WorldWideScience

Sample records for plant arabidopsis thaliana

  1. Metabolic changes in Arabidopsis thaliana plants overexpressing chalcone synthase

    NARCIS (Netherlands)

    Dao, Thi Thanh Hien

    2010-01-01

    The study has shown that it is possible to introduce the heterologous CHS gene in Arabidopsis thaliana and common multicopies of transgenes containing plants were obtained. Analysis of the change in metabolome of CHS transgenic plants, high expression transgenic lines can be identified by markers su

  2. Diuretics prime plant immunity in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Yoshiteru Noutoshi

    Full Text Available Plant activators are agrochemicals that activate the plant immune system, thereby enhancing disease resistance. Due to their prophylactic and durable effects on a wide spectrum of diseases, plant activators can provide synergistic crop protection when used in combination with traditional pest controls. Although plant activators have achieved great success in wet-rice farming practices in Asia, their use is still limited. To isolate novel plant activators applicable to other crops, we screened a chemical library using a method that can selectively identify immune-priming compounds. Here, we report the isolation and characterization of three diuretics, bumetanide, bendroflumethiazide and clopamide, as immune-priming compounds. These drugs upregulate the immunity-related cell death of Arabidopsis suspension-cultured cells induced with an avirulent strain of Pseudomonas syringae pv. tomato in a concentration-dependent manner. The application of these compounds to Arabidopsis plants confers disease resistance to not only the avirulent but also a virulent strain of the pathogen. Unlike salicylic acid, an endogenous phytohormone that governs disease resistance in response to biotrophic pathogens, the three diuretic compounds analyzed here do not induce PR1 or inhibit plant growth, showing potential as lead compounds in a practical application.

  3. Diuretics Prime Plant Immunity in Arabidopsis thaliana

    Science.gov (United States)

    Noutoshi, Yoshiteru; Ikeda, Mika; Shirasu, Ken

    2012-01-01

    Plant activators are agrochemicals that activate the plant immune system, thereby enhancing disease resistance. Due to their prophylactic and durable effects on a wide spectrum of diseases, plant activators can provide synergistic crop protection when used in combination with traditional pest controls. Although plant activators have achieved great success in wet-rice farming practices in Asia, their use is still limited. To isolate novel plant activators applicable to other crops, we screened a chemical library using a method that can selectively identify immune-priming compounds. Here, we report the isolation and characterization of three diuretics, bumetanide, bendroflumethiazide and clopamide, as immune-priming compounds. These drugs upregulate the immunity-related cell death of Arabidopsis suspension-cultured cells induced with an avirulent strain of Pseudomonas syringae pv. tomato in a concentration-dependent manner. The application of these compounds to Arabidopsis plants confers disease resistance to not only the avirulent but also a virulent strain of the pathogen. Unlike salicylic acid, an endogenous phytohormone that governs disease resistance in response to biotrophic pathogens, the three diuretic compounds analyzed here do not induce PR1 or inhibit plant growth, showing potential as lead compounds in a practical application. PMID:23144763

  4. Arabidopsis thaliana: uma pequena planta um grande papel Arabidopsis thaliana: a small plant a big role

    Directory of Open Access Journals (Sweden)

    Carla Andréa Delatorre

    2008-12-01

    Full Text Available Arabidopsis thaliana é uma das espécies mais utilizadas na pesquisa científica atualmente. Apesar de não apresentar importância econômica direta, esta espécie é o foco de pesquisas na área da genética, bioquímica e fisiologia. O número de trabalhos publicados sobre a mesma aumentou significativamente após o seqüenciamento de seu genoma. Apesar do grande número de estudos existe ainda muita desinformação sobre qual o seu verdadeiro papel na pesquisa científica de espécies cultivadas e de que maneira o avanço no conhecimento adquirido com A. thaliana pode auxiliar o desenvolvimento de cultivares cada vez mais resistentes, adaptados e produtivos. Os objetivos deste trabalho são discutir as razões do uso da A. thaliana como espécie modelo e a aplicabilidade deste modelo no estudo de espécies cultivadas.Arabidopsis thaliana has been the species of choice for scientific research. Despite its lack of economic importance, it has been the focus of genetic, biochemical and physiological research worldwide. The number of published articles about arabidopsis has increased substantially after its genome was sequenced, and outgrew the number of articles related to economically important species. Despite the great number of studies involving arabidopsis, there is much disinformation about the actual role of this species in crop scientific research, as well as how the breakthroughs in arabidopsis research may help to develop more adapted and productive crops. This work aims to discuss reasons for using A. thaliana as a model species and the feasibility of this model for crop studies.

  5. Plant cell wall proteomics: the leadership of Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Cécile eALBENNE

    2013-05-01

    Full Text Available Plant cell wall proteins (CWPs progressively emerged as crucial components of cell walls although present in minor amounts. Cell wall polysaccharides such as pectins, hemicelluloses and cellulose represent more than 90% of primary cell wall mass, whereas hemicelluloses, cellulose and lignins are the main components of lignified secondary walls. All these polymers provide mechanical properties to cell walls, participate in cell shape and prevent water loss in aerial organs. However, cells walls need to be modified and customized during plant development and in response to environmental cues, thus contributing to plant adaptation. CWPs play essential roles in all these physiological processes and particularly in the dynamics of cell walls, which requires organization and rearrangements of polysaccharides as well as cell-to-cell communication. In the last ten years, plant cell wall proteomics has greatly contributed to a wider knowledge of CWPs. This update will deal with (i a survey of plant cell wall proteomics studies with a focus on Arabidopsis thaliana; (ii the main protein families identified and the still missing peptides; (iii the persistent issue of the non-canonical CWPs; (iv the present challenges to overcome technological bottlenecks; and (v the perspectives beyond cell wall proteomics to understand CWP functions.

  6. Plant cell wall proteomics: the leadership of Arabidopsis thaliana.

    Science.gov (United States)

    Albenne, Cécile; Canut, Hervé; Jamet, Elisabeth

    2013-01-01

    Plant cell wall proteins (CWPs) progressively emerged as crucial components of cell walls although present in minor amounts. Cell wall polysaccharides such as pectins, hemicelluloses, and cellulose represent more than 90% of primary cell wall mass, whereas hemicelluloses, cellulose, and lignins are the main components of lignified secondary walls. All these polymers provide mechanical properties to cell walls, participate in cell shape and prevent water loss in aerial organs. However, cell walls need to be modified and customized during plant development and in response to environmental cues, thus contributing to plant adaptation. CWPs play essential roles in all these physiological processes and particularly in the dynamics of cell walls, which requires organization and rearrangements of polysaccharides as well as cell-to-cell communication. In the last 10 years, plant cell wall proteomics has greatly contributed to a wider knowledge of CWPs. This update will deal with (i) a survey of plant cell wall proteomics studies with a focus on Arabidopsis thaliana; (ii) the main protein families identified and the still missing peptides; (iii) the persistent issue of the non-canonical CWPs; (iv) the present challenges to overcome technological bottlenecks; and (v) the perspectives beyond cell wall proteomics to understand CWP functions.

  7. Transcriptional responses of Arabidopsis thaliana plants to As (V stress

    Directory of Open Access Journals (Sweden)

    Yuan Joshua S

    2008-08-01

    Full Text Available Abstract Background Arsenic is toxic to plants and a common environmental pollutant. There is a strong chemical similarity between arsenate [As (V] and phosphate (Pi. Whole genome oligonucleotide microarrays were employed to investigate the transcriptional responses of Arabidopsis thaliana plants to As (V stress. Results Antioxidant-related genes (i.e. coding for superoxide dismutases and peroxidases play prominent roles in response to arsenate. The microarray experiment revealed induction of chloroplast Cu/Zn superoxide dismutase (SOD (at2g28190, Cu/Zn SOD (at1g08830, as well as an SOD copper chaperone (at1g12520. On the other hand, Fe SODs were strongly repressed in response to As (V stress. Non-parametric rank product statistics were used to detect differentially expressed genes. Arsenate stress resulted in the repression of numerous genes known to be induced by phosphate starvation. These observations were confirmed with qRT-PCR and SOD activity assays. Conclusion Microarray data suggest that As (V induces genes involved in response to oxidative stress and represses transcription of genes induced by phosphate starvation. This study implicates As (V as a phosphate mimic in the cell by repressing genes normally induced when available phosphate is scarce. Most importantly, these data reveal that arsenate stress affects the expression of several genes with little or unknown biological functions, thereby providing new putative gene targets for future research.

  8. Halomethane production in plants: Structure of the biosynthetic SAM-dependent halide methyltransferase from Arabidopsis thaliana**

    Science.gov (United States)

    Schmidberger, Jason W.; James, Agata B.; Edwards, Robert; Naismith, James H.; O’Hagan, David

    2012-01-01

    A product structure of the halomethane producing enzyme in plants (Arabidopsis thaliana) is reported and a model for presentation of chloride/bromide ion to the methyl group of S-adenosyl-L-methionine (SAM) is presented to rationalise nucleophilic halide attack for halomethane production, gaseous natural products that are produced globally. PMID:20376845

  9. Strictly NO3- Nutrition Alleviates Iron Deficiency Chlorosis in Arabidopsis thaliana Plants

    Directory of Open Access Journals (Sweden)

    Najoua Msilini

    2014-03-01

    Full Text Available The effects of NO3- nutrition on iron deficiency responses were investigated in Arabidopsis thaliana. Plants were grown with or without 5 µM Fe, and with NO3- alone or a mixture of NO3- and NH4+. The results indicated that, NO3- nutrition induced higher dry matter production, regardless the Fe concentration. Fe deficiency reduced growth activity, photosynthetic pigment concentration and Fe content of plants, whatever the N forms. This decrease was more pronounced in plants grown with mixed N source; those plants presented the highest EL and MDA and anthocyanin contents compared to plants grown under Fe sufficient conditions. In iron free-solutions, with NO3- as the sole nitrogen source, enhanced FC-R activity in the roots was observed. However, in the presence of NH4+, plants displayed some decrease in in FC-R and PEPC activities. The presence of NH4+ modified typical Fe stress responses in Arabidopsis thaliana plants.

  10. Analysis of the transgenerational iron deficiency stress memory in Arabidopsis thaliana plants

    OpenAIRE

    Murgia, Irene; Giacometti, Sonia; Balestrazzi, Alma; Paparella, Stefania; Pagliano, Cristina; Morandini, Piero

    2015-01-01

    We investigated the existence of the transgenerational memory of iron (Fe) deficiency stress, in Arabidopsis thaliana. Plants were grown under Fe deficiency/sufficiency, and so were their offspring. The frequency of somatic homologous recombination (SHR) events, of DNA strand breaks as well as the expression of the transcription elongation factor TFIIS-like gene increase when plants are grown under Fe deficiency. However, SHR frequency, DNA strand break events, and TFIIS-like gene expression ...

  11. Intertribal hybrid plants produced from crossing Arabidopsis thaliana with apomictic Boechera.

    Science.gov (United States)

    Lohe, Allan R; Perotti, Enrico

    2012-08-01

    Arabidopsis thaliana and Boechera belong to different tribes of the Brassicaceae and last shared a common ancestor 13-35 million years ago. A. thaliana reproduces sexually but some Boechera accessions reproduce by apomixis (asexual reproduction by seed). The two species are reproductively isolated, preventing introgression of the trait(s) controlling apomixis from Boechera into A. thaliana and their molecular characterisation. To identify if "escapers" from such hybridisation barriers exist, we crossed diploid or tetraploid A. thaliana mothers carrying a conditional male sterile mutation with a triploid Boechera apomict. These cross-pollinations generated zygotes and embryos. Most aborted or suffered multiple developmental defects at all stages of growth, but some seed matured and germinated. Seedlings grew slowly but eventually some developed into mature plants that were novel synthetic allopolyploid hybrids. With one exception, intertribal hybrids contained three Boechera plus either one or two A. thaliana genomes (depending on maternal ploidy) and were male and female sterile. The exception was a semi-fertile, sexual partial hybrid with one Boechera plus two A. thaliana genomes. The synthesis of "escapers" that survive rigorous early developmental challenges in crosses between A. thaliana and Boechera demonstrates that the inviability form of postzygotic reproductive isolation separating these distantly related species is not impenetrable. The recovery of a single semi-fertile partial hybrid also demonstrates that hybrid sterility, another form of postzygotic reproductive isolation, can be overcome between these species.

  12. Effect of plant growth regulators on leaf anatomy of the has mutant of Arabidopsis thaliana.

    Science.gov (United States)

    Janosević, D; Uzelac, B; Budimir, S

    2008-12-01

    In this study, the effect of plant growth regulators on leaf morphogenesis of the recessive T-DNA insertion mutant of Arabidopsis thaliana was analyzed. The morpho-anatomical analysis revealed that leaves of the has mutant are small and narrow, with lobed blades and disrupted tissue organization. When has plants were grown on the medium supplied with plant growth regulators: benzylaminopurine (BAP) or ethylene precursor, 1-aminocyclopropane-1-carboxylic acid (ACC), the leaf anatomy was partially restored to the wild type, although plants still exhibited morphological abnormalities.

  13. MIPS Arabidopsis thaliana Database (MAtDB): an integrated biological knowledge resource for plant genomics.

    Science.gov (United States)

    Schoof, Heiko; Ernst, Rebecca; Nazarov, Vladimir; Pfeifer, Lukas; Mewes, Hans-Werner; Mayer, Klaus F X

    2004-01-01

    Arabidopsis thaliana is the most widely studied model plant. Functional genomics is intensively underway in many laboratories worldwide. Beyond the basic annotation of the primary sequence data, the annotated genetic elements of Arabidopsis must be linked to diverse biological data and higher order information such as metabolic or regulatory pathways. The MIPS Arabidopsis thaliana database MAtDB aims to provide a comprehensive resource for Arabidopsis as a genome model that serves as a primary reference for research in plants and is suitable for transfer of knowledge to other plants, especially crops. The genome sequence as a common backbone serves as a scaffold for the integration of data, while, in a complementary effort, these data are enhanced through the application of state-of-the-art bioinformatics tools. This information is visualized on a genome-wide and a gene-by-gene basis with access both for web users and applications. This report updates the information given in a previous report and provides an outlook on further developments. The MAtDB web interface can be accessed at http://mips.gsf.de/proj/thal/db.

  14. Sequence and analysis of chromosome 4 of the plant Arabidopsis thaliana.

    Science.gov (United States)

    Mayer, K; Schüller, C; Wambutt, R; Murphy, G; Volckaert, G; Pohl, T; Düsterhöft, A; Stiekema, W; Entian, K D; Terryn, N; Harris, B; Ansorge, W; Brandt, P; Grivell, L; Rieger, M; Weichselgartner, M; de Simone, V; Obermaier, B; Mache, R; Müller, M; Kreis, M; Delseny, M; Puigdomenech, P; Watson, M; Schmidtheini, T; Reichert, B; Portatelle, D; Perez-Alonso, M; Boutry, M; Bancroft, I; Vos, P; Hoheisel, J; Zimmermann, W; Wedler, H; Ridley, P; Langham, S A; McCullagh, B; Bilham, L; Robben, J; Van der Schueren, J; Grymonprez, B; Chuang, Y J; Vandenbussche, F; Braeken, M; Weltjens, I; Voet, M; Bastiaens, I; Aert, R; Defoor, E; Weitzenegger, T; Bothe, G; Ramsperger, U; Hilbert, H; Braun, M; Holzer, E; Brandt, A; Peters, S; van Staveren, M; Dirske, W; Mooijman, P; Klein Lankhorst, R; Rose, M; Hauf, J; Kötter, P; Berneiser, S; Hempel, S; Feldpausch, M; Lamberth, S; Van den Daele, H; De Keyser, A; Buysshaert, C; Gielen, J; Villarroel, R; De Clercq, R; Van Montagu, M; Rogers, J; Cronin, A; Quail, M; Bray-Allen, S; Clark, L; Doggett, J; Hall, S; Kay, M; Lennard, N; McLay, K; Mayes, R; Pettett, A; Rajandream, M A; Lyne, M; Benes, V; Rechmann, S; Borkova, D; Blöcker, H; Scharfe, M; Grimm, M; Löhnert, T H; Dose, S; de Haan, M; Maarse, A; Schäfer, M; Müller-Auer, S; Gabel, C; Fuchs, M; Fartmann, B; Granderath, K; Dauner, D; Herzl, A; Neumann, S; Argiriou, A; Vitale, D; Liguori, R; Piravandi, E; Massenet, O; Quigley, F; Clabauld, G; Mündlein, A; Felber, R; Schnabl, S; Hiller, R; Schmidt, W; Lecharny, A; Aubourg, S; Chefdor, F; Cooke, R; Berger, C; Montfort, A; Casacuberta, E; Gibbons, T; Weber, N; Vandenbol, M; Bargues, M; Terol, J; Torres, A; Perez-Perez, A; Purnelle, B; Bent, E; Johnson, S; Tacon, D; Jesse, T; Heijnen, L; Schwarz, S; Scholler, P; Heber, S; Francs, P; Bielke, C; Frishman, D; Haase, D; Lemcke, K; Mewes, H W; Stocker, S; Zaccaria, P; Bevan, M; Wilson, R K; de la Bastide, M; Habermann, K; Parnell, L; Dedhia, N; Gnoj, L; Schutz, K; Huang, E; Spiegel, L; Sehkon, M; Murray, J; Sheet, P; Cordes, M; Abu-Threideh, J; Stoneking, T; Kalicki, J; Graves, T; Harmon, G; Edwards, J; Latreille, P; Courtney, L; Cloud, J; Abbott, A; Scott, K; Johnson, D; Minx, P; Bentley, D; Fulton, B; Miller, N; Greco, T; Kemp, K; Kramer, J; Fulton, L; Mardis, E; Dante, M; Pepin, K; Hillier, L; Nelson, J; Spieth, J; Ryan, E; Andrews, S; Geisel, C; Layman, D; Du, H; Ali, J; Berghoff, A; Jones, K; Drone, K; Cotton, M; Joshu, C; Antonoiu, B; Zidanic, M; Strong, C; Sun, H; Lamar, B; Yordan, C; Ma, P; Zhong, J; Preston, R; Vil, D; Shekher, M; Matero, A; Shah, R; Swaby, I K; O'Shaughnessy, A; Rodriguez, M; Hoffmann, J; Till, S; Granat, S; Shohdy, N; Hasegawa, A; Hameed, A; Lodhi, M; Johnson, A; Chen, E; Marra, M; Martienssen, R; McCombie, W R

    1999-12-16

    The higher plant Arabidopsis thaliana (Arabidopsis) is an important model for identifying plant genes and determining their function. To assist biological investigations and to define chromosome structure, a coordinated effort to sequence the Arabidopsis genome was initiated in late 1996. Here we report one of the first milestones of this project, the sequence of chromosome 4. Analysis of 17.38 megabases of unique sequence, representing about 17% of the genome, reveals 3,744 protein coding genes, 81 transfer RNAs and numerous repeat elements. Heterochromatic regions surrounding the putative centromere, which has not yet been completely sequenced, are characterized by an increased frequency of a variety of repeats, new repeats, reduced recombination, lowered gene density and lowered gene expression. Roughly 60% of the predicted protein-coding genes have been functionally characterized on the basis of their homology to known genes. Many genes encode predicted proteins that are homologous to human and Caenorhabditis elegans proteins.

  15. Strictly NO3- Nutrition Alleviates Iron Deficiency Chlorosis in Arabidopsis thaliana Plants

    OpenAIRE

    Najoua Msilini; Ines Guesmi; Mohamed Chebbi; Thouraya Amdouni; Mokhtar Lachaвl; Zeineb Ouerghi

    2014-01-01

    The effects of NO3- nutrition on iron deficiency responses were investigated in Arabidopsis thaliana. Plants were grown with or without 5 µM Fe, and with NO3- alone or a mixture of NO3- and NH4+. The results indicated that, NO3- nutrition induced higher dry matter production, regardless the Fe concentration. Fe deficiency reduced growth activity, photosynthetic pigment concentration and Fe content of plants, whatever the N forms. This decrease was more pronounced in plants grown with mixed N ...

  16. Quantitative proteome changes in Arabidopsis thaliana suspension-cultured cells in response to plant natriuretic peptides

    KAUST Repository

    Turek, Ilona

    2015-06-30

    Proteome changes in the Arabidopsis thaliana suspension cells in response to the A. thaliana plant natriuretic peptide (PNP), AtPNP-A (At2g18660) were assessed using quantitative proteomics employing tandem mass tag (TMT) labeling and tandem mass spectrometry (LC–MS/MS). In this study, we characterized temporal responses of suspension-cultured cells to 1 nM and 10 pM AtPNP-A at 0, 10 and 30 min post-treatment. Both concentrations we found to yield a distinct differential proteome signature. The data shown in this article are associated with the article “Plant natriuretic peptides induce a specific set of proteins diagnostic for an adaptive response to abiotic stress” by Turek et al. (Front. Plant Sci. 5 (2014) 661) and have been deposited to the ProteomeXchange with identifier PXD001386.

  17. EFFECTS OF SODIUM NITROPRUSSIDE ON SALT STRESS TOLERANCE OF TOCOPHEROL-DEFICIENT ARABIDOPSIS THALIANA PLANTS

    Directory of Open Access Journals (Sweden)

    Nadiia Mosiichuk

    2015-05-01

    Full Text Available In the present study, effects of exogenous sodium nitroprusside (SNP, a nitric oxide (•NO donor, on lipid peroxidation and antioxidant enzyme activities in wild type and tocopherol-deficient lines vte1 and vte4 of Arabidopsis thaliana subjected to 200 mM NaCl were studied. In wild type plants, pretreatment with SNP did not change level of thiobarbituric acid reactive substances (TBARS, but decreased the activities of dehydroascorbate reductase and guaiacol peroxidase under salt stress. In mutant line vte1, which lacks all forms of tocopherols, pretreatment with SNP reduced TBARS level and increases the activities of glutathione reductase and guaiacol peroxidase under salt stress. Ascorbate peroxidase activity decreased under salt stress conditions in both mutant lines, pretreated with SNP. It can be concluded, that pretreatment with SNP could attenuate salt-induced injuries in A. thaliana plants via up-regulation of activity of antioxidant enzymes and attenuate lipid peroxidation.

  18. Human Norovirus and Its Surrogates Induce Plant Immune Response in Arabidopsis thaliana and Lactuca sativa.

    Science.gov (United States)

    Markland, Sarah M; Bais, Harsh; Kniel, Kalmia E

    2017-08-01

    Human norovirus is the leading cause of foodborne illness worldwide with the majority of outbreaks linked to fresh produce and leafy greens. It is essential that we thoroughly understand the type of relationship and interactions that take place between plants and human norovirus to better utilize control strategies to reduce transmission of norovirus in the field onto plants harvested for human consumption. In this study the expression of gene markers for the salicylic acid (SA) and jasmonic acid (JA) plant defense pathways was measured and compared in romaine lettuce (Lactuca sativa) and Arabidopsis thaliana Col-0 plants that were inoculated with Murine Norovirus-1, Tulane Virus, human norovirus GII.4, or Hank's Balanced Salt Solution (control). Genes involving both the SA and JA pathways were expressed in both romaine lettuce and A. thaliana for all three viruses, as well as controls. Studies, including gene expression of SA- and JA-deficient A. thaliana mutant lines, suggest that the JA pathway is more likely involved in the plant immune response to human norovirus. This research provides the first pieces of information regarding how foodborne viruses interact with plants in the preharvest environment.

  19. Meristem Maintenance in Arabidopsis thaliana

    OpenAIRE

    Para, Alessia

    2004-01-01

    The shoot apical meristem (SAM) is the structure that shapes the aerial architecture of the plant, by producing lateral organs throughout development. In the model plant Arabidopsis thaliana, the SAM is always identifiable as a characteristic dome, whether it is found in the centre of a rosette of leaves or at the tip of an inflorescence. When senescence occurs and organogenesis ceases, the now inactive SAM still retains its characteristic appearance and it is never consumed into a terminal s...

  20. Arabidopsis thaliana peroxidase N

    DEFF Research Database (Denmark)

    Mirza, Osman Asghar; Henriksen, A; Ostergaard, L

    2000-01-01

    The structure of the neutral peroxidase from Arabidopsis thaliana (ATP N) has been determined to a resolution of 1.9 A and a free R value of 20.5%. ATP N has the expected characteristic fold of the class III peroxidases, with a C(alpha) r.m.s.d. of 0.82 A when compared with horseradish peroxidase C...... (HRP C). HRP C is 54% identical to ATP N in sequence. When the structures of four class III plant peroxidases are superimposed, the regions with structural differences are non-randomly distributed; all are located in one half of the molecule. The architecture of the haem pocket of ATP N is very similar...... to that of HRP C, in agreement with the low small-molecule substrate specificity of all class III peroxidases. The structure of ATP N suggests that the pH dependence of the substrate turnover will differ from that of HRP C owing to differences in polarity of the residues in the substrate-access channel. Since...

  1. Phytoremediation of the organic Xenobiotic simazine by p450-1a2 transgenic Arabidopsis thaliana plants.

    Science.gov (United States)

    Azab, Ehab; Hegazy, Ahmad K; El-Sharnouby, Mohamed E; Abd Elsalam, Hassan E

    2016-01-01

    The potential use of human P450-transgenic plants for phytoremediation of pesticide contaminated soils was tested in laboratory and greenhouse experiments. The transgenic P450 CYP1A2 gene Arabidopsis thaliana plants metabolize number of herbicides, insecticides and industrial chemicals. The P450 isozymes CYP1A2 expressed in A. thaliana were examined regarding the herbicide simazine (SIM). Transgenic A. thaliana plants expressing CYP1A2 gene showed significant resistance to SIM supplemented either in plant growth medium or sprayed on foliar parts. The results showed that SIM produces harmful effect on both rosette diameter and primary root length of the wild type (WT) plants. In transgenic A. thaliana lines, the rosette diameter and primary root length were not affected by SIM concentrations used in this experiment. The results indicate that CYP1A2 can be used as a selectable marker for plant transformation, allowing efficient selection of transgenic lines in growth medium and/or in soil-grown plants. The transgenic A. thaliana plants exhibited a healthy growth using doses of up to 250 μmol SIM treatments, while the non-transgenic A. thaliana plants were severely damaged with doses above 50 μmol SIM treatments. The transgenic A. thaliana plants can be used as phytoremediator of environmental SIM contaminants.

  2. Characterization of Plant Growth under Single-Wavelength Laser Light Using the Model Plant Arabidopsis Thaliana

    KAUST Repository

    Ooi, Amanda

    2016-12-01

    Indoor horticulture offers a promising solution for sustainable food production and is becoming increasingly widespread. However, it incurs high energy and cost due to the use of artificial lighting such as high-pressure sodium lamps, fluorescent light or increasingly, the light-emitting diodes (LEDs). The energy efficiency and light quality of currently available lighting is suboptimal, therefore less than ideal for sustainable and cost-effective large-scale plant production. Here, we demonstrate the use of high-powered single-wavelength lasers for indoor horticulture. Lasers are highly energy-efficient and can be remotely guided to the site of plant growth, thus reducing on-site heat accumulation. Besides, laser beams can be tailored to match the absorption profiles of different plants. We have developed a prototype laser growth chamber and demonstrate that laser-grown plants can complete a full growth cycle from seed to seed with phenotypes resembling those of plants grown under LEDs. Importantly, the plants have lower expression of proteins diagnostic for light and radiation stress. The phenotypical, biochemical and proteomic data show that the singlewavelength laser light is suitable for plant growth and therefore, potentially able to unlock the advantages of this next generation lighting technology for highly energy-efficient horticulture. Furthermore, stomatal movement partly determines the plant productivity and stress management. Abscisic acid (ABA) induces stomatal closure by promoting net K+-efflux from guard cells through outwardrectifying K+ (K+ out) channels to regulate plant water homeostasis. Here, we show that the Arabidopsis thaliana guard cell outward-rectifying K+ (ATGORK) channel is a direct target for ABA in the regulation of stomatal aperture and hence gas exchange and transpiration. Addition of (±)-ABA, but not the biologically inactive (−)-isomer, increases K+ out channel activity in Vicia faba guard cell protoplast. A similar ABA

  3. Modified cellulose synthase gene from Arabidopsis thaliana confers herbicide resistance to plants

    Science.gov (United States)

    Somerville, Chris R.; Scheible, Wolf

    2007-07-10

    Cellulose synthase ("CS"), a key enzyme in the biosynthesis of cellulose in plants is inhibited by herbicides comprising thiazolidinones such as 5-tert-butyl-carbamoyloxy-3-(3-trifluromethyl)phenyl-4-thiazolidinone (TZ), isoxaben and 2,6-dichlorobenzonitrile (DCB). Two mutant genes encoding isoxaben and TZ-resistant cellulose synthase have been isolated from isoxaben and TZ-resistant Arabidopsis thaliana mutants. When compared with the gene coding for isoxaben or TZ-sensitive cellulose synthase, one of the resistant CS genes contains a point mutation, wherein glycine residue 998 is replaced by an aspartic acid. The other resistant mutation is due to a threonine to isoleucine change at amino acid residue 942. The mutant CS gene can be used to impart herbicide resistance to a plant; thereby permitting the utilization of the herbicide as a single application at a concentration which ensures the complete or substantially complete killing of weeds, while leaving the transgenic crop plant essentially undamaged.

  4. "Out of pollen" hypothesis for origin of new genes in flowering plants: study from Arabidopsis thaliana.

    Science.gov (United States)

    Wu, Dong-Dong; Wang, Xin; Li, Yan; Zeng, Lin; Irwin, David M; Zhang, Ya-Ping

    2014-09-17

    New genes, which provide material for evolutionary innovation, have been extensively studied for many years in animals where it is observed that they commonly show an expression bias for the testis. Thus, the testis is a major source for the generation of new genes in animals. The source tissue for new genes in plants is unclear. Here, we find that new genes in plants show a bias in expression to mature pollen, and are also enriched in a gene coexpression module that correlates with mature pollen in Arabidopsis thaliana. Transposable elements are significantly enriched in the new genes, and the high activity of transposable elements in the vegetative nucleus, compared with the germ cells, suggests that new genes are most easily generated in the vegetative nucleus in the mature pollen. We propose an "out of pollen" hypothesis for the origin of new genes in flowering plants.

  5. Arabidopsis thaliana glyoxalase 2-1 is required during abiotic stress but is not essential under normal plant growth.

    Directory of Open Access Journals (Sweden)

    Sriram Devanathan

    Full Text Available The glyoxalase pathway, which consists of the two enzymes, GLYOXALASE 1 (GLX 1 (E.C.: 4.4.1.5 and 2 (E.C.3.1.2.6, has a vital role in chemical detoxification. In Arabidopsis thaliana there are at least four different isoforms of glyoxalase 2, two of which, GLX2-1 and GLX2-4 have not been characterized in detail. Here, the functional role of Arabidopsis thaliana GLX2-1 is investigated. Glx2-1 loss-of-function mutants and plants that constitutively over-express GLX2-1 resemble wild-type plants under normal growth conditions. Insilico analysis of publicly available microarray datasets with ATTEDII, Mapman and Genevestigator indicate potential role(s in stress response and acclimation. Results presented here demonstrate that GLX2-1 gene expression is up-regulated in wild type Arabidopsis thaliana by salt and anoxia stress, and by excess L-Threonine. Additionally, a mutation in GLX2-1 inhibits growth and survival during abiotic stresses. Metabolic profiling studies show alterations in the levels of sugars and amino acids during threonine stress in the plants. Elevated levels of polyamines, which are known stress markers, are also observed. Overall our results suggest that Arabidopsis thaliana GLX2-1 is not essential during normal plant life, but is required during specific stress conditions.

  6. Arabidopsis thaliana is a susceptible host plant for the holoparasite Cuscuta spec.

    Science.gov (United States)

    Birschwilks, Mandy; Sauer, Norbert; Scheel, Dierk; Neumann, Stefanie

    2007-10-01

    Arabidopsis thaliana and Cuscuta spec. represent a compatible host-parasite combination. Cuscuta produces a haustorium that penetrates the host tissue. In early stages of development the searching hyphae on the tip of the haustorial cone are connected to the host tissue by interspecific plasmodesmata. Ten days after infection, translocation of the fluorescent dyes, Texas Red (TR) and 5,6-carboxyfluorescein (CF), demonstrates the existence of a continuous connection between xylem and phloem of the host and parasite. Cuscuta becomes the dominant sink in this host-parasite system. Transgenic Arabidopsis plants expressing genes encoding the green fluorescent protein (GFP; 27 kDa) or a GFP-ubiquitin fusion (36 kDa), respectively, under the companion cell (CC)-specific AtSUC2 promoter were used to monitor the transfer of these proteins from the host sieve elements to those of Cuscuta. Although GFP is transferred unimpedly to the parasite, the GFP-ubiquitin fusion could not be detected in Cuscuta. A translocation of the GFP-ubiquitin fusion protein was found to be restricted to the phloem of the host, although a functional symplastic pathway exists between the host and parasite, as demonstrated by the transport of CF. These results indicate a peripheral size exclusion limit (SEL) between 27 and 36 kDa for the symplastic connections between host and Cuscuta sieve elements. Forty-six accessions of A. thaliana covering the entire range of its genetic diversity, as well as Arabidopsis halleri, were found to be susceptible towards Cuscuta reflexa.

  7. Intraspecific plant-soil feedback and intraspecific overyielding in Arabidopsis thaliana.

    Science.gov (United States)

    Bukowski, Alexandra R; Petermann, Jana S

    2014-06-01

    Understanding the mechanisms of community coexistence and ecosystem functioning may help to counteract the current biodiversity loss and its potentially harmful consequences. In recent years, plant-soil feedback that can, for example, be caused by below-ground microorganisms has been suggested to play a role in maintaining plant coexistence and to be a potential driver of the positive relationship between plant diversity and ecosystem functioning. Most of the studies addressing these topics have focused on the species level. However, in addition to interspecific interactions, intraspecific interactions might be important for the structure of natural communities. Here, we examine intraspecific coexistence and intraspecific diversity effects using 10 natural accessions of the model species Arabidopsis thaliana (L.) Heynh. We assessed morphological intraspecific diversity by measuring several above- and below-ground traits. We performed a plant-soil feedback experiment that was based on these trait differences between the accessions in order to determine whether A. thaliana experiences feedback at intraspecific level as a result of trait differences. We also experimentally tested the diversity-productivity relationship at intraspecific level. We found strong differences in above- and below-ground traits between the A. thaliana accessions. Overall, plant-soil feedback occurred at intraspecific level. However, accessions differed in the direction and strength of this feedback: Some accessions grew better on their own soils, some on soils from other accessions. Furthermore, we found positive diversity effects within A. thaliana: Accession mixtures produced a higher total above-ground biomass than accession monocultures. Differences between accessions in their feedback response could not be explained by morphological traits. Therefore, we suggest that they might have been caused by accession-specific accumulated soil communities, by root exudates, or by accession

  8. An Arabidopsis thaliana ABC transporter that confers kanamycin resistance in transgenic plants does not endow resistance to Escherichia coli

    OpenAIRE

    Burris, Kellie; Mentewab, Ayalew; Ripp, Steven; Stewart, C. Neal

    2007-01-01

    Summary Concerns have been raised about potential horizontal gene transfer (HGT) of antibiotic resistance markers (ARMs) from transgenic plants to bacteria of medical and environmental importance. All ARMs used in transgenic plants have been bacterial in origin, but it has been recently shown that an Arabidopsis thaliana ABC transporter, Atwbc19, confers kanamycin resistance when overexpressed in transgenic plants. Atwbc19 was evaluated for its ability to transfer kanamycin resistance to Esch...

  9. Dynamics of male meiotic recombination frequency during plant development using Fluorescent Tagged Lines in Arabidopsis thaliana.

    Science.gov (United States)

    Li, Fan; De Storme, Nico; Geelen, Danny

    2017-02-13

    Meiotic homologous recombination plays a central role in creating genetic variability, making it an essential biological process relevant to evolution and crop breeding. In this study, we used pollen-specific fluorescent tagged lines (FTLs) to measure male meiotic recombination frequency during the development of Arabidopsis thaliana. Interestingly, a subset of pollen grains consistently shows loss of fluorescence expression in tested lines. Using nine independent FTL intervals, the spatio-temporal dynamics of male recombination frequency was assessed during plant development, considering both shoot type and plant age as independent parameters. In most genomic intervals assayed, male meiotic recombination frequency is highly consistent during plant development, showing no significant change between different shoot types and during plant aging. However, in some genomic regions, such as I1a and I5a, a small but significant effect of either developmental position or plant age were observed, indicating that the meiotic CO frequency in those intervals varies during plant development. Furthermore, from an overall view of all nine genomic intervals assayed, both primary and tertiary shoots show a similar dynamics of increasing recombination frequency during development, while secondary and lateral shoots remain highly stable. Our results provide new insights in the dynamics of male meiotic recombination frequency during plant development.

  10. Identification of plant defence regulators through transcriptional profiling of Arabidopsis thaliana cdd1 mutant

    Indian Academy of Sciences (India)

    Swadhin Swain; Nidhi Singh; Ashis Kumar Nandi

    2015-03-01

    A sustainable balance between defence and growth is essential for optimal fitness under pathogen stress. Plants activate immune response at the cost of normal metabolic requirements. Thus, plants that constitutively activate defence are deprived of growth. Arabidopsis thaliana mutant constitutive defence without defect in growth and development1 (cdd1) is an exception. The cdd1 mutant is constitutive for salicylic acid accumulation, signalling, and defence against biotrophic and hemibiotrophic pathogens, without having much impact on growth. Thus, cdd1 offers an ideal genetic background to identify novel regulators of plant defence. Here we report the differential gene expression profile between cdd1 and wild-type plants as obtained by microarray hybridization. Expression of several defence-related genes also supports constitutive activation of defence in cdd1. We screened T-DNA insertion mutant lines of selected genes, for resistance against virulent bacterial pathogen Pseudomonas syringae pv. tomato DC3000 (Pst DC3000). Through bacterial resistance, callose deposition and pathogenesis-associated expression analyses, we identified four novel regulators of plant defence. Resistance levels in the mutants suggest that At2g19810 and [rom] At5g05790 are positive regulators, whereas At1g61370 and At3g42790 are negative regulators of plant defence against bacterial pathogens.

  11. Analysis of the transgenerational iron deficiency stress memory in Arabidopsis thaliana plants.

    Directory of Open Access Journals (Sweden)

    IRENE eMURGIA

    2015-09-01

    Full Text Available We investigated the existence of the transgenerational memory of iron (Fe deficiency stress, in Arabidopsis thaliana. Plants were grown under Fe deficiency/sufficiency, and so were their offspring. The frequency of Somatic Homologous Recombination (SHR events, of DNA strand breaks as well as the expression of the transcription elongation factor TFIIS-like gene increase when plants are grown under Fe deficiency. However, SHR frequency, DNA strand break events and TFIIS-like gene expression do not increase further when plants are grown for more than one generation under the same stress, and furthermore, they decrease back to control values within two succeeding generations grown under control conditions, regardless of the Fe deficiency stress history of the mother plants.Seedlings produced from plants grown under Fe deficiency evolve more oxygen than control seedlings, when grown under Fe sufficiency: however, this trait is not associated with any change in the protein profile of the photosynthetic apparatus and is not transmitted to more than one generation. Lastly, plants grown for multiple generations under Fe deficiency produce seeds with greater longevity: however this trait is not inherited in offspring generations unexposed to stress. These findings suggest the existence of multiple-step control of mechanisms to prevent a genuine and stable transgenerational transmission of Fe deficiency stress memory, with the tightest control on DNA integrity.

  12. Analysis of the transgenerational iron deficiency stress memory in Arabidopsis thaliana plants.

    Science.gov (United States)

    Murgia, Irene; Giacometti, Sonia; Balestrazzi, Alma; Paparella, Stefania; Pagliano, Cristina; Morandini, Piero

    2015-01-01

    We investigated the existence of the transgenerational memory of iron (Fe) deficiency stress, in Arabidopsis thaliana. Plants were grown under Fe deficiency/sufficiency, and so were their offspring. The frequency of somatic homologous recombination (SHR) events, of DNA strand breaks as well as the expression of the transcription elongation factor TFIIS-like gene increase when plants are grown under Fe deficiency. However, SHR frequency, DNA strand break events, and TFIIS-like gene expression do not increase further when plants are grown for more than one generation under the same stress, and furthermore, they decrease back to control values within two succeeding generations grown under control conditions, regardless of the Fe deficiency stress history of the mother plants. Seedlings produced from plants grown under Fe deficiency evolve more oxygen than control seedlings, when grown under Fe sufficiency: however, this trait is not associated with any change in the protein profile of the photosynthetic apparatus and is not transmitted to more than one generation. Lastly, plants grown for multiple generations under Fe deficiency produce seeds with greater longevity: however, this trait is not inherited in offspring generations unexposed to stress. These findings suggest the existence of multiple-step control of mechanisms to prevent a genuine and stable transgenerational transmission of Fe deficiency stress memory, with the tightest control on DNA integrity.

  13. Chromosomal proteins of Arabidopsis thaliana.

    Science.gov (United States)

    Moehs, C P; McElwain, E F; Spiker, S

    1988-07-01

    In plants with large genomes, each of the classes of the histones (H1, H2A, H2B, H3 and H4) are not unique polypeptides, but rather families of closely related proteins that are called histone variants. The small genome and preponderance of single-copy DNA in Arabidopsis thaliana has led us to ask if this plant has such families of histone variants. We have thus isolated histones from Arabidopsis and analyzed them on four polyacrylamide gel electrophoretic systems: an SDS system; an acetic acid-urea system; a Triton transverse gradient system; and a two-dimensional system combining SDS and Triton-acetic acid-urea systems. This approach has allowed us to identify all four of the nucleosomal core histones in Arabidopsis and to establish the existence of a set of H2A and H2B variants. Arabidopsis has at least four H2A variants and three H2B variants of distinct molecular weights as assessed by electrophoretic mobility on SDS-polyacrylamide gels. Thus, Arabidopsis displays a diversity in these histones similar to the diversity displayed by plants with larger genomes such as wheat.The high mobility group (HMG) non-histone chromatin proteins have attracted considerable attention because of the evidence implicating them as structural proteins of transcriptionally active chromatin. We have isolated a group of non-histone chromatin proteins from Arabidopsis that meet the operational criteria to be classed as HMG proteins and that cross-react with antisera to HMG proteins of wheat.

  14. A trio of viral proteins tunes aphid-plant interactions in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Jack H Westwood

    Full Text Available BACKGROUND: Virus-induced deterrence to aphid feeding is believed to promote plant virus transmission by encouraging migration of virus-bearing insects away from infected plants. We investigated the effects of infection by an aphid-transmitted virus, cucumber mosaic virus (CMV, on the interaction of Arabidopsis thaliana, one of the natural hosts for CMV, with Myzus persicae (common names: 'peach-potato aphid', 'green peach aphid'. METHODOLOGY/PRINCIPAL FINDINGS: Infection of Arabidopsis (ecotype Col-0 with CMV strain Fny (Fny-CMV induced biosynthesis of the aphid feeding-deterrent 4-methoxy-indol-3-yl-methylglucosinolate (4MI3M. 4MI3M inhibited phloem ingestion by aphids and consequently discouraged aphid settling. The CMV 2b protein is a suppressor of antiviral RNA silencing, which has previously been implicated in altering plant-aphid interactions. Its presence in infected hosts enhances the accumulation of CMV and the other four viral proteins. Another viral gene product, the 2a protein (an RNA-dependent RNA polymerase, triggers defensive signaling, leading to increased 4MI3M accumulation. The 2b protein can inhibit ARGONAUTE1 (AGO1, a host factor that both positively-regulates 4MI3M biosynthesis and negatively-regulates accumulation of substance(s toxic to aphids. However, the 1a replicase protein moderated 2b-mediated inhibition of AGO1, ensuring that aphids were deterred from feeding but not poisoned. The LS strain of CMV did not induce feeding deterrence in Arabidopsis ecotype Col-0. CONCLUSIONS/SIGNIFICANCE: Inhibition of AGO1 by the 2b protein could act as a booby trap since this will trigger antibiosis against aphids. However, for Fny-CMV the interplay of three viral proteins (1a, 2a and 2b appears to balance the need of the virus to inhibit antiviral silencing, while inducing a mild resistance (antixenosis that is thought to promote transmission. The strain-specific effects of CMV on Arabidopsis-aphid interactions, and differences

  15. Arabidopsis thaliana plant defensin AtPDF1.1 is involved in the plant response to biotic stress.

    Science.gov (United States)

    De Coninck, Barbara M A; Sels, Jan; Venmans, Esther; Thys, Wannes; Goderis, Inge J W M; Carron, Delphine; Delauré, Stijn L; Cammue, Bruno P A; De Bolle, Miguel F C; Mathys, Janick

    2010-09-01

    *Previously, it was shown that the Arabidopsis thaliana plant defensins AtPDF1.1 (At1g75830) and AtPDF1.2a (At5g44420) exert in vitro antimicrobial properties and that their corresponding genes are expressed in seeds and induced in leaves upon pathogen attack, respectively. *In this study, the expression profile of both AtPDF1.1 and AtPDF1.2a is analysed in wild-type plants upon different stress-related treatments and the effect of modulation of their expression in transgenic plants is examined in both host and nonhost resistance. *AtPDF1.1, which was originally considered to be seed-specific, is demonstrated to be locally induced in leaves upon fungal attack and exhibits an expression profile distinct from that of AtPDF1.2a, a gene frequently used as marker for the ethylene/jasmonate-mediated signaling pathway. Transgenic plants with modulated AtPDF1.1 or AtPDF1.2a gene expression show no altered phenotype upon Botrytis cinerea inoculation. However, constitutive overexpression of AtPDF1.1 in A. thaliana leads to a reduction in symptoms caused by the nonhost Cercospora beticola causing non-spreading spots on A. thaliana leaves. *These results indicate that AtPDF1.1 and AtPDF1.2a clearly differ regarding their expression profile and functionality in planta. It emphasizes the additional level of complexity and fine-tuning within the highly redundant plant defensin genes in A. thaliana.

  16. Metabolite profiling of Arabidopsis thaliana (L.) plants transformed with an antisense chalcone synthase gene

    DEFF Research Database (Denmark)

    Le Gall, G.; Metzdorff, Stine Broeng; Pedersen, Jan W.;

    2005-01-01

    A metabolite profiling study has been carried out on Arabidopsis thaliana (L.) Heynh. ecotype Wassilewskija and a series of transgenic lines of the ecotype transformed with a CHS (chalcone synthase) antisense construct. Compound identifications by LC/MS and H-1 NMR are discussed. The glucosinolate...

  17. Identification and Expression Profiling of Radiation-sensitive Genes Using Plant Model System, Arabidopsis thaliana

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong-Sub; Kang, Si-Yong; Lee, Geung-Joo; Kim, Jin-Baek

    2008-06-15

    The purpose of this study is to characterize genes specifically expressed in response to ionizing energy (gamma-rays) of acute irradiation and elucidate signalling mechanisms via functional analysis of isolated genes in Arabidopsis thaliana. Recent improvements in DNA microarray technologies and bioinformatics have made it possible to look for common features of ionizing radiation-responsive genes and their regulatory regions. It has produced massive quantities of gene expression and other functional genomics data, and its application will increase in plant genomics. In this study, we used oligonucleotide microarrays to detect the Arabidopsis genes expressed differentially by a gamma-irradiation during the vegetative (VT, 21 DAG) and reproductive (RT, 28 DAG) stages. Wild-type (Ler) Arabidopsis was irradiated with gamma-rays with 100 and 800 Gy doses. Among the 21,500 genes represented in the Agilent chip, approximately 13,500 ({sup {approx}}61.4 %) responsive genes to {nu} -irradiation were expressed with signal intensity greater than 192 when compared to the combined control (non-irradiated vegetative and reproductive pool). Expression patterns of several radiation inducible genes were confirmed by RT-PCR and Northern blotting. Our microarray results may contribute to an overall understanding of the type and quantities of genes that are expressed by an acute gamma-irradiation. In addition, to investigate the oxidative damage caused by irradiation, RT-PCR analysis for the expression of antioxidant isoenzyme genes, and a Transmission Electron Microscope (TEM) observation for visualizing the H{sub 2}O{sub 2} scavenging activity in leaves were applied.

  18. Modified cellulose synthase gene from 'Arabidopsis thaliana' confers herbicide resistance to plants

    Energy Technology Data Exchange (ETDEWEB)

    Somerville, Chris R.; Scieble, Wolf

    2000-10-11

    Cellulose synthase ('CS'), a key enzyme in the biosynthesis of cellulose in plants is inhibited by herbicides comprising thiazolidinones such as 5-tert-butyl-carbamoyloxy-3-(3-trifluromethyl) phenyl-4-thiazolidinone (TZ), isoxaben and 2,6-dichlorobenzonitrile (DCB). Two mutant genes encoding isoxaben and TZ-resistant cellulose synthase have been isolated from isoxaben and TZ-resistant Arabidopsis thaliana mutants. When compared with the gene coding for isoxaben or TZ-sensitive cellulose synthase, one of the resistant CS genes contains a point mutation, wherein glycine residue 998 is replaced by an aspartic acid. The other resistant mutation is due to a threonine to isoleucine change at amino acid residue 942. The mutant CS gene can be used to impart herbicide resistance to a plant; thereby permitting the utilization of the herbicide as a single application at a concentration which ensures the complete or substantially complete killing of weeds, while leaving the transgenic crop plant essentially undamaged.

  19. Overexpression of the phytochrome B gene from Arabidopsis thaliana increases plant growth and yield of cotton (Gossypium hirsutum)

    Institute of Scientific and Technical Information of China (English)

    Abdul Qayyum RAO; Muhammad IRFAN; Zafar SALEEM; Idrees Ahmad NASIR; Sheikh RIAZUDDIN; Tayyab HUSNAIN

    2011-01-01

    The phytochrome B (PHYB) gene of Arabidopsis thaliana was introduced into cotton through Agrobacterium tumefaciens. Integration and expression of PHYB gene in cotton plants were confirmed by molecular evidence.Messenger RNA (mRNA) expression in one of the transgenic lines, QCC11, was much higher than those of control and other transgenic lines. Transgenic cotton plants showed more than a two-fold increase in photosynthetic rate and more than a four-fold increase in transpiration rate and stomatal conductance. The increase in photosynthetic rate led to a 46% increase in relative growth rate and an 18% increase in net assimilation rate. Data recorded up to two generations,both in the greenhouse and in the field, revealed that overexpression ofArabidopsis thaliana PHYB gene in transgeniccotton plants resulted in an increase in the production of cotton by improving the cotton plant growth, with 35% more yield. Moreover, the presence of the Arabidopsis thaliana PHYB gene caused pleiotropic effects like semi-dwarfism,decrease in apical dominance, and increase in boll size.

  20. Steroid-inducible BABY BOOM system for development of fertile Arabidopsis thaliana plants after prolonged tissue culture.

    Science.gov (United States)

    Lutz, Kerry A; Martin, Carla; Khairzada, Sahar; Maliga, Pal

    2015-10-01

    We describe a steroid-inducible BABY BOOM system that improves plant regeneration in Arabidopsis leaf cultures and yields fertile plants. Regeneration of Arabidopsis thaliana plants for extended periods of time in tissue culture may result in sterile plants. We report here a novel approach for A. thaliana regeneration using a regulated system to induce embryogenic cultures from leaf tissue. The system is based on BABY BOOM (BBM), a transcription factor that turns on genes involved in embryogenesis. We transformed the nucleus of A. thaliana plants with BBM:GR, a gene in which the BBM coding region is fused with the glucocorticoid receptor (GR) steroid-binding domain. In the absence of the synthetic steroid dexamethasone (DEX), the BBM:GR fusion protein is localized in the cytoplasm. Only when DEX is included in the culture medium does the BBM transcription factor enter the nucleus and turn on genes involved in embryogenesis. BBM:GR plant lines show prolific shoot regeneration from leaf pieces on media containing DEX. Removal of DEX from the culture media allowed for flowering and seed formation. Therefore, use of BBM:GR leaf tissue for regeneration of plants for extended periods of time in tissue culture will facilitate the recovery of fertile plants.

  1. Complexes with mixed primary and secondary cellulose synthases are functional in Arabidopsis thaliana plants

    Energy Technology Data Exchange (ETDEWEB)

    Carroll, Andrew; Mansoori, N; Li, Shundai; Lei, Lei; Vernhettes, Samantha; Visser, Richard G. F.; Somerville, Chris R; Gu, Ying; Trindade, Luisa M.

    2012-10-01

    In higher plants, cellulose is synthesized by so-called rosette protein complexes with cellulose synthases (CESAs) as catalytic subunits of the complex. The CESAs are divided into two distinct families, three of which are thought to be specialized for the primary cell wall and three for the secondary cell wall. In this article, the potential of primary and secondary CESAs forming a functional rosette complex has been investigated. The membrane-based yeast two-hybrid and biomolecular fluorescence systems were used to assess the interactions between three primary (CESA1, CESA3, CESA6), and three secondary (CESA4, CESA7, CESA8) Arabidopsis (Arabidopsis thaliana) CESAs. The results showed that all primary CESAs can physically interact both in vitro and in planta with all secondary CESAs. Although CESAs are broadly capable of interacting in pairwise combinations, they are not all able to form functional complexes in planta. Analysis of transgenic lines showed that CESA7 can partially rescue defects in the primary cell wall biosynthesis in a weak cesa3 mutant. Green fluorescent protein-CESA protein fusions revealed that when CESA3 was replaced by CESA7 in the primary rosette, the velocity of the mixed complexes was slightly faster than the native primary complexes. CESA1 in turn can partly rescue defects in secondary cell wall biosynthesis in a cesa8ko mutant, resulting in an increase of cellulose content relative to cesa8ko. These results demonstrate that sufficient parallels exist between the primary and secondary complexes for cross-functionality and open the possibility that mixed complexes of primary and secondary CESAs may occur at particular times.

  2. Treatment of Arabidopsis thaliana seeds with an HSP90 inhibitor increases plant resistance

    Science.gov (United States)

    Kozeko, Liudmyla

    2016-07-01

    Resistance of plants to unfavourable conditions is an important feature to use them as an autotrophic link of Life Support Systems in space exploration missions. It significantly depends on basic and stress-induced levels of heat shock proteins (HSP) in cells. It is known that HSP90 can bind and maintain heat shock transcription factors (HSF) as a monomer that lacks DNA binding activity and thereby regulate HSP expression. Modulation of activity of the HSP synthesis and resistance by HSP90 in plants is not well investigated. The objective of this study was to determine how treatment of seeds with an HSP90 inhibitor affects environmental responsiveness in Arabidopsis thaliana. Seed treatment with geldanamycin (GDA) was used to reduce HSP90 function. The affect of space flight stressors was simulated by gamma-irradiation and thermal upshift. Two series of experiments were carried out: 1) exposure of dry seeds to gamma-irradiation (1 kGy, ^{60}Co); 2) heat shock of seedlings. It was shown that GDA treatment of seeds stimulated the seedling growth after seed irradiation. It also increased both the basic thermotolerance (45°C for 45 min) and induced thermotolerance (45°C for 1,5-2,5 h after pretreatment at 37°C for 2 h) in seedlings. In addition, seed treatment with GDA had a prolonged effect on the HSP70 production in seedlings under normal and stressful conditions. It shows that the stimulatory effects of GDA may be caused by induction of HSP70 synthesis. The obtained data demonstrate that pre-treatment of seeds with GDA before planting allows inducing the stress resistance at least at early growth stages of plants.

  3. Prediction of Plant Height in Arabidopsis thaliana Using DNA Methylation Data

    Science.gov (United States)

    Hu, Yaodong; Morota, Gota; Rosa, Guilherme J. M.; Gianola, Daniel

    2015-01-01

    Prediction of complex traits using molecular genetic information is an active area in quantitative genetics research. In the postgenomic era, many types of -omic (e.g., transcriptomic, epigenomic, methylomic, and proteomic) data are becoming increasingly available. Therefore, evaluating the utility of this massive amount of information in prediction of complex traits is of interest. DNA methylation, the covalent change of a DNA molecule without affecting its underlying sequence, is one quantifiable form of epigenetic modification. We used methylation information for predicting plant height (PH) in Arabidopsis thaliana nonparametrically, using reproducing kernel Hilbert spaces (RKHS) regression. Also, we used different criteria for selecting smaller sets of probes, to assess how representative probes could be used in prediction instead of using all probes, which may lessen computational burden and lower experimental costs. Methylation information was used for describing epigenetic similarities between individuals through a kernel matrix, and the performance of predicting PH using this similarity matrix was reasonably good. The predictive correlation reached 0.53 and the same value was attained when only preselected probes were used for prediction. We created a kernel that mimics the genomic relationship matrix in genomic best linear unbiased prediction (G-BLUP) and estimated that, in this particular data set, epigenetic variation accounted for 65% of the phenotypic variance. Our results suggest that methylation information can be useful in whole-genome prediction of complex traits and that it may help to enhance understanding of complex traits when epigenetics is under examination. PMID:26253546

  4. The pharmaceutics from the foreign empire: the molecular pharming of the prokaryotic staphylokinase in Arabidopsis thaliana plants.

    Science.gov (United States)

    Hnatuszko-Konka, Katarzyna; Łuchniak, Piotr; Wiktorek-Smagur, Aneta; Gerszberg, Aneta; Kowalczyk, Tomasz; Gatkowska, Justyna; Kononowicz, Andrzej K

    2016-07-01

    Here, we present the application of microbiology and biotechnology for the production of recombinant pharmaceutical proteins in plant cells. To the best of our knowledge and belief it is one of few examples of the expression of the prokaryotic staphylokinase (SAK) in the eukaryotic system. Despite the tremendous progress made in the plant biotechnology, most of the heterologous proteins still accumulate to low concentrations in plant tissues. Therefore, the composition of expression cassettes to assure economically feasible level of protein production in plants remains crucial. The aim of our research was obtaining a high concentration of the bacterial anticoagulant factor-staphylokinase, in Arabidopsis thaliana seeds. The coding sequence of staphylokinase was placed under control of the β-phaseolin promoter and cloned between the signal sequence of the seed storage protein 2S2 and the carboxy-terminal KDEL signal sequence. The engineered binary vector pATAG-sak was introduced into Arabidopsis thaliana plants via Agrobacterium tumefaciens-mediated transformation. Analysis of the subsequent generations of Arabidopsis seeds revealed both presence of the sak and nptII transgenes, and the SAK protein. Moreover, a plasminogen activator activity of staphylokinase was observed in the protein extracts from seeds, while such a reaction was not observed in the leaf extracts showing seed-specific activity of the β-phaseolin promoter.

  5. Expression of the dspA/E gene of Erwinia amylovora in non-host plant Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Hasan Murat Aksoy

    2017-01-01

    Full Text Available In the Erwinia amylovora genome, the hrp gene cluster containing the dspA/E/EB/F operon plays a crucial role in mediating the pathogenicity and the hypersensitive response (HR in the host plant. The role of the dspA/E gene derived from E. amylovora was investigated by monitoring the expression of the β-glucuronidase (GUS reporter system in transgenic Arabidopsis thaliana cv. Pri-Gus seedlings. A mutant ΔdspA/E strain of E. amylovora was generated to contain a deletion of the dspA/E gene for the purpose of this study. Two-week-old seedlings of GUS transgenic Arabidopsis were vacuum-infiltrated with the wild-type and the mutant (ΔdspA/E E. amylovora strains. The Arabidopsis seedlings were fixed and stained for GUS activity after 3–5 days following infiltration. The appearance of dense spots with blue staining on the Arabidopsis leaves indicated the typical characteristic of GUS activity. This observation indicated that the wild-type E. amylovora strain had induced a successful and efficient infection on the A. thaliana Pri-Gus leaves. In contrast, there was no visible GUS expression on leaf tissues which were inoculated with the ΔdspA/E mutant E. amylovora strain. These results indicate that the dspA/E gene is required by the bacterial cells to induce HR in non-host plants.

  6. Dynamic changes in plant secondary metabolites during UV acclimation in Arabidopsis thaliana.

    Science.gov (United States)

    Hectors, Kathleen; Van Oevelen, Sandra; Geuns, Jan; Guisez, Yves; Jansen, Marcel A K; Prinsen, Els

    2014-10-01

    Plants respond to environmental stress by synthesizing a range of secondary metabolites for defense purposes. Here we report on the effect of chronic ultraviolet (UV) radiation on the accumulation of plant secondary metabolites in Arabidopsis thaliana leaves. In the natural environment, UV is a highly dynamic environmental parameter and therefore we hypothesized that plants are continuously readjusting levels of secondary metabolites. Our data show distinct kinetic profiles for accumulation of tocopherols, polyamines and flavonoids upon UV acclimation. The lipid-soluble antioxidant α-tocopherol accumulated fast and remained elevated. Polyamines accumulated fast and transiently. This fast response implies a role for α-tocopherol and polyamines in short-term UV response. In contrast, an additional sustained accumulation of flavonols took place. The distinct accumulation patterns of these secondary metabolites confirm that the UV acclimation process is a dynamic process, and indicates that commonly used single time-point analyses do not reveal the full extent of UV acclimation. We demonstrate that UV stimulates the accumulation of specific flavonol glycosides, i.e. kaempferol and (to a lesser extent) quercetin di- and triglycosides, all specifically rhamnosylated at position seven. All metabolites were identified by Ultra Performance Liquid Chromatography (UPLC)-coupled tandem mass spectrometry. Some of these flavonol glycosides reached steady-state levels in 3-4 days, while concentrations of others are still increasing after 12  days of UV exposure. A biochemical pathway for these glycosides is postulated involving 7-O-rhamnosylation for the synthesis of all eight metabolites identified. We postulate that this 7-O-rhamnosylation has an important function in UV acclimation.

  7. Perturbations in the Primary Metabolism of Tomato and Arabidopsis thaliana Plants Infected with the Soil-Borne Fungus Verticillium dahliae.

    Directory of Open Access Journals (Sweden)

    Anja Buhtz

    Full Text Available The hemibiotrophic soil-borne fungus Verticillium dahliae is a major pathogen of a number of economically important crop species. Here, the metabolic response of both tomato and Arabidopsis thaliana to V. dahliae infection was analysed by first using non-targeted GC-MS profiling. The leaf content of both major cell wall components glucuronic acid and xylose was reduced in the presence of the pathogen in tomato but enhanced in A. thaliana. The leaf content of the two tricarboxylic acid cycle intermediates fumaric acid and succinic acid was increased in the leaf of both species, reflecting a likely higher demand for reducing equivalents required for defence responses. A prominent group of affected compounds was amino acids and based on the targeted analysis in the root, it was shown that the level of 12 and four free amino acids was enhanced by the infection in, respectively, tomato and A. thaliana, with leucine and histidine being represented in both host species. The leaf content of six free amino acids was reduced in the leaf tissue of diseased A. thaliana plants, while that of two free amino acids was raised in the tomato plants. This study emphasizes the role of primary plant metabolites in adaptive responses when the fungus has colonized the plant.

  8. Studies on gene expressions analyses for Arabidopsis thaliana plants stimulated by space flight condition

    Science.gov (United States)

    Lu, Jinying; Liu, Min; Pan, Yi; Li, Huasheng

    We carried out whole-genome microarray to screen the transcript profile of Arabidopsis thaliana seedlings after three treatment: space microgravity condition( Seedlings grown in microgravity state of space flight of SIMBOX on Shenzhou-8), 1g centrifugal force in space(Seedlings grown in 1g centrifugal force state of space flight of SIMBOX on Shenzhou-8) and ground control. The result of microarray analysis is as followed: There were 368 genes significantly differentially expressed in space microgravity condition compared with that in 1g centrifuge space condition. Space radiation caused 246 genes significantly differentially expressed between seedlings in 1g centrifuge space condition and ground control. Space conditions (including microgravity and radiation) caused 621 genes significantly differentially expressed between seedlings in space microgravity condition and ground control. Microgravity and radiation as a single factor can cause plant gene expression change, but two factors synergism can produce some new effects on plant gene expression. The function of differential expression genes were analyst by bioinformatics, and we found the expression of genes related with stress were more different, such as the dehydration of protein (dehydrin Xero2) expression is up-regulated 57 times; low-temperature-induced protein expression is up-regulated in 49 times; heat shock protein expression is up-regulated 20 times; transcription factor DREB2A expression increase 25 times; protein phosphatase 2C expression is up-regulated 14 times; transcription factor NAM-like protein expression is up-regulated 13 times; cell wall metabolism related genes (xyloglucan, endo-1, 4-beta-D-glucanase) expression is down-regulated in 15 times. The results provide scientific data for the mechanism of space mutation.

  9. Plant performance: a physiological and genetic analysis using Arabidopsis thaliana natural variation

    NARCIS (Netherlands)

    El-Lithy, M.E.M.

    2005-01-01

    Plant performance implies complex traits, controlled by a large set of genes and affected by the environment. In this thesis we have tried to take the first steps in unravelling the genes controlling plant performance using naturally occurring accessions (ecotypes) of the model plant Arabidopsis

  10. The predominantly selfing plant Arabidopsis thaliana experienced a recent reduction in transposable element abundance compared to its outcrossing relative Arabidopsis lyrata

    Directory of Open Access Journals (Sweden)

    de la Chaux Nicole

    2012-02-01

    Full Text Available Abstract Background Transposable elements (TEs are major contributors to genome evolution. One factor that influences their evolutionary dynamics is whether their host reproduces through selfing or through outcrossing. According to the recombinational spreading hypothesis, for instance, TEs can spread more easily in outcrossing species through recombination, and should thus be less abundant in selfing species. We here studied the distribution and evolutionary dynamics of TE families in the predominantly selfing plant Arabidopsis thaliana and its close outcrossing relative Arabidopsis lyrata on a genome-wide scale. We characterized differences in TE abundance between them and asked which, if any, existing hypotheses about TE abundances may explain these differences. Results We identified 1,819 TE families representing all known classes of TEs in both species, and found three times more copies in the outcrossing A. lyrata than in the predominantly selfing A. thaliana, as well as ten times more TE families unique to A. lyrata. On average, elements in A. lyrata are younger than elements in A. thaliana. In particular, A. thaliana shows a marked decrease in element number that occurred during the most recent 10% of the time interval since A. thaliana split from A. lyrata. This most recent period in the evolution of A. thaliana started approximately 500,000 years ago, assuming a splitting time of 5 million years ago, and coincides with the time at which predominant selfing originated. Conclusions Our results indicate that the mating system may be important for determining TE copy number, and that selfing species are likely to have fewer TEs.

  11. S-methylmethionine is involved in the salinity tolerance of Arabidopsis thaliana plants at germination and early growth stages.

    Science.gov (United States)

    Ogawa, Saori; Mitsuya, Shiro

    2012-01-01

    Methionine (Met) is biosynthesized by the activated methyl cycle and S-methylmethionine (SMM) cycle in one-carbon (C1) metabolism in plants. It is converted to S-adenosylmethionine (SAM) which serves as a precursor for many metabolites including glycinebetaine, methylated polyols, polyamines and ethylene which accumulate in plants in response to salinity. We have investigated how the Met biosynthetic pathway is regulated under saline conditions at the transcriptional level in Arabidopsis thaliana plants. Within Met biosynthesis-related genes, the expression of homocysteine methyltransferase (HMT) and methionine methyltransferase (MMT) genes in SMM cycle had altered toward increasing Met production by the presence of NaCl. We have determined the salinity tolerance of an Arabidopsis mmt mutant with an insertional mutation in the single copy of the AtMMT gene. Although the mmt mutant showed comparable germination and shoot growth with wild type under normal conditions, NaCl treatment caused severe repression of germination rate and shoot growth in the mmt mutant compared with in the wild type. These results indicate that the utilization of SMM is important for the salinity tolerance of Arabidopsis plants at the germination and early growth stages.

  12. Expression of Helicobacter pylori TonB protein in transgenic Arabidopsis thaliana: toward production of vaccine antigens in plants.

    Science.gov (United States)

    Kalbina, Irina; Engstrand, Lars; Andersson, Sören; Strid, Ake

    2010-10-01

    The aim of this study was to produce a recombinant version of the highly antigenic Helicobacter pylori TonB (iron-dependent siderophore transporter protein HP1341) in transgenic plants as a candidate oral vaccine antigen. Using Agrobacterium-mediated gene transfer, we introduced three different constructs of the tonB gene into the genome of the model plant Arabidopsis thaliana. We investigated transgene insertion by PCR, produced TonB antibodies for analysis of the production of the recombinant protein in plants, verified the identity of the protein produced by mass spectrometry analysis, and analyzed the number of genetic inserts in the plants by Southern blotting. Three different constructs of the expression cassette (full-length tonB, tonB truncated in the 5' end removing the codons for a transmembrane helix, and the latter construct with codons for the endoplasmic reticulum SEKDEL retention signal added to the 3' end) were used to find the most effective way to express the TonB antigen. Production of TonB protein was detected in plants transformed with each of the constructs, confirmed by both Western blotting and mass spectrometry analysis. No considerable differences in protein expression from the three different constructs were observed. The protein concentration in the plants was at least 0.05% of the total soluble proteins. The Helicobacter pylori TonB protein can be produced in Arabidopsis thaliana plants in a form that is recognizable by rabbit anti-TonB antiserum. These TonB-expressing plants are highly suitable for animal studies of oral administration as a route for immunization against Helicobacter infections. © 2010 Blackwell Publishing Ltd.

  13. Arabidopsis thaliana natural variation reveals connections between UV radiation stress and plant pathogen-like defense responses.

    Science.gov (United States)

    Piofczyk, Thomas; Jeena, Ganga; Pecinka, Ales

    2015-08-01

    UV radiation is a ubiquitous component of solar radiation that affects plant growth and development. Here we studied growth related traits of 345 Arabidopsis thaliana accessions in response to UV radiation stress. We analyzed the genetic basis of this natural variation by genome-wide association studies, which suggested a specific candidate genomic region. RNA-sequencing of three sensitive and three resistant accessions combined with mutant analysis revealed five large effect genes. Mutations in PHE ammonia lyase 1 (PAL1) and putative kinase At1g76360 rendered Arabidopsis hypersensitive to UV stress, while loss of function from putative methyltransferase At4g22530, novel plant snare 12 (NPSN12) and defense gene activated disease resistance 2 (ADR2) conferred higher UV stress resistance. Three sensitive accessions showed strong ADR2 transcriptional activation, accumulation of salicylic acid (SA) and dwarf growth upon UV stress, while these phenotypes were much less affected in resistant plants. The phenotype of sensitive accessions resembles autoimmune reactions due to overexpression of defense related genes, and suggests that natural variation in response to UV radiation stress is driven by pathogen-like responses in Arabidopsis.

  14. Arabidopsis thaliana plants expressing human beta-defensin-2 are more resistant to fungal attack: functional homology between plant and human defensins.

    Science.gov (United States)

    Aerts, An M; Thevissen, Karin; Bresseleers, Sara M; Sels, Jan; Wouters, Piet; Cammue, Bruno P A; François, Isabelle E J A

    2007-08-01

    Human beta-defensin-2 (hBD-2) is a small antimicrobial peptide with potent activity against different Gram-negative bacteria and fungal/yeast species. Since human beta-defensins and plant defensins share structural homology, we set out to analyse whether there also exists a functional homology between these defensins of different eukaryotic kingdoms. To this end, we constructed a plant transformation vector harbouring the hBD-2 coding sequence, which we transformed to Arabidopsis thaliana plants, giving rise to A. thaliana plants indeed expressing hBD-2. Furthermore, we could demonstrate that this heterologously produced hBD-2 possesses antifungal activity in vitro. Finally, we could show that hBD-2 expressing A. thaliana plants are more resistant against the broad-spectrum fungal pathogen Botrytis cinerea as compared to untransformed A. thaliana plants, and that this resistance is correlated with the level of active hBD-2 produced in these transgenic plants. Hence, we demonstrated a functional homology, next to the already known structural homology, between defensins originating from different eukaryotic kingdoms. To our knowledge, this is the first time that this is specifically demonstrated for plant and mammalian defensins.

  15. The allotetraploid Arabidopsis thaliana-Arabidopsis lyrata subsp. petraea as an alternative model system for the study of polyploidy in plants.

    Science.gov (United States)

    Beaulieu, Julien; Jean, Martine; Belzile, François

    2009-04-01

    Polyploidy is known to be common in plants and recent work has focused on the rapid changes in genome structure and expression that occur upon polyploidization. In Arabidopsis, much of this work has been done on a synthetic allotetraploid obtained by crossing a tetraploid Arabidopsis thaliana (2n = 4x = 20) with A. arenosa (2n = 4x = 32). To explore an alternative route to polyploidy in this model species, we have developed a synthetic allopolyploid by crossing two diploid species: A. thaliana (2n = 2x = 10) and Arabidopsis lyrata subsp. petraea (2n = 2x = 16). F(1) hybrids were easy to obtain and phenotypically more similar to A. lyrata. Spontaneous chromosome doubling events occurred in about 25% of the F(1)s, thus restoring fertility. The resulting allotetraploids (2n = 26) exhibited many genomic changes typically reported upon polyploidization. Nucleolar dominance was observed as only the A. lyrata rDNA loci were expressed in the F(1) and allotetraploids. Changes in the degree of methylation were observed at almost 25% of the loci examined by MSAP analysis. Finally, structural genomic alterations did occur as a large deletion covering a significant portion of the upper arm of chromosome II was detected but no evidence of increased mobility of transposons was obtained. Such allotetraploids derived from two parents with sequenced (or soon to be sequenced) genomes offer much promise in elucidating the various changes that occur in newly synthesized polyploids.

  16. Effects of the plant growth-promoting bacterium Burkholderia phytofirmans PsJN throughout the life cycle of Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    María Josefina Poupin

    Full Text Available Plant growth-promoting rhizobacteria (PGPR induce positive effects in plants, such as increased growth or reduced stress susceptibility. The mechanisms behind PGPR/plant interaction are poorly understood, as most studies have described short-term responses on plants and only a few studies have analyzed plant molecular responses under PGPR colonization. Here, we studied the effects of the PGPR bacterial model Burkholderiaphytofirmans PsJN on the whole life cycle of Arabidopsis thaliana plants. We reported that at different plant developmental points, strain PsJN can be found in the rhizosphere and also colonizing their internal tissues. In early ontogeny, strain PsJN increased several growth parameters and accelerated growth rate of the plants. Also, an Arabidopsis transcriptome analysis revealed that 408 genes showed differential expression in PsJN-inoculated plants; some of these genes are involved in stress response and hormone pathways. Specifically, genes implicated in auxin and gibberellin pathways were induced. Quantitative transcriptional analyses of selected genes in different developmental stages revealed that the beginning of these changes could be evidenced early in development, especially among the down-regulated genes. The inoculation with heat-killed bacteria provoked a more severe transcriptional response in plants, but was not able to induce plant growth-promotion. Later in ontogeny, the growth rates of inoculated plants decreased with respect to the non-inoculated group and, interestingly, the inoculation accelerated the flowering time and the appearance of senescence signs in plants; these modifications correlate with the early up-regulation of flowering control genes. Then, we show that a single inoculation with a PGPR could affect the whole life cycle of a plant, accelerating its growth rate and shortening its vegetative period, both effects relevant for most crops. Thus, these findings provide novel and interesting aspects

  17. A Cold-Inducible DEAD-Box RNA Helicase from Arabidopsis thaliana Regulates Plant Growth and Development under Low Temperature.

