in the genome of Suichang626. Comparative genomics was further performed with plant-beneficial and plant/animal pathogenic species of Paraburkholderia and Burkholderia. Genes related to volatile organic compounds, nitrogen fixation, and auxin biosynthesis were discovered specifically in the plant growth-promoting species of both genera.

2.
IMA Fungus ; 12(1): 8, 2021 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-33741074

RESUMO

Protomyces is an understudied genus of yeast-like fungi currently defined as phytopathogens of only Umbelliferae and Compositae. Species relationships and boundaries remain controversial and molecular data are lacking. Of the 82 named Protomyces, we found few recent studies and six available cultures. We previously isolated Protomyces strains from wild Arabidopsis thaliana, a member of Brassicaceae, a family distant from accepted Protomyces hosts. We previously sequenced the genomes of all available Protomyces species, and P. arabidopsidicola sp. nov. strain C29, from Arabidopsis. Phylogenomics suggests this new species occupied a unique position in the genus. Genomic, morphological, and physiological characteristics distinguished P. arabidopsidicola sp. nov. from other Protomyces. Nuclear gene phylogenetic marker analysis suggests actin1 gene DNA sequences could be used with nuclear ribosomal DNA internal transcribed spacer sequences for rapid identification of Protomyces species. Previous studies demonstrated P. arabidopsidicola sp. nov. could persist on the Arabidopsis phyllosphere and Protomyces sequences were discovered on Arabidopsis at multiple sites in different countries. We conclude that the strain C29 represents a novel Protomyces species and propose the name of P. arabidopsidicola sp. nov. Consequently, we propose that Protomyces is not strictly associated only with the previously recognized host plants.

3.
Plants (Basel) ; 10(1)2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33467413

RESUMO

Image-based symptom scoring of plant diseases is a powerful tool for associating disease resistance with plant genotypes. Advancements in technology have enabled new imaging and image processing strategies for statistical analysis of time-course experiments. There are several tools available for analyzing symptoms on leaves and fruits of crop plants, but only a few are available for the model plant Arabidopsis thaliana (Arabidopsis). Arabidopsis and the model fungus Botrytis cinerea (Botrytis) comprise a potent model pathosystem for the identification of signaling pathways conferring immunity against this broad host-range necrotrophic fungus. Here, we present two strategies to assess severity and symptom progression of Botrytis infection over time in Arabidopsis leaves. Thus, a pixel classification strategy using color hue values from red-green-blue (RGB) images and a random forest algorithm was used to establish necrotic, chlorotic, and healthy leaf areas. Secondly, using chlorophyll fluorescence (ChlFl) imaging, the maximum quantum yield of photosystem II (Fv/Fm) was determined to define diseased areas and their proportion per total leaf area. Both RGB and ChlFl imaging strategies were employed to track disease progression over time. This has provided a robust and sensitive method for detecting sensitive or resistant genetic backgrounds. A full methodological workflow, from plant culture to data analysis, is described.

4.
Plant Cell Environ ; 44(2): 548-558, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33131061

RESUMO

In Arabidopsis, two leaf-type ferredoxin-NADP+ oxidoreductase (LFNR) isoforms function in photosynthetic electron flow in reduction of NADP+ , while two root-type FNR (RFNR) isoforms catalyse reduction of ferredoxin in non-photosynthetic plastids. As the key to understanding, the function of RFNRs might lie in their spatial and temporal distribution in different plant tissues and cell types, we examined expression of RFNR1 and RFNR2 genes using ß-glucuronidase (GUS) reporter lines and investigated accumulation of distinct RFNR isoforms using a GFP approach and Western blotting upon various stresses. We show that while RFNR1 promoter is active in leaf veins, root tips and in the stele of roots, RFNR2 promoter activity is present in leaf tips and root stele, epidermis and cortex. RFNR1 protein accumulates as a soluble protein within the plastids of root stele cells, while RFNR2 is mainly present in the outer root layers. Ozone treatment of plants enhanced accumulation of RFNR1, whereas low temperature treatment specifically affected RFNR2 accumulation in roots. We further discuss the physiological roles of RFNR1 and RFNR2 based on characterization of rfnr1 and rfnr2 knock-out plants and show that although the function of these proteins is partly redundant, the RFNR proteins are essential for plant development and survival.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/enzimologia , Ferredoxina-NADP Redutase/metabolismo , Oxirredutases/genética , Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Temperatura Baixa , Transporte de Elétrons , Ferredoxina-NADP Redutase/genética , Oxirredutases/metabolismo , Fotossíntese , Folhas de Planta/enzimologia , Folhas de Planta/genética , Raízes de Plantas/enzimologia , Raízes de Plantas/genética , Plastídeos/enzimologia , Isoformas de Proteínas , Estresse Fisiológico
5.
Mol Plant Microbe Interact ; 34(1): 75-87, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33006531

