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Sample records for arabidopsis thaliana flowering

  1. Reduction of mineral nutrient availability accelerates flowering of Arabidopsis thaliana

    Czech Academy of Sciences Publication Activity Database

    Kolář, Jan; Seňková, J.

    2008-01-01

    Roč. 165, č. 15 (2008), s. 1601-1609. ISSN 0176-1617 R&D Projects: GA AV ČR KJB600380510 Institutional research plan: CEZ:AV0Z50380511 Keywords : Arabidopsis thaliana * Flowering * Landsberg erecta Subject RIV: EF - Botanics Impact factor: 2.437, year: 2008

  2. Gibberellic acid signaling is required for ambient temperature-mediated induction of flowering in Arabidopsis thaliana.

    Science.gov (United States)

    Galvão, Vinicius Costa; Collani, Silvio; Horrer, Daniel; Schmid, Markus

    2015-12-01

    Distinct molecular mechanisms integrate changes in ambient temperature into the genetic pathways that govern flowering time in Arabidopsis thaliana. Temperature-dependent eviction of the histone variant H2A.Z from nucleosomes has been suggested to facilitate the expression of FT by PIF4 at elevated ambient temperatures. Here we show that, in addition to PIF4, PIF3 and PIF5, but not PIF1 and PIF6, can promote flowering when expressed specifically in phloem companion cells (PCC), where they can induce FT and its close paralog, TSF. However, despite their strong potential to promote flowering, genetic analyses suggest that the PIF genes seem to have only a minor role in adjusting flowering in response to photoperiod or high ambient temperature. In addition, loss of PIF function only partially suppressed the early flowering phenotype and FT expression of the arp6 mutant, which is defective in H2A.Z deposition. In contrast, the chemical inhibition of gibberellic acid (GA) biosynthesis resulted in a strong attenuation of early flowering and FT expression in arp6. Furthermore, GA was able to induce flowering at low temperature (15°C) independently of FT, TSF, and the PIF genes, probably directly at the shoot apical meristem. Together, our results suggest that the timing of the floral transition in response to ambient temperature is more complex than previously thought and that GA signaling might play a crucial role in this process. PMID:26466761

  3. Initiation patterns of flower and floral organ development in Arabidopsis thaliana.

    Science.gov (United States)

    Bossinger, G; Smyth, D R

    1996-04-01

    Sector boundary analysis has been used to deduce the number and orientation of cells initiating flower and floral organ development in Arabidopsis thaliana. Sectors were produced in transgenic plants carrying the Ac transposon from maize inserted between the constitutive 35S promoter and the GUS reporter gene. Excision of the transposon results in a blue-staining sector. Plants were chosen in which an early arising sector passed from vegetative regions into the inflorescence and through a mature flower. The range of sector boundary positions seen in mature flowers indicated that flower primordia usually arise from a group of four cells on the inflorescence flank. The radial axes of the mature flower are apparently set by these cells, supporting the concept that they act as a structural template. Floral organs show two patterns of initiation, a leaf-like pattern with eight cells in a row (sepals and carpels), or a shoot-like pattern with four cells in a block (stamens). The petal initiation pattern involved too few cells to allow assignment. The numbers of initiating cells were close to those seen when organ growth commenced in each case, indicating that earlier specification of floral organ development does not occur. By examining sector boundaries in homeotic mutant flowers in which second whorl organs develop as sepal-like organs rather than petals, we have shown that their pattern of origin is position dependent rather than identity dependent. PMID:8620836

  4. Overexpression of fatty acid amide hydrolase induces early flowering in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Neal D. Teaster

    2012-02-01

    Full Text Available N-Acylethanolamines (NAEs are bioactive lipids derived from the hydrolysis of the membrane phospholipid N-acylphosphatidylethanolamine (NAPE. In animal systems this reaction is part of the endocannabinoid signaling pathway, which regulates a variety of physiological processes. The signaling function of NAE is terminated by fatty acid amide hydrolase (FAAH, which hydrolyzes NAE to ethanolamine and free fatty acid. Our previous work in Arabidopsis thaliana showed that overexpression of AtFAAH (At5g64440 lowered endogenous levels of NAEs in seeds, consistent with its role in NAE signal termination. Reduced NAE levels were accompanied by an accelerated growth phenotype, increased sensitivity to abscisic acid (ABA, enhanced susceptibility to bacterial pathogens, and early flowering. Here we investigated the nature of the early flowering phenotype of AtFAAH overexpression. AtFAAH overexpressors flowered several days earlier than wild type and AtFAAH knockouts under both non-inductive short day (SD and inductive long day (LD conditions. Microarray analysis revealed that the FLOWERING LOCUS T (FT gene, which plays a major role in regulating flowering time, and one target MADS box transcription factor, SEPATALLA3 (SEP3, were elevated in AtFAAH overexpressors. Furthermore, AtFAAH overexpressors, with the early flowering phenotype had lower endogenous NAE levels in leaves compared to wild type prior to flowering. Exogenous application of NAE 12:0, which was reduced by up to 30% in AtFAAH overexpressors, delayed the onset of flowering in wild type plants. We conclude that the early flowering phenotype of AtFAAH overexpressors is, in part, explained by elevated FT gene expression resulting from the enhanced NAE hydrolase activity of AtFAAH, suggesting that NAE metabolism may participate in floral signaling pathways.

  5. Transcription profiling by array of Arabidopsis thaliana wild type (Col-0) and flowering time mutants to investigate synchronized induction of flowering

    OpenAIRE

    Valentim, F.L.; Mourik, van, J.A.; Posé, D.; Kim, M.C.; M. Schmid; van der Ham; Busscher, M.; Sanchez-Perez, G.F.; Molenaar, J.; Immink, G.H.; Dijk, van, G.

    2013-01-01

    Synchronized induction of flowering in Arabidopsis thaliana wild type (Col-0) and flowering time mutants (soc1, agl24, fd) by shifting from short day (8 hr light, 16 hr dark; 23C; 65% rel humidity) to long day (16 hr light, 8 hr dark; 23C; 65% rel humidity) for 0, 3, 5, and 7 days. Biotinylated probes were synthesized from RNA isolated from manually disseted shoot meristems and hybridized to Affymetrix ATH1 arrays.

  6. A novel high efficiency, low maintenance, hydroponic system for synchronous growth and flowering of Arabidopsis thaliana

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    Bernier Georges

    2003-01-01

    Full Text Available Abstract 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.

  7. Dynamics of Jasmonate Metabolism upon Flowering and across Leaf Stress Responses in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Emilie Widemann

    2016-01-01

    Full Text Available The jasmonic acid (JA signaling pathway plays important roles in adaptation of plants to environmental cues and in specific steps of their development, particularly in reproduction. Recent advances in metabolic studies have highlighted intricate mechanisms that govern enzymatic conversions within the jasmonate family. Here we analyzed jasmonate profile changes upon Arabidopsis thaliana flower development and investigated the contribution of catabolic pathways that were known to turnover the active hormonal compound jasmonoyl-isoleucine (JA-Ile upon leaf stress. We report a rapid decline of JA-Ile upon flower opening, concomitant with the massive accumulation of its most oxidized catabolite, 12COOH-JA-Ile. Detailed genetic analysis identified CYP94C1 as the major player in this process. CYP94C1 is one out of three characterized cytochrome P450 enzymes that define an oxidative JA-Ile turnover pathway, besides a second, hydrolytic pathway represented by the amido-hydrolases IAR3 and ILL6. Expression studies combined with reporter gene analysis revealed the dominant expression of CYP94C1 in mature anthers, consistent with the established role of JA signaling in male fertility. Significant CYP94B1 expression was also evidenced in stamen filaments, but surprisingly, CYP94B1 deficiency was not associated with significant changes in JA profiles. Finally, we compared global flower JA profiles with those previously reported in leaves reacting to mechanical wounding or submitted to infection by the necrotrophic fungus Botrytis cinerea. These comparisons revealed distinct dynamics of JA accumulation and conversions in these three biological systems. Leaf injury boosts a strong and transient JA and JA-Ile accumulation that evolves rapidly into a profile dominated by ω-oxidized and/or Ile-conjugated derivatives. In contrast, B. cinerea-infected leaves contain mostly unconjugated jasmonates, about half of this content being ω-oxidized. Finally, developing

  8. Dynamics of Jasmonate Metabolism upon Flowering and across Leaf Stress Responses in Arabidopsis thaliana.

    Science.gov (United States)

    Widemann, Emilie; Smirnova, Ekaterina; Aubert, Yann; Miesch, Laurence; Heitz, Thierry

    2016-01-01

    The jasmonic acid (JA) signaling pathway plays important roles in adaptation of plants to environmental cues and in specific steps of their development, particularly in reproduction. Recent advances in metabolic studies have highlighted intricate mechanisms that govern enzymatic conversions within the jasmonate family. Here we analyzed jasmonate profile changes upon Arabidopsis thaliana flower development and investigated the contribution of catabolic pathways that were known to turnover the active hormonal compound jasmonoyl-isoleucine (JA-Ile) upon leaf stress. We report a rapid decline of JA-Ile upon flower opening, concomitant with the massive accumulation of its most oxidized catabolite, 12COOH-JA-Ile. Detailed genetic analysis identified CYP94C1 as the major player in this process. CYP94C1 is one out of three characterized cytochrome P450 enzymes that define an oxidative JA-Ile turnover pathway, besides a second, hydrolytic pathway represented by the amido-hydrolases IAR3 and ILL6. Expression studies combined with reporter gene analysis revealed the dominant expression of CYP94C1 in mature anthers, consistent with the established role of JA signaling in male fertility. Significant CYP94B1 expression was also evidenced in stamen filaments, but surprisingly, CYP94B1 deficiency was not associated with significant changes in JA profiles. Finally, we compared global flower JA profiles with those previously reported in leaves reacting to mechanical wounding or submitted to infection by the necrotrophic fungus Botrytis cinerea. These comparisons revealed distinct dynamics of JA accumulation and conversions in these three biological systems. Leaf injury boosts a strong and transient JA and JA-Ile accumulation that evolves rapidly into a profile dominated by ω-oxidized and/or Ile-conjugated derivatives. In contrast, B. cinerea-infected leaves contain mostly unconjugated jasmonates, about half of this content being ω-oxidized. Finally, developing flowers present an

  9. Involvement of the Putative N-Acetylornithine Deacetylase from Arabidopsis thaliana in Flowering and Fruit Development.

    Science.gov (United States)

    Molesini, Barbara; Mennella, Giuseppe; Martini, Flavio; Francese, Gianluca; Pandolfini, Tiziana

    2015-06-01

    In eukaryotic cells, the non-proteinogenic amino acid ornithine is the precursor of arginine and polyamines (PAs). The final step of ornithine biosynthesis occurs in plants via a cyclic pathway catalyzed by N(2)-acetylornithine:N-acetylglutamate acetyltransferase (NAOGAcT). An alternative route for ornithine formation, the linear pathway, has been reported for enteric bacteria and a few other organisms; the acetyl group of N(2)-acetylornithine is released as acetate by N(2)-acetylornithine deacetylase (NAOD). NAOD activity has never been demonstrated in plants, although many putative NAOD-like genes have been identified. In this investigation, we examined the effect of down-regulation of the putative Arabidopsis thaliana NAOD gene by using AtNAOD-silenced (sil#17) and T-DNA insertional mutant (atnaod) plants. The ornithine content was consistently reduced in sil#17 and atnaod plants compared with wild-type plants, suggesting that in addition to NAOGAcT action, AtNAOD contributes to the regulation of ornithine levels in plant cells. Ornithine depletion was associated with altered levels of putrescine and spermine. Reduced AtNAOD expression resulted in alterations at the reproductive level, causing early flowering and impaired fruit setting. In this regard, the highest level of AtNAOD expression was observed in unfertilized ovules. Our findings suggest that AtNAOD acts as a positive regulator of fruit setting and agree with those obtained in tomato auxin-synthesizing parthenocarpic plants, where induction of SlNAOD was associated with the onset of ovary growth. Thus, here we have uncovered the first hints of the functions of AtNAOD by connecting its role in flower and fruit development with the regulation of ornithine and PA levels. PMID:25713174

  10. A previously undescribed jasmonate compound in flowering Arabidopsis thaliana - The identification of cis-(+)-OPDA-Ile

    Czech Academy of Sciences Publication Activity Database

    Floková, K.; Feussner, K.; Herrfurth, C.; Miersch, O.; Mik, V.; Tarkowská, Danuše; Strnad, Miroslav; Feussner, I.; Wasternack, Claus; Novák, Ondřej

    2016-01-01

    Roč. 122, FEB (2016), s. 230-237. ISSN 0031-9422 R&D Projects: GA MŠk(CZ) LO1204; GA MŠk LK21306 Institutional support: RVO:61389030 Keywords : Arabidopsis thaliana (Brassicaceae) * Jasmonates * Cis-(+)-12-oxo-phytodienoyl-L-isoleucine Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.547, year: 2014

  11. Direct and indirect selection on flowering time, water-use efficiency (WUE, δ 13C), and WUE plasticity to drought in Arabidopsis thaliana

    OpenAIRE

    Kenney, Amanda M; McKay, John K.; Richards, James H.; Thomas E Juenger

    2014-01-01

    Flowering time and water-use efficiency (WUE) are two ecological traits that are important for plant drought response. To understand the evolutionary significance of natural genetic variation in flowering time, WUE, and WUE plasticity to drought in Arabidopsis thaliana, we addressed the following questions: (1) How are ecophysiological traits genetically correlated within and between different soil moisture environments? (2) Does terminal drought select for early flowering and drought escape?...

  12. Integrating roots into a whole plant network of flowering time genes in Arabidopsis thaliana.

    Science.gov (United States)

    Bouché, Frédéric; D'Aloia, Maria; Tocquin, Pierre; Lobet, Guillaume; Detry, Nathalie; Périlleux, Claire

    2016-01-01

    Molecular data concerning the involvement of roots in the genetic pathways regulating floral transition are lacking. In this study, we performed global analyses of the root transcriptome in Arabidopsis in order to identify flowering time genes that are expressed in the roots and genes that are differentially expressed in the roots during the induction of flowering. Data mining of public microarray experiments uncovered that about 200 genes whose mutations are reported to alter flowering time are expressed in the roots (i.e. were detected in more than 50% of the microarrays). However, only a few flowering integrator genes passed the analysis cutoff. Comparison of root transcriptome in short days and during synchronized induction of flowering by a single 22-h long day revealed that 595 genes were differentially expressed. Enrichment analyses of differentially expressed genes in root tissues, gene ontology categories, and cis-regulatory elements converged towards sugar signaling. We concluded that roots are integrated in systemic signaling, whereby carbon supply coordinates growth at the whole plant level during the induction of flowering. This coordination could involve the root circadian clock and cytokinin biosynthesis as a feed forward loop towards the shoot. PMID:27352932

  13. Leaf Downward Curvature and Delayed Flowering Caused by AtLH Overexpression in Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    WUHao; YULin; TANGXiang-Rong; SHENRui-Juan; HEYu-Ke

    2004-01-01

    AtLHgene of Arabidopsis is a BcpLH(leafy head) homolog of Chinese cabbage, which encodes a double-stranded RNA-binding protein related to the curvature of folding leaf leading to the formation of leafy head. In order to elucidate the regulatory function of AtLH in the development of leaf curvature, we made a construct of 35S::AtLHand transformed it to Arabidopsis. In transgenic plants for sense-AtLH, transcripts of AtLH gene were increased significantly in leaves and flowers, giving rise to the AtLH-overexpressed plants in which the rosette leaves curved downward or outward in a manner of enhanced epinastic growth. Compared with normal plants, bolting and flowering time of the transgenic plants was significantly delayed. Moreover, the apical dominance of transgenic plants was weaker in vegetative shoots since more axillary shoots emerged from axil of rosette leaves, while stronger in flowering shoots because fewer cauline inflorescences were observed on the main inflorescence. In other aspects, these transgenic plants exhibited an increase in root-stimulating response to IAA and decrease in root-inhibitory reaction on ABA. It indicates that overexpression of AtLH causes downward curvature of transgenic plants.

  14. Spatial distribution of the RABBIT EARS protein and effects of its ectopic expression in Arabidopsis thaliana flowers.

    Science.gov (United States)

    Takeda, Seiji; Noguchi, Mariko; Hamamura, Yuki; Higashiyama, Tetsuya

    2014-03-01

    In many flowering plants, flowers consist of two peripheral organs, sepals and petals, occurring in outer two whorls, and two inner reproductive organs, stamens and carpels. These organs are arranged in a concentric pattern in a floral meristem, and the organ identity is established by the combined action of floral homeotic genes expressed along the whorls. Floral organ primordia arise at fixed positions in the floral meristem within each whorl. The RABBIT EARS (RBE) gene is transcribed in the petal precursor cells and primordia, and regulates petal initiation and early growth in Arabidopsis thaliana. We investigated the spatial and temporal expression pattern of a RBE protein fused to the green fluorescent protein (GFP). Expression of the GFP:RBE fusion gene under the RBE cis-regulatory genomic fragment rescues the rbe petal defects, indicating that the fusion protein is functional. The GFP signal is located to the cells where RBE is transcribed, suggesting that RBE function is cell-autonomous. Ectopic expression of GFP:RBE under the APETALA1 promoter causes the homeotic conversion of floral organs, resulting in sterile flowers. In these plants, the class B homeotic genes APETALA3 and PISTILLATA are down-regulated, suggesting that the restriction of the RBE expression to the petal precursor cells is crucial for flower development. PMID:24366683

  15. Genetic analyses of interactions among gibberellin, abscisic acid, and brassinosteroids in the control of flowering time in Arabidopsis thaliana.

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    Malgorzata A Domagalska

    Full Text Available BACKGROUND: Genetic interactions between phytohormones in the control of flowering time in Arabidopsis thaliana have not been extensively studied. Three phytohormones have been individually connected to the floral-timing program. The inductive function of gibberellins (GAs is the most documented. Abscisic acid (ABA has been demonstrated to delay flowering. Finally, the promotive role of brassinosteroids (BRs has been established. It has been reported that for many physiological processes, hormone pathways interact to ensure an appropriate biological response. METHODOLOGY: We tested possible genetic interactions between GA-, ABA-, and BR-dependent pathways in the control of the transition to flowering. For this, single and double mutants deficient in the biosynthesis of GAs, ABA, and BRs were used to assess the effect of hormone deficiency on the timing of floral transition. Also, plants that over-express genes encoding rate-limiting enzymes in each biosynthetic pathway were generated and the flowering time of these lines was investigated. CONCLUSIONS: Loss-of-function studies revealed a complex relationship between GAs and ABA, and between ABA and BRs, and suggested a cross-regulatory relation between GAs to BRs. Gain-of-function studies revealed that GAs were clearly limiting in their sufficiency of action, whereas increases in BRs and ABA led to a more modest phenotypic effect on floral timing. We conclude from our genetic tests that the effects of GA, ABA, and BR on timing of floral induction are only in partially coordinated action.