    Directory of Open Access Journals (Sweden)

    Yuelin Liu

    Full Text Available DEAD-box RNA helicases comprise a large family and are involved in a range of RNA processing events. Here, we identified one of the Arabidopsis thaliana DEAD-box RNA helicases, AtRH7, as an interactor of Arabidopsis COLD SHOCK DOMAIN PROTEIN 3 (AtCSP3, which is an RNA chaperone involved in cold adaptation. Promoter:GUS transgenic plants revealed that AtRH7 is expressed ubiquitously and that its levels of the expression are higher in rapidly growing tissues. Knockout mutant lines displayed several morphological alterations such as disturbed vein pattern, pointed first true leaves, and short roots, which resemble ribosome-related mutants of Arabidopsis. In addition, aberrant floral development was also observed in rh7 mutants. When the mutants were germinated at low temperature (12°C, both radicle and first leaf emergence were severely delayed; after exposure of seedlings to a long period of cold, the mutants developed aberrant, fewer, and smaller leaves. RNA blots and circular RT-PCR revealed that 35S and 18S rRNA precursors accumulated to higher levels in the mutants than in WT under both normal and cold conditions, suggesting the mutants are partially impaired in pre-rRNA processing. Taken together, the results suggest that AtRH7 affects rRNA biogenesis and plays an important role in plant growth under cold.

  18. A Cold-Inducible DEAD-Box RNA Helicase from Arabidopsis thaliana Regulates Plant Growth and Development under Low Temperature.

    Science.gov (United States)

    Liu, Yuelin; Tabata, Daisuke; Imai, Ryozo

    2016-01-01

    DEAD-box RNA helicases comprise a large family and are involved in a range of RNA processing events. Here, we identified one of the Arabidopsis thaliana DEAD-box RNA helicases, AtRH7, as an interactor of Arabidopsis COLD SHOCK DOMAIN PROTEIN 3 (AtCSP3), which is an RNA chaperone involved in cold adaptation. Promoter:GUS transgenic plants revealed that AtRH7 is expressed ubiquitously and that its levels of the expression are higher in rapidly growing tissues. Knockout mutant lines displayed several morphological alterations such as disturbed vein pattern, pointed first true leaves, and short roots, which resemble ribosome-related mutants of Arabidopsis. In addition, aberrant floral development was also observed in rh7 mutants. When the mutants were germinated at low temperature (12°C), both radicle and first leaf emergence were severely delayed; after exposure of seedlings to a long period of cold, the mutants developed aberrant, fewer, and smaller leaves. RNA blots and circular RT-PCR revealed that 35S and 18S rRNA precursors accumulated to higher levels in the mutants than in WT under both normal and cold conditions, suggesting the mutants are partially impaired in pre-rRNA processing. Taken together, the results suggest that AtRH7 affects rRNA biogenesis and plays an important role in plant growth under cold.

  19. The progeny of Arabidopsis thaliana plants exposed to salt exhibit changes in DNA methylation, histone modifications and gene expression.

    Directory of Open Access Journals (Sweden)

    Andriy Bilichak

    Full Text Available Plants are able to acclimate to new growth conditions on a relatively short time-scale. Recently, we showed that the progeny of plants exposed to various abiotic stresses exhibited changes in genome stability, methylation patterns and stress tolerance. Here, we performed a more detailed analysis of methylation patterns in the progeny of Arabidopsis thaliana (Arabidopsis plants exposed to 25 and 75 mM sodium chloride. We found that the majority of gene promoters exhibiting changes in methylation were hypermethylated, and this group was overrepresented by regulators of the chromatin structure. The analysis of DNA methylation at gene bodies showed that hypermethylation in the progeny of stressed plants was primarily due to changes in the 5' and 3' ends as well as in exons rather than introns. All but one hypermethylated gene tested had lower gene expression. The analysis of histone modifications in the promoters and coding sequences showed that hypermethylation and lower gene expression correlated with the enrichment of H3K9me2 and depletion of H3K9ac histones. Thus, our work demonstrated a high degree of correlation between changes in DNA methylation, histone modifications and gene expression in the progeny of salt-stressed plants.

  20. FYVE zinc-finger proteins in the plant model Arabidopsis thaliana

    DEFF Research Database (Denmark)

    Jensen, R B; La Cour, T; Albrethsen, J

    2001-01-01

    , named PRAF, consist of a pleckstrin homology (PH) domain, a regulator of chromosome condensation (RCC1) guanine nucleotide exchange factor repeat domain, and a variant FYVE domain containing an Asn residue and a Tyr residue at positions corresponding to the PtdIns3P-interacting His(4) and Arg(6......Classic FYVE zinc-finger domains recognize the phosphoinositide signal PtdIns3P and share the basic (R/K)(1)(R/K)HHCR(6) (single-letter amino acid codes) consensus sequence. This domain is present in predicted PtdIns3P 5-kinases and lipases from Arabidopsis thaliana. Other Arabidopsis proteins......) of the basic motif. Dot-blot and liposome-binding assays were used in vitro to examine the phospholipid-binding ability of isolated PRAF domains. Whereas the PH domain preferentially bound PtdIns(4,5)P(2), the variant FYVE domain showed a weaker charge-dependent binding of phosphoinositides. In contrast...

  1. Use of the "gl1" Mutant and the "CA-rop2" Transgenic Plants of "Arabidopsis thaliana" in the Biology Laboratory Course

    Science.gov (United States)

    Zheng, Zhi-Liang

    2006-01-01

    This article describes the use of the "glabrous1 (g11)" mutant and constitutively active "(CA)-rop2" transgenic plants of "Arabidopsis thaliana" in teaching genetics laboratory for both high school and undergraduate students. The experiments provide students with F[subscript 1] and F[subscript 2] generations within a semester for genetic and…

  2. Modulation of ethylene- and heat-controlled hyponastic leaf movement in Arabidopsis thaliana by the plant defence hormones jasmonate and salicylate

    NARCIS (Netherlands)

    Zanten, M. van; Ritsema, T.; Polko, J.K.; Leon-Reyes, A.; Voesenek, L.A.C.J.; Millenaar, F.F.; Pieterse, C.M.J.; Peeters, A.J.M.

    2012-01-01

    Upward leaf movement (hyponastic growth) is adopted by several plant species including Arabidopsis thaliana, as a mechanism to escape adverse growth conditions. Among the signals that trigger hyponastic growth are, the gaseous hormone ethylene, low light intensities, and supra-optimal temperatures (

  3. VOZ; isolation and characterization of novel vascular plant transcription factors with a one-zinc finger from Arabidopsis thaliana.

    Science.gov (United States)

    Mitsuda, Nobutaka; Hisabori, Toru; Takeyasu, Kunio; Sato, Masa H

    2004-07-01

    A 38-bp pollen-specific cis-acting region of the AVP1 gene is involved in the expression of the Arabidopsis thaliana V-PPase during pollen development. Here, we report the isolation and structural characterization of AtVOZ1 and AtVOZ2, novel transcription factors that bind to the 38-bp cis-acting region of A. thaliana V-PPase gene, AVP1. AtVOZ1 and AtVOZ2 show 53% amino acid sequence similarity. Homologs of AtVOZ1 and AtVOZ2 are found in various vascular plants as well as a moss, Physcomitrella patens. Promoter-beta-glucuronidase reporter analysis shows that AtVOZ1 is specifically expressed in the phloem tissue and AtVOZ2 is strongly expressed in the root. In vivo transient effector-reporter analysis in A. thaliana suspension-cultured cells demonstrates that AtVOZ1 and AtVOZ2 function as transcriptional activators in the Arabidopsis cell. Two conserved regions termed Domain-A and Domain-B were identified from an alignment of AtVOZ proteins and their homologs of O. sativa and P. patens. AtVOZ2 binds as a dimer to the specific palindromic sequence, GCGTNx7ACGC, with Domain-B, which is comprised of a functional novel zinc coordinating motif and a conserved basic region. Domain-B is shown to function as both the DNA-binding and the dimerization domains of AtVOZ2. From highly the conservative nature among all identified VOZ proteins, we conclude that Domain-B is responsible for the DNA binding and dimerization of all VOZ-family proteins and designate it as the VOZ-domain.

  4. Melatonin in Arabidopsis thaliana acts as plant growth regulator at low concentrations and preserves seed viability at high concentrations.

    Science.gov (United States)

    Hernández, Ismaél Gatica; Gomez, Federico José Vicente; Cerutti, Soledad; Arana, María Verónica; Silva, María Fernanda

    2015-09-01

    Since the discovery of melatonin in plants, several roles have been described for different species, organs, and developmental stages. Arabidopsis thaliana, being a model plant species, is adequate to contribute to the elucidation of the role of melatonin in plants. In this work, melatonin was monitored daily by UHPLC-MS/MS in leaves, in order to study its diurnal accumulation as well as the effects of natural and artificial light treatments on its concentration. Furthermore, the effects of exogenous application of melatonin to assess its role in seed viability after heat stress and as a regulator of growth and development of vegetative tissues were evaluated. Our results indicate that melatonin contents in Arabidopsis were higher in plants growing under natural radiation when compared to those growing under artificial conditions, and its levels were not diurnally-regulated. Exogenous melatonin applications prolonged seed viability after heat stress conditions. In addition, melatonin applications retarded leaf senescence. Its effects as growth promoter were dose and tissue-dependent; stimulating root growth at low concentrations and decreasing leaf area at high doses.

  5. Effects of salt stress on wild type and vte4 mutant Arabidopsis thaliana: Model plant to engineer tolerance towards salinity

    Directory of Open Access Journals (Sweden)

    Khalatbari Amir Ali

    2013-01-01

    Full Text Available One of the major environmental constraints impairing plant distribution and yield is believed to be salt stress. Additionally, engineered abiotic stress resistance or/and tolerance is considered as an indispensable target in order to enhance plant productivity. In this study, the effects of salinity on physiological and morphological of wild type (Columbia-0 and vte4 mutant Arabidopsis thaliana were investigated under different NaCl concentrations. These salt treatments, including control condition, 50mM and 100mM NaCl were imposed on the plants. Each salt treatment was replicated three times in a complete randomized design with factorial arrangement. Wild type and mutant A.thaliana plants were subjected to the abiotic stress (salinity for up to 11 days to evaluate the parameters of growth, development and water relations. As a result, the performance of wild type plants was stronger than vte4 mutant under different salt treatments. Under control condition, rosette dry weight, maximum quantum efficiency (PSII and specific leaf area obtained the highest values of 13.85 mg, considered, wild type A.thaliana recorded higher value of 0.82 gW/gFW for relative water content (RWC under 50mM NaCl whereas mutant plants gained the value of 0.78 gW/gFW under the same condition. However, root mass fraction indicated an increase for both wild type and vte4 mutant plants after 11 days of salt stress onset. The reduction of water potential was observed for wild type and mutant A.thaliana where it scored -1.3 MPa and -1.4, respectively. As a conclusion, these findings implied that under different salt treatments morphological and physiological responses of wild type and vte4 mutant were affected in which wild type plants showed more tolerance. Lack of γ-tocopherol methyltransferase (γ -TMT gene in vte4 seemed to impair defence mechanism of this mutant against salinity.

  6. A general G1/S-phase cell-cycle control module in the flowering plant Arabidopsis thaliana.

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    Xin'Ai Zhao

    Full Text Available The decision to replicate its DNA is of crucial importance for every cell and, in many organisms, is decisive for the progression through the entire cell cycle. A comparison of animals versus yeast has shown that, although most of the involved cell-cycle regulators are divergent in both clades, they fulfill a similar role and the overall network topology of G1/S regulation is highly conserved. Using germline development as a model system, we identified a regulatory cascade controlling entry into S phase in the flowering plant Arabidopsis thaliana, which, as a member of the Plantae supergroup, is phylogenetically only distantly related to Opisthokonts such as yeast and animals. This module comprises the Arabidopsis homologs of the animal transcription factor E2F, the plant homolog of the animal transcriptional repressor Retinoblastoma (Rb-related 1 (RBR1, the plant-specific F-box protein F-BOX-LIKE 17 (FBL17, the plant specific cyclin-dependent kinase (CDK inhibitors KRPs, as well as CDKA;1, the plant homolog of the yeast and animal Cdc2⁺/Cdk1 kinases. Our data show that the principle of a double negative wiring of Rb proteins is highly conserved, likely representing a universal mechanism in eukaryotic cell-cycle control. However, this negative feedback of Rb proteins is differently implemented in plants as it is brought about through a quadruple negative regulation centered around the F-box protein FBL17 that mediates the degradation of CDK inhibitors but is itself directly repressed by Rb. Biomathematical simulations and subsequent experimental confirmation of computational predictions revealed that this regulatory circuit can give rise to hysteresis highlighting the here identified dosage sensitivity of CDK inhibitors in this network.

  7. An epifluorescent attachment improves whole-plant digital photography of Arabidopsis thaliana expressing red-shifted green fluorescent protein

    Science.gov (United States)

    Baker, Stokes S.; Vidican, Cleo B.; Cameron, David S.; Greib, Haittam G.; Jarocki, Christine C.; Setaputri, Andres W.; Spicuzza, Christopher H.; Burr, Aaron A.; Waqas, Meriam A.; Tolbert, Danzell A.

    2012-01-01

    Background and aims Studies have shown that levels of green fluorescent protein (GFP) leaf surface fluorescence are directly proportional to GFP soluble protein concentration in transgenic plants. However, instruments that measure GFP surface fluorescence are expensive. The goal of this investigation was to develop techniques with consumer digital cameras to analyse GFP surface fluorescence in transgenic plants. Methodology Inexpensive filter cubes containing machine vision dichroic filters and illuminated with blue light-emitting diodes (LED) were designed to attach to digital single-lens reflex (SLR) camera macro lenses. The apparatus was tested on purified enhanced GFP, and on wild-type and GFP-expressing arabidopsis grown autotrophically and heterotrophically. Principal findings Spectrum analysis showed that the apparatus illuminates specimens with wavelengths between ∼450 and ∼500 nm, and detects fluorescence between ∼510 and ∼595 nm. Epifluorescent photographs taken with SLR digital cameras were able to detect red-shifted GFP fluorescence in Arabidopsis thaliana leaves and cotyledons of pot-grown plants, as well as roots, hypocotyls and cotyledons of etiolated and light-grown plants grown heterotrophically. Green fluorescent protein fluorescence was detected primarily in the green channel of the raw image files. Studies with purified GFP produced linear responses to both protein surface density and exposure time (H0: β (slope) = 0 mean counts per pixel (ng s mm−2)−1, r2 > 0.994, n = 31, P < 1.75 × 10−29). Conclusions Epifluorescent digital photographs taken with complementary metal-oxide-semiconductor and charge-coupled device SLR cameras can be used to analyse red-shifted GFP surface fluorescence using visible blue light. This detection device can be constructed with inexpensive commercially available materials, thus increasing the accessibility of whole-organism GFP expression analysis to research laboratories and teaching institutions with

  8. Protocol: optimising hydroponic growth systems for nutritional and physiological analysis of Arabidopsis thaliana and other plants

    Science.gov (United States)

    2013-01-01

    Background Hydroponic growth systems are a convenient platform for studying whole plant physiology. However, we found through trialling systems as they are described in the literature that our experiments were frequently confounded by factors that affected plant growth, including algal contamination and hypoxia. We also found the way in which the plants were grown made them poorly amenable to a number of common physiological assays. Results The drivers for the development of this hydroponic system were: 1) the exclusion of light from the growth solution; 2) to simplify the handling of individual plants, and 3) the growth of the plant to allow easy implementation of multiple assays. These aims were all met by the use of pierced lids of black microcentrifuge tubes. Seed was germinated on a lid filled with an agar-containing germination media immersed in the same solution. Following germination, the liquid growth media was exchanged with the experimental solution, and after 14-21 days seedlings were transferred to larger tanks with aerated solution where they remained until experimentation. We provide details of the protocol including composition of the basal growth solution, and separate solutions with altered calcium, magnesium, potassium or sodium supply whilst maintaining the activity of the majority of other ions. We demonstrate the adaptability of this system for: gas exchange measurement on single leaves and whole plants; qRT-PCR to probe the transcriptional response of roots or shoots to altered nutrient composition in the growth solution (we demonstrate this using high and low calcium supply); producing highly competent mesophyll protoplasts; and, accelerating the screening of Arabidopsis transformants. This system is also ideal for manipulating plants for micropipette techniques such as electrophysiology or SiCSA. Conclusions We present an optimised plant hydroponic culture system that can be quickly and cheaply constructed, and produces plants with similar

  9. Testing models for the leaf economics spectrum with leaf and whole-plant traits in Arabidopsis thaliana.

    Science.gov (United States)

    Blonder, Benjamin; Vasseur, François; Violle, Cyrille; Shipley, Bill; Enquist, Brian J; Vile, Denis

    2015-05-08

    The leaf economics spectrum (LES) describes strong relationships between multiple functional leaf traits that determine resource fluxes in vascular plants. Five models have been proposed to explain these patterns: two based on patterns of structural allocation, two on venation networks and one on resource allocation to cell walls and cell contents. Here we test these models using data for leaf and whole-plant functional traits. We use structural equation modelling applied to multiple ecotypes, recombinant inbred lines, near isogenic lines and vascular patterning mutants of Arabidopsis thaliana that express LES trait variation. We show that a wide variation in multiple functional traits recapitulates the LES at the whole-plant scale. The Wright et al. (2004) model and the Blonder et al. (2013) venation network model cannot be rejected by data, while two simple models and the Shipley et al. (2006) allocation model are rejected. Venation networks remain a key hypothesis for the origin of the LES, but simpler explanations also cannot be ruled out.

  10. Oxidative stress responses induced by uranium exposure at low pH in leaves of Arabidopsis thaliana plants.

    Science.gov (United States)

    Saenen, Eline; Horemans, Nele; Vanhoudt, Nathalie; Vandenhove, Hildegarde; Biermans, Geert; van Hees, May; Wannijn, Jean; Vangronsveld, Jaco; Cuypers, Ann

    2015-12-01

    Anthropogenic activities have led to a widespread uranium (U) contamination in many countries. The toxic effects of U at the cellular level have mainly been investigated at a pH around 5.5, the optimal pH for hydroponically grown plants. However, since the speciation of U, and hence its toxicity, is strongly dependent on environmental factors such as the pH, it is important to investigate the effects of U at different environmentally relevant pH levels. Although U is poorly translocated from the roots to the shoots, resulting in a low U concentration in the leaves, it has been demonstrated that toxic effects in the leaves were already visible after 1 day exposure at pH 5.5, although only when exposed to relatively high U concentrations (100 μM). Therefore, the present study aimed to analyse the effects of different U concentrations (ranging from 0 to 100 μM) at pH 4.5 in leaves of Arabidopsis thaliana plants. Results indicate that U induces early senescence in A. thaliana leaves as was suggested by a decreased expression of CAT2 accompanied by an induction of CAT3 expression, a decreased CAT capacity and an increased lipid peroxidation. In addition, miRNA398b/c is involved in the regulation of the SOD response in the leaves. As such, an increased MIR398b/c expression was observed leading to a decreased transcript level of CSD1/2. Finally, the biosynthesis of ascorbate was induced after U exposure. This can point towards an important role for this metabolite in the scavenging of reactive oxygen species under U stress.

  11. A comparison of the low temperature transcriptomes and CBF regulons of three plant species that differ in freezing tolerance: Solanum commersonii, Solanum tuberosum, and Arabidopsis thaliana

    OpenAIRE

    Carvallo, Marcela A.; Pino, María-Teresa; Jeknić, Zoran; Zou, Cheng; Doherty, Colleen J.; Shiu, Shin-Han; Chen, Tony H. H.; Thomashow, Michael F.

    2011-01-01

    Solanum commersonii and Solanum tuberosum are closely related plant species that differ in their abilities to cold acclimate; whereas S. commersonii increases in freezing tolerance in response to low temperature, S. tuberosum does not. In Arabidopsis thaliana, cold-regulated genes have been shown to contribute to freezing tolerance, including those that comprise the CBF regulon, genes that are controlled by the CBF transcription factors. The low temperature transcriptomes and CBF regulons of ...

  12. Cytogenetic tools for Arabidopsis thaliana

    NARCIS (Netherlands)

    Koornneef, M.; Fransz, P.F.; Jong, de J.H.S.G.M.

    2003-01-01

    Although the first description of chromosomes of Arabidopsis dates as far back as 1907, little attention was paid to its cytogenetics for a long time. The spectacular interest in chromosome research for this species that now is the model plant species by excellence came with the introduction of mole

  13. Sequence and RT-PCR expression analysis of two peroxidases from Arabidopsis thaliana belonging to a novel evolutionary branch of plant perioxidases

    DEFF Research Database (Denmark)

    Kjærsgård, I.V.H.; Jespersen, H.M.; Rasmussen, Søren Kjærsgård;

    1997-01-01

    cDNA clones encoding two new Arabidopsis thaliana peroxidases, ATP la and ATP 2a, have been identified by searching the Arabidopsis database of expressed sequence tags (dbEST). They represent a novel branch of hitherto uncharacterized plant peroxidases which is only 35% identical in amino acid...... of unknown function, is likely to be widespread in plant species. The atp 1 and atp 2 types of cDNA sequences were the most redundant among the 28 different isoperoxidases identified among about 200 peroxidase encoding ESTs. Interestingly, 8 out of totally 38 EST sequences coding for ATP 1 showed three...... sequence to the well characterized group of basic plant peroxidases represented by the horseradish (Armoracia rusticana) isoperoxidases HRP C, HRP E5 and the similar Arabidopsis isoperoxidases ATP Ca, ATP Cb, and ATP Ea. However ATP 1a is 87% identical in amino acid sequence to a peroxidase encoded by an m...

  14. Proteomic Responses in Arabidopsis thaliana Seedlings Treated with Ethylene

    Science.gov (United States)

    Ethylene (ET) is a volatile plant growth hormone that most famously modulates fruit ripening, but it also controls plant growth, development and stress responses. In Arabidopsis thaliana, ET is perceived by receptors in the endoplasmic reticulum, and a signal is transduced through a protein kinase,...

  15. Accumulation of coumarins in Arabidopsis thaliana.

    Science.gov (United States)

    Kai, Kosuke; Shimizu, Bun-ichi; Mizutani, Masaharu; Watanabe, Ken; Sakata, Kanzo

    2006-02-01

    The biosynthesis of coumarins in plants is not well understood, although these metabolic pathways are often found in the plant kingdom. We report here the occurrence of coumarins in Arabidopsis thaliana ecotype Columbia. Considerably high levels of scopoletin and its beta-d-glucopyranoside, scopolin, were found in the wild-type roots. The scopolin level in the roots was approximately 1200nmol/gFW, which was approximately 180-fold of that in the aerial parts. Calli accumulated scopolin at a level of 70nmol/gFW. Scopoletin and scopolin formation were induced in shoots after treatment with either 2,4-dichlorophenoxyacetic acid (at 100microM) or a bud-cell suspension of Fusarium oxysporum. In order to gain insight into the biosynthetic pathway of coumarins in A. thaliana, we analyzed coumarins in the mutants obtained from the SALK Institute collection that carried a T-DNA insertion within the gene encoding the cytochrome P450, CYP98A3, which catalyzes 3'-hydroxylation of p-coumarate units in the phenylpropanoid pathway. The content of scopoletin and scopolin in the mutant roots greatly decreased to approximately 3% of that in the wild-type roots. This observation suggests that scopoletin and scopolin biosynthesis in A. thaliana are strongly dependent on the 3'-hydroxylation of p-coumarate units catalyzed by CYP98A3. We also found that the level of skimmin, a beta-d-glucopyranoside of umbelliferone, was slightly increased in the mutant roots.

  16. Defining the core Arabidopsis thaliana root microbiome

    Science.gov (United States)

    Gehring, Jase; Malfatti, Stephanie; Tremblay, Julien; Engelbrektson, Anna; Kunin, Victor; del Rio, Tijana Glavina; Edgar, Robert C.; Eickhorst, Thilo; Ley, Ruth E.; Hugenholtz, Philip; Tringe, Susannah Green; Dangl, Jeffery L.

    2014-01-01

    Land plants associate with a root microbiota distinct from the complex microbial community present in surrounding soil. The microbiota colonizing therhizosphere(immediately surroundingthe root) and the endophytic compartment (within the root) contribute to plant growth, productivity, carbon sequestration and phytoremediation1-3. Colonization of the root occurs despite a sophisticated plant immune system4,5, suggesting finely tuned discrimination of mutualists and commensals from pathogens. Genetic principles governing the derivation of host-specific endophyte communities from soil communities are poorly understood. Here we report the pyrosequencing of the bacterial 16S ribosomal RNA gene of more than 600 Arabidopsis thaliana plants to test the hypotheses that the root rhizosphere and endophytic compartment microbiota of plants grown under controlled conditions in natural soils are sufficiently dependent on the host to remain consistent across different soil types and developmental stages, and sufficiently dependent on host genotype to vary between inbred Arabidopsis accessions. We describe different bacterial communities in two geochemically distinct bulk soils and in rhizosphere and endophytic compartments prepared from roots grown in these soils. The communities in each compartment are strongly influenced by soil type. Endophytic compartments from both soils feature overlapping, low-complexity communities that are markedly enriched in Actinobacteria and specific families from other phyla, notably Proteobacteria. Some bacteria vary quantitatively between plants of different developmental stage and genotype. Our rigorous definition of an endophytic compartment microbiome should facilitate controlled dissection of plantmicrobe interactions derived from complex soil communities. PMID:22859206

  17. A Generalist Herbivore Copes with Specialized Plant Defence: the Effects of Induction and Feeding by Helicoverpa armigera (Lepidoptera: Noctuidae) Larvae on Intact Arabidopsis thaliana (Brassicales) Plants.

    Science.gov (United States)

    Zalucki, M P; Zalucki, J M; Perkins, L E; Schramm, K; Vassão, D G; Gershenzon, J; Heckel, D G

    2017-06-01

    Plants of the Brassicaceae are defended from feeding by generalist insects by constitutively-expressed and herbivory-induced glucosinolates (GS). We induced Arabidopsis plants 1, 16 and 24 h prior to allowing neonate larvae of the generalist Helicoverpa armigera to feed on whole plants for 72 h. These plants were subsequently retested with another group of neonates for a further 72 h. We used wild-type A. thaliana Col-0, and mutant lines lacking indolic GS, aliphatic GS or all GS. We hypothesized that larvae would not grow well on defended plants (WT) compared to those lacking GS, and would not grow well if plants had been primed or fed on for longer, due to the expected induced GS. There was survivorship on all lines suggesting H. armigera is a suitable generalist for these experiments. Larvae performed less well on wild-type and no indolic lines than on no aliphatic and no GS lines. Larvae distributed feeding damage extensively in all lines, more so on wild type and no-indolic lines. Contrary to expectations, larvae grew better on plants that had been induced for 1 to 16 h than on un-induced plants suggesting they moved to and selected less toxic plant parts within a heterogeneously defended plant. Performance declined on all lines if plants had been induced for 24 h, or had been fed upon for a further 72 h. However, contrary to expectation, individual and total GS did not increase after these two treatments. This suggests that Arabidopsis plants induce additional (not GS) defenses after longer induction periods.

  18. Characterization Of Laccase T-DNA Mutants In Arabidopsis thaliana

    DEFF Research Database (Denmark)

    Andersen, Jeppe R; Asp, Torben; Mansfield, Shawn

    Laccases (P-diphenol:O2 oxidoreductase; EC 1.10.3.2), also termed laccase-like multicopper oxidases, are blue copper-containing oxidases which comprise multigene families in plants. In the Arabidopsis thaliana genome, 17 laccase genes (LAC1 to LAC17) have been annotated. To identify laccases invo...... different and distinct biochemical pathways and that laccases might be involved in polymerization of both polysaccharides and monolignols in the Arabidopsis cell wall....

  19. Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) determination of phase II metabolites of the mycotoxin zearalenone in the model plant Arabidopsis thaliana

    Science.gov (United States)

    BERTHILLER, F.; WERNER, U.; SULYOK, M.; KRSKA, R.; HAUSER, M.-T.; SCHUHMACHER, R.

    2010-01-01

    The biotransformation products of zearalenone, a Fusarium mycotoxin, were elucidated using the model plant Arabidopsis thaliana. After treatment of plant seedlings with 50 μM zearalenone, both the liquid media and the plant extracts were analysed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). An array of 17 different metabolites, most prominently glucosides, malonylglucosides, di-hexose- and hexose–pentose disaccharides of zearalenone, and α- and β-zearalenol, were detected in the samples. Time courses for the different zearalenone metabolites were recorded and they give a closer insight into the metabolism kinetics. A scheme proposing the zearalenone metabolism in A. thaliana is given. The aspect of food safety regarding the (potential) occurrence of masked mycotoxins in agricultural commodities is discussed. PMID:17071522

  20. Arabidopsis thaliana VOZ (Vascular plant One-Zinc finger) transcription factors are required for proper regulation of flowering time.

    Science.gov (United States)

    Celesnik, Helena; Ali, Gul S; Robison, Faith M; Reddy, Anireddy S N

    2013-04-15

    Transition to flowering in plants is tightly controlled by environmental cues, which regulate the photoperiod and vernalization pathways, and endogenous signals, which mediate the autonomous and gibberellin pathways. In this work, we investigated the role of two Zn(2+)-finger transcription factors, the paralogues AtVOZ1 and AtVOZ2, in Arabidopsis thaliana flowering. Single atvoz1-1 and atvoz2-1 mutants showed no significant phenotypes as compared to wild type. However, atvoz1-1 atvoz2-1 double mutant plants exhibited several phenotypes characteristic of flowering-time mutants. The double mutant displayed a severe delay in flowering, together with additional pleiotropic phenotypes. Late flowering correlated with elevated expression of FLOWERING LOCUS C (FLC), which encodes a potent floral repressor, and decreased expression of its target, the floral promoter FD. Vernalization rescued delayed flowering of atvoz1-1 atvoz2-1 and reversed elevated FLC levels. Accumulation of FLC transcripts in atvoz1-1 atvoz2-1 correlated with increased expression of several FLC activators, including components of the PAF1 and SWR1 chromatin-modifying complexes. Additionally, AtVOZs were shown to bind the promoter of MOS3/SAR3 and directly regulate expression of this nuclear pore protein, which is known to participate in the regulation of flowering time, suggesting that AtVOZs exert at least some of their flowering regulation by influencing the nuclear pore function. Complementation of atvoz1-1 atvoz2-1 with AtVOZ2 reversed all double mutant phenotypes, confirming that the observed morphological and molecular changes arise from the absence of functional AtVOZ proteins, and validating the functional redundancy between AtVOZ1 and AtVOZ2.

  1. Characterization Of Laccase T-DNA Mutants In Arabidopsis thaliana

    DEFF Research Database (Denmark)

    Andersen, Jeppe R; Asp, Torben; Mansfield, Shawn

    Laccases (P-diphenol:O2 oxidoreductase; EC 1.10.3.2), also termed laccase-like multicopper oxidases, are blue copper-containing oxidases which comprise multigene families in plants. In the Arabidopsis thaliana genome, 17 laccase genes (LAC1 to LAC17) have been annotated. To identify laccases...

  2. Neutralization of Bacterial YoeBSpn Toxicity and Enhanced Plant Growth in Arabidopsis thaliana via Co-Expression of the Toxin-Antitoxin Genes

    Directory of Open Access Journals (Sweden)

    Fauziah Abu Bakar

    2016-04-01

    Full Text Available Bacterial toxin-antitoxin (TA systems have various cellular functions, including as part of the general stress response. The genome of the Gram-positive human pathogen Streptococcus pneumoniae harbors several putative TA systems, including yefM-yoeBSpn, which is one of four systems that had been demonstrated to be biologically functional. Overexpression of the yoeBSpn toxin gene resulted in cell stasis and eventually cell death in its native host, as well as in Escherichia coli. Our previous work showed that induced expression of a yoeBSpn toxin-Green Fluorescent Protein (GFP fusion gene apparently triggered apoptosis and was lethal in the model plant, Arabidopsis thaliana. In this study, we investigated the effects of co-expression of the yefMSpn antitoxin and yoeBSpn toxin-GFP fusion in transgenic A. thaliana. When co-expressed in Arabidopsis, the YefMSpn antitoxin was found to neutralize the toxicity of YoeBSpn-GFP. Interestingly, the inducible expression of both yefMSpn antitoxin and yoeBSpn toxin-GFP fusion in transgenic hybrid Arabidopsis resulted in larger rosette leaves and taller plants with a higher number of inflorescence stems and increased silique production. To our knowledge, this is the first demonstration of a prokaryotic antitoxin neutralizing its cognate toxin in plant cells.

  3. SUPPRESSOR OF APICAL DOMINANCE1 of Sporisorium reilianum changes inflorescence branching at early stages in di- and monocot plants and induces fruit abortion in Arabidopsis thaliana.

    Science.gov (United States)

    Drechsler, Frank; Schwinges, Patrick; Schirawski, Jan

    2016-05-03

    sporisorium reilianum f. sp. zeae is a biotrophic smut fungus that infects maize (Zea mays). Among others, the fungus-plant interaction is governed by secreted fungal effector proteins. The effector SUPPRESSOR OF APICAL DOMINANCE1 (SAD1) changes the development of female inflorescences and induces outgrowth of subapical ears in S. reilianum-infected maize. When stably expressed in Arabidopsis thaliana as a GFP-SAD1 fusion protein, SAD1 induces earlier inflorescence branching and abortion of siliques. Absence of typical hormone-dependent phenotypes in other parts of the transgenic A. thaliana plants expressing GFP-SAD1 hint to a hormone-independent induction of bud outgrowth by SAD1. Silique abortion and bud outgrowth are also known to be controlled by carbon source concentration and by stress-induced molecules, making these factors interesting potential SAD1 targets.

  4. Plasmodesmata in Arabidopsis thaliana suspension cells.

    Science.gov (United States)

    Bayer, E; Thomas, C L; Maule, A J

    2004-06-01

    A current challenge in plant biology is to identify the structural and functional components of plasmodesmata (PDs). The use of plant tissue as a source material for plasmodesmal characterisation has had limited success, so we have explored the frequency and features of PDs occurring in suspension cell cultures of Arabidopsis thaliana. This material has the advantages of homogeneity, quantity, and ease of disruption. Using light and electron microscopy and immunostaining for callose and calreticulin, we showed that suspension cells laid down abundant PDs in division walls, and that vestiges of these structures were retained as half PDs even when the cell-to-cell contacts were disrupted during culture growth. Although callose was a reliable marker for PD distribution, which was deposited in an organised collar around the neck of PDs, it was not abundant in unstressed cells. Calreticulin and the chemical stain 3,3'-dihexyloxacarbocyanine iodide also provided useful markers when monitoring PDs in cell wall preparations by light microscopy. Purified cell walls were shown to be virtually free of contamination from cytoplasmic components, except for the presence of small amounts of cortical endoplasmic reticulum attached to PDs. Hence, clean cell walls from A. thaliana suspension cells provide a valuable resource for a proteomic approach to the analysis of plasmodesmal components.

  5. New Arabidopsis thaliana cytochrome c partners: a look into the elusive role of cytochrome c in programmed cell death in plants.

    Science.gov (United States)

    Martínez-Fábregas, Jonathan; Díaz-Moreno, Irene; González-Arzola, Katiuska; Janocha, Simon; Navarro, José A; Hervás, Manuel; Bernhardt, Rita; Díaz-Quintana, Antonio; De la Rosa, Miguel Á

    2013-12-01

    Programmed cell death is an event displayed by many different organisms along the evolutionary scale. In plants, programmed cell death is necessary for development and the hypersensitive response to stress or pathogenic infection. A common feature in programmed cell death across organisms is the translocation of cytochrome c from mitochondria to the cytosol. To better understand the role of cytochrome c in the onset of programmed cell death in plants, a proteomic approach was developed based on affinity chromatography and using Arabidopsis thaliana cytochrome c as bait. Using this approach, ten putative new cytochrome c partners were identified. Of these putative partners and as indicated by bimolecular fluorescence complementation, nine of them bind the heme protein in plant protoplasts and human cells as a heterologous system. The in vitro interaction between cytochrome c and such soluble cytochrome c-targets was further corroborated using surface plasmon resonance. Taken together, the results obtained in the study indicate that Arabidopsis thaliana cytochrome c interacts with several distinct proteins involved in protein folding, translational regulation, cell death, oxidative stress, DNA damage, energetic metabolism, and mRNA metabolism. Interestingly, some of these novel Arabidopsis thaliana cytochrome c-targets are closely related to those for Homo sapiens cytochrome c (Martínez-Fábregas et al., unpublished). These results indicate that the evolutionarily well-conserved cytosolic cytochrome c, appearing in organisms from plants to mammals, interacts with a wide range of targets on programmed cell death. The data have been deposited to the ProteomeXchange with identifier PXD000280.

  6. Arabidopsis thaliana PECP1: enzymatic characterization and structural organization of the first plant phosphoethanolamine/phosphocholine phosphatase.

    Science.gov (United States)

    May, Anett; Spinka, Michael; Köck, Margret

    2012-02-01

    Maintenance of cellular phosphate homeostasis is crucial for primary and energy metabolism. In plants, low exogenous phosphate availability activates adaptive responses that include the immediate liberation of Pi from phosphorylated metabolites by yet uncharacterized intracellular phosphatases. Based on transcriptional analyses, the Arabidopsis thaliana gene At1g17710, a member of the HAD (Haloacid Dehalogenase) superfamily, was one of the most promising candidates. Here, we show by recombinant protein production and analysis of purified protein that the gene At1g17710 encodes a phosphoethanolamine/phosphocholine phosphatase (EC 3.1.3.75). Thus, the gene product was termed AtPECP1. The present study demonstrates that the Mg(2+)-dependent enzyme exhibits pronounced specificity for both substrates. The enzyme displays a broad pH optimum ranging from pH 6 to pH 8. Comparison of K(m) values indicates a slightly higher affinity for phosphocholine (0.44 mM) than for phosphoethanolamine (1.16 mM). The catalytic efficiency, however, is markedly higher for phosphoethanolamine than for phosphocholine being 1.06 × 10(4)M(-1)s(-1) and 2.34 × 10(3)M(-1)s(-1), respectively. Size exclusion chromatography, native gel electrophoresis and SAXS experiments with recombinant protein clearly point to a rapid monomer-dimer equilibrium of protein subunits. Given its established substrate specificity the enzyme is likely to be involved in the liberation of inorganic phosphate from intracellular sources and is especially in demand under phosphate-deprived conditions. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Identification of Polyadenylation Sites within Arabidopsis Thaliana

    KAUST Repository

    Kalkatawi, Manal

    2011-09-01

    Machine Learning (ML) is a field of artificial intelligence focused on the design and implementation of algorithms that enable creation of models for clustering, classification, prediction, ranking and similar inference tasks based on information contained in data. Many ML algorithms have been successfully utilized in a variety of applications. The problem addressed in this thesis is from the field of bioinformatics and deals with the recognition of polyadenylation (poly(A)) sites in the genomic sequence of the plant Arabidopsis thaliana. During the RNA processing, a tail consisting of a number of consecutive adenine (A) nucleotides is added to the terminal nucleotide of the 3’- untranslated region (3’UTR) of the primary RNA. The process in which these A nucleotides are added is called polyadenylation. The location in the genomic DNA sequence that corresponds to the start of terminal A nucleotides (i.e. to the end of 3’UTR) is known as a poly(A) site. Recognition of the poly(A) sites in DNA sequence is important for better gene annotation and understanding of gene regulation. In this study, we built an artificial neural network (ANN) for the recognition of poly(A) sites in the Arabidopsis thaliana genome. Our study demonstrates that this model achieves improved accuracy compared to the existing predictive models for this purpose. The key factor contributing to the enhanced predictive performance of our ANN model is a distinguishing set of features used in creation of the model. These features include a number of physico-chemical characteristics of relevance, such as dinucleotide thermodynamic characteristics, electron-ion interaction potential, etc., but also many of the statistical properties of the DNA sequences from the region surrounding poly(A) site, such as nucleotide and polynucleotide properties, common motifs, etc. Our ANN model was compared in performance with several other ML models, as well as with the PAC tool that is specifically developed for

  8. Transfer RNA modifications and genes for modifying enzymes in Arabidopsis thaliana

    National Research Council Canada - National Science Library

    Chen, Peng; Jäger, Gunilla; Zheng, Bo

    2010-01-01

    .... The purpose of this study was to identify genes involved in tRNA modification in the model plant Arabidopsis thaliana, to understand the function of nucleoside modifications in plant growth and development...

  9. Molecular analysis of plant architecture in Arabidopsis thaliana using activation tagging.

    NARCIS (Netherlands)

    Chalfun Junior, A.

    2004-01-01

    Keywords: Arabidopsisthaliana, activation tagging, T-DNA, transposon, mutants, enhancer, DNA methylation, plant architecture, development, forward/reverse genetics, lateral organs, flower, vascular tissue, HLH, transmembrane, transcription factorsPlant development is one of the mos

  10. Cloning the Promoter of BcNA1 from Brassica napus and Fad2 Gene from Arabidopsis thaliana and Construction of the Plant Expression Vector

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The upstream regulatory region of a seed-specific gene was isolated from the genomic DNA of Brassica napus by PCR amplification. The cloned fragment contained 1755 nucleotides, and shared a sequence homology of 99.6% with the reported data. The coding region of oleic acid desaturase gene was then cloned from Arabidopsis thaliana. The sequencing analysis indicated that the sequence of the PCR product was just the same as reported before. In addition, the plant expression vector harboring the seed-specific promoter and trans-Fad2 gene was constructed.

  11. A role for arabinogalactan-proteins in plant cell expansion: evidence from studies on the interaction of ß-glucosyl Yariv reagent with seedlings of Arabidopsis thaliana

    DEFF Research Database (Denmark)

    Willats, William George Tycho; Knox, J.P.

    1996-01-01

    Seedlings of Arabidopsis thaliana were germinated and grown in medium containing ß-glucosyl Yariv reagent (ßGlcY), a synthetic phenyl glycoside that interacts specifically with arabinogalactan-proteins (AGPs), a class of plant cell surface proteoglycans. The effect of ßGlcY on the seedlings...... of elongation at the root apex and this was associated with extensive radial expansion of root epidermal cells. ßGlcY penetrated roots as far as the endodermis and it is suggested that the interaction of ßGlcY with AGPs in the load-bearing cell layers inhibited root elongation. When ßGlcY was added to carrot...

  12. A comparison of the low temperature transcriptomes and CBF regulons of three plant species that differ in freezing tolerance: Solanum commersonii, Solanum tuberosum, and Arabidopsis thaliana.

    Science.gov (United States)

    Carvallo, Marcela A; Pino, María-Teresa; Jeknic, Zoran; Zou, Cheng; Doherty, Colleen J; Shiu, Shin-Han; Chen, Tony H H; Thomashow, Michael F

    2011-07-01

    Solanum commersonii and Solanum tuberosum are closely related plant species that differ in their abilities to cold acclimate; whereas S. commersonii increases in freezing tolerance in response to low temperature, S. tuberosum does not. In Arabidopsis thaliana, cold-regulated genes have been shown to contribute to freezing tolerance, including those that comprise the CBF regulon, genes that are controlled by the CBF transcription factors. The low temperature transcriptomes and CBF regulons of S. commersonii and S. tuberosum were therefore compared to determine whether there might be differences that contribute to their differences in ability to cold acclimate. The results indicated that both plants alter gene expression in response to low temperature to similar degrees with similar kinetics and that both plants have CBF regulons composed of hundreds of genes. However, there were considerable differences in the sets of genes that comprised the low temperature transcriptomes and CBF regulons of the two species. Thus differences in cold regulatory programmes may contribute to the differences in freezing tolerance of these two species. However, 53 groups of putative orthologous genes that are cold-regulated in S. commersonii, S. tuberosum, and A. thaliana were identified. Given that the evolutionary distance between the two Solanum species and A. thaliana is 112-156 million years, it seems likely that these conserved cold-regulated genes-many of which encode transcription factors and proteins of unknown function-have fundamental roles in plant growth and development at low temperature.

  13. A comparison of the low temperature transcriptomes and CBF regulons of three plant species that differ in freezing tolerance: Solanum commersonii, Solanum tuberosum, and Arabidopsis thaliana

    Science.gov (United States)

    Pino, María-Teresa; Jeknić, Zoran; Zou, Cheng; Shiu, Shin-Han; Chen, Tony H. H.; Thomashow, Michael F.

    2011-01-01

    Solanum commersonii and Solanum tuberosum are closely related plant species that differ in their abilities to cold acclimate; whereas S. commersonii increases in freezing tolerance in response to low temperature, S. tuberosum does not. In Arabidopsis thaliana, cold-regulated genes have been shown to contribute to freezing tolerance, including those that comprise the CBF regulon, genes that are controlled by the CBF transcription factors. The low temperature transcriptomes and CBF regulons of S. commersonii and S. tuberosum were therefore compared to determine whether there might be differences that contribute to their differences in ability to cold acclimate. The results indicated that both plants alter gene expression in response to low temperature to similar degrees with similar kinetics and that both plants have CBF regulons composed of hundreds of genes. However, there were considerable differences in the sets of genes that comprised the low temperature transcriptomes and CBF regulons of the two species. Thus differences in cold regulatory programmes may contribute to the differences in freezing tolerance of these two species. However, 53 groups of putative orthologous genes that are cold-regulated in S. commersonii, S. tuberosum, and A. thaliana were identified. Given that the evolutionary distance between the two Solanum species and A. thaliana is 112–156 million years, it seems likely that these conserved cold-regulated genes—many of which encode transcription factors and proteins of unknown function—have fundamental roles in plant growth and development at low temperature. PMID:21511909

  14. Jasmonate and ethylene signaling mediate whitefly-induced interference with indirect plant defense in Arabidopsis thaliana

    NARCIS (Netherlands)

    Zhang, P.J.; Broekgaarden, C.; Zheng, S.J.; Snoeren, T.A.L.; Loon, van J.J.A.; Gols, R.; Dicke, M.

    2013-01-01

    Upon herbivore attack, plants activate an indirect defense, that is, the release of a complex mixture of volatiles that attract natural enemies of the herbivore. When plants are simultaneously exposed to two herbivore species belonging to different feeding guilds, one herbivore may interfere with th

  15. A highly efficient miPCR method for isolating FSTs from transgenic Arabidopsis thaliana plants

    Indian Academy of Sciences (India)

    Gennady V. Pogorelko; Oksana V. Fursova

    2008-08-01

    The exact localization of an insertion in the genome of transgenic plants obtained by Agrobacterium-mediated transformation is an integral part of most experiments aimed at studying these types of mutants. There are several methods for isolating unknown nucleotide sequences of genomic DNA which flank the borders of T-DNA integrated in the genome of plants. However, all the methods based on PCR have limitations which in some cases do not permit the desired objective to be achieved. We have developed a new technique for isolating flanking sequence tags (FSTs) via modified inverse PCR. This method is highly efficient and simple, but also retains the advantages of previously well-documented approaches.

  16. Crystallization and preliminary crystallographic analysis of Arabidopsis thaliana EDS1, a key component of plant immunity, in complex with its signalling partner SAG101.

    Science.gov (United States)

    Wagner, Stephan; Rietz, Steffen; Parker, Jane E; Niefind, Karsten

    2011-02-01

    In plants, the nucleocytoplasmic protein EDS1 (Enhanced disease susceptibility1) is an important regulator of innate immunity, coordinating host-cell defence and cell-death programs in response to pathogen attack. Arabidopsis thaliana EDS1 stabilizes and signals together with its partners PAD4 (Phytoalexin deficient4) and SAG101 (Senescence-associated gene101). Characterization of EDS1 molecular configurations in vitro and in vivo points to the formation of structurally and spatially distinct EDS1 homomeric dimers and EDS1 heteromeric complexes with either PAD4 or SAG101 as necessary components of the immune response. EDS1, PAD4 and SAG101 constitute a plant-specific protein family with a unique `EP' (EDS1-PAD4-specific) domain at their C-termini and an N-terminal domain resembling enzymes with an α/β-hydrolase fold. Here, the expression, purification and crystallization of a functional EDS1 complex formed by EDS1 and SAG101 from Arabidopsis thaliana are reported. The crystals belonged to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 101.8, b = 115.9, c = 122.8 Å, and diffracted to 3.5 Å resolution.

  17. Arabidopsis thaliana WRKY25, WRKY26, and WRKY33 coordinate induction of plant thermotolerance.

    Science.gov (United States)

    Li, Shujia; Fu, Qiantang; Chen, Ligang; Huang, Weidong; Yu, Diqiu

    2011-06-01

    Limited information is available regarding the exact function of specific WRKY transcription factors in plant responses to heat stress. We analyzed the roles of WRKY25, WRKY26, and WRKY33, three types of group I WRKY proteins, in the regulation of resistance to heat stress. Expression of WRKY25 and WRKY26 was induced upon treatment with high temperature, whereas WRKY33 expression was repressed. Heat-treated WRKY single mutants exhibited small responses, while wrky25wrky26 and wrky25wrky33 double mutants and the wrky25wrky26wrky33 triple mutants showed substantially increased susceptibility to heat stress, showing reduced germination, decreased survival, and elevated electrolyte leakage, compared with wild-type plants. In contrast, constitutive expression of WRKY25, WRKY26, or WRKY33 enhanced resistance to heat stress. Expression studies of selected heat-defense genes in single, double, and triple mutants, as well as in over-expressing lines, were correlated with their thermotolerance phenotypes and demonstrated that the three WRKY transcription factors modulate transcriptional changes of heat-inducible genes in response to heat treatment. In addition, our findings provided evidence that WRKY25, WRKY26, and WRKY33 were involved in regulation of the heat-induced ethylene-dependent response and demonstrated positive cross-regulation within these three genes. Together, these results indicate that WRKY25, WRKY26, and WRKY33 positively regulate the cooperation between the ethylene-activated and heat shock proteins-related signaling pathways that mediate responses to heat stress; and that these three proteins interact functionally and play overlapping and synergetic roles in plant thermotolerance.

  18. Differential contribution of plant-beneficial functions from Pseudomonas kilonensis F113 to root system architecture alterations in Arabidopsis thaliana and Zea mays.

    Science.gov (United States)

    Vacheron, Jordan; Desbrosses, Guilhem; Renoud, Sébastien; Padilla-Aguilar, Rosa-Maria; Walker, Vincent; Muller, Daniel; Prigent-Combaret, Claire

    2017-10-03

    Fluorescent pseudomonads are playing key roles in plant-bacteria symbiotic interactions due to the multiple plant-beneficial functions (PBFs) they are harboring. The relative contributions of PBFs to plant-stimulatory effects of the well-known PGPR Pseudomonas kilonensis F113 (formerly P. fluorescens F113) were investigated using a genetic approach. To this end, several deletion mutants were constructed: simple mutants ΔphlD (impaired in the biosynthesis of 2,4-diacetylphloroglucinol [DAPG]), ΔacdS (deficient in 1-aminocyclopropane-1-carboxylate [ACC] deaminase activity), Δgcd (glucose dehydrogenase deficient, impaired in phosphate solubilization), and ΔnirS (nitrite reductase deficient) and a quadruple mutant (deficient in the 4 PBFs mentioned above). Every PBF activity was quantified in the wild-type strain and the five deletion mutants. This approach revealed few functional interactions between PBFs in vitro. In particular, biosynthesis of glucose dehydrogenase severely reduced the production of DAPG. Contrariwise, the DAPG production impacted positively, but to a lesser extent, phosphate solubilization. Inoculation of the F113 wild-type strain on Arabidopsis thaliana Col-0 and maize seedlings modified the root architecture of both plants. Mutant strain inoculations revealed that the relative contribution of each PBF differed according to the measured plant traits, and that F113 plant-stimulatory effects did not correspond to the sum of each PBF relative contribution. Indeed, two PBF genes (ΔacdS and ΔnirS) had a significant impact on root system architecture from both model plants, whether in in vitro and in vivo conditions. The current work underlined that few F113 PBFs seem to interact between each other in the free-living bacterial cells, whereas they control in concert Arabidopsis thaliana and maize growth and development.

  19. Expression and Regulation of the Arabidopsis thaliana Cel1 Endo 1,4 β Glucanase Gene During Compatible Plant-Nematode Interactions

    Science.gov (United States)

    Sukno, Serenella; Shimerling, Orit; McCuiston, Jamie; Tsabary, Galit; Shani, Ziv; Shoseyov, Oded; Davis, Eric L

    2006-01-01

    The root-knot nematode Meloidogyne incognita is an obligate endoparasite of plant roots and stimulates elaborate modifications of selected root vascular cells to form giant cells for feeding. An Arabidopsis thaliana endoglucanase (Atcel1) promoter is activated in giant cells that were formed in Atcel1::UidA transgenic tobacco and Arabidopsis plants. Activity of the full-length Atcel1 promoter was detected in root and shoot elongation zones and in the lateral root primordia. Different 5’ and internal deletions of regions of the 1,673 bp Atcel1 promoter were each fused to the UidA reporter gene and transformed in tobacco, and roots of the transformants were inoculated with M. incognita to assay for GUS expression in giant cells and noninfected plant tissues. Comparison of the Atcel1 promoter deletion constructs showed that the region between −1,673 and −1,171 (fragment 1) was essential for Atcel1 promoter activity in giant cells and roots. Fragment 1 alone, however, was not sufficient for Atcel1 expression in giant cells or roots, suggesting that cis-acting elements in fragment 1 may function in consort with other elements within the Atcel1 promoter. Root-knot nematodes and giant cells developed normally within roots of Arabidopsis that expressed a functional antisense construct to Atcel1, suggesting that a functional redundancy in endoglucanase activity may represent another level of regulatory control of cell wall-modifying activity within nematode feeding cells. PMID:19259541

  20. Sulfonamides identified as plant immune-priming compounds in high-throughput chemical screening increase disease resistance in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Yoshiteru eNoutoshi

    2012-10-01

    Full Text Available Plant activators are agrochemicals that protect crops from diseases by activating the plant immune system. To isolate lead compounds for use as practical plant activators, we screened 2 different chemical libraries composed of various bioactive substances by using an established screening procedure that can selectively identify immune-priming compounds. We identified and characterized a group of sulfonamide compounds—sulfameter, sulfamethoxypyridazine, sulfabenzamide, and sulfachloropyridazine—among the various isolated candidate molecules. These sulfonamide compounds enhanced the avirulent Pseudomonas-induced cell death of Arabidopsis suspension cell cultures and increased disease resistance in Arabidopsis plants against both avirulent and virulent strains of the bacterium. These compounds did not prevent the growth of pathogenic bacteria in minimal liquid media at 200 µM. They also did not induce the expression of defense-related genes in Arabidopsis seedlings, at least not at 24 and 48 h after treatment, suggesting that they do not act as salicylic acid analogs. In addition, although sulfonamides are known to be folate biosynthesis inhibitors, the application of folate did not restore the potentiation effects of the sulfonamides on pathogen-induced cell death. Our data suggest that sulfonamides potentiate Arabidopsis disease resistance by their novel chemical properties.

  1. Measuring whole plant CO2 exchange with the environment reveals opposing effects of the gin2-1 mutation in shoots and roots of Arabidopsis thaliana.

    Science.gov (United States)

    Brauner, Katrin; Stutz, Simon; Paul, Martin; Heyer, Arnd G

    2015-01-01

    Using a cuvette for simultaneous measurement of net photosynthesis in above ground plant organs and root respiration we investigated the effect of reduced leaf glucokinase activity on plant carbon balance. The gin2-1 mutant of Arabidopsis thaliana is characterized by a 50% reduction of glucokinase activity in the shoot, while activity in roots is about fivefold higher and similar to wild type plants. High levels of sucrose accumulating in leaves during the light period correlated with elevated root respiration in gin2-1. Despite substantial respiratory losses in roots, growth retardation was moderate, probably because photosynthetic carbon fixation was simultaneously elevated in gin2-1. Our data indicate that futile cycling of sucrose in shoots exerts a reduction on net CO2 gain, but this is over-compensated by the prevention of exaggerated root respiration resulting from high sucrose concentration in leaf tissue.

  2. Arabidopsis thaliana and Thlaspi caerulescens respond comparably to low zinc supply

    NARCIS (Netherlands)

    Talukdar, S.; Aarts, M.G.M.

    2008-01-01

    The main objective of this research was to study the response of Arabidopsis thaliana L. and Thlaspi caerulescens J. & C. Presl to different Zn supplies. The A. thaliana plants were exposed to Zn-deficiency (0 and 0.05 ¿M Zn) and compared to the plants grown on media containing standard Zn (2

  3. Identification of a retroelement from the resurrection plant Boea hygrometrica that confers osmotic and alkaline tolerance in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Yan Zhao

    Full Text Available Functional genomic elements, including transposable elements, small RNAs and non-coding RNAs, are involved in regulation of gene expression in response to plant stress. To identify genomic elements that regulate dehydration and alkaline tolerance in Boea hygrometrica, a resurrection plant that inhabits drought and alkaline Karst areas, a genomic DNA library from B. hygrometrica was constructed and subsequently transformed into Arabidopsis using binary bacterial artificial chromosome (BIBAC vectors. Transgenic lines were screened under osmotic and alkaline conditions, leading to the identification of Clone L1-4 that conferred osmotic and alkaline tolerance. Sequence analyses revealed that L1-4 contained a 49-kb retroelement fragment from B. hygrometrica, of which only a truncated sequence was present in L1-4 transgenic Arabidopsis plants. Additional subcloning revealed that activity resided in a 2-kb sequence, designated Osmotic and Alkaline Resistance 1 (OAR1. In addition, transgenic Arabidopsis lines carrying an OAR1-homologue also showed similar stress tolerance phenotypes. Physiological and molecular analyses demonstrated that OAR1-transgenic plants exhibited improved photochemical efficiency and membrane integrity and biomarker gene expression under both osmotic and alkaline stresses. Short transcripts that originated from OAR1 were increased under stress conditions in both B. hygrometrica and Arabidopsis carrying OAR1. The relative copy number of OAR1 was stable in transgenic Arabidopsis under stress but increased in B. hygrometrica. Taken together, our results indicated a potential role of OAR1 element in plant tolerance to osmotic and alkaline stresses, and verified the feasibility of the BIBAC transformation technique to identify functional genomic elements from physiological model species.

  4. Identification of a retroelement from the resurrection plant Boea hygrometrica that confers osmotic and alkaline tolerance in Arabidopsis thaliana.

    Science.gov (United States)

    Zhao, Yan; Xu, Tao; Shen, Chun-Ying; Xu, Guang-Hui; Chen, Shi-Xuan; Song, Li-Zhen; Li, Mei-Jing; Wang, Li-Li; Zhu, Yan; Lv, Wei-Tao; Gong, Zhi-Zhong; Liu, Chun-Ming; Deng, Xin

    2014-01-01

    Functional genomic elements, including transposable elements, small RNAs and non-coding RNAs, are involved in regulation of gene expression in response to plant stress. To identify genomic elements that regulate dehydration and alkaline tolerance in Boea hygrometrica, a resurrection plant that inhabits drought and alkaline Karst areas, a genomic DNA library from B. hygrometrica was constructed and subsequently transformed into Arabidopsis using binary bacterial artificial chromosome (BIBAC) vectors. Transgenic lines were screened under osmotic and alkaline conditions, leading to the identification of Clone L1-4 that conferred osmotic and alkaline tolerance. Sequence analyses revealed that L1-4 contained a 49-kb retroelement fragment from B. hygrometrica, of which only a truncated sequence was present in L1-4 transgenic Arabidopsis plants. Additional subcloning revealed that activity resided in a 2-kb sequence, designated Osmotic and Alkaline Resistance 1 (OAR1). In addition, transgenic Arabidopsis lines carrying an OAR1-homologue also showed similar stress tolerance phenotypes. Physiological and molecular analyses demonstrated that OAR1-transgenic plants exhibited improved photochemical efficiency and membrane integrity and biomarker gene expression under both osmotic and alkaline stresses. Short transcripts that originated from OAR1 were increased under stress conditions in both B. hygrometrica and Arabidopsis carrying OAR1. The relative copy number of OAR1 was stable in transgenic Arabidopsis under stress but increased in B. hygrometrica. Taken together, our results indicated a potential role of OAR1 element in plant tolerance to osmotic and alkaline stresses, and verified the feasibility of the BIBAC transformation technique to identify functional genomic elements from physiological model species.

  5. Molecular characterization of two cloned nitrilases from Arabidopsis thaliana: key enzymes in biosynthesis of the plant hormone indole-3-acetic acid.

    Science.gov (United States)

    Bartling, D; Seedorf, M; Schmidt, R C; Weiler, E W

    1994-06-21

    As in maize [Wright, A.D., Sampson, M. B., Neuffer, M. G., Michalczuk, L., Slovin, J. P. & Cohen, J. D. (1991) Science 254, 998-1000], the major auxin of higher plants, indole-3-acetic acid, is synthesized mainly via a nontryptophan pathway in Arabidopsis thaliana [Normanly, J., Cohen, J. D. & Fink, G. R. (1993) Proc. Natl. Acad. Sci. USA 90, 10355-10359]. In the latter species, the hormone may be accessible from the glucosinolate glucobrassicin (indole-3-methyl glucosinolate) and from L-tryptophan via indoleacetaldoxime under special circumstances. In each case, indole-3-acetonitrile is the immediate precursor, which is converted into indole-3-acetic acid through the action of nitrilase (nitrile aminohydrolase, EC 3.5.5.1). The genome of A. thaliana contains two nitrilase genes. Nitrilase I had been cloned earlier in our laboratory. The cDNA for nitrilase II (PM255) was cloned and encodes an enzyme that converts indole-3-acetonitrile to indole-3-acetic acid, the plant hormone. We show that the intracellular location as well as the expression pattern of the two A. thaliana nitrilases are distinctly different. Nitrilase I is soluble and is expressed throughout development, but at a very low level during the fruiting stage, while nitrilase II is tightly associated with the plasma membrane, is barely detectable in young rosettes, but is strongly expressed during bolting, flowering, and especially fruit development. The results indicate that more than one pathway of indole-3-acetic acid biosynthesis via indole-3-acetonitrile exists in A. thaliana and that these pathways are differentially regulated throughout plant development.

  6. Phenotypic consequences of aneuploidy in Arabidopsis thaliana.

    Science.gov (United States)

    Henry, Isabelle M; Dilkes, Brian P; Miller, Eric S; Burkart-Waco, Diana; Comai, Luca

    2010-12-01

    Aneuploid cells are characterized by incomplete chromosome sets. The resulting imbalance in gene dosage has phenotypic consequences that are specific to each karyotype. Even in the case of Down syndrome, the most viable and studied form of human aneuploidy, the mechanisms underlying the connected phenotypes remain mostly unclear. Because of their tolerance to aneuploidy, plants provide a powerful system for a genome-wide investigation of aneuploid syndromes, an approach that is not feasible in animal systems. Indeed, in many plant species, populations of aneuploid individuals can be easily obtained from triploid individuals. We phenotyped a population of Arabidopsis thaliana aneuploid individuals containing 25 different karyotypes. Even in this highly heterogeneous population, we demonstrate that certain traits are strongly associated with the dosage of specific chromosome types and that chromosomal effects can be additive. Further, we identified subtle developmental phenotypes expressed in the diploid progeny of aneuploid parent(s) but not in euploid controls from diploid lineages. These results indicate long-term phenotypic consequences of aneuploidy that can persist after chromosomal balance has been restored. We verified the diploid nature of these individuals by whole-genome sequencing and discuss the possibility that trans-generational phenotypic effects stem from epigenetic modifications passed from aneuploid parents to their diploid progeny.

  7. Proteomic analyses of apoplastic proteins from germinating Arabidopsis thaliana pollen

    OpenAIRE

    Ge, Weina; Song, Yun; Zhang, Cuijun; Zhang, Yafang; Burlingame, Alma L; Guo, Yi

    2011-01-01

    Pollen grains play important roles in the reproductive processes of flowering plants. The roles of apoplastic proteins in pollen germination and in pollen tube growth are comparatively less well understood. To investigate the functions of apoplastic proteins in pollen germination, the global apoplastic proteins of mature and germinated Arabidopsis thaliana pollen grains were prepared for differential analyses by using 2-dimensional fluorescence difference gel electrophoresis (2-D DIGE) satura...

  8. The thanatos mutation in Arabidopsis thaliana cellulose synthase 3 (AtCesA3) has a dominant-negative effect on cellulose synthesis and plant growth.

    Science.gov (United States)

    Daras, Gerasimos; Rigas, Stamatis; Penning, Bryan; Milioni, Dimitra; McCann, Maureen C; Carpita, Nicholas C; Fasseas, Constantinos; Hatzopoulos, Polydefkis

    2009-01-01

    Genetic functional analyses of mutants in plant genes encoding cellulose synthases (CesAs) have suggested that cellulose deposition requires the activity of multiple CesA proteins. Here, a genetic screen has led to the identification of thanatos (than), a semi-dominant mutant of Arabidopsis thaliana with impaired growth of seedlings. Homozygous seedlings of than germinate and grow but do not survive. In contrast to other CesA mutants, heterozygous plants are dwarfed and display a radially swollen root phenotype. Cellulose content is reduced by approximately one-fifth in heterozygous and by two-fifths in homozygous plants, showing gene-dosage dependence. Map-based cloning revealed an amino acid substitution (P578S) in the catalytic domain of the AtCesA3 gene, indicating a critical role for this residue in the structure and function of the cellulose synthase complex. Ab initio analysis of the AtCesA3 subdomain flanking the conserved proline residue predicted that the amino acid substitution to serine alters protein secondary structure in the catalytic domain. Gene dosage-dependent expression of the AtCesA3 mutant gene in wild-type A. thaliana plants resulted in a than dominant-negative phenotype. We propose that the incorporation of a mis-folded CesA3 subunit into the cellulose synthase complex may stall or prevent the formation of functional rosette complexes.

  9. LC-MS metabolic profiling of Arabidopsis thaliana plant leaves and cell cultures: optimization of pre-LC-MS procedure parameters.

    Science.gov (United States)

    t'Kindt, Ruben; De Veylder, Lieven; Storme, Michael; Deforce, Dieter; Van Bocxlaer, Jan

    2008-08-01

    This study treats the optimization of methods for homogenizing Arabidopsis thaliana plant leaves as well as cell cultures, and extracting their metabolites for metabolomics analysis by conventional liquid chromatography electrospray ionization mass spectrometry (LC-ESI/MS). Absolute recovery, process efficiency and procedure repeatability have been compared between different pre-LC-MS homogenization/extraction procedures through the use of samples fortified before extraction with a range of representative metabolites. Hereby, the magnitude of the matrix effect observed in the ensuing LC-MS based metabolomics analysis was evaluated. Based on relative recovery and repeatability of key metabolites, comprehensiveness of extraction (number of m/z-retention time pairs) and clean-up potential of the approach (minimum matrix effects), the most appropriate sample pre-treatment was adopted. It combines liquid nitrogen homogenization for plant leaves with thermomixer based extraction using MeOH/H(2)O 80/20. As such, an efficient and highly reproducible LC-MS plant metabolomics set-up is achieved, as illustrated by the obtained results for both LC-MS (8.88%+/-5.16 versus 7.05%+/-4.45) and technical variability (12.53%+/-11.21 versus 9.31%+/-6.65) data in a comparative investigation of A. thaliana plant leaves and cell cultures, respectively.

  10. Demographic history of european populations of Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Olivier François

    2008-05-01

    Full Text Available The model plant species Arabidopsis thaliana is successful at colonizing land that has recently undergone human-mediated disturbance. To investigate the prehistoric spread of A. thaliana, we applied approximate Bayesian computation and explicit spatial modeling to 76 European accessions sequenced at 876 nuclear loci. We find evidence that a major migration wave occurred from east to west, affecting most of the sampled individuals. The longitudinal gradient appears to result from the plant having spread in Europe from the east approximately 10,000 years ago, with a rate of westward spread of approximately 0.9 km/year. This wave-of-advance model is consistent with a natural colonization from an eastern glacial refugium that overwhelmed ancient western lineages. However, the speed and time frame of the model also suggest that the migration of A. thaliana into Europe may have accompanied the spread of agriculture during the Neolithic transition.

  11. Photoprotection of PSI by Far-Red Light Against the Fluctuating Light-Induced Photoinhibition in Arabidopsis thaliana and Field-Grown Plants.

    Science.gov (United States)

    Kono, Masaru; Yamori, Wataru; Suzuki, Yoshihiro; Terashima, Ichiro

    2017-01-01

    It has been reported that PSI photoinhibition is induced even in wild-type plants of Arabidopsis thaliana, rice and other species by exposure of leaves to fluctuating light (FL) for a few hours. Because plants are exposed to FL in nature, they must possess protective mechanisms against the FL-induced photodamage. Here, using A. thaliana grown at various irradiances, we examined PSI photoprotection by far-red (FR) light at intensities comparable with those observed in nature. Dark-treated leaves were illuminated by red FL alternating high/low light at 1,200/30 µmol m-2 s-1 for 800 ms/10 s. By this FL treatment without FR light for 120 min, the level of photo-oxidizable P700 was decreased by 30% even in the plants grown at high irradiances. The addition of continuous FR light during the FL suppressed this damage almost completely. With FR light, P700 was kept in a more oxidized state in both low- and high-light phases. The protective effect of FR light was diminished more in mutants of the NADH dehydrogenase-like complex (NDH)-mediated cyclic electron flow around PSI (CEF-PSI) than in the PGR5 (proton gradient regulation 5)-mediated CEF-PSI, indicating that the NDH-mediated CEF-PSI would be a major contributor to PSI photoprotection in the presence of FR light. We also confirmed that PSI photoinhibition decreased with the increase in growth irradiance in A. thaliana and field-grown plants, and that this PSI photodamage was largely suppressed by addition of FR light. These results clearly indicate that the most effective PSI protection is realized in the presence of FR light. © The Author 2017. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  12. Quantitative divergence of the bacterial root microbiota in Arabidopsis thaliana relatives

    OpenAIRE

    Schlaeppi, K.; Dombrowski, N.; Oter, R. G.; Ver Loren van Themaat, E.; Schulze-Lefert, P

    2014-01-01

    All plants carry distinctive bacterial communities on and inside organs such as roots and leaves, collectively called the plant microbiota. How this microbiota diversifies in related plant species is unknown. We investigated the diversity of the bacterial root microbiota in the Brassicaceae family, including three Arabidopsis thaliana ecotypes, its sister species Arabidopsis halleri and Arabidopsis lyrata, and Cardamine hirsuta. We show that differences in root microbiota profiles between the...

  13. Transcriptional networks in the nitrate response of Arabidopsis thaliana.

    Science.gov (United States)

    Vidal, Elena A; Álvarez, José M; Moyano, Tomás C; Gutiérrez, Rodrigo A

    2015-10-01

    Nitrogen is an essential macronutrient for plants and its availability is a key determinant of plant growth and development and crop yield. Besides their nutritional role, N nutrients and metabolites are signals that activate signaling pathways that modulate many plant processes. Because the most abundant inorganic N source for plants in agronomic soils is nitrate, much of the work to understand plant N-signaling has focused on this nutrient. Over the last years, several studies defined a comprehensive catalog of nitrate-responsive genes, involved in nitrate transport, metabolism and a variety of other processes. Despite significant progress in recent years, primarily using Arabidopsis thaliana as a model system, the molecular mechanisms by which nitrate elicits changes in transcript abundance are still not fully understood. Here we highlight recent advancements in identifying key transcription factors and transcriptional mechanisms that orchestrate the gene expression response to changes in nitrate availability in A. thaliana.

  14. Ectopic overexpression of a novel Glycine soja stress-induced plasma membrane intrinsic protein increases sensitivity to salt and dehydration in transgenic Arabidopsis thaliana plants.

    Science.gov (United States)

    Wang, Xi; Cai, Hua; Li, Yong; Zhu, Yanming; Ji, Wei; Bai, Xi; Zhu, Dan; Sun, Xiaoli

    2015-01-01

    Plasma membrane intrinsic proteins (PIPs) belong to the aquaporin family and facilitate water movement across plasma membranes. Existing data indicate that PIP genes are associated with the abilities of plants to tolerate certain stress conditions. A review of our Glycine soja expressed sequence tag (EST) dataset revealed that abiotic stress stimulated expression of a PIP, herein designated as GsPIP2;1 (GenBank_Accn: FJ825766). To understand the roles of this PIP in stress tolerance, we generated a coding sequence for GsPIP2;1 by in silico elongation and cloned the cDNA by 5'-RACE. Semiquantitative RT-PCR showed that GsPIP2;1 expression was stimulated in G. soja leaves by cold, salt, or dehydration stress, whereas the same stresses suppressed GsPIP2;1 expression in the roots. Transgenic Arabidopsis thaliana plants overexpressing GsPIP2;1 grew normally under unstressed and cold conditions, but exhibited depressed tolerance to salt and dehydration stresses. Moreover, greater changes in water potential were detected in the transgenic A. thaliana shoots, implying that GsPIP2;1 may negatively impact stress tolerance by regulating water potential. These results, deviating from those obtained in previous reports, provide new insights into the relationship between PIPs and abiotic stress tolerance in plants.

  15. AtTCTP2, an Arabidopsis thaliana homolog of Translationally Controlled Tumor Protein, enhances in vitro plant regeneration

    OpenAIRE

    Roberto eToscano-Morales; Beatriz eXoconostle-Cázares; José Luis eCabrera-Ponce; Jesús eHinojosa-Moya; Jorge Luis eRuiz-Salas; Valentin eGalván-Gordillo; Ramon Gerardo eGuevara-González; Roberto eRuiz-Medrano

    2015-01-01

    The Translationally Controlled Tumor Protein (TCTP) is a central regulator of cell proliferation and differentiation in animals, and probably also in plants. Arabidopsis harbors two TCTP genes, AtTCTP1 (At3g16640), which is an important mitotic regulator, and AtTCTP2 (At3g05540), which is considered a pseudogene. Nevertheless, we have obtained evidence suggesting that this gene is functional. Indeed, a T-DNA insertion mutant, SALK_045146, displays a lethal phenotype during early rosette stage...

  16. Herkogamy and its effects on mating patterns in Arabidopsis thaliana.

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    Yonghai Luo

    Full Text Available The evolution of mating systems, which exhibit an extraordinary diversity in flowering plants, is of central interest in plant biology. Herkogamy, the spatial separation of sexual organs within flowers, is a widespread floral mechanism that is thought to be an adaptive trait reducing self-pollination in hermaphroditic plants. In contrast with previous studies of herkogamy that focused on plants with relatively large floral displays, we here characterized herkogamy in Arabidopsis thaliana, a model plant with a strong selfing syndrome. Developmental features, reproductive consequences, and genetic architecture of herkogamy were exploited using naturally variable A. thaliana accessions, under both greenhouse and natural conditions. Our results demonstrate that the degree of herkogamy can strongly influence the mating patterns of A. thaliana: approach herkogamy can effectively promote outcrossing, no herkogamy is also capable of enhancing the opportunity for outcrossing, and reverse herkogamy facilitates efficient self-pollination. In addition, we found that the expression of herkogamy in A. thaliana was environment-dependent and regulated by multiple quantitative trait loci. This study reveals how minor modifications in floral morphology may cause dramatic changes in plant mating patterns, provides new insights into the function of herkogamy, and suggests the way for dissecting the genetic basis of this important character in a model plant.