RESUMO

Plants require interaction between signaling pathways to differentiate and integrate stress responses and deploy appropriate defenses. The hormones ethylene, salicylic acid (SA), and jasmonic acid (JA) are important regulators of plant defenses. Numerous interactions between these signaling pathways are the cornerstone of robust plant immunity. Additionally, during the early response to pathogens, reactive oxygen species (ROS) act as signaling molecules. Here, we examined the extent of signal interaction in the early stages of Botrytis cinerea infection. To enable a comparison between B. cinerea infection with ROS signaling, we subjected plants to ozone treatment, which stimulates an apoplastic ROS burst. We used a collection of single, double, and triple signaling mutants defective in hormone signaling and biosynthesis and subjected them to B. cinerea infection and ozone treatment at different timepoints. We examined lesion size, cell death, and gene expression (both quantitatively and spatially). The two treatments shared many similarities, especially in JA-insensitive mutants, which were sensitive to both treatments. Unexpectedly, a B. cinerea-susceptible JA-insensitive mutant (coi1), became tolerant when both SA biosynthesis and signaling was impaired (coi1 npr1 sid2), demonstrating that JA responses may be under the control of SA. Extensive marker gene analysis indicated JA as the main regulator of both B. cinerea and ozone defenses. In addition, we identified the transcription factor SR1 as a crucial regulator of PLANT DEFENSIN expression and cell-death regulation, which contributes to resistance to B. cinerea. Overall, our work further defines the context of ROS in plant defense signaling.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.


Assuntos
Arabidopsis , Botrytis , Morte Celular , Doenças das Plantas , Reguladores de Crescimento de Plantas , Transdução de Sinais , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Botrytis/fisiologia , Doenças das Plantas/microbiologia , Reguladores de Crescimento de Plantas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Estresse Fisiológico/genética
6.
Plant Physiol ; 182(2): 1161-1181, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31659127