  16. Effect of Mitochondrial Dysfunction on Carbon Metabolism and Gene Expression in Flower Tissues of Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    Maria V.Busi; Maria E.Gomez-Lobato; Sebastian P.Rius; Valeria R.Turowski; Paula Casati; Eduardo J.Zabaleta; Diego F.Gomez-Casati; Alejandro Araya

    2011-01-01

    We characterized the transcriptomic response of transgenic plants carrying a mitochondrial dysfunction induced by the expression of the unedited form of the ATP synthase subunit 9.The u-ATP9 transgene driven by A9 and APETALA3 promoters induce mitochondrial dysfunction revealed by a decrease jn both oxygen uptake and adenine nucleotides(ATP,ADP)levels without changes in the ATP/ADP ratio.Furthermore,we measured an increase in ROS accumulation and a decrease in glutathione and ascorbate levels with a concomitant oxidative stress response.The transcriptome analysis of young Arabidopsis flowers,validated by Qrt-PCR and enzymatic or functional tests,showed dramatic changes in u-ATP9 plants.Both lines display a modification in the expression of various genes involved in carbon,lipid,and cell wall metabolism,suggesting that an important metabolic readjustment occurs in plants with a mitochondrial dysfunction.Interestingly,transcript levels involved in mitochondrial respiration,protein synthesis,and degradation are affected.Moreover,the Ievels of several mRNAs encoding for transcription factors and DNA binding proteins were also changed.Some of them are involved in stress and hormone responses,suggesting that several signaling pathways overlap.Indeed,the transcriptome data revealed that the mitochondrial dysfunction dramatically alters the expression of genes involved in signaling pathways,including those related to ethylene,absicic acid,and auxin signal transduction.Our data suggest that the mitochondrial dysfunction model used in this report may be usefuI to uncover the retrograde signaling mechanism between the nucleus and mitochondria in plant cells.

  17. Dissection of the Role of FT and FD in the Regulation of Flowering in Arabidopsis thaliana

    OpenAIRE

    Srikanth, Anusha

    2012-01-01

    The transition to flowering is under the control of various endogenous and environmental factors. These factors are perceived in different parts of the plant and trigger signaling cascades that are integrated at the shoot apex to eventually initiate the formation of flowers. Photoperiod is an important environmental regulator that controls flowering time. Daylength, which is perceived in the leaves, triggers a relay of signals that eventually lead to flowering. Genes like GIGANTEA and CONSTAN...

  18. Comparison of Flowering Time Genes in Brassica Rapa, B. Napus and Arabidopsis Thaliana

    OpenAIRE

    Osborn, T C; Kole, C; Parkin, IAP.; Sharpe, A. G.; Kuiper, M.; Lydiate, D J; Trick, M.

    1997-01-01

    The major difference between annual and biennial cultivars of oilseed Brassica napus and B. rapa is conferred by genes controlling vernalization-responsive flowering time. These genes were compared between the species by aligning the map positions of flowering time quantitative trait loci (QTLs) detected in a segregating population of each species. The results suggest that two major QTLs identified in B. rapa correspond to two major QTLs identified in B. napus. Since B. rapa is one of the hyp...

  19. Capsella rubella TGA4, a bZIP transcription factor, causes delayed flowering in Arabidopsis thaliana

    OpenAIRE

    Li Maofu; Wang Hua; Yang Yuan; Jin Wanmei

    2016-01-01

    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 ...

  20. A novel high efficiency, low maintenance, hydroponic system for synchronous growth and flowering of Arabidopsis thaliana

    OpenAIRE

    Bernier Georges; Kurtem Emile; Pieltain Alexandra; Havelange Andrée; Corbesier Laurent; Tocquin Pierre; Périlleux Claire

    2003-01-01

    Abstract 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 roset...

  1. Upland cotton gene GhFPF1 confers promotion of flowering time and shade-avoidance responses in Arabidopsis thaliana.

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    Xiaoyan Wang

    Full Text Available Extensive studies on floral transition in model species have revealed a network of regulatory interactions between proteins that transduce and integrate developmental and environmental signals to promote or inhibit the transition to flowering. Previous studies indicated FLOWERING PROMOTING FACTOR 1 (FPF1 gene was involved in the promotion of flowering, but the molecular mechanism was still unclear. Here, FPF1 homologous sequences were screened from diploid Gossypium raimondii L. (D-genome, n = 13 and Gossypium arboreum L. genome (A-genome, n = 13 databases. Orthologous genes from the two species were compared, suggesting that distinctions at nucleic acid and amino acid levels were not equivalent because of codon degeneracy. Six FPF1 homologous genes were identified from the cultivated allotetraploid Gossypium hirsutum L. (AD-genome, n = 26. Analysis of relative transcripts of the six genes in different tissues revealed that this gene family displayed strong tissue-specific expression. GhFPF1, encoding a 12.0-kDa protein (Accession No: KC832319 exerted more transcripts in floral apices of short-season cotton, hinting that it could be involved in floral regulation. Significantly activated APETALA 1 and suppressed FLOWERING LOCUS C expression were induced by over-expression of GhFPF1 in the Arabidopsis Columbia-0 ecotype. In addition, transgenic Arabidopsis displayed a constitutive shade-avoiding phenotype that is characterized by long hypocotyls and petioles, reduced chlorophyll content, and early flowering. We propose that GhFPF1 may be involved in flowering time control and shade-avoidance responses.

  2. Over-expression of the PaAP1 gene from sweet cherry (Prunus avium L.) causes early flowering in Arabidopsis thaliana.

    Science.gov (United States)

    Wang, Jing; Zhang, Xiaoming; Yan, Guohua; Zhou, Yu; Zhang, Kaichun

    2013-02-15

    A homologue of SQUAMOSA/APETALA1, designated PaAP1, was isolated from Prunus avium by reverse transcription-PCR (RT-PCR). The full length of PaAP1 cDNA is 753 bp, and it codes for a polypeptide of 250 amino acid residues. Sequence comparison revealed that PaAP1 belongs to the MADS-box gene family. Phylogenetic analysis indicated that PaAP1 shared the highest identity with SQUA/AP1 homologues from Prunus serrulata. Real-time fluorescence quantitative PCR analysis showed that PaAP1 was expressed at high levels in petal, sepal, style, and flower buds, which was slightly different from the expression pattern of AP1 of Arabidopsis thaliana. To characterize the functions of PaAP1, we assessed Arabidopsis transformed with 35S::PaAP1. A total of 8 transgenic T(1) lines with an early flowering phenotype were obtained, and a 3:1 segregation ratio of flowering time was observed in the T(2) generation of 4 lines. This study provides the first functional analysis of an SQUA/AP1 homolog from P. avium and suggests that PaAP1 is potentially useful for shortening the juvenile period in sweet cherry. PMID:23206932

  3. AINTEGUMENTA-LIKE genes have partly overlapping functions with AINTEGUMENTA but make distinct contributions to Arabidopsis thaliana flower development.

    Science.gov (United States)

    Krizek, Beth A

    2015-08-01

    AINTEGUMENTA (ANT) is an important regulator of Arabidopsis flower development that has overlapping functions with the related AINTEGUMENTA-LIKE6 (AIL6) gene in floral organ initiation, identity specification, growth, and patterning. Two other AINTEGUMENTA-LIKE (AIL) genes, AIL5 and AIL7, are expressed in developing flowers in spatial domains that partly overlap with those of ANT. Here, it is shown that AIL5 and AIL7 also act in a partially redundant manner with ANT. The results demonstrate that AIL genes exhibit unequal genetic redundancy with roles for AIL5, AIL6, and AIL7 only revealed in the absence of ANT function. ant ail5 and ant ail7 double mutant flowers show alterations in floral organ positioning and growth, sepal fusion, and reductions in petal number. In ant ail5, petals are often replaced by filaments or dramatically reduced in size. ant ail7 double mutants produce increased numbers of carpels, which have defects in valve fusion and a loss of apical tissues. The distinct phenotypes of ant ail5, ant ail7 and the previously characterized ant ail6 indicate that AIL5, AIL6, and AIL7 make unique contributions to flower development. These distinct roles are also supported by genetic analyses of ant ail triple mutants. While ant ail5 ail6 triple mutants closely resemble ant ail6 double mutants, ant ail5 ail7 triple mutants exhibit more severe deviations from the wild type than either ant ail5 or ant ail7 double mutants. Furthermore, it is shown that AIL5, AIL6, and AIL7 act in a dose dependent manners in ant and other mutant backgrounds. PMID:25956884

  4. Selenium Speciation in Arabidopsis Thaliana

    OpenAIRE

    Wang, Xiaoou

    2011-01-01

    Selenium has been proved as an essential micronutrient and is beneficial to animals and humans. It is a structural component of the important antioxidant enzyme, glutathione peroxidase, which catalyzes reactions to detoxify reactive oxygen species. However, the essentiality of Se in plants remains controversial and the protective role of Se in plants has rarely been investigated. In this study, Arabidopsis thaliana was grown in controlled environments having selenate or selenite enriched medi...

  5. Omics analysis of high-energy Arabidopsis thaliana

    OpenAIRE

    Liang, Chao; 梁超

    2014-01-01

    Arabidopsis thaliana purple acid phosphatase 2 (AtPAP2) is a phosphatase dually targeted to both chloroplasts and mitochondria. Overexpression (OE) of AtPAP2 in Arabidopsis thaliana was reported to speed up plant growth and promote flowering, seed yield and biomass at maturity in a previous study. Under long-day (16 hours light at 22°C / 8 hours dark at 18°C) growth conditions, the leaves of 20-day-old OE lines contained significant higher sucrose and glucose than the wild-type (WT) plants, r...

  6. Quantitative trait loci for floral morphology in Arabidopsis thaliana.

    OpenAIRE

    Juenger, T; Purugganan, M.; Mackay, T F

    2000-01-01

    A central question in biology is how genes control the expression of quantitative variation. We used statistical methods to estimate genetic variation in eight Arabidopsis thaliana floral characters (fresh flower mass, petal length, petal width, sepal length, sepal width, long stamen length, short stamen length, and pistil length) in a cosmopolitan sample of 15 ecotypes. In addition, we used genome-wide quantitative trait locus (QTL) mapping to evaluate the genetic basis of variation in these...

  7. Bioavailability of nanoparticulate hematite to Arabidopsis thaliana

    International Nuclear Information System (INIS)

    The environmental effects and bioavailability of nanoparticulate iron (Fe) to plants are currently unknown. Here, plant bioavailability of synthesized hematite Fe nanoparticles was evaluated using Arabidopsis thaliana (A. thaliana) as a model. Over 56-days of growing wild-type A. thaliana, the nanoparticle-Fe and no-Fe treatments had lower plant biomass, lower chlorophyll concentrations, and lower internal Fe concentrations than the Fe-treatment. Results for the no-Fe and nanoparticle-Fe treatments were consistently similar throughout the experiment. These results suggest that nanoparticles (mean diameter 40.9 nm, range 22.3–67.0 nm) were not taken up and therefore not bioavailable to A. thaliana. Over 14-days growing wild-type and transgenic (Type I/II proton pump overexpression) A. thaliana, the Type I plant grew more than the wild-type in the nanoparticle-Fe treatment, suggesting Type I plants cope better with Fe limitation; however, the nanoparticle-Fe and no-Fe treatments had similar growth for all plant types. -- Highlights: ► Iron nanoparticles were synthesized and assessed for bioavailability to Arabidopsis. ► Arabidopsis grew better in the presence of EDTA-bound iron than nanoparticulate iron. ► Arabidopsis grew the same in the presence of nanoparticulate iron compared to no iron. -- Synthesized iron nanoparticles were not bioavailable to Arabidopsis thaliana in agar nutrient media

  8. A Superfamily of Arabidopsis Thaliana Retrotransposons

    OpenAIRE

    Konieczny, A; Voytas, D. F.; Cummings, M. P.; Ausubel, F M

    1991-01-01

    We describe a superfamily of Arabidopsis thaliana retrotransposable elements that consists of at least ten related families designated Ta1-Ta10. The Ta1 family has been described previously. Two genomic clones representing the Ta2 and Ta3 elements were isolated from an A. thaliana (race Landsberg erecta) λ library using sequences derived from the reverse transcriptase region of Ta1 as hybridization probes. Nucleotide sequence analysis showed that the Ta1, Ta2 and Ta3 families share >75% amino...

  9. Exploring potential new floral organ morphogenesis genes of Arabidopsis thaliana using systems biology approach

    OpenAIRE

    Xie, Wenchuan; Huang, Junfeng; Liu, Yang; Rao, Jianan; Luo, Da; He, Miao

    2015-01-01

    Flowering is one of the important defining features of angiosperms. The initiation of flower development and the formation of different floral organs are the results of the interplays among numerous genes. But until now, just fewer genes have been found linked with flower development. And the functions of lots of genes of Arabidopsis thaliana are still unknown. Although, the quartet model successfully simplified the ABCDE model to elaborate the molecular mechanism by introducing protein-prote...

  10. Terpene Specialized Metabolism in Arabidopsis thaliana

    OpenAIRE

    Tholl, Dorothea; Lee, Sungbeom

    2011-01-01

    Terpenes constitute the largest class of plant secondary (or specialized) metabolites, which are compounds of ecological function in plant defense or the attraction of beneficial organisms. Using biochemical and genetic approaches, nearly all Arabidopsis thaliana (Arabidopsis) enzymes of the core biosynthetic pathways producing the 5-carbon building blocks of terpenes have been characterized and closer insight has been gained into the transcriptional and posttranscriptional/translational mech...

  11. Shotgun Proteomic Analysis of Arabidopsis thaliana Leaves

    Science.gov (United States)

    Two shotgun tandem mass spectrometry proteomics approaches, Multidimensional Protein Identification Technology (MudPIT) and 1D-Gel-LC-MS/MS, were used to identify Arabidopsis thaliana leaf proteins. These methods utilize different protein/peptide separation strategies. Detergents not compatible wit...

  12. Flavonoid-specific staining of Arabidopsis thaliana.

    Science.gov (United States)

    Sheahan, J J; Rechnitz, G A

    1992-12-01

    Crop yields may be threatened by increases in UV-B radiation resulting from depletion of the ozone layer. In higher plants, the presence of flavonols provides a protective mechanism, and we report a novel staining procedure for the visualization of such protectants in plant tissue. It is shown that the proposed technique provides sensitive and specific fluorescence of flavonoids in chlorophyll-bleached tissue of Arabidopsis thaliana. PMID:1282347

  13. Bioavailability of nanoparticulate hematite to Arabidopsis thaliana.

    Science.gov (United States)

    Marusenko, Yevgeniy; Shipp, Jessie; Hamilton, George A; Morgan, Jennifer L L; Keebaugh, Michael; Hill, Hansina; Dutta, Arnab; Zhuo, Xiaoding; Upadhyay, Nabin; Hutchings, James; Herckes, Pierre; Anbar, Ariel D; Shock, Everett; Hartnett, Hilairy E

    2013-03-01

    The environmental effects and bioavailability of nanoparticulate iron (Fe) to plants are currently unknown. Here, plant bioavailability of synthesized hematite Fe nanoparticles was evaluated using Arabidopsis thaliana (A. thaliana) as a model. Over 56-days of growing wild-type A. thaliana, the nanoparticle-Fe and no-Fe treatments had lower plant biomass, lower chlorophyll concentrations, and lower internal Fe concentrations than the Fe-treatment. Results for the no-Fe and nanoparticle-Fe treatments were consistently similar throughout the experiment. These results suggest that nanoparticles (mean diameter 40.9 nm, range 22.3-67.0 nm) were not taken up and therefore not bioavailable to A. thaliana. Over 14-days growing wild-type and transgenic (Type I/II proton pump overexpression) A. thaliana, the Type I plant grew more than the wild-type in the nanoparticle-Fe treatment, suggesting Type I plants cope better with Fe limitation; however, the nanoparticle-Fe and no-Fe treatments had similar growth for all plant types. PMID:23262070

  14. The alleles at the E1 locus impact the expression pattern of two soybean FT-like genes shown to induce flowering in Arabidopsis

    Science.gov (United States)

    A small gene family of phosphatidyl ethanolamine-binding proteins (PEBP) has been shown to function as key regulators in flowering; inArabidopsis thaliana the FT protein promotes flowering whilst theclosely related TFL1 protein represses flowering. Control of flowering time in soybean [Glycine max ...

  15. Arabidopsis thaliana glucuronosyltransferase in family GT14.

    Science.gov (United States)

    Dilokpimol, Adiphol; Geshi, Naomi

    2014-01-01

    Arabinogalactan proteins are abundant cell-surface proteoglycans in plants and are involved in many cellular processes including somatic embryogenesis, cell-cell interactions, and cell elongation. We reported a glucuronosyltransferase encoded by Arabidopsis AtGlcAT14A, which catalyzes an addition 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 AtGlcAT14A 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 AtGLCAT14A, 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 AtGlcAT14A. 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 AtGlcAT14B and AtGlcAT14C, respectively. PMID:24739253

  16. Heterologous expression of the Arabidopsis etr1-1 allele inhibits the senescence of carnation flowers

    NARCIS (Netherlands)

    Bovy, A.G.; Angenent, G.C.; Dons, H.J.M.; Altvorst, van A.

    1999-01-01

    The Arabidopsis thaliana etr1-1 allele, capable of conferring ethylene insensitivity in a heterologous host, was introduced into transgenic carnation plants. This gene was expressed under control of either its own promoter, the constitutive CaMV 35S promoter or the flower-specific petunia FBP1 promo

  17. 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.