  17. Circadian waves of expression of the APRR1/TOC1 family of pseudo-response regulators in Arabidopsis thaliana: insight into the plant circadian clock.

    Science.gov (United States)

    Matsushika, A; Makino, S; Kojima, M; Mizuno, T

    2000-09-01

    The Arabidopsis pseudo-response regulator, APRR1, has a unique structural design containing a pseudo-receiver domain and a C-terminal CONSTANS motif. This protein was originally characterized as a presumed component of the His-to-Asp phosphorelay systems in Arabidopsis thaliana. Recently, it was reported that APRR1 is identical to the TOC1 gene product, a mutational lesion of which affects the periods of many circadian rhythms in Arabidopsis plants. TOC1 is believed to be a component of the presumed circadian clock (or central oscillator). Based on these facts, in this study four more genes, each encoding a member of the APRR1/TOC1 family of pseudo-response regulators were identified and characterized with special reference to circadian rhythms. It was found that all these members of the APRR1/TOC1 family (APRR1, APRR3, APRR5, APRR7, and APRR9) are subjected to a circadian rhythm at the level of transcription. Furthermore, in a given 24 h period, the APRR-mRNAs started accumulating sequentially after dawn with 2-3 h intervals in the order of APRR9-->APRR7-->APRR5-->APRR3-->APRR1. These sequential events of transcription, termed 'circadian waves of APRR1/TOCI', were not significantly affected by the photoperiod conditions, if any (e.g. both long and short days), and the expression of APRR9 was first boosted always after dawn. Among these APRRs, in fact, only the expression of APRR9 was rapidly and transiently induced also by white light, whereas such light responses of others were very dull, if any. These results collectively support the view that these members of the APRR1/TOC1 family are together all involved in an as yet unknown mechanism underlying the Arabidopsis circadian clock. Here we propose that the circadian waves of the APRR1/TOC1 family members are most likely a molecular basis of such a biological clock in higher plants.

  18. Characterization of the Nrt2.6 gene in Arabidopsis thaliana: a link with plant response to biotic and abiotic stress.

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    Julie Dechorgnat

    Full Text Available The high affinity nitrate transport system in Arabidopsis thaliana involves one gene and potentially seven genes from the NRT1 and NRT2 family, respectively. Among them, NRT2.1, NRT2.2, NRT2.4 and NRT2.7 proteins have been shown to transport nitrate and are localized on the plasmalemma or the tonoplast membranes. NRT2.1, NRT2.2 and NRT2.4 play a role in nitrate uptake from soil solution by root cells while NRT2.7 is responsible for nitrate loading in the seed vacuole. We have undertaken the functional characterization of a third member of the family, the NRT2.6 gene. NRT2.6 was weakly expressed in most plant organs and its expression was higher in vegetative organs than in reproductive organs. Contrary to other NRT2 members, NRT2.6 expression was not induced by limiting but rather by high nitrogen levels, and no nitrate-related phenotype was found in the nrt2.6-1 mutant. Consistently, the over-expression of the gene failed to complement the nitrate uptake defect of an nrt2.1-nrt2.2 double mutant. The NRT2.6 expression is induced after inoculation of Arabidopsis thaliana by the phytopathogenic bacterium Erwinia amylovora. Interestingly, plants with a decreased NRT2.6 expression showed a lower tolerance to pathogen attack. A correlation was found between NRT2.6 expression and ROS species accumulation in response to infection by E. amylovora and treatment with the redox-active herbicide methyl viologen, suggesting a probable link between NRT2.6 activity and the production of ROS in response to biotic and abiotic stress.

  19. Arsenic uptake and speciation in Arabidopsis thaliana under hydroponic conditions.

    Science.gov (United States)

    Park, Jin Hee; Han, Young-Soo; Seong, Hye Jin; Ahn, Joo Sung; Nam, In-Hyun

    2016-07-01

    Arsenic (As) uptake and species in Arabidopsis thaliana were evaluated under hydroponic conditions. Plant nutrient solutions were treated with arsenite [As(III)] or arsenate [As(V)], and aqueous As speciation was conducted using a solid phase extraction (SPE) cartridge. Arabidopsis reduced As(V) to As(III) in the nutrient solution, possibly due to root exudates such as organic acids or the efflux of As(III) from plant roots after in vivo reduction of As(V) to As(III). Arsenic uptake by Arabidopsis was associated with increased levels of Ca and Fe, and decreased levels of K in plant tissues. Arsenic in Arabidopsis mainly occurred as As(III), which was coordinated with oxygen and sulfur based on XANES and EXAFS results. The existence of As(III)O and As(III)S in EXAFS indicates partial biotransformation of As(III)O to a sulfur-coordinated form because of limited amount of glutathione in plants. Further understanding the mechanism of As biotransformation in Arabidopsis may help to develop measures that can mitigate As toxicity via genetic engineering. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. 3D Plant Cell Architecture of Arabidopsis thaliana (Brassicaceae Using Focused Ion Beam–Scanning Electron Microscopy

    Directory of Open Access Journals (Sweden)

    Bhawana

    2014-06-01

    Full Text Available Premise of the study: Focused ion beam–scanning electron microscopy (FIB-SEM combines the ability to sequentially mill the sample surface and obtain SEM images that can be used to create 3D renderings with micron-level resolution. We have applied FIB-SEM to study Arabidopsis cell architecture. The goal was to determine the efficacy of this technique in plant tissue and cellular studies and to demonstrate its usefulness in studying cell and organelle architecture and distribution. Methods: Seed aleurone, leaf mesophyll, stem cortex, root cortex, and petal lamina from Arabidopsis were fixed and embedded for electron microscopy using protocols developed for animal tissues and modified for use with plant cells. Each sample was sectioned using the FIB and imaged with SEM. These serial images were assembled to produce 3D renderings of each cell type. Results: Organelles such as nuclei and chloroplasts were easily identifiable, and other structures such as endoplasmic reticula, lipid bodies, and starch grains were distinguishable in each tissue. Discussion: The application of FIB-SEM produced 3D renderings of five plant cell types and offered unique views of their shapes and internal content. These results demonstrate the usefulness of FIB-SEM for organelle distribution and cell architecture studies.

  1. Proteomic analyses of the interaction between the plant-growth promoting rhizobacterium Paenibacillus polymyxa E681 and Arabidopsis thaliana.

    Science.gov (United States)

    Kwon, Young Sang; Lee, Dong Yeol; Rakwal, Randeep; Baek, Seong-Bum; Lee, Jeom Ho; Kwak, Youn-Sig; Seo, Jong-Su; Chung, Woo Sik; Bae, Dong-Won; Kim, Sang Gon

    2016-01-01

    Plant growth-promoting rhizobacteria (PGPR) facilitate the plant growth and enhance their induced systemic resistance (ISR) against a variety of environmental stresses. In this study, we carried out integrative analyses on the proteome, transcriptome, and metabolome to investigate Arabidopsis root and shoot responses to the well-known PGPR strain Paenibacillus polymyxa (P. polymyxa) E681. Shoot fresh and root dry weights were increased, whereas root length was decreased by treatment with P. polymyxa E681. 2DE approach in conjunction with MALDI-TOF/TOF analysis revealed a total of 41 (17 spots in root, 24 spots in shoot) that were differentially expressed in response to P. polymyxa E681. Biological process- and molecular function-based bioinformatics analysis resulted in their classification into seven different protein groups. Of these, 36 proteins including amino acid metabolism, antioxidant, defense and stress response, photosynthesis, and plant hormone-related proteins were up-regulated, whereas five proteins including three carbohydrate metabolism- and one amino acid metabolism-related, and one unknown protein were down-regulated, respectively. A good correlation was observed between protein and transcript abundances for the 12 differentially expressed proteins during interactions as determined by qPCR analysis. Metabolite analysis using LC-MS/MS revealed highly increased levels of tryptophan, indole-3-acetonitrile (IAN), indole-3-acetic acid (IAA), and camalexin in the treated plants. Arabidopsis plant inoculated P. polymyxa E681 also showed resistance to Botrytis cinerea infection. Taken together these results suggest that P. polymyxa E681 may promote plant growth by induced metabolism and activation of defense-related proteins against fungal pathogen.

  2. Multi-element bioimaging of Arabidopsis thaliana roots

    DEFF Research Database (Denmark)

    Persson, Daniel Olof; Chen, Anle; Aarts, Mark G.M.

    2016-01-01

    Better understanding of root function is central for the development of plants with more efficient nutrient uptake and translocation. We here present a method for multielement bioimaging at the cellular level in roots of the genetic model system Arabidopsis (Arabidopsis thaliana). Using...... conventional protocols for microscopy, we observed that diffusible ions such as potassium and sodium were lost during sample dehydration. Thus, we developed a protocol that preserves ions in their native, cellular environment. Briefly, fresh roots are encapsulated in paraffin, cryo-sectioned, and freeze dried...... transport in roots. Being applicable to Arabidopsis, the molecular and genetic approaches available in this system can now be fully exploited in order to gain a better mechanistic understanding of these processes....

  3. The rhizobacterial elicitor acetoin induces systemic resistance in Arabidopsis thaliana.

    Science.gov (United States)

    Rudrappa, Thimmaraju; Biedrzycki, Meredith L; Kunjeti, Sridhara G; Donofrio, Nicole M; Czymmek, Kirk J; Paré, Paul W; Bais, Harsh P

    2010-03-01

    The majority of plant growth promoting rhizobacteria (PGPR) confer plant immunity against a wide range of foliar diseases by activating plant defences that reduce a plant's susceptibility to pathogen attack. Here we show that Arabidopsis thaliana (Col-0) plants exposed to Bacillus subtilis strain FB17 (hereafter FB17), results in reduced disease severity against Pseudomonas syringae pv. tomato DC3000 (hereafter DC3000) compared to plants without FB17 treatment. Exogenous application of the B. subtilis derived elicitor, acetoin (3-hydroxy-2-butanone), was found to trigger induced systemic resistance (ISR) and protect plants against DC3000 pathogenesis. Moreover, B. subtilis acetoin biosynthetic mutants that emitted reduced levels of acetoin conferred reduced protection to A. thaliana against pathogen infection. Further analysis using FB17 and defense-compromised mutants of A. thaliana indicated that resistance to DC3000 occurs via NPR1 and requires salicylic acid (SA)/ethylene (ET) whereas jasmonic acid (JA) is not essential. This study provides new insight into the role of rhizo-bacterial volatile components as elicitors of defense responses in plants.

  4. AtTCTP2, an Arabidopsis thaliana homolog of Translationally Controlled Tumor Protein, enhances in vitro plant regeneration

    Directory of Open Access Journals (Sweden)

    Roberto eToscano-Morales

    2015-07-01

    Full Text Available The Translationally Controlled Tumor Protein (TCTP is a central regulator of cell proliferation and differentiation in animals, and probably also in plants. Arabidopsis harbors two TCTP genes, AtTCTP1 (At3g16640, which is an important mitotic regulator, and AtTCTP2 (At3g05540, which is considered a pseudogene. Nevertheless, we have obtained evidence suggesting that this gene is functional. Indeed, a T-DNA insertion mutant, SALK_045146, displays a lethal phenotype during early rosette stage. Also, both the AtTCTP2 promoter and structural gene are functional, and heterozygous plants show delayed development. AtTCTP1 cannot compensate for the loss of AtTCTP2, since the accumulation levels of the AtTCTP1 transcript are even higher in heterozygous plants than in wild-type plants. Leaf explants transformed with Agrobacterium rhizogenes harboring AtTCTP2, but not AtTCTP1, led to whole plant regeneration with a high frequency. Insertion of a sequence present in AtTCTP1 but absent in AtTCP2 demonstrates that this suppresses the capacity for plant regeneration; also, this phenomenon requires the presence of TCTP (AtTCTP1 or 2 in the nuclei of root cells. This confirms that AtTCTP2 is not a pseudogene and suggests the involvement of certain TCTP isoforms in vegetative reproduction in some plant species.

  5. AtTCTP2, an Arabidopsis thaliana homolog of Translationally Controlled Tumor Protein, enhances in vitro plant regeneration

    Science.gov (United States)

    Toscano-Morales, Roberto; Xoconostle-Cázares, Beatriz; Cabrera-Ponce, José L.; Hinojosa-Moya, Jesús; Ruiz-Salas, Jorge L.; Galván-Gordillo, Santiago V.; Guevara-González, Ramón G.; Ruiz-Medrano, Roberto

    2015-01-01

    The Translationally Controlled Tumor Protein (TCTP) is a central regulator of cell proliferation and differentiation in animals, and probably also in plants. Arabidopsis harbors two TCTP genes, AtTCTP1 (At3g16640), which is an important mitotic regulator, and AtTCTP2 (At3g05540), which is considered a pseudogene. Nevertheless, we have obtained evidence suggesting that this gene is functional. Indeed, a T-DNA insertion mutant, SALK_045146, displays a lethal phenotype during early rosette stage. Also, both the AtTCTP2 promoter and structural gene are functional, and heterozygous plants show delayed development. AtTCTP1 cannot compensate for the loss of AtTCTP2, since the accumulation levels of the AtTCTP1 transcript are even higher in heterozygous plants than in wild-type plants. Leaf explants transformed with Agrobacterium rhizogenes harboring AtTCTP2, but not AtTCTP1, led to whole plant regeneration with a high frequency. Insertion of a sequence present in AtTCTP1 but absent in AtTCTP2 demonstrates that it suppresses the capacity for plant regeneration; also, this phenomenon is enhanced by the presence of TCTP (AtTCTP1 or 2) in the nuclei of root cells. This confirms that AtTCTP2 is not a pseudogene and suggests the involvement of certain TCTP isoforms in vegetative reproduction in some plant species. PMID:26191065

  6. Systemic resistance induced by volatile organic compounds emitted by plant growth-promoting fungi in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Hushna Ara Naznin

    Full Text Available Volatile organic compounds (VOC were extracted and identified from plant growth-promoting fungi (PGPF, Phoma sp., Cladosporium sp. and Ampelomyces sp., using gas chromatography-mass spectrometry (GC-MS. Among the three VOC extracted, two VOC blends (emitted from Ampelomyces sp. and Cladosporium sp. significantly reduced disease severity in Arabidopsis plants against Pseudomonas syringae pv. tomato DC3000 (Pst. Subsequently, m-cresol and methyl benzoate (MeBA were identified as major active volatile compounds from Ampelomyces sp. and Cladosporium sp., respectively, and found to elicit induced systemic resistance (ISR against the pathogen. Molecular signaling for disease suppression by the VOC were investigated by treating different mutants and transgenic Arabidopsis plants impaired in salicylic acid (SA or Jasmonic acid (JA/ethylene (ET signaling pathways with m-cresol and MeBA followed by challenge inoculation with Pst. Results show that the level of protection was significantly lower when JA/ET-impaired mutants were treated with MeBA, and in SA-, and JA/ET-disrupted mutants after m-cresol treatment, indicating the involvement of these signal transduction pathways in the ISR primed by the volatiles. Analysis of defense-related genes by real-time qRT-PCR showed that both the SA-and JA-signaling pathways combine in the m-cresol signaling of ISR, whereas MeBA is mainly involved in the JA-signaling pathway with partial recruitment of SA-signals. The ET-signaling pathway was not employed in ISR by the volatiles. Therefore, this study identified two novel volatile components capable of eliciting ISR that may be promising candidates in biological control strategy to protect plants from diseases.

  7. Systemic resistance induced by volatile organic compounds emitted by plant growth-promoting fungi in Arabidopsis thaliana.

    Science.gov (United States)

    Naznin, Hushna Ara; Kiyohara, Daigo; Kimura, Minako; Miyazawa, Mitsuo; Shimizu, Masafumi; Hyakumachi, Mitsuro

    2014-01-01

    Volatile organic compounds (VOC) were extracted and identified from plant growth-promoting fungi (PGPF), Phoma sp., Cladosporium sp. and Ampelomyces sp., using gas chromatography-mass spectrometry (GC-MS). Among the three VOC extracted, two VOC blends (emitted from Ampelomyces sp. and Cladosporium sp.) significantly reduced disease severity in Arabidopsis plants against Pseudomonas syringae pv. tomato DC3000 (Pst). Subsequently, m-cresol and methyl benzoate (MeBA) were identified as major active volatile compounds from Ampelomyces sp. and Cladosporium sp., respectively, and found to elicit induced systemic resistance (ISR) against the pathogen. Molecular signaling for disease suppression by the VOC were investigated by treating different mutants and transgenic Arabidopsis plants impaired in salicylic acid (SA) or Jasmonic acid (JA)/ethylene (ET) signaling pathways with m-cresol and MeBA followed by challenge inoculation with Pst. Results show that the level of protection was significantly lower when JA/ET-impaired mutants were treated with MeBA, and in SA-, and JA/ET-disrupted mutants after m-cresol treatment, indicating the involvement of these signal transduction pathways in the ISR primed by the volatiles. Analysis of defense-related genes by real-time qRT-PCR showed that both the SA-and JA-signaling pathways combine in the m-cresol signaling of ISR, whereas MeBA is mainly involved in the JA-signaling pathway with partial recruitment of SA-signals. The ET-signaling pathway was not employed in ISR by the volatiles. Therefore, this study identified two novel volatile components capable of eliciting ISR that may be promising candidates in biological control strategy to protect plants from diseases.

  8. The scale of population structure in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Alexander Platt

    2010-02-01

    Full Text Available The population structure of an organism reflects its evolutionary history and influences its evolutionary trajectory. It constrains the combination of genetic diversity and reveals patterns of past gene flow. Understanding it is a prerequisite for detecting genomic regions under selection, predicting the effect of population disturbances, or modeling gene flow. This paper examines the detailed global population structure of Arabidopsis thaliana. Using a set of 5,707 plants collected from around the globe and genotyped at 149 SNPs, we show that while A. thaliana as a species self-fertilizes 97% of the time, there is considerable variation among local groups. This level of outcrossing greatly limits observed heterozygosity but is sufficient to generate considerable local haplotypic diversity. We also find that in its native Eurasian range A. thaliana exhibits continuous isolation by distance at every geographic scale without natural breaks corresponding to classical notions of populations. By contrast, in North America, where it exists as an exotic species, A. thaliana exhibits little or no population structure at a continental scale but local isolation by distance that extends hundreds of km. This suggests a pattern for the development of isolation by distance that can establish itself shortly after an organism fills a new habitat range. It also raises questions about the general applicability of many standard population genetics models. Any model based on discrete clusters of interchangeable individuals will be an uneasy fit to organisms like A. thaliana which exhibit continuous isolation by distance on many scales.

  9. A role for katanin in plant cell division: microtubule organization in dividing root cells of fra2 and lue1Arabidopsis thaliana mutants.

    Science.gov (United States)

    Panteris, Emmanuel; Adamakis, Ioannis-Dimosthenis S; Voulgari, Georgia; Papadopoulou, Galini

    2011-07-01

    Severing of microtubules by katanin has proven to be crucial for cortical microtubule organization in elongating and differentiating plant cells. On the contrary, katanin is currently not considered essential during cell division in plants as it is in animals. However, defects in cell patterning have been observed in katanin mutants, implying a role for it in dividing plant cells. Therefore, microtubule organization was studied in detail by immunofluorescence in dividing root cells of fra2 and lue1 katanin mutants of Arabidopsis thaliana. In both, early preprophase bands consisted of poorly aligned microtubules, prophase spindles were multipolar, and the microtubules of expanding phragmoplasts were elongated, bended toward and connected to the surface of daughter nuclei. Accordingly, severing by katanin seems to be necessary for the proper organization of these microtubule arrays. In both fra2 and lue1, metaphase/anaphase spindles and initiating phragmoplasts exhibited typical organization. However, they were obliquely oriented more frequently than in the wild type. It is proposed that this oblique orientation may be due to prophase spindle multipolarity and results in a failure of the cell plate to follow the predetermined division plane, during cytokinesis, producing oblique cell walls in the roots of both mutants. It is therefore concluded that, like in animal cells, katanin is important for plant cell division, influencing the organization of several microtubule arrays. Moreover, failure in microtubule severing indirectly affects the orientation of the division plane. Copyright © 2011 Wiley-Liss, Inc.

  10. Transcriptome response analysis of Arabidopsis thaliana to leafminer (Liriomyza huidobrensis

    Directory of Open Access Journals (Sweden)

    Zhang Sufang

    2012-12-01

    Full Text Available Abstract Background Plants have evolved a complicated resistance system and exhibit a variety of defense patterns in response to different attackers. Previous studies have shown that responses of plants to chewing insects and phloem-feeding insects are significantly different. Less is known, however, regarding molecular responses to leafminer insects. To investigate plant transcriptome response to leafminers, we selected the leafminer Liriomyza huidobrensis, which has a special feeding pattern more similar to pathogen damage than that of chewing insects, as a model insect, and Arabidopsis thaliana as a response plant. Results We first investigated local and systemic responses of A. thaliana to leafminer feeding using an Affymetrix ATH1 genome array. Genes related to metabolic processes and stimulus responses were highly regulated. Most systemically-induced genes formed a subset of the local response genes. We then downloaded gene expression data from online databases and used hierarchical clustering to explore relationships among gene expression patterns in A. thaliana damaged by different attackers. Conclusions Our results demonstrate that plant response patterns are strongly coupled to damage patterns of attackers.

  11. The pattern of polymorphism in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    2005-07-01

    Full Text Available We resequenced 876 short fragments in a sample of 96 individuals of Arabidopsis thaliana that included stock center accessions as well as a hierarchical sample from natural populations. Although A. thaliana is a selfing weed, the pattern of polymorphism in general agrees with what is expected for a widely distributed, sexually reproducing species. Linkage disequilibrium decays rapidly, within 50 kb. Variation is shared worldwide, although population structure and isolation by distance are evident. The data fail to fit standard neutral models in several ways. There is a genome-wide excess of rare alleles, at least partially due to selection. There is too much variation between genomic regions in the level of polymorphism. The local level of polymorphism is negatively correlated with gene density and positively correlated with segmental duplications. Because the data do not fit theoretical null distributions, attempts to infer natural selection from polymorphism data will require genome-wide surveys of polymorphism in order to identify anomalous regions. Despite this, our data support the utility of A. thaliana as a model for evolutionary functional genomics.

  12. Piriformospora indica Stimulates Root Metabolism of Arabidopsis thaliana.

    Science.gov (United States)

    Strehmel, Nadine; Mönchgesang, Susann; Herklotz, Siska; Krüger, Sylvia; Ziegler, Jörg; Scheel, Dierk

    2016-07-08

    Piriformospora indica is a root-colonizing fungus, which interacts with a variety of plants including Arabidopsis thaliana. This interaction has been considered as mutualistic leading to growth promotion of the host. So far, only indolic glucosinolates and phytohormones have been identified as key players. In a comprehensive non-targeted metabolite profiling study, we analyzed Arabidopsis thaliana's roots, root exudates, and leaves of inoculated and non-inoculated plants by ultra performance liquid chromatography/electrospray ionization quadrupole-time-of-flight mass spectrometry (UPLC/(ESI)-QTOFMS) and gas chromatography/electron ionization quadrupole mass spectrometry (GC/EI-QMS), and identified further biomarkers. Among them, the concentration of nucleosides, dipeptides, oligolignols, and glucosinolate degradation products was affected in the exudates. In the root profiles, nearly all metabolite levels increased upon co-cultivation, like carbohydrates, organic acids, amino acids, glucosinolates, oligolignols, and flavonoids. In the leaf profiles, we detected by far less significant changes. We only observed an increased concentration of organic acids, carbohydrates, ascorbate, glucosinolates and hydroxycinnamic acids, and a decreased concentration of nitrogen-rich amino acids in inoculated plants. These findings contribute to the understanding of symbiotic interactions between plant roots and fungi of the order of Sebacinales and are a valid source for follow-up mechanistic studies, because these symbioses are particular and clearly different from interactions of roots with mycorrhizal fungi or dark septate endophytes.

  13. Arabidopsis thaliana glucuronosyltransferase in family GT14

    DEFF Research Database (Denmark)

    Dilokpimol, Adiphol; Geshi, Naomi

    2014-01-01

    of glucuronic acid residues to β-1,3- and β-1,6-linked galactans of arabinogalactan (Knoch et al. 2013). The knockout mutant of this gene resulted in the enhanced growth rate of hypocotyls and roots of seedlings, suggesting an involvement of AtGlcAT 14A in cell elongation. AtGlcAt14A belongs to the family GT14...... in the Carbohydrate Active Enzyme database (CAZy; www.cazy.org), in which a total of 11 proteins, including AtGLCAT 14A, are classified from Arabidopsis thaliana. In this paper, we report the enzyme activities for the rest of the Arabidopsis GT14 isoforms, analyzed in the same way as for AtGlcAT 14A. Evidently, two...... other Arabidopsis GT14 isoforms, At5g15050 and At2g37585, also possess the glucuronosyltransferase activity adding glucuronic acid residues to β-1,3- and β-1,6-linked galactans. Therefore, we named At5g15050 and At2g37585 as AtGlcAT 14B and AtGlcAT 14C, respectively. © 2014 Landes Bioscience....

  14. Comparative differential gene expression analysis of nucleus-encoded proteins for Rafflesia cantleyi against Arabidopsis thaliana

    Science.gov (United States)

    Ng, Siuk-Mun; Lee, Xin-Wei; Wan, Kiew-Lian; Firdaus-Raih, Mohd

    2015-09-01

    Regulation of functional nucleus-encoded proteins targeting the plastidial functions was comparatively studied for a plant parasite, Rafflesia cantleyi versus a photosynthetic plant, Arabidopsis thaliana. This study involved two species of different feeding modes and different developmental stages. A total of 30 nucleus-encoded proteins were found to be differentially-regulated during two stages in the parasite; whereas 17 nucleus-encoded proteins were differentially-expressed during two developmental stages in Arabidopsis thaliana. One notable finding observed for the two plants was the identification of genes involved in the regulation of photosynthesis-related processes where these processes, as expected, seem to be present only in the autotroph.

  15. Transgenic Arabidopsis thaliana plants expressing a β-1,3-glucanase from sweet sorghum (Sorghum bicolor L.) show reduced callose deposition and increased tolerance to aluminium toxicity.

    Science.gov (United States)

    Zhang, Hui; Shi, Wu Liang; You, Jiang Feng; Bian, Ming Di; Qin, Xiao Mei; Yu, Hui; Liu, Qing; Ryan, Peter R; Yang, Zhen Ming

    2015-06-01

    Seventy-one cultivars of sweet sorghum (Sorghum bicolor L.) were screened for aluminium (Al) tolerance by measuring relative root growth (RRG). Two contrasting cultivars, ROMA (Al tolerant) and POTCHETSTRM (Al sensitive), were selected to study shorter term responses to Al stress. POTCHETSTRM had higher callose synthase activity, lower β-1,3-glucanase activity and more callose deposition in the root apices during Al treatment compared with ROMA. We monitored the expression of 12 genes involved in callose synthesis and degradation and found that one of these, SbGlu1 (Sb03g045630.1), which encodes a β-1,3-glucanase enzyme, best explained the contrasting deposition of callose in ROMA and POTCHETSTRM during Al treatment. Full-length cDNAs of SbGlu1 was prepared from ROMA and POTCHETSTRM and expressed in Arabidopsis thaliana using the constitutive cauliflower mosaic virus (CaMV) 35S promoter. Independent transgenic lines displayed significantly greater Al tolerance than wild-type plants and vector-only controls. This phenotype was associated with greater total β-1,3-glucanase activity, less Al accumulation and reduced callose deposition in the roots. These results suggest that callose production is not just an early indicator of Al stress in plants but likely to be part of the toxicity pathway that leads to the inhibition of root growth.

  16. Role of the plant-specific endoplasmic reticulum stress-inducible gene TIN1 in the formation of pollen surface structure in Arabidopsis thaliana

    KAUST Repository

    Iwata, Yuji

    2012-01-01

    Accumulation of unfolded proteins in the endoplasmic reticulum (ER) of eukaryotic cells triggers the transcriptional activation of ER-resident molecular chaperones and folding enzymes to maintain cellular homeostasis. This process is known as the ER stress response or the unfolded protein response. We have identified tunicamycin induced 1 (TIN1), a plant-specific ER stress-inducible Arabidopsis thaliana gene. The TIN1 protein is localized in the ER; however, its molecular function has yet to be clarified. In this study, we performed functional analysis of TIN1 in planta. RT-PCR analysis showed that TIN1 is highly expressed in pollen. Analysis using the β-glucuronidase reporter gene demonstrated that the TIN1 promoter is active throughout pollen development, peaking at the time of flowering and in an ovule of an open flower. Although a T-DNA insertion mutant of TIN1 grows normally under ambient laboratory conditions, abnormal pollen surface morphology was observed under a scanning electron microscope. Based on the current and previous observations, a possible physiological function of TIN1 during pollen development is discussed. © 2012 The Japanese Society for Plant Cell and Molecular Biology.

  17. Enhancing pterin and para-aminobenzoate content is not sufficient to successfully biofortify potato tubers and Arabidopsis thaliana plants with folate.

    Science.gov (United States)

    Blancquaert, Dieter; Storozhenko, Sergei; Van Daele, Jeroen; Stove, Christophe; Visser, Richard G F; Lambert, Willy; Van Der Straeten, Dominique

    2013-09-01

    Folates are important cofactors in one-carbon metabolism in all living organisms. Since only plants and micro- organisms are capable of biosynthesizing folates, humans depend entirely on their diet as a folate source. Given the low folate content of several staple crop products, folate deficiency affects regions all over the world. Folate biofortification of staple crops through enhancement of pterin and para-aminobenzoate levels, precursors of the folate biosynthesis pathway, was reported to be successful in tomato and rice. This study shows that the same strategy is not sufficient to enhance folate content in potato tubers and Arabidopsis thaliana plants and concludes that other steps in folate biosynthesis and/or metabolism need to be engineered to result in substantial folate accumulation. The findings provide a plausible explanation why, more than half a decade after the proof of concept in rice and tomato, successful folate biofortification of other food crops through enhancement of para-aminobenzoate and pterin content has not been reported thus far. A better understanding of the folate pathway is required in order to determine an engineering strategy that can be generalized to most staple crops.

  18. Interactions between selenium and sulphur nutrition in Arabidopsis thaliana.

    Science.gov (United States)

    White, P J; Bowen, H C; Parmaguru, P; Fritz, M; Spracklen, W P; Spiby, R E; Meacham, M C; Mead, A; Harriman, M; Trueman, L J; Smith, B M; Thomas, B; Broadley, M R

    2004-08-01

    Selenium (Se) is an essential plant micronutrient, but is toxic at high tissue concentrations. It is chemically similar to sulphur (S), an essential plant macronutrient. The interactions between Se and S nutrition were investigated in the model plant Arabidopsis thaliana (L.) Heynh. Arabidopsis plants were grown on agar containing a complete mineral complement and various concentrations of selenate and sulphate. The Se/S concentration ratio in the shoot ([Se](shoot)/[S](shoot)) showed a complex dependence on the ratio of selenate to sulphate concentration in the agar ([Se](agar)/[S](agar)). Increasing [S](agar) increased shoot fresh weight (FW) and [S](shoot), but decreased [Se](shoot). Increasing [Se](agar) increased both [Se](shoot) and [S](shoot), but reduced shoot FW. The reduction in shoot FW in the presence of Se was linearly related to the shoot Se/S concentration ratio. These data suggest (i) that Se and S enter Arabidopsis through multiple transport pathways with contrasting sulphate/selenate selectivities, whose activities vary between plants of contrasting nutritional status, (ii) that rhizosphere sulphate inhibits selenate uptake, (iii) that rhizosphere selenate promotes sulphate uptake, possibly by preventing the reduction in the abundance and/or activity of sulphate transporters by sulphate and/or its metabolites, and (iv) that Se toxicity occurs because Se and S compete for a biochemical process, such as assimilation into amino acids of essential proteins.

  19. Aluminium resistant, plant growth promoting bacteria induce overexpression of Aluminium stress related genes in Arabidopsis thaliana and increase the ginseng tolerance against Aluminium stress.

    Science.gov (United States)

    Farh, Mohamed El-Agamy; Kim, Yeon-Ju; Sukweenadhi, Johan; Singh, Priyanka; Yang, Deok-Chun

    2017-07-01

    Panax ginseng is an important cash crop in the Asian countries due to its pharmaceutical effects, however the plant is exposed to various abiotic stresses, lead to reduction of its quality. One of them is the Aluminum (Al) accumulation. Plant growth promoting bacteria which able to tolerate heavy metals has been considered as a new trend for supporting the growth of many crops in heavy metal occupied areas. In this study, twelve bacteria strains were isolated from rhizosphere of diseased Korean ginseng roots located in Gochang province, Republic of Korea and tested for their ability to grow in Al-embedded broth media. Out of them, four strains (Pseudomonas simiae N3, Pseudomonas fragi N8, Chryseobacterium polytrichastri N10, and Burkholderia ginsengiterrae N11-2) were able to grow. The strains could also show other plant growth promoting activities e.g. auxins and siderophores production and phosphate solubilization. P. simiae N3, C. polytrichastri N10, and B. ginsengiterrae N11-2 strains were able to support the growth of Arabidopsis thaliana stressed by Al while P. fragi N8 could not. Plants inoculated with P. simiae N3, C. polytrichastri N10, and B. ginsengiterrae N11-2 showed higher expression level of Al-stress related genes, AtAIP, AtALS3 and AtALMT1, compared to non-bacterized plants. Expression profiles of the genes reveal the induction of external mechanism of Al resistance by P. simiae N3 and B. ginsengiterrae N11-2 and internal mechanism by C. polytrichastri N10. Korean ginseng seedlings treated with these strains showed higher biomass, particularly the foliar part, higher chlorophyll content than non-bacterized Al-stressed seedlings. According to the present results, these strains can be used in the future for the cultivation of ginseng in Al-persisted locations. Copyright © 2017 Elsevier GmbH. All rights reserved.

  20. Knocking out ACR2 does not affect arsenic redox status in Arabidopsis thaliana: implications for as detoxification and accumulation in plants.

    Directory of Open Access Journals (Sweden)

    Wenju Liu

    Full Text Available Many plant species are able to reduce arsenate to arsenite efficiently, which is an important step allowing detoxification of As through either efflux of arsenite or complexation with thiol compounds. It has been suggested that this reduction is catalyzed by ACR2, a plant homologue of the yeast arsenate reductase ScACR2. Silencing of AtACR2 was reported to result in As hyperaccumulation in the shoots of Arabidopsis thaliana. However, no information of the in vivo As speciation has been reported. Here, we investigated the effect of AtACR2 knockout or overexpression on As speciation, arsenite efflux from roots and As accumulation in shoots. T-DNA insertion lines, overexpression lines and wild-type (WT plants were exposed to different concentrations of arsenate for different periods, and As speciation in plants and arsenite efflux were determined using HPLC-ICP-MS. There were no significant differences in As speciation between different lines, with arsenite accounting for >90% of the total extractable As in both roots and shoots. Arsenite efflux to the external medium represented on average 77% of the arsenate taken up during 6 h exposure, but there were no significant differences between WT and mutants or overexpression lines. Accumulation of As in the shoots was also unaffected by AtACR2 knockout or overexpression. Additionally, after exposure to arsenate, the yeast (Saccharomyces cerevisiae strain with ScACR2 deleted showed similar As speciation as the WT with arsenite-thiol complexes being the predominant species. Our results suggest the existence of multiple pathways of arsenate reduction in plants and yeast.

  1. Syntaxin of plant proteins SYP123 and SYP132 mediate root hair tip growth in Arabidopsis thaliana.

    Science.gov (United States)

    Ichikawa, Mie; Hirano, Tomoko; Enami, Kazuhiko; Fuselier, Taylor; Kato, Naohiro; Kwon, Chian; Voigt, Boris; Schulze-Lefert, Paul; Baluška, František; Sato, Masa H

    2014-04-01

    Root hairs are fast-growing tubular protrusions on root epidermal cells that play important roles in water and nutrient uptake in plants. The tip-focused polarized growth of root hairs is accomplished by the secretion of newly synthesized materials to the tip via the polarized membrane trafficking mechanism. Here, we report the function of two different types of plasma membrane (PM) Qa-SNAREs (soluble N-ethylmaleimide-sensitive factor attachment protein receptors), SYP123 and SYP132, in the growth of root hair in Arabidopsis. We found that SYP123, but not SYP132, localizes in the tip region of root hairs by recycling between the brefeldin A (BFA)-sensitive endosomes and the PM of the expanding tip in an F-actin-dependent manner. The vesicle-associated membrane proteins VAMP721/722/724 also exhibited tip-focused localization in root hairs and formed ternary SNARE complexes with both SYP123 and SYP132. These results demonstrate that SYP123 and SYP132 act in a coordinated fashion to mediate tip-focused membrane trafficking for root hair tip growth.

  2. Utilisation des mutations induites pour l'étude de l'embryogenèse chez le haricot Phaseolus vulgaris L. et deux plantes modèles Arabidopsis thaliana (L. Heynh. et Zea mays L.

    Directory of Open Access Journals (Sweden)

    Silué, S.

    2011-01-01

    Full Text Available Use of induced mutations in embryogenesis study in bean Phaseolus vulgaris L. and two model plants, Arabidopsis thaliana (L. Heynh. and Zea mays L.. Breeding of common bean, Phaseolus vulgaris L., through interspecific hybridizations with the species Phaseolus coccineus L. and Phaseolus polyanthus Greenm. as female parents leads to the abortion of immature embryos. Identification of genes required for embryo development could partly explain the abortion of hybrid embryos; induced mutations could thus be an alternative to identify key genes involved in Phaseolus embryogenesis. This paper is a review which shows a few examples of the use of induced mutations in the identification of essential genes for embryogenesis in two model plants, Arabidopsis thaliana (L. Heyhn. for dicots and Zea mays L. for monocots. In these two species, embryo development mutants have been isolated using insertional mutagenesis and chemical mutagenesis with Ethyl Methane Sulfonate (EMS. Arabidopsis embryo mutants are affected in apical-basal axis polarity, radial pattern and in post-embryonic stages. Some Arabidopsis embryo mutants are defected in auxin signalisation. In maize, defective kernel (dek mutants are affected in the embryo and the endosperm, while in embryo specific (emb mutants, only the embryo is affected. In common bean, plants deficient in seed development were isolated using EMS mutagenesis. Embryos inside the seeds fail to growth at different stages of development and show abnormalities mainly in the suspensor and the cotyledons.

  3. Characterisation of cuticular mutants in Arabidopsis thaliana

    OpenAIRE

    Faust, Andrea

    2006-01-01

    Plants are protected by the extracellular cuticle, which is made up of cutin, cutan and waxes. The cutin composition of a variety of plants has been known and models of the biosynthesis of cutin monomers exist but not many enzymes have been identified. It is generally accepted that a defect in the cuticle leads to an organ fusion phenotype. In the model plant A. thaliana many fusion mutants have been identified but the identification of genes involved have not lead to a complete picture of th...

  4. Arabidopsis thaliana as Bioindicator of Fungal VOCs in Indoor Air

    Science.gov (United States)

    Hung, Richard; Yin, Guohua; Klich, Maren A.; Grimm, Casey; Bennett, Joan W.

    2016-01-01

    In this paper, we demonstrate the ability of Arabidopsis thaliana to detect different mixtures of volatile organic compounds (VOCs) emitted by the common indoor fungus, Aspergillus versicolor, and demonstrate the potential usage of the plant as a bioindicator to monitor fungal VOCs in indoor air. We evaluated the volatile production of Aspergillus versicolor strains SRRC 108 (NRRL 3449) and SRRC 2559 (ATCC 32662) grown on nutrient rich fungal medium, and grown under conditions to mimic the substrate encountered in the built environment where fungi would typically grow indoors (moist wallboard and ceiling tiles). Using headspace solid phase microextraction/gas chromatography-mass spectrometry, we analyzed VOC profiles of the two strains. The most abundant compound produced by both strains on all three media was 1-octen-3-ol. Strain SRRC 2559 made several terpenes not detected from strain SRRC 108. Using a split-plate bioassay, we grew Arabidopsis thaliana in a shared atmosphere with VOCs from the two strains of Aspergillus versicolor grown on yeast extract sucrose medium. The VOCs emitted by SRRC 2559 had an adverse impact on seed germination and plant growth. Chemical standards of individual VOCs from the Aspergillus versicolor mixture (2-methyl-1-butanol, 3-methyl-1-butanol, 1-octen-3-ol, limonene, and β-farnesene), and β-caryophyllene were tested one by one in seed germination and vegetative plant growth assays. The most inhibitory compound to both seed germination and plant growth was 1-octen-3-ol. Our data suggest that Arabidopsis is a useful model for monitoring indoor air quality as it is sensitive to naturally emitted fungal volatile mixtures as well as to chemical standards of individual compounds, and it exhibits relatively quick concentration- and duration-dependent responses.

  5. Gibberellins control fruit patterning in Arabidopsis thaliana.

    Science.gov (United States)

    Arnaud, Nicolas; Girin, Thomas; Sorefan, Karim; Fuentes, Sara; Wood, Thomas A; Lawrenson, Tom; Sablowski, Robert; Østergaard, Lars

    2010-10-01

    The Arabidopsis basic helix-loop-helix (bHLH) proteins INDEHISCENT (IND) and ALCATRAZ (ALC) specify tissues required for fruit opening that have major roles in seed dispersal and plant domestication. Here, we show that synthesis of the phytohormone gibberellin is a direct and necessary target of IND, and that ALC interacts directly with DELLA repressors, which antagonize ALC function but are destabilized by gibberellin. Thus, the gibberellin/DELLA pathway has a key role in patterning the Arabidopsis fruit, and the interaction between DELLA and bHLH proteins, previously shown to connect gibberellin and light responses, is a versatile regulatory module also used in tissue patterning.

  6. Characterization of the snowy cotyledon 1 mutant of Arabidopsis thaliana: the impact of chloroplast elongation factor G on chloroplast development and plant vitality.

    Science.gov (United States)

    Albrecht, Verónica; Ingenfeld, Anke; Apel, Klaus

    2006-03-01

    During seedling development chloroplast formation marks the transition from heterotrophic to autotrophic growth. The development and activity of chloroplasts may differ in cotyledons that initially serve as a storage organ and true leaves whose primary function is photosynthesis. A genetic screen was used for the identification of genes that affect selectively chloroplast function in cotyledons of Arabidopsis thaliana. Several mutants exhibiting pale cotyledons and green true leaves were isolated and dubbed snowy cotyledon (sco). One of the mutants, sco1, was characterized in more detail. The mutated gene was identified using map-based cloning. The mutant contains a point mutation in a gene encoding the chloroplast elongation factor G, leading to an amino acid exchange within the predicted 70S ribosome-binding domain. The mutation results in a delay in the onset of germination. At this early developmental stage embryos still contain undifferentiated proplastids, whose proper function seems necessary for seed germination. In light-grown sco1 seedlings the greening of cotyledons is severely impaired, whereas the following true leaves develop normally as in wild-type plants. Despite this apparent similarity of chloroplast development in true leaves of mutant and wild-type plants various aspects of mature plant development are also affected by the sco1 mutation such as the onset of flowering, the growth rate, and seed production. The onset of senescence in the mutant and the wild-type plants occurs, however, at the same time, suggesting that in the mutant this particular developmental step does not seem to suffer from reduced protein translation efficiency in chloroplasts.

  7. Redox Impact on Starch Biosynthetic Enzymes in Arabidopsis thaliana

    DEFF Research Database (Denmark)

    Skryhan, Katsiaryna

    Summary The thesis provides new insight into the influence of the plant cell redox state on the transient starch metabolism in Arabidopsis thaliana with a focus on starch biosynthetic enzymes. Two main hypotheses forms the basis of this thesis: 1) photosynthesis and starch metabolism are coordina......Summary The thesis provides new insight into the influence of the plant cell redox state on the transient starch metabolism in Arabidopsis thaliana with a focus on starch biosynthetic enzymes. Two main hypotheses forms the basis of this thesis: 1) photosynthesis and starch metabolism...... are coordinated by the redox state of the cell via post-translational modification of the starch metabolic enzymes containing redox active cysteine residues and these cysteine residues became cross-linked upon oxidation providing a conformational change leading to activity loss; 2) cysteine residues...... of chloroplast enzymes can play a role not only in enzyme activity and redox sensitivity but also in protein folding and stability upon oxidation. Several redox sensitive enzymes identified in this study can serve as potential targets to control the carbon flux to and from starch during the day and night...

  8. HAL1 mediate salt adaptation in Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The yeast HAL1 gene was introduced into Arabidopsis thaliana by Agrobacterium tumefaciens-mediated transformation with vacuum infiltration under the control of CaMV 35S promoter.Thirty-three individual kanamycin resistant plants were obtained from 75,000 seeds.Southern blotting analysis indicated that HAL1 gene had been integrated into all of the transgenic plants' genomes.The copy number of HAL1 gene in transgenic plants was mostly 1 to 3 by Southern analysis.Phenotypes of transgenic plants have no differences with wild type plants.Several samples of transformants were self-pollinated,and progenies from transformed and non-transformed plants(controls)were evaluated for salt tolerance and gene expression.Measurement of concentrations of intracellular K+ and Na+ showed that transgenic lines were able to retain less Na+ than that of the control under salt stress.Results from different tests indicated the expression of HAL1 gene promotes a higher level of salt tolerance in vivo in the transgenic Arabidopsis plants.

  9. Inverse polymerase chain reaction for rapid gene isolation in Arabidopsis thaliana insertion mutants

    NARCIS (Netherlands)

    Vanderhaeghen, R.; Scheres, B.J.G.; Montagu, M. van; Lijsebetten, M. van

    1992-01-01

    Recently, many mutants have been isolated in the model plant Arabidopsis thaliana by the insertion of the Agrobacterium tumefaciens T-DNA into the plant genome. Instead of applying Southern analysis on these insertion mutants and to avoid the construction of mutant- derived genomic libraries, we pro

  10. Alleviation of Copper Toxicity in Arabidopsis Thaliana and Zinnia Elegans by Silicon Addition

    Science.gov (United States)

    While the role of silicon in plants has been studied for over 150 years, and this element can mitigate the effects of certain heavy metals, its role in Cu metabolism is unclear. Therefore, the role of Si in plant response to Cu stress was investigated in Arabidopsis thaliana L. (Heyn) and Zinnia el...

  11. Exploring Arabidopsis thaliana Root Endophytes via Single-Cell Genomics

    Energy Technology Data Exchange (ETDEWEB)

    Lundberg, Derek; Woyke, Tanja; Tringe, Susannah; Dangl, Jeff

    2014-03-19

    Land plants grow in association with microbial communities both on their surfaces and inside the plant (endophytes). The relationships between microbes and their host can vary from pathogenic to mutualistic. Colonization of the endophyte compartment occurs in the presence of a sophisticated plant immune system, implying finely tuned discrimination of pathogens from mutualists and commensals. Despite the importance of the microbiome to the plant, relatively little is known about the specific interactions between plants and microbes, especially in the case of endophytes. The vast majority of microbes have not been grown in the lab, and thus one of the few ways of studying them is by examining their DNA. Although metagenomics is a powerful tool for examining microbial communities, its application to endophyte samples is technically difficult due to the presence of large amounts of host plant DNA in the sample. One method to address these difficulties is single-cell genomics where a single microbial cell is isolated from a sample, lysed, and its genome amplified by multiple displacement amplification (MDA) to produce enough DNA for genome sequencing. This produces a single-cell amplified genome (SAG). We have applied this technology to study the endophytic microbes in Arabidopsis thaliana roots. Extensive 16S gene profiling of the microbial communities in the roots of multiple inbred A. thaliana strains has identified 164 OTUs as being significantly enriched in all the root endophyte samples compared to their presence in bulk soil.

  12. Gravity perception and gravitropic response of inflorescence stems in Arabidopsis thaliana

    Science.gov (United States)

    Fukaki, H.; Tasaka, M.

    1999-01-01

    Shoots of higher plants exhibit negative gravitropism. However, little is known about the site of gravity perception in shoots and the molecular mechanisms of shoot gravitropic responses. Our recent analysis using shoot gravitropism1(sgr1)/scarecrow(scr) and sgr7/short-root (shr) mutants in Arabidopsis thaliana indicated that the endodermis is essential for shoot gravitropism and strongly suggested that the endodermis functions as the gravity-sensing cell layer in dicotyledonous plant shoots. In this paper, we present our recent analysis and model of gravity perception and gravitropic response of inflorescence stems in Arabidopsis thaliana.

  13. Ecology of Arabidopsis thaliana : local adaptation and interaction with herbivores

    NARCIS (Netherlands)

    Mosleh Arany, A.

    2006-01-01

    As first step the impact of herbivory and abiotic factors on population dynamics of Arabidopsis thaliana were studied. Ceutorhynchus atomus and C. contractus were identified as the major insect herbivores on A. thaliana population, reducing seed production by more than 40%. Mortality from February t

  14. Multimodal nonlinear imaging of arabidopsis thaliana root cell

    Science.gov (United States)

    Jang, Bumjoon; Lee, Sung-Ho; Woo, Sooah; Park, Jong-Hyun; Lee, Myeong Min; Park, Seung-Han

    2017-07-01

    Nonlinear optical microscopy has enabled the possibility to explore inside the living organisms. It utilizes ultrashort laser pulse with long wavelength (greater than 800nm). Ultrashort pulse produces high peak power to induce nonlinear optical phenomenon such as two-photon excitation fluorescence (TPEF) and harmonic generations in the medium while maintaining relatively low average energy pre area. In plant developmental biology, confocal microscopy is widely used in plant cell imaging after the development of biological fluorescence labels in mid-1990s. However, fluorescence labeling itself affects the sample and the sample deviates from intact condition especially when labelling the entire cell. In this work, we report the dynamic images of Arabidopsis thaliana root cells. This demonstrates the multimodal nonlinear optical microscopy is an effective tool for long-term plant cell imaging.

  15. CB5C affects the glucosinolate profile in Arabidopsis thaliana

    DEFF Research Database (Denmark)

    Vik, Daniel; Crocoll, Christoph; Andersen, Tonni Grube

    2016-01-01

    Cytochrome b5 (CB5) proteins are small heme-binding proteins, that influence cytochrome P450 activity. While only one CB5 isoform is found in mammals, higher plants have several isoforms of these proteins. The roles of the many CB5 isoforms in plants remain unknown. We hypothesized that CB5...... proteins support the cytochrome P450 enzymes of plant specialized metabolism and found CB5C from Arabidopsis thaliana to co-express with glucosinolate biosynthetic genes. We characterized the glucosinolate profiles of two T-DNA insertion mutants of CB5C, and found that long-chained aliphatic glucosinolates...... were reduced in one of the mutant lines - a phenotype that was exaggerated upon methyl-jasmonate treatment. These results support the hypothesis, that CB5C influences glucosinolate biosynthesis, however, the mode of action remains unknown. Furthermore, the mutants differed in their biomass response...

  16. Protists are an integral part of the Arabidopsis thaliana microbiome.

    Science.gov (United States)

    Sapp, Melanie; Ploch, Sebastian; Fiore-Donno, Anna Maria; Bonkowski, Michael; Rose, Laura E

    2017-10-02

    Although protists occupy a vast range of habitats and are known to interact with plants among other things via disease suppression, competition or growth stimulation, their contributions to the "phytobiome" are not well described. To contribute to a more comprehensive picture of the plant holobiont, we examined cercozoan and oomycete taxa living in association with the model plant Arabidopsis thaliana grown in two different soils. Soil, roots, leaves and wooden toothpicks were analyzed before and after surface sterilization. Cercozoa were identified using 18S rRNA gene metabarcoding, whereas the Internal Transcribed Spacer (ITS1) was used to determine oomycetes. Subsequent analyses revealed strong spatial structuring of protist communities between compartments, although oomycetes appeared more specialized than Cercozoa. With regards to oomycetes, only members of the Peronosporales and taxa belonging to the genus Globisporangium were identified as shared members of the A. thaliana microbiome. This also applied to cercozoan taxa belonging to the Glissomonadida and Cercomonadida. We identified a strong influence by edaphic factors on the rhizosphere, but not for the phyllosphere. Distinct differences of Cercozoa found preferably in wood or fresh plant material imply specific niche adaptations. Our results highlight the importance of micro-eukaryotes for the plant holobiont. This article is protected by copyright. All rights reserved. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  17. Metabolic Profiling of Intact Arabidopsis thaliana Leaves during Circadian Cycle Using 1H High Resolution Magic Angle Spinning NMR.

    NARCIS (Netherlands)

    Augustijn, D.; Roy, U.; Schadewijk, van R.; Groot, de H.J.M.; Matysik, A.

    2016-01-01

    Arabidopsis thaliana is the most widely used model organism for research in plant biology. While significant advances in understanding plant growth and development have been made by focusing on the molecular genetics of Arabidopsis, extracting and understanding the functional framework of metabolism

  18. Photochemistry of PSII in CYP38 Arabidopsis thaliana Deletion Mutant

    Directory of Open Access Journals (Sweden)

    Hrvoje Lepeduš

    2009-01-01

    Full Text Available Chloroplast protein CYP38 is a cyclophilin-like peptidyl-prolyl cis-trans isomerase involved in photosystem II (PSII assembly. It also serves as a regulator of thylakoid protein phosphatase. In this work the efficiency of PSII in CYP38 deficient Arabidopsis thaliana M13 plants has been analyzed by measuring in vivo chlorophyll a (Chl a fluorescence transient (OJIP test. Significant differences in overall photosynthetic performance (PIABS, absorption (ABS/RC, trapping (TRo/RC, electron transport (ETo/RC, and dissipation (DIo/RC were observed between A. thaliana M13 and the wild type (WT plants. Increased Chl a and Chl b levels, as well as decreased Chl a/Chl b ratio were measured in M13 plants, indicating the adjustment of PSII antenna for increasing light absorption capability. Based on the obtained results, it can be concluded that the deficiency in CYP38 protein leads to impaired function of PSII due to the conversion of a certain fraction of active reaction centres to dissipative ones. This leads to a decrease in overall photosynthetic performance (PIABS in M13 plants. Such effect was due to lowering of TRo/DIo parameter, which was influenced mostly by significant increases in energy dissipation (DIo/RC and in trapping of electrons (TRo/RC per active reaction centre.

  19. Multiple reference genomes and transcriptomes for Arabidopsis thaliana

    KAUST Repository

    Gan, Xiangchao

    2011-08-28

    Genetic differences between Arabidopsis thaliana accessions underlie the plants extensive phenotypic variation, and until now these have been interpreted largely in the context of the annotated reference accession Col-0. Here we report the sequencing, assembly and annotation of the genomes of 18 natural A. thaliana accessions, and their transcriptomes. When assessed on the basis of the reference annotation, one-third of protein-coding genes are predicted to be disrupted in at least one accession. However, re-annotation of each genome revealed that alternative gene models often restore coding potential. Gene expression in seedlings differed for nearly half of expressed genes and was frequently associated with cis variants within 5 kilobases, as were intron retention alternative splicing events. Sequence and expression variation is most pronounced in genes that respond to the biotic environment. Our data further promote evolutionary and functional studies in A. thaliana, especially the MAGIC genetic reference population descended from these accessions. ©2011 Macmillan Publishers Limited. All rights reserved.

  20. Gravitropism in leaves of Arabidopsis thaliana (L.) Heynh.

    Science.gov (United States)

    Mano, Eriko; Horiguchi, Gorou; Tsukaya, Hirokazu

    2006-02-01

    In higher plants, stems and roots show negative and positive gravitropism, respectively. However, current knowledge on the graviresponse of leaves is lacking. In this study, we analyzed the positioning and movement of rosette leaves of Arabidopsis thaliana under light and dark conditions. We found that the radial positioning of rosette leaves was not affected by the direction of gravity under continuous white light. In contrast, when plants were shifted to darkness, the leaves moved upwards, suggesting negative gravitropism. Analysis of the phosphoglucomutase and shoot gravitropism 2-1 mutants revealed that the sedimenting amyloplasts in the leaf petiole are important for gravity perception, as is the case in stems and roots. In addition, our detailed physiological analyses revealed a unique feature of leaf movement after the shift to darkness, i.e. movement could be divided into negative gravitropism and nastic movement. The orientation of rosette leaves is ascribed to a combination of these movements.

  1. Cell wall proteome analysis of Arabidopsis thaliana mature stems.

    Science.gov (United States)

    Duruflé, Harold; Clemente, Hélène San; Balliau, Thierry; Zivy, Michel; Dunand, Christophe; Jamet, Elisabeth

    2017-04-01

    Plant stems carry flowers necessary for species propagation and need to be adapted to mechanical disturbance and environmental factors. The stem cell walls are different from other organs and can modify their rigidity or viscoelastic properties for the integrity and the robustness required to withstand mechanical impacts and environmental stresses. Plant cell wall is composed of complex polysaccharide networks also containing cell wall proteins (CWPs) crucial to perceive and limit the environmental effects. The CWPs are fundamental players in cell wall remodeling processes, and today, only 86 have been identified from the mature stems of the model plant Arabidopsis thaliana. With a destructive method, this study has enlarged its coverage to 302 CWPs. This new proteome is mainly composed of 27.5% proteins acting on polysaccharides, 16% proteases, 11.6% oxido-reductases, 11% possibly related to lipid metabolism and 11% of proteins with interacting domains with proteins or polysaccharides. Compared to stem cell wall proteomes already available (Brachypodium distachyon, Sacharum officinarum, Linum usitatissimum, Medicago sativa), that of A. thaliana stems has a higher proportion of proteins acting on polysaccharides and of proteases, but a lower proportion of oxido-reductases. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Differentiation between MAMP Triggered Defenses in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Madlen Vetter

    2016-06-01

    Full Text Available A first line of defense against pathogen attack for both plants and animals involves the detection of microbe-associated molecular patterns (MAMPs, followed by the induction of a complex immune response. Plants, like animals, encode several receptors that recognize different MAMPs. While these receptors are thought to function largely redundantly, the physiological responses to different MAMPs can differ in detail. Responses to MAMP exposure evolve quantitatively in natural populations of Arabidopsis thaliana, perhaps in response to environment specific differences in microbial threat. Here, we sought to determine the extent to which the detection of two canonical MAMPs were evolving redundantly or distinctly within natural populations. Our results reveal negligible correlation in plant growth responses between the bacterial MAMPs EF-Tu and flagellin. Further investigation of the genetic bases of differences in seedling growth inhibition and validation of 11 candidate genes reveal substantial differences in the genetic loci that underlie variation in response to these two MAMPs. Our results indicate that natural variation in MAMP recognition is largely MAMP-specific, indicating an ability to differentially tailor responses to EF-Tu and flagellin in A. thaliana populations.

  3. Numerical and structural chromosome aberrations in cauliflower (Brassica oleracea var. botrytis) and Arabidopsis thaliana

    NARCIS (Netherlands)

    Ji, X.

    2014-01-01

    Numerical and structural chromosome aberrations in cauliflower (Brassica oleracea var. botrytis) and Arabidopsis thaliana. I studied numerical and structural chromosome aberrations in cauliflower (Brassica oleracea var. botrytis) and Arabidopsis thaliana. The large genomic changes are important for

  4. Numerical and structural chromosome aberrations in cauliflower (Brassica oleracea var. botrytis) and Arabidopsis thaliana

    NARCIS (Netherlands)

    Ji, X.

    2014-01-01

    Numerical and structural chromosome aberrations in cauliflower (Brassica oleracea var. botrytis) and Arabidopsis thaliana. I studied numerical and structural chromosome aberrations in cauliflower (Brassica oleracea var. botrytis) and Arabidopsis thaliana. The large genomic changes are important for

  5. Molecular characterization of the submergence response of Arabidopsis thaliana ecotype Columbia

    DEFF Research Database (Denmark)

    Lee, S.C.; Mustroph, A.; Sasidaharan, R.

    2011-01-01

    A detailed description of the molecular response of Arabidopsis thaliana to submergence can aid the identification of genes that are critical to flooding survival. • Rosette-stage plants were fully submerged in complete darkness and shoot and root tissue was harvested separately after the O2...

  6. Genetic analysis of induced systemic resistance in Arabidopsis thaliana: association between induced and basal resistance

    NARCIS (Netherlands)

    Ton, J.; Pieterse, C.M.J.; Loon, L.C. van

    1998-01-01

    Selected nonpathogenic rhizobacteria are able to elicit induced systemic resistance (ISR) in plants. Different ecotypes of Arabidopsis thaliana were screened for expression of ISR against infection by Pseudomonas syringae pv. tomato, after treatment of the roots with the nonpathogenic P. fluorescens

  7. A class V chitinase from Arabidopsis thaliana: gene responses, enzymatic properties, and crystallographic analysis

    DEFF Research Database (Denmark)

    Ohnuma, Takayuki; Numata, Tomoyuki; Osawa, Takuo

    2011-01-01

    Expression of a class V chitinase gene (At4g19810, AtChiC) in Arabidopsis thaliana was examined by quantitative real-time PCR and by analyzing microarray data available at Genevestigator. The gene expression was induced by the plant stress-related hormones abscisic acid (ABA) and jasmonic acid (J...

  8. Study of natural variation for Zn deficiency tolerance in Arabidopsis thaliana

    NARCIS (Netherlands)

    Campos, A.C.A.L.

    2015-01-01

    English summary Zinc is an important structural component and co-factor of proteins in all living organisms. The model plant species for genetic and molecular studies, Arabidopsis thaliana, expresses more than 2,000 proteins with one or more Zn binding domains. Low Zn availability

  9. Natural variation in flowering time among populations of the annual crucifer Arabidopsis thaliana

    NARCIS (Netherlands)

    Hammad, I.; Van Tienderen, P.H.

    1997-01-01

    Genetic variation in flowering time was studied in four natural populations of Arabidopsis thaliana, using greenhouse experiments. Two populations from ruderal sites flowered early, two others from river dykes late. However, the late flowering plants flowered almost as early as the others after cold

  10. Study of natural variation for Zn deficiency tolerance in Arabidopsis thaliana

    NARCIS (Netherlands)

    Campos, A.C.A.L.

    2015-01-01

    English summary Zinc is an important structural component and co-factor of proteins in all living organisms. The model plant species for genetic and molecular studies, Arabidopsis thaliana, expresses more than 2,000 proteins with one or more Zn binding domains. Low Zn availability i

  11. Genome-wide computational function prediction of Arabidopsis thaliana proteins by integration of multiple data sources

    NARCIS (Netherlands)

    Kourmpetis, Y.I.A.; Dijk, van A.D.J.; Ham, van R.C.H.J.; Braak, ter C.J.F.

    2011-01-01

    Although Arabidopsis thaliana is the best studied plant species, the biological role of one third of its proteins is still unknown. We developed a probabilistic protein function prediction method that integrates information from sequences, protein-protein interactions and gene expression. The method

  12. The genetics of some planthormones and photoreceptors in Arabidopsis thaliana (L.) Heynh

    NARCIS (Netherlands)

    Koornneef, M.

    1982-01-01

    This thesis describes the isolation and characterization in Arabidopsis thaliana (L.) Heynh. of induced mutants, deficient for gibberellins (GA's), abscisic acid (ABA) and photoreceptors.These compounds are known to regulate various facets of plant growth and differentiation, so mutants lacking one

  13. Microgravity effects on Arabidopsis thaliana energy pool

    Science.gov (United States)

    Dobrota, C.; Piso, M. I.; Banciu, H.; Keul, A.

    The flexibility of plant bioenergetics helps plants to acclimate to environmental stresses Our work is focused on standard free energy changes for PPi and ATP hydrolysis in order to assess the relative importance of PPi versus ATP as an energy donor in the plant cytosol of Arabidopsis plants exposed to microgravity The results indicated that PPi would be particularly favored as a phosphoryl donor relative to ATP under cytosolic conditions known to accompany stresses Recent researches showed that besides its functions inside the cell ATP may be released to the extracellular milieu where it functions as the primary signaling molecule of a diverse range of physiological processes It seems that extracellular ATP is essential for maintaining plant cell viability We intend to study how the production and the release of ATP is influenced by the microgravity References begin enumerate item Chivasaa S Bongani K Ndimbab W Simonc J Lindseyc K and Slabasc A 2005 Extracellular ATP Functions as an Endogenous External Metabolite Regulating Plant Cell Viability The Plant Cell 17 3019-3034 item Palma D A Blumwald E and Plaxton W C 2000 Upregulation of vacuolar H -translocating pyrophosphatase by phosphate starvation of Brassica napus rapeseed suspension cell cultures FEBS Letters 486 155-158 item Plaxton W C 2004 Plant response to stress Biochemical adaptations to phosphate deficiency In R Goodman ed Encyclopedia of Plant and Crop Science Marcel Dekker Inc N Y end enumerate

  14. Control of Cultivable IAA-Producing Bacteria by the Plant Arabidopsis thaliana and the Earthworm Aporrectodea caliginosa

    Directory of Open Access Journals (Sweden)

    Ruben Puga-Freitas

    2012-01-01

    Full Text Available Some soil microorganisms are involved in the complex interactions with plants and earthworms, through the production of indole acetic acid (IAA which modifies plant growth and development. In a factorial experiment testing the impact of the presence/absence of plants and earthworms on IAA production by cultivable bacteria, we observed that plants were decreasing IAA production of 43%, whereas earthworms were increasing it of 46%. In the presence of both plant and earthworms, IAA production was as low as in the presence of plant control, showing that plants influence on IAA production by microorganisms prevails on earthworm influence. We discuss functional reasons which could explain this result.

  15. Determination of Arabidopsis thaliana telomere length by PCR.

    Science.gov (United States)

    Vaquero-Sedas, María I; Vega-Palas, Miguel A

    2014-07-02

    In humans, telomere length studies have acquired great relevance because the length of telomeres has been related to natural processes like disease, aging and cancer. However, very little is known about the influence of telomere length on the biology of wild type plants. The length of plant telomeres has been usually studied by Terminal Restriction Fragment (TRF) analyses. This technique requires high amounts of tissue, including multiple cell types, which might be the reason why very little is known about the influence of telomere length on plant natural processes. In contrast, many of the human telomere length studies have focused on homogenous cell populations. Most of these studies have been performed by PCR, using telomeric degenerated primers, which allow the determination of telomere length from small amounts of human cells. Here, we have adapted the human PCR procedure to analyze the length of Arabidopsis thaliana telomeres. This PCR approach will facilitate the analysis of telomere length from low amounts of tissue. We have used it to determine that CG and non CG DNA methylation positively regulates Arabidopsis telomere length.

  16. Molecule mechanism of stem cells in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Wenjin Zhang

    2014-01-01

    Full Text Available Plants possess the ability to continually produce new tissues and organs throughout their life. Unlike animals, plants are exposed to extreme variations in environmental conditions over the course of their lives. The vitality of plants is so powerful that they can survive several hundreds of years or even more making it an amazing miracle that comes from plant stem cells. The stem cells continue to divide to renew themselves and provide cells for the formation of leaves, stems, and flowers. Stem cells are not only quiescent but also immortal, pluripotent and homeostatic. Stem cells are the magic cells that repair tissues and regenerate organs. During the past decade, scholars around the world have paid more and more attention toward plant stem cells. At present, the major challenge is in relating molecule action mechanism to root apical meristem, shoot apical meristem and vascular system. The coordination between stem cells maintenance and differentiation is critical for normal plant growth and development. Elements such as phytohormones, transcription factors and some other known or unknown genes cooperate to balance this process. In this review, Arabidopsis thaliana as a pioneer system, we highlight recent developments in molecule modulating, illustrating how plant stem cells generate new mechanistic insights into the regulation of plants growth and development.

  17. The molecular population genetics of shoot development in Arabidopsis thaliana.

    Science.gov (United States)

    Shepard, Kristen A

    2007-01-01

    Studies in Arabidopsis thaliana have provided us with a wealth of information about the genetic pathways that regulate plant morphogenesis. This developmental genetic treasure trove represents a fantastic resource for researchers interested in the microevolution of development. Several laboratories have begun using molecular population genetic analyses to investigate the evolutionary forces that act upon loci that regulate shoot morphogenesis. Much of this work has focused on coding sequence variation in transcription factors; however, recent studies have explored sequence variation in other types of proteins and in promoter regions. Several genes that regulate shoot development contain signatures of selective sweeps associated with positive selection or harbor putative balanced polymorphisms in coding and noncoding sequences. Other regulatory genes appear to be evolving neutrally, but have accumulated potentially deleterious replacement polymorphisms.

  18. Epigenomic Diversity in a Global Collection of Arabidopsis thaliana Accessions.

    Science.gov (United States)

    Kawakatsu, Taiji; Huang, Shao-Shan Carol; Jupe, Florian; Sasaki, Eriko; Schmitz, Robert J; Urich, Mark A; Castanon, Rosa; Nery, Joseph R; Barragan, Cesar; He, Yupeng; Chen, Huaming; Dubin, Manu; Lee, Cheng-Ruei; Wang, Congmao; Bemm, Felix; Becker, Claude; O'Neil, Ryan; O'Malley, Ronan C; Quarless, Danjuma X; Schork, Nicholas J; Weigel, Detlef; Nordborg, Magnus; Ecker, Joseph R

    2016-07-14

    The epigenome orchestrates genome accessibility, functionality, and three-dimensional structure. Because epigenetic variation can impact transcription and thus phenotypes, it may contribute to adaptation. Here, we report 1,107 high-quality single-base resolution methylomes and 1,203 transcriptomes from the 1001 Genomes collection of Arabidopsis thaliana. Although the genetic basis of methylation variation is highly complex, geographic origin is a major predictor of genome-wide DNA methylation levels and of altered gene expression caused by epialleles. Comparison to cistrome and epicistrome datasets identifies associations between transcription factor binding sites, methylation, nucleotide variation, and co-expression modules. Physical maps for nine of the most diverse genomes reveal how transposons and other structural variants shape the epigenome, with dramatic effects on immunity genes. The 1001 Epigenomes Project provides a comprehensive resource for understanding how variation in DNA methylation contributes to molecular and non-molecular phenotypes in natural populations of the most studied model plant.

  19. Redox Impact on Starch Biosynthetic Enzymes in Arabidopsis thaliana

    DEFF Research Database (Denmark)

    Skryhan, Katsiaryna

    Summary The thesis provides new insight into the influence of the plant cell redox state on the transient starch metabolism in Arabidopsis thaliana with a focus on starch biosynthetic enzymes. Two main hypotheses forms the basis of this thesis: 1) photosynthesis and starch metabolism...... are coordinated by the redox state of the cell via post-translational modification of the starch metabolic enzymes containing redox active cysteine residues and these cysteine residues became cross-linked upon oxidation providing a conformational change leading to activity loss; 2) cysteine residues...... of chloroplast enzymes can play a role not only in enzyme activity and redox sensitivity but also in protein folding and stability upon oxidation. Several redox sensitive enzymes identified in this study can serve as potential targets to control the carbon flux to and from starch during the day and night...

  20. Pollen and ovule development in Arabidopsis thaliana under spaceflight conditions.

    Science.gov (United States)

    Kuang, A; Musgrave, M E; Matthews, S W; Cummins, D B; Tucker, S C

    1995-05-01

    The development of pollen and ovules in Arabidopsis thaliana on the space shuttle 'Endeavour' (STS-54) was investigated. Plants were grown on nutrient agar for 14 days prior to loading into closed plant growth chambers that received light and temperature control inside the Plant Growth Unit flight hardware on the shuttle middeck. After 6 days in spaceflight the plants were retrieved and immediately dissected and processed for light and electron microscope observation. Reproductive development aborted at an early stage. Pistils were collapsed and ovules inside were seen to he empty. No viable pollen was observed from STS-54 plants; young microspores were deformed and empty. At a late stage, the cytoplasm of the pollen contracted and became disorganized, but the pollen wall developed and the exine appeared normal. The tapetum in the flight flowers degenerated at early stages. Ovules from STS-54 flight plants stopped growing and the integuments and nucellus collapsed and degenerated. The megasporocytes appeared abnormal and rarely underwent meiosis. Apparently they enlarged, or occasionally produced a dyad or tetrad, to assume the form of a female gametophyte with the single nucleus located in an egglike cell that lacks a cell wall. Synergids, polar nuclei, and antipodals were not observed. The results demonstrate the types of lesions occurring in plant reproductive material under spaceflight conditions.

  1. Comparison of the chloroplast peroxidase system in the chlorophyte Chlamydomonas reinhardtii, the bryophyte Physcomitrella patens, the lycophyte Selaginella moellendorffii and the seed plant Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Baier Margarete

    2010-06-01

    Full Text Available Abstract Background Oxygenic photosynthesis is accompanied by the formation of reactive oxygen species (ROS, which damage proteins, lipids, DNA and finally limit plant yield. The enzymes of the chloroplast antioxidant system are exclusively nuclear encoded. During evolution, plastid and mitochondrial genes were post-endosymbiotically transferred to the nucleus, adapted for eukaryotic gene expression and post-translational protein targeting and supplemented with genes of eukaryotic origin. Results Here, the genomes of the green alga Chlamydomonas reinhardtii, the moss Physcomitrella patens, the lycophyte Selaginella moellendorffii and the seed plant Arabidopsis thaliana were screened for ORFs encoding chloroplast peroxidases. The identified genes were compared for their amino acid sequence similarities and gene structures. Stromal and thylakoid-bound ascorbate peroxidases (APx share common splice sites demonstrating that they evolved from a common ancestral gene. In contrast to most cormophytes, our results predict that chloroplast APx activity is restricted to the stroma in Chlamydomonas and to thylakoids in Physcomitrella. The moss gene is of retrotransposonal origin. The exon-intron-structures of 2CP genes differ between chlorophytes and streptophytes indicating an independent evolution. According to amino acid sequence characteristics only the A-isoform of Chlamydomonas 2CP may be functionally equivalent to streptophyte 2CP, while the weakly expressed B- and C-isoforms show chlorophyte specific surfaces and amino acid sequence characteristics. The amino acid sequences of chloroplast PrxII are widely conserved between the investigated species. In the analyzed streptophytes, the genes are unspliced, but accumulated four introns in Chlamydomonas. A conserved splice site indicates also a common origin of chlorobiont PrxQ. The similarity of splice sites also demonstrates that streptophyte glutathione peroxidases (GPx are of common origin. Besides

  2. A systemic increase in the recombination frequency upon local infection of Arabidopsis thaliana plants with oilseed rape mosaic virus depends on plant age, the initial inoculum concentration and the time for virus replication.

    Science.gov (United States)

    Yao, Youli; Kathiria, Palak; Kovalchuk, Igor

    2013-01-01

    In the past, we showed that local infection of tobacco leaves with either tobacco mosaic virus or oilseed rape mosaic virus (ORMV) resulted in a systemic increase in the homologous recombination frequency (HRF). Later on, we showed that a similar phenomenon occurs in Arabidopsis thaliana plants infected with ORMV. Here, we tested whether the time of removing the infected leaves as well as viral titer have any effect on the degree of changes in HRF in systemic tissues. An increase in HRF in systemic non-infected tissues was more pronounced when the infected leaves were detached from the infected plants at 60-96 h post-infection, rather than at earlier time. Next, we found that exposure to higher concentrations of inoculum was much more efficient in triggering an increase in HRF than exposure to lower concentrations. Finally, we showed that older plants exhibited a higher increase in HRF than younger plants. We found that an increase in genome instability in systemic tissues of locally infected plants depends on plant age, the concentration of initial inoculums and the time of viral replication.