RESUMO

Plants optimize their growth and survival through highly integrated regulatory networks that coordinate defensive measures and developmental transitions in response to environmental cues. Protein phosphatase 2A (PP2A) is a key signaling component that controls stress reactions and growth at different stages of plant development, and the PP2A regulatory subunit PP2A-B'γ is required for negative regulation of pathogenesis responses and for maintenance of cell homeostasis in short-day conditions. Here, we report molecular mechanisms by which PP2A-B'γ regulates Botrytis cinerea resistance and leaf senescence in Arabidopsis (Arabidopsis thaliana). We extend the molecular functionality of PP2A-B'γ to a protein kinase-phosphatase interaction with the defense-associated calcium-dependent protein kinase CPK1 and present indications this interaction may function to control CPK1 activity. In presenescent leaf tissues, PP2A-B'γ is also required to negatively control the expression of salicylic acid-related defense genes, which have recently proven vital in plant resistance to necrotrophic fungal pathogens. In addition, we find the premature leaf yellowing of pp2a-b'γ depends on salicylic acid biosynthesis via SALICYLIC ACID INDUCTION DEFICIENT2 and bears the hallmarks of developmental leaf senescence. We propose PP2A-B'γ age-dependently controls salicylic acid-related signaling in plant immunity and developmental leaf senescence.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/enzimologia , Botrytis/imunologia , Senescência Celular/genética , Resistência à Doença/genética , Doenças das Plantas/imunologia , Folhas de Planta/metabolismo , Proteína Fosfatase 2/metabolismo , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/microbiologia , Proteínas de Arabidopsis/genética , Cálcio/metabolismo , Senescência Celular/fisiologia , Cisteína Endopeptidases/genética , Cisteína Endopeptidases/metabolismo , Resistência à Doença/imunologia , Regulação da Expressão Gênica no Desenvolvimento/genética , Regulação da Expressão Gênica de Plantas/genética , Genótipo , Transferases Intramoleculares/genética , Transferases Intramoleculares/metabolismo , Mutação , Fenótipo , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Imunidade Vegetal/genética , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Ligação Proteica , Proteínas Quinases/genética , Proteínas Quinases/metabolismo , Proteína Fosfatase 2/genética , Ácido Salicílico/metabolismo , Transdução de Sinais/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Transcriptoma/genética
7.
J Exp Bot ; 70(20): 5971-5984, 2019 10 24.
Artigo em Inglês | MEDLINE | ID: mdl-31328223

RESUMO

Prevailing evidence indicates that abscisic acid (ABA) negatively influences immunity to the fungal pathogen Botrytis cinerea in most but not all cases. ABA is required for cuticle biosynthesis, and cuticle permeability enhances immunity to Botrytis via unknown mechanisms. This complex web of responses obscures the role of ABA in Botrytis immunity. Here, we addressed the relationships between ABA sensitivity, cuticle permeability, and Botrytis immunity in the Arabidopsis thaliana ABA-hypersensitive mutants protein phosphatase2c quadruple mutant (pp2c-q) and enhanced response to aba1 (era1-2). Neither pp2c-q nor era1-2 exhibited phenotypes predicted by the known roles of ABA; conversely, era1-2 had a permeable cuticle and was Botrytis resistant. We employed RNA-seq analysis in cuticle-permeable mutants of differing ABA sensitivities and identified a core set of constitutively activated genes involved in Botrytis immunity and susceptibility to biotrophs, independent of ABA signaling. Furthermore, botrytis susceptible1 (bos1), a mutant with deregulated cell death and enhanced ABA sensitivity, suppressed the Botrytis immunity of cuticle permeable mutants, and this effect was linearly correlated with the extent of spread of wound-induced cell death in bos1. Overall, our data demonstrate that Botrytis immunity conferred by cuticle permeability can be genetically uncoupled from PP2C-regulated ABA sensitivity, but requires negative regulation of a parallel ABA-dependent cell-death pathway.


Assuntos
Ácido Abscísico/metabolismo , Arabidopsis/metabolismo , Arabidopsis/microbiologia , Botrytis/imunologia , Botrytis/patogenicidade , Arabidopsis/imunologia , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Regulação da Expressão Gênica de Plantas , Doenças das Plantas/microbiologia , Transdução de Sinais/fisiologia
8.
Free Radic Biol Med ; 134: 555-566, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30738155

RESUMO

Reactive oxygen species (ROS) are key signalling intermediates in plant metabolism, defence, and stress adaptation. In plants, both the chloroplast and mitochondria are centres of metabolic control and ROS production, which coordinate stress responses in other cell compartments. The herbicide and experimental tool, methyl viologen (MV) induces ROS generation in the chloroplast under illumination, but is also toxic in non-photosynthetic organisms. We used MV to probe plant ROS signalling in compartments other than the chloroplast. Taking a genetic approach in the model plant Arabidopsis (Arabidopsis thaliana), we used natural variation, QTL mapping, and mutant studies with MV in the light, but also under dark conditions, when the chloroplast electron transport is inactive. These studies revealed a light-independent MV-induced ROS-signalling pathway, suggesting mitochondrial involvement. Mitochondrial Mn SUPEROXIDE DISMUTASE was required for ROS-tolerance and the effect of MV was enhanced by exogenous sugar, providing further evidence for the role of mitochondria. Mutant and hormone feeding assays revealed roles for stress hormones in organellar ROS-responses. The radical-induced cell death1 mutant, which is tolerant to MV-induced ROS and exhibits altered mitochondrial signalling, was used to probe interactions between organelles. Our studies suggest that mitochondria are involved in the response to ROS induced by MV in plants.