  18. Arabidopsis flower development-of protein complexes, targets, and transport.

    Science.gov (United States)

    Becker, Annette; Ehlers, Katrin

    2016-03-01

    Tremendous progress has been achieved over the past 25 years or more of research on the molecular mechanisms of floral organ identity, patterning, and development. While collections of floral homeotic mutants of Antirrhinum majus laid the foundation already at the beginning of the previous century, it was the genetic analysis of these mutants in A. majus and Arabidopsis thaliana that led to the development of the ABC model of floral organ identity more than 20 years ago. This intuitive model kick-started research focused on the genetic mechanisms regulating flower development, using mainly A. thaliana as a model plant. In recent years, interactions among floral homeotic proteins have been elucidated, and their direct and indirect target genes are known to a large extent. Here, we provide an overview over the advances in understanding the molecular mechanism orchestrating A. thaliana flower development. We focus on floral homeotic protein complexes, their target genes, evidence for their transport in floral primordia, and how these new results advance our view on the processes downstream of floral organ identity, such as organ boundary formation or floral organ patterning. PMID:25845756

  19. Flower Development

    OpenAIRE

    Alvarez-Buylla, Elena R; Benítez, Mariana; Corvera-Poiré, Adriana; Chaos Cador, Álvaro; De Folter, Stefan; Gamboa de Buen, Alicia; Garay-Arroyo, Adriana; García-Ponce, Berenice; Jaimes-Miranda, Fabiola; Pérez-Ruiz, Rigoberto V.; Piñeyro-Nelson, Alma; Sánchez-Corrales, Yara E.

    2010-01-01

    Flowers are the most complex structures of plants. Studies of Arabidopsis thaliana, which has typical eudicot flowers, have been fundamental in advancing the structural and molecular understanding of flower development. The main processes and stages of Arabidopsis flower development are summarized to provide a framework in which to interpret the detailed molecular genetic studies of genes assigned functions during flower development and is extended to recent genomics studies uncovering the ke...

  20. 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

  1. Arabidopsis thaliana Inspired Genetic Restoration Strategies

    Directory of Open Access Journals (Sweden)

    Donagh Hatton

    2013-04-01

    Full Text Available A controversial genetic restoration mechanism has been proposed for the model organism Arabidopsis thaliana. This theory proposes that genetic material from non-parental ancestors is used to restore genetic information that was inadvertently corrupted during reproduction. We evaluate the effectiveness of this strategy by adapting it to an evolutionary algorithm solving two distinct benchmark optimization problems. We compare the performance of the proposed strategy with a number of alternate strategies – including the Mendelian alternative. Included in this comparison are a number of biologically implausible templates that help elucidate likely reasons for the relative performance of the different templates. Results show that the proposed non- Mendelian restoration strategy is highly effective across the range of conditions investigated – significantly outperforming the Mendelian alternative in almost every situation.

  2. Ectopic Expression of BraYAB1-702, a Member of YABBY Gene Family in Chinese Cabbage, Causes Leaf Curling, Inhibition of Development of Shoot Apical Meristem and Flowering Stage Delaying in Arabidopsis thaliana

    OpenAIRE

    Lu-Gang Zhang; Jing Zhang; Ze-Ping Yang; Xin-Ling Zhang

    2013-01-01

    YABBY gene family plays an important role in the polarity development of lateral organs. We isolated the BraYAB1-702 gene, a member of the YABBY gene family, from young leaves of Chinese cabbage line 06J45. The full-length gene has a 937 bp CDNA sequence and contains an open reading frame (ORF) of 702 bp. The subcellular localization analysis showed that the expression product of the gene was localized in the nucleus. Ectopic expression of BraYAB1-702 in Arabidopsis thaliana caused leaf curli...

  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. Momilactone sensitive proteins in Arabidopsis thaliana.

    Science.gov (United States)

    Kato-Noguchi, Hisashi; Kitajima, Shinya

    2015-05-01

    The labdane-related diterpenoid, momilactone B has potent growth inhibitory activity and was demonstrated to play a particularly critical role in the allelopathy of rice (Oryza sativa L.). However, there is limited information available about the mode of action of momilactone B on the growth inhibition. The present research describes the effects of momilactone B on protein expression in the early development of Arabidopsis thaliana seedling, which was determined by two-dimensional electrophoresis and MALDI-TOFMS. Momilactone B inhibited the accumulation of subtilisin-like serine protease, amyrin synthase LUP2, β-glucosidase and malate synthase at 1 h after the momilactone application. Those proteins are involved in the metabolic turnover and the production of intermediates needed for cell structures resulting in plant growth and development. Momilactone B also inhibited the breakdown of cruciferin 2, which is essential for seed germination and seedling growth to construct cell structures. Momilactone B induced the accumulation of translationally controlled tumor protein, glutathione S-transferase and 1-cysteine peroxiredoxin 1. These proteins are involved in stress responses and increased stress tolerance. In addition, glutathione S-transferase has the activity of herbicide detoxification and 1-cysteine peroxiredoxin 1 has inhibitory activity for seed germination under unfavorable conditions. The present research suggests that momilactone B may inhibit the seedling growth by the inhibition of the metabolic turnover and the production of intermediates for cell structures. In addition, momilactone induced proteins associated with plant defense responses. PMID:26058145

  5. [Arabidopsis thaliana accessions - a tool for biochemical and phylogentical studies].

    Science.gov (United States)

    Szymańska, Renata; Gabruk, Michał; Kruk, Jerzy

    2015-01-01

    Arabidopsis thaliana since a few decades is used as a model for biological and plant genetic research. Natural variation of this species is related to its geographical range which covers different climate zones and habitats. The ability to occupy such a wide area by Arabidopsis is possible due to its stress tolerance and adaptability. Arabidopsis accessions exhibit phenotypic and genotypic variation, which is a result of adaptation to local environmental conditions. During development, plants are subjected to various stress factors. Plants show a spectrum of reactions, processes and phenomena that determine their survival in these adverse conditions. The response of plants to stress involves signal detection and transmission. These reactions are different and depend on the stressor, its intensity, plant species and life strategy. It is assumed that the populations of the same species from different geographical regions acclimated to the stress conditions develop a set of alleles, which allow them to grow and reproduce. Therefore, the study of natural variation in response to abiotic stress among Arabidopsis thaliana accessions allows to find key genes or alleles, and thus the mechanisms by which plants cope with adverse physical and chemical conditions. This paper presents an overview of recent findings, tools and research directions used in the study of natural variation in Arabidopsis thaliana accessions. Additionally, we explain why accessions can be used in the phylogenetic analyses and to study demography and migration of Arabidopsis thaliana. PMID:26281359

  6. Sequence and organization of 5S ribosomal RNA-encoding genes of Arabidopsis thaliana.

    Science.gov (United States)

    Campell, B R; Song, Y; Posch, T E; Cullis, C A; Town, C D

    1992-03-15

    We have isolated a genomic clone containing Arabidopsis thaliana 5S ribosomal RNA (rRNA)-encoding genes (rDNA) by screening an A. thaliana library with a 5S rDNA probe from flax. The clone isolated contains seven repeat units of 497 bp, plus 11 kb of flanking genomic sequence at one border. Sequencing of individual subcloned repeat units shows that the sequence of the 5S rRNA coding region is very similar to that reported for other flowering plants. Four A. thaliana ecotypes were found to contain approx. 1000 copies of 5S rDNA per haploid genome. Southern-blot analysis of genomic DNA indicates that 5S rDNA occurs in long tandem arrays, and shows the presence of numerous restriction-site polymorphisms among the six ecotypes studied. PMID:1348233

  7. 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.

  8. Quantitative proteomics approaches to study leaf senescence in Arabidopsis thaliana

    OpenAIRE

    Hebeler, Romano

    2007-01-01

    Im Vergleich zu Arabidopsis thaliana Wildtyppflanzen zeigen onset of leaf death (old) Mutanten vorgezogene Blattseneszenz. Ziel der Arbeit war es, mittels relativ quantitativer Proteomics molekulare Prozesse der frühen Blattseneszenz zu analysieren. Zwei-dimensionale "difference gel electrophoresis" (DIGE) wurde eingesetzt, um Unterschiede in den Proteinkonzentrationen von A. thaliana mit normaler und veränderter Blattseneszenz zu bestimmen. Die regulierten Proteine wurden durc...

  9. Transcriptomic analysis of Arabidopsis overexpressing flowering locus T driven by a meristem-specific promoter that induces early flowering.

    Science.gov (United States)

    Duplat-Bermúdez, L; Ruiz-Medrano, R; Landsman, D; Mariño-Ramírez, L; Xoconostle-Cázares, B

    2016-08-10

    Here we analyzed in leaves the effect of FT overexpression driven by meristem-specific KNAT1 gene homolog of Arabidopsis thaliana (Lincoln et al., 1994; Long et al., 1996) on the transcriptomic response during plant development. Our results demonstrated that meristematic FT overexpression generates a phenotype with an early flowering independent of photoperiod when compared with wild type (WT) plants. Arabidopsis FT-overexpressor lines (AtFTOE) did not show significant differences compared with WT lines neither in leaf number nor in rosette diameter up to day 21, when AtFTOE flowered. After this period AtFTOE plants started flower production and no new rosette leaves were produced. Additionally, WT plants continued on vegetative stage up to day 40, producing 12-14 rosette leaves before flowering. Transcriptomic analysis of rosette leaves studied by sequencing Illumina RNA-seq allowed us to determine the differential expression in mature leaf rosette of 3652 genes, being 626 of them up-regulated and 3026 down-regulated. Overexpressed genes related with flowering showed up-regulated transcription factors such as MADS-box that are known as flowering markers in meristem and which overexpression has been related with meristem identity preservation and the transition from vegetative to floral stage. Genes related with sugar transport have shown a higher demand of monosaccharides derived from the hydrolysis of sucrose to glucose and probably fructose, which can also be influenced by reproductive stage of AtFTOE plants. PMID:27154816

  10. Transcriptomic analysis of Arabidopsis overexpressing flowering locus T driven by a meristem-specific promoter that induces early flowering

    Science.gov (United States)

    Duplat-Bermúdez, L.; Ruiz-Medrano, R.; Landsman, D.; Mariño-Ramírez, L.; Xoconostle-Cázares, B.

    2016-01-01

    Here we analyzed in leaves the effect of FT overexpression driven by meristem-specific KNAT1 gene homolog of Arabidopsis thaliana (Lincoln et al., 1994; Long et al., 1996) on the transcriptomic response during plant development. Our results demonstrated that meristematic FT overexpression generates a phenotype with an early flowering independent of photoperiod when compared with wild type (WT) plants. Arabidopsis FT-overexpressor lines (AtFTOE) did not show significant differences compared with WT lines neither in leaf number nor in rosette diameter up to day 21, when AtFTOE flowered. After this period AtFTOE plants started flower production and no new rosette leaves were produced. Additionally, WT plants continued on vegetative stage up to day 40, producing 12–14 rosette leaves before flowering. Transcriptomic analysis of rosette leaves studied by sequencing Illumina RNA-seq allowed us to determine the differential expression in mature leaf rosette of 3652 genes, being 626 of them up-regulated and 3026 down-regulated. Overexpressed genes related with flowering showed up-regulated transcription factors such as MADS-box that are known as flowering markers in meristem and which overexpression has been related with meristem identity preservation and the transition from vegetative to floral stage. Genes related with sugar transport have shown a higher demand of monosaccharides derived from the hydrolysis of sucrose to glucose and probably fructose, which can also be influenced by reproductive stage of AtFTOE plants. PMID:27154816

  11. RABBIT EARS IS A SECOND-WHORL REPRESSOR OF AGAMOUS THAT MAINTAINS SPATIAL BOUNDARIES IN ARABIDOPSIS FLOWERS

    Science.gov (United States)

    The RABBIT EARS (RBE) gene has been identified as a regulator of petal development in Arabidopsis thaliana. We find that second-whorl petals in rbe mutants can be replaced with staminoid organs, stamens or filaments and that some rbe flowers have increased numbers of sepals and exhibit fusion of sep...

  12. 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

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

    Directory of Open Access Journals (Sweden)

    Wennblom Trevor J

    2011-08-01

    Full Text Available 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

  14. 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...... quite different and distinct biochemical pathways and that laccases might be involved in polymerization of both polysaccharides and monolignols in the Arabidopsis cell wall....

  15. Evidence for five divergent thioredoxin h sequences in Arabidopsis thaliana.

    OpenAIRE

    Rivera-Madrid, R.; Mestres, D; Marinho, P.; Jacquot, J P; Decottignies, P; Miginiac-Maslow, M; Meyer, Y.

    1995-01-01

    Five different clones encoding thioredoxin homologues were isolated from Arabidopsis thaliana cDNA libraries. On the basis of the sequences they encode divergent proteins, but all belong to the cytoplasmic thioredoxins h previously described in higher plants. The five proteins obtained by overexpressing the coding sequences in Escherichia coli present typical thioredoxin activities (NADP(+)-malate dehydrogenase activation and reduction by Arabidopsis thioredoxin reductase) despite the presenc...

  16. 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.

  17. Peculiarities of genital organ formation in Arabidopsis thaliana (L) Heynh. under spaceflight conditions

    Science.gov (United States)

    Kordyum, E. L.; Sytnik, K. M.; Chernyaeva, I. I.

    An experiment was carried out aboard the Salyut 6 research orbital station on Arabidopsis thaliana cultivations. The seeds were sprouted in the Svetoblok 1 device which provides for plant growth in the agar medium under sterile conditions and at 4000 lux illumination. The experimental plants, as well as the controls, reached approximately the same developmental stages: both flowered and began to bear fruit. A microscopic examination of the generative organs in the control and experimental plants shows that in normally formed (by appearance) flower buds and flowers of the experimental plants, as distinct from the controls, there were no fertile elements of the adroecium and gynoecium. Degeneration of the latter occurred at different stages of generative organ development. Possible reasons for this phenomenon in plants grown under weightless conditions are considered.

  18. Gene regulatory variation mediates flowering responses to vernalization along an altitudinal gradient in Arabidopsis.

    Science.gov (United States)

    Suter, Léonie; Rüegg, Marlene; Zemp, Niklaus; Hennig, Lars; Widmer, Alex

    2014-12-01

    Steep environmental gradients provide ideal settings for studies of potentially adaptive phenotypic and genetic variation in plants. The accurate timing of flowering is crucial for reproductive success and is regulated by several pathways, including the vernalization pathway. Among the numerous genes known to enable flowering in response to vernalization, the most prominent is FLOWERING LOCUS C (FLC). FLC and other genes of the vernalization pathway vary extensively among natural populations and are thus candidates for the adaptation of flowering time to environmental gradients such as altitude. We used 15 natural Arabidopsis (Arabidopsis thaliana) genotypes originating from an altitudinal gradient (800-2,700 m above sea level) in the Swiss Alps to test whether flowering time correlated with altitude under different vernalization scenarios. Additionally, we measured the expression of 12 genes of the vernalization pathway and its downstream targets. Flowering time correlated with altitude in a nonlinear manner for vernalized plants. Flowering time could be explained by the expression and regulation of the vernalization pathway, most notably by AGAMOUS LIKE19 (AGL19), FLOWERING LOCUS T (FT), and FLC. The expression of AGL19, FT, and VERNALIZATION INSENSITIVE3 was associated with altitude, and the regulation of MADS AFFECTING FLOWERING2 (MAF2) and MAF3 differed between low- and high-altitude genotypes. In conclusion, we found clinal variation across an altitudinal gradient both in flowering time and the expression and regulation of genes in the flowering time control network, often independent of FLC, suggesting that the timing of flowering may contribute to altitudinal adaptation. PMID:25339407

  19. Cleaning the GenBank Arabidopsis thaliana data set

    DEFF Research Database (Denmark)

    Korning, Peter G.; Hebsgaard, Stefan M.; Rouze, Pierre; Brunak, Søren

    1996-01-01

    Data driven computational biology relies on the large quantities of genomic data stored in international sequence data banks. However, the possibilities are drastically impaired if the stored data is unreliable. During a project aiming to predict splice sites in the dicot Arabidopsis thaliana, we...... extracted a data set from the A. thaliana entries in GenBank. A number of simple `sanity' checks, based on the nature of the data, revealed an alarmingly high error rate. More than 15% of the most important entries extracted did contain erroneous information. In addition, a number of entries had directly...

  20. Cleaning the GenBank Arabidopsis thaliana data set

    DEFF Research Database (Denmark)

    Korning, Peter G.; Hebsgaard, Stefan M.; Rouze, Pierre; Brunak, Søren

    1996-01-01

    extracted a data set from the A. thaliana entries in GenBank. A number of simple `sanity' checks, based on the nature of the data, revealed an alarmingly high error rate. More than 15% of the most important entries extracted did contain erroneous information. In addition, a number of entries had directly......Data driven computational biology relies on the large quantities of genomic data stored in international sequence data banks. However, the possibilities are drastically impaired if the stored data is unreliable. During a project aiming to predict splice sites in the dicot Arabidopsis thaliana, we...