  3. A systemic increase in the recombination frequency upon local infection of Arabidopsis thaliana plants with oilseed rape mosaic virus depends on plant age, the initial inoculum concentration and the time for virus replication

    Directory of Open Access Journals (Sweden)

    Youli eYao

    2013-03-01

    Full Text Available In the past, we showed that local infection of tobacco leaves with either Tobacco mosaic virus (TMV or Oilseed rape mosaic virus (ORMV resulted in a systemic increase in the homologous recombination frequency (HRF. Later on, we showed that a similar phenomenon occurs in Arabidopsis thaliana plants infected with ORMV. Here, we tested whether the time of removing the infected leaves as well as viral titer have any effect on the degree of changes in HRF in systemic tissues. An increase in HRF in systemic non-infected tissues was more pronounced when the infected leaves were detached from the infected plants at 60-96 hours post infection, rather than at earlier time. Next, we found that exposure to higher concentrations of inoculum was much more efficient in triggering an increase in HRF than exposure to lower concentrations. Finally, we showed that older plants exhibited a higher increase in HRF than younger plants. We found that an increase in genome instability in systemic tissues of locally infected plants depends on plant age, the concentration of initial inoculums and the time of viral replication.

  4. Mechanisms guiding Polycomb activities during gene silencing in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Chongsheng eHe

    2013-11-01

    Full Text Available Polycomb group (PcG proteins act in an evolutionarily conserved epigenetic pathway that regulates chromatin structures in plants and animals, repressing many developmentally important genes by modifying histones. PcG proteins can form at least two multiprotein complexes: Polycomb repressive complexes 1 and 2 (PRC1 and PRC2, respectively. The functions of Arabidopsis thaliana PRCs have been characterized in multiple stages of development and have diverse roles in response to environmental stimuli. Recently, the mechanism that precisely regulates Arabidopsis PcG activity was extensively studied. In this review, we summarize recent discoveries in the regulations of PcG at the three different layers: the recruitment of PRCs to specific target loci, the polyubiquitination and degradation of PRC2, and the antagonism of PRC2 activity by the Trithorax group proteins. Current knowledge indicates that the powerful activity of the PcG pathway is strictly controlled for specific silencing of target genes during plant development and in response to environmental stimuli.

  5. Ecological succession and stochastic variation in the assembly of Arabidopsis thaliana phyllosphere communities.

    OpenAIRE

    Maignien, Loïs; Deforce, Emelia A; Chafee, Meghan E.; Eren, A. Murat; Sheri L Simmons

    2014-01-01

    International audience; Bacteria living on the aerial parts of plants (the phyllosphere) are globally abundant and ecologically significant communities and can have significant effects on their plant hosts. Despite their importance, little is known about the ecological processes that drive phyllosphere dynamics. Here, we describe the development of phyllosphere bacterial communities over time on the model plant Arabidopsis thaliana in a controlled greenhouse environment. We used a large numbe...

  6. Phosphate uptake and allocation – a closer look at Arabidopsis thaliana L. and Oryza sativa L.

    Directory of Open Access Journals (Sweden)

    Ewa Młodzińska

    2016-08-01

    Full Text Available This year marks the 20th anniversary of the discovery and characterization of the two Arabidopsis PHT1 genes encoding the phosphate transporter in Arabidopsis thaliana. So far, multiple inorganic phosphate (Pi transporters have been described, and the molecular basis of Pi acquisition by plants has been well characterized. These genes are involved in Pi acquisition, allocation and/or signal transduction. This review summarizes how Pi is taken up by the roots and further distributed within two plants: Arabidopsis thaliana and Oryza sativa L. by plasma membrane phosphate transporters PHT1 and PHO1 as well as by intracellular transporters: PHO1, PHT2, PHT3, PHT4, PHT5 (VPT1, SPX-MFS and phosphate translocators family. We also describe the role of the PHT1 transporters in mycorrhizal roots of rice as an adaptive strategy to cope with limited phosphate availability in soil.

  7. Auxin and its transport play a role in plant tolerance to arsenite-induced oxidative stress in Arabidopsis thaliana.

    Science.gov (United States)

    Krishnamurthy, Aparna; Rathinasabapathi, Bala

    2013-10-01

    The role of auxin in plant development is well known; however, its possible function in root response to abiotic stress is poorly understood. In this study, we demonstrate a novel role of auxin transport in plant tolerance to oxidative stress caused by arsenite. Plant response to arsenite [As(III)] was evaluated by measuring root growth and markers for stress on seedlings treated with control or As(III)-containing medium. Auxin transporter mutants aux1, pin1 and pin2 were significantly more sensitive to As(III) than the wild type (WT). Auxin transport inhibitors significantly reduced plant tolerance to As(III) in the WT, while exogenous supply of indole-3-acetic acid improved As(III) tolerance of aux1 and not that of WT. Uptake assays using H(3) -IAA showed As(III) affected auxin transport in WT roots. As(III) increased the levels of H2 O2 in WT but not in aux1, suggesting a positive role for auxin transport through AUX1 on plant tolerance to As(III) stress via reactive oxygen species (ROS)-mediated signalling. Compared to the WT, the mutant aux1 was significantly more sensitive to high-temperature stress and salinity, also suggesting auxin transport influences a common element shared by plant tolerance to arsenite, salinity and high-temperature stress.

  8. Epigenetic natural variation in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Matthew W Vaughn

    2007-07-01

    Full Text Available Cytosine methylation of repetitive sequences is widespread in plant genomes, occurring in both symmetric (CpG and CpNpG as well as asymmetric sequence contexts. We used the methylation-dependent restriction enzyme McrBC to profile methylated DNA using tiling microarrays of Arabidopsis Chromosome 4 in two distinct ecotypes, Columbia and Landsberg erecta. We also used comparative genome hybridization to profile copy number polymorphisms. Repeated sequences and transposable elements (TEs, especially long terminal repeat retrotransposons, are densely methylated, but one third of genes also have low but detectable methylation in their transcribed regions. While TEs are almost always methylated, genic methylation is highly polymorphic, with half of all methylated genes being methylated in only one of the two ecotypes. A survey of loci in 96 Arabidopsis accessions revealed a similar degree of methylation polymorphism. Within-gene methylation is heritable, but is lost at a high frequency in segregating F(2 families. Promoter methylation is rare, and gene expression is not generally affected by differences in DNA methylation. Small interfering RNA are preferentially associated with methylated TEs, but not with methylated genes, indicating that most genic methylation is not guided by small interfering RNA. This may account for the instability of gene methylation, if occasional failure of maintenance methylation cannot be restored by other means.

  9. Epigenetic natural variation in Arabidopsis thaliana.

    Science.gov (United States)

    Vaughn, Matthew W; Tanurdzić, Milos; Lippman, Zachary; Jiang, Hongmei; Carrasquillo, Robert; Rabinowicz, Pablo D; Dedhia, Neilay; McCombie, W Richard; Agier, Nicolas; Bulski, Agnès; Colot, Vincent; Doerge, R W; Martienssen, Robert A

    2007-07-01

    Cytosine methylation of repetitive sequences is widespread in plant genomes, occurring in both symmetric (CpG and CpNpG) as well as asymmetric sequence contexts. We used the methylation-dependent restriction enzyme McrBC to profile methylated DNA using tiling microarrays of Arabidopsis Chromosome 4 in two distinct ecotypes, Columbia and Landsberg erecta. We also used comparative genome hybridization to profile copy number polymorphisms. Repeated sequences and transposable elements (TEs), especially long terminal repeat retrotransposons, are densely methylated, but one third of genes also have low but detectable methylation in their transcribed regions. While TEs are almost always methylated, genic methylation is highly polymorphic, with half of all methylated genes being methylated in only one of the two ecotypes. A survey of loci in 96 Arabidopsis accessions revealed a similar degree of methylation polymorphism. Within-gene methylation is heritable, but is lost at a high frequency in segregating F(2) families. Promoter methylation is rare, and gene expression is not generally affected by differences in DNA methylation. Small interfering RNA are preferentially associated with methylated TEs, but not with methylated genes, indicating that most genic methylation is not guided by small interfering RNA. This may account for the instability of gene methylation, if occasional failure of maintenance methylation cannot be restored by other means.

  10. Molecular Genetics of Root Thigmoresponsiveness in Arabidopsis thaliana

    Science.gov (United States)

    Masson, Patrick H.

    2002-01-01

    The molecular mechanisms that allow plant roots to use gravity and touch as growth guides are investigated. We are using a molecular genetic strategy in Arabidopsis thaliana to study these processes. When Arabidopsis thaliana seedlings grow on tilted hard-agar surfaces, their roots develop a wavy pattern of growth which appears to derive from a succession of left-handed and right-handed circumnutation-like processes triggered by gravity and touch stimulation (Okada and Shimura, 1990; Rutherford et al., 1998; Rutherford and Masson, 1996). Interestingly, mutations that affect root waving on tilted hard-agar surfaces can be identified and characterized. Some of these mutations affect root gravitropism, while others appear to be responsible for the production of abnormal waves (no waves, compressed or square waves, coils) without affecting gravitropism. The specific objectives of this project were to functionally characterize two genes (WVD2 and WVD6) which are required for root waving on tilted agar surfaces, but not for root gravitropism. Specific objectives included a physiological and cytological analysis of the mutants, and molecular cloning and characterization of the corresponding genes. As summarized in this paper, we have reached these objectives. We have also identified and partially characterized other mutations that affect root skewing on hard-agar surfaces (sku5-1 and ago1), and have completed our work on the root-wave phenotype associated with mutations in genes of the tryptophan biosynthesis pathway (Lynn et al., 1999; Rutherford et al., 1998; Sedbrook et al., 2000, 2002). We briefly describe our progress on the cloning and characterization of WVD6, WVD2 and SKU5, and provide a list of papers (published, or in preparation) that derived from this grant. We also discuss the biological implications of our findings, with special emphasis on the analysis of WVD2.

  11. Subcellular Distribution of Glutathione Precursors in Arabidopsis thaliana

    Science.gov (United States)

    Koffler, Barbara Eva; Maier, Romana; Zechmann, Bernd

    2011-01-01

    Abstract Glutathione is an important antioxidant and has many important functions in plant development, growth and defense. Glutathione synthesis and degradation is highly compartment-specific and relies on the subcellular availability of its precursors, cysteine, glutamate, glycine and γ-glutamylcysteine especially in plastids and the cytosol which are considered as the main centers for glutathione synthesis. The availability of glutathione precursors within these cell compartments is therefore of great importance for successful plant development and defense. The aim of this study was to investigate the compartment-specific importance of glutathione precursors in Arabidopsis thaliana. The subcellular distribution was compared between wild type plants (Col-0), plants with impaired glutathione synthesis (glutathione deficient pad2-1 mutant, wild type plants treated with buthionine sulfoximine), and one complemented line (OE3) with restored glutathione synthesis. Immunocytohistochemistry revealed that the inhibition of glutathione synthesis induced the accumulation of the glutathione precursors cysteine, glutamate and glycine in most cell compartments including plastids and the cytosol. A strong decrease could be observed in γ-glutamylcysteine (γ-EC) contents in these cell compartments. These experiments demonstrated that the inhibition of γ-glutamylcysteine synthetase (GSH1) – the first enzyme of glutathione synthesis – causes a reduction of γ-EC levels and an accumulation of all other glutathione precursors within the cells. PMID:22050910

  12. CGR2 and CGR3 have critical overlapping roles in pectin methylesterification and plant growth in Arabidopsis thaliana.

    Science.gov (United States)

    Kim, Sang-Jin; Held, Michael A; Zemelis, Starla; Wilkerson, Curtis; Brandizzi, Federica

    2015-04-01

    Pectins are critical polysaccharides of the cell wall that are involved in key aspects of a plant's life, including cell-wall stiffness, cell-to-cell adhesion, and mechanical strength. Pectins undergo methylesterification, which affects their cellular roles. Pectin methyltransferases are believed to methylesterify pectins in the Golgi, but little is known about their identity. To date, there is only circumstantial evidence to support a role for QUASIMODO2 (QUA2)-like proteins and an unrelated plant-specific protein, cotton Golgi-related 3 (CGR3), in pectin methylesterification. To add to the knowledge of pectin biosynthesis, here we characterized a close homolog of CGR3, named CGR2, and evaluated the effect of loss-of-function mutants and over-expression lines of CGR2 and CGR3 in planta. Our results show that, similar to CGR3, CGR2 is a Golgi protein whose enzyme active site is located in the Golgi lumen where pectin methylesterification occurs. Through phenotypical analyses, we also established that simultaneous loss of CGR2 and CGR3 causes severe defects in plant growth and development, supporting critical but overlapping functional roles of these proteins. Qualitative and quantitative cell-wall analytical assays of the double knockout mutant demonstrated reduced levels of pectin methylesterification, coupled with decreased microsomal pectin methyltransferase activity. Conversely, CGR2 and CGR3 over-expression lines have markedly opposite phenotypes to the double knockout mutant, with increased cell-wall methylesterification levels and microsomal pectin methyltransferase activity. Based on these findings, we propose that CGR2 and CGR3 are critical proteins in plant growth and development that act redundantly in pectin methylesterification in the Golgi apparatus.

  13. A novel system for xylem cell differentiation in Arabidopsis thaliana.

    Science.gov (United States)

    Kondo, Yuki; Fujita, Takashi; Sugiyama, Munetaka; Fukuda, Hiroo

    2015-04-01

    During vascular development, procambial and cambial cells give rise to xylem and phloem cells. Because the vascular tissue is deeply embedded, it has been difficult to analyze the processes of vascular development in detail. Here, we establish a novel in vitro experimental system in which vascular development is induced in Arabidopsis thaliana leaf-disk cultures using bikinin, an inhibitor of glycogen synthase kinase 3 proteins. Transcriptome analysis reveals that mesophyll cells in leaf disks synchronously turn into procambial cells and then differentiate into tracheary elements. Leaf-disk cultures from plants expressing the procambial cell markers TDR(pro):GUS and TDR(pro):YFP can be used for spatiotemporal visualization of procambial cell formation. Further analysis with the tdr mutant and TDIF (tracheary element differentiation inhibitory factor) indicates that the key signaling TDIF-TDR-GSK3s regulates xylem differentiation in leaf-disk cultures. This new culture system can be combined with analysis using the rich material resources for Arabidopsis including cell-marker lines and mutants, thus offering a powerful tool for analyzing xylem cell differentiation. Copyright © 2015 The Author. Published by Elsevier Inc. All rights reserved.

  14. Insertions/deletions-associated nucleotide polymorphism in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Changjiang Guo

    2016-11-01

    Full Text Available Although high levels of within-species variation are commonly observed, a general mechanism for the origin of such variation is still lacking. Insertions and deletions (indels are a widespread feature of genomes and we hypothesize that there might be an association between indels and patterns of nucleotide polymorphism. Here, we investigate flanking sequences around 18 indels (>100bp among a large number of accessions of the plant, Arabidopsis thaliana. We found two distinct haplotypes, i.e. a nucleotide dimorphism, present around each of these indels and dimorphic haplotypes always corresponded to the indel-present/-absent patterns. In addition, the peaks of nucleotide diversity between the two divergent alleles were closely associated with these indels. Thus, there exists a close association between indels and dimorphisms. Further analysis suggests that indel-associated substitutions could be an important component of genetic variation shaping nucleotide polymorphism in Arabidopsis. Finally, we suggest a mechanism by which indels might generate these highly divergent haplotypes. This study provides evidence that nucleotide dimorphisms, which are frequently regarded as evidence of frequency-dependent selection, could be explained simply by structural variation in the genome.

  15. The RNA-binding protein repertoire of Arabidopsis thaliana

    KAUST Repository

    Marondedze, Claudius

    2016-07-11

    RNA-binding proteins (RBPs) have essential roles in determining the fate of RNA from synthesis to decay and have been studied on a protein-by-protein basis, or computationally based on a number of well-characterised RNA-binding domains. Recently, high-throughput methods enabled the capture of mammalian RNA-binding proteomes. To gain insight into the role of Arabidopsis thaliana RBPs at the systems level, we have employed interactome capture techniques using cells from different ecotypes grown in cultures and leaves. In vivo UV-crosslinking of RNA to RBPs, oligo(dT) capture and mass spectrometry yielded 1,145 different proteins including 550 RBPs that either belong to the functional category ‘RNA-binding’, have known RNA-binding domains or have orthologs identified in mammals, C. elegans, or S. cerevisiae in addition to 595 novel candidate RBPs. We noted specific subsets of RBPs in cultured cells and leaves and a comparison of Arabidopsis, mammalian, C. elegans, and S. cerevisiae RBPs reveals a common set of proteins with a role in intermediate metabolism, as well as distinct differences suggesting that RBPs are also species and tissue specific. This study provides a foundation for studies that will advance our understanding of the biological significance of RBPs in plant developmental and stimulus specific responses.

  16. Protein Degradation Rate in Arabidopsis thaliana Leaf Growth and Development.

    Science.gov (United States)

    Li, Lei; Nelson, Clark J; Trösch, Josua; Castleden, Ian; Huang, Shaobai; Millar, A Harvey

    2017-02-01

    We applied (15)N labeling approaches to leaves of the Arabidopsis thaliana rosette to characterize their protein degradation rate and understand its determinants. The progressive labeling of new peptides with (15)N and measuring the decrease in the abundance of >60,000 existing peptides over time allowed us to define the degradation rate of 1228 proteins in vivo. We show that Arabidopsis protein half-lives vary from several hours to several months based on the exponential constant of the decay rate for each protein. This rate was calculated from the relative isotope abundance of each peptide and the fold change in protein abundance during growth. Protein complex membership and specific protein domains were found to be strong predictors of degradation rate, while N-end amino acid, hydrophobicity, or aggregation propensity of proteins were not. We discovered rapidly degrading subunits in a variety of protein complexes in plastids and identified the set of plant proteins whose degradation rate changed in different leaves of the rosette and correlated with leaf growth rate. From this information, we have calculated the protein turnover energy costs in different leaves and their key determinants within the proteome.

  17. [Regulation pattern of the FRUITFULL (FUL) gene of Arabidopsis thaliana].

    Science.gov (United States)

    Chu, Tingting; Xie, Hua; Xu, Yong; Ma, Rongcai

    2010-11-01

    FRUITFULL (FUL) is an MADS box gene that functions early in controlling flowering time, meristem identity and cauline leaf morphology and later in carpel and fruit development in Arabidopsis thaliana. In order to clarify the regulation of FUL expression the upstream regulatory region, -2148 bp - +96 bp and the first intron of the FUL gene were cloned, and vectors with a series of deletion of FUL promoter, and the ones fused with the first intron were constructed. Vectors harboring the fusion of cis-acting elements with the constitutive promoters of TUBULIN and ACTIN were also constructed. Beta-Glucuronidase activity assays of the transgenic Arabidopsis plants showed that two cis-elements were involved in the repression of FUL expression, with one of the two being probably the binding site of the transcriptional factor AP1. And the two CArG boxes played a important role in FUL initiation particularly. Furthermore, the first intron of FUL was shown to participate in the development of carpel and stamen as an enhancer.

  18. Riboflavin-induced Priming for Pathogen Defense in Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    Shujian Zhang; Xue Yang; Maowu Sun; Feng Sun; Sheng Deng; Hansong Dong

    2009-01-01

    Riboflavin (vitamin B2) participates in a variety of redox processes that affect plant defense responses. Previously we have shown that riboflavin induces pathogen resistance in the absence of hypersensitive cell death (HCD) in plants. Herein, we report that riboflavin induces priming of defense responses in Arabidopsis thaliana toward infection by virulent Pseudomonas syringae pv. Tomato DC3000 (Pst). Induced resistance was mechanistically connected with the expression of defense response genes and cellular defense events, including H2O2 burst, HCD, and callose deposition in the plant. Riboflavin treatment and inoculation of plants with Pst were neither active but both synergized to induce defense responses. The priming process needed NPR1 (essential regulator of systemic acquired resistance) and maintenance of H2O2 burst but was independent of salicylic acid, jasmonic acid, ethylene, and abscisic acid. Our results suggest that the role of riboflavin in priming defenses is subject to a signaling process distinct from the known pathways of hormone signal transduction.

  19. Phytotoxicity, accumulation and transport of silver nanoparticles by Arabidopsis thaliana.

    Science.gov (United States)

    Geisler-Lee, Jane; Wang, Qiang; Yao, Ying; Zhang, Wen; Geisler, Matt; Li, Kungang; Huang, Ying; Chen, Yongsheng; Kolmakov, Andrei; Ma, Xingmao

    2013-05-01

    The widespread availability of nano-enabled products in the global market may lead to the release of a substantial amount of engineered nanoparticles in the environment, which frequently display drastically different physiochemical properties than their bulk counterparts. The purpose of the study was to evaluate the impact of citrate-stabilised silver nanoparticles (AgNPs) on the plant Arabidopsis thaliana at three levels, physiological phytotoxicity, cellular accumulation and subcellular transport of AgNPs. The monodisperse AgNPs of three different sizes (20, 40 and 80 nm) aggregated into much larger sizes after mixing with quarter-strength Hoagland solution and became polydisperse. Immersion in AgNP suspension inhibited seedling root elongation and demonstrated a linear dose-response relationship within the tested concentration range. The phytotoxic effect of AgNPs could not be fully explained by the released silver ions. Plants exposed to AgNP suspensions bioaccumulated higher silver content than plants exposed to AgNO3 solutions (Ag(+) representative), indicating AgNP uptake by plants. AgNP toxicity was size and concentration dependent. AgNPs accumulated progressively in this sequence: border cells, root cap, columella and columella initials. AgNPs were apoplastically transported in the cell wall and found aggregated at plasmodesmata. In all the three levels studied, AgNP impacts differed from equivalent dosages of AgNO3.

  20. Differential tissue accumulation of 2,3,7,8-Tetrachlorinated dibenzo-p-dioxin in Arabidopsis thaliana affects plant chronology, lipid metabolism and seed yield.

    Science.gov (United States)

    Hanano, Abdulsamie; Almousally, Ibrahem; Shaban, Mouhnad; Moursel, Nour; Shahadeh, AbdAlbaset; Alhajji, Eskander

    2015-08-11

    Dioxins are one of the most toxic groups of persistent organic pollutants. Their biotransmission through the food chain constitutes a potential risk for human health. Plants as principal actors in the food chain can play a determinant role in removing dioxins from the environment. Due to the lack of data on dioxin/plant research, this study sets out to determine few responsive reactions adopted by Arabidopsis plant towards 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), the most toxic congener of dioxins. Using a high resolution gas chromatography/mass spectrometry, we demonstrated that Arabidopsis plant uptakes TCDD by the roots and accumulates it in the vegetative parts in a tissue-specific manner. TCDD mainly accumulated in rosette leaves and mature seeds and less in stem, flowers and immature siliques. Moreover, we observed that plants exposed to high doses of TCDD exhibited a delay in flowering and yielded fewer seeds of a reduced oil content with a low vitality. A particular focus on the plant fatty acid metabolism showed that TCDD caused a significant reduction in C18-unsaturated fatty acid level in plant tissues. Simultaneously, TCDD induced the expression of 9-LOX and 13-LOX genes and the formation of their corresponding hydroperoxides, 9- and 13-HPOD as well as 9- or 13-HPOT, derived from linoleic and linolenic acids, respectively. The current work highlights a side of toxicological effects resulting in the administration of 2,3,7,8-TCDD on the Arabidopsis plant. Similarly to animals, it seems that plants may accumulate TCDD in their lipids by involving few of the FA-metabolizing enzymes for sculpting a specific oxylipins "signature" typified to plant TCDD-tolerance. Together, our results uncover novel responses of Arabidopsis to dioxin, possibly emerging to overcome its toxicity.

  1. Ectopic expression of a phytochrome B gene from Chinese cabbage (Brassica rapa L. ssp. pekinensis) in Arabidopsis thaliana promotes seedling de-etiolation, dwarfing in mature plants, and delayed flowering.

    Science.gov (United States)

    Song, Mei-Fang; Zhang, Shu; Hou, Pei; Shang, Hong-Zhong; Gu, Hai-Ke; Li, Jing-Juan; Xiao, Yang; Guo, Lin; Su, Liang; Gao, Jian-Wei; Yang, Jian-Ping

    2015-04-01

    Phytochrome B (phyB) is an essential red light receptor that predominantly mediates seedling de-etiolation, shade-avoidance response, and flowering time. In this study, we isolate a full-length cDNA of PHYB, designated BrPHYB, from Chinese cabbage (Brassica rapa L. ssp. pekinensis), and we find that BrphyB protein has high amino acid sequence similarity and the closest evolutionary relationship to Arabidopsis thaliana phyB (i.e., AtphyB). Quantitative reverse transcription (RT)-PCR results indicate that the BrPHYB gene is ubiquitously expressed in different tissues under all light conditions. Constitutive expression of the BrPHYB gene in A. thaliana significantly enhances seedling de-etiolation under red- and white-light conditions, and causes dwarf stature in mature plants. Unexpectedly, overexpression of BrPHYB in transgenic A. thaliana resulted in reduced expression of gibberellins biosynthesis genes and delayed flowering under short-day conditions, whereas AtPHYB overexpression caused enhanced expression of FLOWERING LOCUS T and earlier flowering. Our results suggest that BrphyB might play an important role in regulating the development of Chinese cabbage. BrphyB and AtphyB have conserved functions during de-etiolation and vegetative plant growth and divergent functions in the regulation of flowering time.

  2. Putrescine accumulation in Arabidopsis thaliana transgenic lines enhances tolerance to dehydration and freezing stress

    OpenAIRE

    Alet, Analía I; Sanchez, Diego H; Cuevas, Juan C.; del Valle, Secundino; Altabella, Teresa; Tiburcio, Antonio F.; Marco, Francisco; Ferrando, Alejandro; Espasandín, Fabiana D; María E. González; Carrasco, Pedro; Ruiz, Oscar A.

    2011-01-01

    Polyamines have been globally associated to plant responses to abiotic stress. Particularly, putrescine has been related to a better response to cold and dehydration stresses. It is known that this polyamine is involved in cold tolerance, since Arabidopsis thaliana plants mutated in the key enzyme responsible for putrescine synthesis (arginine decarboxilase, ADC; EC 4.1.1.19) are more sensitive than the wild type to this stress. Although it is speculated that the overexpression of ADC genes m...

  3. Transgenerational stress memory in Arabidopsis thaliana (L.) Heynh.: antioxidative enzymes and HSP70

    OpenAIRE

    Ćuk, Katarina; Gogalo, Marko; Tkalec, Mirta; Vidaković-Cifrek, Željka

    2010-01-01

    Transgenerational transmission of information about stress exposure is manifested as an increase in the somatic homologous recombination frequency in plants. Our aim was to investigate whether information about changes of antioxidative enzyme activities and protein HSP70 induction are also transmitted in response to stress caused by UV-C irradiation. These stress indicators were investigated in Arabidopsis thaliana plants exposed to UV-C irradiation (6 and 600 J m-2) and its non-irradiated pr...

  4. Adaptation response of Arabidopsis thaliana to random positioning

    NARCIS (Netherlands)

    Kittang, A.I.; Winge, P.; van Loon, J.J.W.A.; Bones, A.M.; Iversen, T.H.

    2013-01-01

    Arabidopsis thaliana seedlings were exposed on a Random Positioning Machine (RPM) under light conditions for 16 h and the samples were analysed using microarray techniques as part of a preparation for a space experiment on the International Space Station (ISS). The results demonstrated a moderate to

  5. An extensive microarray analysis of AAL-toxin-induced cell death in Arabidopsis thaliana brings new insights into the complexity of programmed cell death in plants

    NARCIS (Netherlands)

    Gechev, T.S.; Gadjev, I.Z.; Hille, J.

    2004-01-01

    A T-DNA knockout of the Arabidopsis homologue of the tomato disease resistance gene Asc was obtained. The asc gene renders plants sensitive to programmed cell death (PCD) triggered by the fungal AAL toxin. To obtain more insights into the nature of AAL-toxin-induced cell death and to identify genes

  6. Partial functional conservation of IRX10 homologs in physcomitrella patens and Arabidopsis thaliana indicates an evolutionary step contributing to vascular formation in land plants

    Directory of Open Access Journals (Sweden)

    Hörnblad Emma

    2013-01-01

    Full Text Available Abstract Background Plant cell walls are complex multicomponent structures that have evolved to fulfil an essential function in providing strength and protection to cells. Hemicelluloses constitute a key component of the cell wall and recently a number of the genes thought to encode the enzymes required for its synthesis have been identified in Arabidopsis. The acquisition of hemicellulose synthesis capability is hypothesised to have been an important step in the evolution of higher plants. Results Analysis of the Physcomitrella patens genome has revealed the presence of homologs for all of the Arabidopsis glycosyltransferases including IRX9, IRX10 and IRX14 required for the synthesis of the glucuronoxylan backbone. The Physcomitrella IRX10 homolog is expressed in a variety of moss tissues which were newly formed or undergoing expansion. There is a high degree of sequence conservation between the Physcomitrella IRX10 and Arabidopsis IRX10 and IRX10-L. Despite this sequence similarity, the Physcomitrella IRX10 gene is only able to partially rescue the Arabidopsis irx10 irx10-L double mutant indicating that there has been a neo- or sub-functionalisation during the evolution of higher plants. Analysis of the monosaccharide composition of stems from the partially rescued Arabidopsis plants does not show any significant change in xylose content compared to the irx10 irx10-L double mutant. Likewise, knockout mutants of the Physcomitrella IRX10 gene do not result in any visible phenotype and there is no significant change in monosaccharide composition of the cell walls. Conclusions The fact that the Physcomitrella IRX10 (PpGT47A protein can partially complement an Arabidopsis irx10 irx10-L double mutant suggests that it shares some function with the Arabidopsis proteins, but the lack of a phenotype in knockout lines shows that the function is not required for growth or development under normal conditions in Physcomitrella. In contrast, the Arabidopsis

  7. Molecular cell biology of male meiotic chromosomes and isolation of male meiocytes in Arabidopsis thaliana.

    Science.gov (United States)

    Wang, Yingxiang; Cheng, Zhihao; Lu, Pingli; Timofejeva, Ljudmilla; Ma, Hong

    2014-01-01

    Plants typically produce numerous flowers whose meiotic chromosomes are relatively easy to observe, making them excellent structures for studying the cellular processes underlying meiosis. In recent years, breakthroughs in light and electron microscopic technologies for small chromosomes, combined with molecular genetic methods, have resulted in major advances in the understanding of meiosis in the model plant Arabidopsis thaliana. In this chapter, we summarize protocols for basic cytology, fluorescence in situ hybridization, immunofluorescence, electron microscopy, and isolation of male meiocytes for the analysis of Arabidopsis meiosis.

  8. Novel features of radiation-induced bystander signaling in Arabidopsis thaliana demonstrated using root micro-grafting

    OpenAIRE

    Wang, Ting; Li, Fanghua; Xu, Wei; Bian, Po; Wu, Yuejin; WU, LIJUN

    2012-01-01

    Radiation-induced bystander effects (RIBE) have been well demonstrated in whole organisms, as well as in single-cell culture models in vitro and multi-cellular tissues models in vitro, however, the underlying mechanisms remain unclear, including the temporal and spatial course of bystander signaling. The RIBE in vivo has been shown to exist in the model plant Arabidopsis thaliana (A. thaliana). Importantly, the unique plant grafting provides a delicate approach for studying the temporal and s...

  9. Seed-to-seed growth of Arabidopsis thaliana on the International Space Station

    Science.gov (United States)

    Link, B. M.; Durst, S. J.; Zhou, W.; Stankovic, B.

    2003-01-01

    The assembly of the International Space Station (ISS) as a permanent experimental outpost has provided the opportunity for quality plant research in space. To take advantage of this orbital laboratory, engineers and scientists at the Wisconsin Center for Space Automation and Robotics (WCSAR), University of Wisconsin-Madison, developed a plant growth facility capable of supporting plant growth in the microgravity environment. Utilizing this Advanced Astroculture (ADVASC) plant growth facility, an experiment was conducted with the objective to grow Arabidopsis thaliana plants from seed-to-seed on the ISS. Dry Arabidopsis seeds were anchored in the root tray of the ADVASC growth chamber. These seeds were successfully germinated from May 10 until the end of June 2001. Arabidopsis plants grew and completed a full life cycle in microgravity. This experiment demonstrated that ADVASC is capable of providing environment conditions suitable for plant growth and development in microgravity. The normal progression through the life cycle, as well as the postflight morphometric analyses, demonstrate that Arabidopsis thaliana does not require the presence of gravity for growth and development. c2003 COSPAR. Published by Elsevier Ltd. All rights reserved.

  10. The Arabidopsis thaliana Nuclear Factor Y Transcription Factors

    Science.gov (United States)

    Zhao, Hang; Wu, Di; Kong, Fanying; Lin, Ke; Zhang, Haishen; Li, Gang

    2017-01-01

    Nuclear factor Y (NF-Y) is an evolutionarily conserved trimeric transcription factor complex present in nearly all eukaryotes. The heterotrimeric NF-Y complex consists of three subunits, NF-YA, NF-YB, and NF-YC, and binds to the CCAAT box in the promoter regions of its target genes to regulate their expression. Yeast and mammal genomes generally have single genes with multiple splicing isoforms that encode each NF-Y subunit. By contrast, plant genomes generally have multi-gene families encoding each subunit and these genes are differentially expressed in various tissues or stages. Therefore, different subunit combinations can lead to a wide variety of NF-Y complexes in various tissues, stages, and growth conditions, indicating the potentially diverse functions of this complex in plants. Indeed, many recent studies have proved that the NF-Y complex plays multiple essential roles in plant growth, development, and stress responses. In this review, we highlight recent progress on NF-Y in Arabidopsis thaliana, including NF-Y protein structure, heterotrimeric complex formation, and the molecular mechanism by which NF-Y regulates downstream target gene expression. We then focus on its biological functions and underlying molecular mechanisms. Finally, possible directions for future research on NF-Y are also presented.

  11. Measurement of 2-carboxyarabinitol 1-phosphate in plant leaves by isotope dilution. [Spinacea oleracea; Triticum aestivum; Arabidopsis thaliana; Maize; Phaseolus vulgaris; Petunia hybrida

    Energy Technology Data Exchange (ETDEWEB)

    Moore, B.D.; Kobza, J.; Seemann, J.R. (Univ. of Nevada, Reno (United States))

    1991-05-01

    The level of 2-carboxyarabinitol 1-phosphate (CA1P) in leaves of 12 species was determined by an isotope dilution assay. {sup 14}C-labeled standard was synthesized from (2-{sup 14}C)carboxyarabinitol 1,5-bisphosphate using acid phosphatase, and was added at the initial point of leaf extraction. Leaf CA1P was purified and its specific activity determined. CA1P was found in dark-treated leaves of all species examined, including spinach (Spinacea oleracea), wheat (Triticum aestivum), Arabidopsis thaliana, and maize (Zea mays). The highest amounts were found in bean (Phaseolus vulgaris) and petunia (Petunia hybrida), which had 1.5 to 1.8 moles CA1P per mole ribulose 1,5-bisphosphate carboxylase catalytic sites. Most species had intermediate amounts of CA1P (0.2 to 0.8 mole CA1P per mole catalytic sites). Such intermediate to high levels of CA1P support the hypothesis that CA1P functions in many species as a light-dependent regulator of ribulose 1,5-bisphosphate carboxylase activity and whole leaf photosynthetic CO{sub 2} assimilation. However, CA1P levels in spinach, wheat, and A. thaliana were particularly low (less than 0.09 mole CA1P per mole catalytic sites). In such species, CA1P does not likely have a significant role in regulating ribulose 1,5-bisphosphate carboxylase activity, but could have a different physiological role.

  12. Expression differences for genes involved in lignin, glutathione and sulphate metabolism in response to cadmium in Arabidopsis thaliana and the related Zn/Cd-hyperaccumulator Thlaspi caerulescens

    NARCIS (Netherlands)

    Mortel, van de J.E.; Schat, H.; Moerland, P.D.; Loren van Themaat, Ver E.; Ent, van der S.; Blankestijn-de Vries, M.H.C.; Ghandilyan, A.; Tsiatsiani, S.; Aarts, M.G.M.

    2008-01-01

    Cadmium (Cd) is a widespread, naturally occurring element present in soil, rock, water, plants and animals. Cd is a non-essential element for plants and is toxic at higher concentrations. Transcript profiles of roots of Arabidopsis thaliana (Arabidopsis) and Thlaspi caerulescens plants exposed to Cd

  13. Establishment of an Indirect Genetic Transformation Method for Arabidopsis thaliana ecotype Bangladesh

    Directory of Open Access Journals (Sweden)

    Bulbul AHMED

    2011-11-01

    Full Text Available Arabidopsis thaliana is a small flowering plant belonging to the Brassicaceae family, which is adopted as a model plant for genetic research. Agrobacterium tumifaciensmediated transformation method for A. thaliana ecotype Bangladesh was established. Leaf discs of A. thaliana were incubated with A. tumefaciens strain LBA4404 containing chimeric nos. nptII. nos and intron-GUS genes. Following inoculation and co-cultivation, leaf discs were cultured on selection medium containing 50 mg/l kanamycin + 50 mg/l cefotaxime + 1.5 mg/l NAA and kanamycin resistant shoots were induced from the leaf discs after two weeks. Shoot regeneration was achieved after transferring the tissues onto fresh medium of the same combination. Finally, the shoots were rooted on MS medium containing 50 mg/l kanamycin. Incorporation and expression of the transgenes were confirmed by PCR analysis. Using this protocol, transgenic A. thaliana plants can be obtained and indicates that genomic transformation in higher plants is possible through insertion of desired gene. Although Agrobacterium mediated genetic transformation is established for A. thaliana, this study was the conducted to transform A. thaliana ecotype Bangladesh.

  14. The evolution of transposable elements in natural populations of self-fertilizing Arabidopsis thaliana and its outcrossing relative Arabidopsis lyrata

    Directory of Open Access Journals (Sweden)

    Gaut Brandon S

    2010-01-01

    Full Text Available Abstract Background Transposable Elements (TEs make up the majority of plant genomes, and thus understanding TE evolutionary dynamics is key to understanding plant genome evolution. Plant reproductive systems are diverse and mating type variation is one factor among many hypothesized to influence TE evolutionary dynamics. Here, we collected a large TE-display data set in self-fertilizing Arabidopsis thaliana, and compared it to data gathered in outcrossing Arabidopsis lyrata. We analyzed seven TE families in four natural populations of each species to tease apart the effects of mating system, demography, transposition, and selection in determining patterns of TE diversity. Results Measures of TE band differentiation were largely consistent across TE families. However, patterns of diversity in A. thaliana Ac elements differed significantly from that other TEs, perhaps signaling a lack of recent transposition. Across TE families, we estimated higher allele frequencies and lower selection coefficients on A. thaliana TE insertions relative to A. lyrata TE insertions. Conclusions The differences in TE distributions between the two Arabidopsis species represents a synthesis of evolutionary forces that include the transposition dynamics of individual TE families and the demographic histories of populations. There are also species-specific differences that could be attributed to the effects of mating system, including higher overall allele frequencies in the selfing lineage and a greater proportion of among population TE diversity in the outcrossing lineage.

  15. Arabidopsis thaliana mTERF proteins: evolution and functional classification

    Directory of Open Access Journals (Sweden)

    Tatjana eKleine

    2012-10-01

    Full Text Available Organellar gene expression (OGE is crucial for plant development, photosynthesis and respiration, but our understanding of the mechanisms that control it is still relatively poor. Thus, OGE requires various nucleus-encoded proteins that promote transcription, splicing, trimming and editing of organellar RNAs, and regulate translation. In metazoans, proteins of the mitochondrial Transcription tERmination Factor (mTERF family interact with the mitochondrial chromosome and regulate transcriptional initiation and termination. Sequencing of the Arabidopsis thaliana genome led to the identification of a diversified MTERF gene family but, in contrast to mammalian mTERFs, knowledge about the function of these proteins in photosynthetic organisms is scarce. In this hypothesis article, I show that tandem duplications and one block duplication contributed to the large number of MTERF genes in A. thaliana, and propose that the expansion of the family is related to the evolution of land plants. The MTERF genes - especially the duplicated genes - display a number of distinct mRNA accumulation patterns, suggesting functional diversification of mTERF proteins to increase adaptability to environmental changes. Indeed, hypothetical functions for the different mTERF proteins can be predicted using co-expression analysis and gene ontology annotations. On this basis, mTERF proteins can be sorted into five groups. Members of the chloroplast and chloroplast-associated clusters are principally involved in chloroplast gene expression, embryogenesis and protein catabolism, while representatives of the mitochondrial cluster seem to participate in DNA and RNA metabolism in that organelle. Moreover, members of the mitochondrion-associated cluster and the low expression group may act in the nucleus and/or the cytosol. As proteins involved in OGE and presumably nuclear gene expression, mTERFs are ideal candidates for the coordination of the expression of organelle and nuclear

  16. Activity of the AtMRP3 promoter in transgenic Arabidopsis thaliana and Nicotiana tabacum plants is increased by cadmium, nickel, arsenic, cobalt and lead but not by zinc and iron.

    Science.gov (United States)

    Zientara, Katarzyna; Wawrzyńska, Anna; Lukomska, Jolanta; López-Moya, José Rafael; Liszewska, Frantz; Assunção, Ana G L; Aarts, Mark G M; Sirko, Agnieszka

    2009-02-05

    Characterization of the function, regulation and metal-specificity of metal transporters is one of the basic steps needed for the understanding of transport and accumulation of toxic metals and metalloids by plants. In this work GUS was used as a reporter for monitoring the activity of the promoter of the AtMRP3 gene from Arabidopsis thaliana, a gene encoding an ABC-transporter, expression of which is induced by heavy metals. The AtMRP3 promoter-GUS fusion expression cassette was introduced into the genome of two model plants, A. thaliana and Nicotiana tabacum. The promoter induces GUS activity in the roots as well as in the shoots upon metal exposure. Similar responses of the AtMRP3 promoter to the presence of the selected metals was observed in both plant species. Cadmium, nickel, arsenic, cobalt and lead strongly activated the transcription of the reporter gene, while zinc and iron had no impact. The AtMRP3 promoter thus seems to be a useful new tool in designing plants that can be used for biomonitoring of environmental contaminations.

  17. Quantitative divergence of the bacterial root microbiota in Arabidopsis thaliana relatives.

    Science.gov (United States)

    Schlaeppi, Klaus; Dombrowski, Nina; Oter, Ruben Garrido; Ver Loren van Themaat, Emiel; Schulze-Lefert, Paul

    2014-01-14

    Plants host at the contact zone with soil a distinctive root-associated bacterial microbiota believed to function in plant nutrition and health. We investigated the diversity of the root microbiota within a phylogenetic framework of hosts: three Arabidopsis thaliana ecotypes along with its sister species Arabidopsis halleri and Arabidopsis lyrata, as well as Cardamine hirsuta, which diverged from the former ∼ 35 Mya. We surveyed their microbiota under controlled environmental conditions and of A. thaliana and C. hirsuta in two natural habitats. Deep 16S rRNA gene profiling of root and corresponding soil samples identified a total of 237 quantifiable bacterial ribotypes, of which an average of 73 community members were enriched in roots. The composition of this root microbiota depends more on interactions with the environment than with host species. Interhost species microbiota diversity is largely quantitative and is greater between the three Arabidopsis species than the three A. thaliana ecotypes. Host species-specific microbiota were identified at the levels of individual community members, taxonomic groups, and whole root communities. Most of these signatures were observed in the phylogenetically distant C. hirsuta. However, the branching order of host phylogeny is incongruent with interspecies root microbiota diversity, indicating that host phylogenetic distance alone cannot explain root microbiota diversification. Our work reveals within 35 My of host divergence a largely conserved and taxonomically narrow root microbiota, which comprises stable community members belonging to the Actinomycetales, Burkholderiales, and Flavobacteriales.

  18. A sequence based synteny map between soybean and Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Lightfoot David A

    2007-01-01

    Full Text Available Abstract Background Soybean (Glycine max, L. Merr. is one of the world's most important crops, however, its complete genomic sequence has yet to be determined. Nonetheless, a large body of sequence information exists, particularly in the form of expressed sequence tags (ESTs. Herein, we report the use of the model organism Arabidopsis thaliana (thale cress for which the entire genomic sequence is available as a framework to align thousands of short soybean sequences. Results A series of JAVA-based programs were created that processed and compared 341,619 soybean DNA sequences against A. thaliana chromosomal DNA. A. thaliana DNA was probed for short, exact matches (15 bp to each soybean sequence, and then checked for the number of additional 7 bp matches in the adjacent 400 bp region. The position of these matches was used to order soybean sequences in relation to the A. thaliana genome. Conclusion Reported associations between soybean sequences and A. thaliana were within a 95% confidence interval of e-30 – e-100. In addition, the clustering of soybean expressed sequence tags (ESTs based on A. thaliana sequence was accurate enough to identify potential single nucleotide polymorphisms (SNPs within the soybean sequence clusters. An EST, bacterial artificial chromosome (BAC end sequence and marker amplicon sequence synteny map of soybean and A. thaliana is presented. In addition, all JAVA programs used to create this map are available upon request and on the WEB.

  19. Small RNA-directed epigenetic natural variation in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Jixian Zhai

    2008-04-01

    Full Text Available Progress in epigenetics has revealed mechanisms that can heritably regulate gene function independent of genetic alterations. Nevertheless, little is known about the role of epigenetics in evolution. This is due in part to scant data on epigenetic variation among natural populations. In plants, small interfering RNA (siRNA is involved in both the initiation and maintenance of gene silencing by directing DNA methylation and/or histone methylation. Here, we report that, in the model plant Arabidopsis thaliana, a cluster of approximately 24 nt siRNAs found at high levels in the ecotype Landsberg erecta (Ler could direct DNA methylation and heterochromatinization at a hAT element adjacent to the promoter of FLOWERING LOCUS C (FLC, a major repressor of flowering, whereas the same hAT element in ecotype Columbia (Col with almost identical DNA sequence, generates a set of low abundance siRNAs that do not direct these activities. We have called this hAT element MPF for Methylated region near Promoter of FLC, although de novo methylation triggered by an inverted repeat transgene at this region in Col does not alter its FLC expression. DNA methylation of the Ler allele MPF is dependent on genes in known silencing pathways, and such methylation is transmissible to Col by genetic crosses, although with varying degrees of penetrance. A genome-wide comparison of Ler and Col small RNAs identified at least 68 loci matched by a significant level of approximately 24 nt siRNAs present specifically in Ler but not Col, where nearly half of the loci are related to repeat or TE sequences. Methylation analysis revealed that 88% of the examined loci (37 out of 42 were specifically methylated in Ler but not Col, suggesting that small RNA can direct epigenetic differences between two closely related Arabidopsis ecotypes.

  20. Myosin inhibitors block accumulation movement of chloroplasts in Arabidopsis thaliana leaf cells.

    Science.gov (United States)

    Paves, H; Truve, E

    2007-01-01

    Chloroplasts alter their distribution within plant cells depending on the external light conditions. Myosin inhibitors 2,3-butanedione monoxime (BDM), N-ethylmaleimide (NEM), and 1-(5-iodonaphthalene-1-sulfonyl)-1H-hexahydro-1,4-diazepine hydrochloride (ML-7) were used to study the possible role of myosins in chloroplast photorelocation in Arabidopsis thaliana mesophyll cells. None of these agents had an effect on the chloroplast high-fluence-rate avoidance movement but all of the three myosin inhibitors blocked the accumulation movement of chloroplasts after a high-fluence-rate irradiation of the leaves. The results suggest that myosins have a role in A. thaliana chloroplast photorelocation.

  1. Azospirillum brasilense ameliorates the response of Arabidopsis thaliana to drought mainly via enhancement of ABA levels.

    Science.gov (United States)

    Cohen, Ana C; Bottini, Rubén; Pontin, Mariela; Berli, Federico J; Moreno, Daniela; Boccanlandro, Hernán; Travaglia, Claudia N; Piccoli, Patricia N

    2015-01-01

    Production of phytohormones is one of the main mechanisms to explain the beneficial effects of plant growth-promoting rhizobacteria (PGPR) such as Azospirillum sp. The PGPRs induce plant growth and development, and reduce stress susceptibility. However, little is known regarding the stress-related phytohormone abscisic acid (ABA) produced by bacteria. We investigated the effects of Azospirillum brasilense Sp 245 strain on Arabidopsis thaliana Col-0 and aba2-1 mutant plants, evaluating the morphophysiological and biochemical responses when watered and in drought. We used an in vitro-grown system to study changes in the root volume and architecture after inoculation with Azospirillum in Arabidopsis wild-type Col-0 and on the mutant aba2-1, during early growth. To examine Arabidopsis development and reproductive success as affected by the bacteria, ABA and drought, a pot experiment using Arabidopsis Col-0 plants was also carried out. Azospirillum brasilense augmented plant biomass, altered root architecture by increasing lateral roots number, stimulated photosynthetic and photoprotective pigments and retarded water loss in correlation with incremented ABA levels. As well, inoculation improved plants seed yield, plants survival, proline levels and relative leaf water content; it also decreased stomatal conductance, malondialdehyde and relative soil water content in plants submitted to drought. Arabidopsis inoculation with A. brasilense improved plants performance, especially in drought.

  2. A proteomics study of auxin effects in Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    Meiqing Xing; Hongwei Xue

    2012-01-01

    Many phytohormones regulate plant growth and development through modulating protein degradation.In this study,a proteome study based on multidimensional non-gel shotgun approach was performed to analyze the auxin-induced protein degradation via ubiquitinproteasome pathway of Arabidopsis thaliana,with the emphasis to study the overall protein changes after auxin treatment (1 nM or 1 μM indole-3-acetic acid for 6,12,or 24 h).More than a thousand proteins were detected by using label-free shotgun method,and 386 increased proteins and 370 decreased ones were identified after indole-3-acetic acid treatment.By using the auxin receptor-deficient mutant,tir1-1,as control,comparative analysis revealed that 69 and 79 proteins were significantly decreased and increased,respectively.Detailed analysis showed that among the altered proteins,some were previously reported to be associated with auxin regulation and others are potentially involved in mediating the auxin effects on specific cellular and physiological processes by regulating photosynthesis,chloroplast development,cytoskeleton,and intracellular signaling.Our results demonstrated that label-free shotgun proteomics is a powerful tool for large-scale protein identification and the analysis of the proteomic profiling of auxin-regulated biological processes will provide informative clues of underlying mechanisms of auxin effects.These results will help to expand the understanding of how auxin regulates plant growth and development via protein degradation.

  3. Lagging adaptation to warming climate in Arabidopsis thaliana

    Science.gov (United States)

    Wilczek, Amity M.; Cooper, Martha D.; Korves, Tonia M.; Schmitt, Johanna

    2014-01-01

    If climate change outpaces the rate of adaptive evolution within a site, populations previously well adapted to local conditions may decline or disappear, and banked seeds from those populations will be unsuitable for restoring them. However, if such adaptational lag has occurred, immigrants from historically warmer climates will outperform natives and may provide genetic potential for evolutionary rescue. We tested for lagging adaptation to warming climate using banked seeds of the annual weed Arabidopsis thaliana in common garden experiments in four sites across the species’ native European range: Valencia, Spain; Norwich, United Kingdom; Halle, Germany; and Oulu, Finland. Genotypes originating from geographic regions near the planting site had high relative fitness in each site, direct evidence for broad-scale geographic adaptation in this model species. However, genotypes originating in sites historically warmer than the planting site had higher average relative fitness than local genotypes in every site, especially at the northern range limit in Finland. This result suggests that local adaptive optima have shifted rapidly with recent warming across the species’ native range. Climatic optima also differed among seasonal germination cohorts within the Norwich site, suggesting that populations occurring where summer germination is common may have greater evolutionary potential to persist under future warming. If adaptational lag has occurred over just a few decades in banked seeds of an annual species, it may be an important consideration for managing longer-lived species, as well as for attempts to conserve threatened populations through ex situ preservation. PMID:24843140

  4. Genetic mapping of adaptation reveals fitness tradeoffs in Arabidopsis thaliana.

    Science.gov (United States)

    Ågrena, Jon; Oakley, Christopher G; McKay, John K; Lovell, John T; Schemske, Douglas W

    2013-12-24

    Organisms inhabiting different environments are often locally adapted, and yet despite a considerable body of theory, the genetic basis of local adaptation is poorly understood. Unanswered questions include the number and effect sizes of adaptive loci, whether locally favored loci reduce fitness elsewhere (i.e., fitness tradeoffs), and whether a lack of genetic variation limits adaptation. To address these questions, we mapped quantitative trait loci (QTL) for total fitness in 398 recombinant inbred lines derived from a cross between locally adapted populations of the highly selfing plant Arabidopsis thaliana from Sweden and Italy and grown for 3 consecutive years at the parental sites (>40,000 plants monitored). We show that local adaptation is controlled by relatively few genomic regions of small to modest effect. A third of the 15 fitness QTL we detected showed evidence of tradeoffs, which contrasts with the minimal evidence for fitness tradeoffs found in previous studies. This difference may reflect the power of our multiyear study to distinguish conditionally neutral QTL from those that reflect fitness tradeoffs. In Sweden, but not in Italy, the local genotype underlying fitness QTL was often maladaptive, suggesting that adaptation there is constrained by a lack of adaptive genetic variation, attributable perhaps to genetic bottlenecks during postglacial colonization of Scandinavia or to recent changes in selection regime caused by climate change. Our results suggest that adaptation to markedly different environments can be achieved through changes in relatively few genomic regions, that fitness tradeoffs are common, and that lack of genetic variation can limit adaptation.

  5. Phytoremediation potential of Arabidopsis thaliana, expressing ectopically a vacuolar proton pump, for the industrial waste phosphogypsum.

    Science.gov (United States)

    Khoudi, Habib; Maatar, Yafa; Brini, Faïçal; Fourati, Amine; Ammar, Najoua; Masmoudi, Khaled

    2013-01-01

    Phosphogypsum (PG) is a by-product of the phosphorus-fertiliser industry and represents an environmental concern since it contains pollutants such as cadmium (Cd). We have recently shown that the overexpression of a proton pump gene (TaVP1) in transgenic tobacco (Nicotiana tabacum) led to an enhanced Cd tolerance and accumulation. The aim of this study was to evaluate the potential of transgenic Arabidopsis thaliana plants harbouring the TaVP1 gene to phytoremediate phosphogypsum. A pot experiment was carried out under greenhouse conditions. Transgenic A. thaliana plants harbouring the TaVP1 gene were grown on various substrates containing phosphogypsum (0, 25, 50 and 100 %) for 40 days. At the end of the growth period, we examined the growth (germination, root length, fresh weight) and physiological parameters (chlorophyll and protein contents, catalase activity and proteolysis) as well as the cadmium, Mg, Ca, and P contents of the A. thaliana plants. In order to evaluate Cd tolerance of the A. thaliana lines harbouring the TaVP1 gene, an in vitro experiment was also carried out. One week-old seedlings were transferred to Murashige and Skoog agar plates containing various concentrations of cadmium; the germination, total leaf area and root length were determined. The growth and physiological parameters of all A. thaliana plants were significantly altered by PG. The germination capacity, root growth and biomass production of wild-type (WT) plants were more severely inhibited by PG compared with the TaVP1 transgenic A. thaliana lines. In addition, TaVP1 transgenic A. thaliana plants maintained a higher antioxidant capacity than the WT. Interestingly, elemental analysis of leaf material derived from plants grown on PG revealed that the transgenic A. thaliana line accumulated up to ten times more Cd than WT. Despite its higher Cd content, the transgenic A. thaliana line performed better than the WT counterpart. In vitro evaluation of Cd tolerance showed that TaVP1

  6. Natural variation of submergence tolerance among Arabidopsis thaliana accessions

    DEFF Research Database (Denmark)

    Vashisht, D.; Hesselink, A.; Pierik, R.

    2011-01-01

    The exploitation of natural variation in Arabidopsis thaliana (Arabidopsis) provides a huge potential for the identification of the molecular mechanisms underlying this variation as a result of the availability of a vast array of genetic and genomic resources for this species. Eighty......-six Arabidopsis accessions were screened for natural variation in flooding tolerance. This forms the first step towards the identification and characterization of the role of candidate genes contributing to flooding tolerance. • Arabidopsis accessions at the 10-leaf stage were subjected to complete submergence...... in the dark. Survival curves were plotted to estimate median lethal times as a measure of tolerance. Flooding-associated survival parameters, such as root and shoot oxygen content, initial carbohydrate content and petiole elongation under water, were also measured. • There was a significant variation...

  7. Alanine aminotransferase variants conferring diverse NUE phenotypes in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Chandra H McAllister

    Full Text Available Alanine aminotransferase (AlaAT, E.C. 2.6.1.2, is a pyridoxal-5'-phosphate-dependent (PLP enzyme that catalyzes the reversible transfer of an amino group from alanine to 2-oxoglutarate to produce glutamate and pyruvate, or vice versa. It has been well documented in both greenhouse and field studies that tissue-specific over-expression of AlaAT from barley (Hordeum vulgare, HvAlaAT results in a significant increase in plant NUE in both canola and rice. While the physical phenotypes associated with over-expression of HvAlaAT have been well characterized, the role this enzyme plays in vivo to create a more N efficient plant remains unknown. Furthermore, the importance of HvAlaAT, in contrast to other AlaAT enzyme homologues in creating this phenotype has not yet been explored. To address the role of AlaAT in NUE, AlaAT variants from diverse sources and different subcellular locations, were expressed in the wild-type Arabidopsis thaliana Col-0 background and alaat1;2 (alaat1-1;alaat2-1 knockout background in various N environments. The analysis and comparison of both the physical and physiological properties of AlaAT over-expressing transgenic plants demonstrated significant differences between plants expressing the different AlaAT enzymes under different external conditions. This analysis indicates that the over-expression of AlaAT variants other than HvAlaAT in crop plants could further increase the NUE phenotype(s previously observed.

  8. Genome-scale cold stress response regulatory networks in ten Arabidopsis thaliana ecotypes

    DEFF Research Database (Denmark)

    Barah, Pankaj; Jayavelu, Naresh Doni; Rasmussen, Simon;

    2013-01-01

    ontology (GO) categories were identified to delineate natural variation of cold stress regulated differential gene expression in the model plant A. thaliana. The predicted regulatory network model was able to identify new ecotype specific transcription factors and their regulatory interactions, which might...... using Arabidopsis NimbleGen ATH6 microarrays. In total 6061 transcripts were significantly cold regulated (p expression pattern. By using sequence data...

  9. Tissue- and isoform-specific phytochrome regulation of light-dependent anthocyanin accumulation in Arabidopsis thaliana

    OpenAIRE

    2011-01-01

    Phytochromes regulate light- and sucrose-dependent anthocyanin synthesis and accumulation in many plants. Mesophyll-specific phyA alone has been linked to the regulation of anthocyanin accumulation in response to far-red light in Arabidopsis thaliana. However, multiple mesophyll-localized phytochromes were implicated in the photoregulation of anthocyanin accumulation in red-light conditions. Here, we report a role for mesophyll-specific phyA in blue-light-dependent regulation of anthocyanin l...

  10. PHENOPSIS DB: an Information System for Arabidopsis thaliana phenotypic data in an environmental context

    Directory of Open Access Journals (Sweden)

    Massonnet Catherine

    2011-05-01

    Full Text Available Abstract Background Renewed interest in plant × environment interactions has risen in the post-genomic era. In this context, high-throughput phenotyping platforms have been developed to create reproducible environmental scenarios in which the phenotypic responses of multiple genotypes can be analysed in a reproducible way. These platforms benefit hugely from the development of suitable databases for storage, sharing and analysis of the large amount of data collected. In the model plant Arabidopsis thaliana, most databases available to the scientific community contain data related to genetic and molecular biology and are characterised by an inadequacy in the description of plant developmental stages and experimental metadata such as environmental conditions. Our goal was to develop a comprehensive information system for sharing of the data collected in PHENOPSIS, an automated platform for Arabidopsis thaliana phenotyping, with the scientific community. Description PHENOPSIS DB is a publicly available (URL: http://bioweb.supagro.inra.fr/phenopsis/ information system developed for storage, browsing and sharing of online data generated by the PHENOPSIS platform and offline data collected by experimenters and experimental metadata. It provides modules coupled to a Web interface for (i the visualisation of environmental data of an experiment, (ii the visualisation and statistical analysis of phenotypic data, and (iii the analysis of Arabidopsis thaliana plant images. Conclusions Firstly, data stored in the PHENOPSIS DB are of interest to the Arabidopsis thaliana community, particularly in allowing phenotypic meta-analyses directly linked to environmental conditions on which publications are still scarce. Secondly, data or image analysis modules can be downloaded from the Web interface for direct usage or as the basis for modifications according to new requirements. Finally, the structure of PHENOPSIS DB provides a useful template for the development

  11. Two kinesin-like proteins mediate actin-based chloroplast movement in Arabidopsis thaliana

    OpenAIRE

    Suetsugu, Noriyuki; Yamada, Noboru; Kagawa, Takatoshi; Yonekura, Hisashi; Uyeda, Taro Q. P.; Kadota, Akeo; Wada, Masamitsu

    2010-01-01

    Organelle movement is essential for efficient cellular function in eukaryotes. Chloroplast photorelocation movement is important for plant survival as well as for efficient photosynthesis. Chloroplast movement generally is actin dependent and mediated by blue light receptor phototropins. In Arabidopsis thaliana, phototropins mediate chloroplast movement by regulating short actin filaments on chloroplasts (cp-actin filaments), and the chloroplast outer envelope protein CHUP1 is necessary for c...

  12. Three-Dimensional Structure of Arabidopsis thaliana Lipase Predicted by Homology Modeling Method

    OpenAIRE

    2011-01-01

    Triacylglycerol lipases have been thoroughly characterized in mammals and microorganisms. By contrast, very little is known about plant lipases. In this investigation, a homology model of Arabidopsis thaliana lipase (NP_179126) was constructed using a human gastric lipase (PDB ID: 1HLG), as a template for model building. This model was then assessed for stereochemical quality and side chain environment. Natural substrates: tributyrin, trioctanoin and triolen were docked into the model to inve...

  13. An ANN-GA model based promoter prediction in Arabidopsis thaliana using tilling microarray data

    OpenAIRE

    Mishra, Hrishikesh; Singh, Nitya; Misra, Krishna; Lahiri, Tapobrata

    2011-01-01

    Identification of promoter region is an important part of gene annotation. Identification of promoters in eukaryotes is important as promoters modulate various metabolic functions and cellular stress responses. In this work, a novel approach utilizing intensity values of tilling microarray data for a model eukaryotic plant Arabidopsis thaliana, was used to specify promoter region from non-promoter region. A feed-forward back propagation neural network model supported by genetic algorithm was ...

  14. Phytotoxicity of chiral herbicide bromacil: Enantioselectivity of photosynthesis in Arabidopsis thaliana

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Zunwei; Zou, Yuqin; Wang, Jia [MOE Key Laboratory of Environmental Remediation & Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China); Li, Meichao [Research Center of Analysis and Measurement, Zhejiang University of Technology, Hangzhou 310032 (China); Wen, Yuezhong, E-mail: wenyuezhong@zju.edu.cn [MOE Key Laboratory of Environmental Remediation & Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China)

    2016-04-01

    With the wide application of chiral herbicides and the frequent detection of photosystem II (PSII) herbicides, it is of great importance to assess the direct effects of PSII herbicides on photosynthesis in an enantiomeric level. In the present study, the enantioselective phytotoxicity of bromacil (BRO), typical photosynthesis inhibition herbicide, on Arabidopsis thaliana was investigated. The results showed that S-BRO exhibited a greater inhibition of electron transmission in photosystem I (PSI) of A. thaliana than R-BRO by inhibiting the transcription of fnr 1. S-BRO also changed the chlorophyll fluorescence parameters Y (II), Y (NO), and Y (NPQ) to a greater extent than R-Bro. Transcription of genes psbO2, Lhcb3 and Lhcb6 was down-regulated in an enantioselective rhythm and S-BRO caused more serious influence, indicating that S-BRO did worse damage to the photosystem II (PSII) of A. thaliana than R-BRO. This study suggested that S-BRO disturbed the photosynthesis of plants to a larger extent than R-BRO and provided a new sight to evaluate the phytotoxicity of chiral herbicides. - Highlights: • It is necessary to assess the direct effects of PSII herbicides on photosynthesis. • Phytotoxicity of bromacil is investigated in an enantiomeric level. • Bromacil disturbed enantioselectively the photosystem II of Arabidopsis thaliana. • S-bromacil caused severer damage to photosynthesis of Arabidopsis than R-bromacil. • Photosynthesis should be considered for phytotoxicity assessment of herbicides.

  15. Expression of NO scavenging hemoglobin is involved in the timing of bolting in Arabidopsis thaliana

    DEFF Research Database (Denmark)

    Hebelstrup, Kim Henrik; Jensen, Erik Østergaard

    2008-01-01

    -symbiotic hemoglobin gene, GLB2, in Arabidopsis thaliana. Lines with GLB1 silencing had a significant delay of bolting and after bolting, shoots reverted to the rosette vegetative phase by formation of aerial rosettes at lateral meristems. Lines with overexpression of GLB1 or GLB2 bolted earlier than wild type plants...... molecule, NO. So far, NO scavenging has only been demonstrated for class 1 non-symbiotic hemoglobins. A direct assay in Arabidopsis leaf cells shows that GLB1 as well as the class 2 non-symbiotic hemoglobin, GLB2, scavenge NO in vivo. NO has also been demonstrated to be a growth stimulating signal...

  16. Verification at the protein level of the PIF4-mediated external coincidence model for the temperature-adaptive photoperiodic control of plant growth in Arabidopsis thaliana.

    Science.gov (United States)

    Yamashino, Takafumi; Nomoto, Yuji; Lorrain, Séverine; Miyachi, Miki; Ito, Shogo; Nakamichi, Norihito; Fankhauser, Christian; Mizuno, Takeshi

    2013-03-01

    Plant circadian clock controls a wide variety of physiological and developmental events, which include the short-days (SDs)-specific promotion of the elongation of hypocotyls during de-etiolation and also the elongation of petioles during vegetative growth. In A. thaliana, the PIF4 gene encoding a phytochrome-interacting basic helix-loop-helix (bHLH) transcription factor plays crucial roles in this photoperiodic control of plant growth. According to the proposed external coincidence model, the PIF4 gene is transcribed precociously at the end of night specifically in SDs, under which conditions the protein product is stably accumulated, while PIF4 is expressed exclusively during the daytime in long days (LDs), under which conditions the protein product is degraded by the light-activated phyB and also the residual proteins are inactivated by the DELLA family of proteins. A number of previous reports provided solid evidence to support this coincidence model mainly at the transcriptional level of the PIF 4 and PIF4-traget genes. Nevertheless, the diurnal oscillation profiles of PIF4 proteins, which were postulated to be dependent on photoperiod and ambient temperature, have not yet been demonstrated. Here we present such crucial evidence on PIF4 protein level to further support the external coincidence model underlying the temperature-adaptive photoperiodic control of plant growth in A. thaliana.

  17. Mining the active proteome of Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Renier A. L. Van Der Hoorn

    2011-11-01

    Full Text Available Assigning functions to the >30.000 proteins encoded by the Arabidopsis genome is a challenging task of the Arabidopsis Functional Genomics Network. Although genome-wide technologies like proteomics and transcriptomics have generated a wealth of information that significantly accelerated gene annotation, protein activities are poorly predicted by transcript or protein levels as protein activities are post-translationally regulated. To directly display protein activities in Arabidopsis proteomes, we developed and applied Activity-based Protein Profiling (ABPP. ABPP is based on the use of small molecule probes that react with the catalytic residues of distinct protein classes in an activity-dependent manner. Labeled proteins are separated and detected from proteins gels and purified and identified by mass spectrometry. Using probes of six different chemotypes we have displayed of activities of 76 Arabidopsis proteins. These proteins represent over ten different protein classes that contain over 250 Arabidopsis proteins, including cysteine- serine- and metallo-proteases, lipases, acyltransferases, and the proteasome. We have developed methods for identification of in vivo labeled proteins using click-chemistry and for in vivo imaging with fluorescent probes. In vivo labeling has revealed novel protein activities and unexpected subcellular activities of the proteasome. Labeling of extracts displayed several differential activities e.g. of the proteasome during immune response and methylesterases during infection. These studies illustrate the power of ABPP to display the functional proteome and testify to a successful interdisciplinary collaboration involving chemical biology, organic chemistry and proteomics.

  18. An aeroponic culture system for the study of root herbivory on Arabidopsis thaliana

    Science.gov (United States)

    2011-01-01

    Background Plant defense against herbivory has been studied primarily in aerial tissues. However, complex defense mechanisms have evolved in all parts of the plant to combat herbivore attack and these mechanisms are likely to differ in the aerial and subterranean environment. Research investigating defense responses belowground has been hindered by experimental difficulties associated with the accessibility and quality of root tissue and the lack of bioassays using model plants with altered defense profiles. Results We have developed an aeroponic culture system based on a calcined clay substrate that allows insect herbivores to feed on plant roots while providing easy recovery of the root tissue. The culture method was validated by a root-herbivore system developed for Arabidopsis thaliana and the herbivore Bradysia spp. (fungus gnat). Arabidopsis root mass obtained from aeroponically grown plants was comparable to that from other culture systems, and the plants were morphologically normal. Bradysia larvae caused considerable root damage resulting in reduced root biomass and water absorption. After feeding on the aeroponically grown root tissue, the larvae pupated and emerged as adults. Root damage of mature plants cultivated in aeroponic substrate was compared to that of Arabidopsis seedlings grown in potting mix. Seedlings were notably more susceptible to Bradysia feeding than mature plants and showed decreased overall growth and survival rates. Conclusions A root-herbivore system consisting of Arabidopsis thaliana and larvae of the opportunistic herbivore Bradysia spp. has been established that mimics herbivory in the rhizosphere. Bradysia infestation of Arabidopsis grown in this culture system significantly affects plant performance. The culture method will allow simple profiling and in vivo functional analysis of root defenses such as chemical defense metabolites that are released in response to belowground insect attack. PMID:21392399

  19. PHH1, a novel gene from Arabidopsis thaliana that encodes a protein similar to plant blue-light photoreceptors and microbial photolyases.

    Science.gov (United States)

    Hoffman, P D; Batschauer, A; Hays, J B

    1996-11-27

    A cDNA from Arabidopsis thaliana similar to microbial photolyase genes, and designated AT-PHH1, was isolated using a photolyase-like cDNA from Sinapsis alba (SA-PHR1) as a probe. Multiple isolations yielded only PHH1 cDNAs, and a few blue-light-receptor CRY1 (HY4) cDNAs (also similar to microbial photolyase genes), suggesting the absence of any other highly similar Arabidopsis genes. The AT-PHH1 and SA-PHR1 cDNA sequences predict 89% identity at the protein level, except for an AT-PHH1 C-terminal extension (111 amino acids), also not seen in microbial photolyases. AT-PHH1 and CRY1 show less similarity (54% p4erein identity), including respective C-terminal extensions that are themselves mostly dissimilar. Analysis of fifteen AT-PHH1 genomic isolates reveals a single gene, with three introns in the coding sequence and one in the 5'-untranslated leader. Full-length AT-PHH1, and both AT-PHH1 and AT-PHH1 delta C-513 (truncated to be approximately the size of microbial photolyase genes) cDNAs, were overexpressed, respectively, in yeast and Escherichia coli mutants hypersensitive to ultraviolet light. The absence of significant effects on resistance suggests either that any putative AT-PHH1 DNA repair activity requires cofactors/chromophores not present in yeast or E. coli, or that AT-PHH1 encodes a blue-light/ultraviolet-A receptor rather than a DNA repair protein.

  20. Growth enhancement and gene expression of Arabidopsis thaliana irradiated with active oxygen species

    Science.gov (United States)

    Watanabe, Satoshi; Ono, Reoto; Hayashi, Nobuya; Shiratani, Masaharu; Tashiro, Kosuke; Kuhara, Satoru; Inoue, Asami; Yasuda, Kaori; Hagiwara, Hiroko

    2016-07-01

    The characteristics of plant growth enhancement effect and the mechanism of the enhancement induced by plasma irradiation are investigated using various active species in plasma. Active oxygen species in oxygen plasma are effective for growth enhancement of plants. DNA microarray analysis of Arabidopsis thaliana indicates that the genes coding proteins that counter oxidative stresses by eliminating active oxygen species are expressed at significantly high levels. The size of plant cells increases owing to oxygen plasma irradiation. The increases in gene expression levels and cell size suggest that the increase in the expression level of the expansin protein is essential for plant growth enhancement phenomena.

  1. Arabidopsis thaliana dehydroascorbate reductase 2: Conformational flexibility during catalysis

    Science.gov (United States)

    Bodra, Nandita; Young, David; Astolfi Rosado, Leonardo; Pallo, Anna; Wahni, Khadija; de Proft, Frank; Huang, Jingjing; van Breusegem, Frank; Messens, Joris

    2017-02-01

    Dehydroascorbate reductase (DHAR) catalyzes the glutathione (GSH)-dependent reduction of dehydroascorbate and plays a direct role in regenerating ascorbic acid, an essential plant antioxidant vital for defense against oxidative stress. DHAR enzymes bear close structural homology to the glutathione transferase (GST) superfamily of enzymes and contain the same active site motif, but most GSTs do not exhibit DHAR activity. The presence of a cysteine at the active site is essential for the catalytic functioning of DHAR, as mutation of this cysteine abolishes the activity. Here we present the crystal structure of DHAR2 from Arabidopsis thaliana with GSH bound to the catalytic cysteine. This structure reveals localized conformational differences around the active site which distinguishes the GSH-bound DHAR2 structure from that of DHAR1. We also unraveled the enzymatic step in which DHAR releases oxidized glutathione (GSSG). To consolidate our structural and kinetic findings, we investigated potential conformational flexibility in DHAR2 by normal mode analysis and found that subdomain mobility could be linked to GSH binding or GSSG release.