Assuntos
Arabidopsis/metabolismo , Cloroplastos/metabolismo , Mitocôndrias/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Paraquat/farmacologia , Arabidopsis/efeitos dos fármacos , Cloroplastos/efeitos dos fármacos , Transporte de Elétrons , Herbicidas/farmacologia , Mitocôndrias/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais
9.
Plant Cell ; 30(11): 2813-2837, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30361234

RESUMO

Guard cells control the aperture of stomatal pores to balance photosynthetic carbon dioxide uptake with evaporative water loss. Stomatal closure is triggered by several stimuli that initiate complex signaling networks to govern the activity of ion channels. Activation of SLOW ANION CHANNEL1 (SLAC1) is central to the process of stomatal closure and requires the leucine-rich repeat receptor-like kinase (LRR-RLK) GUARD CELL HYDROGEN PEROXIDE-RESISTANT1 (GHR1), among other signaling components. Here, based on functional analysis of nine Arabidopsis thaliana ghr1 mutant alleles identified in two independent forward-genetic ozone-sensitivity screens, we found that GHR1 is required for stomatal responses to apoplastic reactive oxygen species, abscisic acid, high CO2 concentrations, and diurnal light/dark transitions. Furthermore, we show that the amino acid residues of GHR1 involved in ATP binding are not required for stomatal closure in Arabidopsis or the activation of SLAC1 anion currents in Xenopus laevis oocytes and present supporting in silico and in vitro evidence suggesting that GHR1 is an inactive pseudokinase. Biochemical analyses suggested that GHR1-mediated activation of SLAC1 occurs via interacting proteins and that CALCIUM-DEPENDENT PROTEIN KINASE3 interacts with GHR1. We propose that GHR1 acts in stomatal closure as a scaffolding component.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Estômatos de Plantas/metabolismo , Estômatos de Plantas/fisiologia , Proteínas Quinases/metabolismo , Proteínas de Arabidopsis/genética , Dióxido de Carbono/metabolismo , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Fosforilação/genética , Fosforilação/fisiologia , Ligação Proteica , Transdução de Sinais/genética , Transdução de Sinais/fisiologia
10.
Plant Cell Environ ; 41(4): 782-796, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29333607

RESUMO

The atmospheric pollutant ozone (O3 ) is a strong oxidant that causes extracellular reactive oxygen species (ROS) formation, has significant ecological relevance, and is used here as a non-invasive ROS inducer to study plant signalling. Previous genetic screens identified several mutants exhibiting enhanced O3 sensitivity, but few with enhanced tolerance. We found that loss-of-function mutants in Arabidopsis MLO2, a gene implicated in susceptibility to powdery mildew disease, exhibit enhanced dose-dependent tolerance to O3 and extracellular ROS, but a normal response to intracellular ROS. This phenotype is increased in a mlo2 mlo6 mlo12 triple mutant, reminiscent of the genetic redundancy of MLO genes in powdery mildew resistance. Stomatal assays revealed that enhanced O3 tolerance in mlo2 mutants is not caused by altered stomatal conductance. We explored modulation of the mlo2-associated O3 tolerance, powdery mildew resistance, and early senescence phenotypes by genetic epistasis analysis, involving mutants with known effects on ROS sensitivity or antifungal defence. Mining of publicly accessible microarray data suggests that these MLO proteins regulate accumulation of abiotic stress response transcripts, and transcript accumulation of MLO2 itself is O3 responsive. In summary, our data reveal MLO2 as a novel negative regulator in plant ROS responses, which links biotic and abiotic stress response pathways.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Proteínas de Membrana/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Regulação da Expressão Gênica de Plantas , Glucanos/metabolismo , Doenças das Plantas/microbiologia , Estômatos de Plantas/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Estresse Fisiológico
11.
Physiol Plant ; 162(2): 191-204, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28857168