  1. Exploring potential new floral organ morphogenesis genes of Arabidopsis thaliana using systems biology approach.

    Science.gov (United States)

    Xie, Wenchuan; Huang, Junfeng; Liu, Yang; Rao, Jianan; Luo, Da; He, Miao

    2015-01-01

    Flowering is one of the important defining features of angiosperms. The initiation of flower development and the formation of different floral organs are the results of the interplays among numerous genes. But until now, just fewer genes have been found linked with flower development. And the functions of lots of genes of Arabidopsis thaliana are still unknown. Although, the quartet model successfully simplified the ABCDE model to elaborate the molecular mechanism by introducing protein-protein interactions (PPIs). We still don't know much about several important aspects of flower development. So we need to discriminate even more genes involving in the flower development. In this study, we identified seven differentially modules through integrating the weighted gene co-expression network analysis (WGCNA) and Support Vector Machine (SVM) method to analyze co-expression network and PPIs using the public floral and non-floral expression profiles data of Arabidopsis thaliana. Gene set enrichment analysis was used for the functional annotation of the related genes, and some of the hub genes were identified in each module. The potential floral organ morphogenesis genes of two significant modules were integrated with PPI information in order to detail the inherent regulation mechanisms. Finally, the functions of the floral patterning genes were elucidated by combining the PPI and evolutionary information. It was indicated that the sub-networks or complexes, rather than the genes, were the regulation unit of flower development. We found that the most possible potential new genes underlining the floral pattern formation in A. thaliana were FY, CBL2, ZFN3, and AT1G77370; among them, FY, CBL2 acted as an upstream regulator of AP2; ZFN3 activated the flower primordial determining gene AP1 and AP2 by HY5/HYH gene via photo induction possibly. And AT1G77370 exhibited similar function in floral morphogenesis, same as ELF3. It possibly formed a complex between RFC3 and RPS15 in

  2. Exploring potential new floral organ morphogenesis genes of Arabidopsis thaliana using systems biology approach

    Directory of Open Access Journals (Sweden)

    Wenchuan eXie

    2015-10-01

    Full Text Available Flowering is one of the important defining features of angiosperms. The initiation of flower development and the formation of different floral organs are the results of the interplays among numerous genes. But until now, just fewer genes have been found linked with flower development. And the functions of lots of genes of Arabidopsis thaliana are still unknown. Although, the quartet model successfully simplified the ABCDE model to elaborate the molecular mechanism by introducing protein-protein interactions (PPIs. We still don't know much about several important aspects of flower development. So we need to discriminate even more genes involving in the flower development. In this study, we identified seven differentially modules through integrating the weighted gene co-expression network analysis (WGCNA and Support Vector Machine (SVM method to analyze co-expression network and PPIs using the public floral and non-floral expression profiles data of Arabidopsis thaliana. Gene set enrichment analysis was used for the functional annotation of the related genes, and some of the hub genes were identified in each module. The potential floral organ morphogenesis genes of two significant modules were integrated with PPI information in order to detail the inherent regulation mechanisms. Finally, the functions of the floral patterning genes were elucidated by combining the PPI and evolutionary information. It was indicated that the sub-networks or complexes, rather than the genes, were the regulation unit of flower development. We found that the most possible potential new genes underlining the floral pattern formation in A. thaliana were FY, CBL2, ZFN3 and AT1G77370; among them, FY, CBL2 acted as an upstream regulator of AP2; ZFN3 activated the flower primordial determining gene AP1 and AP2 by HY5/HYH gene via photo induction possibly. And AT1G77370 exhibited similar function in floral morphogenesis, same as ELF3. It possibly formed a complex between RFC3

  3. Evolutionary origins of Brassicaceae specific genes in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Keshavaiah Channa

    2011-02-01

    Full Text Available Abstract Background All sequenced genomes contain a proportion of lineage-specific genes, which exhibit no sequence similarity to any genes outside the lineage. Despite their prevalence, the origins and functions of most lineage-specific genes remain largely unknown. As more genomes are sequenced opportunities for understanding evolutionary origins and functions of lineage-specific genes are increasing. Results This study provides a comprehensive analysis of the origins of lineage-specific genes (LSGs in Arabidopsis thaliana that are restricted to the Brassicaceae family. In this study, lineage-specific genes within the nuclear (1761 genes and mitochondrial (28 genes genomes are identified. The evolutionary origins of two thirds of the lineage-specific genes within the Arabidopsis thaliana genome are also identified. Almost a quarter of lineage-specific genes originate from non-lineage-specific paralogs, while the origins of ~10% of lineage-specific genes are partly derived from DNA exapted from transposable elements (twice the proportion observed for non-lineage-specific genes. Lineage-specific genes are also enriched in genes that have overlapping CDS, which is consistent with such novel genes arising from overprinting. Over half of the subset of the 958 lineage-specific genes found only in Arabidopsis thaliana have alignments to intergenic regions in Arabidopsis lyrata, consistent with either de novo origination or differential gene loss and retention, with both evolutionary scenarios explaining the lineage-specific status of these genes. A smaller number of lineage-specific genes with an incomplete open reading frame across different Arabidopsis thaliana accessions are further identified as accession-specific genes, most likely of recent origin in Arabidopsis thaliana. Putative de novo origination for two of the Arabidopsis thaliana-only genes is identified via additional sequencing across accessions of Arabidopsis thaliana and closely

  4. 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.

  5. 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...... of these amino acids for targeted stress-tolerant enzyme bioengineering.......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...

  6. 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. PMID:20889713

  7. Inheritance beyond plain heritability : variance controlling genes in Arabidopsis thaliana

    OpenAIRE

    Xia Shen; Mats Pettersson; Lars Rönnegård; Örjan Carlborg

    2012-01-01

    Author Summary The most well-studied effects of genes are those leading to different phenotypic means for alternative genotypes. A less well-explored type of genetic control is that resulting in a heterogeneity in variance between genotypes. Here, we reanalyze a publicly available Arabidopsis thaliana GWAS dataset to detect genetic effects on the variance heterogeneity, and our results indicate that the environmental variance is under extensive genetic control by a large number of variance-co...

  8. CAMTA 1 regulates drought responses in Arabidopsis thaliana

    OpenAIRE

    Pandey, Neha; Ranjan, Alok; Pant, Poonam; Tripathi, Rajiv K; Ateek, Farha; Pandey, Haushilla P; Patre, Uday V; Sawant, Samir V

    2013-01-01

    Background Transcription factors (TF) play a crucial role in regulating gene expression and are fit to regulate diverse cellular processes by interacting with other proteins. A TF named calmodulin binding transcription activator (CAMTA) was identified in Arabidopsis thaliana (AtCAMTA1-6). To explore the role of CAMTA1 in drought response, the phenotypic differences and gene expression was studied between camta1 and Col-0 under drought condition. Results In camta1, root development was abolish...

  9. Identification of a novel flavonoid glycoside sulfotransferase in Arabidopsis thaliana

    OpenAIRE

    Hashiguchi, Takuyu; Sakakibara, Yoichi; Shimohira, Takehiko; Kurogi, Katsuhisa; Yamasaki, Masao; Nishiyama, Kazuo; Akashi, Ryo; Liu, Ming-Cheh; Suiko, Masahito

    2013-01-01

    The discovery of sulfated flavonoids in plants suggests that sulfation may play a regulatory role in the physiological functions of flavonoids. Sulfation of flavonoids is mediated by cytosolic sulfotransferases (SULTs), which utilize 3′-phosphoadenosine 5′-phosphosulfate (PAPS) as the sulfate donor. A novel SULT from Arabidopsis thaliana, designated AtSULT202B7 (AGI code: At1g13420), was cloned and expressed in Escherichia coli. Using various compounds as potential substrates, we demonstrated...

  10. Segmenting the sepal and shoot apical meristem of Arabidopsis thaliana

    OpenAIRE

    Cunha, Alexandre L.; Roeder, Adrienne H. K.; Meyerowitz, Elliot M.

    2010-01-01

    We present methods for segmenting the sepal and shoot apical meristem of the Arabidopsis thaliana plant. We propose a mathematical morphology pipeline and a modified numerical scheme for the active contours without edges algorithm to extract the geometry and topology of plant cells imaged using confocal laser scanning microscopy. We demonstrate our methods in typical images used in the studies of cell endoreduplication and hormone transport and show that in practice they produce highly accura...

  11. Functional genetics of intraspecific ecological interactions in Arabidopsis thaliana

    OpenAIRE

    Wolf, Jason B.; Mutic, Joshua J.; Kover, Paula X.

    2011-01-01

    Studying the genetic basis of traits involved in ecological interactions is a fundamental part of elucidating the connections between evolutionary and ecological processes. Such knowledge allows one to link genetic models of trait evolution with ecological models describing interactions within and between species. Previous work has shown that connections between genetic and ecological processes in Arabidopsis thaliana may be mediated by the fact that quantitative trait loci (QTL) with ‘direct...

  12. 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.

  13. pATsi: Paralogs and Singleton Genes from Arabidopsis thaliana

    Science.gov (United States)

    Ambrosino, Luca; Bostan, Hamed; di Salle, Pasquale; Sangiovanni, Mara; Vigilante, Alessandra; Chiusano, Maria L.

    2016-01-01

    Arabidopsis thaliana is widely accepted as a model species in plant biology. Its genome, due to its small size and diploidy, was the first to be sequenced among plants, making this species also a reference for plant comparative genomics. Nevertheless, the evolutionary mechanisms that shaped the Arabidopsis genome are still controversial. Indeed, duplications, translocations, inversions, and gene loss events that contributed to the current organization are difficult to be traced. A reliable identification of paralogs and single-copy genes is essential to understand these mechanisms. Therefore, we implemented a dedicated pipeline to identify paralog genes and classify single-copy genes into opportune categories. PATsi, a web-accessible database, was organized to allow the straightforward access to the paralogs organized into networks and to the classification of single-copy genes. This permits to efficiently explore the gene collection of Arabidopsis for evolutionary investigations and comparative genomics. PMID:26792975

  14. Phosphorylation of plastoglobular proteins in Arabidopsis thaliana.

    Science.gov (United States)

    Lohscheider, Jens N; Friso, Giulia; van Wijk, Klaas J

    2016-06-01

    Plastoglobules (PGs) are plastid lipid-protein particles with a small specialized proteome and metabolome. Among the 30 core PG proteins are six proteins of the ancient ABC1 atypical kinase (ABC1K) family and their locations in an Arabidopsis mRNA-based co-expression network suggested central regulatory roles. To identify candidate ABC1K targets and a possible ABC1K hierarchical phosphorylation network within the chloroplast PG proteome, we searched Arabidopsis phosphoproteomics data from publicly available sources. Evaluation of underlying spectra and/or associated information was challenging for a variety of reasons, but supported pSer sites and a few pThr sites in nine PG proteins, including five FIBRILLINS. PG phosphorylation motifs are discussed in the context of possible responsible kinases. The challenges of collection and evaluation of published Arabidopsis phosphorylation data are discussed, illustrating the importance of deposition of all mass spectrometry data in well-organized repositories such as PRIDE and ProteomeXchange. This study provides a starting point for experimental testing of phosho-sites in PG proteins and also suggests that phosphoproteomics studies specifically designed toward the PG proteome and its ABC1K are needed to understand phosphorylation networks in these specialized particles. PMID:26962209

  15. Gene coexpression analysis reveals complex metabolism of the monoterpene alcohol linalool in Arabidopsis flowers.

    OpenAIRE

    Ginglinger, J.-F.; Boachon, B.; Hofer, R.; Paetz, C.; Kollner, T. G.; Miesch, L.; Lugan, R.; Baltenweck, R.; Mutterer, J.; Ullmann, P.; Beran, F.; Claudel, P.; Verstappen, F.; Fischer, M. J. C.; Karst, F

    2013-01-01

    The cytochrome P450 family encompasses the largest family of enzymes in plant metabolism, and the functions of many of its members in Arabidopsis thaliana are still unknown. Gene coexpression analysis pointed to two P450s that were coexpressed with two monoterpene synthases in flowers and were thus predicted to be involved in monoterpenoid metabolism. We show that all four selected genes, the two terpene synthases (TPS10 and TPS14) and the two cytochrome P450s (CYP71B31 and CYP76C3), are simu...

  16. 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.

  17. 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.

  18. 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. PMID:27058920

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

    OpenAIRE

    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 gene balance control, gene expression and regulation, and may affect the plant’s phenotype. Moreover, chromosome changes, in particular polyploidy, inversions and translocations play a signif...

  20. A reference map of the Arabidopsis thaliana mature pollen proteome

    International Nuclear Information System (INIS)

    The male gametophyte (or pollen) plays an obligatory role during sexual reproduction of higher plants. The extremely reduced complexity of this organ renders pollen a valuable experimental system for studying fundamental aspects of plant biology such as cell fate determination, cell-cell interactions, cell polarity, and tip-growth. Here, we present the first reference map of the mature pollen proteome of the dicotyledonous model plant species, Arabidopsis thaliana. Based on two-dimensional gel electrophoresis, matrix-assisted laser desorption/ionization time-of-flight, and electrospray quadrupole time-of-flight mass spectrometry, we reproducibly identified 121 different proteins in 145 individual spots. The presence, subcellular localization, and functional classification of the identified proteins are discussed in relation to the pollen transcriptome and the full protein complement encoded by the nuclear Arabidopsis genome

  1. Mutations in leaf starch metabolism modulate the diurnal root growth profiles of Arabidopsis thaliana

    OpenAIRE

    Yazdanbakhsh, Nima; FISAHN, JOACHIM

    2011-01-01

    Roots of Arabidopsis thaliana exhibit stable diurnal growth profiles that are controlled by the circadian clock. Here we describe the effects of mutations in leaf starch metabolism on the diurnal root growth characteristics of Arabidopsis thaliana. High temporal and spatial resolution video imaging was performed to quantify the growth kinetics of Arabidopsis wild-type as well as pgm, sex1, mex1, dpe1 and dpe2 starch metabolism mutants grown in three different photoperiods. As a result, root g...

  2. Chromosomal rearrangement in autotetraploid plants of Arabidopsis thaliana.

    Science.gov (United States)

    Weiss, H; Maluszynska, J

    2000-01-01

    Recent development of cytogenetic techniques has facilitated significant progress in Arabidopsis thaliana karyotype studies. Double-target FISH with rRNA genes provides makers that allow individual chromosome in the genome to be distinguished. Those studies have revealed that the number and position of rDNA loci is ecotype-specific. Arabidopsis is believed to be a true diploid (x = 5) with numerous ecotypes (accessions) and only a very few natural polyploid populations reported. Few studies were undertaken to induce polyploidy in Arabidopsis, however none of those gave the cytogenetic characteristics of polyploid plants. Our analysis of chromosome pairing of colchicine-induced autotetraploid Arabidopsis (Wilna ecotype) revealed preferential bivalent pairing in PMCs (pollen mother cells). In order to attempt to explain this phenomenon, first of all more detailed cytogenetic studies of autopolyploid plants have been undertaken. The localization of 45S and 5S rDNA loci in the diploid and autotetraploid plants revealed that Wilna ecotypes belongs to the group of Arabidopsis accessions with only two 5S rDNA loci present in a genome. Furthermore, the rearrangement of 45S rDNA locus in autopolyploid, when compared to the diploid plants of the same ecotype, was revealed. These results are interesting also in the context of the recently emphasised role of polyploidy in plant evolution and speciation. Arabidopsis, despite having small chromosomes, is a good system to study chromosome behaviour in relation to diploidization of autopolyploids and to evaluate the degree of chromosomal rearrangements during this process. PMID:11433970

  3. Piriformospora indica Stimulates Root Metabolism of Arabidopsis thaliana.

    Science.gov (United States)

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

    2016-01-01

    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. PMID:27399695

  4. Arabidopsis CDS blastp result: AK058419 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK058419 001-015-D06 At4g16280.3 flowering time ... control protein / FCA gamma (FCA) identical to S ... P|O04425 Flowering time ... control protein FCA {Arabidopsis thaliana}; four a ...

  5. Arabidopsis CDS blastp result: AK073225 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK073225 J033023C04 At4g16280.3 flowering time ... control protein / FCA gamma (FCA) identical to SP ... |O04425 Flowering time ... control protein FCA {Arabidopsis thaliana}; four a ...

  6. 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.

  7. 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.

  8. Cerium toxicity, uptake and translocation in Arabidopsis thaliana seedlings

    Institute of Scientific and Technical Information of China (English)

    WANG Xue; LIN Yousheng; LIU Dongwu; XU Hengjian; LIU Tao; ZHAO Fengyun

    2012-01-01

    Arabidopsis thaliana seedlings were cultivated in 0-500 μmol/L of extraneous cerium (Ce) for 7 d to investigate the toxicity,uptake and translocation of rare earth elements (REEs).The results showed that Ce could be largely absorbed by the roots of A.thaliana and translocated to the shoots.But the uptake rates of Ce by the roots were much higher than the translocation rates from roots to shoots.Ultrastructural analysis revealed that Ce was mainly distributed on the cell wall.At higher concentration,Ce could also enter cell,destroy the ultrastructure of cells and disturb the intrinsic balance of nutrient elements of A.thaliana.Addition of Ce (50-500 μmol/L) to the culture medium significantly inhibited the elongation of primary roots,decreased chlorophyll content,rosette diameter and fresh mass of plants.The damage increased with the increase of Ce concentration in culture medium,although primary root elongation,chlorophyll content,and rosette diameter were stimulated by relatively low concentration (0.5 μmol/L) of Ce.Thus,it is speculated that REEs may become a new type contamination if we don't well control the release of REEs into the environment.

  9. Sample Preparation of Arabidopsis thaliana Shoot Apices for Expression Studies of Photoperiod-Induced Genes.

    Science.gov (United States)

    Andrés, Fernando; Torti, Stefano; Vincent, Coral; Coupland, George

    2016-01-01

    Plants produce new organs from a population of pluripotent cells which are located in specific tissues called meristems. One of these meristems, the shoot apical meristem (SAM), gives rise to leaves during the vegetative phase and flowers during the reproductive phase. The transition from vegetative SAM to an inflorescence meristem (IM) is a dramatic developmental switch, which has been particularly well studied in the model species Arabidopsis thaliana. This developmental switch is controlled by multiple environmental signals such as day length (or photoperiod), and it is accompanied by changes in expression of hundreds of genes. A major interest in plant biology is to identify and characterize those genes which are regulated in the stem cells of the SAM in response to the photoperiodic signals. In this sense, techniques such as RNA in situ hybridization (RNA ISH) have been very successfully employed to detect the temporal and spatial expression patterns of genes in the SAM. This method can be specifically optimized for photoperiodic-flowering studies. In this chapter, we describe improved methods to generate plant material and histological samples to be combined with RNA ISH in flowering-related studies. PMID:26867617

  10. 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.

  11. A glycolate dehydrogenase in the mitochondria of Arabidopsis thaliana.

    Science.gov (United States)

    Bari, Rafijul; Kebeish, Rashad; Kalamajka, Rainer; Rademacher, Thomas; Peterhänsel, Christoph

    2004-03-01

    The fixation of molecular O2 by the oxygenase activity of Rubisco leads to the formation of phosphoglycolate in the chloroplast that is further metabolized in the process of photorespiration. The initial step of this pathway is the oxidation of glycolate to glyoxylate. Whereas in higher plants this reaction takes place in peroxisomes and is dependent on oxygen as a co-factor, most algae oxidize glycolate in the mitochondria using organic co-factors. The identification and characterization of a novel glycolate dehydrogenase in Arabidopsis thaliana is reported here. The enzyme is dependent on organic co-factors and resembles algal glycolate dehydrogenases in its enzymatic properties. Mutants of E. coli incapable of glycolate oxidation can be complemented by overexpression of the Arabidopsis open reading frame. The corresponding RNA accumulates preferentially in illuminated leaves, but was also found in other tissues investigated. A fusion of the N-terminal part of the Arabidopsis glycolate dehydrogenase to red fluorescent protein accumulates in mitochondria when overexpressed in the homologous system. Based on these results it is proposed that the basic photorespiratory system of algae is conserved in higher plants. PMID:14966218

  12. Repression of Lateral Organ Boundary Genes by PENNYWISE and POUND-FOOLISH Is Essential for Meristem Maintenance and Flowering in Arabidopsis.