  2. Arabidopsis thaliana dehydroascorbate reductase 2: Conformational flexibility during catalysis

    Science.gov (United States)

    Bodra, Nandita; Young, David; Astolfi Rosado, Leonardo; Pallo, Anna; Wahni, Khadija; De Proft, Frank; Huang, Jingjing; Van Breusegem, Frank; Messens, Joris

    2017-01-01

    Dehydroascorbate reductase (DHAR) catalyzes the glutathione (GSH)-dependent reduction of dehydroascorbate and plays a direct role in regenerating ascorbic acid, an essential plant antioxidant vital for defense against oxidative stress. DHAR enzymes bear close structural homology to the glutathione transferase (GST) superfamily of enzymes and contain the same active site motif, but most GSTs do not exhibit DHAR activity. The presence of a cysteine at the active site is essential for the catalytic functioning of DHAR, as mutation of this cysteine abolishes the activity. Here we present the crystal structure of DHAR2 from Arabidopsis thaliana with GSH bound to the catalytic cysteine. This structure reveals localized conformational differences around the active site which distinguishes the GSH-bound DHAR2 structure from that of DHAR1. We also unraveled the enzymatic step in which DHAR releases oxidized glutathione (GSSG). To consolidate our structural and kinetic findings, we investigated potential conformational flexibility in DHAR2 by normal mode analysis and found that subdomain mobility could be linked to GSH binding or GSSG release. PMID:28195196

  3. Proteomic analyses of apoplastic proteins from germinating Arabidopsis thaliana pollen.

    Science.gov (United States)

    Ge, Weina; Song, Yun; Zhang, Cuijun; Zhang, Yafang; Burlingame, Alma L; Guo, Yi

    2011-12-01

    Pollen grains play important roles in the reproductive processes of flowering plants. The roles of apoplastic proteins in pollen germination and in pollen tube growth are comparatively less well understood. To investigate the functions of apoplastic proteins in pollen germination, the global apoplastic proteins of mature and germinated Arabidopsis thaliana pollen grains were prepared for differential analyses by using 2-dimensional fluorescence difference gel electrophoresis (2-D DIGE) saturation labeling techniques. One hundred and three proteins differentially expressed (p value≤0.01) in pollen germinated for 6h compared with un-germination mature pollen, and 98 spots, which represented 71 proteins, were identified by LC-MS/MS. By bioinformatics analysis, 50 proteins were identified as secreted proteins. These proteins were mainly involved in cell wall modification and remodeling, protein metabolism and signal transduction. Three of the differentially expressed proteins were randomly selected to determine their subcellular localizations by transiently expressing YFP fusion proteins. The results of subcellular localization were identical with the bioinformatics prediction. Based on these data, we proposed a model for apoplastic proteins functioning in pollen germination and pollen tube growth. These results will lead to a better understanding of the mechanisms of pollen germination and pollen tube growth.

  4. Tungsten disrupts root growth in Arabidopsis thaliana by PIN targeting.

    Science.gov (United States)

    Adamakis, Ioannis-Dimosthenis S; Panteris, Emmanuel; Eleftheriou, Eleftherios P

    2014-08-15

    Tungsten is a heavy metal with increasing concern over its environmental impact. In plants it is extensively used to deplete nitric oxide by inhibiting nitrate reductase, but its presumed toxicity as a heavy metal has been less explored. Accordingly, its effects on Arabidopsis thaliana primary root were assessed. The effects on root growth, mitotic cell percentage, nitric oxide and hydrogen peroxide levels, the cytoskeleton, cell ultrastructure, auxin and cytokinin activity, and auxin carrier distribution were investigated. It was found that tungsten reduced root growth, particularly by inhibiting cell expansion in the elongation zone, so that root hairs emerged closer to the root tip than in the control. Although extensive vacuolation was observed, even in meristematic cells, cell organelles were almost unaffected and microtubules were not depolymerized but reoriented. Tungsten affected auxin and cytokinin activity, as visualized by the DR5-GFP and TCS-GFP expressing lines, respectively. Cytokinin fluctuations were similar to those of the mitotic cell percentage. DR5-GFP signal appeared ectopically expressed, while the signals of PIN2-GFP and PIN3-GFP were diminished even after relatively short exposures. The observed effects were not reminiscent of those of any nitric oxide scavengers. Taken together, inhibition of root growth by tungsten might rather be related to a presumed interference with the basipetal flow of auxin, specifically affecting cell expansion in the elongation zone.

  5. Differential responses to salt-induced oxidative stress in three phylogenetically related plant species: Arabidopsis thaliana (glycophyte, Thellungiella salsuginea and Cakile maritima (halophytes. Involvement of ROS and NO in the control of K+/Na+ homeostasis

    Directory of Open Access Journals (Sweden)

    Francisco J Corpas

    2016-08-01

    Full Text Available Salinity, which is usually associated with a nitro-oxidative stress component, is one of the major environmental factors limiting plant growth and development. Plants have thus developed specific ways of dealing with this problem. The compartmentalization of sodium (Na+ ions in vacuoles and the capacity to sharply discriminate between potassium (K+ and Na+ in order to maintain high K+/Na+ ratios are two of the most effective strategies to overcome salt stress. Plants require large amounts of K+ to maximize growth and yields. This macronutrient is involved in physiological processes such as growth, photosynthesis, osmoregulation, enzyme activation, stomatal movement, water and nutrient transport via the xylem and protein synthesis. Resistance to salt stress is mainly related to the capacity of plants to maintain improved K+ uptake despite competition from Na+. The Brassicaceae family includes species such as Arabidopsis thaliana (plant model for glycophytes, Thellungiella salsuginea and Cakile maritima (plant models for halophytes, which exhibit significant variations in response to salt stress. In this review, we provide a comprehensive update with respect to differential responses to salt stress in these three plant species, with particular emphasis on the potential involvement of reactive oxygen species (ROS and nitric oxide (NO in maintaining K+/Na+ homeostasis and their contribution to salt tolerance.

  6. Purification, crystallization and preliminary crystallographic analysis of deoxyuridine triphosphate nucleotidohydrolase from Arabidopsis thaliana

    Energy Technology Data Exchange (ETDEWEB)

    Bajaj, Mamta [School of Biological Sciences, University of Nebraska-Lincoln, Manter Hall, Lincoln, Nebraska 68588-0304 (United States); Moriyama, Hideaki, E-mail: hmoriyama2@unl.edu [Department of Chemistry, e-Toxicology and Biotechnology, University of Nebraska-Lincoln, Hamilton Hall, Lincoln, Nebraska 68588-0304 (United States); School of Biological Sciences, University of Nebraska-Lincoln, Manter Hall, Lincoln, Nebraska 68588-0304 (United States)

    2007-05-01

    The first crystallization of deoxyuridine triphosphate nucleotidohydrolase from plant, Arabidopsis thaliana, has been performed. An additive, taurine, was effective in producing the single crystal. The deoxyuridine triphosphate nucleotidohydrolase gene from Arabidopsis thaliana was expressed and the gene product was purified. Crystallization was performed by the hanging-drop vapour-diffusion method at 298 K using 2 M ammonium sulfate as the precipitant. X-ray diffraction data were collected to 2.2 Å resolution using Cu Kα radiation. The crystal belongs to the orthorhombic space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 69.90, b = 70.86 Å, c = 75.55 Å. Assuming the presence of a trimer in the asymmetric unit, the solvent content was 30%, with a V{sub M} of 1.8 Å{sup 3} Da{sup −1}.

  7. Properties of serine: glyoxylate aminotransferase purified from Arabidopsis thaliana leaves

    Institute of Scientific and Technical Information of China (English)

    Maria Kendziorek; Andrzej Paszkowski

    2008-01-01

    The photorespiratory enzyme L-serine: glyoxylate aminotransferase (SGAT; EC 2.6.1.45) was purified from Arabidopsis thaliana leaves. The final enzyme was approximately 80% pure as revealed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis with silver staining. The identity of the enzyme was confirmed by LC/MS/MS analysis.The molecular mass estimated by gel filtration chromatography on Sephadex G-150 under non-denaturing conditions, mass spectrometry (matrix-assisted laser desorption/ionization/time of flight technique) and sodium dodecyl sulfate-polyacrylamide gel electrophoresis was 82.4 kDa,42.0 kDa, and 39.8 kDa, respectively, indicating dimer as the active form. The optimum Ph value was 9.2. The enzyme activity was inhibited by aminooxyacetate and β-chloro-L-alanine both compounds reacting with the carbonyl group of pyridoxal phosphate. The enzyme's transaminating activity with L-alanine and glyoxylate as substrates was approximately 55% of that observed with L-serine and glyoxylate, The lower Km value (1.25 Mm) for L-alanine, compared with that of other plant SGATs, and the kcat/Km(Ala) ratio being approximately 2-fold higher than kcat/Km(Ser) suggested that, during photorespiration, Ala and Ser are used by Arabidopsis SGAT with equal efficiency as amino group donors for glyoxylate. The equilibrium constant (Keq), derived from the Haldane relation, for the transamination reaction between L-serine and glyoxylate with the formation of hydroxypyruvate and glycine was 79.1, strongly favoring glycine synthesis. However, it was accompanied by a low Km value of 2.83 Mm for glycine. A comparison of some kinetic properties of the studied enzymes with the recombinant Arabidopsis SGATs previously obtained revealed substantial differences. The ratio of the velocity of the transamination reaction with L-alanine and glyoxylate as substrates versus that with L-serine and glyoxylate was 1:1.8 for the native enzyme, whereas it was 1: 7 for the recombinant SGAT

  8. Positive regulatory role of sound vibration treatment in Arabidopsis thaliana against Botrytis cinerea infection.

    Science.gov (United States)

    Choi, Bosung; Ghosh, Ritesh; Gururani, Mayank Anand; Shanmugam, Gnanendra; Jeon, Junhyun; Kim, Jonggeun; Park, Soo-Chul; Jeong, Mi-Jeong; Han, Kyung-Hwan; Bae, Dong-Won; Bae, Hanhong

    2017-05-30

    Sound vibration (SV), a mechanical stimulus, can trigger various molecular and physiological changes in plants like gene expression, hormonal modulation, induced antioxidant activity and calcium spiking. It also alters the seed germination and growth of plants. In this study, we investigated the effects of SV on the resistance of Arabidopsis thaliana against Botrytis cinerea infection. The microarray analysis was performed on infected Arabidopsis plants pre-exposed to SV of 1000 Hertz with 100 decibels. Broadly, the transcriptomic analysis revealed up-regulation of several defense and SA-responsive and/or signaling genes. Quantitative real-time PCR (qRT-PCR) analysis of selected genes also validated the induction of SA-mediated response in the infected Arabidopsis plants pre-exposed to SV. Corroboratively, hormonal analysis identified the increased concentration of salicylic acid (SA) in the SV-treated plants after pathogen inoculation. In contrast, jasmonic acid (JA) level in the SV-treated plants remained stable but lower than control plants during the infection. Based on these findings, we propose that SV treatment invigorates the plant defense system by regulating the SA-mediated priming effect, consequently promoting the SV-induced resistance in Arabidopsis against B. cinerea.

  9. AtbHLH29 of Arabidopsis thaliana is a functional ortholog of tomato FER involved in controlling iron acquisition in strategy I plants

    Institute of Scientific and Technical Information of China (English)

    You Xi YUAN; Juan ZHANG; Dao Wen WANG; Hong Qing LING

    2005-01-01

    AtbHLH29 of Arabidopsis, encoding a bHLH protein, reveals a high similarity to the tomato FER which is proposed as a transcriptional regulator involved in controlling the iron deficiency responses and the iron uptake in tomato. For identification of its biological functions, AtbHLH29 was introduced into the genome of the tomato FER mutant T3238fer mediated by Agrobacterium tumefaciencs. Transgenic plants were regenerated and the stable integration of AtbHLH29 into their genomes was confirmed by Southern hybridization. Molecular analysis demonstrated that expression of the exogenous AtbHLH29 of Arabidopsis in roots of the FER mutant T3238fer enabled to complement the defect functions of FER. The transgenic plants regained the ability to activate the whole iron deficiency responses and showed normal growth as the wild type under iron-limiting stress. Our transformation data demonstrate that AtbHLH29 is a functional ortholog of the tomato FER and can completely replace FER in controlling the effective iron acquisition in tomato.Except of iron, FER protein was directly or indirectly involved in manganese homeostasis due to that loss functions of FER in T3238fer resulted in strong reduction of Mn content in leaves and the defect function on Mn accumulation in leaves was complemented by expression of AtbHLH29 in the transgenic plants. Identification of the similar biological functions of FER and AtbHLH29, which isolated from two systematically wide-diverged "strategy I" plants, suggests that FER might be a universal gene presented in all strategy I plants in controlling effective iron acquisition system in roots.

  10. AtbHLH29 of Arabidopsis thaliana is a functional ortholog of tomato FER involved in controlling iron acquisition in strategy I plants.

    Science.gov (United States)

    Yuan, You Xi; Zhang, Juan; Wang, Dao Wen; Ling, Hong Qing

    2005-08-01

    AtbHLH29 of Arabidopsis, encoding a bHLH protein, reveals a high similarity to the tomato FER which is proposed as a transcriptional regulator involved in controlling the iron deficiency responses and the iron uptake in tomato. For identification of its biological functions, AtbHLH29 was introduced into the genome of the tomato FER mutant T3238fer mediated by Agrobacterium tumefaciencs. Transgenic plants were regenerated and the stable integration of AtbHLH29 into their genomes was confirmed by Southern hybridization. Molecular analysis demonstrated that expression of the exogenous AtbHLH29 of Arabidopsis in roots of the FER mutant T3238fer enabled to complement the defect functions of FER. The transgenic plants regained the ability to activate the whole iron deficiency responses and showed normal growth as the wild type under iron-limiting stress. Our transformation data demonstrate that AtbHLH29 is a functional ortholog of the tomato FER and can completely replace FER in controlling the effective iron acquisition in tomato. Except of iron, FER protein was directly or indirectly involved in manganese homeostasis due to that loss functions of FER in T3238fer resulted in strong reduction of Mn content in leaves and the defect function on Mn accumulation in leaves was complemented by expression of AtbHLH29 in the transgenic plants. Identification of the similar biological functions of FER and AtbHLH29, which isolated from two systematically wide-diverged "strategy I" plants, suggests that FER might be a universal gene presented in all strategy I plants in controlling effective iron acquisition system in roots.

  11. In vivo protein tyrosine nitration in Arabidopsis thaliana

    Science.gov (United States)

    Lozano-Juste, Jorge; Colom-Moreno, Rosa; León, José

    2011-01-01

    Nitration of tyrosine (Y) residues of proteins is a low abundant post-translational modification that modulates protein function or fate in animal systems. However, very little is known about the in vivo prevalence of this modification and its corresponding targets in plants. Immunoprecipitation, based on an anti-3-nitroY antibody, was performed to pull-down potential in vivo targets of Y nitration in the Arabidopsis thaliana proteome. Further shotgun liquid chromatography–mass spectrometry (LC-MS/MS) proteomic analysis of the immunoprecipitated proteins allowed the identification of 127 proteins. Around 35% of them corresponded to homologues of proteins that have been previously reported to be Y nitrated in other non-plant organisms. Some of the putative in vivo Y-nitrated proteins were further confirmed by western blot with specific antibodies. Furthermore, MALDI-TOF (matrix-assisted laser desorption ionization-time of flight) analysis of protein spots, separated by two-dimensional electrophoresis from immunoprecipitated proteins, led to the identification of seven nitrated peptides corresponding to six different proteins. However, in vivo nitration sites among putative targets could not be identified by MS/MS. Nevertheless, an MS/MS spectrum with 3-aminoY318 instead of the expected 3-nitroY was found for cytosolic glyceraldehyde-3-phosphate dehydrogenase. Reduction of nitroY to aminoY during MS-based proteomic analysis together with the in vivo low abundance of these modifications made the identification of nitration sites difficult. In turn, in vitro nitration of methionine synthase, which was also found in the shotgun proteomic screening, allowed unequivocal identification of a nitration site at Y287. PMID:21378116

  12. Effect of clinorotation on the leaf mesophyll structure and pigment content in Arabidopsis thaliana L. and Pisum sativum L.

    Science.gov (United States)

    Adamchuk, N I

    2004-07-01

    Properties of mesophyll cells and photosynthetic membranes of Arabidopsis thaliana (L.) Heynh. and Pisum sativum (L.) plants grown in a horizontal clinostat and in control conditions were compared. Obtained data have show that under clinorotation conditions seedlings have experienced the following cell morphology changes structural chloroplast rearrangement in palisade cells, pigment content alteration, and cell aging acceleration.

  13. Root hair defective4 encodes a phosphatidylinositol-4-phosphate phosphatase required for proper root hair development in Arabidopsis thaliana

    NARCIS (Netherlands)

    Thole, J.M.; Vermeer, J.E.M.; Zhang, Y.; Gadella, Th.W.J.; Nielsen, E.

    2008-01-01

    Polarized expansion of root hair cells in Arabidopsis thaliana is improperly controlled in root hair-defective rhd4-1 mutant plants, resulting in root hairs that are shorter and randomly form bulges along their length. Using time-lapse fluorescence microscopy in rhd4-1 root hairs, we analyzed

  14. Arabidopsis thaliana Somatic Embryogenesis Receptor Kinase I protein is present in sporophytic and gametophytic cells and undergoes endocytosis

    NARCIS (Netherlands)

    Kwaaitaal, M.A.C.J.; Vries, de S.C.; Russinova, E.T.

    2005-01-01

    Arabidopsis thaliana plants expressing AtSERK1 fused to yellow-fluorescent protein were generated. Fluorescence was detected predominantly at the cell periphery, most likely the plasma membrane, of cells in ovules, embryo sacs, anthers, and embryos and in seedlings. The AtSERK1 protein was detected

  15. MADS on the move : a study on MADS domain protein function and movement during floral development in Arabidopsis thaliana

    NARCIS (Netherlands)

    Urbanus, S.L.

    2010-01-01

    In this thesis we investigated the behaviour of fluorescently-tagged MADS domain proteins during floral development in the model plant Arabidopsis thaliana, and explored the importance of intercellular transport via plasmodesmata for MADS domain transcription factor functioning. The MADS domain tran

  16. A novel role for methyl cysteinate, a cysteine derivative, in cesium accumulation in Arabidopsis thaliana

    Science.gov (United States)

    Adams, Eri; Miyazaki, Takae; Hayaishi-Satoh, Aya; Han, Minwoo; Kusano, Miyako; Khandelia, Himanshu; Saito, Kazuki; Shin, Ryoung

    2017-01-01

    Phytoaccumulation is a technique to extract metals from soil utilising ability of plants. Cesium is a valuable metal while radioactive isotopes of cesium can be hazardous. In order to establish a more efficient phytoaccumulation system, small molecules which promote plants to accumulate cesium were investigated. Through chemical library screening, 14 chemicals were isolated as ‘cesium accumulators’ in Arabidopsis thaliana. Of those, methyl cysteinate, a derivative of cysteine, was found to function within the plant to accumulate externally supplemented cesium. Moreover, metabolite profiling demonstrated that cesium treatment increased cysteine levels in Arabidopsis. The cesium accumulation effect was not observed for other cysteine derivatives or amino acids on the cysteine metabolic pathway tested. Our results suggest that methyl cysteinate, potentially metabolised from cysteine, binds with cesium on the surface of the roots or inside plant cells and improve phytoaccumulation. PMID:28230101

  17. The development of Arabidopsis as a plant model

    NARCIS (Netherlands)

    Koornneef, M.; Meinke, D.W.

    2010-01-01

    Twenty-five years ago, Arabidopsis thaliana emerged as the model organism of choice for research in plant biology. A consensus was reached about the need to focus on a single organism to integrate the classical disciplines of plant science with the expanding fields of genetics and molecular biology.

  18. The fate of retrotransposed processed genes in Arabidopsis thaliana.

    Science.gov (United States)

    Abdelkarim, Basma T M; Maranda, Vincent; Drouin, Guy

    2017-04-20

    Processed genes are functional genes that have arisen as a result of the retrotransposition of mRNA molecules. We found 6 genes that generated processed genes in the common ancestor of five Brassicaceae species (Arabidopsis thaliana, Arabidopsis lyrata, Capsella rubella, Brassica rapa and Thellungiella parvula). These processed genes have therefore been kept for at least 30millionyears. Analyses of the Ka/Ks ratio of these genes, and of those having given rise to them, show that they evolve relatively slowly and suggest that the processed genes maintained the same function as that of their parental gene. There is a significant negative correlation between the number of ESTs and transcripts produced and the Ka/Ks ratios of the parental genes but not of the processed genes. This suggests that selection has not yet adapted the selective pressure the processed genes experience to their expression level. However, the A. thaliana processed genes tend to be expressed in the same tissues as that of their parental genes. Furthermore, most have a CAATT-box, a TATA-box and are located about 1kb from another protein-coding gene. Altogether, our results suggest that the processed genes found in the A. thaliana genome have been kept to produce more of the same product, and in the same tissues, as that encoded by their parental gene. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

  19. The Arabidopsis thaliana aleurone layer responds to nitric oxide, gibberellin, and abscisic acid and is sufficient and necessary for seed dormancy

    Science.gov (United States)

    Seed dormancy is a common phase of the plant life cycle and several parts of the seed can contribute to dormancy. Whole seeds, seeds lacking the testa, embryos, and isolated aleurone layers of Arabidopsis thaliana were used in experiments designed to identify components of the arabidopsis seed that ...

  20. Evaluation of Seed Transmission of Turnip yellow mosaic virus and Tobacco mosaic virus in Arabidopsis thaliana.

    Science.gov (United States)

    de Assis Filho, F M; Sherwood, J L

    2000-11-01

    ABSTRACT The mechanism of virus transmission through seed was studied in Arabidopsis thaliana infected with Turnip yellow mosaic virus (TYMV) and Tobacco mosaic virus (TMV). Serological and biological tests were conducted to identify the route by which the viruses reach the seed and subsequently are located in the seed. Both TYMV and TMV were detected in seed from infected plants, however only TYMV was seed-transmitted. This is the first report of transmission of TYMV in seed of A. thaliana. Estimating virus seed transmission by grow-out tests was more accurate than enzyme-linked immunosorbent assay due to the higher frequency of antigen in the seed coat than in the embryo. Virus in the seed coat did not lead to seedling infection. Thus, embryo invasion is necessary for seed transmission of TYMV in A. thaliana. Crosses between healthy and virus-infected plants indicated that TYMV from either the female or the male parent could invade the seed. Conversely, invasion from maternal tissue was the only route for TMV to invade the seed. Pollination of flowers on healthy A. thaliana with pollen from TYMV-infected plants did not result in systemic infection of healthy plants, despite TYMV being carried by pollen to the seed.

  1. Increase in recombination rate in Arabidopsis thaliana plants sharing gaseous environment with X-ray and UVC-irradiated plants depends on production of radicals.

    Science.gov (United States)

    Zemp, Franz J; Sidler, Corinne; Kovalchuk, Igor

    2012-07-01

    X-ray and UVC are the two physical agents that damage DNA directly, with both agents capable of inducing double-strand breaks. Some of our recent work has demonstrated that local exposure to UVC results in a systemic increase in recombination frequency, suggesting that information about exposure can be passed from damaged to non-damaged tissue. Indeed, we recently showed that plants sharing the same enclosed environment with UVC-irradiated plants exhibit similar increase in homologous recombination frequency as irradiated plants. Here, we further tested whether yet another DNA-damaging agent, X-ray, is capable of increasing recombination rate (RR) in neighboring plants grown in a Petri dish. To test this, we grew plants exposed to X-ray or UVC irradiation in an enclosed environment next to non-exposed plants. We found that both X-ray and UVC-irradiated plants and neighboring plants exhibited comparable increases in the levels of strand breaks and the RR. We further showed that pre-exposure of plants to radical scavenger DMSO substantially alleviates the radiation-induced increase in RR and prevents formation of bystander signal. Our results suggest that the increase in RR in bystander plants can also be triggered by X-ray and that radicals may play some role in initiation or maintenance of this signal.

  2. Isolation of T—DNA flanking plant DNA from T—DNA insertional embryo—lethal mutants of Arabidopsis thaliana by plasmid rescue technique

    Institute of Scientific and Technical Information of China (English)

    YAOXIAOLI; JIANGESUN; 等

    1996-01-01

    Three T-DNA insertional embryonic lethal mutants from NASC(The Nottingham Arabidopsis Stock Center) were first checked with their segregation ratio of abortive and normal seeds and the copy number of T-DNA insertion.The N4081 mutant has a segregation ratio of 1:3.04 in average and one T-DNA insertion site according to our assay.It was therefore chosen for further analysis.To isolate the joint fragment of T-DNA and plant DNA,the plasmid rescue technique was used.pEL-7,one of plasmids from left border of T-DNA,which contained pBR322 was selected from ampicillin plate.The T-DNA fragment of pEL-7 was checked by restriction enzyme analysis and Southern Blot.Restriction analysis confirmed the presence of known sites of EcoRI,PstI and PvuII on it.For confirming the presence of flanking plant DNA in this plasmid,pEL-7 DNA was labeled and hybridized with wild type and mutant plant DNA.The Southern Blot indicated the hybridization band in both of them.Furthermore,the junction of T-DNA/plant DNA was subcloned into bluescript SK+ and sequenced by Applied Biosystem 373A sequencer.The results showed the 822 bp fragment contained a 274 bp sequence,which is 99.6%homolog(273bp/274bp) to Ti plasmid pTi 15955,DNA.The bp of left 25 bp border repeat were also found in the juction of T-DNA and Plant DNA. Taken together,pEL-7 should coutain a joint fragment of T-DNA and flanking plant DNA.This plasmid DNA could be used for the isolation of plant gene,which will be helpful to elucidate the relationship between gene function and plant embryo development.

  3. Dynamic light regulation of translation status in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Julia eBailey-Serres

    2012-04-01

    Full Text Available Light, a dynamic environmental parameter, is an essential regulator of plant growth and development. Light-regulated transcriptional networks are well documented, whereas light-regulated post-transcriptional regulation has received only limited attention. In this study, dynamics in translation of cytosolic mRNAs were evaluated at the genome-level in Arabidopsis thaliana seedlings grown under a typical light / dark diurnal regime, shifted to darkness at midday and then re-illuminated. One-hour of unanticipated darkness reduced levels of polyribosomes (polysomes by 17% in a manner consistent with inhibition of initiation of translation. This down-regulation of protein synthesis was reversed within 10 minutes of re-illumination. Quantitative comparison of the total cellular population of transcripts (the transcriptome to those associated with one or more 80S ribosome (the translatome identified over 1600 mRNAs that are differentially translated in response to light availability. Unanticipated darkness limited transcription and translation of mRNAs encoding components of the photosynthetic machinery. Many mRNAs encoding proteins associated with the energy demanding process of protein synthesis were stable but sequestered in the dark, in a rapidly reversible manner. A meta-analysis determined these same transcripts were similarly and coordinately regulated in response to changes in oxygen availability. The dark and hypoxia translationally repressed mRNAs lack highly supported candidate RNA-regulatory elements but are characterized by G+C-rich 5’-untranslated regions. We propose that dynamic regulation of the translational status of a subset of cellular mRNAs serves as a general energy conservation mechanism.

  4. Identification and structural analysis of a novel snoRNA gene cluster from Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A Z2 snoRNA gene cluster,consisting of four antisense snoRNA genes, was identified from Arabidopsis thaliana. The sequence and structural analysis showed that the Z2 snoRNA gene cluster might be transcribed as a polycistronic precursor from an upstream promoter, and the intergenic spacers of the gene cluster encode the 'hairpin' structures similar to the processing recognition signals of yeast Saccharomyces cerevisiae polycistronic snoRNA precursor. The results also revealed that plant snoRNA gene with multiple copies is a characteristic in common, and provides a good system for further revealing the transcription and expression mechanism of plant snoRNA gene cluster.

  5. Functional investigation of the plant-specific long coiled-coil proteins PAMP-INDUCED COILED-COIL (PICC and PICC-LIKE (PICL in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Sowmya Venkatakrishnan

    Full Text Available We have identified and characterized two Arabidopsis long coiled-coil proteins PAMP-INDUCED COILED-COIL (PICC and PICC-LIKE (PICL. PICC (147 kDa and PICL (87 kDa are paralogs that consist predominantly of a long coiled-coil domain (expanded in PICC, with a predicted transmembrane domain at the immediate C-terminus. Orthologs of PICC and PICL were found exclusively in vascular plants. PICC and PICL GFP fusion proteins are anchored to the cytoplasmic surface of the endoplasmic reticulum (ER membrane by a C-terminal transmembrane domain and a short tail domain, via a tail-anchoring mechanism. T-DNA-insertion mutants of PICC and PICL as well as the double mutant show an increased sensitivity to the plant abiotic stress hormone abscisic acid (ABA in a post-germination growth response. PICC, but not PICL gene expression is induced by the bacterial pathogen-associated molecular pattern (PAMP flg22. T-DNA insertion alleles of PICC, but not PICL, show increased susceptibility to the non-virulent strain P. syringae pv. tomato DC3000 hrcC, but not to the virulent strain P. syringae pv. tomato DC3000. This suggests that PICC mutants are compromised in PAMP-triggered immunity (PTI. The data presented here provide first evidence for the involvement of a plant long coiled-coil protein in a plant defense response.

  6. The rules of gene expression in plants: Organ identity and gene body methylation are key factors for regulation of gene expression in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Gutiérrez Rodrigo A

    2008-09-01

    Full Text Available Abstract Background Microarray technology is a widely used approach for monitoring genome-wide gene expression. For Arabidopsis, there are over 1,800 microarray hybridizations representing many different experimental conditions on Affymetrix™ ATH1 gene chips alone. This huge amount of data offers a unique opportunity to infer the principles that govern the regulation of gene expression in plants. Results We used bioinformatics methods to analyze publicly available data obtained using the ATH1 chip from Affymetrix. A total of 1887 ATH1 hybridizations were normalized and filtered to eliminate low-quality hybridizations. We classified and compared control and treatment hybridizations and determined differential gene expression. The largest differences in gene expression were observed when comparing samples obtained from different organs. On average, ten-fold more genes were differentially expressed between organs as compared to any other experimental variable. We defined "gene responsiveness" as the number of comparisons in which a gene changed its expression significantly. We defined genes with the highest and lowest responsiveness levels as hypervariable and housekeeping genes, respectively. Remarkably, housekeeping genes were best distinguished from hypervariable genes by differences in methylation status in their transcribed regions. Moreover, methylation in the transcribed region was inversely correlated (R2 = 0.8 with gene responsiveness on a genome-wide scale. We provide an example of this negative relationship using genes encoding TCA cycle enzymes, by contrasting their regulatory responsiveness to nitrate and methylation status in their transcribed regions. Conclusion Our results indicate that the Arabidopsis transcriptome is largely established during development and is comparatively stable when faced with external perturbations. We suggest a novel functional role for DNA methylation in the transcribed region as a key determinant

  7. Biochemical and structural properties of cyanases from Arabidopsis thaliana and Oryza sativa.

    Science.gov (United States)

    Qian, Dan; Jiang, Lin; Lu, Lu; Wei, Chunhong; Li, Yi

    2011-01-01

    Cyanate is toxic to all organisms. Cyanase converts cyanate to CO₂ and NH₃ in a bicarbonate-dependent reaction. The biophysical functions and biochemical characteristics of plant cyanases are poorly studied, although it has been investigated in a variety of proteobacteria, cyanobacteria and fungi. In this study, we characterised plant cyanases from Arabidopsis thaliana and Oryza sativa (AtCYN and OsCYN). Prokaryotic-expressed AtCYN and OsCYN both showed cyanase activity in vitro. Temperature had a similar influence on the activity of both cyanases, but pH had a differential impact on AtCYN and OsCYN activity. Homology modelling provided models of monomers of AtCYN and OsCYN, and a coimmunoprecipitation assay and gel filtration indicated that AtCYN and OsCYN formed homodecamers. The analysis of single-residue mutants of AtCYN indicated that the conserved catalytic residues also contributed to the stability of the homodecamer. KCNO treatment inhibited Arabidopsis germination and early seedling growth. Plants containing AtCYN or OsCYN exhibited resistance to KCNO stress, which demonstrated that one role of cyanases in plants is detoxification. Transcription level of AtCYN was higher in the flower than in other organs of Arabidopsis. AtCYN transcription was not significantly affected by KCNO treatment in Arabidopsis, but was induced by salt stress. This research broadens our knowledge on plant detoxification of cyanate via cyanase.

  8. Biochemical and structural properties of cyanases from Arabidopsis thaliana and Oryza sativa.

    Directory of Open Access Journals (Sweden)

    Dan Qian

    Full Text Available Cyanate is toxic to all organisms. Cyanase converts cyanate to CO₂ and NH₃ in a bicarbonate-dependent reaction. The biophysical functions and biochemical characteristics of plant cyanases are poorly studied, although it has been investigated in a variety of proteobacteria, cyanobacteria and fungi. In this study, we characterised plant cyanases from Arabidopsis thaliana and Oryza sativa (AtCYN and OsCYN. Prokaryotic-expressed AtCYN and OsCYN both showed cyanase activity in vitro. Temperature had a similar influence on the activity of both cyanases, but pH had a differential impact on AtCYN and OsCYN activity. Homology modelling provided models of monomers of AtCYN and OsCYN, and a coimmunoprecipitation assay and gel filtration indicated that AtCYN and OsCYN formed homodecamers. The analysis of single-residue mutants of AtCYN indicated that the conserved catalytic residues also contributed to the stability of the homodecamer. KCNO treatment inhibited Arabidopsis germination and early seedling growth. Plants containing AtCYN or OsCYN exhibited resistance to KCNO stress, which demonstrated that one role of cyanases in plants is detoxification. Transcription level of AtCYN was higher in the flower than in other organs of Arabidopsis. AtCYN transcription was not significantly affected by KCNO treatment in Arabidopsis, but was induced by salt stress. This research broadens our knowledge on plant detoxification of cyanate via cyanase.

  9. Circadian clock and PIF4-mediated external coincidence mechanism coordinately integrates both of the cues from seasonal changes in photoperiod and temperature to regulate plant growth in Arabidopsis thaliana.

    Science.gov (United States)

    Nomoto, Yuji; Kubozono, Saori; Miyachi, Miki; Yamashino, Takafumi; Nakamichi, Norihito; Mizuno, Takeshi

    2013-02-01

    In Arabidopsis thaliana, the circadian clock regulates the photoperiodic plant growth including the elongation of hypocotyls in a short-days (SDs)-specific manner. The clock-controlled PHYTOCHROME-INTERACTING FACTOR 4 (PIF4) gene encoding a basic helix-loop-helix (bHLH) transcription factor plays crucial roles in this regulation. The SDs-specific elongation of hypocotyls is best explained by accumulation of the active PIF4 proteins at the end of night specifically in SDs due to coincidence between internal (circadian clock) and external (photoperiod) cues. However, this external coincidence model was challenged with the recent finding that the elongation of hypocotyls is markedly promoted at high growth temperature (28˚C) even in long-days (LDs), implying that the model to explain the photoperiodic response of plant architecture appears to be conditional on ambient temperature. With regard to this problem, the results of this and previous studies showed that the model holds under a wide range of ambient temperature conditions (16˚C to 28˚C). We propose that the circadian clock and PIF4-mediated external coincidence mechanism coordinately integrates both of the cues from seasonal changes in photoperiod and temperature to regulate plant growth in natural habitats.

  10. Mutants in Arabidopsis thaliana with altered shoot gravitropism

    Energy Technology Data Exchange (ETDEWEB)

    Bullen, B.L.; Poff, K.L.

    1987-04-01

    A procedure has been developed and used to screen 40,000 m-2 seedlings of Arabidopsis thaliana for strains with altered shoot gravitropism. Several strains have been identified for which shoot gravitropism is considerably more random than that of their wild-type parent (based on frequency distribution histograms of the gravitropic response to a 1 g stimulus). One such strain exhibits normal hypocotyl phototropism and normal root gravitropism. Thus, the gravitropism pathway in the shoot contains at least one mutable element which is not required for root gravitropism.

  11. Identification of imprinted genes subject to parent-of-origin specific expression in Arabidopsis thaliana seeds

    LENUS (Irish Health Repository)

    McKeown, Peter C

    2011-08-12

    Abstract Background Epigenetic regulation of gene dosage by genomic imprinting of some autosomal genes facilitates normal reproductive development in both mammals and flowering plants. While many imprinted genes have been identified and intensively studied in mammals, smaller numbers have been characterized in flowering plants, mostly in Arabidopsis thaliana. Identification of additional imprinted loci in flowering plants by genome-wide screening for parent-of-origin specific uniparental expression in seed tissues will facilitate our understanding of the origins and functions of imprinted genes in flowering plants. Results cDNA-AFLP can detect allele-specific expression that is parent-of-origin dependent for expressed genes in which restriction site polymorphisms exist in the transcripts derived from each allele. Using a genome-wide cDNA-AFLP screen surveying allele-specific expression of 4500 transcript-derived fragments, we report the identification of 52 maternally expressed genes (MEGs) displaying parent-of-origin dependent expression patterns in Arabidopsis siliques containing F1 hybrid seeds (3, 4 and 5 days after pollination). We identified these MEGs by developing a bioinformatics tool (GenFrag) which can directly determine the identities of transcript-derived fragments from (i) their size and (ii) which selective nucleotides were added to the primers used to generate them. Hence, GenFrag facilitates increased throughput for genome-wide cDNA-AFLP fragment analyses. The 52 MEGs we identified were further filtered for high expression levels in the endosperm relative to the seed coat to identify the candidate genes most likely representing novel imprinted genes expressed in the endosperm of Arabidopsis thaliana. Expression in seed tissues of the three top-ranked candidate genes, ATCDC48, PDE120 and MS5-like, was confirmed by Laser-Capture Microdissection and qRT-PCR analysis. Maternal-specific expression of these genes in Arabidopsis thaliana F1 seeds was

  12. Photorespiratory bypasses lead to increased growth in Arabidopsis thaliana: Are predictions consistent with experimental evidence?

    Directory of Open Access Journals (Sweden)

    Georg eBasler

    2016-04-01

    Full Text Available Arguably the biggest challenge of modern plant systems biology lies in predicting the performance of plant species, and crops in particular, upon different intracellular and external perturbations. Recently, an increased growth of Arabidopsis thaliana plants was achieved by introducing two different photorespiratory bypasses via metabolic engineering. Here we investigate the extent to which these findings match the predictions from constraint-based modeling. To determine the effect of the employed metabolic network model on the predictions, we perform a comparative analysis involving three state-of-the-art metabolic reconstructions of Arabidopsis thaliana. In addition, we investigate three scenarios with respect to experimental findings on the ratios of the carboxylation and oxygenation reactions of RuBisCO. We demonstrate that the condition-dependent growth phenotypes of one of the engineered bypasses can be qualitatively reproduced by each reconstruction, particularly upon considering the additional constraints with respect to the ratio of fluxes for the RuBisCO reactions. Moreover, our results lend support for the hypothesis of a reduced photorespiration in the engineered plants, and indicate that specific changes in CO2 exchange as well as in the proxies for cofactor turnover are associated with the predicted growth increase in the engineered plants. We discuss our findings with respect to the structure of the used models, the modeling approaches taken, and the available experimental evidence. Our study sets the ground for investigating other strategies for increase of plant biomass by insertion of synthetic reactions.

  13. Genetic analysis of photoreceptor action pathways in Arabidopsis thaliana

    Energy Technology Data Exchange (ETDEWEB)

    1991-01-01

    The specific strategies and long-term goals of this proposal remain intact relative to the original proposal. We continue to isolate and characterize photomorphogenic mutants of Arabidopsis thaliana. The molecular and biochemical characterization of one of these mutants, det1, has led to one publication of original data and to one Society for Experimental Biology Symposium paper (see below). The phenotype of a second mutant, det2, has also been studied during this funding period. In addition, we have continued work on a general strategy to isolate mutations in trans-acting regulatory factors that mediate light-regulated gene expression, and have identified several potentially interesting regulatory mutants. In the third funding period, we will concentrate on the genetical, biochemical, and molecular characterization of these new mutants. Construction of double mutants between the new mutants and the previously characterized morphological mutants should allow us to construct a pathway for light-regulated seedling development in Arabidopsis.

  14. In silico comparison of transcript abundances during Arabidopsis thaliana and Glycine max resistance to Fusarium virguliforme

    Directory of Open Access Journals (Sweden)

    Iqbal M Javed

    2008-09-01

    Full Text Available Abstract Background Sudden death syndrome (SDS of soybean (Glycine max L. Merr. is an economically important disease, caused by the semi-biotrophic fungus Fusarium solani f. sp. glycines, recently renamed Fusarium virguliforme (Fv. Due to the complexity and length of the soybean-Fusarium interaction, the molecular mechanisms underlying plant resistance and susceptibility to the pathogen are not fully understood. F. virguliforme has a very wide host range for the ability to cause root rot and a very narrow host range for the ability to cause a leaf scorch. Arabidopsis thaliana is a host for many types of phytopathogens including bacteria, fungi, viruses and nematodes. Deciphering the variations among transcript abundances (TAs of functional orthologous genes of soybean and A. thaliana involved in the interaction will provide insights into plant resistance to F. viguliforme. Results In this study, we reported the analyses of microarrays measuring TA in whole plants after A. thaliana cv 'Columbia' was challenged with fungal pathogen F. virguliforme. Infection caused significant variations in TAs. The total number of increased transcripts was nearly four times more than that of decreased transcripts in abundance. A putative resistance pathway involved in responding to the pathogen infection in A. thaliana was identified and compared to that reported in soybean. Conclusion Microarray experiments allow the interrogation of tens of thousands of transcripts simultaneously and thus, the identification of plant pathways is likely to be involved in plant resistance to Fusarial pathogens. Dissection of the set functional orthologous genes between soybean and A. thaliana enabled a broad view of the functional relationships and molecular interactions among plant genes involved in F. virguliforme resistance.

  15. The F-box protein MAX2 contributes to resistance to bacterial phytopathogens in Arabidopsis thaliana.

    Science.gov (United States)

    Piisilä, Maria; Keceli, Mehmet A; Brader, Günter; Jakobson, Liina; Jõesaar, Indrek; Sipari, Nina; Kollist, Hannes; Palva, E Tapio; Kariola, Tarja

    2015-02-13

    The Arabidopsis thaliana F-box protein MORE AXILLARY GROWTH2 (MAX2) has previously been characterized for its role in plant development. MAX2 appears essential for the perception of the newly characterized phytohormone strigolactone, a negative regulator of polar auxin transport in Arabidopsis. A reverse genetic screen for F-box protein mutants altered in their stress responses identified MAX2 as a component of plant defense. Here we show that MAX2 contributes to plant resistance against pathogenic bacteria. Interestingly, max2 mutant plants showed increased susceptibility to the bacterial necrotroph Pectobacterium carotovorum as well as to the hemi-biotroph Pseudomonas syringae but not to the fungal necrotroph Botrytis cinerea. max2 mutant phenotype was associated with constitutively increased stomatal conductance and decreased tolerance to apoplastic ROS but also with alterations in hormonal balance. Our results suggest that MAX2 previously characterized for its role in regulation of polar auxin transport in Arabidopsis, and thus plant development also significantly influences plant disease resistance. We conclude that the increased susceptibility to P. syringae and P. carotovorum is due to increased stomatal conductance in max2 mutants promoting pathogen entry into the plant apoplast. Additional factors contributing to pathogen susceptibility in max2 plants include decreased tolerance to pathogen-triggered apoplastic ROS and alterations in hormonal signaling.

  16. Hydrogen Sulfide Regulates Ethylene-induced Stomatal Closure in Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    Zhihui Hou; Lanxiang Wang; Jing Liu; Lixia Hou; Xin Liu

    2013-01-01

    Hydrogen sulfide (H2S) is a newly-discovered signaling molecule in plants and has caused increasing attention in recent years,but its function in stomatal movement is unclear.In plants,H2S is synthesized via cysteine degradation catalyzed by D-/L-cysteine desulfhydrase (D-/L-CDes).AtD-/L-CDes::GUS transgenic Arabidopsis thaliana (L.) Heynh.plants were generated and used to investigate gene expression patterns,and results showed that AtD-/L-CDes can be expressed in guard cells.We also determined the subcellular localization of AtD-/L-CDes using transgenic plants of AtD-/L-CDes::GFP,and the results showed that AtD-CDes and AtL-CDes are located in the chloroplast and in the cytoplasm,respectively.The transcript levels of AtD-CDes and AtL-CDes were affected by the chemicals that cause stomatal closure.Among these factors,ACC,a precursor of ethylene,has the most significant effect,which indicates that the H2S generated from D-/L-CDes may play an important role in ethylene-induced stomatal closure.Meanwhile,H2S synthetic inhibitors significantly inhibited ethylene-induced stomatal closure in Arabidopsis.Ethylene treatment caused an increase of H2S production and of AtD-/L-CDes activity in Arabidopsis leaves.AtD-/L-CDes over-expressing plants exhibited enhanced induction of stomatal closure compared to the wild-type after ethylene treatment; however,the effect was not observed in the Atd-cdes and Atl-cdes mutants.In conclusion,our results suggest that the D-/L-CDes-generated H2S is involved in the regulation of ethylene-induced stomatal closure in Arabidopsis thaliana.

  17. Physiological and Molecular Features of the Pathosystem Arabidopsis thaliana L.-Sclerotinia sclerotiorum Libert

    Institute of Scientific and Technical Information of China (English)

    Fu-Ming Dai; Tong Xu; Gerhard A. Wolf; Zu-Hua He

    2006-01-01

    The fungal pathogen Sclerotinia sclerotiorum Libert causes rot diseases on many crops worldwide and large economic losses occur frequently because of a lack of resistant varieties. The pathogenesis of S. sclerotiorum and the molecular basis of plant responses to the pathogen are poorly understood. In the present investigation,the process of S. sclerotiorum infection in Arabidopsis thaliana L., a plant that is highly susceptible to this fungus, was analysed. In addition, the defense activation in the host was investigated. A convenient inoculation method using millet grain was developed for S. sclerotiorum in Arabidopsis. The fungus rapidly infected the plants, probably through ball- or cushion-like infection structures. Visible symptoms developed within 24h and plants were killed 72 h after inoculation. Cellulase, the main enzyme that caused host tissues to rot,was secreted by S. sclerotiorum in a pH-dependent manner. Oxalic acid, another pathogenic factor secreted by the fungus, induced necrotic lesions on the leaves. Infection with S. sclerotiorum strongly induced the production of the pathogenesis-related (PR) proteins β-1,3-glucanase and chitinase in Arabidopsis.Furthermore, the PR gene PDF. 1 was induced, but not PR1, indicating that the pathogen activated basal defense of jasmonic acid/ethylene dependence, which is consistent with its necrotrophic characteristics.This pathosystem for Arabidopsis-S. sclerotiorum could provide an approach for the analysis of the interactions between S. sclerotiorum and other crops, thereby facilitating genetic manipulation techniques for controlling this pathogen.

  18. Comparative Transcriptomics of Arabidopsis thaliana Sperm Cells

    Science.gov (United States)

    In flowering plants the two sperm cells are embedded within the cytoplasm of the growing pollen tube and as such are passively transported to the embryo sac, wherein double fertilization occurs upon their release. Understanding the mechanisms and conditions by which male gametes mature and take part...

  19. Fructose and glucose signaling in Arabidopsis thaliana

    NARCIS (Netherlands)

    Wind, J.J.|info:eu-repo/dai/nl/268444412

    2012-01-01

    All life on earth depends on photosynthesis, a process by which energy from sunlight is used to convert water and carbon dioxide into sugars and oxygen. In plants, sugars are used as building blocks for growth, energy and transport. Sugars have an important role as signaling molecule as well, and

  20. Spatio-temporal expression patterns of Arabidopsis thaliana and Medicago truncatula defensin-like genes.

    Directory of Open Access Journals (Sweden)

    Mesfin Tesfaye

    Full Text Available Plant genomes contain several hundred defensin-like (DEFL genes that encode short cysteine-rich proteins resembling defensins, which are well known antimicrobial polypeptides. Little is known about the expression patterns or functions of many DEFLs because most were discovered recently and hence are not well represented on standard microarrays. We designed a custom Affymetrix chip consisting of probe sets for 317 and 684 DEFLs from Arabidopsis thaliana and Medicago truncatula, respectively for cataloging DEFL expression in a variety of plant organs at different developmental stages and during symbiotic and pathogenic associations. The microarray analysis provided evidence for the transcription of 71% and 90% of the DEFLs identified in Arabidopsis and Medicago, respectively, including many of the recently annotated DEFL genes that previously lacked expression information. Both model plants contain a subset of DEFLs specifically expressed in seeds or fruits. A few DEFLs, including some plant defensins, were significantly up-regulated in Arabidopsis leaves inoculated with Alternaria brassicicola or Pseudomonas syringae pathogens. Among these, some were dependent on jasmonic acid signaling or were associated with specific types of immune responses. There were notable differences in DEFL gene expression patterns between Arabidopsis and Medicago, as the majority of Arabidopsis DEFLs were expressed in inflorescences, while only a few exhibited root-enhanced expression. By contrast, Medicago DEFLs were most prominently expressed in nitrogen-fixing root nodules. Thus, our data document salient differences in DEFL temporal and spatial expression between Arabidopsis and Medicago, suggesting distinct signaling routes and distinct roles for these proteins in the two plant species.

  1. Spatio-temporal expression patterns of Arabidopsis thaliana and Medicago truncatula defensin-like genes.

    Science.gov (United States)

    Tesfaye, Mesfin; Silverstein, Kevin At; Nallu, Sumitha; Wang, Lin; Botanga, Christopher J; Gomez, S Karen; Costa, Liliana M; Harrison, Maria J; Samac, Deborah A; Glazebrook, Jane; Katagiri, Fumiaki; Gutierrez-Marcos, Jose F; Vandenbosch, Kathryn A

    2013-01-01

    Plant genomes contain several hundred defensin-like (DEFL) genes that encode short cysteine-rich proteins resembling defensins, which are well known antimicrobial polypeptides. Little is known about the expression patterns or functions of many DEFLs because most were discovered recently and hence are not well represented on standard microarrays. We designed a custom Affymetrix chip consisting of probe sets for 317 and 684 DEFLs from Arabidopsis thaliana and Medicago truncatula, respectively for cataloging DEFL expression in a variety of plant organs at different developmental stages and during symbiotic and pathogenic associations. The microarray analysis provided evidence for the transcription of 71% and 90% of the DEFLs identified in Arabidopsis and Medicago, respectively, including many of the recently annotated DEFL genes that previously lacked expression information. Both model plants contain a subset of DEFLs specifically expressed in seeds or fruits. A few DEFLs, including some plant defensins, were significantly up-regulated in Arabidopsis leaves inoculated with Alternaria brassicicola or Pseudomonas syringae pathogens. Among these, some were dependent on jasmonic acid signaling or were associated with specific types of immune responses. There were notable differences in DEFL gene expression patterns between Arabidopsis and Medicago, as the majority of Arabidopsis DEFLs were expressed in inflorescences, while only a few exhibited root-enhanced expression. By contrast, Medicago DEFLs were most prominently expressed in nitrogen-fixing root nodules. Thus, our data document salient differences in DEFL temporal and spatial expression between Arabidopsis and Medicago, suggesting distinct signaling routes and distinct roles for these proteins in the two plant species.

  2. Defence responses of arabidopsis thaliana to infection by pseudomonas syringae are regulated by the circadian clock

    KAUST Repository

    Bhardwaj, Vaibhav

    2011-10-31

    The circadian clock allows plants to anticipate predictable daily changes in abiotic stimuli, such as light; however, whether the clock similarly allows plants to anticipate interactions with other organisms is unknown. Here we show that Arabidopsis thaliana (Arabidopsis) has circadian clock-mediated variation in resistance to the virulent bacterial pathogen Pseudomonas syringae pv. tomato DC3000 (Pst DC3000), with plants being least susceptible to infection in the subjective morning. We suggest that the increased resistance to Pst DC3000 observed in the morning in Col-0 plants results from clock-mediated modulation of pathogen associated molecular pattern (PAMP)-triggered immunity. Analysis of publicly available microarray data revealed that a large number of Arabidopsis defence-related genes showed both diurnal- and circadian-regulation, including genes involved in the perception of the PAMP flagellin which exhibit a peak in expression in the morning. Accordingly, we observed that PAMP-triggered callose deposition was significantly higher in wild-type plants inoculated with Pst DC3000 hrpA in the subjective morning than in the evening, while no such temporal difference was evident in arrhythmic plants. Our results suggest that PAMP-triggered immune responses are modulated by the circadian clock and that temporal regulation allows plants to anticipate and respond more effectively to pathogen challenges in the daytime. © 2011 Bhardwaj et al.

  3. The phenotype of Arabidopsis thaliana det1 mutants suggest a role for cytokinins in greening

    Energy Technology Data Exchange (ETDEWEB)

    Chory, J.; Aguilar, N.; Peto, C.A.

    1990-01-01

    When grown in the absence of light, the det1 mutants of Arabidopsis thaliana develop characteristics of light-grown plants by morphological, cellular, and molecular criteria. Further, in light-grown plants, mutations in the DET1 gene affect cell-type-specific expression of light-regulated genes and the chloroplast developmental program. Here we show that the addition of exogenously added cytokinins (either 2-isopentenyl adenine, kinetin, or benzyladenine) to the growth medium of dark-germinated wild-type seedlings results in seedlings that resemble det1 mutants, instead of having the normal etiolated morphology. Like det1 mutants, these dark-grown seedlings now contain chloroplasts and have high levels of expression of genes that are normally light''-regulated. These results suggest an important role for cytokinins during greening of Arabidopsis, and may implicate cytokinin levels or an increased sensitivity to cytokinins as explanations for some of the observed phenotypes of det1 mutants.

  4. Comparative proteomics and metallomics studies in Arabidopsis thaliana leaf tissues: evaluation of the selenium addition in transgenic and nontransgenic plants using two-dimensional difference gel electrophoresis and laser ablation imaging.

    Science.gov (United States)

    Maciel, Bruna C M; Barbosa, Herbert S; Pessôa, Gustavo S; Salazar, Marcela M; Pereira, Gonçalo A G; Gonçalves, Danieli C; Ramos, Carlos H I; Arruda, Marco A Z

    2014-04-01

    The main goal of this work is to evaluate some differential protein species in transgenic (T) and nontransgenic (NT) Arabidopsis thaliana plants after their cultivation in the presence or absence of sodium selenite. The transgenic line was obtained through insertion of CaMV 35S controlling nptII gene. Comparative proteomics through 2D-DIGE is carried out in four different groups (NT × T; NT × Se-NT (where Se is selenium); Se-NT × Se-T, and T × Se-T). Although no differential proteins are achieved in the T × Se-T group, for the others, 68 differential proteins (by applying a regulation factor ≥1.5) are achieved, and 27 of them accurately characterized by ESI-MS/MS. These proteins are classified into metabolism, energy, signal transduction, disease/defense categories, and some of them are involved in the glycolysis pathway-Photosystems I and II and ROS combat. Additionally, laser ablation imaging is used for evaluating the Se and sulfur distribution in leaves of different groups, corroborating some results obtained and related to proteins involved in the glycolysis pathway. From these results, it is possible to conclude that the genetic modification also confers to the plant resistance to oxidative stress.

  5. Phosphate sensing and signalling in Arabidopsis thaliana

    OpenAIRE

    2013-01-01

    Phosphate (Pi) deficiency is a global problem for food production. Plants have evolved complex mechanisms to adapt to low Pi. We focused on the initial aspects of adaptation to low Pi - perception and immediate-early responses to changes in external Pi. To examine whether a labile repressor controls expression of the high affinity Pi transporter, Pht1;1, we performed electrophoretic mobility shift assays (EMSA) but observed only weak protein-DNA binding activity using extrac...

  6. Free-flow electrophoresis for fractionation of Arabidopsis thaliana membranes.

    Science.gov (United States)

    Bardy, N; Carrasco, A; Galaud, J P; Pont-Lezica, R; Canut, H

    1998-06-01

    Highly purified tonoplast and plasma membrane vesicles were isolated from microsomes of Arabidopsis thaliana by preparative free-flow electrophoresis. The most electronegative fractions were identified as tonoplast using nitrate-inhibited Mg2+-ATPase as enzyme marker. The least electronegative fractions were identified as plasma membrane using glucan-synthase II, UDPG: sterol-glucosyl-transferase, and vanadate-inhibited Mg2+-ATPase as enzyme markers. Other membrane markers, latent inosine-5'-diphosphatase (Golgi), NADPH-cytochrome-c reductase (endoplasmic reticulum) and cytochrome-c oxidase (mitochondria) were recovered in the fractions intermediate between tonoplast and plasma membrane. Immunoblot analysis of membrane fractions by antibodies directed against tonoplast and plasma membrane proteins confirmed the nature and the purity of the isolated membranes. The cytoskeletal protein actin, which was also identified by immunoblotting, was found to be specifically attached to the plasma membrane vesicles. The structural and functional integrity of the isolated membranes from Arabidopsis thaliana is discussed in the light of results obtained for the location of receptors and enzymes, or for the determination of ligand binding activity.

  7. EDS1 contributes to nonhost resistance of Arabidopsis thaliana against Erwinia amylovora.

    Science.gov (United States)

    Moreau, Manon; Degrave, Alexandre; Vedel, Régine; Bitton, Frédérique; Patrit, Oriane; Renou, Jean-Pierre; Barny, Marie-Anne; Fagard, Mathilde

    2012-03-01

    Erwinia amylovora causes fire blight in rosaceous plants. In nonhost Arabidopsis thaliana, E. amylovora triggers necrotic symptoms associated with transient bacterial multiplication, suggesting either that A. thaliana lacks a susceptibility factor or that it actively restricts E. amylovora growth. Inhibiting plant protein synthesis at the time of infection led to an increase in necrosis and bacterial multiplication and reduced callose deposition, indicating that A. thaliana requires active protein synthesis to restrict E. amylovora growth. Analysis of the callose synthase-deficient pmr4-1 mutant indicated that lack of callose deposition alone did not lead to increased sensitivity to E. amylovora. Transcriptome analysis revealed that approximately 20% of the genes induced following E. amylovora infection are related to defense and signaling. Analysis of mutants affected in NDR1 and EDS1, two main components of the defense-gene activation observed, revealed that E. amylovora multiplied ten times more in the eds1-2 mutant than in the wild type but not in the ndr1-1 mutant. Analysis of mutants affected in three WRKY transcription factors showing EDS1-dependent activation identified WRKY46 and WRKY54 as positive regulators and WRKY70 as a negative regulator of defense against E. amylovora. Altogether, we show that EDS1 is a positive regulator of nonhost resistance against E. amylovora in A. thaliana and hypothesize that it controls the production of several effective defenses against E. amylovora through the action of WRKY46 and WRKY54, while WRKY70 acts as a negative regulator.

  8. Allyl Isothiocyanate Inhibits Actin-Dependent Intracellular Transport in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Bjørnar Sporsheim

    2015-12-01

    Full Text Available Volatile allyl isothiocyanate (AITC derives from the biodegradation of the glucosinolate sinigrin and has been associated with growth inhibition in several plants, including the model plant Arabidopsis thaliana. However, the underlying cellular mechanisms of this feature remain scarcely investigated in plants. In this study, we present evidence of an AITC-induced inhibition of actin-dependent intracellular transport in A. thaliana. A transgenic line of A. thaliana expressing yellow fluorescent protein (YFP-tagged actin filaments was used to show attenuation of actin filament movement by AITC. This appeared gradually in a time- and dose-dependent manner and resulted in actin filaments appearing close to static. Further, we employed four transgenic lines with YFP-fusion proteins labeling the Golgi apparatus, endoplasmic reticulum (ER, vacuoles and peroxisomes to demonstrate an AITC-induced inhibition of actin-dependent intracellular transport of or, in these structures, consistent with the decline in actin filament movement. Furthermore, the morphologies of actin filaments, ER and vacuoles appeared aberrant following AITC-exposure. However, AITC-treated seedlings of all transgenic lines tested displayed morphologies and intracellular movements similar to that of the corresponding untreated and control-treated plants, following overnight incubation in an AITC-absent environment, indicating that AITC-induced decline in actin-related movements is a reversible process. These findings provide novel insights into the cellular events in plant cells following exposure to AITC, which may further expose clues to the physiological significance of the glucosinolate-myrosinase system.

  9. A high throughput genetic screen identifies new early meiotic recombination functions in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Arnaud De Muyt

    2009-09-01

    Full Text Available Meiotic recombination is initiated by the formation of numerous DNA double-strand breaks (DSBs catalysed by the widely conserved Spo11 protein. In Saccharomyces cerevisiae, Spo11 requires nine other proteins for meiotic DSB formation; however, unlike Spo11, few of these are conserved across kingdoms. In order to investigate this recombination step in higher eukaryotes, we took advantage of a high-throughput meiotic mutant screen carried out in the model plant Arabidopsis thaliana. A collection of 55,000 mutant lines was screened, and spo11-like mutations, characterised by a drastic decrease in chiasma formation at metaphase I associated with an absence of synapsis at prophase, were selected. This screen led to the identification of two populations of mutants classified according to their recombination defects: mutants that repair meiotic DSBs using the sister chromatid such as Atdmc1 or mutants that are unable to make DSBs like Atspo11-1. We found that in Arabidopsis thaliana at least four proteins are necessary for driving meiotic DSB repair via the homologous chromosomes. These include the previously characterised DMC1 and the Hop1-related ASY1 proteins, but also the meiotic specific cyclin SDS as well as the Hop2 Arabidopsis homologue AHP2. Analysing the mutants defective in DSB formation, we identified the previously characterised AtSPO11-1, AtSPO11-2, and AtPRD1 as well as two new genes, AtPRD2 and AtPRD3. Our data thus increase the number of proteins necessary for DSB formation in Arabidopsis thaliana to five. Unlike SPO11 and (to a minor extent PRD1, these two new proteins are poorly conserved among species, suggesting that the DSB formation mechanism, but not its regulation, is conserved among eukaryotes.

  10. Identification of QTLs affecting scopolin and scopoletin biosynthesis in Arabidopsis thaliana.

    Science.gov (United States)

    Siwinska, Joanna; Kadzinski, Leszek; Banasiuk, Rafal; Gwizdek-Wisniewska, Anna; Olry, Alexandre; Banecki, Bogdan; Lojkowska, Ewa; Ihnatowicz, Anna

    2014-10-18

    Scopoletin and its glucoside scopolin are important secondary metabolites synthesized in plants as a defense mechanism against various environmental stresses. They belong to coumarins, a class of phytochemicals with significant biological activities that is widely used in medical application and cosmetics industry. Although numerous studies showed that a variety of coumarins occurs naturally in several plant species, the details of coumarins biosynthesis and its regulation is not well understood. It was shown previously that coumarins (predominantly scopolin and scopoletin) occur in Arabidopsis thaliana (Arabidopsis) roots, but until now nothing is known about natural variation of their accumulation in this model plant. Therefore, the genetic architecture of coumarins biosynthesis in Arabidopsis has not been studied before. Here, the variation in scopolin and scopoletin content was assessed by comparing seven Arabidopsis accessions. Subsequently, a quantitative trait locus (QTL) mapping was performed with an Advanced Intercross Recombinant Inbred Lines (AI-RILs) mapping population EstC (Est-1 × Col). In order to reveal the genetic basis of both scopolin and scopoletin biosynthesis, two sets of methanol extracts were made from Arabidopsis roots and one set was additionally subjected to enzymatic hydrolysis prior to quantification done by high-performance liquid chromatography (HPLC). We identified one QTL for scopolin and five QTLs for scopoletin accumulation. The identified QTLs explained 13.86% and 37.60% of the observed phenotypic variation in scopolin and scopoletin content, respectively. In silico analysis of genes located in the associated QTL intervals identified a number of possible candidate genes involved in coumarins biosynthesis. Together, our results demonstrate for the first time that Arabidopsis is an excellent model for studying the genetic and molecular basis of natural variation in coumarins biosynthesis in plants. It additionally provides a basis

  11. Gene Mining for Proline Based Signaling Proteins in Cell Wall of Arabidopsis thaliana

    Science.gov (United States)

    Ihsan, Muhammad Z.; Ahmad, Samina J. N.; Shah, Zahid Hussain; Rehman, Hafiz M.; Aslam, Zubair; Ahuja, Ishita; Bones, Atle M.; Ahmad, Jam N.

    2017-01-01

    The cell wall (CW) as a first line of defense against biotic and abiotic stresses is of primary importance in plant biology. The proteins associated with cell walls play a significant role in determining a plant's sustainability to adverse environmental conditions. In this work, the genes encoding cell wall proteins (CWPs) in Arabidopsis were identified and functionally classified using geneMANIA and GENEVESTIGATOR with published microarrays data. This yielded 1605 genes, out of which 58 genes encoded proline-rich proteins (PRPs) and glycine-rich proteins (GRPs). Here, we have focused on the cellular compartmentalization, biological processes, and molecular functioning of proline-rich CWPs along with their expression at different plant developmental stages. The mined genes were categorized into five classes on the basis of the type of PRPs encoded in the cell wall of Arabidopsis thaliana. We review the domain structure and function of each class of protein, many with respect to the developmental stages of the plant. We have then used networks, hierarchical clustering and correlations to analyze co-expression, co-localization, genetic, and physical interactions and shared protein domains of these PRPs. This has given us further insight into these functionally important CWPs and identified a number of potentially new cell-wall related proteins in A. thaliana. PMID:28289422

  12. Nitrile-specifier Proteins Involved in Glucosinolate Hydrolysis in Arabidopsis thaliana*S⃞

    Science.gov (United States)

    Kissen, Ralph; Bones, Atle M.

    2009-01-01

    Glucosinolates are plant secondary metabolites present in Brassicaceae plants such as the model plant Arabidopsis thaliana. Intact glucosinolates are believed to be biologically inactive, whereas degradation products after hydrolysis have multiple roles in growth regulation and defense. The degradation of glucosinolates is catalyzed by thioglucosidases called myrosinases and leads by default to the formation of isothiocyanates. The interaction of a protein called epithiospecifier protein (ESP) with myrosinase diverts the reaction toward the production of epithionitriles or nitriles depending on the glucosinolate structure. Here we report the identification of a new group of nitrile-specifier proteins (AtNSPs) in A. thaliana able to generate nitriles in conjunction with myrosinase and a more detailed characterization of one member (AtNSP2). Recombinant AtNSP2 expressed in Escherichia coli was used to test its impact on the outcome of glucosinolate hydrolysis using a gas chromatography-mass spectrometry approach. AtNSP proteins share 30–45% sequence homology with A. thaliana ESP. Although AtESP and AtNSP proteins can switch myrosinase-catalyzed degradation of 2-propenylglucosinolate from isothiocyanate to nitrile, only AtESP generates the corresponding epithionitrile. Using the aromatic benzylglucosinolate, recombinant AtNSP2 is also able to direct product formation to the nitrile. Analysis of glucosinolate hydrolysis profiles of transgenic A. thaliana plants overexpressing AtNSP2 confirms its nitrile-specifier activity in planta. In silico expression analysis reveals distinctive expression patterns of AtNSPs, which supports a biological role for these proteins. In conclusion, we show that AtNSPs belonging to a new family of A. thaliana proteins structurally related to AtESP divert product formation from myrosinase-catalyzed glucosinolate hydrolysis and, thereby, likely affect the biological consequences of glucosinolate degradation. We discuss similarities and

  13. Erwinia amylovora type three-secreted proteins trigger cell death and defense responses in Arabidopsis thaliana.

    Science.gov (United States)

    Degrave, A; Fagard, M; Perino, C; Brisset, M N; Gaubert, S; Laroche, S; Patrit, O; Barny, M-A

    2008-08-01

    Erwinia amylovora is the bacterium responsible for fire blight, a necrotic disease affecting plants of the rosaceous family. E. amylovora pathogenicity requires a functional type three secretion system (T3SS). We show here that E. amylovora triggers a T3SS-dependent cell death on Arabidopsis thaliana. The plants respond by inducing T3SS-dependent defense responses, including salicylic acid (SA)-independent callose deposition, activation of the SA defense pathway, reactive oxygen species (ROS) accumulation, and part of the jasmonic acid/ethylene defense pathway. Several of these reactions are similar to what is observed in host plants. We show that the cell death triggered by E. amylovora on A. thaliana could not be simply explained by the recognition of AvrRpt2 ea by the resistance gene product RPS2. We then analyzed the role of type three-secreted proteins (T3SPs) DspA/E, HrpN, and HrpW in the induction of cell death and defense reactions in A. thaliana following infection with the corresponding E. amylovora mutant strains. HrpN and DspA/E were found to play an important role in the induction of cell death, activation of defense pathways, and ROS accumulation. None of the T3SPs tested played a major role in the induction of SA-independent callose deposition. The relative importance of T3SPs in A. thaliana is correlated with their relative importance in the disease process on host plants, indicating that A. thaliana can be used as a model to study their role.

  14. Proteomic analysis of S-nitrosylated proteins in Arabidopsis thaliana undergoing hypersensitive response

    DEFF Research Database (Denmark)

    Romero-Puertas, Maria C; Campostrini, Natascia; Mattè, Alessandro

    2008-01-01

    metabolism, signaling and antioxidant defense. The study of the effects of S-nitrosylation on the activity of the identified proteins and its role during the execution of the disease resistance response will help to understand S-nitrosylation function and significance in plants....... is the identification of the proteins that are subjected to this PTM. By using a proteomic approach involving 2-DE and MS we characterized, for the first time, changes in S-nitrosylated proteins in Arabidopsis thaliana undergoing HR. The 16 S-nitrosylated proteins identified are mostly enzymes serving intermediary...

  15. ATAF1 transcription factor directly regulates abscisic acid biosynthetic gene NCED3 in Arabidopsis thaliana

    DEFF Research Database (Denmark)

    Jensen, Michael Krogh; Lindemose, Søren; De Masi, Federico

    2013-01-01

    ATAF1, an Arabidopsis thaliana NAC transcription factor, plays important roles in plant adaptation to environmental stress and development. To search for ATAF1 target genes, we used protein binding microarrays and chromatin-immunoprecipitation (ChIP). This identified T[A,C,G]CGT[A,G] and TT[A,C,G...... abscisic acid (ABA) phytohormone biosynthetic gene NCED3. ChIP-qPCR and expression analysis showed that ATAF1 binding to the NCED3 promoter correlated with increased NCED3 expression and ABA hormone levels. These results indicate that ATAF1 regulates ABA biosynthesis....

  16. AtPIN: Arabidopsis thaliana Protein Interaction Network

    Directory of Open Access Journals (Sweden)

    Silva-Filho Marcio C

    2009-12-01

    Full Text Available Abstract Background Protein-protein interactions (PPIs constitute one of the most crucial conditions to sustain life in living organisms. To study PPI in Arabidopsis thaliana we have developed AtPIN, a database and web interface for searching and building interaction networks based on publicly available protein-protein interaction datasets. Description All interactions were divided into experimentally demonstrated or predicted. The PPIs in the AtPIN database present a cellular compartment classification (C3 which divides the PPI into 4 classes according to its interaction evidence and subcellular localization. It has been shown in the literature that a pair of genuine interacting proteins are generally expected to have a common cellular role and proteins that have common interaction partners have a high chance of sharing a common function. In AtPIN, due to its integrative profile, the reliability index for a reported PPI can be postulated in terms of the proportion of interaction partners that two proteins have in common. For this, we implement the Functional Similarity Weight (FSW calculation for all first level interactions present in AtPIN database. In order to identify target proteins of cytosolic glutamyl-tRNA synthetase (Cyt-gluRS (AT5G26710 we combined two approaches, AtPIN search and yeast two-hybrid screening. Interestingly, the proteins glutamine synthetase (AT5G35630, a disease resistance protein (AT3G50950 and a zinc finger protein (AT5G24930, which has been predicted as target proteins for Cyt-gluRS by AtPIN, were also detected in the experimental screening. Conclusions AtPIN is a friendly and easy-to-use tool that aggregates information on Arabidopsis thaliana PPIs, ontology, and sub-cellular localization, and might be a useful and reliable strategy to map protein-protein interactions in Arabidopsis. AtPIN can be accessed at http://bioinfo.esalq.usp.br/atpin.

  17. Two thymidine kinases and one multisubstrate deoxyribonucleoside kinase salvage DNA precursors in Arabidopsis thaliana

    DEFF Research Database (Denmark)

    Anders Ranegaard Clausen, Anders Ranegaard; Girandon, Lenart; Ali, Ashfaq

    2012-01-01

    Deoxyribonucleotides are the building blocks of DNA and can be synthesized via de novo and salvage pathways. Deoxyribonucleoside kinases (EC 2.7.1.145) salvage deoxyribonucleosides by transfer of a phosphate group to the 5' of a deoxyribonucleoside. This salvage pathway is well characterized...... in mammals, but in contrast, little is known about how plants salvage deoxyribonucleosides. We show that during salvage, deoxyribonucleosides can be phosphorylated by extracts of Arabidopsis thaliana into corresponding monophosphate compounds with an unexpected preference for purines over pyrimidines....... Deoxyribonucleoside kinase activities were present in all tissues during all growth stages. In the A. thaliana genome, we identified two types of genes that could encode enzymes which are involved in the salvage of deoxyribonucleosides. Thymidine kinase activity was encoded by two thymidine kinase 1 (EC 2...

  18. Two thymidine kinases and one multisubstrate deoxyribonucleoside kinase salvage DNA precursors in Arabidopsis thaliana

    DEFF Research Database (Denmark)

    Clausen, Anders R.; Girandon, Lenart; Ali, Ashfaq

    2012-01-01

    Deoxyribonucleotides are the building blocks of DNA and can be synthesized via de novo and salvage pathways. Deoxyribonucleoside kinases (EC 2.7.1.145) salvage deoxyribonucleosides by transfer of a phosphate group to the 5′ of a deoxyribonucleoside. This salvage pathway is well characterized...... in mammals, but in contrast, little is known about how plants salvage deoxyribonucleosides. We show that during salvage, deoxyribonucleosides can be phosphorylated by extracts of Arabidopsis thaliana into corresponding monophosphate compounds with an unexpected preference for purines over pyrimidines....... Deoxyribonucleoside kinase activities were present in all tissues during all growth stages. In the A. thaliana genome, we identified two types of genes that could encode enzymes which are involved in the salvage of deoxyribonucleosides. Thymidine kinase activity was encoded by two thymidine kinase 1 (EC 2...

  19. Two novel herbicide candidates affect Arabidopsis thaliana growth by inhibiting nitrogen and phosphate absorption.

    Science.gov (United States)

    Sun, Chongchong; Jin, Yujian; He, Haifeng; Wang, Wei; He, Hongwu; Fu, Zhengwei; Qian, Haifeng

    2015-09-01

    Both 2-[(2,4-dichlorophenoxy)acetoxy](methy)lmethyl-5,5-dimethyl-1,3,2-dioxaphosphinan-2-one (termed as IIa) and 2-[(4-chloro-2-methyl-phenoxy)-acetoxy](methyl)methyl-5,5-dimethyl-1,3,2-dioxaphosphinan-2-one (termed as IIr) are novel herbicide candidates that positively affect herbicidal activity via the introduction of a phosphorus-containing heterocyclic ring. This report investigated the mechanism of IIa and IIr on weed control in the model plant Arabidopsis thaliana at physiological, ultrastructural and molecular levels. IIa and IIr significantly inhibited the growth of A. thaliana and altered its root structure by inhibiting energy metabolism and lipid or protein biosynthesis. These compounds also significantly affected the absorption of nitrogen and phosphorus by down-regulating the transcripts of nitrate transporter-related genes, ammonium transporter-related genes and phosphorus transporter-related genes.