RESUMO

Plants live in a world where they are challenged by abiotic and biotic stresses. In response to unfavorable conditions or an acute challenge like a pathogen attack, plants use various signaling pathways that regulate expression of defense genes and other mechanisms to provide resistance or stress adaptation. Identification of the regulatory steps in defense signaling has seen much progress in recent years. Many of the identified signaling pathways show interactions with each other, exemplified by the modulation of the jasmonic acid response by salicylic acid. Accordingly, defense regulation is more appropriately thought of as a web of interactions, rather than linear pathways. Here we describe various regulatory components and how they interact to provide an appropriate defense response. One of the common assays to monitor the output of defense signaling, as well as interaction between signaling pathways, is the measurement of altered gene expression. We illustrate that, while this is a suitable assay to monitor defense regulation, it can also inadvertently provide overstated conclusions about interaction among signaling pathways.


Assuntos
Reguladores de Crescimento de Plantas/metabolismo , Plantas/metabolismo , Transdução de Sinais , Estresse Fisiológico , Ácido Abscísico/metabolismo , Ciclopentanos/metabolismo , Secas , Regulação da Expressão Gênica de Plantas , Modelos Biológicos , Oxilipinas/metabolismo , Doenças das Plantas/genética , Plantas/genética , Ácido Salicílico/metabolismo
12.
Plant J ; 89(1): 112-127, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27598402

RESUMO

Glucosinolates (GSL) of cruciferous plants comprise a major group of structurally diverse secondary compounds which act as deterrents against aphids and microbial pathogens and have large commercial and ecological impacts. While the transcriptional regulation governing the biosynthesis and modification of GSL is now relatively well understood, post-translational regulatory components that specifically determine the structural variation of indole glucosinolates have not been reported. We show that the cytoplasmic protein phosphatase 2A regulatory subunit B'γ (PP2A-B'γ) physically interacts with indole glucosinolate methyltransferases and controls the methoxylation of indole glucosinolates and the formation of 4-methoxy-indol-3-yl-methyl glucosinolate in Arabidopsis leaves. By taking advantage of proteomic approaches and metabolic analysis we further demonstrate that PP2A-B'γ is required to control the abundance of oligomeric protein complexes functionally linked with the activated methyl cycle and the trans-methylation capacity of leaf cells. These findings highlight the key regulatory role of PP2A-B'γ in methionine metabolism and provide a previously unrecognized perspective for metabolic engineering of glucosinolate metabolism in cruciferous plants.


Assuntos
Proteínas de Arabidopsis/metabolismo , Glucosinolatos/metabolismo , Folhas de Planta/metabolismo , Proteína Fosfatase 2/metabolismo , Sequência de Aminoácidos , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Metionina/metabolismo , Metilação , Metiltransferases/genética , Metiltransferases/metabolismo , Modelos Biológicos , Folhas de Planta/genética , Ligação Proteica , Proteína Fosfatase 2/genética , Subunidades Proteicas/genética , Subunidades Proteicas/metabolismo , Proteômica/métodos , Homologia de Sequência de Aminoácidos
13.
Sci Rep ; 6: 39403, 2016 12 22.
Artigo em Inglês | MEDLINE | ID: mdl-28004784

RESUMO

The genetic model plant Arabidopsis thaliana (arabidopsis) has been instrumental to recent advances in our understanding of the molecular function of the plant immune system. However, this work has not yet included plant associated and phytopathogenic yeasts largely due to a lack of yeast species known to interact with arabidopsis. The plant phylloplane is a significant habitat for neutral-residents, plant-growth and health-promoting species, and latent-pathogenic species. However, yeast phylloplane residents of arabidopsis remain underexplored. To address this, resident yeasts from the phyllosphere of wild arabidopsis collected in field conditions have been isolated and characterized. A total of 95 yeast strains representing 23 species in 9 genera were discovered, including potentially psychrophilic and pathogenic strains. Physiological characterization revealed thermotolerance profiles, sensitivity to the arabidopsis phytoalexin camalexin, the production of indolic compounds, and the ability to activate auxin responses in planta. These results indicate a rich diversity of yeasts present in the arabidopsis phylloplane and have created culture resources and information useful in the development of model systems for arabidopsis-yeast interactions.