    Science.gov (United States)

    Khan, Madiha; Ragni, Laura; Tabb, Paul; Salasini, Brenda C; Chatfield, Steven; Datla, Raju; Lock, John; Kuai, Xiahezi; Després, Charles; Proveniers, Marcel; Yongguo, Cao; Xiang, Daoquan; Morin, Halima; Rullière, Jean-Pierre; Citerne, Sylvie; Hepworth, Shelley R; Pautot, Véronique

    2015-11-01

    In the model plant Arabidopsis (Arabidopsis thaliana), endogenous and environmental signals acting on the shoot apical meristem cause acquisition of inflorescence meristem fate. This results in changed patterns of aerial development seen as the transition from making leaves to the production of flowers separated by elongated internodes. Two related BEL1-like homeobox genes, PENNYWISE (PNY) and POUND-FOOLISH (PNF), fulfill this transition. Loss of function of these genes impairs stem cell maintenance and blocks internode elongation and flowering. We show here that pny pnf apices misexpress lateral organ boundary genes BLADE-ON-PETIOLE1/2 (BOP1/2) and KNOTTED-LIKE FROM ARABIDOPSIS THALIANA6 (KNAT6) together with ARABIDOPSIS THALIANA HOMEOBOX GENE1 (ATH1). Inactivation of genes in this module fully rescues pny pnf defects. We further show that BOP1 directly activates ATH1, whereas activation of KNAT6 is indirect. The pny pnf restoration correlates with renewed accumulation of transcripts conferring floral meristem identity, including FD, SQUAMOSA PROMOTER-BINDING PROTEIN LIKE genes, LEAFY, and APETALA1. To gain insight into how this module blocks flowering, we analyzed the transcriptome of BOP1-overexpressing plants. Our data suggest a central role for the microRNA156-SQUAMOSA PROMOTER BINDING PROTEIN-LIKE-microRNA172 module in integrating stress signals conferred in part by promotion of jasmonic acid biosynthesis. These data reveal a potential mechanism by which repression of lateral organ boundary genes by PNY-PNF is essential for flowering. PMID:26417006

  13. Mutagenesis of Arabidopsis Thaliana by N+ Ion Implantation

    Science.gov (United States)

    Zhang, Genfa; Shi, Xiaoming; Nie, Yanli; Jiang, Shan; Zhou, Hongyu; Lu, Ting; Zhang, Jun

    2006-05-01

    Ion implantation, as a new biophysically mutagenic technique, has shown a great potential for crop breeding. By analyzing polymorphisms of genomic DNA through RAPD-based DNA analysis, we compared the frequency and efficiency of somatic and germ-line mutations of Arabidopsis thaliana treated with N+ ion implantation and γ-rays radiation. Our data support the following conclusions: (1) N+ ion implantation can induce a much wider spectrum of mutations than γ-rays radiation does; (2) Unlike the linear correlation between the doses and their effect in γ-rays radiation, the dose-effect correlation in N+ ion implantation is nonlinear; (3) Like γ-rays radiation, both somatic and germ-line mutations could be induced by N+ ion implantation; and (4) RAPD deletion patterns are usually seen in N+ ion implantation induced mutation.

  14. Human intrinsic factor expressed in the plant Arabidopsis thaliana

    DEFF Research Database (Denmark)

    Fedosov, Sergey N; Laursen, Niels B; Nexø, Ebba;

    2003-01-01

    contamination by other B12 binders. We tested the use of recombinant plants for large-scale production of pathogen-free human recombinant IF. Human IF was successfully expressed in the recombinant plant Arabidopsis thaliana. Extract from fresh plants possessed high B12-binding capacity corresponding to 70 mg IF...... per 1 kg wet weight. The dried plants still retained 60% of the IF activity. The purified IF preparation consisted of a 50-kDa glycosylated protein with the N-terminal sequence of mature IF. Approximately one-third of the protein was cleaved at the internal site em leader PSNP downward arrow GPGP. The...... recombinant IF and gastric IF were alike, as was the interaction of recombinant and native IF with the specific receptor cubilin. The data presented show that recombinant plants have a great potential as a large-scale source of human IF for analytical and therapeutic purposes....

  15. Arabidopsis thaliana is an asymptomatic host of Alfalfa mosaic virus.

    Science.gov (United States)

    Balasubramaniam, Muthukumar; Ibrahim, Amr; Kim, Bong-Suk; Loesch-Fries, L Sue

    2006-11-01

    The susceptibility of Arabidopsis thaliana ecotypes to infection by Alfalfa mosaic virus (AMV) was evaluated. Thirty-nine ecotypes supported both local and systemic infection, 26 ecotypes supported only local infection, and three ecotypes could not be infected. No obvious symptoms characteristic of virus infection developed on the susceptible ecotypes under standard conditions of culture. Parameters of AMV infection were characterized in ecotype Col-0, which supported systemic infection and accumulated higher levels of AMV than the symptomatic host Nicotiana tabacum. The formation of infectious AMV particles in infected Col-0 was confirmed by infectivity assays on a hypersensitive host and by electron microscopy of purified virions. Replication and transcription of AMV was confirmed by de novo synthesis of AMV subgenomic RNA in Col-0 protoplasts transfected with AMV RNA or plasmids harboring AMV cDNAs. PMID:16875753

  16. CuO Nanoparticle Interaction with Arabidopsis thaliana: Toxicity, Parent-Progeny Transfer, and Gene Expression.

    Science.gov (United States)

    Wang, Zhenyu; Xu, Lina; Zhao, Jian; Wang, Xiangke; White, Jason C; Xing, Baoshan

    2016-06-01

    CuO nanoparticles (NPs) (20, 50 mg L(-1)) inhibited seedling growth of different Arabidopsis thaliana ecotypes (Col-0, Bay-0, and Ws-2), as well as the germination of their pollens and harvested seeds. For most of growth parameters (e.g., biomass, relative growth rate, root morphology change), Col-0 was the more sensitive ecotype to CuO NPs compared to Bay-0 and Ws-2. Equivalent Cu(2+) ions and CuO bulk particles had no effect on Arabidopsis growth. After CuO NPs (50 mg L(-1)) exposure, Cu was detected in the roots, leaves, flowers and harvested seeds of Arabidopsis, and its contents were significantly higher than that in CuO bulk particles (50 mg L(-1)) and Cu(2+) ions (0.15 mg L(-1)) treatments. Based on X-ray absorption near-edge spectroscopy analysis (XANES), Cu in the harvested seeds was confirmed as being mainly in the form of CuO (88.8%), which is the first observation on the presence of CuO NPs in the plant progeny. Moreover, after CuO NPs exposure, two differentially expressed genes (C-1 and C-3) that regulated root growth and reactive oxygen species generation were identified, which correlated well with the physiological root inhibition and oxidative stress data. This current study provides direct evidence for the negative effects of CuO NPs on Arabidopsis, including accumulation and parent-progeny transfer of the particles, which may have significant implications with regard to the risk of NPs to food safety and security. PMID:27226046

  17. Nuclear micro-probe analysis of Arabidopsis thaliana leaves

    International Nuclear Information System (INIS)

    Phytoremediation is a cost-effective plant-based approach for remediation of soils and waters which takes advantage of the remarkable ability of some plants to concentrate elements and compounds from the environment and to metabolize various molecules in their tissues, such as toxic heavy metals and organic pollutants. Nowadays, phytoremediation technology is becoming of paramount importance when environmental decontamination is concerned, due to the emerging knowledge of its physiological and molecular mechanisms and the new biological and engineering strategies designed to optimize and improve it. In addition, the feasibility of using plants for environmental cleanup has been confirmed by many different trials around the world. Arabidopsis thaliana plants can be used for basic studies to improve the technology on phytoremediation. Making use of nuclear microscopy techniques, in this paper we study leaves of wild type and transgenic A. thaliana plants grown in a cadmium-rich environment under different conditions. Micro-PIXE, RBS and SEM analyses, performed on the scanning proton micro-probe at the CNA in Seville (Spain), prove that cadmium is preferentially sequestered in the central region of epidermal trichome and allow comparing the effects of genetic modifications

  18. Nuclear micro-probe analysis of Arabidopsis thaliana leaves

    Science.gov (United States)

    Ager, F. J.; Ynsa, M. D.; Domínguez-Solís, J. R.; López-Martín, M. C.; Gotor, C.; Romero, L. C.

    2003-09-01

    Phytoremediation is a cost-effective plant-based approach for remediation of soils and waters which takes advantage of the remarkable ability of some plants to concentrate elements and compounds from the environment and to metabolize various molecules in their tissues, such as toxic heavy metals and organic pollutants. Nowadays, phytoremediation technology is becoming of paramount importance when environmental decontamination is concerned, due to the emerging knowledge of its physiological and molecular mechanisms and the new biological and engineering strategies designed to optimize and improve it. In addition, the feasibility of using plants for environmental cleanup has been confirmed by many different trials around the world. Arabidopsis thaliana plants can be used for basic studies to improve the technology on phytoremediation. Making use of nuclear microscopy techniques, in this paper we study leaves of wild type and transgenic A. thaliana plants grown in a cadmium-rich environment under different conditions. Micro-PIXE, RBS and SEM analyses, performed on the scanning proton micro-probe at the CNA in Seville (Spain), prove that cadmium is preferentially sequestered in the central region of epidermal trichome and allow comparing the effects of genetic modifications.

  19. 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.

  20. Regeneration from leaf protoplasts of Arabidopsis thaliana ecotype estland.

    Science.gov (United States)

    Gandhi, R; Khurana, P

    2001-07-01

    Protoplasts (2 x 10(7)/g fresh wt) were isolated from leaves of A. thaliana ecotype estland, with a viability of more than 90%. Protoplasts cultured in calcium alginate beads or layers showed division while culture in liquid or agarose beads failed to elicit any division. Effect of culture density showed highest frequency of division occurring at 5 x 10(5) while no division was seen when cultured at a density of 5 x 10(4). Culture in MS medium resulted in higher division frequency and better sustenance of microcolonies as compared to B5 medium. Under optimized conditions, macrocolonies were formed at a frequency of 1.8%. Shoot regeneration was seen in 50% of microcalli transferred to shoot induction medium for regeneration. Shoots were rooted and plantlets transferred to pots. The plants produced flowers and were fertile. PMID:12019766

  1. Arabidopsis thaliana DNA gyrase is targeted to chloroplasts and mitochondria

    Science.gov (United States)

    Wall, Melisa K.; Mitchenall, Lesley A.; Maxwell, Anthony

    2004-01-01

    DNA gyrase is the bacterial DNA topoisomerase (topo) that supercoils DNA by using the free energy of ATP hydrolysis. The enzyme, an A2B2 tetramer encoded by the gyrA and gyrB genes, catalyses topological changes in DNA during replication and transcription, and is the only topo that is able to introduce negative supercoils. Gyrase is essential in bacteria and apparently absent from eukaryotes and is, consequently, an important target for antibacterial agents (e.g., quinolones and coumarins). We have identified four putative gyrase genes in the model plant Arabidopsis thaliana; one gyrA and three gyrB homologues. DNA gyrase protein A (GyrA) has a dual translational initiation site targeting the mature protein to both chloroplasts and mitochondria, and there are individual targeting sequences for two of the DNA gyrase protein B (GyrB) homologues. N-terminal fusions of the organellar targeting sequences to GFPs support the hypothesis that one enzyme is targeted to the chloroplast and another to the mitochondrion, which correlates with supercoiling activity in isolated organelles. Treatment of seedlings and cultured cells with gyrase-specific drugs leads to growth inhibition. Knockout of A. thaliana gyrA is embryo-lethal whereas knockouts in the gyrB genes lead to seedling-lethal phenotypes or severely stunted growth and development. The A. thaliana genes have been cloned in Escherichia coli and found to complement gyrase temperature-sensitive strains. This report confirms the existence of DNA gyrase in eukaryotes and has important implications for drug targeting, organelle replication, and the evolution of topos in plants. PMID:15136745

  2. Mediator subunit18 controls flowering time and floral organ identity in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Zhengui Zheng

    Full Text Available Mediator is a conserved multi-protein complex that plays an important role in regulating transcription by mediating interactions between transcriptional activator proteins and RNA polymerase II. Much evidence exists that Mediator plays a constitutive role in the transcription of all genes transcribed by RNA polymerase II. However, evidence is mounting that specific Mediator subunits may control the developmental regulation of specific subsets of RNA polymerase II-dependent genes. Although the Mediator complex has been extensively studied in yeast and mammals, only a few reports on Mediator function in flowering time control of plants, little is known about Mediator function in floral organ identity. Here we show that in Arabidopsis thaliana, MEDIATOR SUBUNIT 18 (MED18 affects flowering time and floral organ formation through FLOWERING LOCUS C (FLC and AGAMOUS (AG. A MED18 loss-of-function mutant showed a remarkable syndrome of later flowering and altered floral organ number. We show that FLC and AG mRNA levels and AG expression patterns are altered in the mutant. Our results support parallels between the regulation of FLC and AG and demonstrate a developmental role for Mediator in plants.

  3. 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.

  4. Metabolic footprint of epiphytic bacteria on Arabidopsis thaliana leaves.

    Science.gov (United States)

    Ryffel, Florian; Helfrich, Eric Jn; Kiefer, Patrick; Peyriga, Lindsay; Portais, Jean-Charles; Piel, Jörn; Vorholt, Julia A

    2016-03-01

    The phyllosphere, which is defined as the parts of terrestrial plants above the ground, is a large habitat for different microorganisms that show a high extent of adaption to their environment. A number of hypotheses were generated by culture-independent functional genomics studies to explain the competitiveness of specialized bacteria in the phyllosphere. In contrast, in situ data at the metabolome level as a function of bacterial colonization are lacking. Here, we aimed to obtain new insights into the metabolic interplay between host and epiphytes upon colonization of Arabidopsis thaliana leaves in a controlled laboratory setting using environmental metabolomics approaches. Quantitative nuclear magnetic resonance (NMR) and imaging high-resolution mass spectrometry (IMS) methods were used to identify Arabidopsis leaf surface compounds and their possible involvement in the epiphytic lifestyle by relative changes in compound pools. The dominant carbohydrates on the leaf surfaces were sucrose, fructose and glucose. These sugars were significantly and specifically altered after epiphytic leaf colonization by the organoheterotroph Sphingomonas melonis or the phytopathogen Pseudomonas syringae pv. tomato, but only to a minor extent by the methylotroph Methylobacterium extorquens. In addition to carbohydrates, IMS revealed surprising alterations in arginine metabolism and phytoalexin biosynthesis that were dependent on the presence of bacteria, which might reflect the consequences of bacterial activity and the recognition of not only pathogens but also commensals by the plant. These results highlight the power of environmental metabolomics to aid in elucidating the molecular basis underlying plant-epiphyte interactions in situ. PMID:26305156

  5. Life cycle of Arabidopsis thaliana under microgravity condition in the International Space Station Kibo module

    Science.gov (United States)

    Karahara, Ichirou; Soga, Kouichi; Hoson, Takayuki; Kamisaka, Seiichiro; Yano, Sachiko; Shimazu, Toru; Tamaoki, Daisuke; Tanigaki, Fumiaki; Kasahara, Haruo; Yashiro, Umi; Suto, Takamichi; Yamaguchi, Takashi; Kasahara, Hirokazu

    2012-07-01

    Gravity is an important environmental factors for growth and development of plants throughout their life cycle. We have designed an experiment, which is called Space Seed, to examine the effects of microgravity on the seed to seed life cycle of plants. We have carried out this experiment using a newly developed apparatus, which is called the Plant Experiment Unit (PEU) and installed in the Cell Biology Experiment Facility (CBEF) onboard International Space Station (ISS). The CBEF is equipped with a turntable generating artificial gravity to perform 1-G control experiment as well as micro-G experiment on board. Arabidopsis thaliana seeds sown on dry rockwool in PEUs were transported from Kennedy Space Center to the ISS Kibo module by Space Shuttle Discovery in STS-128 mission. This experiment was started on Sep. 10, 2009 and terminated on Nov. 11, 2009. Arabidopsis seeds successfully germinated, and the plants passed through both vegetative and reproductive processes, such as formation of rosette leaves, bolting of inflorescence stems, flowering, formation of siliques and seeds. Vegetative and reproductive growth were compared among micro-G plants, 1-G control, and the ground control.

  6. Crystallization and preliminary X-ray analysis of immunophilin-like FKBP42 from Arabidopsis thaliana

    International Nuclear Information System (INIS)

    The crystallization of FKBP42, a multi-domain member of the FK506-binding protein family, from the plant A. thaliana is reported. Two fragments of FKBP42 from Arabidopsis thaliana covering differing lengths of the molecule have been expressed, purified and crystallized. For each construct, crystals belonging to two different space groups were obtained and subjected to preliminary X-ray analysis

  7. 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 ¿M

  8. Inferring the Brassica rapa interactome using protein-protein interaction data from Arabidopsis thaliana

    OpenAIRE

    Jianhua eYang; Kim eOsman; Mudassar eIqbal; Stekel, Dov J; Zewei eLuo; Armstrong, Susan J; Franklin, F. Chris H.

    2013-01-01

    Following successful completion of the Brassica rapa sequencing project, the next step is to investigate functions of individual genes/proteins. For Arabidopsis thaliana, large amounts of protein-protein interaction (PPI) data are available from the major PPI databases. It is known that Brassica crop species are closely related to A. thaliana. This provides an opportunity to infer the B. rapa interactome using PPI data available from A. thaliana. In this paper, we present an inferred B. rapa ...

  9. Inferring the Brassica rapa Interactome Using Protein–Protein Interaction Data from Arabidopsis thaliana

    OpenAIRE

    Yang, Jianhua; Osman, Kim; Iqbal, Mudassar; Stekel, Dov J; Luo, Zewei; Armstrong, Susan J; Franklin, F. Chris H.

    2013-01-01

    Following successful completion of the Brassica rapa sequencing project, the next step is to investigate functions of individual genes/proteins. For Arabidopsis thaliana, large amounts of protein–protein interaction (PPI) data are available from the major PPI databases (DBs). It is known that Brassica crop species are closely related to A. thaliana. This provides an opportunity to infer the B. rapa interactome using PPI data available from A. thaliana. In this paper, we present an inferred B....