  20. Transcriptional and metabolomic analysis of Ascophyllum nodosum mediated freezing tolerance in Arabidopsis thaliana

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    Nair Prasanth

    2012-11-01

    Full Text Available Abstract Background We have previously shown that lipophilic components (LPC of the brown seaweed Ascophyllum nodosum (ANE improved freezing tolerance in Arabidopsis thaliana. However, the mechanism(s of this induced freezing stress tolerance is largely unknown. Here, we investigated LPC induced changes in the transcriptome and metabolome of A. thaliana undergoing freezing stress. Results Gene expression studies revealed that the accumulation of proline was mediated by an increase in the expression of the proline synthesis genes P5CS1 and P5CS2 and a marginal reduction in the expression of the proline dehydrogenase (ProDH gene. Moreover, LPC application significantly increased the concentration of total soluble sugars in the cytosol in response to freezing stress. Arabidopsis sfr4 mutant plants, defective in the accumulation of free sugars, treated with LPC, exhibited freezing sensitivity similar to that of untreated controls. The 1H NMR metabolite profile of LPC-treated Arabidopsis plants exposed to freezing stress revealed a spectrum dominated by chemical shifts (δ representing soluble sugars, sugar alcohols, organic acids and lipophilic components like fatty acids, as compared to control plants. Additionally, 2D NMR spectra suggested an increase in the degree of unsaturation of fatty acids in LPC treated plants under freezing stress. These results were supported by global transcriptome analysis. Transcriptome analysis revealed that LPC treatment altered the expression of 1113 genes (5% in comparison with untreated plants. A total of 463 genes (2% were up regulated while 650 genes (3% were down regulated. Conclusion Taken together, the results of the experiments presented in this paper provide evidence to support LPC mediated freezing tolerance enhancement through a combination of the priming of plants for the increased accumulation of osmoprotectants and alteration of cellular fatty acid composition.

  1. Starch-related carbon fluxes in roots and leaves of Arabidopsis thaliana.

    Science.gov (United States)

    Malinova, Irina; Steup, Martin; Fettke, Joerg

    2011-07-01

    Both photoautotrophic and heterotrophic tissues from plants are capable of synthesizing and degrading starch. To analyse starch metabolism in the two types of tissue from the same plant, several starch-related mutants from Arabidopsis thaliana were grown hydroponically together with the respective wild type control. Starch contents, patterns of starch-related enzymes, and the monomer patterns of the cytosolic starch-related heteroglycans were determined. Based on the phenotypical data obtained, three comparisons were made: First, data from leaves and roots of the mutants were compared with the respective wild type controls. Secondly, data from leaves and roots from the same plant were compared. Third, we included data obtained from soil-grown plants and compared them with those from hydroponically grown plants. Thus, phenotypical features reflecting altered gene expression can be distinguished from those that are due to the specific growth conditions. Implications on the carbon fluxes in photoautotrophic and heterotrophic cells are discussed.

  2. AtKP1, a kinesin-like protein, mainly localizes to mitochondria in Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Kinesins and kinesin-like proteins (KLPs) constitute a large family of microtubule-based motors that play important roles in many fundamental cellular and developmental processes. To date, a number of kinesins or KLPs have been identified in plants including Arabidopsis thaliana. Here, a polyclonal antibody against AtKP1 (kinesin-like protein 1 in A.thaliana) was raised by injection the expressed AtKP1 specific C-terminal polypeptides in rabbits, and immunoblot analysis was conducted with the affinity-purified anti-AtKP1 antibody. The results indicated that this antibody recognized the AtKP1 fusion proteins expressed in E. coli and proteins of ~125 kDa in the soluble fractions of Arabidopsis extracts. The molecular weight was consistent with the calculated molecular weight based on deduced amino acids sequence of AtKP1. To acquire the subcellular localization of the protein, AtKP1 in Arabidopsis root cells was observed by indirect immunofluorescence microscopy. AtKP1 was localized to particle-like organelles in interphase or dividing cells, but not to mitotic microtubule arrays. Relatively more AtKP1 was found in isolated mitochondria fraction on immunoblot of the subcellular fractions. The AtKP1 protein could not be released following a 0.6 M KI washing,indicating that AtKP1 is tightly bind to mitochondria and might function associated with this kind of organelles.

  3. Natural genetic variation in Arabidopsis for responsiveness to plant growth-promoting rhizobacteria

    NARCIS (Netherlands)

    Wintermans, P.C.A.; Bakker, P.A.H.M.; Pieterse, C.M.J.

    2016-01-01

    The plant growth-promoting rhizobacterium (PGPR) Pseudomonas simiae WCS417r stimulates lateral root formation and increases shoot growth in Arabidopsis thaliana (Arabidopsis). These plant growth-stimulating effects are partly caused by volatile organic compounds (VOCs) produced by the bacterium.

  4. Protein-protein interaction network and subcellular localization of the Arabidopsis thaliana ESCRT machinery

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    Lynn eRichardson

    2011-06-01

    Full Text Available The Endosomal Sorting Complex Required for Transport (ESCRT consists of several multi-protein subcomplexes which assemble sequentially at the endosomal surface and function in multivesicular body (MVB biogenesis. While ESCRT has been relatively well characterized in yeasts and mammals, comparably little is known about ESCRT in plants. Here we explored the yeast two-hybrid protein interaction network and subcellular localization of the Arabidopsis thaliana ESCRT machinery. We show that Arabidopsis ESCRT interactome possess a number of protein-protein interactions that are either conserved in yeasts and mammals or distinct to plants. We show also that most of the Arabidopsis ESCRT proteins examined at least partially localize to MVBs in plant cells when ectopically expressed on their own or co-expressed with other interacting ESCRT proteins, and some also induce abnormal MVB phenotypes, consistent with their proposed functional roles in MVB biogenesis. Overall, our results help define the plant ESCRT machinery by highlighting both conserved and unique features when compared to ESCRT in other evolutionarily diverse organisms, providing a foundation for further exploration of ESCRT in plants.

  5. A workflow for mathematical modeling of subcellular metabolic pathways in leaf metabolism of Arabidopsis thaliana

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    Thomas eNägele

    2013-12-01

    Full Text Available During the last decade genome sequencing has experienced a rapid technological development resulting in numerous sequencing projects and applications in life science. In plant molecular biology, the availability of sequence data on whole genomes has enabled the reconstruction of metabolic networks. Enzymatic reactions are predicted by the sequence information. Pathways arise due to the participation of chemical compounds as substrates and products in these reactions. Although several of these comprehensive networks have been reconstructed for the genetic model plant Arabidopsis thaliana, the integration of experimental data is still challenging. Particularly the analysis of subcellular organization of plant cells limits the understanding of regulatory instances in these metabolic networks in vivo. In this study, we develop an approach for the functional integration of experimental high-throughput data into such large-scale networks. We present a subcellular metabolic network model comprising 524 metabolic intermediates and 548 metabolic interactions derived from a total of 2769 reactions. We demonstrate how to link the metabolite covariance matrix of different Arabidopsis thaliana accessions with the subcellular metabolic network model for the inverse calculation of the biochemical Jacobian, finally resulting in the calculation of a matrix which satisfies a Lyaponov equation involving a covariance matrix. In this way, differential strategies of metabolite compartmentation and involved reactions were identified in the accessions when exposed to low temperature.

  6. Functional interactome of Aquaporin 1 sub-family reveals new physiological functions in Arabidopsis Thaliana

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    Mohamed Ragab Abdel Gawwad

    2013-09-01

    Full Text Available Aquaporins are channel proteins found in plasma membranes and intercellular membranes of different cellular compartments, facilitate the water flux, solutes and gases across the cellular plasma membranes. The present study highlights the sub-family plasma membrane intrinsic protein (PIP predicting the 3-D structure and analyzing the functional interactome of it homologs. PIP1 homologs integrate with many proteins with different plant physiological roles in Arabidopsis thaliana including; PIP1A and PIP1B: facilitate the transport of water, diffusion of amino acids and/or peptides from the vacuolar compartment to the cytoplasm, play a role in the control of cell turgor and cell expansion and involved in root water uptake respectively. In addition we found that PIP1B plays a defensive role against Pseudomonas syringae infection through the interaction with the plasma membrane Rps2 protein. Another substantial function of PIP1C via the interaction with PIP2E is the response to nematode infection. Generally, PIP1 sub-family interactome controlling many physiological processes in plant cell like; osmoregulation in plants under high osmotic stress such as under a high salt, response to nematode, facilitate the transport of water across cell membrane and regulation of floral initiation in Arabidopsis thaliana.

  7. Visualization of site-specific recombination catalyzed by a recombinase from Zygosaccharomyces rouxii in Arabidopsis thaliana.

    Science.gov (United States)

    Onouchi, H; Nishihama, R; Kudo, M; Machida, Y; Machida, C

    1995-06-25

    Excision of a DNA segment can occur in Arabidopsis thaliana by reciprocal recombination between two specific recombination sites (RSs) when the recombinase gene (R) from Zygosaccharomyces rouxii is expressed in the plant. To monitor recombination events, we generated several lines of transgenic Arabidopsis plants that carried a cryptic beta-glucuronidase (GUS) reporter gene which was designed in such a way that expression of the reporter gene could be induced by R gene-mediated recombination. We also made several transgenic lines with an R gene linked to the 35S promoter of cauliflower mosaic virus. Each transgenic line carrying the cryptic reporter gene was crossed with each line carrying the R gene. Activity of GUS in F1 and F2 progeny was examined histochemically and recombination between two RSs was analyzed by Southern blotting and the polymerase chain reaction. In seedlings and plantlets of F1 progeny and most of the F2 progeny, a variety of patterns of activity of GUS, including sectorial chimerism in leaves, was observed. A small percentage of F2 individuals exhibited GUS activity in the entire plant. This pattern of expression was ascribed to germinal recombination in the F1 generation on the basis of an analysis of DNA structure by Southern blotting. These results indicate that R gene-mediated recombination can be induced in both somatic and germ cells of A. thaliana by cross-pollination of parental transgenic lines.

  8. The FANTASTIC FOUR proteins influence shoot meristem size in Arabidopsis thaliana

    Science.gov (United States)

    2010-01-01

    Background Throughout their lives plants produce new organs from groups of pluripotent cells called meristems, located at the tips of the shoot and the root. The size of the shoot meristem is tightly controlled by a feedback loop, which involves the homeodomain transcription factor WUSCHEL (WUS) and the CLAVATA (CLV) proteins. This regulatory circuit is further fine-tuned by morphogenic signals such as hormones and sugars. Results Here we show that a family of four plant-specific proteins, encoded by the FANTASTIC FOUR (FAF) genes, has the potential to regulate shoot meristem size in Arabidopsis thaliana. FAF2 and FAF4 are expressed in the centre of the shoot meristem, overlapping with the site of WUS expression. Consistent with a regulatory interaction between the FAF gene family and WUS, our experiments indicate that the FAFs can repress WUS, which ultimately leads to an arrest of meristem activity in FAF overexpressing lines. The finding that meristematic expression of FAF2 and FAF4 is under negative control by CLV3 further supports the hypothesis that the FAFs are modulators of the genetic circuit that regulates the meristem. Conclusion This study reports the initial characterization of the Arabidopsis thaliana FAF gene family. Our data indicate that the FAF genes form a plant specific gene family, the members of which have the potential to regulate the size of the shoot meristem by modulating the CLV3-WUS feedback loop. PMID:21176196

  9. Temporal variation in genetic diversity and effective population size of Mediterranean and subalpine Arabidopsis thaliana populations.

    Science.gov (United States)

    Gomaa, Nasr H; Montesinos-Navarro, Alicia; Alonso-Blanco, Carlos; Picó, F Xavier

    2011-09-01

    Currently, there exists a limited knowledge on the extent of temporal variation in population genetic parameters of natural populations. Here, we study the extent of temporal variation in population genetics by genotyping 151 genome-wide SNP markers polymorphic in 466 individuals collected from nine populations of the annual plant Arabidopsis thaliana during 4 years. Populations are located along an altitudinal climatic gradient from Mediterranean to subalpine environments in NE Spain, which has been shown to influence key demographic attributes and life cycle adaptations. Genetically, A. thaliana populations were more variable across space than over time. Common multilocus genotypes were detected several years in the same population, whereas low-frequency multilocus genotypes appeared only 1 year. High-elevation populations were genetically poorer and more variable over time than low-elevation populations, which might be caused by a higher overall demographic instability at higher altitudes. Estimated effective population sizes were low but also showed a significant decreasing trend with increasing altitude, suggesting a deeper impact of genetic drift at high-elevation populations. In comparison with single-year samplings, repeated genotyping over time captured substantially higher amount of genetic variation contained in A. thaliana populations. Furthermore, repeated genotyping of populations provided novel information on the genetic properties of A. thaliana populations and allowed hypothesizing on their underlying mechanisms. Therefore, including temporal genotyping programmes into traditional population genetic studies can significantly increase our understanding of the dynamics of natural populations.

  10. Arabidopsis thaliana model system reveals a continuum of responses to root endophyte colonization.

    Science.gov (United States)

    Mandyam, Keerthi G; Roe, Judith; Jumpponen, Ari

    2013-04-01

    We surveyed the non-mycorrhizal model plant Arabidopsis thaliana microscopically for its ability to form dark septate endophyte (DSE) symbioses in field, greenhouse, and laboratory studies. The laboratory studies were also used to estimate host growth responses to 34 Periconia macrospinosa and four Microdochium sp. isolates. Consistent with broad host range observed in previous experiments, field-, greenhouse-, and laboratory-grown A. thaliana were colonized by melanized inter- and intracellular hyphae and microsclerotia or chlamydospores indicative of DSE symbiosis. Host responses to colonization were variable and depended on the host ecotype. On average, two A. thaliana accessions (Col-0 and Cvi-0) responded negatively, whereas one (Kin-1) was unresponsive, a conclusion consistent with our previous analyses with forbs native to the field site where the fungi originate. Despite the average negative responses, examples of positive responses were also observed, a conclusion also congruent with earlier studies. Our results suggest that A. thaliana has potential as a model for more detailed dissection of the DSE symbiosis. Furthermore, our data suggest that host responses are controlled by variability in the host and endophyte genotypes.

  11. Raphanusanin-mediated resistance to pathogens is light dependent in radish and Arabidopsis thaliana.

    Science.gov (United States)

    Moehninsi; Miura, Kenji; Yamada, Kosumi; Shigemori, Hideyuki

    2014-09-01

    Raphanusanin (Ra) is a light-induced inhibitor of hypocotyl growth that responds to unilateral blue light illumination in radish seedlings. We have previously shown that Ra regulates genes that are involved in common defense mechanisms. Many genes that are induced by Ra are also positively regulated by early blue light. To extend the understanding of the role of Ra in pathogen defense, we evaluated the effects of Ra on radish and Arabidopsis thaliana (A. thaliana) infected with the necrotrophic pathogen Botrytis cinerea (B. cinerea) and biotrophic pathogen Pseudomonas syringae (P. syringae). Radish and A. thaliana were found to be resistant to both pathogens when treated with Ra, depending on the concentration used. Interestingly, Ra-mediated resistance to P. syringae is dependent on light because Ra-treated seedlings exhibited enhanced susceptibility to P. syringae infection when grown in the dark. In addition to regulating the biotic defense response, Ra inhibited seed germination and root elongation and enhanced the growth of root hairs in the presence of light in radish and A. thaliana. Our data suggest that Ra regulates the expression of a set of genes involved in defense signaling pathways and plays a role in pathogen defense and plant development. Our results show that light may be generally required not only for the accumulation of Ra but also for its activation during the pathogen defense response.

  12. Trafficking of endoplasmic reticulum-retained recombinant proteins is unpredictable in Arabidopsis thaliana

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    Thomas eDe Meyer

    2014-09-01

    Full Text Available A wide variety of recombinant proteins has been produced in the dicot model plant, Arabidopsis thaliana. Many of these proteins are targeted for secretion by means of an N terminal endoplasmic reticulum (ER signal peptide. In addition, they can also be designed for ER retention by adding a C terminal H/KDEL-tag. Despite extensive knowledge of the protein trafficking pathways, the final protein destination, especially of such H/KDEL-tagged recombinant proteins, is unpredictable. In this respect, glycoproteins are ideal study objects. Microscopy experiments reveal their deposition pattern and characterization of their N-glycans aids in elucidating the trafficking. Here, we combine microscopy and N glycosylation data generated in Arabidopsis leaves and seeds, and highlight the lack of a decent understanding of heterologous protein trafficking.

  13. An intergenic region shared by At4g35985 and At4g35987 in Arabidopsis thaliana is a tissue specific and stress inducible bidirectional promoter analyzed in transgenic arabidopsis and tobacco plants.

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    Joydeep Banerjee

    Full Text Available On chromosome 4 in the Arabidopsis genome, two neighboring genes (calmodulin methyl transferase At4g35987 and senescence associated gene At4g35985 are located in a head-to-head divergent orientation sharing a putative bidirectional promoter. This 1258 bp intergenic region contains a number of environmental stress responsive and tissue specific cis-regulatory elements. Transcript analysis of At4g35985 and At4g35987 genes by quantitative real time PCR showed tissue specific and stress inducible expression profiles. We tested the bidirectional promoter-function of the intergenic region shared by the divergent genes At4g35985 and At4g35987 using two reporter genes (GFP and GUS in both orientations in transient tobacco protoplast and Agro-infiltration assays, as well as in stably transformed transgenic Arabidopsis and tobacco plants. In transient assays with GFP and GUS reporter genes the At4g35985 promoter (P85 showed stronger expression (about 3.5 fold compared to the At4g35987 promoter (P87. The tissue specific as well as stress responsive functional nature of the bidirectional promoter was evaluated in independent transgenic Arabidopsis and tobacco lines. Expression of P85 activity was detected in the midrib of leaves, leaf trichomes, apical meristemic regions, throughout the root, lateral roots and flowers. The expression of P87 was observed in leaf-tip, hydathodes, apical meristem, root tips, emerging lateral root tips, root stele region and in floral tissues. The bidirectional promoter in both orientations shows differential up-regulation (2.5 to 3 fold under salt stress. Use of such regulatory elements of bidirectional promoters showing spatial and stress inducible promoter-functions in heterologous system might be an important tool for plant biotechnology and gene stacking applications.

  14. FUM2, a Cytosolic Fumarase, Is Essential for Acclimation to Low Temperature in Arabidopsis thaliana.

    Science.gov (United States)

    Dyson, Beth C; Miller, Matthew A E; Feil, Regina; Rattray, Nicholas; Bowsher, Caroline G; Goodacre, Royston; Lunn, John E; Johnson, Giles N

    2016-09-01

    Although cold acclimation is a key process in plants from temperate climates, the mechanisms sensing low temperature remain obscure. Here, we show that the accumulation of the organic acid fumaric acid, mediated by the cytosolic fumarase FUM2, is essential for cold acclimation of metabolism in the cold-tolerant model species Arabidopsis (Arabidopsis thaliana). A nontargeted metabolomic approach, using gas chromatography-mass spectrometry, identifies fumarate as a key component of the cold response in this species. Plants of T-DNA insertion mutants, lacking FUM2, show marked differences in their response to cold, with contrasting responses both in terms of metabolite concentrations and gene expression. The fum2 plants accumulated higher concentrations of phosphorylated sugar intermediates and of starch and malate. Transcripts for proteins involved in photosynthesis were markedly down-regulated in fum2.2 but not in wild-type Columbia-0. Plants of fum2 show a complete loss of the ability to acclimate photosynthesis to low temperature. We conclude that fumarate accumulation plays an essential role in low temperature sensing in Arabidopsis, either indirectly modulating metabolic or redox signals or possibly being itself directly involved in cold sensing.

  15. Herbicide-resistance conferred by expression of a catalytic antibody in Arabidopsis thaliana.

    Science.gov (United States)

    Weiss, Yael; Shulman, Avidor; Ben Shir, Irina; Keinan, Ehud; Wolf, Shmuel

    2006-06-01

    Engineering herbicide resistance in crops facilitates control of weed species, particularly those that are closely related to the crop, and may be useful in selecting lines that have undergone multiple transformation events. Here we show that herbicide-resistant plants can be engineered by designing an herbicide and expressing a catalytic antibody that destroys the herbicide in planta. First, we developed a carbamate herbicide that can be catalytically destroyed by the aldolase antibody 38C2. This compound has herbicidal activity on all three plant species tested. Second, the light chain and half of the heavy chain (Fab) of the catalytic antibody were targeted to the endoplasmic reticulum in two classes of Arabidopsis thaliana transformants. Third, the two transgenic plants were crossed to produce an herbicide-resistant F1 hybrid. The in vitro catalytic activity of the protein from F1 hybrids corroborates that catalytic antibodies can be constitutively expressed in transgenic plants, and that they can confer a unique trait.

  16. Bacillus subtilis Early Colonization of Arabidopsis thaliana Roots Involves Multiple Chemotaxis Receptors.

    Science.gov (United States)

    Allard-Massicotte, Rosalie; Tessier, Laurence; Lécuyer, Frédéric; Lakshmanan, Venkatachalam; Lucier, Jean-François; Garneau, Daniel; Caudwell, Larissa; Vlamakis, Hera; Bais, Harsh P; Beauregard, Pascale B

    2016-11-29

    Colonization of plant roots by Bacillus subtilis is mutually beneficial to plants and bacteria. Plants can secrete up to 30% of their fixed carbon via root exudates, thereby feeding the bacteria, and in return the associated B. subtilis bacteria provide the plant with many growth-promoting traits. Formation of a biofilm on the root by matrix-producing B. subtilis is a well-established requirement for long-term colonization. However, we observed that cells start forming a biofilm only several hours after motile cells first settle on the plant. We also found that intact chemotaxis machinery is required for early root colonization by B. subtilis and for plant protection. Arabidopsis thaliana root exudates attract B. subtilis in vitro, an activity mediated by the two characterized chemoreceptors, McpB and McpC, as well as by the orphan receptor TlpC. Nonetheless, bacteria lacking these chemoreceptors are still able to colonize the root, suggesting that other chemoreceptors might also play a role in this process. These observations suggest that A. thaliana actively recruits B. subtilis through root-secreted molecules, and our results stress the important roles of B. subtilis chemoreceptors for efficient colonization of plants in natural environments. These results demonstrate a remarkable strategy adapted by beneficial rhizobacteria to utilize carbon-rich root exudates, which may facilitate rhizobacterial colonization and a mutualistic association with the host.

  17. Bacillus subtilis Early Colonization of Arabidopsis thaliana Roots Involves Multiple Chemotaxis Receptors

    Directory of Open Access Journals (Sweden)

    Rosalie Allard-Massicotte

    2016-11-01

    Full Text Available Colonization of plant roots by Bacillus subtilis is mutually beneficial to plants and bacteria. Plants can secrete up to 30% of their fixed carbon via root exudates, thereby feeding the bacteria, and in return the associated B. subtilis bacteria provide the plant with many growth-promoting traits. Formation of a biofilm on the root by matrix-producing B. subtilis is a well-established requirement for long-term colonization. However, we observed that cells start forming a biofilm only several hours after motile cells first settle on the plant. We also found that intact chemotaxis machinery is required for early root colonization by B. subtilis and for plant protection. Arabidopsis thaliana root exudates attract B. subtilis in vitro, an activity mediated by the two characterized chemoreceptors, McpB and McpC, as well as by the orphan receptor TlpC. Nonetheless, bacteria lacking these chemoreceptors are still able to colonize the root, suggesting that other chemoreceptors might also play a role in this process. These observations suggest that A. thaliana actively recruits B. subtilis through root-secreted molecules, and our results stress the important roles of B. subtilis chemoreceptors for efficient colonization of plants in natural environments. These results demonstrate a remarkable strategy adapted by beneficial rhizobacteria to utilize carbon-rich root exudates, which may facilitate rhizobacterial colonization and a mutualistic association with the host.

  18. Efeito das xiloglucanas de sementes e derivados no crescimento de Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Adriana Tourinho Salamoni

    2008-01-01

    Full Text Available Studies on xyloglucan (XG extracted from Hymenaea courbaril L. (jatoba seeds showed that this biopolymer has biological activity that enhanced wheat coleoptiles growth. In apple tree micropropagation, the culture medium containing XG combined with agar induced a higher multiplication rate, rooting rate and root length than medium solidified with agar only. The purpose of this study was to determine the effect of XG from jatobá seeds extracted from jatoba seeds collected in Sinope/MT (XGS and Cuiabá/MT (XGC, and from XGC hydrolysed with a cellulase (XGCH, as well from Tamarindus indica seeds (XGT collected in Bahia/BA, on the growth of in vitro cultured Arabidopsis thaliana plantlets. In the first experiment, XGCH (0.25, 25 and 250 nM or XGC (0.5, 50 and 500 nM were added to a liquid half-strength MS medium. In the second experiment, XGs from several origins were compared: XGC (500 nM, XGS (1200 nM and XGT (800 nM, using culture medium solidified with 6 g.L-1agar. Arabidopsis thaliana L. seeds germinated in Petri plates for 4 to 5 days were transferred to culture media containing the different concentrations of XGs and cultured in a growing room. When the plantlets were cultured in a liquid medium, their growth was very slow in the presence of XGC and XGCH at the highest concentration tested, and it was faster at the lowest concentration. In the semi-solid culture medium, XGs also reduced growth. It was concluded that XGs can play a biological role in Arabidopsis thaliana (L. Heynh. plantlets, stimulating or inhibiting the root system growth and the lateral root formation. These opposite effects varied according to the plant specie that furnished the seeds containing XG, as well as the place where the seeds were collected, to the XG form used (hydrolyzed or not and to its concentration in the culture media.

  19. Reconstruction and analysis of nutrient-induced phosphorylation networks in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Guangyou eDuan

    2013-12-01

    Full Text Available Elucidating the dynamics of molecular processes in living organisms in response to external perturbations is a central goal in modern systems biology. We investigated the dynamics of protein phosphorylation events in Arabidopsis thaliana exposed to changing nutrient conditions. Phosphopeptide expression levels were detected at five consecutive time points over a time interval of 30 minutes after nutrient resupply following prior starvation. The three tested inorganic, ionic nutrients NH4+, NO3-, PO43- elicited similar phosphosignaling responses that were distinguishable from those invoked by the sugars mannitol, sucrose. When embedded in the protein-protein interaction network of Arabidopsis thaliana, phosphoproteins were found to exhibit a higher degree compared to average proteins. Based on the time-series data, we reconstructed a network of regulatory interactions mediated by phosphorylation. The performance of different network inference methods was evaluated by the observed likelihood of physical interactions within and across different subcellular compartments and based on gene ontology semantic similarity. The dynamic phosphorylation network was then reconstructed using a Pearson correlation method with added directionality based on partial variance differences. The topology of the inferred integrated network corresponds to an information dissemination architecture, in which the phosphorylation signal is passed on to an increasing number of phosphoproteins stratified into an initiation, processing, and effector layer. Specific phosphorylation peptide motifs associated with the distinct layers were identified indicating the action of layer-specific kinases. Despite the limited temporal resolution, combined with information on subcellular location, the available time-series data proved useful for reconstructing the dynamics of the molecular signaling cascade in response to nutrient stress conditions in the plant Arabidopsis thaliana.

  20. Enhanced homologous recombination is induced by alpha-particle radiation in somatic cells of Arabidopsis thaliana

    Science.gov (United States)

    Bian, Po; Liu, Ping; Wu, Yuejin

    Almost 9 percent of cosmic rays which strike the earth's atmosphere are alpha particles. As one of the ionizing radiations (IR), its biological effects have been widely studied. However, the plant genomic instability induced by alpha-particle radiation was not largely known. In this research, the Arabidopsis thaliana transgenic for GUS recombination substrate was used to evaluate the genomic instability induced by alpha-particle radiation (3.3MeV). The pronounced effects of systemic exposure to alpha-particle radiation on the somatic homologous recombination frequency (HRF) were found at different doses. The 10Gy dose of radiation induced the maximal HRF which was 1.9-fold higher than the control. The local radiation of alpha-particle (10Gy) on root also resulted in a 2.5-fold increase of somatic HRF in non-radiated aerial plant, indicating that the signal(s) of genomic instability was transferred to non-radiated parts and initiated their genomic instability. Concurrent treatment of seedlings of Arabidopsis thaliana with alpha-particle and DMSO(ROS scavenger) both in systemic and local radiation signifi- cantly suppressed the somatic HR, indicating that the free radicals produced by alpha-particle radiation took part in the production of signal of genomic instability rather than the signal transfer. Key words: alpha-particle radiation, somatic homologous recombination, genomic instability

  1. Effect of endocrine disruptor nonylphenol on physiologic features and proteome during growth in Arabidopsis thaliana.

    Science.gov (United States)

    Chen, Bing-Sheng; Yen, Jui-Hung

    2013-04-01

    We studied the effects of nonylphenol (NP) on physiological features and proteome of Arabidopsis (Arabidopsis thaliana) during growth. Shoot biomass, root biomass and root length were decreased after 10d of NP treatment, especially in high NP concentration treatment (10 and 50 mg L(-1)). Levels of chlorophyll decreased but proline increased in leaves. NP caused oxidative stress; malondialdehyde content was increased with NP treatment, and the activities of ascorbate peroxidase, catalase, CuZnSOD and MnSOD were induced in leaves. The proteome of leaf tissue was analyzed by 2-D gel electrophoresis and mass spectrometry. NP might adversely affect the CO2 assimilation, signal transduction, the endomembrane system and photosynthetic oxygen evolution. NP affects the proteome and physiologic and morphological features of A. thaliana during growth at the concentration can be observed in the environment. Because plants might be exposed to NP for a long time in the surroundings, more attention needs to be paid to the effect of NP on plants. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. AraPheno: a public database for Arabidopsis thaliana phenotypes

    Science.gov (United States)

    Seren, Ümit; Grimm, Dominik; Fitz, Joffrey; Weigel, Detlef; Nordborg, Magnus; Borgwardt, Karsten; Korte, Arthur

    2017-01-01

    Natural genetic variation makes it possible to discover evolutionary changes that have been maintained in a population because they are advantageous. To understand genotype–phenotype relationships and to investigate trait architecture, the existence of both high-resolution genotypic and phenotypic data is necessary. Arabidopsis thaliana is a prime model for these purposes. This herb naturally occurs across much of the Eurasian continent and North America. Thus, it is exposed to a wide range of environmental factors and has been subject to natural selection under distinct conditions. Full genome sequencing data for more than 1000 different natural inbred lines are available, and this has encouraged the distributed generation of many types of phenotypic data. To leverage these data for meta analyses, AraPheno (https://arapheno.1001genomes.org) provide a central repository of population-scale phenotypes for A. thaliana inbred lines. AraPheno includes various features to easily access, download and visualize the phenotypic data. This will facilitate a comparative analysis of the many different types of phenotypic data, which is the base to further enhance our understanding of the genotype–phenotype map. PMID:27924043

  3. Burkholderia phytofirmans PsJN reduces damages to freezing temperature in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Fan eSU

    2015-10-01

    Full Text Available Several plant growth-promoting rhizobacteria (PGPR are known to improve plant tolerance to multiple stresses, including low temperatures. However, mechanisms underlying this protection are still poorly understood. The aim of this study was to evaluate the role of the endophytic PGPR, Burkholderia phytofirmans strain PsJN (Bp PsJN, on Arabidopsis thaliana cold tolerance using photosynthesis parameters as physiological markers.Under standard conditions, our results indicated that Bp PsJN inoculation led to growth promotion of Arabidopsis plants without significant modification on photosynthesis parameters and chloroplast organization. However, bacterial colonization induced a cell wall strengthening in the mesophyllImpact of inoculation modes (either on seeds or by soil irrigation and their effects overnight at 0, -1 or -3°C, were investigated by following photosystem II (PSII activity and gas exchanges. Following low temperatures stress, a decrease of photosynthesis parameters was observed. In addition, during three consecutive nights or days at -1°C, PSII activity was monitored. Pigment contents, RuBisCO protein abundance, expression of several genes including RbcS, RbcL, CBF1, CBF2, CBF3, ICE1, COR15a, and COR78 were evaluated at the end of exposure. To assess the impact of the bacteria on cell ultrastructure under low temperatures, microscopic observations were achieved. Results indicated that freezing treatment induced significant changes in PSII activity as early as the first cold day, whereas the same impact on PSII activity was observed only during the third cold night. The significant effects conferred by PsJN were differential accumulation of pigments, and reduced expression of RbcL and COR78. Microscopical observations showed an alteration/disorganization in A. thaliana leaf mesophyll cells independently of the freezing treatments. The presence of bacteria during the three successive nights or days did not significantly improved A

  4. Differential remodeling of the lipidome during cold acclimation in natural accessions of Arabidopsis thaliana.

    Science.gov (United States)

    Degenkolbe, Thomas; Giavalisco, Patrick; Zuther, Ellen; Seiwert, Bettina; Hincha, Dirk K; Willmitzer, Lothar

    2012-12-01

    Freezing injury is a major factor limiting the geographical distribution of plant species and the growth and yield of crop plants. Plants from temperate climates are able to increase their freezing tolerance during exposure to low but non-freezing temperatures in a process termed cold acclimation. Damage to cellular membranes is the major cause of freezing injury in plants, and membrane lipid composition is strongly modified during cold acclimation. Forward and reverse genetic approaches have been used to probe the role of specific lipid-modifying enzymes in the freezing tolerance of plants. In the present paper we describe an alternative ecological genomics approach that relies on the natural genetic variation within a species. Arabidopsis thaliana has a wide geographical range throughout the Northern Hemisphere with significant natural variation in freezing tolerance that was used for a comparative analysis of the lipidomes of 15 Arabidopsis accessions using ultra-performance liquid chromatography coupled to Fourier-transform mass spectrometry, allowing the detection of 180 lipid species. After 14 days of cold acclimation at 4°C the plants from most accessions had accumulated massive amounts of storage lipids, with most of the changes in long-chain unsaturated triacylglycerides, while the total amount of membrane lipids was only slightly changed. Nevertheless, major changes in the relative amounts of different membrane lipids were also evident. The relative abundance of several lipid species was highly correlated with the freezing tolerance of the accessions, allowing the identification of possible marker lipids for plant freezing tolerance.

  5. Characterization of Arabidopsis thaliana pinoresinol reductase, a new type of enzyme involved in lignan biosynthesis.

    Science.gov (United States)

    Nakatsubo, Tomoyuki; Mizutani, Masaharu; Suzuki, Shiro; Hattori, Takefumi; Umezawa, Toshiaki

    2008-06-01

    A lignan, lariciresinol, was isolated from Arabidopsis thaliana, the most widely used model plant in plant bioscience sectors, for the first time. In the A. thaliana genome database, there are two genes (At1g32100 and At4g13660) that are annotated as pinoresinol/lariciresinol reductase (PLR). The recombinant AtPLRs showed strict substrate preference toward pinoresinol but only weak or no activity toward lariciresinol, which is in sharp contrast to conventional PLRs of other plants that can reduce both pinoresinol and lariciresinol efficiently to lariciresinol and secoisolariciresinol, respectively. Therefore, we renamed AtPLRs as A. thaliana pinoresinol reductases (AtPrRs). The recombinant AtPrR2 encoded by At4g13660 reduced only (-)-pinoresinol to (-)-lariciresinol and not (+)-pinoresinol in the presence of NADPH. This enantiomeric selectivity accords with that of other PLRs of other plants so far reported, which can reduce one of the enantiomers selectively, whatever the preferential enantiomer. In sharp contrast, AtPrR1 encoded by At1g32100 reduced both (+)- and (-)-pinoresinols to (+)- and (-)-lariciresinols efficiently with comparative k(cat)/K(m) values. Analysis of lignans and spatiotemporal expression of AtPrR1 and AtPrR2 in their functionally deficient A. thaliana mutants and wild type indicated that both genes are involved in lariciresinol biosynthesis. In addition, the analysis of the enantiomeric compositions of lariciresinol isolated from the mutants and wild type showed that PrRs together with a dirigent protein(s) are involved in the enantiomeric control in lignan biosynthesis. Furthermore, it was demonstrated conclusively for the first time that differential expression of PrR isoforms that have distinct selectivities of substrate enantiomers can determine enantiomeric compositions of the product, lariciresinol.

  6. Expression of pH-sensitive green fluorescent protein in Arabidopsis thaliana

    Science.gov (United States)

    Moseyko, N.; Feldman, L. J.

    2001-01-01

    This is the first report on using green fluorescent protein (GFP) as a pH reporter in plants. Proton fluxes and pH regulation play important roles in plant cellular activity and therefore, it would be extremely helpful to have a plant gene reporter system for rapid, non-invasive visualization of intracellular pH changes. In order to develop such a system, we constructed three vectors for transient and stable transformation of plant cells with a pH-sensitive derivative of green fluorescent protein. Using these vectors, transgenic Arabidopsis thaliana and tobacco plants were produced. Here the application of pH-sensitive GFP technology in plants is described and, for the first time, the visualization of pH gradients between different developmental compartments in intact whole-root tissues of A. thaliana is reported. The utility of pH-sensitive GFP in revealing rapid, environmentally induced changes in cytoplasmic pH in roots is also demonstrated.

  7. Genetic analysis of a host determination mechanism of bromoviruses in Arabidopsis thaliana.

    Science.gov (United States)

    Fujisaki, Koki; Iwahashi, Fukumatsu; Kaido, Masanori; Okuno, Tetsuro; Mise, Kazuyuki

    2009-03-01

    Brome mosaic virus (BMV) and Spring beauty latent virus (SBLV) are closely related, tripartite RNA plant viruses. In Arabidopsis thaliana, BMV shows limited multiplication whereas SBLV efficiently multiplies. Such distinct multiplication abilities have been observed commonly in all Arabidopsis accessions tested. We used this model system to analyze the molecular mechanism of viral resistance in plants at the species level. Unlike SBLV, BMV multiplication was limited even in protoplasts and a reassortment assay indicated that at least viral RNA1 and/or RNA2 determine such distinct infectivities. By screening Arabidopsis mutants with altered defense responses, we found that BMV multiplies efficiently in cpr5-2 mutant plants. This mutation specifically enhanced BMV multiplication in protoplasts, which depended on the functions of RNA1 and RNA2. In the experiment using DNA vectors to express BMV replication proteins encoded by RNA1 and RNA2, BMV RNA3 accumulation in cpr5-2 protoplasts was similar to that in wild-type Col-0 protoplasts, despite significant reduction of accumulation levels of replication proteins, suggesting that cpr5-2 mutation could enhance BMV multiplication independently of increased accumulation, therefore enhanced translation and stabilization, of the replication proteins.

  8. Proteomic analysis of Arabidopsis thaliana (L.) Heynh responses to a generalist sucking pest (Myzus persicae Sulzer).

    Science.gov (United States)

    Truong, D-H; Bauwens, J; Delaplace, P; Mazzucchelli, G; Lognay, G; Francis, F

    2015-11-01

    Herbivorous insects can cause severe cellular changes to plant foliage following infestations, depending on feeding behaviour. Here, a proteomic study was conducted to investigate the influence of green peach aphid (Myzus persicae Sulzer) as a polyphagous pest on the defence response of Arabidopsis thaliana (L.) Heynh after aphid colony establishment on the host plant (3 days). Analysis of about 574 protein spots on 2-DE gels revealed 31 differentially expressed protein spots. Twenty out of these 31 differential proteins were selected for analysis by mass spectrometry. In 12 of the 20 analysed spots, we identified seven and nine proteins using MALDI-TOF-MS and LC-ESI-MS/MS, respectively. Of the analysed spots, 25% contain two proteins. Different metabolic pathways were modulated in Arabidopsis leaves according to aphid feeding: most corresponded to carbohydrate, amino acid and energy metabolism, photosynthesis, defence response and translation. This paper has established a survey of early alterations induced in the proteome of Arabidopsis by M. persicae aphids. It provides valuable insights into the complex responses of plants to biological stress, particularly for herbivorous insects with sucking feeding behaviour.

  9. DEWAX Transcription Factor Is Involved in Resistance to Botrytis cinerea in Arabidopsis thaliana and Camelina sativa

    Directory of Open Access Journals (Sweden)

    Seulgi Ju

    2017-07-01

    Full Text Available The cuticle of land plants is the first physical barrier to protect their aerial parts from biotic and abiotic stresses. DEWAX, an AP2/ERF-type transcription factor, negatively regulates cuticular wax biosynthesis. In this study, we investigated the resistance to Botrytis cinerea in Arabidopsis thaliana and Camelina sativa overexpressing DEWAX and in Arabidopsis dewax mutant. Compared to wild type (WT leaves, Arabidopsis DEWAX OX and dewax leaves were more and less permeable to toluidine blue dye, respectively. The ROS levels increased in DEWAX OX leaves, but decreased in dewax relative to WT leaves. Compared to WT, DEWAX OX was more resistant, while dewax was more sensitive to B. cinerea; however, defense responses to Pseudomonas syringae pv. tomato DC3000:GFP were inversely modulated. Microarray and RT-PCR analyses indicated that the expression of defense-related genes was upregulated in DEWAX OX, but downregulated in dewax relative to WT. Transactivation assay showed that DEWAX upregulated the expression of PDF1.2a, IGMT1, and PRX37. Chromatin immunoprecipitation assay revealed that DEWAX directly interacts with the GCC-box motifs of PDF1.2a promoter. In addition, ectopic expression of DEWAX increased the tolerance to B. cinerea in C. sativa. Taken together, we suggest that increased ROS accumulation and DEWAX-mediated upregulation of defense-related genes are closely associated with enhanced resistance to B. cinerea in Arabidopsis and C. sativa.

  10. Xylogalacturonan exists in cell walls from various tissues of Arabidopsis thaliana

    NARCIS (Netherlands)

    Zandleven, J.S.; Sorensen, S.; Harbolt, J.; Beldman, G.; Schols, H.A.; Scheller, H.V.; Voragen, A.G.J.

    2007-01-01

    Evidence is presented for the presence of xylogalacturonan (XGA) in Arabidopsis thaliana. This evidence was obtained by extraction of pectin from the seeds, root, stem, young leaves and mature leaves of A. thaliana, followed by treatment of these pectin extracts with xylogalacturonan hydrolase (XGH)

  11. ARABIDOPSIS THALIANA HOMEOBOX25 uncovers a role for Gibberellins in seed longevity.

    Science.gov (United States)

    Bueso, Eduardo; Muñoz-Bertomeu, Jesús; Campos, Francisco; Brunaud, Veronique; Martínez, Liliam; Sayas, Enric; Ballester, Patricia; Yenush, Lynne; Serrano, Ramón

    2014-02-01

    Seed longevity is crucial for agriculture and plant genetic diversity, but it is limited by cellular damage during storage. Seeds are protected against aging by cellular defenses and by structures such as the seed coat. We have screened an activation-tagging mutant collection of Arabidopsis (Arabidopsis thaliana) and selected four dominant mutants with improved seed longevity (isl1-1D to isl4-1D) under both natural and accelerated aging conditions. In the isl1-1D mutant, characterized in this work, overexpression of the transcription factor ARABIDOPSIS THALIANA HOMEOBOX25 (ATHB25; At5g65410) increases the expression of GIBBERELLIC ACID3-OXIDASE2, encoding a gibberellin (GA) biosynthetic enzyme, and the levels of GA1 and GA4 are higher (3.2- and 1.4-fold, respectively) in the mutant than in the wild type. The morphological and seed longevity phenotypes of the athb25-1D mutant were recapitulated in transgenic plants with moderate (4- to 6-fold) overexpression of ATHB25. Simultaneous knockdown of ATHB25, ATHB22, and ATHB31 expression decreases seed longevity, as does loss of ATHB25 and ATHB22 function in a double mutant line. Seeds from wild-type plants treated with GA and from a quintuple DELLA mutant (with constitutive GA signaling) are more tolerant to aging, providing additional evidence for a role of GA in seed longevity. A correlation was observed in several genotypes between seed longevity and mucilage formation at the seed surface, suggesting that GA may act by reinforcing the seed coat. This mechanism was supported by the observation of a maternal effect in reciprocal crosses between the wild type and the athb25-1D mutant.

  12. Expression of Cucumber mosaic virus suppressor 2b alters FWA methylation and its siRNA accumulation in Arabidopsis thaliana.

    Science.gov (United States)

    Hamera, Sadia; Yan, Youngsheng; Song, Xiaoguang; Chaudhary, Safee Ullah; Murtaza, Iram; Su, Lei; Tariq, Muhammad; Chen, Xiaoying; Fang, Rongxiang

    2016-11-15

    The Cucumber mosaic virus (CMV) suppressor 2b co-localizes with AGO4 in cytoplasmic and nuclear fractions of Arabidopsis thaliana Biochemical fractionation of A. thaliana cellular extracts revealed that 2b and AGO4 coexist in multiple size exclusions. 2b transgenic A. thaliana exhibited an enhanced accumulation of 24nt siRNAs from flowering wageningen (FWA) and other heterochromatic loci. These plants also exhibited hypo-methylation of an endogenous- as well as transgene-FWA promoter at non-CG sites. In corroboration, both transgenic 2b and CMV infection affected the regulation of transposons which mimics the ago4 phenotype. In conclusion, 2b perturbs plant defense by interfering with AGO4-regulated transcriptional gene silencing.

  13. Expression of Cucumber mosaic virus suppressor 2b alters FWA methylation and its siRNA accumulation in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Sadia Hamera

    2016-11-01

    Full Text Available The Cucumber mosaic virus (CMV suppressor 2b co-localizes with AGO4 in cytoplasmic and nuclear fractions of Arabidopsis thaliana. Biochemical fractionation of A. thaliana cellular extracts revealed that 2b and AGO4 coexist in multiple size exclusions. 2b transgenic A. thaliana exhibited an enhanced accumulation of 24nt siRNAs from flowering wageningen (FWA and other heterochromatic loci. These plants also exhibited hypo-methylation of an endogenous- as well as transgene-FWA promoter at non-CG sites. In corroboration, both transgenic 2b and CMV infection affected the regulation of transposons which mimics the ago4 phenotype. In conclusion, 2b perturbs plant defense by interfering with AGO4-regulated transcriptional gene silencing.

  14. The Structure of Sucrose Synthase-1 from Arabidopsis thaliana and Its Functional Implications

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Yi; Anderson, Spencer; Zhang, Yanfeng; Garavito, R. Michael (MSU); (NWU)

    2014-10-02

    Sucrose transport is the central system for the allocation of carbon resources in vascular plants. During growth and development, plants control carbon distribution by coordinating sites of sucrose synthesis and cleavage in different plant organs and different cellular locations. Sucrose synthase, which reversibly catalyzes sucrose synthesis and cleavage, provides a direct and reversible means to regulate sucrose flux. Depending on the metabolic environment, sucrose synthase alters its cellular location to participate in cellulose, callose, and starch biosynthesis through its interactions with membranes, organelles, and cytoskeletal actin. The x-ray crystal structure of sucrose synthase isoform 1 from Arabidopsis thaliana (AtSus1) has been determined as a complex with UDP-glucose and as a complex with UDP and fructose, at 2.8- and 2.85-{angstrom} resolutions, respectively. The AtSus1 structure provides insights into sucrose catalysis and cleavage, as well as the regulation of sucrose synthase and its interactions with cellular targets.

  15. Haemoglobin modulates NO emission and hyponasty under hypoxia-related stress in Arabidopsis thaliana

    DEFF Research Database (Denmark)

    Hebelstrup, Kim; van Zanten, Martijn; Mandon, Julien;

    2012-01-01

    Nitric oxide (NO) and ethylene are signalling molecules that are synthesized in response to oxygen depletion. Non-symbiotic plant haemoglobins (Hbs) have been demonstrated to act in roots under oxygen depletion to scavenge NO. Using Arabidopsis thaliana plants, the online emission of NO or ethylene...... represented a major loss of nitrogen equivalent to 0.2mM nitrate per 24h under hypoxic conditions. Hb gene expression was greatly enhanced in flooded roots, suggesting induction by reduced oxygen diffusion. The function could be to limit loss of nitrogen under NO emission. NO reacts with thiols to form S......-nitrosylated compounds, and it is demonstrated that hypoxia substantially increased the content of S-nitrosylated compounds. A parallel up-regulation of Hb gene expression in the normoxic shoots of the flooded plants may reflect signal transmission from root to shoot via ethylene and a role for Hb in the shoots. Hb gene...

  16. The influence of matrix attachment regions on transgene expression in Arabidopsis thaliana wild type and gene silencing mutants.

    Science.gov (United States)

    De Bolle, Miguel F C; Butaye, Katleen M J; Goderis, Inge J W M; Wouters, Piet F J; Jacobs, Anni; Delauré, Stijn L; Depicker, Ann; Cammue, Bruno P A

    2007-03-01

    Many studies in both animal and plant systems have shown that matrix attachment regions (MARs) can increase the expression of flanking transgenes. However, our previous studies revealed no effect of the chicken lysozyme MARs (chiMARs) on transgene expression in the first generation transgenic Arabidopsis thaliana plants transformed with a beta-glucuronidase gene (uidA) unless gene silencing mutants were used as genetic background for transformation. In the present study, we investigated why chiMARs do not influence transgene expression in transgenic wild-type Arabidopsis plants. We first studied the effect of chiMARs on transgene expression in the progeny of primary transformants harboring chiMAR-flanked T-DNAs. Our data indicate that chiMARs do not affect transgene expression in consecutive generations of wild-type A. thaliana plants. Next, we examined whether these observed results in A. thaliana transformants are influenced by the applied transformation method. The results from in vitro transformed A. thaliana plants are in accordance with those from in planta transformed A. thaliana plants and again reveal no influence of chiMARs on transgene expression in A. thaliana wild-type transformants. The effect of chi-MARs on transgene expression is also examined in in vitro transformed Nicotiana tabacum plants, but as for A. thaliana, the transgene expression in tobacco transformants is not altered by the presence of chi-MARs. Taken together, our results show that the applied method or the plant species used for transformation does not influence whether and how chiMARs have an effect on transgene expression. Finally, we studied the effect of MARs (tabMARs) of plant origin (tobacco) on the transgene expression in A. thaliana wild-type plants and suppressed gene silencing (sgs2) mutants. Our results clearly show that similar to chiMARs, the tobacco-derived MARs do not enhance transgene expression in a wild-type background but can be used to enhance transgene expression

  17. Capsella rubella TGA4, a bZIP transcription factor, causes delayed flowering in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Li Maofu

    2016-01-01

    Full Text Available Flowering time is usually regulated by many environmental factors and endogenous signals. TGA family members are bZIP transcription factors that bind to the octopine synthase element, which has been closely linked to defense/stress responses. Most TGA factors interact with non-expressor of PR1 (NPR1 and plant defense responses are strengthened by this interaction. TGA1and TGA4factors bind to NPR1 only in salicylic acid (SA-induced leaves, suggesting that TGA4 has another function during plant development. Here, we isolated a bZIP transcription factor gene, TGA4, from Capsella rubella. TGA4transcripts were detected in most tissues, with high expression in leaves, low expression in stems and flowering buds, and undetectable in siliques. CruTGA4was over expressed in Arabidopsis thaliana wild typeCol-0 plants. Flowering time and total leaf number in the transgenic plants showed that overexpression of CruTGA4could delay flowering in A. thaliana. Our findings suggest that TGA4 may act as flowering regulator that controls plant flowering.

  18. Natural genetic variation in selected populations of Arabidopsis thaliana is associated with ionomic differences.

    Directory of Open Access Journals (Sweden)

    Elizabeth Buescher

    Full Text Available Controlling elemental composition is critical for plant growth and development as well as the nutrition of humans who utilize plants for food. Uncovering the genetic architecture underlying mineral ion homeostasis in plants is a critical first step towards understanding the biochemical networks that regulate a plant's elemental composition (ionome. Natural accessions of Arabidopsis thaliana provide a rich source of genetic diversity that leads to phenotypic differences. We analyzed the concentrations of 17 different elements in 12 A. thaliana accessions and three recombinant inbred line (RIL populations grown in several different environments using high-throughput inductively coupled plasma- mass spectroscopy (ICP-MS. Significant differences were detected between the accessions for most elements and we identified over a hundred QTLs for elemental accumulation in the RIL populations. Altering the environment the plants were grown in had a strong effect on the correlations between different elements and the QTLs controlling elemental accumulation. All ionomic data presented is publicly available at www.ionomicshub.org.

  19. Beneficial Bacteria Isolated from Grapevine Inner Tissues Shape Arabidopsis thaliana Roots.

    Directory of Open Access Journals (Sweden)

    Enrico Baldan

    Full Text Available We investigated the potential plant growth-promoting traits of 377 culturable endophytic bacteria, isolated from Vitis vinifera cv. Glera, as good biofertilizer candidates in vineyard management. Endophyte ability in promoting plant growth was assessed in vitro by testing ammonia production, phosphate solubilization, indole-3-acetic acid (IAA and IAA-like molecule biosynthesis, siderophore and lytic enzyme secretion. Many of the isolates were able to mobilize phosphate (33%, release ammonium (39%, secrete siderophores (38% and a limited part of them synthetized IAA and IAA-like molecules (5%. Effects of each of the 377 grapevine beneficial bacteria on Arabidopsis thaliana root development were also analyzed to discern plant growth-promoting abilities (PGP of the different strains, that often exhibit more than one PGP trait. A supervised model-based clustering analysis highlighted six different classes of PGP effects on root architecture. A. thaliana DR5::GUS plantlets, inoculated with IAA-producing endophytes, resulted in altered root growth and enhanced auxin response. Overall, the results indicate that the Glera PGP endospheric culturable microbiome could contribute, by structural root changes, to obtain water and nutrients increasing plant adaptation and survival. From the complete cultivable collection, twelve promising endophytes mainly belonging to the Bacillus but also to Micrococcus and Pantoea genera, were selected for further investigations in the grapevine host plants towards future application in sustainable management of vineyards.

  20. Beneficial Bacteria Isolated from Grapevine Inner Tissues Shape Arabidopsis thaliana Roots.

    Science.gov (United States)

    Baldan, Enrico; Nigris, Sebastiano; Romualdi, Chiara; D'Alessandro, Stefano; Clocchiatti, Anna; Zottini, Michela; Stevanato, Piergiorgio; Squartini, Andrea; Baldan, Barbara

    2015-01-01

    We investigated the potential plant growth-promoting traits of 377 culturable endophytic bacteria, isolated from Vitis vinifera cv. Glera, as good biofertilizer candidates in vineyard management. Endophyte ability in promoting plant growth was assessed in vitro by testing ammonia production, phosphate solubilization, indole-3-acetic acid (IAA) and IAA-like molecule biosynthesis, siderophore and lytic enzyme secretion. Many of the isolates were able to mobilize phosphate (33%), release ammonium (39%), secrete siderophores (38%) and a limited part of them synthetized IAA and IAA-like molecules (5%). Effects of each of the 377 grapevine beneficial bacteria on Arabidopsis thaliana root development were also analyzed to discern plant growth-promoting abilities (PGP) of the different strains, that often exhibit more than one PGP trait. A supervised model-based clustering analysis highlighted six different classes of PGP effects on root architecture. A. thaliana DR5::GUS plantlets, inoculated with IAA-producing endophytes, resulted in altered root growth and enhanced auxin response. Overall, the results indicate that the Glera PGP endospheric culturable microbiome could contribute, by structural root changes, to obtain water and nutrients increasing plant adaptation and survival. From the complete cultivable collection, twelve promising endophytes mainly belonging to the Bacillus but also to Micrococcus and Pantoea genera, were selected for further investigations in the grapevine host plants towards future application in sustainable management of vineyards.

  1. Beneficial Bacteria Isolated from Grapevine Inner Tissues Shape Arabidopsis thaliana Roots

    Science.gov (United States)

    Baldan, Enrico; Nigris, Sebastiano; Romualdi, Chiara; D’Alessandro, Stefano; Clocchiatti, Anna; Zottini, Michela; Stevanato, Piergiorgio; Squartini, Andrea; Baldan, Barbara

    2015-01-01

    We investigated the potential plant growth-promoting traits of 377 culturable endophytic bacteria, isolated from Vitis vinifera cv. Glera, as good biofertilizer candidates in vineyard management. Endophyte ability in promoting plant growth was assessed in vitro by testing ammonia production, phosphate solubilization, indole-3-acetic acid (IAA) and IAA-like molecule biosynthesis, siderophore and lytic enzyme secretion. Many of the isolates were able to mobilize phosphate (33%), release ammonium (39%), secrete siderophores (38%) and a limited part of them synthetized IAA and IAA-like molecules (5%). Effects of each of the 377 grapevine beneficial bacteria on Arabidopsis thaliana root development were also analyzed to discern plant growth-promoting abilities (PGP) of the different strains, that often exhibit more than one PGP trait. A supervised model-based clustering analysis highlighted six different classes of PGP effects on root architecture. A. thaliana DR5::GUS plantlets, inoculated with IAA-producing endophytes, resulted in altered root growth and enhanced auxin response. Overall, the results indicate that the Glera PGP endospheric culturable microbiome could contribute, by structural root changes, to obtain water and nutrients increasing plant adaptation and survival. From the complete cultivable collection, twelve promising endophytes mainly belonging to the Bacillus but also to Micrococcus and Pantoea genera, were selected for further investigations in the grapevine host plants towards future application in sustainable management of vineyards. PMID:26473358

  2. The Flowering Repressor SVP Underlies a Novel Arabidopsis thaliana QTL Interacting with the Genetic Background

    Science.gov (United States)

    Méndez-Vigo, Belén; Martínez-Zapater, José M.; Alonso-Blanco, Carlos

    2013-01-01

    The timing of flowering initiation is a fundamental trait for the adaptation of annual plants to different environments. Large amounts of intraspecific quantitative variation have been described for it among natural accessions of many species, but the molecular and evolutionary mechanisms underlying this genetic variation are mainly being determined in the model plant Arabidopsis thaliana. To find novel A. thaliana flowering QTL, we developed introgression lines from the Japanese accession Fuk, which was selected based on the substantial transgression observed in an F2 population with the reference strain Ler. Analysis of an early flowering line carrying a single Fuk introgression identified Flowering Arabidopsis QTL1 (FAQ1). We fine-mapped FAQ1 in an 11 kb genomic region containing the MADS transcription factor gene SHORT VEGETATIVE PHASE (SVP). Complementation of the early flowering phenotype of FAQ1-Fuk with a SVP-Ler transgen demonstrated that FAQ1 is SVP. We further proved by directed mutagenesis and transgenesis that a single amino acid substitution in SVP causes the loss-of-function and early flowering of Fuk allele. Analysis of a worldwide collection of accessions detected FAQ1/SVP-Fuk allele only in Asia, with the highest frequency appearing in Japan, where we could also detect a potential ancestral genotype of FAQ1/SVP-Fuk. In addition, we evaluated allelic and epistatic interactions of SVP natural alleles by analysing more than one hundred transgenic lines carrying Ler or Fuk SVP alleles in five genetic backgrounds. Quantitative analyses of these lines showed that FAQ1/SVP effects vary from large to small depending on the genetic background. These results support that the flowering repressor SVP has been recently selected in A. thaliana as a target for early flowering, and evidence the relevance of genetic interactions for the intraspecific evolution of FAQ1/SVP and flowering time. PMID:23382706

  3. Transgenic Arabidopsis thaliana containing increased levels of ATP and sucrose is more susceptible to Pseudomonas syringae

    Science.gov (United States)

    Zhang, Renshan; Qi, Hua; Sun, Yuzhe; Xiao, Shi

    2017-01-01

    Disease resistance exerts a fitness cost on plants, presumably due to the extra consumption of energy and carbon. In this study, we examined whether transgenic Arabidopsis thaliana with increased levels of ATP and sucrose is more resistant or susceptible to pathogen infection. Lines of A. thaliana over-expressing purple acid phosphatase 2 (AtPAP2) (OE lines) contain increased levels of ATP and sucrose, with improved growth rate and seed production. Compared to wild type (WT) and pap2 lines, the OE lines were more susceptible to several Pseudomonas syringae pv. tomato (Pst) strains carrying AvrRpm1, AvrRpt2 AvrRps4, AvrPtoB, HrcC and WT strain DC3000. The increased susceptibility of the OE lines to Pst strains cannot solely be attributed to the suppressed expression of R-genes but must also be attributed to the suppression of downstream signaling components, such as MOS2, EDS1 and EDS5. Before infection, the levels of salicylic acid (SA) and jasmonic acid (JA) precursor OPDA were similar in the leaves of OE, pap2 and WT plants, whereas the levels of JA and its derivative JA-Ile were significantly lower in the leaves of OE lines and higher in the pap2 line. The expression of JA marker defense gene PDF1.2 was up-regulated in the OE lines compared to the WT prior to Pst DC3000 infection, but its expression was lower in the OE lines after infection. In summary, high fitness Arabidopsis thaliana exhibited altered JA metabolism and broad suppression of R-genes and downstream genes as well as a higher susceptibility to Pst infections. PMID:28152090

  4. The flowering repressor SVP underlies a novel Arabidopsis thaliana QTL interacting with the genetic background.

    Directory of Open Access Journals (Sweden)

    Belén Méndez-Vigo

    Full Text Available The timing of flowering initiation is a fundamental trait for the adaptation of annual plants to different environments. Large amounts of intraspecific quantitative variation have been described for it among natural accessions of many species, but the molecular and evolutionary mechanisms underlying this genetic variation are mainly being determined in the model plant Arabidopsis thaliana. To find novel A. thaliana flowering QTL, we developed introgression lines from the Japanese accession Fuk, which was selected based on the substantial transgression observed in an F(2 population with the reference strain Ler. Analysis of an early flowering line carrying a single Fuk introgression identified Flowering Arabidopsis QTL1 (FAQ1. We fine-mapped FAQ1 in an 11 kb genomic region containing the MADS transcription factor gene SHORT VEGETATIVE PHASE (SVP. Complementation of the early flowering phenotype of FAQ1-Fuk with a SVP-Ler transgen demonstrated that FAQ1 is SVP. We further proved by directed mutagenesis and transgenesis that a single amino acid substitution in SVP causes the loss-of-function and early flowering of Fuk allele. Analysis of a worldwide collection of accessions detected FAQ1/SVP-Fuk allele only in Asia, with the highest frequency appearing in Japan, where we could also detect a potential ancestral genotype of FAQ1/SVP-Fuk. In addition, we evaluated allelic and epistatic interactions of SVP natural alleles by analysing more than one hundred transgenic lines carrying Ler or Fuk SVP alleles in five genetic backgrounds. Quantitative analyses of these lines showed that FAQ1/SVP effects vary from large to small depending on the genetic background. These results support that the flowering repressor SVP has been recently selected in A. thaliana as a target for early flowering, and evidence the relevance of genetic interactions for the intraspecific evolution of FAQ1/SVP and flowering time.

  5. Regulation of the S-locus receptor kinase and self-incompatibility in Arabidopsis thaliana.

    Science.gov (United States)

    Strickler, Susan R; Tantikanjana, Titima; Nasrallah, June B

    2013-02-01

    Intraspecific mate selectivity often is enforced by self-incompatibility (SI), a barrier to self-pollination that inhibits productive pollen-pistil interactions. In the Brassicaceae, SI specificity is determined by two highly-polymorphic proteins: the stigmatic S-locus receptor kinase (SRK) and its pollen coat-localized ligand, the S-locus cysteine-rich protein (SCR). Arabidopsis thaliana is self fertile, but several of its accessions can be made to express SI, albeit to various degrees, by transformation with functional SRK-SCR gene pairs isolated from its close self-incompatible relative, Arabidopsis lyrata. Here, we use a newly identified induced mutation that suppresses the SI phenotype in stigmas of SRK-SCR transformants of the Col-0 accession to investigate the regulation of SI and the SRK transgene. This mutation disrupts NRPD1a, a gene that encodes a plant-specific nuclear RNA polymerase required for genomic methylation and production of some types of silencing RNAs. We show that NRPD1a, along with the RNA-dependent RNA polymerase RDR2, is required for SI in some A. thaliana accessions. We also show that Col-0 nrpd1a mutants exhibit decreased accumulation of SRK transcripts in stigmas, which is not, however, responsible for loss of SI in these plants. Together, our analysis of the nrpd1a mutation and of SRK promoter activity in various accessions reveals that the SRK transgene is subject to several levels of regulation, which vary substantially by tissue type and by accession. This study thus helps explain the well-documented differences in expression of SI exhibited by SRK-SCR transformants of different A. thaliana accessions.

  6. An Efficient Visual Screen for CRISPR/Cas9 Activity in Arabidopsis thaliana

    Science.gov (United States)

    Hahn, Florian; Mantegazza, Otho; Greiner, André; Hegemann, Peter; Eisenhut, Marion; Weber, Andreas P. M.

    2017-01-01

    The CRISPR/Cas9 system enables precision editing of the genome of the model plant Arabidopsis thaliana and likely of any other organism. Tools and methods for further developing and optimizing this widespread and versatile system in Arabidopsis would hence be welcomed. Here, we designed a generic vector system that can be used to clone any sgRNA sequence in a plant T-DNA vector containing an ubiquitously expressed Cas9 gene. With this vector, we explored two alternative marker systems for tracking Cas9-mediated gene-editing in vivo: BIALAPHOS RESISTANCE (BAR) and GLABROUS1 (GL1). BAR confers resistance to glufosinate and is widely used as a positive selection marker; GL1 is required for the formation of trichomes. Reversion of a frameshift null BAR allele to a functional one by Cas9-mediated gene editing yielded a higher than expected number of plants that are resistant to glufosinate. Surprisingly, many of those plants did not display reversion of the BAR gene through the germline. We hypothesize that few BAR revertant cells in a highly chimeric plant likely provide system-wide resistance to glufosinate and thus we suggest that BAR is not suitable as marker for tracking Cas9-mediated gene-editing. Targeting the GL1 gene for disruption with Cas9 provided clearly visible phenotypes of partially and completely glabrous plants. 50% of the analyzed T1 plants produced descendants with a chimeric phenotype and we could recover fully homozygous plants in the T3 generation with high efficiency. We propose that targeting of GL1 is suitable for assessing and optimizing Cas9-mediated gene-editing in Arabidopsis. PMID:28174584

  7. Effector-Triggered Immune Response in Arabidopsis thaliana Is a Quantitative Trait

    Science.gov (United States)

    Iakovidis, Michail; Teixeira, Paulo J. P. L.; Exposito-Alonso, Moises; Cowper, Matthew G.; Law, Theresa F.; Liu, Qingli; Vu, Minh Chau; Dang, Troy Minh; Corwin, Jason A.; Weigel, Detlef; Dangl, Jeffery L.; Grant, Sarah R.

    2016-01-01

    We identified loci responsible for natural variation in Arabidopsis thaliana (Arabidopsis) responses to a bacterial pathogen virulence factor, HopAM1. HopAM1 is a type III effector protein secreted by the virulent Pseudomonas syringae strain Pto DC3000. Delivery of HopAM1 from disarmed Pseudomonas strains leads to local cell death, meristem chlorosis, or both, with varying intensities in different Arabidopsis accessions. These phenotypes are not associated with differences in bacterial growth restriction. We treated the two phenotypes as quantitative traits to identify host loci controlling responses to HopAM1. Genome-wide association (GWA) of 64 Arabidopsis accessions identified independent variants highly correlated with response to each phenotype. Quantitative trait locus (QTL) mapping in a recombinant inbred population between Bur-0 and Col-0 accessions revealed genetic linkage to regions distinct from the top GWA hits. Two major QTL associated with HopAM1-induced cell death were also associated with HopAM1-induced chlorosis. HopAM1-induced changes in Arabidopsis gene expression showed that rapid HopAM1-dependent cell death in Bur-0 is correlated with effector-triggered immune responses. Studies of the effect of mutations in known plant immune system genes showed, surprisingly, that both cell death and chlorosis phenotypes are enhanced by loss of EDS1, a regulatory hub in the plant immune-signaling network. Our results reveal complex genetic architecture for response to this particular type III virulence effector, in contrast to the typical monogenic control of cell death and disease resistance triggered by most type III effectors. PMID:27412712

  8. Effector-Triggered Immune Response in Arabidopsis thaliana Is a Quantitative Trait.

    Science.gov (United States)

    Iakovidis, Michail; Teixeira, Paulo J P L; Exposito-Alonso, Moises; Cowper, Matthew G; Law, Theresa F; Liu, Qingli; Vu, Minh Chau; Dang, Troy Minh; Corwin, Jason A; Weigel, Detlef; Dangl, Jeffery L; Grant, Sarah R

    2016-09-01

    We identified loci responsible for natural variation in Arabidopsis thaliana (Arabidopsis) responses to a bacterial pathogen virulence factor, HopAM1. HopAM1 is a type III effector protein secreted by the virulent Pseudomonas syringae strain Pto DC3000. Delivery of HopAM1 from disarmed Pseudomonas strains leads to local cell death, meristem chlorosis, or both, with varying intensities in different Arabidopsis accessions. These phenotypes are not associated with differences in bacterial growth restriction. We treated the two phenotypes as quantitative traits to identify host loci controlling responses to HopAM1. Genome-wide association (GWA) of 64 Arabidopsis accessions identified independent variants highly correlated with response to each phenotype. Quantitative trait locus (QTL) mapping in a recombinant inbred population between Bur-0 and Col-0 accessions revealed genetic linkage to regions distinct from the top GWA hits. Two major QTL associated with HopAM1-induced cell death were also associated with HopAM1-induced chlorosis. HopAM1-induced changes in Arabidopsis gene expression showed that rapid HopAM1-dependent cell death in Bur-0 is correlated with effector-triggered immune responses. Studies of the effect of mutations in known plant immune system genes showed, surprisingly, that both cell death and chlorosis phenotypes are enhanced by loss of EDS1, a regulatory hub in the plant immune-signaling network. Our results reveal complex genetic architecture for response to this particular type III virulence effector, in contrast to the typical monogenic control of cell death and disease resistance triggered by most type III effectors.

  9. Similar Pathogen Targets in Arabidopsis thaliana and Homo sapiens Protein Networks

    Science.gov (United States)

    2012-09-21

    transduction components between organelle such as the nucleus and mitochondria as the cell strives to maintain homeostasis. Many of these communication... Similar Pathogen Targets in Arabidopsis thaliana and Homo sapiens Protein Networks Paulo Shakarian1*, J. Kenneth Wickiser2 1 Paulo Shakarian...pathogens on host protein networks for humans and Arabidopsis - noting striking similarities . Specifically, we preform k-shell decomposition analysis on

  10. Affinity Purification of O-Acetylserine(thiollyase from Chlorella sorokiniana by Recombinant Proteins from Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Giovanna Salbitani

    2014-08-01

    Full Text Available In the unicellular green alga Chlorella sorokiniana (211/8 k, the protein O-acetylserine(thiollyase (OASTL, representing the key-enzyme in the biosynthetic cysteine pathway, was isolated and purified to apparent homogeneity. The purification was carried out in cells grown in the presence of all nutrients or in sulphate (S deprived cells. After 24 h of S-starvation, a 17-fold increase in the specific activity of OASTL was measured. In order to enable the identification of OASTL proteins from non-model organisms such as C. sorokiniana, the recombinant his-tagged SAT5 protein from Arabidopsis thaliana was immobilized by metal chelate chromatography. OASTL proteins from C. sorokiniana were affinity purified in one step and activities were enhanced 29- and 41-fold, from S-sufficient and S-starved (24 h cells, respectively. The successful application of SAT/OASTL interaction for purification confirms for the first time the existence of the cysteine synthase complexes in microalgae. The purified proteins have apparent molecular masses between 32–34 kDa and are thus slightly larger compared to those found in Arabidopsis thaliana and other vascular plants. The enhanced OASTL activity in S-starved cells can be attributed to increased amounts of plastidic and the emergence of cytosolic OASTL isoforms. The results provide proof-of-concept for the biochemical analysis of the cysteine synthase complex in diverse microalgal species.

  11. An ANN-GA model based promoter prediction in Arabidopsis thaliana using tilling microarray data

    Science.gov (United States)

    Mishra, Hrishikesh; Singh, Nitya; Misra, Krishna; Lahiri, Tapobrata

    2011-01-01

    Identification of promoter region is an important part of gene annotation. Identification of promoters in eukaryotes is important as promoters modulate various metabolic functions and cellular stress responses. In this work, a novel approach utilizing intensity values of tilling microarray data for a model eukaryotic plant Arabidopsis thaliana, was used to specify promoter region from non-promoter region. A feed-forward back propagation neural network model supported by genetic algorithm was employed to predict the class of data with a window size of 41. A dataset comprising of 2992 data vectors representing both promoter and non-promoter regions, chosen randomly from probe intensity vectors for whole genome of Arabidopsis thaliana generated through tilling microarray technique was used. The classifier model shows prediction accuracy of 69.73% and 65.36% on training and validation sets, respectively. Further, a concept of distance based class membership was used to validate reliability of classifier, which showed promising results. The study shows the usability of micro-array probe intensities to predict the promoter regions in eukaryotic genomes. PMID:21887014

  12. Arabidopsis thaliana as a tool to identify traits involved in Verticillium dahliae biocontrol by the olive root endophyte Pseudomonas fluorescens PICF7

    Science.gov (United States)

    Maldonado-González, M. Mercedes; Bakker, Peter A. H. M.; Prieto, Pilar; Mercado-Blanco, Jesús

    2015-01-01

    The effective management of Verticillium wilts (VW), diseases affecting many crops and caused by some species of the soil-borne fungus Verticillium, is problematic. The use of microbial antagonists to control these pathologies fits modern sustainable agriculture criteria. Pseudomonas fluorescens PICF7 is an endophytic bacterium isolated from olive roots with demonstrated ability to control VW of olive caused by the highly virulent, defoliating (D) pathotype of Verticillium dahliae Kleb. However, the study of the PICF7-V. dahliae-olive tripartite interaction poses difficulties because of the inherent characteristics of woody, long-living plants. To overcome these problems we explored the use of the model plant Arabidopsis thaliana. Results obtained in this study showed that: (i) olive D and non-defoliating V. dahliae pathotypes produce differential disease severity in A. thaliana plants; (ii) strain PICF7 is able to colonize and persist in the A. thaliana rhizosphere but is not endophytic in Arabidopsis; and (iii) strain PICF7 controls VW in Arabidopsis. Additionally, as previously observed in olive, neither swimming motility nor siderophore production by PICF7 are required for VW control in A. thaliana, whilst cysteine auxotrophy decreased the effectiveness of PICF7. Moreover, when applied to the roots PICF7 controlled Botrytis cinerea infection in the leaves of Arabidopsis, suggesting that this strain is able to induce systemic resistance. A. thaliana is therefore a suitable alternative to olive bioassays to unravel biocontrol traits involved in biological control of V. dahliae by P. fluorescens PICF7. PMID:25904904

  13. Gravity-regulated gene expression in Arabidopsis thaliana

    Science.gov (United States)

    Sederoff, Heike; Brown, Christopher S.; Heber, Steffen; Kajla, Jyoti D.; Kumar, Sandeep; Lomax, Terri L.; Wheeler, Benjamin; Yalamanchili, Roopa

    Plant growth and development is regulated by changes in environmental signals. Plants sense environmental changes and respond to them by modifying gene expression programs to ad-just cell growth, differentiation, and metabolism. Functional expression of genes comprises many different processes including transcription, translation, post-transcriptional and post-translational modifications, as well as the degradation of RNA and proteins. Recently, it was discovered that small RNAs (sRNA, 18-24 nucleotides long), which are heritable and systemic, are key elements in regulating gene expression in response to biotic and abiotic changes. Sev-eral different classes of sRNAs have been identified that are part of a non-cell autonomous and phloem-mobile network of regulators affecting transcript stability, translational kinetics, and DNA methylation patterns responsible for heritable transcriptional silencing (epigenetics). Our research has focused on gene expression changes in response to gravistimulation of Arabidopsis roots. Using high-throughput technologies including microarrays and 454 sequencing, we iden-tified rapid changes in transcript abundance of genes as well as differential expression of small RNA in Arabidopsis root apices after minutes of reorientation. Some of the differentially regu-lated transcripts are encoded by genes that are important for the bending response. Functional mutants of those genes respond faster to reorientation than the respective wild type plants, indicating that these proteins are repressors of differential cell elongation. We compared the gravity responsive sRNAs to the changes in transcript abundances of their putative targets and identified several potential miRNA: target pairs. Currently, we are using mutant and transgenic Arabidopsis plants to characterize the function of those miRNAs and their putative targets in gravitropic and phototropic responses in Arabidopsis.