Assuntos
Arabidopsis/microbiologia , Leveduras/isolamento & purificação , Arabidopsis/metabolismo , Ecossistema , Ácidos Indolacéticos/metabolismo , Folhas de Planta/microbiologia , Sesquiterpenos/metabolismo
14.
Plant Cell ; 28(10): 2493-2509, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27694184

RESUMO

Activation of the guard cell S-type anion channel SLAC1 is important for stomatal closure in response to diverse stimuli, including elevated CO2 The majority of known SLAC1 activation mechanisms depend on abscisic acid (ABA) signaling. Several lines of evidence point to a parallel ABA-independent mechanism of CO2-induced stomatal regulation; however, molecular details of this pathway remain scarce. Here, we isolated a dominant mutation in the protein kinase HIGH LEAF TEMPERATURE1 (HT1), an essential regulator of stomatal CO2 responses, in an ozone sensitivity screen of Arabidopsis thaliana The mutation caused constitutively open stomata and impaired stomatal CO2 responses. We show that the mitogen-activated protein kinases (MPKs) MPK4 and MPK12 can inhibit HT1 activity in vitro and this inhibition is decreased for the dominant allele of HT1. We also show that HT1 inhibits the activation of the SLAC1 anion channel by the protein kinases OPEN STOMATA1 and GUARD CELL HYDROGEN PEROXIDE-RESISTANT1 (GHR1) in Xenopus laevis oocytes. Notably, MPK12 can restore SLAC1 activation in the presence of HT1, but not in the presence of the dominant allele of HT1. Based on these data, we propose a model for sequential roles of MPK12, HT1, and GHR1 in the ABA-independent regulation of SLAC1 during CO2-induced stomatal closure.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Estômatos de Plantas/metabolismo , Proteínas Quinases/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Dióxido de Carbono/metabolismo , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Proteínas Quinases Ativadas por Mitógeno/genética , Mutação/genética , Estômatos de Plantas/genética , Proteínas Quinases/genética , Transdução de Sinais/genética , Transdução de Sinais/fisiologia
15.
Mol Plant ; 9(6): 926-38, 2016 06 06.
Artigo em Inglês | MEDLINE | ID: mdl-27060495

RESUMO

The cuticle is the outer physical barrier of aerial plant surfaces and an important interaction point between plants and the environment. Many environmental stresses affect cuticle formation, yet the regulatory pathways involved remain undefined. We used a genetics and gene expression analysis in Arabidopsis thaliana to define an abscisic acid (ABA) signaling loop that positively regulates cuticle formation via the core ABA signaling pathway, including the PYR/PYL receptors, PP2C phosphatase, and SNF1-Related Protein Kinase (SnRK) 2.2/SnRK2.3/SnRK2.6. Downstream of the SnRK2 kinases, cuticle formation was not regulated by the ABA-responsive element-binding transcription factors but rather by DEWAX, MYB16, MYB94, and MYB96. Additionally, low air humidity increased cuticle formation independent of the core ABA pathway and cell death/reactive oxygen species signaling attenuated expression of cuticle-biosynthesis genes. In Physcomitrella patens, exogenous ABA suppressed expression of cuticle-related genes, whose Arabidopsis orthologs were ABA-induced. Hence, the mechanisms regulating cuticle formation are conserved but sophisticated in land plants. Signaling specifically related to cuticle deficiency was identified to play a major role in the adaptation of ABA signaling pathway mutants to increased humidity and in modulating their immunity to Botrytis cinerea in Arabidopsis. These results define a cuticle-specific downstream branch in the ABA signaling pathway that regulates responses to the external environment.