  10. The homeotic gene APETALA3 of Arabidopsis thaliana encodes a MADS box and is expressed in petals and stamens.

    Science.gov (United States)

    Jack, T; Brockman, L L; Meyerowitz, E M

    1992-02-21

    Mutations in the APETALA3 (AP3) gene of A. thaliana result in homeotic transformations of petals to sepals and stamens to carpels. We have cloned the AP3 gene from Arabidopsis based on its homology to the homeotic flower gene deficiens (DEFA) from the distantly related plant Antirrhinum majus. The sequence of four ap3 mutant alleles and genetic mapping analysis prove that the DEFA homolog is AP3. Like several other plant homeotic genes, the AP3 gene contains a MADS box and likely acts as a transcription factor. The region-specific spatial expression pattern of AP3 rules out certain types of sequential models of flower development and argues in favor of a spatial model based on positional information. Since DEFA and AP3 have very similar protein products, mutant phenotypes, and spatial expression patterns, it is likely that these genes are cognate homologs. PMID:1346756

  11. Genome-Wide Association Mapping in Arabidopsis Identifies Previously Known Flowering Time and Pathogen Resistance Genes.

    Directory of Open Access Journals (Sweden)

    2005-11-01

    Full Text Available There is currently tremendous interest in the possibility of using genome-wide association mapping to identify genes responsible for natural variation, particularly for human disease susceptibility. The model plant Arabidopsis thaliana is in many ways an ideal candidate for such studies, because it is a highly selfing hermaphrodite. As a result, the species largely exists as a collection of naturally occurring inbred lines, or accessions, which can be genotyped once and phenotyped repeatedly. Furthermore, linkage disequilibrium in such a species will be much more extensive than in a comparable outcrossing species. We tested the feasibility of genome-wide association mapping in A. thaliana by searching for associations with flowering time and pathogen resistance in a sample of 95 accessions for which genome-wide polymorphism data were available. In spite of an extremely high rate of false positives due to population structure, we were able to identify known major genes for all phenotypes tested, thus demonstrating the potential of genome-wide association mapping in A. thaliana and other species with similar patterns of variation. The rate of false positives differed strongly between traits, with more clinal traits showing the highest rate. However, the false positive rates were always substantial regardless of the trait, highlighting the necessity of an appropriate genomic control in association studies.

  12. Genome-wide association mapping in Arabidopsis identifies previously known flowering time and pathogen resistance genes.

    Directory of Open Access Journals (Sweden)

    María José Aranzana

    2005-11-01

    Full Text Available There is currently tremendous interest in the possibility of using genome-wide association mapping to identify genes responsible for natural variation, particularly for human disease susceptibility. The model plant Arabidopsis thaliana is in many ways an ideal candidate for such studies, because it is a highly selfing hermaphrodite. As a result, the species largely exists as a collection of naturally occurring inbred lines, or accessions, which can be genotyped once and phenotyped repeatedly. Furthermore, linkage disequilibrium in such a species will be much more extensive than in a comparable outcrossing species. We tested the feasibility of genome-wide association mapping in A. thaliana by searching for associations with flowering time and pathogen resistance in a sample of 95 accessions for which genome-wide polymorphism data were available. In spite of an extremely high rate of false positives due to population structure, we were able to identify known major genes for all phenotypes tested, thus demonstrating the potential of genome-wide association mapping in A. thaliana and other species with similar patterns of variation. The rate of false positives differed strongly between traits, with more clinal traits showing the highest rate. However, the false positive rates were always substantial regardless of the trait, highlighting the necessity of an appropriate genomic control in association studies.

  13. Phenotypic diversity and altered environmental plasticity in Arabidopsis thaliana with reduced Hsp90 levels.

    Directory of Open Access Journals (Sweden)

    Todd A Sangster

    Full Text Available The molecular chaperone HSP90 aids the maturation of a diverse but select set of metastable protein clients, many of which are key to a variety of signal transduction pathways. HSP90 function has been best investigated in animal and fungal systems, where inhibition of the chaperone has exceptionally diverse effects, ranging from reversing oncogenic transformation to preventing the acquisition of drug resistance. Inhibition of HSP90 in the model plant Arabidopsis thaliana uncovers novel morphologies dependent on normally cryptic genetic variation and increases stochastic variation inherent to developmental processes. The biochemical activity of HSP90 is strictly conserved between animals and plants. However, the substrates and pathways dependent on HSP90 in plants are poorly understood. Progress has been impeded by the necessity of reliance on light-sensitive HSP90 inhibitors due to redundancy in the A. thaliana HSP90 gene family. Here we present phenotypic and genome-wide expression analyses of A. thaliana with constitutively reduced HSP90 levels achieved by RNAi targeting. HSP90 reduction affects a variety of quantitative life-history traits, including flowering time and total seed set, increases morphological diversity, and decreases the developmental stability of repeated characters. Several morphologies are synergistically affected by HSP90 and growth temperature. Genome-wide expression analyses also suggest a central role for HSP90 in the genesis and maintenance of plastic responses. The expression results are substantiated by examination of the response of HSP90-reduced plants to attack by caterpillars of the generalist herbivore Trichoplusia ni. HSP90 reduction potentiates a more robust herbivore defense response. In sum, we propose that HSP90 exerts global effects on the environmental responsiveness of plants to many different stimuli. The comprehensive set of HSP90-reduced lines described here is a vital instrument to further examine

  14. Environmental and genetic interactions reveal FLOWERING LOCUS C as a modulator of the natural variation for the plasticity of flowering in Arabidopsis.

    Science.gov (United States)

    Méndez-Vigo, Belén; Savic, Marija; Ausín, Israel; Ramiro, Mercedes; Martín, Beatriz; Picó, F Xavier; Alonso-Blanco, Carlos

    2016-02-01

    The timing of flowering initiation depends strongly on the environment, a property termed as the plasticity of flowering. Such plasticity determines the adaptive potential of plants because it provides phenotypic buffer against environmental changes, and its natural variation contributes to evolutionary adaptation. We addressed the genetic mechanisms of the natural variation for this plasticity in Arabidopsis thaliana by analysing a population of recombinant inbred lines derived from Don-0 and Ler accessions collected from distinct climates. Quantitative trait locus (QTL) mapping in four environmental conditions differing in photoperiod, vernalization treatment and ambient temperature detected the folllowing: (i) FLOWERING LOCUS C (FLC) as a large effect QTL affecting flowering time differentially in all environments; (ii) numerous QTL displaying smaller effects specifically in some conditions; and (iii) significant genetic interactions between FLC and other loci. Hence, the variation for the plasticity of flowering is determined by a combination of environmentally sensitive and specific QTL, and epistasis. Analysis of FLC from Don identified a new and more active allele likely caused by a cis-regulatory deletion covering the non-coding RNA COLDAIR. Further characterization of four FLC natural alleles showed different environmental and genetic interactions. Thus, FLC appears as a major modulator of the natural variation for the plasticity of flowering to multiple environmental factors. PMID:26173848

  15. Arabidopsis thaliana glucuronosyltransferase in family GT14

    DEFF Research Database (Denmark)

    Dilokpimol, Adiphol; Geshi, Naomi

    2014-01-01

    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 At...

  16. Structure and organ specificity of an anionic peroxidase from Arabidopsis thaliana cell suspension culture

    DEFF Research Database (Denmark)

    Ostergaard, L; Abelskov, A K; Mattsson, O; Welinder, K G

    The predominant peroxidase (pI 3.5) (E.C. 1.11.1.7) of an Arabidopsis thaliana cell suspension culture was purified and partially sequenced. Oligonucleotides were designed and a specific probe was obtained. A cDNA clone was isolated from an Arabidopsis cell suspension cDNA library and completely ...

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

    OpenAIRE

    PiisilÀ, Maria; Keceli, Mehmet A; Brader, GÌnter; Jakobson, Liina; Jõesaar, Indrek; Sipari, Nina; Kollist, Hannes; Palva, E. T.; Kariola, Tarja

    2015-01-01

    Abstract Background 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. Results A reverse genetic screen for F-box protein ...

  18. Genome-wide analysis of mutations in mutant lineages selected following fast-neutron irradiation mutagenesis of Arabidopsis thaliana

    KAUST Repository

    Belfield, E.J.

    2012-04-12

    Ionizing radiation has long been known to induce heritable mutagenic change in DNA sequence. However, the genome-wide effect of radiation is not well understood. Here we report the molecular properties and frequency of mutations in phenotypically selected mutant lines isolated following exposure of the genetic model flowering plant Arabidopsis thaliana to fast neutrons (FNs). Previous studies suggested that FNs predominantly induce deletions longer than a kilobase in A. thaliana. However, we found a higher frequency of single base substitution than deletion mutations. While the overall frequency and molecular spectrum of fast-neutron (FN)-induced single base substitutions differed substantially from those of "background" mutations arising spontaneously in laboratory-grown plants, G:C>A:T transitions were favored in both. We found that FN-induced G:C>A:T transitions were concentrated at pyrimidine dinucleotide sites, suggesting that FNs promote the formation of mutational covalent linkages between adjacent pyrimidine residues. In addition, we found that FNs induced more single base than large deletions, and that these single base deletions were possibly caused by replication slippage. Our observations provide an initial picture of the genome-wide molecular profile of mutations induced in A. thaliana by FN irradiation and are particularly informative of the nature and extent of genome-wide mutation in lines selected on the basis of mutant phenotypes from FN-mutagenized A. thaliana populations.

  19. DELAYED FLOWERING, an Arabidopsis Gene That Acts in the Autonomous Flowering Promotion Pathway and Is Required for Normal Development

    Institute of Scientific and Technical Information of China (English)

    Ming-Jie Chen; Zheng Yuan; Hai Huang

    2006-01-01

    The control of flowering time in higher plants is one of the most important physiological processes and is critical for their reproductive success. To investigate the mechanisms controlling flowering time, we screened for Arabidopsis mutants with late-flowering phenotypes. One mutant, designated delayed flowering (dfr) in the Landsberg erecta (Ler) ecotype, was identified with delayed flowering time. Genetic analysis revealed that dfr is a single gene recessive nuclear mutant and the mutation was mapped to a locus tightly linked to UFO on chromosome 1. To our knowledge, no gene regulating flowering time has been reported yet in this region. The dfr mutant plant showed a delayed flowering time under the different growth conditions examined,including long- and short-day photoperiods and gibberellic acid GA3 treatments, suggesting that DFR is a gene involved in the autonomous flowering promotion pathway. The Arabidopsis gene FLOWERING LOCUS C (FLC) plays a central role in repressing flowering and its transcripts are undetectable in wild-type Ler.However, FLCexpression was upregulated in the dfrmutant, suggesting that DFR is a negative regulator of FLC. In addition, the dfr mutant plant displayed altered valve shapes of the silique and the number of trichomes and branches of each trichome were both reduced, indicating that the DRFgene is also required for normal plant development. Moreover, dfr leafy-5 (Ify-5) double mutant plants showed a much later flowering time than either dfr or Ify-5 single mutants, indicating that DFR and LFYact synergistically to promote flowering in Arabidopsis.

  20. The relationship between flowering time and growth responses to drought in the Arabidopsis Landsberg erecta x Antwerp-1 population

    Directory of Open Access Journals (Sweden)

    Inga eSchmalenbach

    2014-11-01

    Full Text Available Limited water availability is one of the most prominent abiotic constraints to plant survival and reproduction. Thus, plants have evolved different strategies to cope with water deficit, including modification of their growth and timing of developmental events such as flowering. In this work, we explore the link between flowering time and growth responses to moderate drought stress in Arabidopsis thaliana using natural variation for these traits found in the Landsberg erecta x Antwerp-1 recombinant inbred line population. We developed and phenotyped near isogenic lines containing different allelic combinations at three interacting quantitative trait loci (QTL affecting both flowering time and growth in response to water deficit. We used these lines to confirm additive and epistatic effects of the three QTL and observed a strong association between late flowering and reduced sensitivity to drought. Analyses of growth responses to drought over time revealed that late flowering plants were able to recover their growth in the second half of their vegetative development. In contrast, early flowering, a common drought escape strategy that ensures plant survival under severe water deficit, was associated with strongly impaired plant fitness. The results presented here indicate that late flowering may be advantageous under continuous mild water deficit as it allows stress acclimatization over time.

  1. In planta localisation patterns of MADS domain proteins during floral development in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Kaufmann Kerstin

    2009-01-01

    Full Text Available Abstract Background MADS domain transcription factors play important roles in various developmental processes in flowering plants. Members of this family play a prominent role in the transition to flowering and the specification of floral organ identity. Several studies reported mRNA expression patterns of the genes encoding these MADS domain proteins, however, these studies do not provide the necessary information on the temporal and spatial localisation of the proteins. We have made GREEN FLUORESCENT PROTEIN (GFP translational fusions with the four MADS domain proteins SEPALLATA3, AGAMOUS, FRUITFULL and APETALA1 from the model plant Arabidopsis thaliana and analysed the protein localisation patterns in living plant tissues by confocal laser scanning microscopy (CLSM. Results We unravelled the protein localisation patterns of the four MADS domain proteins at a cellular and subcellular level in inflorescence and floral meristems, during development of the early flower bud stages, and during further differentiation of the floral organs. The protein localisation patterns revealed a few deviations from known mRNA expression patterns, suggesting a non-cell autonomous action of these factors or alternative control mechanisms. In addition, we observed a change in the subcellular localisation of SEPALLATA3 from a predominantly nuclear localisation to a more cytoplasmic localisation, occurring specifically during petal and stamen development. Furthermore, we show that the down-regulation of the homeodomain transcription factor WUSCHEL in ovular tissues is preceded by the occurrence of both AGAMOUS and SEPALLATA3 proteins, supporting the hypothesis that both proteins together suppress WUSCHEL expression in the ovule. Conclusion This approach provides a highly detailed in situ map of MADS domain protein presence during early and later stages of floral development. The subcellular localisation of the transcription factors in the cytoplasm, as observed at

  2. MicroProtein-mediated recruitment of CONSTANS into a TOPLESS trimeric complex represses flowering in Arabidopsis

    DEFF Research Database (Denmark)

    Graeff, Moritz; Straub, Daniel; Eguen, Tenai E.;

    2016-01-01

    Arabidopsis thaliana microProteins, miP1a and miP1b, physically interact with CONSTANS (CO) a potent regulator of flowering time. The miP1a/b-type microProteins evolved in dicotyledonous plants and have an additional carboxy-terminal PF(V/L)FL motif. This motif enables miP1a/b microProteins to interact with...... TOPLESS/TOPLESS-RELATED (TPL/TPR) proteins. Interaction of CO with miP1a/b/TPL causes late flowering due to a failure in the induction of FLOWERING LOCUS T (FT) expression under inductive long day conditions. Both miP1a and miP1b are expressed in vascular tissue, where CO and FT are active. Genetically......MicroProteins are short, single domain proteins that act by sequestering larger, multi-domain proteins into non-functional complexes. MicroProteins have been identified in plants and animals, where they are mostly involved in the regulation of developmental processes. Here we show that two...

  3. 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

  4. Internet Resources for Gene Expression Analysis in Arabidopsis thaliana.

    Science.gov (United States)

    Hehl, Reinhard; Bülow, Lorenz

    2008-09-01

    The number of online databases and web-tools for gene expression analysis in Arabidopsis thaliana has increased tremendously during the last years. These resources permit the database-assisted identification of putative cis-regulatory DNA sequences, their binding proteins, and the determination of common cis-regulatory motifs in coregulated genes. DNA binding proteins may be predicted by the type of cis-regulatory motif. Further questions of combinatorial control based on the interaction of DNA binding proteins and the colocalization of cis-regulatory motifs can be addressed. The database-assisted spatial and temporal expression analysis of DNA binding proteins and their target genes may help to further refine experimental approaches. Signal transduction pathways upstream of regulated genes are not yet fully accessible in databases mainly because they need to be manually annotated. This review focuses on the use of the AthaMap and PathoPlant((R)) databases for gene expression regulation analysis and discusses similar and complementary online databases and web-tools. Online databases are helpful for the development of working hypothesis and for designing subsequent experiments. PMID:19506727

  5. Functional bias in molecular evolution rate of Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Anandakrishnan Ramu

    2010-05-01

    Full Text Available Abstract Background Characteristics derived from mutation and other mechanisms that are advantageous for survival are often preserved during evolution by natural selection. Some genes are conserved in many organisms because they are responsible for fundamental biological function, others are conserved for their unique functional characteristics. Therefore one would expect the rate of molecular evolution for individual genes to be dependent on their biological function. Whether this expectation holds for genes duplicated by whole genome duplication is not known. Results We empirically demonstrate here, using duplicated genes generated from the Arabidopsis thaliana α-duplication event, that the rate of molecular evolution of genes duplicated in this event depend on biological function. Using functional clustering based on gene ontology annotation of gene pairs, we show that some duplicated genes, such as defense response genes, are under weaker purifying selection or under stronger diversifying selection than other duplicated genes, such as protein translation genes, as measured by the ratio of nonsynonymous to synonymous divergence (dN/dS. Conclusions These results provide empirical evidence indicating that molecular evolution rate for genes duplicated in whole genome duplication, as measured by dN/dS, may depend on biological function, which we characterize using gene ontology annotation. Furthermore, the general approach used here provides a framework for comparative analysis of molecular evolution rate for genes based on their biological function.

  6. 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.

  7. 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. PMID:27419873

  8. Profiling of secondary metabolites in root exudates of Arabidopsis thaliana.

    Science.gov (United States)

    Strehmel, Nadine; Böttcher, Christoph; Schmidt, Stephan; Scheel, Dierk

    2014-12-01

    To explore the chemical composition of root exudates of the model plant Arabidopsis thaliana a workflow for nontargeted metabolite profiling of the semipolar fraction of root exudates was developed. It comprises hydroponic plant cultivation and sampling of root exudates under sterile conditions, sample preparation by solid-phase extraction and analysis by reversed-phase UPLC/ESI-QTOFMS. Following the established workflow, root exudates of six-week-old plants were profiled and a set of reproducibly occurring molecular features was compiled. To structurally elucidate the corresponding metabolites, accurate mass tandem mass spectrometry and on-line hydrogen/deuterium exchange were applied. Currently, a total of 103 compounds were detected and annotated by elemental composition of which more than 90 were structurally characterized or classified. Among them, 42 compounds were rigorously identified using an authenticated standard. The compounds identified so far include nucleosides, deoxynucleosides, aromatic amino acids, anabolites and catabolites of glucosinolates, dipeptides, indolics, salicylic and jasmonic acid catabolites, coumarins, mono-, di- and trilignols, hydroxycinnamic acid derivatives and oxylipins and exemplify the high chemical diversity of plant root exudates. PMID:25457500

  9. 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. PMID:17412735

  10. Lagging adaptation to warming climate in Arabidopsis thaliana.

    Science.gov (United States)

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

    2014-06-01

    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

  11. 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.