  14. Large genetic screens for gynogenesis and androgenesis haploid inducers in Arabidopsis thaliana failed to identify mutants

    Directory of Open Access Journals (Sweden)

    Virginie ePortemer

    2015-03-01

    Full Text Available Gynogenesis is a process in which the embryo genome originates exclusively from female origin, following embryogenesis stimulation by a male gamete. In contrast, androgenesis is the development of embryos that contain only the male nuclear genetic background. Both phenomena are of great interest in plant breeding as haploidisation is an efficient tool to reduce the length of breeding schemes to create varieties. Although few inducer lines have been described, the genetic control of these phenomena is poorly understood. We developed genetic screens to identify mutations that would induce gynogenesis or androgenesis in Arabidopsis thaliana. The ability of mutant pollen to induce either gynogenesis or androgenesis was tested by crossing mutagenized plants as males. Seedlings from these crosses were screened with recessive phenotypic markers, one genetically controlled by the female genome and another by the male genome. Positive and negative controls confirmed the unambiguous detection of both gynogenesis and androgenesis events. This strategy was applied to 1,666 EMS-mutagenised lines and 47 distant Arabidopsis strains. While an internal control suggested that the mutagenesis reached saturation, no gynogenesis or androgenesis inducer was found. However, spontaneous gynogenesis was observed at a frequency of 1/10,800. Altogether, these results suggest that no simple EMS-induced mutation in the male genome is able to induce gynogenesis or androgenesis in Arabidopsis.

  15. A comparative study of salt tolerance parameters in 11 wild relatives of Arabidopsis thaliana

    KAUST Repository

    Orsini, Francesco

    2010-07-01

    Salinity is an abiotic stress that limits both yield and the expansion of agricultural crops to new areas. In the last 20 years our basic understanding of the mechanisms underlying plant tolerance and adaptation to saline environments has greatly improved owing to active development of advanced tools in molecular, genomics, and bioinformatics analyses. However, the full potential of investigative power has not been fully exploited, because the use of halophytes as model systems in plant salt tolerance research is largely neglected. The recent introduction of halophytic Arabidopsis-Relative Model Species (ARMS) has begun to compare and relate several unique genetic resources to the well-developed Arabidopsis model. In a search for candidates to begin to understand, through genetic analyses, the biological bases of salt tolerance, 11 wild relatives of Arabidopsis thaliana were compared: Barbarea verna, Capsella bursa-pastoris, Hirschfeldia incana, Lepidium densiflorum, Malcolmia triloba, Lepidium virginicum, Descurainia pinnata, Sisymbrium officinale, Thellungiella parvula, Thellungiella salsuginea (previously T. halophila), and Thlaspi arvense. Among these species, highly salt-tolerant (L. densiflorum and L. virginicum) and moderately salt-tolerant (M. triloba and H. incana) species were identified. Only T. parvula revealed a true halophytic habitus, comparable to the better studied Thellungiella salsuginea. Major differences in growth, water transport properties, and ion accumulation are observed and discussed to describe the distinctive traits and physiological responses that can now be studied genetically in salt stress research. 2010 The Author.

  16. Genome wide analysis of stress responsive WRKY transcription factors in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Shaiq Sultan

    2016-04-01

    Full Text Available WRKY transcription factors are a class of DNA-binding proteins that bind with a specific sequence C/TTGACT/C known as W-Box found in promoters of genes which are regulated by these WRKYs. From previous studies, 43 different stress responsive WRKY transcription factors in Arabidopsis thaliana, identified and then categorized in three groups viz., abiotic, biotic and both of these stresses. A comprehensive genome wide analysis including chromosomal localization, gene structure analysis, multiple sequence alignment, phylogenetic analysis and promoter analysis of these WRKY genes was carried out in this study to determine the functional homology in Arabidopsis. This analysis led to the classification of these WRKY family members into 3 major groups and subgroups and showed evolutionary relationship among these groups on the base of their functional WRKY domain, chromosomal localization and intron/exon structure. The proposed groups of these stress responsive WRKY genes and annotation based on their position on chromosomes can also be explored to determine their functional homology in other plant species in relation to different stresses. The result of the present study provides indispensable genomic information for the stress responsive WRKY transcription factors in Arabidopsis and will pave the way to explain the precise role of various AtWRKYs in plant growth and development under stressed conditions.

  17. Phenotypical and molecular responses of Arabidopsis thaliana roots as a result of inoculation with the auxin-producing bacterium Azospirillum brasilense.

    Science.gov (United States)

    Spaepen, Stijn; Bossuyt, Stijn; Engelen, Kristof; Marchal, Kathleen; Vanderleyden, Jos

    2014-02-01

    The auxin-producing bacterium Azospirillum brasilense Sp245 can promote the growth of several plant species. The model plant Arabidopsis thaliana was chosen as host plant to gain an insight into the molecular mechanisms that govern this interaction. The determination of differential gene expression in Arabidopsis roots after inoculation with either A. brasilense wild-type or an auxin biosynthesis mutant was achieved by microarray analysis. Arabidopsis thaliana inoculation with A. brasilense wild-type increases the number of lateral roots and root hairs, and elevates the internal auxin concentration in the plant. The A. thaliana root transcriptome undergoes extensive changes on A. brasilense inoculation, and the effects are more pronounced at later time points. The wild-type bacterial strain induces changes in hormone- and defense-related genes, as well as in plant cell wall-related genes. The A. brasilense mutant, however, does not elicit these transcriptional changes to the same extent. There are qualitative and quantitative differences between A. thaliana responses to the wild-type A. brasilense strain and the auxin biosynthesis mutant strain, based on both phenotypic and transcriptomic data. This illustrates the major role played by auxin in the Azospirillum-Arabidopsis interaction, and possibly also in other bacterium-plant interactions.

  18. A novel high efficiency, low maintenance, hydroponic system for synchronous growth and flowering of Arabidopsis thaliana

    Science.gov (United States)

    Tocquin, Pierre; Corbesier, Laurent; Havelange, Andrée; Pieltain, Alexandra; Kurtem, Emile; Bernier, Georges; Périlleux, Claire

    2003-01-01

    Background Arabidopsis thaliana is now the model organism for genetic and molecular plant studies, but growing conditions may still impair the significance and reproducibility of the experimental strategies developed. Besides the use of phytotronic cabinets, controlling plant nutrition may be critical and could be achieved in hydroponics. The availability of such a system would also greatly facilitate studies dealing with root development. However, because of its small size and rosette growth habit, Arabidopsis is hardly grown in standard hydroponic devices and the systems described in the last years are still difficult to transpose at a large scale. Our aim was to design and optimize an up-scalable device that would be adaptable to any experimental conditions. Results An hydroponic system was designed for Arabidopsis, which is based on two units: a seed-holder and a 1-L tank with its cover. The original agar-containing seed-holder allows the plants to grow from sowing to seed set, without transplanting step and with minimal waste. The optimum nitrate supply was determined for vegetative growth, and the flowering response to photoperiod and vernalization was characterized to show the feasibility and reproducibility of experiments extending over the whole life cycle. How this equipment allowed to overcome experimental problems is illustrated by the analysis of developmental effects of nitrate reductase deficiency in nia1nia2 mutants. Conclusion The hydroponic device described in this paper allows to drive small and large scale cultures of homogeneously growing Arabidopsis plants. Its major advantages are its flexibility, easy handling, fast maintenance and low cost. It should be suitable for many experimental purposes. PMID:12556248

  19. The Physiological and Molecular Responses of Arabidopsis thaliana to the Stress of Oxalic Acid

    Institute of Scientific and Technical Information of China (English)

    CHEN Xiao-ting; LIN Jie; SHAO Xue-feng; OU Xiao-ming; WANG Zong-hua; LU Guo-dong

    2009-01-01

    Many fungal phytopathogens can secrete oxalic acid (OA), which is the crucial pathogenic determinant and plays important roles in pathogenicity and virulence of pathogen during infection process. However, how plants respond to OA stress still needs further characterization. In this study, we observed the physiological and molecular responses of Arabidopsis thaliana to OA stress. The leaves of 6-wk-old A. thaliana were sprayed with OA and distilled water respectively, and 0, 2, 4, 8, 12, and 24 h later, the leaves were collected and the contents of MDA, H2O2, and GSH, and the activities of CAT, SOD, and POD were determined and the expressions of PR1 and PDF1.2 were also studied. Under the stress of 30 mmol L-1 OA, SOD activity was first enhanced to reduce the accumulation of O2-. But immediately, POD, CAT, and GSH all decreased extremely resulting in the accumulation of H2O2, and the MDA content increased 24 h later. GSH activity was enhanced significantly at 24 h after OA used. However, H2O2 wasn't eliminated at the same time, suggesting that the activity inhibitions of POD and CAT might be the reasons that caused Arabidopsis cells' impairment under OA stress. RT-PCR results indicated that PDF1.2, a marker gene of the JA/ET signaling was significantly induced; PR1, an indicator gene in SA signaling, was slighlty induced from 8 to 12 h after OA stress. In conclusion, Arabidopsis may recruit metabolism of reactive oxygen, both JA/ET and SA signaling pathways to respond to OA stress. These results will facilitate our further understanding the mechanisms of plant response to OA and OA-dependent fungal infection.

  20. Uranium perturbs signaling and iron uptake response in Arabidopsis thaliana roots.

    Science.gov (United States)

    Doustaly, Fany; Combes, Florence; Fiévet, Julie B; Berthet, Serge; Hugouvieux, Véronique; Bastien, Olivier; Aranjuelo, Iker; Leonhardt, Nathalie; Rivasseau, Corinne; Carrière, Marie; Vavasseur, Alain; Renou, Jean-Pierre; Vandenbrouck, Yves; Bourguignon, Jacques

    2014-04-01

    Uranium is a natural element which is mainly redistributed in the environment due to human activity, including accidents and spillages. Plants may be useful in cleaning up after incidents, although little is yet known about the relationship between metal speciation and plant response. Here, J-Chess modeling was used to predict U speciation and exposure conditions affecting U bioavailability for plants. The model was confirmed by exposing Arabidopsis thaliana plants to U under hydroponic conditions. The early root response was characterized using complete Arabidopsis transcriptome microarrays (CATMA). Expression of 111 genes was modified at the three timepoints studied. The associated biological processes were further examined by real-time quantitative RT-PCR. Annotation revealed that oxidative stress, cell wall and hormone biosynthesis, and signaling pathways (including phosphate signaling) were affected by U exposure. The main actors in iron uptake and signaling (IRT1, FRO2, AHA2, AHA7 and FIT1) were strongly down-regulated upon exposure to uranyl. A network calculated using IRT1, FRO2 and FIT1 as bait revealed a set of genes whose expression levels change under U stress. Hypotheses are presented to explain how U perturbs the iron uptake and signaling response. These results give preliminary insights into the pathways affected by uranyl uptake, which will be of interest for engineering plants to help clean areas contaminated with U.

  1. Ubiquitin-related modifiers of Arabidopsis thaliana influence root development.

    Directory of Open Access Journals (Sweden)

    Florian John

    Full Text Available Ubiquitins are small peptides that allow for posttranslational modification of proteins. Ubiquitin-related modifier (URM proteins belong to the class of ubiquitin-like proteins. A primary function of URM proteins has been shown to be the sulfur transfer reaction leading to thiolation of tRNAs, a process that is important for accurate and effective protein translation. Recent analyses revealed that the Arabidopsis genome codes for two URM proteins, URM11 and URM12, which both are active in the tRNA thiolation process. Here, we show that URM11 and URM12 have overlapping expression patterns and are required for tRNA thiolation. The characterization of urm11 and urm12 mutants reveals that the lack of tRNA thiolation induces changes in general root architecture by influencing the rate of lateral root formation. In addition, they synergistically influence root hair cell growth. During the sulfur transfer reaction, URM proteins of different organisms interact with a thiouridylase, a protein-protein interaction that also takes place in Arabidopsis, since URM11 and URM12 interact with the Arabidopsis thiouridylase ROL5. Hence, the sulfur transfer reaction is conserved between distantly related species such as yeast, humans, and plants, and in Arabidopsis has an impact on root development.

  2. Long noncoding RNAs responsive to Fusarium oxysporum infection in Arabidopsis thaliana.

    Science.gov (United States)

    Zhu, Qian-Hao; Stephen, Stuart; Taylor, Jennifer; Helliwell, Chris A; Wang, Ming-Bo

    2014-01-01

    Short noncoding RNAs have been demonstrated to play important roles in regulation of gene expression and stress responses, but the repertoire and functions of long noncoding RNAs (lncRNAs) remain largely unexplored, particularly in plants. To explore the role of lncRNAs in disease resistance, we used a strand-specific RNA-sequencing approach to identify lncRNAs responsive to Fusarium oxysporum infection in Arabidopsis thaliana. Antisense transcription was found in c. 20% of the annotated A. thaliana genes. Several noncoding natural antisense transcripts responsive to F. oxysporum infection were found in genes implicated in disease defense. While the majority of the novel transcriptionally active regions (TARs) were adjacent to annotated genes and could be an extension of the annotated transcripts, 159 novel intergenic TARs, including 20 F. oxysporum-responsive lncTARs, were identified. Ten F. oxysporum-induced lncTARs were functionally characterized using T-DNA insertion or RNA-interference knockdown lines, and five were demonstrated to be related to disease development. Promoter analysis suggests that some of the F. oxysporum-induced lncTARs are direct targets of transcription factor(s) responsive to pathogen attack. Our results demonstrated that strand-specific RNA sequencing is a powerful tool for uncovering hidden levels of transcriptome and that IncRNAs are important components of the antifungal networks in A. thaliana. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  3. Phytotoxicity of chiral herbicide bromacil: Enantioselectivity of photosynthesis in Arabidopsis thaliana.

    Science.gov (United States)

    Chen, Zunwei; Zou, Yuqin; Wang, Jia; Li, Meichao; Wen, Yuezhong

    2016-04-01

    With the wide application of chiral herbicides and the frequent detection of photosystem II (PSII) herbicides, it is of great importance to assess the direct effects of PSII herbicides on photosynthesis in an enantiomeric level. In the present study, the enantioselective phytotoxicity of bromacil (BRO), typical photosynthesis inhibition herbicide, on Arabidopsis thaliana was investigated. The results showed that S-BRO exhibited a greater inhibition of electron transmission in photosystem I (PSI) of A. thaliana than R-BRO by inhibiting the transcription of fnr 1. S-BRO also changed the chlorophyll fluorescence parameters Y (II), Y (NO), and Y (NPQ) to a greater extent than R-Bro. Transcription of genes psbO2, Lhcb3 and Lhcb6 was down-regulated in an enantioselective rhythm and S-BRO caused more serious influence, indicating that S-BRO did worse damage to the photosystem II (PSII) of A. thaliana than R-BRO. This study suggested that S-BRO disturbed the photosynthesis of plants to a larger extent than R-BRO and provided a new sight to evaluate the phytotoxicity of chiral herbicides.

  4. Glutamate dehydrogenase isoenzyme 3 (GDH3) of Arabidopsis thaliana is regulated by a combined effect of nitrogen and cytokinin.

    Science.gov (United States)

    Marchi, Laura; Degola, Francesca; Polverini, Eugenia; Tercé-Laforgue, Thérèse; Dubois, Frédéric; Hirel, Bertrand; Restivo, Francesco Maria

    2013-12-01

    In higher plants, NAD(H)-glutamate dehydrogenase (GDH; EC 1.4.1.2) is an abundant enzyme that exists in different isoenzymic forms. In Arabidopsis thaliana, three genes (Gdh1, Gdh2 and Gdh3) encode three different GDH subunits (β, α and γ) that randomly associate to form a complex array of homo- and heterohexamers. The modification of the GDH isoenzyme pattern and its regulation was studied during the development of A. thaliana in the gdh1, gdh2 single mutants and the gdh1-2 double mutant, with particular emphasis on GDH3. Investigations showed that the GDH3 isoenzyme could not be detected in closely related Arabidopsis species. The induction and regulation of GDH3 activity in the leaves and roots was investigated following nitrogen deprivation in the presence or absence of sucrose or kinetin. These experiments indicate that GDH3 is likely to play an important role during senescence and nutrient remobilization.

  5. Metabolic Profiling of Intact Arabidopsis thaliana Leaves during Circadian Cycle Using 1H High Resolution Magic Angle Spinning NMR

    Science.gov (United States)

    van Schadewijk, R.; de Groot, H. J. M.; Alia, A.

    2016-01-01

    Arabidopsis thaliana is the most widely used model organism for research in plant biology. While significant advances in understanding plant growth and development have been made by focusing on the molecular genetics of Arabidopsis, extracting and understanding the functional framework of metabolism is challenging, both from a technical perspective due to losses and modification during extraction of metabolites from the leaves, and from the biological perspective, due to random variation obscuring how well the function is performed. The purpose of this work is to establish the in vivo metabolic profile directly from the Arabidopsis thaliana leaves without metabolite extraction, to reduce the complexity of the results by multivariate analysis, and to unravel the mitigation of cellular complexity by predominant functional periodicity. To achieve this, we use the circadian cycle that strongly influences metabolic and physiological processes and exerts control over the photosynthetic machinery. High resolution-magic angle spinning nuclear magnetic resonance (HR-MAS NMR) was applied to obtain the metabolic profile directly from intact Arabidopsis leaves. Combining one- and two-dimensional 1H HR-MAS NMR allowed the identification of several metabolites including sugars and amino acids in intact leaves. Multivariate analysis on HR-MAS NMR spectra of leaves throughout the circadian cycle revealed modules of primary metabolites with significant and consistent variations of their molecular components at different time points of the circadian cycle. Since robust photosynthetic performance in plants relies on the functional periodicity of the circadian rhythm, our results show that HR-MAS NMR promises to be an important non-invasive method that can be used for metabolomics of the Arabidopsis thaliana mutants with altered physiology and photosynthetic efficiency. PMID:27662620

  6. Metabolic Profiling of Intact Arabidopsis thaliana Leaves during Circadian Cycle Using 1H High Resolution Magic Angle Spinning NMR.

    Science.gov (United States)

    Augustijn, D; Roy, U; van Schadewijk, R; de Groot, H J M; Alia, A

    Arabidopsis thaliana is the most widely used model organism for research in plant biology. While significant advances in understanding plant growth and development have been made by focusing on the molecular genetics of Arabidopsis, extracting and understanding the functional framework of metabolism is challenging, both from a technical perspective due to losses and modification during extraction of metabolites from the leaves, and from the biological perspective, due to random variation obscuring how well the function is performed. The purpose of this work is to establish the in vivo metabolic profile directly from the Arabidopsis thaliana leaves without metabolite extraction, to reduce the complexity of the results by multivariate analysis, and to unravel the mitigation of cellular complexity by predominant functional periodicity. To achieve this, we use the circadian cycle that strongly influences metabolic and physiological processes and exerts control over the photosynthetic machinery. High resolution-magic angle spinning nuclear magnetic resonance (HR-MAS NMR) was applied to obtain the metabolic profile directly from intact Arabidopsis leaves. Combining one- and two-dimensional 1H HR-MAS NMR allowed the identification of several metabolites including sugars and amino acids in intact leaves. Multivariate analysis on HR-MAS NMR spectra of leaves throughout the circadian cycle revealed modules of primary metabolites with significant and consistent variations of their molecular components at different time points of the circadian cycle. Since robust photosynthetic performance in plants relies on the functional periodicity of the circadian rhythm, our results show that HR-MAS NMR promises to be an important non-invasive method that can be used for metabolomics of the Arabidopsis thaliana mutants with altered physiology and photosynthetic efficiency.

  7. Gene introduction into the mitochondria of Arabidopsis thaliana via peptide-based carriers.

    Science.gov (United States)

    Chuah, Jo-Ann; Yoshizumi, Takeshi; Kodama, Yutaka; Numata, Keiji

    2015-01-13

    Available methods in plant genetic transformation are nuclear and plastid transformations because similar procedures have not yet been established for the mitochondria. The double membrane and small size of the organelle, in addition to its large population in cells, are major obstacles in mitochondrial transfection. Here we report the intracellular delivery of exogenous DNA localized to the mitochondria of Arabidopsis thaliana using a combination of mitochondria-targeting peptide and cell-penetrating peptide. Low concentrations of peptides were sufficient to deliver DNA into the mitochondria and expression of imported DNA reached detectable levels within a short incubation period (12 h). We found that electrostatic interaction with the cell membrane is not a critical factor for complex internalization, instead, improved intracellular penetration of mitochondria-targeted complexes significantly enhanced gene transfer efficiency. Our results delineate a simple and effective peptide-based method, as a starting point for the development of more sophisticated plant mitochondrial transfection strategies.

  8. Gene introduction into the mitochondria of Arabidopsis thaliana via peptide-based carriers

    Science.gov (United States)

    Chuah, Jo-Ann; Yoshizumi, Takeshi; Kodama, Yutaka; Numata, Keiji

    2015-01-01

    Available methods in plant genetic transformation are nuclear and plastid transformations because similar procedures have not yet been established for the mitochondria. The double membrane and small size of the organelle, in addition to its large population in cells, are major obstacles in mitochondrial transfection. Here we report the intracellular delivery of exogenous DNA localized to the mitochondria of Arabidopsis thaliana using a combination of mitochondria-targeting peptide and cell-penetrating peptide. Low concentrations of peptides were sufficient to deliver DNA into the mitochondria and expression of imported DNA reached detectable levels within a short incubation period (12 h). We found that electrostatic interaction with the cell membrane is not a critical factor for complex internalization, instead, improved intracellular penetration of mitochondria-targeted complexes significantly enhanced gene transfer efficiency. Our results delineate a simple and effective peptide-based method, as a starting point for the development of more sophisticated plant mitochondrial transfection strategies.

  9. Identification and structural analysis of a novel snoRNA gene cluster from Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    周惠; 孟清; 屈良鹄

    2000-01-01

    A 22 snoRNA gene cluster, consisting of four antisense snoRNA genes, was identified from Arabidopsis thaliana. The sequence and structural analysis showed that the 22 snoRNA gene cluster might be transcribed as a polycistronic precursor from an upstream promoter, and the in-tergenic spacers of the gene cluster encode the ’hairpin’ structures similar to the processing recognition signals of yeast Saccharomyces cerevisiae polycistronic snoRNA precursor. The results also revealed that plant snoRNA gene with multiple copies is a characteristic in common, and provides a good system for further revealing the transcription and expression mechanism of plant snoRNA gene cluster.

  10. Molecular phenotyping of the pal1 and pal2 mutants of Arabidopsis thaliana reveals far-reaching consequences on phenylpropanoid, amino acid, and carbohydrate metabolism

    OpenAIRE

    Rohde, Antje; Morreel, Kris; Ralph, John; Goeminne, Geert; Hostyn, Vanessa; De Rycke, Riet; Kushnir, Sergei; Van Doorsselaere, Jan; Joseleau, Jean-Paul; Vuylsteke, Marnik; Van Driessche, Gonzalez; Van Beeumen, Jozef; Messens, Eric; Boerjan, Wout

    2004-01-01

    The first enzyme of the phenylpropanoid pathway, Phe ammonia-lyase (PAL), is encoded by four genes in Arabidopsis thaliana. Whereas PAL function is well established in various plants, an insight into the functional significance of individual gene family members is lacking. We show that in the absence of clear phenotypic alterations in the Arabidopsis pall and pal2 single mutants and with limited phenotypic alterations in the pall pal2 double mutant, significant modifications occur in the tran...

  11. The ABC transporter BcatrB from Botrytis cinerea exports camalexin and is a virulence factor on Arabidopsis thaliana.

    Science.gov (United States)

    Stefanato, Francesca L; Abou-Mansour, Eliane; Buchala, Antony; Kretschmer, Matthias; Mosbach, Andreas; Hahn, Matthias; Bochet, Christian G; Métraux, Jean-Pierre; Schoonbeek, Henk-jan

    2009-05-01

    Arabidopsis thaliana is known to produce the phytoalexin camalexin in response to abiotic and biotic stress. Here we studied the mechanisms of tolerance to camalexin in the fungus Botrytis cinerea, a necrotrophic pathogen of A. thaliana. Exposure of B. cinerea to camalexin induces expression of BcatrB, an ABC transporter that functions in the efflux of fungitoxic compounds. B. cinerea inoculated on wild-type A. thaliana plants yields smaller lesions than on camalexin-deficient A. thaliana mutants. A B. cinerea strain lacking functional BcatrB is more sensitive to camalexin in vitro and less virulent on wild-type plants, but is still fully virulent on camalexin-deficient mutants. Pre-treatment of A. thaliana with UV-C leads to increased camalexin accumulation and substantial resistance to B. cinerea. UV-C-induced resistance was not seen in the camalexin-deficient mutants cyp79B2/B3, cyp71A13, pad3 or pad2, and was strongly reduced in ups1. Here we demonstrate that an ABC transporter is a virulence factor that increases tolerance of the pathogen towards a phytoalexin, and the complete restoration of virulence on host plants lacking this phytoalexin.

  12. Complementation of the pha2 yeast mutant suggests functional differences for arogenate dehydratases from Arabidopsis thaliana.

    Science.gov (United States)

    Bross, Crystal D; Corea, Oliver R A; Kaldis, Angelo; Menassa, Rima; Bernards, Mark A; Kohalmi, Susanne E

    2011-08-01

    The final steps of phenylalanine (Phe) biosynthesis in bacteria, fungi and plants can occur via phenylpyruvate or arogenate intermediates. These routes are determined by the presence of prephenate dehydratase (PDT, EC4.2.1.51), which forms phenylpyruvate from prephenate, or arogenate dehydratase (ADT, EC4.2.1.91), which forms phenylalanine directly from arogenate. We compared sequences from select yeast species to those of Arabidopsis thaliana. The in silico analysis showed that plant ADTs and yeast PDTs share many common features allowing them to act as dehydratase/decarboxylases. However, plant and yeast sequences clearly group independently conferring distinct substrate specificities. Complementation of the Saccharomyces cerevisiae pha2 mutant, which lacks PDT activity and cannot grow in the absence of exogenous Phe, was used to test the PDT activity of A. thaliana ADTs in vivo. Previous biochemical characterization showed that all six AtADTs had high catalytic activity with arogenate as a substrate, while AtADT1, AtADT2 and AtADT6 also had limited activity with prephenate. Consistent with these results, the complementation test showed AtADT2 readily recovered the pha2 phenotype after ∼6 days growth at 30 °C, while AtADT1 required ∼13 days to show visible growth. By contrast, AtADT6 (lowest PDT activity) and AtADT3-5 (no PDT activity) were unable to recover the phenotype. These results suggest that only AtADT1 and AtADT2, but not the other four ADTs from Arabidopsis, have functional PDT activity in vivo, showing that there are two functional distinct groups. We hypothesize that plant ADTs have evolved to use the arogenate route for Phe synthesis while keeping some residual PDT activity.

  13. Activity and Crystal Structure of Arabidopsis thalianaUDP-N-Acetylglucosamine Acyltransferase

    Energy Technology Data Exchange (ETDEWEB)

    Joo, Sang Hoon; Chung, Hak Suk; Raetz, Christian R.H.; Garrett, Teresa A. (Vassar); (CUD- South Korea); (Duke)

    2012-08-31

    The UDP-N-acetylglucosamine (UDP-GlcNAc) acyltransferase, encoded by lpxA, catalyzes the first step of lipid A biosynthesis in Gram-negative bacteria, the (R)-3-hydroxyacyl-ACP-dependent acylation of the 3-OH group of UDP-GlcNAc. Recently, we demonstrated that the Arabidopsis thaliana orthologs of six enzymes of the bacterial lipid A pathway produce lipid A precursors with structures similar to those of Escherichia coli lipid A precursors [Li, C., et al. (2011) Proc. Natl. Acad. Sci. U.S.A. 108, 11387-11392]. To build upon this finding, we have cloned, purified, and determined the crystal structure of the A. thaliana LpxA ortholog (AtLpxA) to 2.1 {angstrom} resolution. The overall structure of AtLpxA is very similar to that of E. coli LpxA (EcLpxA) with an {alpha}-helical-rich C-terminus and characteristic N-terminal left-handed parallel {beta}-helix (L{beta}H). All key catalytic and chain length-determining residues of EcLpxA are conserved in AtLpxA; however, AtLpxA has an additional coil and loop added to the L{beta}H not seen in EcLpxA. Consistent with the similarities between the two structures, purified AtLpxA catalyzes the same reaction as EcLpxA. In addition, A. thaliana lpxA complements an E. coli mutant lacking the chromosomal lpxA and promotes the synthesis of lipid A in vivo similar to the lipid A produced in the presence of E. coli lpxA. This work shows that AtLpxA is a functional UDP-GlcNAc acyltransferase that is able to catalyze the same reaction as EcLpxA and supports the hypothesis that lipid A molecules are biosynthesized in Arabidopsis and other plants.

  14. Hydroxyproline O-arabinosyltransferase mutants oppositely alter tip growth in Arabidopsis thaliana and Physcomitrella patens.

    Science.gov (United States)

    MacAlister, Cora A; Ortiz-Ramírez, Carlos; Becker, Jörg D; Feijó, José A; Lippman, Zachary B

    2016-01-01

    Hydroxyproline O-arabinosyltransferases (HPATs) are members of a small, deeply conserved family of plant-specific glycosyltransferases that add arabinose sugars to diverse proteins including cell wall-associated extensins and small signaling peptides. Recent genetic studies in flowering plants suggest that different HPAT homologs have been co-opted to function in diverse species-specific developmental contexts. However, nothing is known about the roles of HPATs in basal plants. We show that complete loss of HPAT function in Arabidopsis thaliana and the moss Physcomitrella patens results in a shared defect in gametophytic tip cell growth. Arabidopsis hpat1/2/3 triple knockout mutants suffer from a strong male sterility defect as a consequence of pollen tubes that fail to fully elongate following pollination. Knocking out the two HPAT genes of Physcomitrella results in larger multicellular filamentous networks due to increased elongation of protonemal tip cells. Physcomitrella hpat mutants lack cell-wall associated hydroxyproline arabinosides and can be rescued with exogenous cellulose, while global expression profiling shows that cell wall-associated genes are severely misexpressed, implicating a defect in cell wall formation during tip growth. Our findings point to a major role for HPATs in influencing cell elongation during tip growth in plants.

  15. A Non-canonical Transferred DNA Insertion at the BRI 1 Locus in Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    Zhong Zhao; Yan Zhu; Mathieu Erhardt; Ying Ruan; Wen-Hui Shen

    2009-01-01

    Agrobacterium-mediated transformation is widely used in transgenic plant englnserlng and has been proven to be a powerful tool for insertional mutagenesis of the plant genome.The transferred DNA (T-DNA) from Agrobacterlum is Integrated into the plant genome through illegitimate recombination between the T-DNA and the plant DNA.Contrasting to the canonical insertion,here we report on a locus showing a complex mutation associated with T-DNA insertion at the BRI 1 gene in Arabidopsis thaliana.We obtained a mutant line,named salade for its phenotype of dwarf stature and proliferating rosette,Molecular charactedzation of this mutant revealed that in addition to T-DNA a non.T.DNA-Iocalized transposon from bacteda was inserted in the Arabidopsis genome and that a region of more than 11.5 kb of the Arebidopsis genome was deleted at the insertion site.The deleted region contains the brassinosteroid receptor gene BRI 1 and the transcdption factor gene WRKY13.Our finding reveals non-canonical T-DNA insertion,implicating horizontal gene transfer and cautioning the use of T-DNA as mutagen in transgenic research.

  16. A WD40-repeat gene from Malus x domestica is a functional homologue of Arabidopsis thaliana TRANSPARENT TESTA GLABRA1.

    Science.gov (United States)

    Brueggemann, Julian; Weisshaar, Bernd; Sagasser, Martin

    2010-03-01

    The WD40 repeat protein TRANSPARENT TESTA GLABRA1 (TTG1) is involved in a multitude of developmental and biochemical reactions in Arabidopsis thaliana such as the production of seed coat colour and mucilage, pigmentation by anthocyanins as well as the formation of trichomes and root hairs. In this study, a putative TTG1 homologue was isolated from apple (Malus x domestica Borkh.) showing 80.2% identity to A. thaliana TTG1 on nucleotide and 90.7% similarity on amino acid level. The MdTTG1 candidate was able to activate the AtBAN promoter in cooperation with the A. thaliana transcription factors TT2 and TT8 in A. thaliana protoplasts. This indicates that the encoded protein can be integrated into the complex that activates BAN in A. thaliana, and that a similar complex might also be present in apple. When transformed into ttg1 mutants of A. thaliana, the apple sequence was able to restore trichome growth, anthocyanin production in young seedlings as well as proanthocyanidin production in seeds. Additionally, roots of complemented mutant plants showed root hair formation resembling wild type. These results show that the studied apple WD40 gene is a functional homologue of AtTTG1 and we refer to this gene as MdTTG1.

  17. Composition and function of P bodies in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Luis David Maldonado-Bonilla

    2014-05-01

    Full Text Available mRNA accumulation is tightly regulated by diverse molecular pathways. The identification and characterization of enzymes and regulatory proteins involved in controlling the fate of mRNA offers the possibility to broaden our understanding of posttranscriptional gene regulation. Processing bodies (P bodies, PB are cytoplasmic protein complexes involved in degradation and translational arrest of mRNA. Composition and dynamics of these subcellular structures have been studied in animal systems, yeasts and in the model plant Arabidopsis. Their assembly implies the aggregation of specific factors related to decapping, deadenylation and exoribonucleases that operate synchronously to regulate certain mRNA targets during development and adaptation to stress. Although the general function of PB along with the flow of genetic information is understood, several questions still remain open. This review summarizes data on the composition, potential molecular roles, and biological significance of PB and potentially related proteins in Arabidopsis.

  18. PYK10 myrosinase reveals a functional coordination between endoplasmic reticulum bodies and glucosinolates in Arabidopsis thaliana.

    Science.gov (United States)

    Nakano, Ryohei T; Piślewska-Bednarek, Mariola; Yamada, Kenji; Edger, Patrick P; Miyahara, Mado; Kondo, Maki; Böttcher, Christoph; Mori, Masashi; Nishimura, Mikio; Schulze-Lefert, Paul; Hara-Nishimura, Ikuko; Bednarek, Paweł

    2017-01-01

    The endoplasmic reticulum body (ER body) is an organelle derived from the ER that occurs in only three families of the order Brassicales and is suggested to be involved in plant defense. ER bodies in Arabidopsis thaliana contain large amounts of β-glucosidases, but the physiological functions of ER bodies and these enzymes remain largely unclear. Here we show that PYK10, the most abundant β-glucosidase in A. thaliana root ER bodies, hydrolyzes indole glucosinolates (IGs) in addition to the previously reported in vitro substrate scopolin. We found a striking co-expression between ER body-related genes (including PYK10), glucosinolate biosynthetic genes and the genes for so-called specifier proteins affecting the terminal products of myrosinase-mediated glucosinolate metabolism, indicating that these systems have been integrated into a common transcriptional network. Consistent with this, comparative metabolite profiling utilizing a number of A. thaliana relatives within Brassicaceae identified a clear phylogenetic co-occurrence between ER bodies and IGs, but not between ER bodies and scopolin. Collectively, our findings suggest a functional link between ER bodies and glucosinolate metabolism in planta. In addition, in silico three-dimensional modeling, combined with phylogenomic analysis, suggests that PYK10 represents a clade of 16 myrosinases that arose independently from the other well-documented class of six thioglucoside glucohydrolases. These findings provide deeper insights into how glucosinolates are metabolized in cruciferous plants and reveal variation of the myrosinase-glucosinolate system within individual plants. © 2016 The Authors The Plant Journal © 2016 John Wiley & Sons Ltd.

  19. Reciprocal transplants demonstrate strong adaptive differentiation of the model organism Arabidopsis thaliana in its native range.

    Science.gov (United States)

    Agren, Jon; Schemske, Douglas W

    2012-06-01

    To quantify adaptive differentiation in the model plant Arabidopsis thaliana, we conducted reciprocal transplant experiments for five years between two European populations, one near the northern edge of the native range (Sweden) and one near the southern edge (Italy). We planted seeds (years 1-3) and seedlings (years 4-5), and estimated fitness as the number of fruits produced per seed or seedling planted. In eight of the 10 possible site × year comparisons, the fitness of the local population was significantly higher than that of the nonlocal population (3.1-22.2 times higher at the southern site, and 1.7-3.6 times higher at the northern site); in the remaining two comparisons no significant difference was recorded. At both sites, the local genotype had higher survival than the nonlocal genotype, and at the Italian site, the local genotype also had higher fecundity. Across years, the relative survival of the Italian genotype at the northern site decreased with decreasing winter soil temperature. The results provide evidence of strong adaptive differentiation between natural populations of A. thaliana and indicate that differences in tolerance to freezing contributed to fitness variation at the northern site. In ongoing work, we explore the functional and genetic basis of this adaptive differentiation.

  20. Artificial Autopolyploidization Modifies the Tricarboxylic Acid Cycle and GABA Shunt in Arabidopsis thaliana Col-0

    Science.gov (United States)

    Vergara, Fredd; Kikuchi, Jun; Breuer, Christian

    2016-05-01

    Autopolyploidy is a process whereby the chromosome set is multiplied and it is a common phenomenon in angiosperms. Autopolyploidy is thought to be an important evolutionary force that has led to the formation of new plant species. Despite its relevance, the consequences of autopolyploidy in plant metabolism are poorly understood. This study compares the metabolic profiles of natural diploids and artificial autotetraploids of Arabidopsis thaliana Col-0. Different physiological parameters are compared between diploids and autotetraploids using nuclear magnetic resonance (NMR), elemental analysis (carbon:nitrogen balance) and quantitative real-time PCR (qRT-PCR). The main difference between diploid and autotetraploid A. thaliana Col-0 is observed in the concentration of metabolites related to the tricarboxylic acid cycle (TCA) and γ-amino butyric acid (GABA) shunt, as shown by multivariate statistical analysis of NMR spectra. qRT-PCR shows that genes related to the TCA and GABA shunt are also differentially expressed between diploids and autotetraploids following similar trends as their corresponding metabolites. Solid evidence is presented to demonstrate that autopolyploidy influences core plant metabolic processes.

  1. Putrescine accumulation in Arabidopsis thaliana transgenic lines enhances tolerance to dehydration and freezing stress.

    Science.gov (United States)

    Alet, Analía I; Sanchez, Diego H; Cuevas, Juan C; Del Valle, Secundino; Altabella, Teresa; Tiburcio, Antonio F; Marco, Francisco; Ferrando, Alejandro; Espasandín, Fabiana D; González, María E; Ruiz, Oscar A; Carrasco, Pedro

    2011-02-01

    Polyamines have been globally associated to plant responses to abiotic stress. Particularly, putrescine has been related to a better response to cold and dehydration stresses. It is known that this polyamine is involved in cold tolerance, since Arabidopsis thaliana plants mutated in the key enzyme responsible for putrescine synthesis (arginine decarboxilase, ADC; EC 4.1.1.19) are more sensitive than the wild type to this stress. Although it is speculated that the over-expression of ADC genes may confer tolerance, this is hampered by pleiotropic effects arising from the constitutive expression of enzymes from the polyamine metabolism. Here, we present our work using A. thaliana transgenic plants harboring the ADC gene from oat under the control of a stress-inducible promoter (pRD29A) instead of a constitutive promoter. The transgenic lines presented in this work were more resistant to both cold and dehydration stresses, associated with a concomitant increment in endogenous putrescine levels under stress. Furthermore, the increment in putrescine upon cold treatment correlated with the induction of known stress-responsive genes, and suggested that putrescine may be directly or indirectly involved in ABA metabolism and gene expression.

  2. Phase response of the Arabidopsis thaliana circadian clock to light pulses of different wavelengths.

    Science.gov (United States)

    Ohara, Takayuki; Fukuda, Hirokazu; Tokuda, Isao T

    2015-04-01

    Light is known as one of the most powerful environmental time cues for the circadian system. The quality of light is characterized by its intensity and wavelength. We examined how the phase response of Arabidopsis thaliana depends on the wavelength of the stimulus light and the type of light perturbation. Using transgenic A. thaliana expressing a luciferase gene, we monitored the rhythm of the bioluminescence signal. We stimulated the plants under constant red light using 3 light perturbation treatments: (1) increasing the red light intensity, (2) turning on a blue light while turning off the red light, and (3) turning on a blue light while keeping the red light on. To examine the phase response properties, we generated a phase transition curve (PTC), which plots the phase after the perturbation as a function of the phase before the perturbation. To evaluate the effect of the 3 light perturbation treatments, we simulated PTCs using a mathematical model of the plant circadian clock and fitted the simulated PTCs to the experimentally measured PTCs. Among the 3 treatments, perturbation (3) provided the strongest stimulus. The results indicate that the color of the stimulus light and the type of pulse administration affect the phase response in a complex manner. Moreover, the results suggest the involvement of interaction between red and blue light signaling pathways in resetting of the plant circadian clock. © 2015 The Author(s).

  3. Artificial Autopolyploidization Modifies the Tricarboxylic Acid Cycle and GABA Shunt in Arabidopsis thaliana Col-0.

    Science.gov (United States)

    Vergara, Fredd; Kikuchi, Jun; Breuer, Christian

    2016-05-23

    Autopolyploidy is a process whereby the chromosome set is multiplied and it is a common phenomenon in angiosperms. Autopolyploidy is thought to be an important evolutionary force that has led to the formation of new plant species. Despite its relevance, the consequences of autopolyploidy in plant metabolism are poorly understood. This study compares the metabolic profiles of natural diploids and artificial autotetraploids of Arabidopsis thaliana Col-0. Different physiological parameters are compared between diploids and autotetraploids using nuclear magnetic resonance (NMR), elemental analysis (carbon:nitrogen balance) and quantitative real-time PCR (qRT-PCR). The main difference between diploid and autotetraploid A. thaliana Col-0 is observed in the concentration of metabolites related to the tricarboxylic acid cycle (TCA) and γ-amino butyric acid (GABA) shunt, as shown by multivariate statistical analysis of NMR spectra. qRT-PCR shows that genes related to the TCA and GABA shunt are also differentially expressed between diploids and autotetraploids following similar trends as their corresponding metabolites. Solid evidence is presented to demonstrate that autopolyploidy influences core plant metabolic processes.

  4. Cytochemical localization of reserves during seed development in Arabidopsis thaliana under spaceflight conditions

    Science.gov (United States)

    Kuang, A.; Xiao, Y.; Musgrave, M. E.

    1996-01-01

    Successful development of seeds under spaceflight conditions has been an elusive goal of numerous long-duration experiments with plants on orbital spacecraft. Because carbohydrate metabolism undergoes changes when plants are grown in microgravity, developing seed storage reserves might be detrimentally affected during spaceflight. Seed development in Arabidopsis thaliana plants that flowered during 11 d in space on shuttle mission STS-68 has been investigated in this study. Plants were grown to the rosette stage (13 d) on a nutrient agar medium on the ground and loaded into the Plant Growth Unit flight hardware 18 h prior to lift-off. Plants were retrieved 3 h after landing and siliques were immediately removed from plants. Young seeds were fixed and processed for microscopic observation. Seeds in both the ground control and flight plants are similar in their morphology and size. The oldest seeds from these plants contain completely developed embryos and seed coats. These embryos developed radicle, hypocotyl, meristematic apical tissue, and differentiated cotyledons. Protoderm, procambium, and primary ground tissue had differentiated. Reserves such as starch and protein were deposited in the embryos during tissue differentiation. The aleurone layer contains a large quantity of storage protein and starch grains. A seed coat developed from integuments of the ovule with gradual change in cell composition and cell material deposition. Carbohydrates were deposited in outer integument cells especially in the outside cell walls. Starch grains decreased in number per cell in the integument during seed coat development. All these characteristics during seed development represent normal features in the ground control plants and show that the spaceflight environment does not prevent normal development of seeds in Arabidopsis.

  5. Transcriptome Analysis of Induced Systemic Drought Tolerance Elicited by Pseudomonas chlororaphis O6 in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Song-Mi Cho

    2013-06-01

    Full Text Available Root colonization by Pseudomonas chlororaphis O6 induces systemic drought tolerance in Arabidopsis thaliana. Microarray analysis was performed using the 22,800-gene Affymetrix GeneChips to identify differentially-expressed genes from plants colonized with or without P. chlororaphis O6 under drought stressed conditions or normal growth conditions. Root colonization in plants grown under regular irrigation condition increased transcript accumulation from genes associated with defense, response to reactive oxygen species, and auxin- and jasmonic acid-responsive genes, but decreased transcription factors associated with ethylene and abscisic acid signaling. The cluster of genes involved in plant disease resistance were up-regulated, but the set of drought signaling response genes were down-regulated in the P. chlororaphis O6-colonized under drought stress plants compared to those of the drought stressed plants without bacterial treatment. Transcripts of the jasmonic acid-marker genes, VSP1 and pdf-1.2, the salicylic acid regulated gene, PR-1, and the ethylene-response gene, HEL, also were up-regulated in plants colonized by P. chlororaphis O6, but differed in their responsiveness to drought stress. These data show how gene expression in plants lacking adequate water can be remarkably influenced by microbial colonization leading to plant protection, and the activation of the plant defense signal pathway induced by root colonization of P. chlororaphis O6 might be a key element for induced systemic tolerance by microbes.

  6. Increased root hair density by loss of WRKY6 in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Markus G. Stetter

    2017-01-01

    Full Text Available Root hairs are unicellular elongations of certain rhizodermal cells that improve the uptake of sparingly soluble and immobile soil nutrients. Among different Arabidopsis thaliana genotypes, root hair density, length and the local acclimation to low inorganic phosphate (Pi differs considerably, when analyzed on split agar plates. Here, genome-wide association fine mapping identified significant single nucleotide polymorphisms associated with the increased root hair density in the absence of local phosphate on chromosome 1. A loss-of-functionmutant of the candidate transcription factor gene WRKY6, which is involved in the acclimation of plants to low phosphorus, had increased root hair density. This is partially explained by a reduced cortical cell diameter in wrky6-3, reducing the rhizodermal cell numbers adjacent to the cortical cells. As a consequence, rhizodermal cells in positions that are in contact with two cortical cells are found more often, leading to higher hair density. Distinct cortical cell diameters and epidermal cell lengths distinguish other Arabidopsis accessions with distinct root hair density and −Pi response from diploid Col-0, while tetraploid Col-0 had generally larger root cell sizes, which explain longer hairs. A distinct radial root morphology within Arabidopsis accessions and wrky6-3explains some, but not all, differences in the root hair acclimation to –Pi.

  7. Increased root hair density by loss of WRKY6 in Arabidopsis thaliana

    Science.gov (United States)

    Benz, Martin

    2017-01-01

    Root hairs are unicellular elongations of certain rhizodermal cells that improve the uptake of sparingly soluble and immobile soil nutrients. Among different Arabidopsis thaliana genotypes, root hair density, length and the local acclimation to low inorganic phosphate (Pi) differs considerably, when analyzed on split agar plates. Here, genome-wide association fine mapping identified significant single nucleotide polymorphisms associated with the increased root hair density in the absence of local phosphate on chromosome 1. A loss-of-functionmutant of the candidate transcription factor gene WRKY6, which is involved in the acclimation of plants to low phosphorus, had increased root hair density. This is partially explained by a reduced cortical cell diameter in wrky6-3, reducing the rhizodermal cell numbers adjacent to the cortical cells. As a consequence, rhizodermal cells in positions that are in contact with two cortical cells are found more often, leading to higher hair density. Distinct cortical cell diameters and epidermal cell lengths distinguish other Arabidopsis accessions with distinct root hair density and −Pi response from diploid Col-0, while tetraploid Col-0 had generally larger root cell sizes, which explain longer hairs. A distinct radial root morphology within Arabidopsis accessions and wrky6-3explains some, but not all, differences in the root hair acclimation to –Pi. PMID:28149680

  8. An improved method for the visualization of conductive vessels in Arabidopsis thaliana inflorescence stems

    Directory of Open Access Journals (Sweden)

    Radek eJupa

    2015-04-01

    Full Text Available Dye perfusion is commonly used for the identification of conductive elements important for the study of xylem development as well as precise hydraulic estimations. The tiny size of inflorescence stems, the small amount of vessels in close arrangement, and high hydraulic resistivity delimit the use of the method for quantification of the water conductivity of Arabidopsis thaliana, one of the recently most extensively used plant models. Here, we present an extensive adjustment to the method in order to reliably identify individual functional (conductive vessels. Segments of inflorescence stems were sealed in silicone tubes to prevent damage and perfused with a dye solution. Our results showed that dyes often used for staining functional xylem elements (safranin, fuchsine, toluidine blue failed with Arabidopsis. In contrast, Fluorescent Brightener 28 dye solution perfused through segments stained secondary cell walls of functional vessels, which were clearly distinguishable in native cross sections. When compared to identification based on the degree of development of secondary cell walls, identification with the help of dye perfusion revealed a significantly lower number of functional vessels and values of theoretical hydraulic conductivity. We found that lignified but not yet functional vessels form a substantial portion of the xylem in apical and basal segments of Arabidopsis and, thus, significantly affect the analyzed functional parameters of xylem. The presented methodology enables reliable identification of individual functional vessels, allowing thus estimations of hydraulic conductivities to be improved, size distributions and vessel diameters to be refined, and data variability generally to be reduced.

  9. Brassica oleracea MATE encodes a citrate transporter and enhances aluminum tolerance in Arabidopsis thaliana.

    Science.gov (United States)

    Wu, Xinxin; Li, Ren; Shi, Jin; Wang, Jinfang; Sun, Qianqian; Zhang, Haijun; Xing, Yanxia; Qi, Yan; Zhang, Na; Guo, Yang-Dong

    2014-08-01

    The secretion of organic acid anions from roots is an important mechanism for plant aluminum (Al) tolerance. Here we report cloning and characterizing BoMATE (KF031944), a multidrug and toxic compound extrusion (MATE) family gene from cabbage (Brassica oleracea). The expression of BoMATE was more abundant in roots than in shoots, and it was highly induced by Al treatment. The (14)C-citrate efflux experiments in oocytes demonstrated that BoMATE is a citrate transporter. Electrophysiological analysis and SIET analysis of Xenopus oocytes expressing BoMATE indicated BoMATE is activated by Al. Transient expression of BoMATE in onion epidermal cells demonstrated that it localized to the plasma membrane. Compared with the wild-type Arabidopsis, the transgenic lines constitutively overexpressing BoMATE enhanced Al tolerance and increased citrate secretion. In addition, Arabidopsis transgenic lines had a lower K(+) efflux and higher H(+) efflux, in the presence of Al, than control wild type in the distal elongation zone (DEZ). This is the first direct evidence that MATE protein is involved in the K(+) and H(+) flux in response to Al treatment. Taken together, our results show that BoMATE is an Al-induced citrate transporter and enhances aluminum tolerance in Arabidopsis thaliana.

  10. The re-establishment of desiccation tolerance in germinated Arabidopsis thaliana seeds and its associated transcriptome.

    Science.gov (United States)

    Maia, Julio; Dekkers, Bas J W; Provart, Nicholas J; Ligterink, Wilco; Hilhorst, Henk W M

    2011-01-01

    The combination of robust physiological models with "omics" studies holds promise for the discovery of genes and pathways linked to how organisms deal with drying. Here we used a transcriptomics approach in combination with an in vivo physiological model of re-establishment of desiccation tolerance (DT) in Arabidopsis thaliana seeds. We show that the incubation of desiccation sensitive (DS) germinated Arabidopsis seeds in a polyethylene glycol (PEG) solution re-induces the mechanisms necessary for expression of DT. Based on a SNP-tile array gene expression profile, our data indicates that the re-establishment of DT, in this system, is related to a programmed reversion from a metabolic active to a quiescent state similar to prior to germination. Our findings show that transcripts of germinated seeds after the PEG-treatment are dominated by those encoding LEA, seed storage and dormancy related proteins. On the other hand, a massive repression of genes belonging to many other classes such as photosynthesis, cell wall modification and energy metabolism occurs in parallel. Furthermore, comparison with a similar system for Medicago truncatula reveals a significant overlap between the two transcriptomes. Such overlap may highlight core mechanisms and key regulators of the trait DT. Taking into account the availability of the many genetic and molecular resources for Arabidopsis, the described system may prove useful for unraveling DT in higher plants.

  11. The re-establishment of desiccation tolerance in germinated Arabidopsis thaliana seeds and its associated transcriptome.

    Directory of Open Access Journals (Sweden)

    Julio Maia

    Full Text Available The combination of robust physiological models with "omics" studies holds promise for the discovery of genes and pathways linked to how organisms deal with drying. Here we used a transcriptomics approach in combination with an in vivo physiological model of re-establishment of desiccation tolerance (DT in Arabidopsis thaliana seeds. We show that the incubation of desiccation sensitive (DS germinated Arabidopsis seeds in a polyethylene glycol (PEG solution re-induces the mechanisms necessary for expression of DT. Based on a SNP-tile array gene expression profile, our data indicates that the re-establishment of DT, in this system, is related to a programmed reversion from a metabolic active to a quiescent state similar to prior to germination. Our findings show that transcripts of germinated seeds after the PEG-treatment are dominated by those encoding LEA, seed storage and dormancy related proteins. On the other hand, a massive repression of genes belonging to many other classes such as photosynthesis, cell wall modification and energy metabolism occurs in parallel. Furthermore, comparison with a similar system for Medicago truncatula reveals a significant overlap between the two transcriptomes. Such overlap may highlight core mechanisms and key regulators of the trait DT. Taking into account the availability of the many genetic and molecular resources for Arabidopsis, the described system may prove useful for unraveling DT in higher plants.

  12. Enhancement of Thiamin Content in Arabidopsis thaliana by Metabolic Engineering.

    Science.gov (United States)

    Dong, Wei; Stockwell, Virginia O; Goyer, Aymeric

    2015-12-01

    Thiamin is an essential nutrient in the human diet. Severe thiamin deficiency leads to beriberi, a lethal disease which is common in developing countries. Thiamin biofortification of staple food crops is a possible strategy to alleviate thiamin deficiency-related diseases. In plants, thiamin plays a role in the response to abiotic and biotic stresses, and data from the literature suggest that boosting thiamin content could increase resistance to stresses. Here, we tested an engineering strategy to increase thiamin content in Arabidopsis. Thiamin is composed of a thiazole ring linked to a pyrimidine ring by a methylene bridge. THI1 and THIC are the first committed steps in the synthesis of the thiazole and pyrimidine moieties, respectively. Arabidopsis plants were transformed with a vector containing the THI1-coding sequence under the control of a constitutive promoter. Total thiamin leaf content in THI1 plants was up approximately 2-fold compared with the wild type. THI1-overexpressing lines were then crossed with pre-existing THIC-overexpressing lines. Resulting THI1 × THIC plants accumulated up to 3.4- and 2.6-fold more total thiamin than wild-type plants in leaf and seeds, respectively. After inoculation with Pseudomonas syringae, THI1 × THIC plants had lower populations than the wild-type control. However, THI1 × THIC plants subjected to various abiotic stresses did not show any visible or biochemical changes compared with the wild type. We discuss the impact of engineering thiamin biosynthesis on the nutritional value of plants and their resistance to biotic and abiotic stresses.

  13. Regulation of Arabidopsis thaliana 5S rRNA Genes.

    Science.gov (United States)

    Vaillant, Isabelle; Tutois, Sylvie; Cuvillier, Claudine; Schubert, Ingo; Tourmente, Sylvette

    2007-05-01

    The Arabidopsis thaliana genome comprises around 1,000 copies of 5S rRNA genes encoding both major and minor 5S rRNAs. In mature wild-type leaves, the minor 5S rRNA genes are silent. Using different mutants of DNA methyltransferases (met1, cmt3 and met1 cmt3), components of the RNAi pathway (ago4) or post-translational histone modifier (hda6/sil1), we show that the corresponding proteins are needed to maintain proper methylation patterns at heterochromatic 5S rDNA repeats. Using reverse transcription-PCR and cytological analyses, we report that a decrease of 5S rDNA methylation at CG or CNG sites in these mutants leads to the release of 5S rRNA gene silencing which occurred without detectable changes of the 5S rDNA chromatin structure. In spite of severely reduced DNA methylation, the met1 cmt3 double mutant revealed no increase in minor 5S rRNA transcripts. Furthermore, the release of silencing of minor 5S rDNAs can be achieved without increased formation of euchromatic loops by 5S rDNA, and is independent from the global heterochromatin content. Additionally, fluorescence in situ hybridization with centromeric 180 bp repeats confirmed that these highly repetitive sequences, in spite of their elevated transcriptional activity in the DNA methyltransferase mutants (met1, cmt3 and met1 cmt3), remain within chromocenters of the mutant nuclei.

  14. Genetic architecture of nonadditive inheritance in Arabidopsis thaliana hybrids.

    Science.gov (United States)

    Seymour, Danelle K; Chae, Eunyoung; Grimm, Dominik G; Martín Pizarro, Carmen; Habring-Müller, Anette; Vasseur, François; Rakitsch, Barbara; Borgwardt, Karsten M; Koenig, Daniel; Weigel, Detlef

    2016-11-15

    The ubiquity of nonparental hybrid phenotypes, such as hybrid vigor and hybrid inferiority, has interested biologists for over a century and is of considerable agricultural importance. Although examples of both phenomena have been subject to intense investigation, no general model for the molecular basis of nonadditive genetic variance has emerged, and prediction of hybrid phenotypes from parental information continues to be a challenge. Here we explore the genetics of hybrid phenotype in 435 Arabidopsis thaliana individuals derived from intercrosses of 30 parents in a half diallel mating scheme. We find that nonadditive genetic effects are a major component of genetic variation in this population and that the genetic basis of hybrid phenotype can be mapped using genome-wide association (GWA) techniques. Significant loci together can explain as much as 20% of phenotypic variation in the surveyed population and include examples that have both classical dominant and overdominant effects. One candidate region inherited dominantly in the half diallel contains the gene for the MADS-box transcription factor AGAMOUS-LIKE 50 (AGL50), which we show directly to alter flowering time in the predicted manner. Our study not only illustrates the promise of GWA approaches to dissect the genetic architecture underpinning hybrid performance but also demonstrates the contribution of classical dominance to genetic variance.

  15. Spontaneous mutation parameters for Arabidopsis thaliana measured in the wild.

    Science.gov (United States)

    Rutter, Matthew T; Shaw, Frank H; Fenster, Charles B

    2010-06-01

    Mutations are the ultimate source of genetic diversity and their contributions to evolutionary process depend critically on their rate and their effects on traits, notably fitness. Mutation rate and mutation effect can be measured simultaneously through the use of mutation accumulation lines, and previous mutation accumulation studies measuring these parameters have been performed in laboratory conditions. However, estimation of mutation parameters for fitness in wild populations requires assays in environments where mutations are exposed to natural selection and natural environmental variation. Here we quantify mutation parameters in both the wild and greenhouse environments using 100 25th generation Arabidopsis thaliana mutation accumulation lines. We found significantly greater mutational variance and a higher mutation rate for fitness under field conditions relative to greenhouse conditions. However, our field estimates were low when scaled to natural environmental variation. Many of the mutation accumulation lines have increased fitness, counter to the expectation that nearly all mutations decrease fitness. A high mutation rate and a low mutational contribution to phenotypic variation may explain observed levels of natural genetic variation. Our findings indicate that mutation parameters are not fixed, but are variables whose values may reflect the specific environment in which mutations are tested.

  16. Expression of the Znt1 zinc transporter from the metal hyperaccumulator noccaea caerulescens confers enhanced zinc and cadmium tolerance and accumulation to arabidopsis thaliana

    NARCIS (Netherlands)

    Lin, Ya Fen; Hassan, Zeshan; Talukdar, S.; Schat, Henk; Aarts, Mark G.M.

    2016-01-01

    Prompt regulation of transition metal transporters is crucial for plant zinc homeostasis. NcZNT1 is one of such transporters, found in the metal hyperaccumulator Brassicaceae species Noccaea caerulescens. It is orthologous to AtZIP4 from Arabidopsis thaliana, an important actor in Zn homeostasis.

  17. Biomass production and carbohydrate content of Arabidopsis thaliana at atmospheric CO2 concentrations from 390 to 1680 mu l l(-1)

    NARCIS (Netherlands)

    Van der Kooij, TAW; De Kok, LJ; Stulen, I.

    1999-01-01

    The concentration dependency of the impact of elevated atmospheric CO2 concentrations on Arabidopsis thaliana L. was studied. Plants were exposed to nearly ambient (390), 560, 810, 1240 and 1680 mu l l(-1) CO2 during the vegetative growth phase for 8 days. Shoot biomass production and dry matter con

  18. Reproductive Toxicity and Life History Study of Silver Nanoparticle Effect, Uptake and Transport in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Jane Geisler-Lee

    2014-04-01

    Full Text Available Concerns about nanotechnology have prompted studies on how the release of these engineered nanoparticles impact our environment. Herein, the impact of 20 nm silver nanoparticles (AgNPs on the life history traits of Arabidopsis thaliana was studied in both above- and below-ground parts, at macroscopic and microscopic scales. Both gross phenotypes (in contrast to microscopic phenotypes and routes of transport and accumulation were investigated from roots to shoots. Wild type Arabidopsis growing in soil, regularly irrigated with 75 μg/L of AgNPs, did not show any obvious morphological change. However, their vegetative development was prolonged by two to three days and their reproductive growth shortened by three to four days. In addition, the germination rates of offspring decreased drastically over three generations. These findings confirmed that AgNPs induce abiotic stress and cause reproductive toxicity in Arabidopsis. To trace transport of AgNPs, this study also included an Arabidopsis reporter line genetically transformed with a green fluorescent protein and grown in an optical transparent medium with 75 μg/L AgNPs. AgNPs followed three routes: (1 At seven days after planting (DAP at S1.0 (stages defined by Boyes et al. 2001 [41], AgNPs attached to the surface of primary roots and then entered their root tips; (2 At 14 DAP at S1.04, as primary roots grew longer, AgNPs gradually moved into roots and entered new lateral root primordia and root hairs; (3 At 17 DAP at S1.06 when the Arabidopsis root system had developed multiple lateral roots, AgNPs were present in vascular tissue and throughout the whole plant from root to shoot. In some cases, if cotyledons of the Arabidopsis seedlings were immersed in melted transparent medium, then AgNPs were taken up by and accumulated in stomatal guard cells. These findings in Arabidopsis are the first to document specific routes and rates of AgNP uptake in vivo and in situ.

  19. The rapidly evolving centromere-specific histone has stringent functional requirements in Arabidopsis thaliana.

    Science.gov (United States)

    Ravi, Maruthachalam; Kwong, Pak N; Menorca, Ron M G; Valencia, Joel T; Ramahi, Joseph S; Stewart, Jodi L; Tran, Robert K; Sundaresan, Venkatesan; Comai, Luca; Chan, Simon W-L

    2010-10-01

    Centromeres control chromosome inheritance in eukaryotes, yet their DNA structure and primary sequence are hypervariable. Most animals and plants have megabases of tandem repeats at their centromeres, unlike yeast with unique centromere sequences. Centromere function requires the centromere-specific histone CENH3 (CENP-A in human), which replaces histone H3 in centromeric nucleosomes. CENH3 evolves rapidly, particularly in its N-terminal tail domain. A portion of the CENH3 histone-fold domain, the CENP-A targeting domain (CATD), has been previously shown to confer kinetochore localization and centromere function when swapped into human H3. Furthermore, CENP-A in human cells can be functionally replaced by CENH3 from distantly related organisms including Saccharomyces cerevisiae. We have used cenh3-1 (a null mutant in Arabidopsis thaliana) to replace endogenous CENH3 with GFP-tagged variants. A H3.3 tail domain-CENH3 histone-fold domain chimera rescued viability of cenh3-1, but CENH3's lacking a tail domain were nonfunctional. In contrast to human results, H3 containing the A. thaliana CATD cannot complement cenh3-1. GFP-CENH3 from the sister species A. arenosa functionally replaces A. thaliana CENH3. GFP-CENH3 from the close relative Brassica rapa was targeted to centromeres, but did not complement cenh3-1, indicating that kinetochore localization and centromere function can be uncoupled. We conclude that CENH3 function in A. thaliana, an organism with large tandem repeat centromeres, has stringent requirements for functional complementation in mitosis.

  20. Morphological, physiological and molecular genetic characterization ofArabidopsis himalaica, with reference toA. thaliana.

    Science.gov (United States)

    Tsukaya, H; Yokoyama, J; Ikeda, H; Kuroiwa, H; Kuroiwa, T; Iwatsuki, K

    1997-03-01

    Arabidopsis himalaica (Edgeworth) O.E. Schulz, a poorly characterized species typical of HimalayanArabidopsis, was analyzed in terms of its morphology, physiology, chromosome number and molecular genetics, in comparison withA. thaliana which is the standard species in the genusArabidopsis. From view point of developmental genetics, several features which are specific toA. himalaica seem not to be derived by single-gene mutations inA. thaliana. Phylogenetic analyses based onrbcL sequences suggested that genusArabidopsis is not monophyletic. The detailed characterization ofA. himalaica should provide clues to understand the trait of evolution of particular features of Himalayan species ofArabidopsis and their genetic basis.

  1. Apparent homology of expressed genes from wood-forming tissues of loblolly pine (Pinus taeda L.) with Arabidopsis thaliana.

    Science.gov (United States)

    Kirst, Matias; Johnson, Arthur F; Baucom, Christie; Ulrich, Erin; Hubbard, Kristy; Staggs, Rod; Paule, Charles; Retzel, Ernest; Whetten, Ross; Sederoff, Ronald

    2003-06-10

    Pinus taeda L. (loblolly pine) and Arabidopsis thaliana differ greatly in form, ecological niche, evolutionary history, and genome size. Arabidopsis is a small, herbaceous, annual dicotyledon, whereas pines are large, long-lived, coniferous forest trees. Such diverse plants might be expected to differ in a large number of functional genes. We have obtained and analyzed 59,797 expressed sequence tags (ESTs) from wood-forming tissues of loblolly pine and compared them to the gene sequences inferred from the complete sequence of the Arabidopsis genome. Approximately 50% of pine ESTs have no apparent homologs in Arabidopsis or any other angiosperm in public databases. When evaluated by using contigs containing long, high-quality sequences, we find a higher level of apparent homology between the inferred genes of these two species. For those contigs 1,100 bp or longer, approximately 90% have an apparent Arabidopsis homolog (E value < 10-10). Pines and Arabidopsis last shared a common ancestor approximately 300 million years ago. Few genes would be expected to retain high sequence similarity for this time if they did not have essential functions. These observations suggest substantial conservation of gene sequence in seed plants.

  2. The aba mutant of Arabidopsis thaliana is impaired in epoxy-carotenoid biosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Rock, C.D.; Zeevaart, J.A.D. (Michigan State Univ., East Lansing (United States))

    1991-09-01

    The three mutant alleles of the ABA locus of Arabidopsis thaliana result in plants that are deficient in the plant growth regulator abscisic acid (ABA). The authors have used {sup 18}O{sub 2} to label ABA in water-stressed leaves of mutant and wild-type Arabidopsis. Analysis by selected ion monitoring and tandem mass spectrometry of ({sup 18}O)ABA and its catabolites, phaseic acid and ABA-glucose ester ({beta}-D-glucopyranosyl abscisate), indicates that the aba genotypes are impaired in ABA biosynthesis and have a small ABA precursor pool of compounds that contain oxygens on the rings, presumably oxygenated carotenoids (xanthophylls). Quantitation of the carotenoids form mutant and wild-type leaves establishes that the aba alleles cause a deficiency of the epoxy-carotenoids violaxanthin and neoxanthin and an accumulation of their biosynthetic precursor, zeaxanthin. These results provide evidence that ABA is synthesized by oxidative cleavage of epoxy-carotenoids (the indirect pathway). Furthermore the carotenoid mutant they describe undergoes normal greening. Thus the aba alleles provide an opportunity to study the physiological roles of epoxy-carotenoids in photosynthesis in a higher plants.

  3. Fusarium oxysporum triggers tissue-specific transcriptional reprogramming in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Rebecca Lyons

    Full Text Available Some of the most devastating agricultural diseases are caused by root-infecting pathogens, yet the majority of studies on these interactions to date have focused on the host responses of aerial tissues rather than those belowground. Fusarium oxysporum is a root-infecting pathogen that causes wilt disease on several plant species including Arabidopsis thaliana. To investigate and compare transcriptional changes triggered by F. oxysporum in different Arabidopsis tissues, we infected soil-grown plants with F. oxysporum and subjected root and leaf tissue harvested at early and late timepoints to RNA-seq analyses. At least half of the genes induced or repressed by F. oxysporum showed tissue-specific regulation. Regulators of auxin and ABA signalling, mannose binding lectins and peroxidases showed strong differential expression in root tissue. We demonstrate that ARF2 and PRX33, two genes regulated in the roots, promote susceptibility to F. oxysporum. In the leaves, defensins and genes associated with the response to auxin, cold and senescence were strongly regulated while jasmonate biosynthesis and signalling genes were induced throughout the plant.

  4. Fusarium oxysporum triggers tissue-specific transcriptional reprogramming in Arabidopsis thaliana.

    Science.gov (United States)

    Lyons, Rebecca; Stiller, Jiri; Powell, Jonathan; Rusu, Anca; Manners, John M; Kazan, Kemal

    2015-01-01

    Some of the most devastating agricultural diseases are caused by root-infecting pathogens, yet the majority of studies on these interactions to date have focused on the host responses of aerial tissues rather than those belowground. Fusarium oxysporum is a root-infecting pathogen that causes wilt disease on several plant species including Arabidopsis thaliana. To investigate and compare transcriptional changes triggered by F. oxysporum in different Arabidopsis tissues, we infected soil-grown plants with F. oxysporum and subjected root and leaf tissue harvested at early and late timepoints to RNA-seq analyses. At least half of the genes induced or repressed by F. oxysporum showed tissue-specific regulation. Regulators of auxin and ABA signalling, mannose binding lectins and peroxidases showed strong differential expression in root tissue. We demonstrate that ARF2 and PRX33, two genes regulated in the roots, promote susceptibility to F. oxysporum. In the leaves, defensins and genes associated with the response to auxin, cold and senescence were strongly regulated while jasmonate biosynthesis and signalling genes were induced throughout the plant.

  5. Autophagy contributes to regulation of the hypoxia response during submergence in Arabidopsis thaliana.

    Science.gov (United States)

    Chen, Liang; Liao, Bin; Qi, Hua; Xie, Li-Juan; Huang, Li; Tan, Wei-Juan; Zhai, Ning; Yuan, Li-Bing; Zhou, Ying; Yu, Lu-Jun; Chen, Qin-Fang; Shu, Wensheng; Xiao, Shi

    2015-01-01

    Autophagy involves massive degradation of intracellular components and functions as a conserved system that helps cells to adapt to adverse conditions. In mammals, hypoxia rapidly stimulates autophagy as a cell survival response. Here, we examine the function of autophagy in the regulation of the plant response to submergence, an abiotic stress that leads to hypoxia and anaerobic respiration in plant cells. In Arabidopsis thaliana, submergence induces the transcription of autophagy-related (ATG) genes and the formation of autophagosomes. Consistent with this, the autophagy-defective (atg) mutants are hypersensitive to submergence stress and treatment with ethanol, the end product of anaerobic respiration. Upon submergence, the atg mutants have increased levels of transcripts of anaerobic respiration genes (alcohol dehydrogenase 1, ADH1 and pyruvate decarboxylase 1, PDC1), but reduced levels of transcripts of other hypoxia- and ethylene-responsive genes. Both submergence and ethanol treatments induce the accumulation of reactive oxygen species (ROS) in the rosettes of atg mutants more than in the wild type. Moreover, the production of ROS by the nicotinamide adenine dinucleotide phosphate (NADPH) oxidases is necessary for plant tolerance to submergence and ethanol, submergence-induced expression of ADH1 and PDC1, and activation of autophagy. The submergence- and ethanol-sensitive phenotypes in the atg mutants depend on a complete salicylic acid (SA) signaling pathway. Together, our findings demonstrate that submergence-induced autophagy functions in the hypoxia response in Arabidopsis by modulating SA-mediated cellular homeostasis.

  6. A collection of target mimics for comprehensive analysis of microRNA function in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Marco Todesco

    2010-07-01

    Full Text Available Many targets of plant microRNAs (miRNAs are thought to play important roles in plant physiology and development. However, because plant miRNAs are typically encoded by medium-size gene families, it has often been difficult to assess their precise function. We report the generation of a large-scale collection of knockdowns for Arabidopsis thaliana miRNA families; this has been achieved using artificial miRNA target mimics, a recently developed technique fashioned on an endogenous mechanism of miRNA regulation. Morphological defects in the aerial part were observed for approximately 20% of analyzed families, all of which are deeply conserved in land plants. In addition, we find that non-cleavable mimic sites can confer translational regulation in cis. Phenotypes of plants expressing target mimics directed against miRNAs involved in development were in several cases consistent with previous reports on plants expressing miRNA-resistant forms of individual target genes, indicating that a limited number of targets mediates most effects of these miRNAs. That less conserved miRNAs rarely had obvious effects on plant morphology suggests that most of them do not affect fundamental aspects of development. In addition to insight into modes of miRNA action, this study provides an important resource for the study of miRNA function in plants.