Assuntos
Ácido Abscísico/metabolismo , Arabidopsis/metabolismo , Arabidopsis/microbiologia , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Bryopsida/metabolismo , Bryopsida/fisiologia , Regulação da Expressão Gênica de Plantas
16.
New Phytol ; 208(3): 647-55, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26174112

RESUMO

With the tremendous progress of the past decades, molecular plant science is becoming more unified than ever. We now have the exciting opportunity to further connect subdisciplines and understand plants as whole organisms, as will be required to efficiently utilize them in natural and agricultural systems to meet human needs. The subfields of photosynthesis, plant developmental biology and plant stress are used as examples to discuss how plant science can become better integrated. The challenges, strategies and rich opportunities for the integration of the plant sciences are discussed. In recent years, more and more overlap between various subdisciplines has been inadvertently discovered including tradeoffs that may occur in plants engineered for biotechnological applications. Already important, bioinformatics and computational modelling will become even more central to structuring and understanding the ever growing amounts of data. The process of integrating and overlapping fields in plant biology research is advancing, but plant science will benefit from dedicating more effort and urgency to reach across its boundaries.


Assuntos
Botânica/tendências , Fotossíntese , Desenvolvimento Vegetal , Plantas/metabolismo , Estresse Fisiológico , Comunicação Celular , Parede Celular/metabolismo , Cloroplastos/metabolismo , Biologia Computacional , Expressão Gênica , Imunidade Vegetal , Madeira/metabolismo
17.
Anal Biochem ; 477: 38-40, 2015 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-25513723

RESUMO

The standard digestion-ligation cloning method enables synthesis of large amounts of complementary DNA (cDNA) from a model organism facilitating study of the transcriptome. Here, we used cDNA amplification of the dimorphic yeast Taphrina betulina as an example of how a library construction protocol can significantly increase sequencing throughput. Two modification steps were introduced to the Evrogen standard Mint-2 protocol to improve its suitability for next-generation sequencing projects. We performed two partial Illumina MiSeq sequencing runs with the modified protocol: one with and one without biotin-purified primers. The results demonstrated that biotinylated libraries increased both accuracy and throughput of the modified protocol. Moreover, our sequencing results indicate that a sequence-specific miscall may affect the output of Illumina's MiSeq platform.


Assuntos
Ascomicetos/genética , Perfilação da Expressão Gênica/métodos , DNA Polimerase Dirigida por RNA/metabolismo , Análise de Sequência/métodos , Clonagem Molecular , Biblioteca Gênica
18.
PLoS Genet ; 10(2): e1004112, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24550736

RESUMO

Plant responses to changes in environmental conditions are mediated by a network of signaling events leading to downstream responses, including changes in gene expression and activation of cell death programs. Arabidopsis thaliana RADICAL-INDUCED CELL DEATH1 (RCD1) has been proposed to regulate plant stress responses by protein-protein interactions with transcription factors. Furthermore, the rcd1 mutant has defective control of cell death in response to apoplastic reactive oxygen species (ROS). Combining transcriptomic and functional genomics approaches we first used microarray analysis in a time series to study changes in gene expression after apoplastic ROS treatment in rcd1. To identify a core set of cell death regulated genes, RCD1-regulated genes were clustered together with other array experiments from plants undergoing cell death or treated with various pathogens, plant hormones or other chemicals. Subsequently, selected rcd1 double mutants were constructed to further define the genetic requirements for the execution of apoplastic ROS induced cell death. Through the genetic analysis we identified WRKY70 and SGT1b as cell death regulators functioning downstream of RCD1 and show that quantitative rather than qualitative differences in gene expression related to cell death appeared to better explain the outcome. Allocation of plant energy to defenses diverts resources from growth. Recently, a plant response termed stress-induced morphogenic response (SIMR) was proposed to regulate the balance between defense and growth. Using a rcd1 double mutant collection we show that SIMR is mostly independent of the classical plant defense signaling pathways and that the redox balance is involved in development of SIMR.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Morte Celular/genética , Proteínas Nucleares/genética , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/genética , Proteínas de Arabidopsis/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Genoma de Planta , Genômica , Proteínas Nucleares/metabolismo , Estresse Fisiológico/genética
19.
New Phytol ; 200(3): 634-640, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23952703