  12. Plastid DNA polymerases from higher plants, Arabidopsis thaliana

    International Nuclear Information System (INIS)

    Previously, we described a novel DNA polymerase, designated as OsPolI-like, from rice. The OsPolI-like showed a high degree of sequence homology with the DNA polymerase I of cyanobacteria and was localized in the plastid. Here, we describe two PolI-like polymerases, designated as AtPolI-like A and AtPolI-like B, from Arabidopsis thaliana. In situ hybridization analysis demonstrated expression of both mRNAs in proliferating tissues such as the shoot apical meristem. Analysis of the localizations of GFP fusion proteins showed that AtPolI-like A and AtPolI-like B were localized to plastids. AtPolI-like B expression could be induced by exposure to the mutagen H2O2. These results suggested that AtPolI-like B has a role in the repair of oxidation-induced DNA damage. Our data indicate that higher plants possess two plastid DNA polymerases that are not found in animals and yeasts

  13. Mutants of Arabidopsis thaliana hypersensitive to DNA-damaging treatments

    International Nuclear Information System (INIS)

    A simple screening method was developed for the isolation of Arabidopsis thaliana mutants hypersensitive to X-ray irradiation. The root meristem was used as the target for irradiation with sublethal doses of X rays, while protection of the shoot meristem by a lead cover allowed the rescue of hypersensitive individuals. We isolated nine independent X-ray-hypersensitive mutants from 7000 M2 seedlings. Analysis of three chosen mutants (xrs4, xrs9 and xrs11) showed that alterations in single recessive alleles are responsible for their phenotypes. The mutations are not allelic but linked and map to chromosome 4, suggesting mutations in novel genes as compared to previously mapped mutant alleles. Importantly, hypersensitivity to X rays was found to correlate with hypersensitivity to the DNA-alkylating agent mitomycin C, which provokes interstrand crosslinks, and/or to methyl methanesulfonate, which is known as a radiomimetic chemical. These novel phenotypes suggest that the mutants described here are altered in the repair of DNA damage, most probably by recombinational repair

  14. 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

  15. Drought Stress Predominantly Endures Arabidopsis thaliana to Pseudomonas syringae Infection

    Directory of Open Access Journals (Sweden)

    Aarti eGupta

    2016-06-01

    Full Text Available Plant responses to a combination of drought and bacterial pathogen infection, an agronomically important and altogether a new stress, are not well studied. While occurring concurrently, these two stresses can lead to synergistic or antagonistic effects on plants due to stress-interaction. It is reported that plant responses to the stress combinations consist of both strategies unique to combined stress and those shared between combined and individual stresses. However, the combined stress response mechanisms governing stress interaction and net impact are largely unknown. In order to study these adaptive strategies, an accurate and convenient methodology is lacking even in model plants like Arabidopsis thaliana. The gradual nature of drought stress imposition protocol poses a hindrance in simultaneously applying pathogen infection under laboratory conditions to achieve combined stress. In present study we aimed to establish systematic combined stress protocol and to study physiological responses of the plants to various degrees of combined stress. Here, we have comprehensively studied the impact of combined drought and Pseudomonas syringae pv. tomato DC3000 infection on A. thaliana. Further, by employing different permutations of drought and pathogen stress intensities, an attempt was made to dissect the contribution of each individual stress effects during their concurrence. We hereby present two main aspects of combined stress viz., stress interaction and net impact of the stress on plants. Mainly, this study establishes a systematic protocol to assess the impact of combined drought and bacterial pathogen stress. It was observed that as a result of net impact, some physiological responses under combined stress are tailored when compared to the plants exposed to individual stresses. We also infer that plant responses under combined stress in this study are predominantly influenced by the drought stress. Our results show that pathogen induced

  16. 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

    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......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....... RESULTS: In this study, we report genome-scale transcript response diversity of 10 A. thaliana ecotypes originating from different geographical locations to non-freezing cold stress (10°C). To analyze the transcriptional response diversity, we initially compared transcriptome changes in all 10 ecotypes...

  17. No detectable maternal effects of elevated CO(2 on Arabidopsis thaliana over 15 generations.

    Directory of Open Access Journals (Sweden)

    Nianjun Teng

    Full Text Available Maternal environment has been demonstrated to produce considerable impact on offspring growth. However, few studies have been carried out to investigate multi-generational maternal effects of elevated CO(2 on plant growth and development. Here we present the first report on the responses of plant reproductive, photosynthetic, and cellular characteristics to elevated CO(2 over 15 generations using Arabidopsis thaliana as a model system. We found that within an individual generation, elevated CO(2 significantly advanced plant flowering, increased photosynthetic rate, increased the size and number of starch grains per chloroplast, reduced stomatal density, stomatal conductance, and transpiration rate, and resulted in a higher reproductive mass. Elevated CO(2 did not significantly influence silique length and number of seeds per silique. Across 15 generations grown at elevated CO(2 concentrations, however, there were no significant differences in these traits. In addition, a reciprocal sowing experiment demonstrated that elevated CO(2 did not produce detectable maternal effects on the offspring after fifteen generations. Taken together, these results suggested that the maternal effects of elevated CO(2 failed to extend to the offspring due to the potential lack of genetic variation for CO(2 responsiveness, and future plants may not evolve specific adaptations to elevated CO(2 concentrations.

  18. Host responses in life-history traits and tolerance to virus infection in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Israel Pagán

    Full Text Available Knowing how hosts respond to parasite infection is paramount in understanding the effects of parasites on host populations and hence host-parasite co-evolution. Modification of life-history traits in response to parasitism has received less attention than other defence strategies. Life-history theory predicts that parasitised hosts will increase reproductive effort and accelerate reproduction. However, empirical analyses of these predictions are few and mostly limited to animal-parasite systems. We have analysed life-history trait responses in 18 accessions of Arabidopsis thaliana infected at two different developmental stages with three strains of Cucumber mosaic virus (CMV. Accessions were divided into two groups according to allometric relationships; these groups differed also in their tolerance to CMV infection. Life-history trait modification upon virus infection depended on the host genotype and the stage at infection. While all accessions delayed flowering, only the more tolerant allometric group modified resource allocation to increase the production of reproductive structures and progeny, and reduced the length of reproductive period. Our results are in agreement with modifications of life-history traits reported for parasitised animals and with predictions from life-history theory. Thus, we provide empirical support for the general validity of theoretical predictions. In addition, this experimental approach allowed us to quantitatively estimate the genetic determinism of life-history trait plasticity and to evaluate the role of life-history trait modification in defence against parasites, two largely unexplored issues.

  19. Somatic hybrids between Arabidopsis thaliana and cytoplasmic male-sterile radish (Raphanus sativus).

    Science.gov (United States)

    Yamagishi, H; Glimelius, K

    2003-08-01

    Somatic hybrids were produced by protoplast fusion between Arabidopsis thaliana ecotype Columbia and a male-sterile radish line MS-Gensuke ( Raphanus sativus) with the Ogura cytoplasm. Forty-one shoots were differentiated from the regenerated calli and established as shoot cultures in vitro. About 20 of these shoots were judged to be hybrids based on growth characteristics and morphology. Molecular analyses of 11 shoots were performed, confirming the hybrid features. Of these 11 shoots, eight were established as rooted plants in the greenhouse. Polymerase chain reaction and randomly amplified polymorphic DNA analyses of the nuclear genomes of all analyzed shoots and plants confirmed that they contained hybrid DNA patterns. Their chromosome numbers also supported the hybrid nature of the plants. Investigations of the organelles in the hybrids revealed that the chloroplast (cp) genome was exclusively represented by radish cpDNA, while the mitochondrial DNA configuration showed a combination of both parental genomes as well as fragments unique to the hybrids. Hybrid plants that flowered were male-sterile independent of the presence of the Ogura CMS-gene orf138. PMID:12827437

  20. The plant secondary metabolite citral alters water status and prevents seed formation in Arabidopsis thaliana.

    Science.gov (United States)

    Graña, E; Díaz-Tielas, C; López-González, D; Martínez-Peñalver, A; Reigosa, M J; Sánchez-Moreiras, A M

    2016-05-01

    Based on previous results, which showed that the secondary metabolite citral causes disturbances to plant water status, the present study is focused on demonstrating and detailing these effects on the water-related parameters of Arabidopsis thaliana adult plants, and their impact on plant fitness. Clear evidence of effects on water status and fitness were observed: plants treated with 1200 and 2400 μm citral showed decreased RWC, reduced Ψs , increased Ψw and reduced stomatal opening, even 7 days after the beginning of the experiment. Plant protection signals, such as leaf rolling or increased anthocyanin content, were also detected in these plants. In contrast, 14 days after beginning the treatment, treated plants showed signs of citral-related damage. Moreover, the reproductive success of treated plants was critically compromised, with prematurely withered flowers and no silique or seed development. This effect of citral on fitness of adult plants suggests a promising application of this natural compound in weed management by reducing the weed seed bank in the soil. PMID:26587965

  1. QTL mapping in new Arabidopsis thaliana advanced intercross-recombinant inbred lines.

    Directory of Open Access Journals (Sweden)

    Sureshkumar Balasubramanian

    Full Text Available BACKGROUND: Even when phenotypic differences are large between natural or domesticated strains, the underlying genetic basis is often complex, and causal genomic regions need to be identified by quantitative trait locus (QTL mapping. Unfortunately, QTL positions typically have large confidence intervals, which can, for example, lead to one QTL being masked by another, when two closely linked loci are detected as a single QTL. One strategy to increase the power of precisely localizing small effect QTL, is the use of an intercross approach before inbreeding to produce Advanced Intercross RILs (AI-RILs. METHODOLOGY/PRINCIPAL FINDINGS: We present two new AI-RIL populations of Arabidopsis thaliana genotyped with an average intermarker distance of 600 kb. The advanced intercrossing design led to expansion of the genetic map in the two populations, which contain recombination events corresponding to 50 kb/cM in an F(2 population. We used the AI-RILs to map QTL for light response and flowering time, and to identify segregation distortion in one of the AI-RIL populations due to a negative epistatic interaction between two genomic regions. CONCLUSIONS/SIGNIFICANCE: The two new AI-RIL populations, EstC and KendC, derived from crosses of Columbia (Col to Estland (Est-1 and Kendallville (Kend-L provide an excellent resource for high precision QTL mapping. Moreover, because they have been genotyped with over 100 common markers, they are also excellent material for comparative QTL mapping.

  2. Genetic Analysis of Gravity Signal Transduction in Arabidopsis thaliana Seedlings

    Science.gov (United States)

    Boonsirichai, K.; Harrison, B.; Stanga, J.; Young, L.-S.; Neal, C.; Sabat, G.; Murthy, N.; Harms, A.; Sedbrook, J.; Masson, P.

    The primary roots of Arabidopsis thaliana seedlings respond to gravity stimulation by developing a tip curvature that results from differential cellular elongation on opposite flanks of the elongation zone. This curvature appears modulated by a lateral gradient of auxin that originates in the gravity-perceiving cells (statocytes) of the root cap through an apparent lateral repositioning of a component the auxin efflux carrier complex within these cells (Friml et al, 2002, Nature 415: 806-809). Unfortunately, little is known about the molecular mechanisms that govern early phases of gravity perception and signal transduction within the root-cap statocytes. We have used a molecular genetic approach to uncover some of these mechanisms. Mutations in the Arabidopsis ARG1 and ARL2 genes, which encode J-domain proteins, resulted in specific alterations in root and hypocotyl gravitropism, without pleiotropic phenotypes. Interestingly, ARG1 and ARL2 appear to function in the same genetic pathway. A combination of molecular genetic, biochemical and cell-biological approaches were used to demonstrate that ARG1 functions in early phases of gravity signal transduction within the root and hypocotyl statocytes, and is needed for efficient lateral auxin transport within the cap. The ARG1 protein is associated with components of the secretory and/or endosomal pathways, suggesting its role in the recycling of components of the auxin efflux carrier complex between plasma membrane and endosome (Boonsirichai et al, 2003, Plant Cell 15:2612-2625). Genetic modifiers of arg1-2 were isolated and shown to enhance the gravitropic defect of arg1-2, while resulting in little or no gravitropic defects in a wild type ARG1 background. A slight tendency for arg1-2;mar1-1 and arg1-2;mar2-1 double-mutant organs to display an opposite gravitropic response compared to wild type suggests that all three genes contribute to the interpretation of the gravity-vector information by seedling organs. The

  3. Structural diversity and transcription of class III peroxidases from Arabidopsis thaliana.

    Science.gov (United States)

    Welinder, Karen G; Justesen, Annemarie F; Kjaersgård, Inger V H; Jensen, Rikke B; Rasmussen, Søren K; Jespersen, Hans M; Duroux, Laurent

    2002-12-01

    Understanding peroxidase function in plants is complicated by the lack of substrate specificity, the high number of genes, their diversity in structure and our limited knowledge of peroxidase gene transcription and translation. In the present study we sequenced expressed sequence tags (ESTs) encoding novel heme-containing class III peroxidases from Arabidopsis thaliana and annotated 73 full-length genes identified in the genome. In total, transcripts of 58 of these genes have now been observed. The expression of individual peroxidase genes was assessed in organ-specific EST libraries and compared to the expression of 33 peroxidase genes which we analyzed in whole plants 3, 6, 15, 35 and 59 days after sowing. Expression was assessed in root, rosette leaf, stem, cauline leaf, flower bud and cell culture tissues using the gene-specific and highly sensitive reverse transcriptase-polymerase chain reaction (RT-PCR). We predicted that 71 genes could yield stable proteins folded similarly to horseradish peroxidase (HRP). The putative mature peroxidases derived from these genes showed 28-94% amino acid sequence identity and were all targeted to the endoplasmic reticulum by N-terminal signal peptides. In 20 peroxidases these signal peptides were followed by various N-terminal extensions of unknown function which are not present in HRP. Ten peroxidases showed a C-terminal extension indicating vacuolar targeting. We found that the majority of peroxidase genes were expressed in root. In total, class III peroxidases accounted for an impressive 2.2% of root ESTs. Rather few peroxidases showed organ specificity. Most importantly, genes expressed constitutively in all organs and genes with a preference for root represented structurally diverse peroxidases (< 70% sequence identity). Furthermore, genes appearing in tandem showed distinct expression profiles. The alignment of 73 Arabidopsis peroxidase sequences provides an easy access to the identification of orthologous peroxidases

  4. DNA Gyrase Is the Target for the Quinolone Drug Ciprofloxacin in Arabidopsis thaliana *

    OpenAIRE

    Evans-Roberts, Katherine M.; Mitchenall, Lesley A.; Wall, Melisa K.; Leroux, Julie; Mylne, Joshua S; Maxwell, Anthony

    2015-01-01

    The Arabidopsis thaliana genome contains four genes that were originally annotated as potentially encoding DNA gyrase: ATGYRA, ATGYRB1, ATGYRB2, and ATGYRB3. Although we subsequently showed that ATGYRB3 does not encode a gyrase subunit, the other three genes potentially encode subunits of a plant gyrase. We also showed evidence for the existence of supercoiling activity in A. thaliana and that the plant is sensitive to quinolone and aminocoumarin antibiotics, compounds that target DNA gyrase ...

  5. Microscopic Evaluation of Interactions between Varieties of Arabidopsis thaliana Challenged by Peronospora parasitica

    OpenAIRE

    TÜRK*, Figen MERT

    2002-01-01

    Peronospora parasitica (Pers ex Fr.) Pers. is an obligate biotrophic pathogen that causes downy mildew in Arabidopsis thaliana (L.) Heynh. In this study, cotyledons of four A. thaliana varieties were inoculated with the Cala2 isolate of P. parasitica and the degree of susceptibility was observed under the microscope 1, 2, 3 and 7 days after inoculation (DAI). Microscopic examination of infected tissues revealed that early restriction of the pathogen was accompanied by a hypersensitive respons...

  6. Primary stress responses in Arabidopsis thaliana exposed to gamma radiation

    International Nuclear Information System (INIS)

    As the environment is inevitably exposed to ionizing radiation from natural and anthropogenic sources, it is important to evaluate gamma radiation induced stress responses in plants. The objective of this research is therefore to investigate radiation effects in Arabidopsis thaliana on individual and subcellular level by exposing 2-weeks-old seedlings for 7 days to total doses of 3.9 Gy, 6.7 Gy, 14.8 Gy and 58.8 Gy and evaluating growth, photosynthesis, chlorophyll a, chlorophyll b and carotenoid concentrations and antioxidative enzyme capacities. While the capacity of photosystem II (PSII measured as Fv/Fm) remained intact, plants started optimizing their photosynthetic process at the lower radiation doses by increasing the PSII efficiency (φPSII) and the maximal electron transport rate (ETRmax) and by decreasing the non-photochemical quenching (NPQ). At the highest radiation dose, photosynthetic parameters resembled those of control conditions. On subcellular level, roots showed increased superoxide dismutase (SOD) and ascorbate peroxidase (APX) capacities under gamma irradiation but catalase (CAT), syringaldazine peroxidase (SPX) and guaiacol peroxidase (GPX) activities, on the other hand, decreased. In the leaves no alterations were observed in SOD, CAT and SPX capacities, but GPX was highly affected. Based on these results it seems that roots are more sensitive for oxidative stress under gamma radiation exposure than leaves. - Highlights: • The efficiency of photosystem II increased after irradiation with 3.9 to 14.8 Gy. • Also the maximal electron transport rate increased under these radiation conditions. • Non-photochemical quenching declined in leaves irradiated with 3.9, 6.7 and 14.8 Gy. • Photosynthetic parameters returned to control values in leaves exposed to 58.8 Gy. • Antioxidative enzyme capacities are mostly affected in irradiated roots

  7. 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.

  8. 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.