  7. Impacts of high ATP supply from chloroplasts and mitochondria on the leaf metabolism of Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Chao eLiang

    2015-10-01

    Full Text Available Chloroplasts and mitochondria are the major ATP producing organelles in plant leaves. Arabidopsis thaliana purple acid phosphatase 2 (AtPAP2 is a phosphatase dually targeted to the outer membranes of both organelles and it plays a role in the import of selected nuclear-encoded proteins into these two organelles. Overexpression (OE of AtPAP2 in Arabidopsis thaliana accelerates plant growth and promotes flowering, seed yield and biomass at maturity. Measurement of ADP/ATP/NADP+/NADPH contents in the leaves of 20-day-old OE and wild-type lines at the end of night and at 1 and 8 h following illumination in a 16/8 h photoperiod revealed that the ATP levels and ATP/NADPH ratios were significantly increased in the OE line at all three time points. The AtPAP2 OE line is therefore a good model to investigate the impact of high energy on the global molecular status of Arabidopsis. In this study, transcriptome, proteome and metabolome profiles of the high ATP transgenic line were examined and compared with those of wild-type plants. A comparison of OE and WT at the end of the night provide valuable information on the impact of higher ATP output from mitochondria on plant physiology, as mitochondrial respiration is the major source of ATP in the dark in leaves. Similarly, comparison of OE and WT following illumination will provide information on the impact of higher energy output from chloroplasts on plant physiology. Overexpression of AtPAP2 was found to significantly affect the transcript and protein abundances of genes encoded by the two organellar genomes. For example, the protein abundances of many ribosomal proteins encoded by the chloroplast genome were higher in the AtPAP2 OE line under both light and dark conditions, while the protein abundances of multiple components of the photosynthetic complexes were lower. RNA-seq data also showed that the transcription of the mitochondrial genome is greatly affected by the availability of energy. These data

  8. Linkage and association mapping of Arabidopsis thaliana flowering time in nature.

    Directory of Open Access Journals (Sweden)

    Benjamin Brachi

    2010-05-01

    Full Text Available Flowering time is a key life-history trait in the plant life cycle. Most studies to unravel the genetics of flowering time in Arabidopsis thaliana have been performed under greenhouse conditions. Here, we describe a study about the genetics of flowering time that differs from previous studies in two important ways: first, we measure flowering time in a more complex and ecologically realistic environment; and, second, we combine the advantages of genome-wide association (GWA and traditional linkage (QTL mapping. Our experiments involved phenotyping nearly 20,000 plants over 2 winters under field conditions, including 184 worldwide natural accessions genotyped for 216,509 SNPs and 4,366 RILs derived from 13 independent crosses chosen to maximize genetic and phenotypic diversity. Based on a photothermal time model, the flowering time variation scored in our field experiment was poorly correlated with the flowering time variation previously obtained under greenhouse conditions, reinforcing previous demonstrations of the importance of genotype by environment interactions in A. thaliana and the need to study adaptive variation under natural conditions. The use of 4,366 RILs provides great power for dissecting the genetic architecture of flowering time in A. thaliana under our specific field conditions. We describe more than 60 additive QTLs, all with relatively small to medium effects and organized in 5 major clusters. We show that QTL mapping increases our power to distinguish true from false associations in GWA mapping. QTL mapping also permits the identification of false negatives, that is, causative SNPs that are lost when applying GWA methods that control for population structure. Major genes underpinning flowering time in the greenhouse were not associated with flowering time in this study. Instead, we found a prevalence of genes involved in the regulation of the plant circadian clock. Furthermore, we identified new genomic regions lacking

  9. Arabidopsis thaliana CENTRORADIALIS homologue (ATC) acts systemically to inhibit floral initiation in Arabidopsis.

    Science.gov (United States)

    Huang, Nien-Chen; Jane, Wann-Neng; Chen, Jychian; Yu, Tien-Shin

    2012-10-01

    Floral initiation is orchestrated by systemic floral activators and inhibitors. This remote-control system may integrate environmental cues to modulate floral initiation. Recently, FLOWERING LOCUS T (FT) was found to be a florigen. However, the identity of systemic floral inhibitor or anti-florigen remains to be elucidated. Here we show that Arabidopsis thaliana CENTRORADIALIS homologue (ATC), an Arabidopsis FT homologue, may act in a non-cell autonomous manner to inhibit floral initiation. Analysis of the ATC null mutant revealed that ATC is a short-day-induced floral inhibitor. Cell type-specific expression showed that companion cells and apex that express ATC are sufficient to inhibit floral initiation. Histochemical analysis showed that the promoter activity of ATC was mainly found in vasculature but under the detection limit in apex, a finding that suggests that ATC may move from the vasculature to the apex to influence flowering. Consistent with this notion, Arabidopsis seedling grafting experiments demonstrated that ATC moved over a long distance and that floral inhibition by ATC is graft transmissible. ATC probably antagonizes FT activity, because both ATC and FT interact with FD and affect the same downstream meristem identity genes APETALA1, in an opposite manner. Thus, photoperiodic variations may trigger functionally opposite FT homologues to systemically influence floral initiation.

  10. Crystal Structure of Ll-Diaminopimelate Aminotransferase From 'Arabidopsis Thaliana': a Recently-Discovered Enzyme in the Biosynthesis of L-Lysine By Plants And 'Chlamydia'

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, N.; Cherney, M.M.; van Belkum, M.J.; Marcus, S.L.; Flegel, M.D.; Clay, M.D.; Deyholos, M.K.; Vederas, J.C.; James, M.N.G.

    2007-07-13

    The essential biosynthetic pathway to l-Lysine in bacteria and plants is an attractive target for the development of new antibiotics or herbicides because it is absent in humans, who must acquire this amino acid in their diet. Plants use a shortcut of a bacterial pathway to l-Lysine in which the pyridoxal-5-phosphate (PLP)-dependent enzyme ll-diaminopimelate aminotransferase (LL-DAP-AT) transforms l-tetrahydrodipicolinic acid (L-THDP) directly to LL-DAP. In addition, LL-DAP-AT was recently found in Chlamydia sp., suggesting that inhibitors of this enzyme may also be effective against such organisms. In order to understand the mechanism of this enzyme and to assist in the design of inhibitors, the three-dimensional crystal structure of LL-DAP-AT was determined at 1.95 Angstroms resolution. The cDNA sequence of LL-DAP-AT from Arabidopsis thaliana (AtDAP-AT) was optimized for expression in bacteria and cloned in Escherichia coli without its leader sequence but with a C-terminal hexahistidine affinity tag to aid protein purification. The structure of AtDAP-AT was determined using the multiple-wavelength anomalous dispersion (MAD) method with a seleno-methionine derivative. AtDAP-AT is active as a homodimer with each subunit having PLP in the active site. It belongs to the family of type I fold PLP-dependent enzymes. Comparison of the active site residues of AtDAP-AT and aspartate aminotransferases revealed that the PLP binding residues in AtDAP-AT are well conserved in both enzymes. However, Glu97* and Asn309* in the active site of AtDAP-AT are not found at similar positions in aspartate aminotransferases, suggesting that specific substrate recognition may require these residues from the other monomer. A malate-bound structure of AtDAP-AT allowed LL-DAP and L-glutamate to be modeled into the active site. These initial three-dimensional structures of LL-DAP-AT provide insight into its substrate specificity and catalytic mechanism.

  11. An antagonist of lipid A action in mammals has complex effects on lipid A induction of defence responses in the model plant Arabidopsis thaliana

    DEFF Research Database (Denmark)

    Erbs, Gitte; Jensen, Tina Tandrup; Silipo, Alba;

    2008-01-01

    Lipopolysaccharides, the ubiquitous part of the outer membrane of Gram-negative bacteria, and their derivatives are recognised by plants to trigger or potentiate particular defence responses such as induction of genes encoding pathogenesis-related proteins. The molecular mechanisms of LPS...... perception that underpin these effects in plants are, however, unknown. Here, lipid A from Halomonas magadiensis, which is an antagonist of lipid A action in human cells, was used to investigate lipid A action in plants. Our findings offer an insight into the different structural requirements for direct...

  12. Investigating the Association between Flowering Time and Defense in the Arabidopsis thaliana-Fusarium oxysporum Interaction.

    Science.gov (United States)

    Lyons, Rebecca; Rusu, Anca; Stiller, Jiri; Powell, Jonathan; Manners, John M; Kazan, Kemal

    2015-01-01

    Plants respond to pathogens either by investing more resources into immunity which is costly to development, or by accelerating reproductive processes such as flowering time to ensure reproduction occurs before the plant succumbs to disease. In this study we explored the link between flowering time and pathogen defense using the interaction between Arabidopsis thaliana and the root infecting fungal pathogen Fusarium oxysporum. We report that F. oxysporum infection accelerates flowering time and regulates transcription of a number of floral integrator genes, including FLOWERING LOCUS C (FLC), FLOWERING LOCUS T (FT) and GIGANTEA (GI). Furthermore, we observed a positive correlation between late flowering and resistance to F. oxysporum in A. thaliana natural ecotypes. Late-flowering gi and autonomous pathway mutants also exhibited enhanced resistance to F. oxysporum, supporting the association between flowering time and defense. However, epistasis analysis showed that accelerating flowering time by deletion of FLC in fve-3 or fpa-7 mutants did not alter disease resistance, suggesting that the effect of autonomous pathway on disease resistance occurs independently from flowering time. Indeed, RNA-seq analyses suggest that fve-3 mediated resistance to F. oxysporum is most likely a result of altered defense-associated gene transcription. Together, our results indicate that the association between flowering time and pathogen defense is complex and can involve both pleiotropic and direct effects.

  13. Crystal structure of glutamate-1-semialdehyde-2,1-aminomutase from Arabidopsis thaliana

    Energy Technology Data Exchange (ETDEWEB)

    Song, Yingxian; Pu, Hua; Jiang, Tian; Zhang, Lixin; Ouyang, Min, E-mail: ouyangmin@ibcas.ac.cn [Chinese Academy of Sciences, Beijing 100093, People’s Republic of (China)

    2016-05-23

    A structural study of A. thaliana glutamate-1-semialdehyde-2,1-aminomutase (GSAM) has revealed asymmetry in cofactor binding as well as in the gating-loop orientation, which supports the previously proposed negative cooperativity between monomers of GSAM. Glutamate-1-semialdehyde-2,1-aminomutase (GSAM) catalyzes the isomerization of glutamate-1-semialdehyde (GSA) to 5-aminolevulinate (ALA) and is distributed in archaea, most bacteria and plants. Although structures of GSAM from archaea and bacteria have been resolved, a GSAM structure from a higher plant is not available, preventing further structure–function analysis. Here, the structure of GSAM from Arabidopsis thaliana (AtGSA1) obtained by X-ray crystallography is reported at 1.25 Å resolution. AtGSA1 forms an asymmetric dimer and displays asymmetry in cofactor binding as well as in the gating-loop orientation, which is consistent with previously reported Synechococcus GSAM structures. While one monomer binds PMP with the gating loop fixed in the open state, the other monomer binds either PMP or PLP and the gating loop is ready to close. The data also reveal the mobility of residues Gly163, Ser164 and Gly165, which are important for reorientation of the gating loop. Furthermore, the asymmetry of the AtGSA1 structure supports the previously proposed negative cooperativity between monomers of GSAM.

  14. Century-scale methylome stability in a recently diverged Arabidopsis thaliana lineage.

    Directory of Open Access Journals (Sweden)

    Jörg Hagmann

    2015-01-01

    Full Text Available There has been much excitement about the possibility that exposure to specific environments can induce an ecological memory in the form of whole-sale, genome-wide epigenetic changes that are maintained over many generations. In the model plant Arabidopsis thaliana, numerous heritable DNA methylation differences have been identified in greenhouse-grown isogenic lines, but it remains unknown how natural, highly variable environments affect the rate and spectrum of such changes. Here we present detailed methylome analyses in a geographically dispersed A. thaliana population that constitutes a collection of near-isogenic lines, diverged for at least a century from a common ancestor. Methylome variation largely reflected genetic distance, and was in many aspects similar to that of lines raised in uniform conditions. Thus, even when plants are grown in varying and diverse natural sites, genome-wide epigenetic variation accumulates mostly in a clock-like manner, and epigenetic divergence thus parallels the pattern of genome-wide DNA sequence divergence.

  15. Induction of Nickel Accumulation in Response to Zinc Deficiency in Arabidopsis thaliana.

    Science.gov (United States)

    Nishida, Sho; Kato, Aki; Tsuzuki, Chisato; Yoshida, Junko; Mizuno, Takafumi

    2015-04-27

    Excessive accumulation of nickel (Ni) can be toxic to plants. In Arabidopsis thaliana, the Fe²⁺ transporter, iron (Fe)-regulated transporter1 (IRT1), mediates Fe uptake and also implicates in Ni²⁺ uptake at roots; however, the underlying mechanism of Ni²⁺ uptake and accumulation remains unelucidated. In the present study, we found that zinc (Zn) deficient conditions resulted in increased accumulation of Ni in plants, particularly in roots, in A. thaliana. In order to elucidate the underlying mechanisms of Ni uptake correlating zinc condition, we traced 63Ni isotope in response to Zn and found that (i) Zn deficiency induces short-term Ni²⁺ absorption and (ii) Zn²⁺ inhibits Ni²⁺ uptake, suggesting competitive uptake between Ni and Zn. Furthermore, the Zrt/Irt-like protein 3 (ZIP3)-defective mutant with an elevated Zn-deficient response exhibited higher Ni accumulation than the wild type, further supporting that the response to Zn deficiency induces Ni accumulation. Previously, expression profile study demonstrated that IRT1 expression is not inducible by Zn deficiency. In the present study, we found increased Ni accumulation in IRT1-null mutant under Zn deficiency in agar culture. These suggest that Zn deficiency induces Ni accumulation in an IRT1-independen manner. The present study revealed that Ni accumulation is inducible in response to Zn deficiency, which may be attributable to a Zn uptake transporter induced by Zn deficiency.

  16. Diurnal changes in shoot water dynamics are synchronized with hypocotyl elongation in Arabidopsis thaliana

    Science.gov (United States)

    Ishikawa, Haruki; Sato-Nara, Kumi; Takase, Tomoyuki; Suzuki, Hitoshi

    2013-01-01

    We recently demonstrated the circadian clock modulated water dynamics in the roots of a small model plant, Arabidopsis thaliana, by the Nuclear Magnetic Resonance (NMR) microimaging technique. Our developed technique was able to visualize the water distribution that depended on differences in the 1H signal among region in the shoot, such as the shoot apex, the hypocotyl and the root shoot junction. Water content in the shoot increased during periods of light in comparison with dark periods, and continued through the early stage of seedling growth until the dark period. When the water content changed, elongation and/or movement occurred in the hypocotyl, and these events were synchronized. The water dynamics of the shoot also displayed an opposite phase with the root water dynamics. PMID:23299330

  17. Germline-transmitted genome editing in Arabidopsis thaliana Using TAL-effector-nucleases.

    Directory of Open Access Journals (Sweden)

    Joachim Forner

    Full Text Available Transcription activator-like effector nucleases (TALENs are custom-made bi-partite endonucleases that have recently been developed and applied for genome engineering in a wide variety of organisms. However, they have been only scarcely used in plants, especially for germline-modification. Here we report the efficient creation of small, germline-transmitted deletions in Arabidopsis thaliana via TALENs that were delivered by stably integrated transgenes. Using meristem specific promoters to drive expression of two TALEN arms directed at the CLV3 coding sequence, we observed very high phenotype frequencies in the T2 generation. In some instances, full CLV3 loss-of-function was already observed in the T1 generation, suggesting that transgenic delivery of TALENs can cause highly efficient genome modification. In contrast, constitutive TALEN expression in the shoot apical meristem (SAM did not cause additional phenotypes and genome re-sequencing confirmed little off-target effects, demonstrating exquisite target specificity.

  18. Germline-transmitted genome editing in Arabidopsis thaliana Using TAL-effector-nucleases.

    Science.gov (United States)

    Forner, Joachim; Pfeiffer, Anne; Langenecker, Tobias; Manavella, Pablo A; Manavella, Pablo; Lohmann, Jan U

    2015-01-01

    Transcription activator-like effector nucleases (TALENs) are custom-made bi-partite endonucleases that have recently been developed and applied for genome engineering in a wide variety of organisms. However, they have been only scarcely used in plants, especially for germline-modification. Here we report the efficient creation of small, germline-transmitted deletions in Arabidopsis thaliana via TALENs that were delivered by stably integrated transgenes. Using meristem specific promoters to drive expression of two TALEN arms directed at the CLV3 coding sequence, we observed very high phenotype frequencies in the T2 generation. In some instances, full CLV3 loss-of-function was already observed in the T1 generation, suggesting that transgenic delivery of TALENs can cause highly efficient genome modification. In contrast, constitutive TALEN expression in the shoot apical meristem (SAM) did not cause additional phenotypes and genome re-sequencing confirmed little off-target effects, demonstrating exquisite target specificity.

  19. An Arabidopsis thaliana high-affinity molybdate transporter required for efficient uptake of molybdate from soil.

    Science.gov (United States)

    Tomatsu, Hajime; Takano, Junpei; Takahashi, Hideki; Watanabe-Takahashi, Akiko; Shibagaki, Nakako; Fujiwara, Toru

    2007-11-20

    Molybdenum (Mo) is a trace element essential for living organisms, however no molybdate transporter has been identified in eukaryotes. Here, we report the identification of a molybdate transporter, MOT1, from Arabidopsis thaliana. MOT1 is expressed in both roots and shoots, and the MOT1 protein is localized, in part, to plasma membranes and to vesicles. MOT1 is required for efficient uptake and translocation of molybdate and for normal growth under conditions of limited molybdate supply. Kinetics studies in yeast revealed that the K(m) value of MOT1 for molybdate is approximately 20 nM. Furthermore, Mo uptake by MOT1 in yeast was not affected by coexistent sulfate, and MOT1 did not complement a sulfate transporter-deficient yeast mutant strain. These data confirmed that MOT1 is specific for molybdate and that the high affinity of MOT1 allows plants to obtain scarce Mo from soil.

  20. Natural variations in expression of regulatory and detoxification related genes under limiting phosphate and arsenate stress in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Tapsi eShukla

    2015-10-01

    Full Text Available Abiotic stress including nutrient deficiency and heavy metal toxicity severely affects plant growth, development, and productivity. Genetic variations within and in between species are one of the important factors in establishing interactions and responses of plants with the environment. In the recent past, natural variations in Arabidopsis thaliana have been used to understand plant development and response towards different stresses at genetic level. Phosphorus (Pi deficiency negatively affects plant growth and metabolism and modulates expression of the genes involved in Pi homeostasis. Arsenate, As(V, a chemical analogue of Pi, is taken up by the plants via phosphate transport system. Studies suggest that during Pi deficiency, enhanced As(V uptake leads to increased toxicity in plants. Here, the natural variations in Arabidopsis have been utilized to study the As(V stress response under limiting Pi condition. The primary root length was compared to identify differential response of three Arabidopsis accessions (Col-0, Sij-1 and Slavi-1 under limiting Pi and As(V stress. To study the molecular mechanisms responsible for the differential response, comprehensive expression profiling of the genes involved in uptake, detoxification and regulatory mechanisms was carried out. Analysis suggests genetic variation-dependent regulatory mechanisms may affect differential response of Arabidopsis natural variants towards As(V stress under limiting Pi condition. Therefore, it is hypothesized that detailed analysis of the natural variations under multiple stress conditions might help in the better understanding of the biological processes involved in stress tolerance and adaptation.

  1. Yeast cell wall extract induces disease resistance against bacterial and fungal pathogens in Arabidopsis thaliana and Brassica crop.

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    Mari Narusaka

    Full Text Available Housaku Monogatari (HM is a plant activator prepared from a yeast cell wall extract. We examined the efficacy of HM application and observed that HM treatment increased the resistance of Arabidopsis thaliana and Brassica rapa leaves to bacterial and fungal infections. HM reduced the severity of bacterial leaf spot and anthracnose on A. thaliana and Brassica crop leaves with protective effects. In addition, gene expression analysis of A. thaliana plants after treatment with HM indicated increased expression of several plant defense-related genes. HM treatment appears to induce early activation of jasmonate/ethylene and late activation of salicylic acid (SA pathways. Analysis using signaling mutants revealed that HM required SA accumulation and SA signaling to facilitate resistance to the bacterial pathogen Pseudomonas syringae pv. maculicola and the fungal pathogen Colletotrichum higginsianum. In addition, HM-induced resistance conferred chitin-independent disease resistance to bacterial pathogens in A. thaliana. These results suggest that HM contains multiple microbe-associated molecular patterns that activate defense responses in plants. These findings suggest that the application of HM is a useful tool that may facilitate new disease control methods.

  2. Polycomb-group (Pc-G) Proteins Control Seed Development in Arabidopsis thaliana L.

    Institute of Scientific and Technical Information of China (English)

    Xiao-Xue Wang; Li-Geng Ma

    2007-01-01

    Polycomb-group (Pc-G) proteins repress their target gene expression by assemble complexes in Drosophila and mammals. Three groups of Pc-G genes, controlling seed development, flower development and vernalization response, have been identified in Arabidopsis (Arabidopsis thaliana L.). MEDEA (MEA), FERTIL IZA TION INDEPENDENT SEED2 (FIS2), and FERTILIZATION INDEPENDENT ENDOSPERM (FIE) are Pc-G genes in Arabidopsis. Their functions in seed development have been extensively explored. The advanced findings of molecular mechanism on how MEA, FIS2 and FIE control seed development in Arabidopsis are reviewed in this paper.

  3. Changes in homologous recombination frequency in Arabidopsis thaliana plants exposed to stress depend on time of exposure during development and on duration of stress exposure.

    Science.gov (United States)

    Rahavi, Seyed Mohammad Reza; Kovalchuk, Igor

    2013-10-01

    In the past, we showed that exposure to abiotic and biotic stresses changes the homologous recombination frequency (HRF) in somatic tissue and in the progeny. In current work we planned to answer the following question: do stress intensity/duration and time during exposure influence changes in somatic HRF and transgenerational changes in HRF? Here, we tested the effects of exposure to UV-C, cold and heat on HRF at 7, 14, 21 and 28 days post germination (dpg). We found that exposure at 14 and 21 dpg resulted in a higher increase in HRF as compared to exposure at 7 dpg; longer exposure to UV-C resulted in a higher frequency of HR, whereas prolonged exposure to cold or heat, especially at later developmental stages, had almost no effect on somatic HRF. Exposure at 7 dpg had a positive effect on somatic growth of plants; plants exposed to stress at this age had larger leaves. The analysis of HRF in the progeny showed that the progeny of plants exposed to stress at 7 dpg had an increase in somatic HRF and showed larger sizes of recombination spots on leaves. The progeny of plants exposed to UV-C at 7 dpg and the progeny of plants exposed to cold or heat at 28 dpg had larger leaves as compared to control plants. To summarize, our experiments showed that changes in somatic and transgenerational HRF depend on the type of stress plants are exposed to, time of exposure during development and the duration of exposure.

  4. Metabolome analysis of Arabidopsis thaliana roots identifies a key metabolic pathway for iron acquisition.

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    Holger Schmidt

    Full Text Available Fe deficiency compromises both human health and plant productivity. Thus, it is important to understand plant Fe acquisition strategies for the development of crop plants which are more Fe-efficient under Fe-limited conditions, such as alkaline soils, and have higher Fe density in their edible tissues. Root secretion of phenolic compounds has long been hypothesized to be a component of the reduction strategy of Fe acquisition in non-graminaceous plants. We therefore subjected roots of Arabidopsis thaliana plants grown under Fe-replete and Fe-deplete conditions to comprehensive metabolome analysis by gas chromatography-mass spectrometry and ultra-pressure liquid chromatography electrospray ionization quadrupole time-of-flight mass spectrometry. Scopoletin and other coumarins were found among the metabolites showing the strongest response to two different Fe-limited conditions, the cultivation in Fe-free medium and in medium with an alkaline pH. A coumarin biosynthesis mutant defective in ortho-hydroxylation of cinnamic acids was unable to grow on alkaline soil in the absence of Fe fertilization. Co-cultivation with wild-type plants partially rescued the Fe deficiency phenotype indicating a contribution of extracellular coumarins to Fe solubilization. Indeed, coumarins were detected in root exudates of wild-type plants. Direct infusion mass spectrometry as well as UV/vis spectroscopy indicated that coumarins are acting both as reductants of Fe(III and as ligands of Fe(II.

  5. Isolation of intact and pure chloroplasts from leaves of Arabidopsis thaliana plants acclimated to low irradiance for studies on Rubisco regulation

    Directory of Open Access Journals (Sweden)

    Magda Grabsztunowicz

    2012-11-01

    Full Text Available A protocol is presented for low-cost and fast isolation of intact and pure chloroplasts from leaves of plants acclimated to low irradiance. The protocol is based on a differential centrifugation of cleared leaf homogenate and omits a centrifugation on Percoll gradient step. The intactness and purity of the chloroplasts isolated from leaves of low irradiance-acclimated plants by using this protocol (confirmed by phase contrast microscopy as well as enzymatic and immunological approaches allows plausible studies on low irradiance-dependent Rubisco regulation.

  6. Genome-scale cold stress response regulatory networks in ten Arabidopsis thaliana ecotypes

    DEFF Research Database (Denmark)

    Barah, Pankaj; Jayavelu, Naresh Doni; Rasmussen, Simon

    2013-01-01

    BACKGROUND: Low temperature leads to major crop losses every year. Although several studies have been conducted focusing on diversity of cold tolerance level in multiple phenotypically divergent Arabidopsis thaliana (A. thaliana) ecotypes, genome-scale molecular understanding is still lacking...... using Arabidopsis NimbleGen ATH6 microarrays. In total 6061 transcripts were significantly cold regulated (p majority of the transcripts (75%) showed ecotype specific expression pattern. By using sequence data...... available from Arabidopsis thaliana 1001 genome project, we further investigated sequence polymorphisms in the core cold stress regulon genes. Significant numbers of non-synonymous amino acid changes were observed in the coding region of the CBF regulon genes. Considering the limited knowledge about...

  7. Transformation of Arabidopsis thaliana via Agrobacterium tumefacience with an endochitinase gene from Trichoderma, and enhanced resistance to Sclerotinia sclerotiorum

    Institute of Scientific and Technical Information of China (English)

    DAI Fu-ming; XU Tong

    2004-01-01

    @@ Sclerotinia sclerotiorum is an important pathogen to many crops and is especially damaging to rape in China. As a model plant Arabidopsis thaliana (ColO) was transformed by spraying Agrobacterium tumefacience with Trichoderma endochitinase gene ThEn-42 at initial bud stage. Eleven seedlings (corresponding to about 0.22 percent transformation) exhibited resistance to hygromycin. The DNA fragment unique to endochitinase ( ThEn-42 ) was amplified by Arabidopsis leaf-PCR or genomic DNA PCR. Unfertile, dwarf and normal phenotypes appeared in the T1 generation. In addition, an enhanced resistance to S. sclerotiorum was observed. The mortality percentage (7.7% to 33.3%) in transgenic plants was significantly lower than in non-transgenic plants (86. 7%) 10 days after inoculation with the pathogen.

  8. Fibonacci spirals in a brown alga [Sargassum muticum (Yendo Fensholt] and in a land plant [Arabidopsis thaliana (L. Heynh.]: a case of morphogenetic convergence

    Directory of Open Access Journals (Sweden)

    Alexis Peaucelle

    2016-12-01

    Full Text Available In this article, the morphology of a brown alga is revisited and compared to the phyllotaxis of land plants. The alga, Sargassum muticum (Yendo Fensholt has a highly organized thallus with a stipe, the stem-like main axis, and hierarchically organized lateral branches of successive orders. Around each of these axes, the lateral organs: blades, side-branches, and receptacles grow in a spiral disposition. As in land plants, this organization is related to an apical mode of growth. Measurements performed along the mature differentiated axes as well as in their meristematic regions confirm the similarity of the large-scale organization of this brown alga with that of the land plants. In particular, the divergence angle between successive elements has similar values and it results from the existence around the meristem of parastichies having the same Fibonacci ordering. This is remarkable in view of the fact that brown algae (Phaeophyceae and land plants (Embryophyta are two clades that diverged approximately 1800 million years ago when they were both unicellular organisms. We argue that the observed similarity results from a morphogenetic convergence. This is in strong support of the genericity and robustness of self-organization models in which similar structures, here Fibonacci related spirals, can be obtained in various situations in which the genetic and physiological implementation of development can be of a different nature.

  9. Enhancing pterin and para-aminobenzoate content is not sufficient to successfully biofortify potato tubers and Arabidopsis thaliana plants with folate

    NARCIS (Netherlands)

    Blancquaert, D.; Storozhenko, S.; Daele, W.; Stove, C.; Visser, R.G.F.; Lambert, W.; Straeten, van der D.

    2013-01-01

    Folates are important cofactors in one-carbon metabolism in all living organisms. Since only plants and micro- organisms are capable of biosynthesizing folates, humans depend entirely on their diet as a folate source. Given the low folate content of several staple crop products, folate deficiency af

  10. In Silico Analysis of Arabidopsis thaliana Peroxisomal 6-Phosphogluconate Dehydrogenase

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    Álvaro D. Fernández-Fernández

    2016-01-01

    Full Text Available NADPH, whose regeneration is critical for reductive biosynthesis and detoxification pathways, is an essential component in cell redox homeostasis. Peroxisomes are subcellular organelles with a complex biochemical machinery involved in signaling and stress processes by molecules such as hydrogen peroxide (H2O2 and nitric oxide (NO. NADPH is required by several peroxisomal enzymes involved in β-oxidation, NO, and glutathione (GSH generation. Plants have various NADPH-generating dehydrogenases, one of which is 6-phosphogluconate dehydrogenase (6PGDH. Arabidopsis contains three 6PGDH genes that probably are encoded for cytosolic, chloroplastic/mitochondrial, and peroxisomal isozymes, although their specific functions remain largely unknown. This study focuses on the in silico analysis of the biochemical characteristics and gene expression of peroxisomal 6PGDH (p6PGDH with the aim of understanding its potential function in the peroxisomal NADPH-recycling system. The data show that a group of plant 6PGDHs contains an archetypal type 1 peroxisomal targeting signal (PTS, while in silico gene expression analysis using affymetrix microarray data suggests that Arabidopsis p6PGDH appears to be mainly involved in xenobiotic response, growth, and developmental processes.

  11. The Opuntia streptacantha OpsHSP18 Gene Confers Salt and Osmotic Stress Tolerance in Arabidopsis thaliana

    Science.gov (United States)

    Salas-Muñoz, Silvia; Gómez-Anduro, Gracia; Delgado-Sánchez, Pablo; Rodríguez-Kessler, Margarita; Jiménez-Bremont, Juan Francisco

    2012-01-01

    Abiotic stress limits seed germination, plant growth, flowering and fruit quality, causing economic decrease. Small Heat Shock Proteins (sHSPs) are chaperons with roles in stress tolerance. Herein, we report the functional characterization of a cytosolic class CI sHSP (OpsHSP18) from Opuntia streptacantha during seed germination in Arabidopsis thaliana transgenic lines subjected to different stress and hormone treatments. The over-expression of the OpsHSP18 gene in A. thaliana increased the seed germination rate under salt (NaCl) and osmotic (glucose and mannitol) stress, and in ABA treatments, compared with WT. On the other hand, the over-expression of the OpsHSP18 gene enhanced tolerance to salt (150 mM NaCl) and osmotic (274 mM mannitol) stress in Arabidopsis seedlings treated during 14 and 21 days, respectively. These plants showed increased survival rates (52.00 and 73.33%, respectively) with respect to the WT (18.75 and 53.75%, respectively). Thus, our results show that OpsHSP18 gene might have an important role in abiotic stress tolerance, in particular in seed germination and survival rate of Arabidopsis plants under unfavorable conditions. PMID:22949853

  12. Proteomic and phosphoproteomic analyses of chromatin-associated proteins from Arabidopsis thaliana

    KAUST Repository

    Bigeard, Jean

    2014-07-10

    The nucleus is the organelle where basically all DNA-related processes take place in eukaryotes, such as replication, transcription, and splicing as well as epigenetic regulation. The identification and description of the nuclear proteins is one of the requisites toward a comprehensive understanding of the biological functions accomplished in the nucleus. Many of the regulatory mechanisms of protein functions rely on their PTMs among which phosphorylation is probably one of the most important properties affecting enzymatic activity, interaction with other molecules, localization, or stability. So far, the nuclear and subnuclear proteome and phosphoproteome of the model plant Arabidopsis thaliana have been the subject of very few studies. In this work, we developed a purification protocol of Arabidopsis chromatin-associated proteins and performed proteomic and phosphoproteomic analyses identifying a total of 879 proteins of which 198 were phosphoproteins that were mainly involved in chromatin remodeling, transcriptional regulation, and RNA processing. From 230 precisely localized phosphorylation sites (phosphosites), 52 correspond to hitherto unidentified sites. This protocol and data thereby obtained should be a valuable resource for many domains of plant research.

  13. Dynamic Acclimation to High Light in Arabidopsis thaliana Involves Widespread Reengineering of the Leaf Proteome

    Directory of Open Access Journals (Sweden)

    Matthew A. E. Miller

    2017-07-01

    Full Text Available Leaves of Arabidopsis thaliana transferred from low to high light increase their capacity for photosynthesis, a process of dynamic acclimation. A mutant, gpt2, lacking a chloroplast glucose-6-phosphate/phosphate translocator, is deficient in its ability to acclimate to increased light. Here, we have used a label-free proteomics approach, to perform relative quantitation of 1993 proteins from Arabidopsis wild type and gpt2 leaves exposed to increased light. Data are available via ProteomeXchange with identifier PXD006598. Acclimation to light is shown to involve increases in electron transport and carbon metabolism but no change in the abundance of photosynthetic reaction centers. The gpt2 mutant shows a similar increase in total protein content to wild type but differences in the extent of change of certain proteins, including in the relative abundance of the cytochrome b6f complex and plastocyanin, the thylakoid ATPase and selected Benson-Calvin cycle enzymes. Changes in leaf metabolite content as plants acclimate can be explained by changes in the abundance of enzymes involved in metabolism, which were reduced in gpt2 in some cases. Plants of gpt2 invest more in stress-related proteins, suggesting that their reduced ability to acclimate photosynthetic capacity results in increased stress.

  14. Arabidopsis thaliana WAPL is essential for the prophase removal of cohesin during meiosis.

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    Kuntal De

    2014-07-01

    Full Text Available Sister chromatid cohesion, which is mediated by the cohesin complex, is essential for the proper segregation of chromosomes in mitosis and meiosis. The establishment of stable sister chromatid cohesion occurs during DNA replication and involves acetylation of the complex by the acetyltransferase CTF7. In higher eukaryotes, the majority of cohesin complexes are removed from chromosomes during prophase. Studies in fly and human have shown that this process involves the WAPL mediated opening of the cohesin ring at the junction between the SMC3 ATPase domain and the N-terminal domain of cohesin's α-kleisin subunit. We report here the isolation and detailed characterization of WAPL in Arabidopsis thaliana. We show that Arabidopsis contains two WAPL genes, which share overlapping functions. Plants in which both WAPL genes contain T-DNA insertions show relatively normal growth and development but exhibit a significant reduction in male and female fertility. The removal of cohesin from chromosomes during meiotic prophase is blocked in Atwapl mutants resulting in chromosome bridges, broken chromosomes and uneven chromosome segregation. In contrast, while subtle mitotic alterations are observed in some somatic cells, cohesin complexes appear to be removed normally. Finally, we show that mutations in AtWAPL suppress the lethality associated with inactivation of AtCTF7. Taken together our results demonstrate that WAPL plays a critical role in meiosis and raises the possibility that mechanisms involved in the prophase removal of cohesin may vary between mitosis and meiosis in plants.

  15. Parabolic flight induces changes in gene expression patterns in Arabidopsis thaliana.

    Science.gov (United States)

    Paul, Anna-Lisa; Manak, Michael S; Mayfield, John D; Reyes, Matthew F; Gurley, William B; Ferl, Robert J

    2011-10-01

    Our primary objective was to evaluate gene expression changes in Arabidopsis thaliana in response to parabolic flight as part of a comprehensive approach to the molecular biology of spaceflight-related adaptations. In addition, we wished to establish parabolic flight as a tractable operations platform for molecular biology studies. In a succession of experiments on NASA's KC-135 and C-9 parabolic aircraft, Arabidopsis plants were presented with replicated exposure to parabolic flight. Transcriptome profiling revealed that parabolic flight caused changes in gene expression patterns that stood the statistical tests of replication on three different flight days. The earliest response, after 20 parabolas, was characterized by a prominence of genes associated with signal transduction. After 40 parabolas, this prominence was largely replaced by genes associated with biotic and abiotic stimuli and stress. Among these responses, three metabolic processes stand out in particular: the induction of auxin metabolism and signaling, the differential expression of genes associated with calcium-mediated signaling, and the repression of genes associated with disease resistance and cell wall biochemistry. Many, but not all, of these responses are known to be involved in gravity sensing in plants. Changes in auxin-related gene expression were also recorded by reporter genes tuned to auxin signal pathways. These data demonstrate that the parabolic flight environment is appropriate for molecular biology research involving the transition to microgravity, in that with replication, proper controls, and analyses, gene expression changes can be observed in the time frames of typical parabolic flight experiments.

  16. Transcriptomic Profiling Analysis of Arabidopsis thaliana Treated with Exogenous Myo-Inositol

    Science.gov (United States)

    Ye, Wenxing; Ren, Weibo; Kong, Lingqi; Zhang, Wanjun; Wang, Tao

    2016-01-01

    Myo-insositol (MI) is a crucial substance in the growth and developmental processes in plants. It is commonly added to the culture medium to promote adventitious shoot development. In our previous work, MI was found in influencing Agrobacterium-mediated transformation. In this report, a high-throughput RNA sequencing technique (RNA-Seq) was used to investigate differently expressed genes in one-month-old Arabidopsis seedling grown on MI free or MI supplemented culture medium. The results showed that 21,288 and 21,299 genes were detected with and without MI treatment, respectively. The detected genes included 184 new genes that were not annotated in the Arabidopsis thaliana reference genome. Additionally, 183 differentially expressed genes were identified (DEGs, FDR ≤0.05, log2 FC≥1), including 93 up-regulated genes and 90 down-regulated genes. The DEGs were involved in multiple pathways, such as cell wall biosynthesis, biotic and abiotic stress response, chromosome modification, and substrate transportation. Some significantly differently expressed genes provided us with valuable information for exploring the functions of exogenous MI. RNA-Seq results showed that exogenous MI could alter gene expression and signaling transduction in plant cells. These results provided a systematic understanding of the functions of exogenous MI in detail and provided a foundation for future studies. PMID:27603208

  17. Characterisation of the first enzymes committed to lysine biosynthesis in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Michael D W Griffin

    Full Text Available In plants, the lysine biosynthetic pathway is an attractive target for both the development of herbicides and increasing the nutritional value of crops given that lysine is a limiting amino acid in cereals. Dihydrodipicolinate synthase (DHDPS and dihydrodipicolinate reductase (DHDPR catalyse the first two committed steps of lysine biosynthesis. Here, we carry out for the first time a comprehensive characterisation of the structure and activity of both DHDPS and DHDPR from Arabidopsis thaliana. The A. thaliana DHDPS enzyme (At-DHDPS2 has similar activity to the bacterial form of the enzyme, but is more strongly allosterically inhibited by (S-lysine. Structural studies of At-DHDPS2 show (S-lysine bound at a cleft between two monomers, highlighting the allosteric site; however, unlike previous studies, binding is not accompanied by conformational changes, suggesting that binding may cause changes in protein dynamics rather than large conformation changes. DHDPR from A. thaliana (At-DHDPR2 has similar specificity for both NADH and NADPH during catalysis, and has tighter binding of substrate than has previously been reported. While all known bacterial DHDPR enzymes have a tetrameric structure, analytical ultracentrifugation, and scattering data unequivocally show that At-DHDPR2 exists as a dimer in solution. The exact arrangement of the dimeric protein is as yet unknown, but ab initio modelling of x-ray scattering data is consistent with an elongated structure in solution, which does not correspond to any of the possible dimeric pairings observed in the X-ray crystal structure of DHDPR from other organisms. This increased knowledge of the structure and function of plant lysine biosynthetic enzymes will aid future work aimed at improving primary production.

  18. Ecotype dependent expression and alternative splicing of epithiospecifier protein (ESP) in Arabidopsis thaliana.

    Science.gov (United States)

    Kissen, R; Hyldbakk, E; Wang, C-W V; Sørmo, C G; Rossiter, J T; Bones, A M

    2012-03-01

    Epithiospecifier protein (ESP) is responsible for diverting glucosinolate hydrolysis from the generation of isothiocyanates to that of epithionitriles or nitriles, and thereby negatively affects the ability of the plant to defend itself against certain insects. Despite this important role of ESP, little is known about its expression in plant tissues and the regulation thereof. We therefore investigated ESP expression by qPCR and Western blot in different organs during the growth cycle of the two Arabidopsis thaliana ecotypes Col-0 and Mt-0. Besides the fact that ESP transcript and protein levels were revealed to be much higher in Mt-0 than in Col-0 in all cases, our qPCR results also indicated that ESP expression is regulated differently in the two A. thaliana ecotypes. No ESP protein was detected by Western blot in any organ or developmental stage for Col-0. During the assays an alternative splice variant of ESP was identified in Col-0, but not Mt-0, leading to a mis-spliced transcript which could explain the low expression levels of ESP in the former ecotype. Analysis of genomic sequences containing the ESP splice sites, of ESP protein level and ESP activity from seven A. thaliana ecotypes showed a positive correlation between the presence of a non-canonical 5' splice site for ESP and the absence of detectable ESP protein levels and ESP activity. When analysing the expression of both transcript variants in Col-0 after treatment with methyl jasmonate, a condition known to "induce ESP", it was indeed the alternative splice variant that was preferentially induced.

  19. Titanium dioxide nanoparticles (100-1000 mg/l) can affect vitamin E response in Arabidopsis thaliana.

    Science.gov (United States)

    Szymańska, Renata; Kołodziej, Karolina; Ślesak, Ireneusz; Zimak-Piekarczyk, Paulina; Orzechowska, Aleksandra; Gabruk, Michał; Żądło, Andrzej; Habina, Iwona; Knap, Wiesław; Burda, Květoslava; Kruk, Jerzy

    2016-06-01

    In the present study we analyze the effect of seed treatment by a range of nano-TiO2 concentrations on the growth of Arabidopsis thaliana plants, on the vitamin E content and the expression of its biosynthetic genes, as well as activity of antioxidant enzymes and lipid peroxidation. To conduct the mechanistic analysis of nano-TiO2 on plants growth and antioxidant status we applied nanoparticles concentrations that are much higher than those reported in the environment. We find that as the concentration of nano-TiO2 increases, the biomass, and chlorophyll content in 5-week-old Arabidopsis thaliana plants decrease in a concentration dependent manner. In opposite, higher nano-TiO2 concentration enhanced root growth. Our results indicate that a high concentration of nano-TiO2 induces symptoms of toxicity and elevates the antioxidant level. We also find that the expression levels of tocopherol biosynthetic genes were either down- or upregulated in response to nano-TiO2. Thermoluminescence analysis shows that higher nano-TiO2 concentrations cause lipid peroxidation. To the best of our knowledge, this is the first report concerning the effect of nano-TiO2 on vitamin E status in plants. We conclude that nano-TiO2 affects the antioxidant response in Arabidopsis thaliana plants. This could be an effect of a changes in vitamin E gene expression that is diminished under lower tested nano-TiO2 concentrations and elevated under 1000 μg/ml.

  20. LEA (Late Embryogenesis Abundant proteins and their encoding genes in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Hincha Dirk K

    2008-03-01

    Full Text Available Abstract Background LEA (late embryogenesis abundant proteins have first been described about 25 years ago as accumulating late in plant seed development. They were later found in vegetative plant tissues following environmental stress and also in desiccation tolerant bacteria and invertebrates. Although they are widely assumed to play crucial roles in cellular dehydration tolerance, their physiological and biochemical functions are largely unknown. Results We present a genome-wide analysis of LEA proteins and their encoding genes in Arabidopsis thaliana. We identified 51 LEA protein encoding genes in the Arabidopsis genome that could be classified into nine distinct groups. Expression studies were performed on all genes at different developmental stages, in different plant organs and under different stress and hormone treatments using quantitative RT-PCR. We found evidence of expression for all 51 genes. There was only little overlap between genes expressed in vegetative tissues and in seeds and expression levels were generally higher in seeds. Most genes encoding LEA proteins had abscisic acid response (ABRE and/or low temperature response (LTRE elements in their promoters and many genes containing the respective promoter elements were induced by abscisic acid, cold or drought. We also found that 33% of all Arabidopsis LEA protein encoding genes are arranged in tandem repeats and that 43% are part of homeologous pairs. The majority of LEA proteins were predicted to be highly hydrophilic and natively unstructured, but some were predicted to be folded. Conclusion The analyses indicate a wide range of sequence diversity, intracellular localizations, and expression patterns. The high fraction of retained duplicate genes and the inferred functional diversification indicate that they confer an evolutionary advantage for an organism under varying stressful environmental conditions. This comprehensive analysis will be an important starting point for

  1. EFFECT OF SEED XYLOGLUCANS AND DERIVATES ON THE GROWTH OF Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Adriana Tourinho Salamoni

    2009-10-01

    Full Text Available Studies on xyloglucan (XG extracted from Hymenaea courbaril L. (jatoba seeds showed that this biopolymer has biological activity that enhanced wheat coleoptiles growth. In apple tree micropropagation, the culture medium containing XG combined with agar induced a higher multiplication rate, rooting rate and root length than medium solidified with agar only. The purpose of this study was to determine the effect of XG from jatobá seeds extracted from jatoba seeds collected in Sinope/MT (XGS and Cuiabá/MT (XGC, and from XGC hydrolysed with a cellulase (XGCH, as well from Tamarindus indica seeds (XGT collected in Bahia/BA, on the growth of in vitro cultured Arabidopsis thaliana plantlets. In the first experiment, XGCH (0.25, 25 and 250 nM or XGC (0.5, 50 and 500 nM were added to a liquid half-strength MS medium. In the second experiment, XGs from several origins were compared: XGC (500 nM, XGS (1200 nM and XGT (800 nM, using culture medium solidified with 6 g.L-1agar. Arabidopsis thaliana L. seeds germinated in Petri plates for 4 to 5 days were transferred to culture media containing the different concentrations of XGs and cultured in a growing room. When the plantlets were cultured in a liquid medium, their growth was very slow in the presence of XGC and XGCH at the highest concentration tested, and it was faster at the lowest concentration. In the semi-solid culture medium, XGs also reduced growth. It was concluded that XGs can play a biological role in Arabidopsis thaliana (L. Heynh. plantlets, stimulating or inhibiting the root system growth and the lateral root formation. These opposite effects varied according to the plant specie that furnished the seeds containing XG, as well as the place where the seeds were collected, to the XG form used (hydrolyzed or not and to its concentration in the culture media. 

  2. Yeast Methylotrophy and Autophagy in a Methanol-Oscillating Environment on Growing Arabidopsis thaliana Leaves

    OpenAIRE

    Kosuke Kawaguchi; Hiroya Yurimoto; Masahide Oku; Yasuyoshi Sakai

    2011-01-01

    The yeast Candida boidinii capable of growth on methanol proliferates and survives on the leaves of Arabidopsis thaliana. The local methanol concentration at the phyllosphere of growing A. thaliana exhibited daily periodicity, and yeast cells responded by altering both the expression of methanol-inducible genes and peroxisome proliferation. Even under these dynamically changing environmental conditions, yeast cells proliferated 3 to 4 times in 11 days. Among the C1-metabolic enzymes, enzymes ...

  3. The hidden geometries of the Arabidopsis thaliana epidermis.

    Directory of Open Access Journals (Sweden)

    Lee Staff

    Full Text Available The quest for the discovery of mathematical principles that underlie biological phenomena is ancient and ongoing. We present a geometric analysis of the complex interdigitated pavement cells in the Arabidopsis thaliana (Col. adaxial epidermis with a view to discovering some geometric characteristics that may govern the formation of this tissue. More than 2,400 pavement cells from 10, 17 and 24 day old leaves were analyzed. These interdigitated cells revealed a number of geometric properties that remained constant across the three age groups. In particular, the number of digits per cell rarely exceeded 15, irrespective of cell area. Digit numbers per 100 µm(2 cell area reduce with age and as cell area increases, suggesting early developmental programming of digits. Cell shape proportions as defined by length:width ratios were highly conserved over time independent of the size and, interestingly, both the mean and the medians were close to the golden ratio 1.618034. With maturity, the cell area:perimeter ratios increased from a mean of 2.0 to 2.4. Shape properties as defined by the medial axis transform (MAT were calculated and revealed that branch points along the MAT typically comprise one large and two small angles. These showed consistency across the developmental stages considered here at 140° (± 5° for the largest angles and 110° (± 5° for the smaller angles. Voronoi diagram analyses of stomatal center coordinates revealed that giant pavement cells (≥ 500 µm(2 tend to be arranged along Voronoi boundaries suggesting that they could function as a scaffold of the epidermis. In addition, we propose that pavement cells have a role in spacing and positioning of the stomata in the growing leaf and that they do so by growing within the limits of a set of 'geometrical rules'.

  4. A New Anti-Aging Lysophosphatidic Acid from Arabidopsis thaliana.

    Science.gov (United States)

    Sun, Yujuan; Wang, Yanhui; Wang, Guangfa; Xiang, Lan; Qi, Jianhua

    2017-02-09

    Aging is a risk factor of age-related diseases. With the increasing number of patients, serious consequences, and heavy economic burden, demands for drugs used to treat age-related diseases have increased. As such, anti-aging substances should be isolated to develop drugs for the prevention and treatment of age-related diseases. In this study, a methanol extract of immature Arabidopsis thaliana seeds with coat was separated by using a K6001 yeast bioassay system. In order to investigate the action mechanism, four mutants, namely, Δuth1, Δskn7, Δsod1, and Δsod2 with K6001 background were employed and the anti-oxidative stress assay was performed. One new anti-aging lysophosphatidic acid (LPA) was obtained, and its structural and stereochemical characteristics were elucidated through spectroscopy and chemical derivatization. LPA can extend the replicative lifespan of K6001 at 10 and 30 µM (p < 0.001 and p < 0.01, respectively). This finding was comparable to the effect of resveratrol, a well-known anti-aging substance. However, the anti-aging activity of the compound on the four mutants was diminished. In the anti-oxidative stress assay, LPA improved the oxidative resistance of yeast cells. The new LPA may exert its anti-aging effect by improving the anti-oxidative ability of yeast cells. The genes of UTH1, SKN7, and SOD may also be involved in the action. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  5. The Hidden Geometries of the Arabidopsis thaliana Epidermis

    KAUST Repository

    Staff, Lee

    2012-09-11

    The quest for the discovery of mathematical principles that underlie biological phenomena is ancient and ongoing. We present a geometric analysis of the complex interdigitated pavement cells in the Arabidopsis thaliana (Col.) adaxial epidermis with a view to discovering some geometric characteristics that may govern the formation of this tissue. More than 2,400 pavement cells from 10, 17 and 24 day old leaves were analyzed. These interdigitated cells revealed a number of geometric properties that remained constant across the three age groups. In particular, the number of digits per cell rarely exceeded 15, irrespective of cell area. Digit numbers per 100 ?m2 cell area reduce with age and as cell area increases, suggesting early developmental programming of digits. Cell shape proportions as defined by length:width ratios were highly conserved over time independent of the size and, interestingly, both the mean and the medians were close to the golden ratio 1.618034. With maturity, the cell area:perimeter ratios increased from a mean of 2.0 to 2.4. Shape properties as defined by the medial axis transform (MAT) were calculated and revealed that branch points along the MAT typically comprise one large and two small angles. These showed consistency across the developmental stages considered here at 140° (± 5°) for the largest angles and 110° (± 5°) for the smaller angles. Voronoi diagram analyses of stomatal center coordinates revealed that giant pavement cells (?500 ?m2) tend to be arranged along Voronoi boundaries suggesting that they could function as a scaffold of the epidermis. In addition, we propose that pavement cells have a role in spacing and positioning of the stomata in the growing leaf and that they do so by growing within the limits of a set of \\'geometrical rules\\'. © 2012 Staff et al.

  6. Acclimation increases freezing stress response of Arabidopsis thaliana at proteome level

    KAUST Repository

    Fanucchi, Francesca

    2012-06-01

    This study used 2DE to investigate how Arabidopsis thaliana modulates protein levels in response to freezing stress after sub-lethal exposure at - 10 °C, both in cold-acclimated and in non-acclimated plants. A map was implemented in which 62 spots, corresponding to 44 proteins, were identified. Twenty-two spots were modulated upon treatments, and the corresponding proteins proved to be related to photosynthesis, energy metabolism, and stress response. Proteins demonstrated differences between control and acclimation conditions. Most of the acclimation-responsive proteins were either not further modulated or they were down-modulated by freezing treatment, indicating that the levels reached during acclimation were sufficient to deal with freezing. Anabolic metabolism appeared to be down-regulated in favor of catabolic metabolism. Acclimated plants and plants submitted to freezing after acclimation showed greater reciprocal similarity in protein profiles than either showed when compared both to control plants and to plants frozen without acclimation. The response of non-acclimated plants was aimed at re-modulating photosynthetic apparatus activity, and at increasing the levels of proteins with antioxidant-, molecular chaperone-, or post-transcriptional regulative functions. These changes, even less effective than the acclimation strategy, might allow the injured plastids to minimize the production of non-useful metabolites and might counteract photosynthetic apparatus injuries. © 2012 Elsevier B.V. All rights reserved.

  7. Biodiversity of mineral nutrient and trace element accumulation in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Ivan Baxter

    Full Text Available In order to grow on soils that vary widely in chemical composition, plants have evolved mechanisms for regulating the elemental composition of their tissues to balance the mineral nutrient and trace element bioavailability in the soil with the requirements of the plant for growth and development. The biodiversity that exists within a species can be utilized to investigate how regulatory mechanisms of individual elements interact and to identify genes important for these processes. We analyzed the elemental composition (ionome of a set of 96 wild accessions of the genetic model plant Arabidopsis thaliana grown in hydroponic culture and soil using inductively coupled plasma mass spectrometry (ICP-MS. The concentrations of 17-19 elements were analyzed in roots and leaves from plants grown hydroponically, and leaves and seeds from plants grown in artificial soil. Significant genetic effects were detected for almost every element analyzed. We observed very few correlations between the elemental composition of the leaves and either the roots or seeds. There were many pairs of elements that were significantly correlated with each other within a tissue, but almost none of these pairs were consistently correlated across tissues and growth conditions, a phenomenon observed in several previous studies. These results suggest that the ionome of a plant tissue is variable, yet tightly controlled by genes and gene × environment interactions. The dataset provides a valuable resource for mapping studies to identify genes regulating elemental accumulation. All of the ionomic data is available at www.ionomicshub.org.

  8. Uptake and conversion of D-amino acids in Arabidopsis thaliana.

    Science.gov (United States)

    Gördes, Dirk; Kolukisaoglu, Üner; Thurow, Kerstin

    2011-02-01

    The D-enantiomers of proteinogenic amino acids fulfill essential functions in bacteria, fungi and animals. Just in the plant kingdom, the metabolism and role of D-amino acids (D-AAs) still remains unclear, although plants have to cope with significant amounts of these compounds from microbial decay in the rhizosphere. To fill this gap of knowledge, we tested the inhibitory effects of D-AAs on plant growth and established a method to quantitate 16 out of 19 proteinogenic amino acids and their D-enantiomers in plant tissue extracts. Therefore, the amino acids in the extracts were derivatized with Marfey's reagent and separated by HPLC-MS. We used two ecotypes (Col-0 and C24) and a mutant (lht1) of the model plant Arabidopsis thaliana to determine the influence and fate of exogenously applied D-AAs. All of them were found in high concentrations in the plant extracts after application, even in lht1, which points to additional transporters facilitating the import of D-AAs. The addition of particular amino acids (D-Trp, D-Phe, D-Met and D-His) led to the accumulation of the corresponding L-amino acid. In almost all cases, the application of a D-AA resulted in the accumulation of D-Ala and D-Glu. The presented results indicate that soil borne D-AAs can actively be taken up and metabolized via central metabolic routes.

  9. Crystallization of DIR1, a LTP2-like resistance signalling protein from Arabidopsis thaliana

    Energy Technology Data Exchange (ETDEWEB)

    Lascombe, Marie-Bernard, E-mail: marie-bernard.lascombe@univ-paris5.fr [UMR 8015 CNRS, Faculté de Pharmacie, 4 Avenue de l’Observatoire, 75006 Paris (France); Buhot, Nathalie [John Innes Centre, Norwich NR4 7UH (United Kingdom); Bakan, Bénédicte; Marion, Didier [Unité de Recherches Biopolymères, Interactions, Assemblages, INRA, La Géraudière, BP 71627 (France); Blein, Jean Pierre [Phytopharmacie et Biochimie des Interactions Cellulaires, UMR 692 CNRS, INRA, BP 86510, Dijon CEDEX (France); Lamb, Chris J. [John Innes Centre, Norwich NR4 7UH (United Kingdom); Prangé, Thierry [UMR 8015 CNRS, Faculté de Pharmacie, 4 Avenue de l’Observatoire, 75006 Paris (France)

    2006-07-01

    DIR1, a putative LTP2 protein from Arabidopsis thaliana implicated in systemic acquired resistance in planta, has been crystallized in space group P2{sub 1}2{sub 1}2{sub 1} with one molecule per asymmetric unit. DIR1, a putative LTP2 protein from Arabidopsis thaliana implicated in systemic acquired resistance in planta, has been crystallized in space group P2{sub 1}2{sub 1}2{sub 1} with one molecule per asymmetric unit. The crystals diffract to a resolution of 1.6 Å.

  10. Genome-scale cold stress response regulatory networks in ten Arabidopsis thaliana ecotypes

    DEFF Research Database (Denmark)

    Barah, Pankaj; Jayavelu, Naresh Doni; Rasmussen, Simon

    2013-01-01

    BACKGROUND: Low temperature leads to major crop losses every year. Although several studies have been conducted focusing on diversity of cold tolerance level in multiple phenotypically divergent Arabidopsis thaliana (A. thaliana) ecotypes, genome-scale molecular understanding is still lacking...... using Arabidopsis NimbleGen ATH6 microarrays. In total 6061 transcripts were significantly cold regulated (p ... be crucial for their local geographic adaptation to cold temperature. Additionally, since the approach presented here is general, it could be adapted to study networks regulating biological process in any biological systems....

  11. DRB2 is required for microRNA biogenesis in Arabidopsis thaliana.

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    Andrew L Eamens

    Full Text Available BACKGROUND: The Arabidopsis thaliana (Arabidopsis DOUBLE-STRANDED RNA BINDING (DRB protein family consists of five members, DRB1 to DRB5. The biogenesis of two developmentally important small RNA (sRNA species, the microRNAs (miRNAs and trans-acting small interfering RNAs (tasiRNAs by DICER-LIKE (DCL endonucleases requires the assistance of DRB1 and DRB4 respectively. The importance of miRNA-directed target gene expression in plant development is exemplified by the phenotypic consequence of loss of DRB1 activity (drb1 plants. PRINCIPAL FINDINGS: Here we report that the developmental phenotype of the drb235 triple mutant plant is the result of deregulated miRNA biogenesis in the shoot apical meristem (SAM region. The expression of DRB2, DRB3 and DRB5 in wild-type seedlings is restricted to the SAM region. Small RNA sequencing of the corresponding tissue of drb235 plants revealed altered miRNA accumulation. Approximately half of the miRNAs detected remained at levels equivalent to those of wild-type plants. However, the accumulation of the remaining miRNAs was either elevated or reduced in the triple mutant. Examination of different single and multiple drb mutants revealed a clear association between the loss of DRB2 activity and altered accumulation for both the elevated and reduced miRNA classes. Furthermore, we show that the constitutive over-expression of DRB2 outside of its wild-type expression domain can compensate for the loss of DRB1 activity in drb1 plants. CONCLUSIONS/SIGNIFICANCE: Our results suggest that in the SAM region, DRB2 is both antagonistic and synergistic to the role of DRB1 in miRNA biogenesis, adding an additional layer of gene regulatory complexity in this developmentally important tissue.

  12. A small intergenic region drives exclusive tissue-specific expression of the adjacent genes in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Valle Estela M

    2009-10-01

    Full Text Available Abstract Background Transcription initiation by RNA polymerase II is unidirectional from most genes. In plants, divergent genes, defined as non-overlapping genes organized head-to-head, are highly represented in the Arabidopsis genome. Nevertheless, there is scarce evidence on functional analyses of these intergenic regions. The At5g06290 and At5g06280 loci are head-to-head oriented and encode a chloroplast-located 2-Cys peroxiredoxin B (2CPB and a protein of unknown function (PUF, respectively. The 2-Cys peroxiredoxins are proteins involved in redox processes, they are part of the plant antioxidant defence and also act as chaperons. In this study, the transcriptional activity of a small intergenic region (351 bp shared by At5g06290 and At5g06280 in Arabidopsis thaliana was characterized. Results Activity of the intergenic region in both orientations was analyzed by driving the β-glucuronidase (GUS reporter gene during the development and growth of Arabidopsis plants under physiological and stressful conditions. Results have shown that this region drives expression either of 2cpb or puf in photosynthetic or vascular tissues, respectively. GUS expression driven by the promoter in 2cpb orientation was enhanced by heat stress. On the other hand, the promoter in both orientations has shown similar down-regulation of GUS expression under low temperatures and other stress conditions such as mannitol, oxidative stress, or fungal elicitor. Conclusion The results from this study account for the first evidence of an intergenic region that, in opposite orientation, directs GUS expression in different spatially-localized Arabidopsis tissues in a mutually exclusive manner. Additionally, this is the first demonstration of a small intergenic region that drives expression of a gene whose product is involved in the chloroplast antioxidant defence such as 2cpb. Furthermore, these results contribute to show that 2cpb is related to the heat stress defensive system

  13. Structural and Functional Characterization of the Protein Kinase Mps1 in Arabidopsis thaliana

    Science.gov (United States)

    de Oliveira, Eduardo Alves Gamosa; Romeiro, Nelilma Correia; Ribeiro, Elane da Silva; Santa-Catarina, Claudete; Oliveira, Antônia Elenir Amâncio; Silveira, Vanildo; de Souza Filho, Gonçalo Apolinário; Venancio, Thiago Motta; Cruz, Marco Antônio Lopes

    2012-01-01

    In eukaryotes, protein kinases catalyze the transfer of a gamma-phosphate from ATP (or GTP) to specific amino acids in protein targets. In plants, protein kinases have been shown to participate in signaling cascades driving responses to environmental stimuli and developmental processes. Plant meristems are undifferentiated tissues that provide the major source of cells that will form organs throughout development. However, non-dividing specialized cells can also dedifferentiate and re-initiate cell division if exposed to appropriate conditions. Mps1 (Monopolar spindle) is a dual-specificity protein kinase that plays a critical role in monitoring the accuracy of chromosome segregation in the mitotic checkpoint mechanism. Although Mps1 functions have been clearly demonstrated in animals and fungi, its role in plants is so far unclear. Here, using structural and biochemical analyses here we show that Mps1 has highly similar homologs in many plant genomes across distinct lineages (e.g. AtMps1 in Arabidopsis thaliana). Several structural features (i.e. catalytic site, DFG motif and threonine triad) are clearly conserved in plant Mps1 kinases. Structural and sequence analysis also suggest that AtMps1 interact with other cell cycle proteins, such as Mad2 and MAPK1. By using a very specific Mps1 inhibitor (SP600125) we show that compromised AtMps1 activity hampers the development of A. thaliana seedlings in a dose-dependent manner, especially in secondary roots. Moreover, concomitant administration of the auxin IAA neutralizes the AtMps1 inhibition phenotype, allowing secondary root development. These observations let us to hypothesize that AtMps1 might be a downstream regulator of IAA signaling in the formation of secondary roots. Our results indicate that Mps1 might be a universal component of the Spindle Assembly Checkpoint machinery across very distant lineages of eukaryotes. PMID:23049844

  14. Structural and functional characterization of the protein kinase Mps1 in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Eduardo Alves Gamosa de Oliveira

    Full Text Available In eukaryotes, protein kinases catalyze the transfer of a gamma-phosphate from ATP (or GTP to specific amino acids in protein targets. In plants, protein kinases have been shown to participate in signaling cascades driving responses to environmental stimuli and developmental processes. Plant meristems are undifferentiated tissues that provide the major source of cells that will form organs throughout development. However, non-dividing specialized cells can also dedifferentiate and re-initiate cell division if exposed to appropriate conditions. Mps1 (Monopolar spindle is a dual-specificity protein kinase that plays a critical role in monitoring the accuracy of chromosome segregation in the mitotic checkpoint mechanism. Although Mps1 functions have been clearly demonstrated in animals and fungi, its role in plants is so far unclear. Here, using structural and biochemical analyses here we show that Mps1 has highly similar homologs in many plant genomes across distinct lineages (e.g. AtMps1 in Arabidopsis thaliana. Several structural features (i.e. catalytic site, DFG motif and threonine triad are clearly conserved in plant Mps1 kinases. Structural and sequence analysis also suggest that AtMps1 interact with other cell cycle proteins, such as Mad2 and MAPK1. By using a very specific Mps1 inhibitor (SP600125 we show that compromised AtMps1 activity hampers the development of A. thaliana seedlings in a dose-dependent manner, especially in secondary roots. Moreover, concomitant administration of the auxin IAA neutralizes the AtMps1 inhibition phenotype, allowing secondary root development. These observations let us to hypothesize that AtMps1 might be a downstream regulator of IAA signaling in the formation of secondary roots. Our results indicate that Mps1 might be a universal component of the Spindle Assembly Checkpoint machinery across very distant lineages of eukaryotes.

  15. Higher peroxidase activity, leaf nutrient contents and carbon isotope composition changes in Arabidopsis thaliana are related to rutin stress.

    Science.gov (United States)

    Hussain, M Iftikhar; Reigosa, Manuel J

    2014-09-15

    Rutin, a plant secondary metabolite that is used in cosmetics and food additive and has known medicinal properties, protects plants from UV-B radiation and diseases. Rutin has been suggested to have potential in weed management, but its mode of action at physiological level is unknown. Here, we report the biochemical, physiological and oxidative response of Arabidopsis thaliana to rutin at micromolar concentrations. It was found that fresh weight; leaf mineral contents (nitrogen, sodium, potassium, copper and aluminum) were decreased following 1 week exposure to rutin. Arabidopsis roots generate significant amounts of reactive oxygen species after rutin treatment, consequently increasing membrane lipid peroxidation, decreasing leaf Ca(2+), Mg(2+), Zn(2+), Fe(2+) contents and losing root viability. Carbon isotope composition in A. thaliana leaves was less negative after rutin application than the control. Carbon isotope discrimination values were decreased following rutin treatment, with the highest reduction compared to the control at 750μM rutin. Rutin also inhibited the ratio of CO2 from leaf to air (ci/ca) at all concentrations. Total protein contents in A. thaliana leaves were decreased following rutin treatment. It was concluded carbon isotope discrimination coincided with protein degradation, increase lipid peroxidation and a decrease in ci/ca values may be the primary action site of rutin. The present results suggest that rutin possesses allelopathic potential and could be used as a candidate to develop environment friendly natural herbicide.

  16. Genetic architecture of natural variation of telomere length in Arabidopsis thaliana.

    Science.gov (United States)

    Fulcher, Nick; Teubenbacher, Astrid; Kerdaffrec, Envel; Farlow, Ashley; Nordborg, Magnus; Riha, Karel

    2015-02-01

    Telomeres represent the repetitive sequences that cap chromosome ends and are essential for their protection. Telomere length is known to be highly heritable and is derived from a homeostatic balance between telomeric lengthening and shortening activities. Specific loci that form the genetic framework underlying telomere length homeostasis, however, are not well understood. To investigate the extent of natural variation of telomere length in Arabidopsis thaliana, we examined 229 worldwide accessions by terminal restriction fragment analysis. The results showed a wide range of telomere lengths that are specific to individual accessions. To identify loci that are responsible for this variation, we adopted a quantitative trait loci (QTL) mapping approach with multiple recombinant inbred line (RIL) populations. A doubled haploid RIL population was first produced using centromere-mediated genome elimination between accessions with long (Pro-0) and intermediate (Col-0) telomere lengths. Composite interval mapping analysis of this population along with two established RIL populations (Ler-2/Cvi-0 and Est-1/Col-0) revealed a number of shared and unique QTL. QTL detected in the Ler-2/Cvi-0 population were examined using near isogenic lines that confirmed causative regions on chromosomes 1 and 2. In conclusion, this work describes the extent of natural variation of telomere length in A. thaliana, identifies a network of QTL that influence telomere length homeostasis, examines telomere length dynamics in plants with hybrid backgrounds, and shows the effects of two identified regions on telomere length regulation.

  17. Abscisic acid induces ectopic outgrowth in epidermal cells through cortical microtubule reorganization in Arabidopsis thaliana

    Science.gov (United States)

    Takatani, Shogo; Hirayama, Takashi; Hashimoto, Takashi; Takahashi, Taku; Motose, Hiroyasu

    2015-01-01

    Abscisic acid (ABA) regulates seed maturation, germination and various stress responses in plants. The roles of ABA in cellular growth and morphogenesis, however, remain to be explored. Here, we report that ABA induces the ectopic outgrowth of epidermal cells in Arabidopsis thaliana. Seedlings of A. thaliana germinated and grown in the presence of ABA developed ectopic protrusions in the epidermal cells of hypocotyls, petioles and cotyledons. One protrusion was formed in the middle of each epidermal cell. In the hypocotyl epidermis, two types of cell files are arranged alternately into non-stoma cell files and stoma cell files, ectopic protrusions being restricted to the non-stoma cell files. This suggests the presence of a difference in the degree of sensitivity to ABA or in the capacity of cells to form protrusions between the two cell files. The ectopic outgrowth was suppressed in ABA insensitive mutants, whereas it was enhanced in ABA hypersensitive mutants. Interestingly, ABA-induced ectopic outgrowth was also suppressed in mutants in which microtubule organization was compromised. Furthermore, cortical microtubules were disorganized and depolymerized by the ABA treatment. These results suggest that ABA signaling induces ectopic outgrowth in epidermal cells through microtubule reorganization. PMID:26068445

  18. Quantification of camalexin, a phytoalexin from Arabidopsis thaliana: a comparison of five analytical methods.

    Science.gov (United States)

    Beets, Caryn; Dubery, Ian

    2011-12-15

    Camalexin is a phytoalexin of Arabidopsis thaliana and an important component of inducible defenses. Accurate quantification of low concentrations suffers from interference by structurally related metabolites. A. thaliana plants were induced with silver nitrate and camalexin was extracted using methanol and identified and quantified by (i) TLC as a blue fluorescent band, (ii) microtiter plate-based fluorescence spectroscopy, (iii) GC on a midpolar column coupled to flame ionization detection, (iv) C(18) HPLC coupled to a photodiode detector, and (v) UPLC coupled to a mass spectrometer detector. Standard curves over the range of 0.1-15 μg ml(-1) gave R(2) values from 0.996 to 0.999. The different methods were compared and evaluated for their ability to detect and quantify increasing concentrations (qualitative technique for the identification of camalexin and fluorescence spectroscopy is subject to quenching when performed on crude extracts. Comparable results were obtained with GC-FID, HPLC-PDA, and UPLC-MS, with UPLC-MS having the added advantage of short analysis times and detection based on accurate mass.

  19. Signaling Role of Fructose Mediated by FINS1/FBP in Arabidopsis thaliana

    Science.gov (United States)

    Cho, Young-Hee; Yoo, Sang-Dong

    2011-01-01

    Sugars are evolutionarily conserved signaling molecules that regulate the growth and development of both unicellular and multicellular organisms. As sugar-producing photosynthetic organisms, plants utilize glucose as one of their major signaling molecules. However, the details of other sugar signaling molecules and their regulatory factors have remained elusive, due to the complexity of the metabolite and hormone interactions that control physiological and developmental programs in plants. We combined information from a gain-of-function cell-based screen and a loss-of-function reverse-genetic analysis to demonstrate that fructose acts as a signaling molecule in Arabidopsis thaliana. Fructose signaling induced seedling developmental arrest and interacted with plant stress hormone signaling in a manner similar to that of glucose. For fructose signaling responses, the plant glucose sensor HEXOKINASE1 (HXK1) was dispensable, while FRUCTOSE INSENSITIVE1 (FINS1), a putative FRUCTOSE-1,6-BISPHOSPHATASE, played a crucial role. Interestingly, FINS1 function in fructose signaling appeared to be independent of its catalytic activity in sugar metabolism. Genetic analysis further indicated that FINS1–dependent fructose signaling may act downstream of the abscisic acid pathway, in spite of the fact that HXK1–dependent glucose signaling works upstream of hormone synthesis. Our findings revealed that multiple layers of controls by fructose, glucose, and abscisic acid finely tune the plant autotrophic transition and modulate early seedling establishment after seed germination. PMID:21253566

  20. Characterization of an Arabidopsis thaliana mutant lacking a cytosolic non-phosphorylating glyceraldehyde-3-phosphate dehydrogenase.

    Science.gov (United States)

    Rius, Sebastián P; Casati, Paula; Iglesias, Alberto A; Gomez-Casati, Diego F

    2006-08-01

    Non-phosphorylating glyceraldehyde- 3-phosphate dehydrogenase (NP-GAPDH) is a conserved cytosolic protein found in higher plants. In photosynthetic cells, the enzyme is involved in a shuttle transfer mechanism to export NADPH from the chloroplast to the cytosol. To investigate the role of this enzyme in plant tissues, we characterized a mutant from Arabidopsis thaliana having an insertion at the NP-GAPDH gene locus. The homozygous mutant was determined to be null respect to NP-GAPDH, as it exhibited undetectable levels of both transcription of NP-GAPDH mRNA, protein expression and enzyme activity. Transcriptome analysis demonstrated that the insertion mutant plant shows altered expression of several enzymes involved in carbohydrate metabolism. Significantly, cytosolic phosphorylating (NAD-dependent) glyceraldehyde-3-phosphate dehydrogenase mRNA levels are induced in the mutant, which correlates with an increase in enzyme activity. mRNA levels and enzymatic activity of glucose-6-phosphate dehydrogenase were also elevated, correlating with an increase in NADPH concentration. Moreover, increased ROS levels were measured in the mutant plants. Down-regulation of several glycolytic and photosynthetic genes suggests that NP-GAPDH is important for the efficiency of both metabolic processes. The results presented demonstrate that NP-GAPDH has a relevant role in plant growth and development.

  1. ROP GTPase-mediated auxin signaling regulates pavement cell interdigitation in Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    Deshu Lin; Huibo Ren; Ying Fu

    2015-01-01

    In multicel ular plant organs, cel shape formation depends on molecular switches to transduce developmental or environmental signals and to coordinate cel‐to‐cel communi-cation. Plants have a specific subfamily of the Rho GTPase family, usual y cal ed Rho of Plants (ROP), which serve as a critical signal transducer involved in many cel ular processes. In the last decade, important advances in the ROP‐mediated regulation of plant cel morphogenesis have been made by using Arabidopsis thaliana leaf and cotyledon pavement cel s. Especial y, the auxin‐ROP signaling networks have been demonstrated to control interdigitated growth of pavement cel s to form jigsaw‐puzzle shapes. Here, we review findings related to the discovery of this novel auxin‐signaling mecha-nism at the cel surface. This signaling pathway is to a large extent independent of the wel‐known Transport Inhibitor Response (TIR)–Auxin Signaling F‐Box (AFB) pathway, and instead requires Auxin Binding Protein 1 (ABP1) interaction with the plasma membrane‐localized, transmembrane kinase (TMK) receptor‐like kinase to regulate ROP proteins. Once activated, ROP influences cytoskeletal organization and inhibits endocytosis of the auxin transporter PIN1. The present review focuses on ROP signaling and its self‐organizing feature al owing ROP proteins to serve as a bustling signal decoder and integrator for plant cel morphogenesis.

  2. Investigation of the effect of phosphogypsum amendment on two Arabidopsis thaliana ecotype growth and development.

    Science.gov (United States)

    Ayadi, Amal; Chorriba, Amal; Fourati, Amine; Gargouri-Bouzid, Radhia

    2015-01-01

    The production of phosphoric acid from nat