RESUMO

Wounding results in the controlled cell death of a few rows of cells adjacent to disrupted cells resulting in physical wound closure, which combined with phenolic compound deposition, prevents water loss and pathogen entry. The control of these processes remains uncharacterized. Cell death in a mutant of Arabidopsis thaliana lacking BOTRYTIS SENSITIVE1/MYB108 (BOS1/MYB108) function was characterized utilizing physiological, cell biological and genetic methods. The bos1 mutant has a wound induced runaway cell death that includes enhanced reactive oxygen species (ROS) production that followed the extent of enhanced cell death. Exogenous abscisic acid (ABA) enhanced wound induced cell death in Col-0 plants and was sufficient to trigger cell death in bos1. Uncontrolled cell death was dependent of the production and perception of ABA. Furthermore, bos1 had altered sensitivity to and accumulation of ABA. Arabidopsis possesses a genetic program controlling the extent of wound inducible cell death. BOS1 acts as a negative regulator of ABA induced cell death, which functions in the control of this wound sealing program. This program is distinct from other known cell death programs in that it is ABA dependent, but independent of salicylate biosynthesis, ethylene, jasmonate, metacaspases and ROS derived from RBOHD and RBOHF.


Assuntos
Ácido Abscísico/genética , Proteínas de Arabidopsis/genética , Arabidopsis/genética , Morte Celular/genética , Resistência à Doença/genética , Regulação da Expressão Gênica de Plantas , Doenças das Plantas/genética , Fatores de Transcrição/genética , Ácido Abscísico/metabolismo , Ácido Abscísico/farmacologia , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Mutação , Reguladores de Crescimento de Plantas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Fatores de Transcrição/metabolismo
20.
New Phytol ; 200(2): 498-510, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23834670

RESUMO

Cell death of xylem elements is manifested by rupture of the tonoplast and subsequent autolysis of the cellular contents. Metacaspases have been implicated in various forms of plant cell death but regulation and execution of xylem cell death by metacaspases remains unknown. Analysis of the type II metacaspase gene family in Arabidopsis thaliana supported the function of METACASPASE 9 (AtMC9) in xylem cell death. Progression of xylem cell death was analysed in protoxylem vessel elements of 3-d-old atmc9 mutant roots using reporter gene analysis and electron microscopy. Protoxylem cell death was normally initiated in atmc9 mutant lines, but detailed electron microscopic analyses revealed a role for AtMC9 in clearance of the cell contents post mortem, that is after tonoplast rupture. Subcellular localization of fluorescent AtMC9 reporter fusions supported a post mortem role for AtMC9. Further, probe-based activity profiling suggested a function of AtMC9 on activities of papain-like cysteine proteases. Our data demonstrate that the function of AtMC9 in xylem cell death is to degrade vessel cell contents after vacuolar rupture. We further provide evidence on a proteolytic cascade in post mortem autolysis of xylem vessel elements and suggest that AtMC9 is part of this cascade.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Caspases/metabolismo , Regulação da Expressão Gênica de Plantas , Xilema/metabolismo , Arabidopsis/genética , Arabidopsis/ultraestrutura , Proteínas de Arabidopsis/genética , Caspases/genética , Morte Celular , Perfilação da Expressão Gênica , Análise de Sequência com Séries de Oligonucleotídeos , Doenças das Plantas/microbiologia , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Plantas Geneticamente Modificadas , Proteólise , Pseudomonas syringae/patogenicidade , Proteínas Recombinantes de Fusão , Vacúolos/metabolismo , Xilema/genética , Xilema/ultraestrutura
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