  9. Recent advances in biological effect and molecular mechanism of arabidopsis thaliana irradiated by ion beams

    International Nuclear Information System (INIS)

    Newly research progresses were summarized in effect of ion beams on seed surface, biological effect, growth, development, gravitropism and so on. Furthermore, mutation molecular mechanism of Arabidopsis thaliana was discussed, for example, alteration of DNA bases, DNA damage, chromosomal recombination, characteristics of mutant transmissibility, etc. Meanwhile, the achievements of transfer- ring extraneous gene to Arabidopsis thaliana by ion beams were reviewed in the paper. At last, the future prospective are also discussed here in mutation molecular mechanism and the potential application of biological effect of heavy ion beams. (authors)

  10. GORDITA, a young paralog of Arabidopsis thaliana Bsister MADS-box gene ABS, has undergone neofunctionalization

    OpenAIRE

    Erdmann, Robert

    2010-01-01

    Bsister genes, a clade with close relationships to the class B floral homeotic genes, have been conserved for more than 300 million years. Bsister genes in Arabidopsis thaliana underwent gene duplication probably before the diversification of Brassicaceae leading to the paralogue genes ARABIDOPSIS BSISTER (ABS) and GORDITA (GOA). The phenotype of the abs mutant, however, is rather mild as it shows only reduced seed coloration and defects in endothelium development. This thesis focuses on the ...

  11. ML3: a novel regulator of herbivory-induced responses in Arabidopsis thaliana

    OpenAIRE

    Fridborg, I.; Johansson, A; Lagensjo, J.; Leelarasamee, N.; Floková, K. (Kristýna); Tarkowská, D. (Danuše); Meijer, J.; Bejai, S.

    2013-01-01

    ML (MD2-related lipid recognition) proteins are known to enhance innate immune responses in mammals. This study reports the analysis of the putative ML gene family in Arabidopsis thaliana and suggests a role for the ML3 gene in herbivory-associated responses in plants. Feeding by larvae of the Lepidopteran generalist herbivore Spodoptera littoralis and larvae of the specialist herbivore Plutella xylostella activated ML3 transcription in leaf tissues. ML3 loss-of-function Arabidopsis plants we...

  12. Protein Interaction Network of Arabidopsis thaliana Female Gametophyte Development Identifies Novel Proteins and Relations

    OpenAIRE

    Hosseinpour, Batool; HajiHoseini, Vahid; Kashfi, Rafieh; Ebrahimie, Esmaeil; Hemmatzadeh, Farhid

    2012-01-01

    Although the female gametophyte in angiosperms consists of just seven cells, it has a complex biological network. In this study, female gametophyte microarray data from Arabidopsis thaliana were integrated into the Arabidopsis interactome database to generate a putative interaction map of the female gametophyte development including proteome map based on biological processes and molecular functions of proteins. Biological and functional groups as well as topological characteristics of the net...

  13. Use of Arabidopsis thaliana and Pseudomonas syringae in the Study of Plant Disease Resistance and Tolerance

    OpenAIRE

    Bent, Andrew F.; Kunkel, Barbara N.; Innes, Roger W.; Staskawicz, Brian J.

    1993-01-01

    The interaction between Arabidopsis thaliana and the bacterium Pseudomonas syringae is being developed as a model experimental system for plant pathology research. Race-specific ("gene-for-gene") resistance has been demonstrated for this interaction, and pathogen genes that determine avirulence have been isolated and characterized. Because certain lines of both Arabidopsis and soybean are resistant to bacteria carrying the avirulence genes avrRpt2 and avrB, extremely similar pathogen recognit...

  14. The control of starch degradation in Arabidopsis thaliana leaves at night

    OpenAIRE

    Feike, Doreen

    2013-01-01

    The aim of this work was to understand how Arabidopsis thaliana plants control starch degradation at night. Starch is the major energy reserve in Arabidopsis. It is broken down at night to maintain growth and metabolism of the plant, when photosynthesis is not possible. The rate of starch degradation follows a linear pattern and is matched to the length of the night period such that almost all starch is exhausted by dawn. The mechanisms and the proteins involved in controlling ...

  15. Inferring the Brassica rapa Interactome Using Protein-Protein Interaction Data from Arabidopsis thaliana.

    Science.gov (United States)

    Yang, Jianhua; Osman, Kim; Iqbal, Mudassar; Stekel, Dov J; Luo, Zewei; Armstrong, Susan J; Franklin, F Chris H

    2012-01-01

    Following successful completion of the Brassica rapa sequencing project, the next step is to investigate functions of individual genes/proteins. For Arabidopsis thaliana, large amounts of protein-protein interaction (PPI) data are available from the major PPI databases (DBs). It is known that Brassica crop species are closely related to A. thaliana. This provides an opportunity to infer the B. rapa interactome using PPI data available from A. thaliana. In this paper, we present an inferred B. rapa interactome that is based on the A. thaliana PPI data from two resources: (i) A. thaliana PPI data from three major DBs, BioGRID, IntAct, and TAIR. (ii) ortholog-based A. thaliana PPI predictions. Linking between B. rapa and A. thaliana was accomplished in three complementary ways: (i) ortholog predictions, (ii) identification of gene duplication based on synteny and collinearity, and (iii) BLAST sequence similarity search. A complementary approach was also applied, which used known/predicted domain-domain interaction data. Specifically, since the two species are closely related, we used PPI data from A. thaliana to predict interacting domains that might be conserved between the two species. The predicted interactome was investigated for the component that contains known A. thaliana meiotic proteins to demonstrate its usability. PMID:23293649

  16. Inferring the Brassica rapa interactome using protein-protein interaction data from Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Jianhua eYang

    2013-01-01

    Full Text Available Following successful completion of the Brassica rapa sequencing project, the next step is to investigate functions of individual genes/proteins. For Arabidopsis thaliana, large amounts of protein-protein interaction (PPI data are available from the major PPI databases. It is known that Brassica crop species are closely related to A. thaliana. This provides an opportunity to infer the B. rapa interactome using PPI data available from A. thaliana. In this paper, we present an inferred B. rapa interactome that is based on the A. thaliana PPI data from two resources: (i A. thaliana PPI data from three major databases, BioGRID, IntAct and TAIR. (ii ortholog-based A. thaliana PPI predictions. Linking between B. rapa and A. thaliana was accomplished in three complementary ways: (i ortholog predictions, (ii identification of gene duplication based on synteny and collinearity, and (iii BLAST sequence similarity search. A complementary approach was also applied, which used known/predicted domain-domain interaction data. Specifically, since the two species are closely related, we used PPI data from A. thaliana to predict interacting domains that might be conserved between the two species. The predicted interactome was investigated for the component that contains known A. thaliana meiotic proteins to demonstrate its usability.

  17. The ABC transporter BcatrB from Botrytis cinerea exports camalexin and is a virulence factor on Arabidopsis thaliana

    OpenAIRE

    Stefanato, Francesca L.; Abou-Mansour, Eliane; Buchala, Antony; Kretschmer, Matthias; Mosbach, Andreas; Hahn, Matthias; Bochet, Christian G.; Métraux, Jean-Pierre; Schoonbeek, Henk-jan

    2009-01-01

    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 mut...

  18. A gene family derived from transposable elements during early angiosperm evolution has reproductive fitness benefits in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Zoé Joly-Lopez

    2012-09-01

    Full Text Available The benefits of ever-growing numbers of sequenced eukaryotic genomes will not be fully realized until we learn to decipher vast stretches of noncoding DNA, largely composed of transposable elements. Transposable elements persist through self-replication, but some genes once encoded by transposable elements have, through a process called molecular domestication, evolved new functions that increase fitness. Although they have conferred numerous adaptations, the number of such domesticated transposable element genes remains unknown, so their evolutionary and functional impact cannot be fully assessed. Systematic searches that exploit genomic signatures of natural selection have been employed to identify potential domesticated genes, but their predictions have yet to be experimentally verified. To this end, we investigated a family of domesticated genes called MUSTANG (MUG, identified in a previous bioinformatic search of plant genomes. We show that MUG genes are functional. Mutants of Arabidopsis thaliana MUG genes yield phenotypes with severely reduced plant fitness through decreased plant size, delayed flowering, abnormal development of floral organs, and markedly reduced fertility. MUG genes are present in all flowering plants, but not in any non-flowering plant lineages, such as gymnosperms, suggesting that the molecular domestication of MUG may have been an integral part of early angiosperm evolution. This study shows that systematic searches can be successful at identifying functional genetic elements in noncoding regions and demonstrates how to combine systematic searches with reverse genetics in a fruitful way to decipher eukaryotic genomes.

  19. Conservation and diversification of QTGs involved in photoperiodic flowering between rice and Arabidopsis

    Directory of Open Access Journals (Sweden)

    Kazuki eMatsubara

    2014-05-01

    Full Text Available Flowering time in rice (Oryza sativa L. is determined primarily by daylength (photoperiod, and natural variation in flowering time is due to quantitative trait loci involved in photoperiodic flowering. To date, genetic analysis of natural variants in rice flowering time has resulted in the positional cloning of at least 12 quantitative trait genes (QTGs, including our recently cloned QTGs, Hd17 and Hd16. The QTGs have been assigned to specific photoperiodic flowering pathways. Among them, 9 have homologs in the Arabidopsis genome, whereas it was evident that there are differences in the pathways between rice and Arabidopsis, such that the rice Ghd7–Ehd1–Hd3a/RFT1 pathway modulated by Hd16 is not present in Arabidopsis. In this review, we describe QTGs underlying natural variation in rice flowering time. Additionally, we discuss the implications of the variation in adaptive divergence and its importance in rice breeding.

  20. Radiosensitivity of Arabidopsis thaliana L. in condition of influence of low ionizing radiation doses

    International Nuclear Information System (INIS)

    Arabidopsis thaliana is a convenient genetic object. This work represents the date of laboratory experiments concerning research of influence of chronic γ-irradiation on plants of arabidopsis at rosette stage (short stemmed mutant Lansberg Erecta). The findings contribute to the high sensitivity of rosette stage of arabidopsis to irradiation by γ-rays in low doses (0.67-10.0 cGy). It is shown in depressing effects of ionising radiation on growth, development, vitality and bearing of plants, but also in hightened output morphological anomalies of plants and embryonic lethalities in pods. (authors)

  1. Impact of elevated CO2 on growth and development of Arabidopsis thaliana L

    NARCIS (Netherlands)

    van der Kooij, T.A W; De Kok, L.J.

    1996-01-01

    After germination, Arabidopsis thaliana L (cv. Landsberg) was grown at 350 mu l l(-1) (control) or 700 mu l l(-1) (elevated) CO2. Total shoot biomass at the end of the vegetative growth period was increased by 56% due to a short transient stimulation of the relative growth rate by elevated CO2 at th

  2. Differentially expressed genes associated with dormancy or germination of Arabidopsis thaliana seeds

    NARCIS (Netherlands)

    Toorop, P.E.; Barroco, R.M.; Engler, G.; Groot, S.P.C.; Hilhorst, H.W.M.

    2005-01-01

    Differential display analysis using dormant and non-dormant Arabidopsis thaliana (L.) Heynh seeds resulted in a set of genes that were associated with either dormancy or germination. Expression of the germination-associated genes AtRPL36B and AtRPL27B, encoding two ribosomal proteins, was undetectab

  3. 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 (JA...... common to class V chitinases from higher plants....

  4. Supermolecular organization of photosystem II and its associated light-harvesting antenna in Arabidopsis thaliana

    NARCIS (Netherlands)

    Yakushevska, AE; Jensen, PE; Keegstra, W; van Roon, H; Scheller, HV; Boekema, EJ; Dekker, JP; Yakushevska, Alevtyna E.; Jensen, Poul E.; Scheller, Henrik V.; Dekker, Jan P.

    2001-01-01

    The organization of Arabidopsis thaliana photosystem II (PSII) and its associated light-harvesting antenna (LHCII) was studied in isolated PSII-LHCII supercomplexes and native membrane-bound crystals by transmission electron microscopy and image analysis. Over 4000 single-particle projections of PSI

  5. The role of ATM in maintenance of telomeres in Arabidopsis thaliana

    Czech Academy of Sciences Publication Activity Database

    Široký, Jiří; Mokroš, Petr; Vespa, L.; Shippen, D.

    Southampton, 2006. C2.37-C2.37. [Cell Cycle Symposium. 03.07.2006-06.07.2006, Southampton] R&D Projects: GA ČR(CZ) GA522/06/0380 Institutional research plan: CEZ:AV0Z50040507 Keywords : Arabidopsis thaliana * DNA repair * ataxia telangiectasia mutated Subject RIV: BO - Biophysics

  6. Effects of Preconditioning and Temperature During Germination of 73 Natural Accessions of Arabidopsis thaliana

    OpenAIRE

    Schmuths, Heike; BACHMANN, KONRAD; WEBER, W. EBERHARD; Horres, Ralf; Matthias H Hoffmann

    2006-01-01

    • Background and Aims Germination and establishment of seeds are complex traits affected by a wide range of internal and external influences. The effects of parental temperature preconditioning and temperature during germination on germination and establishment of Arabidopsis thaliana were examined.

  7. Temperature as a determinant factor for increased and reproducible in vitro pollen germination in Arabidopsis thaliana

    Science.gov (United States)

    Despite much effort, a robust protocol for in vitro germination of Arabidopsis thaliana pollen was still elusive. Here we show that controlled temperatures, a largely disregarded factor in previous studies, and a simple optimized medium, solidified or liquid, yielded pollen germination rates above 8...

  8. Whole-Genome Shotgun Sequence of Pseudomonas viridiflava, a Bacterium Species Pathogenic to Arabidopsis thaliana

    OpenAIRE

    Lefort, Francois; Calmin, Gautier; Crovadore, Julien; Osteras, Magne; Farinelli, Laurent

    2013-01-01

    We report here the first whole-genome shotgun sequence of Pseudomonas viridiflava strain UASWS38, a bacterium species pathogenic to the biological model plant Arabidopsis thaliana but also usable as a biological control agent and thus of great scientific interest for understanding the genetics of plant-microbe interactions.

  9. 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

  10. An En/Spm based transposable element system for gene isolation in Arabidopsis thaliana.

    NARCIS (Netherlands)

    Aarts, M.G.M.

    1996-01-01

    At the start of the research described in this thesis, the main aim was to develop, study and apply an efficient En/Spm-I/dSpm based transposon tagging system in Arabidopsis thaliana to generate tagged mutants and to provide insights in the possibilities for future applications of such a transposon

  11. A composite transcriptional signature differentiates responses towards closely related herbicides in Arabidopsis thaliana and brassica napus

    Science.gov (United States)

    In this study, genome-wide expression profiling based on Affymetrix ATH1 arrays was used to identify discriminating responses of Arabidopsis thaliana to five herbicides, which contain active ingredients targeting two different branches of amino acid biosynthesis. One herbicide co...

  12. In vivo optical detection of pH in microscopic tissue samples of Arabidopsis thaliana

    Czech Academy of Sciences Publication Activity Database

    Kašík, Ivan; Podrazký, Ondřej; Mrázek, Jan; Martan, Tomáš; Matějec, Vlastimil; Hoyerová, Klára; Kamínek, Miroslav

    2013-01-01

    Roč. 33, č. 8 (2013), s. 4809-4815. ISSN 0928-4931 R&D Projects: GA ČR GAP102/10/2139 Institutional support: RVO:67985882 ; RVO:61389030 Keywords : Ratiometric fluorescence * Arabidopsis thaliana * Tissue Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 2.736, year: 2013

  13. Konukçu-Patojen İlişkisinde Model Bir Bitki: Arabidopsis thaliana / A Model Plant In Host-Pathogen Interactıon: Arabidopsis thaliana

    OpenAIRE

    Mert Türk, Figen

    2011-01-01

    Özet. Arabidopsis thaliana (Arabidopsis)’nın kromozom sayısının az olması, bu bitkinin genetik yapısının diğer bitki türlerine göre daha kolay çalışılmasına olanak sağlamakta, ayrıca diğer bitkilerde patojenlere karşı gözlenen ana savunma mekanizmaları bu bitkide de bulunmaktadır. Bu açıdan, konukçu bitkilerin patojen saldırılarına karşı savunma mekanizmalarını çalışma konusunda Arabidopsis bitkisi ideal bir model sistem oluşturmaktadır. B...

  14. BRR2a Affects Flowering Time via FLC Splicing

    OpenAIRE

    Mahrez, Walid; Shin, Juhyun; Muñoz-Viana, Rafael; Figueiredo, Duarte D.; Trejo-Arellano, Minerva S.; Exner, Vivien; Siretskiy, Alexey; Gruissem, Wilhelm; Köhler, Claudia; Hennig, Lars

    2016-01-01

    Several pathways control time to flowering in Arabidopsis thaliana through transcriptional and posttranscriptional gene regulation. In recent years, mRNA processing has gained interest as a critical regulator of flowering time control in plants. However, the molecular mechanisms linking RNA splicing to flowering time are not well understood. In a screen for Arabidopsis early flowering mutants we identified an allele of BRR2a. BRR2 proteins are components of the spliceosome and highly conserve...

  15. Switching on flowers: transient LEAFY induction reveals novel aspects of the regulation of reproductive development in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Doris eWagner

    2011-10-01

    Full Text Available Developmental fate decisions in cell populations fundamentally depend on at least two parameters: a signal that is perceived by the cell and the intrinsic ability of the cell to respond to the signal. The same regulatory logic holds for phase transitions in the lifecycle of an organism, for example the switch to reproductive development in flowering plants. Here we have tested the response of the monocarpic plant species Arabidopsis thaliana to a signal that directs flower formation, the plant specific transcription factor LEAFY (LFY. Using transient steroid-dependent LEAFY (LFY activation in lfy null mutant Arabidopsis plants, we show that the plant’s competence to respond to the LFY signal changes during development. Very early in the life cycle, the plant is not competent to respond to the signal. Subsequently, transient LFY activation can direct primordia at the flanks of the shoot apical meristem to adopt a floral fate. Finally, the plants acquire competence to initiate the flower-patterning program in response to transient LFY activation. Similar to a perennial life strategy, we did not observe reprogramming of all primordia after perception of the transient signal, instead only a small number of meristems responded, followed by reversion to the prior developmental program. The ability to initiate flower formation and to direct flower patterning in response to transient LFY upregulation was dependent on the known direct LFY target APETALA1 (AP1. Prolonged LFY or activation could alter the developmental gradient and bypass the requirement for AP1. Prolonged high AP1 levels, in turn, can also alter the plants’ competence. Our findings shed light on how plants can fine-tune important phase transitions and developmental responses.

  16. Transcriptomic characterization of a synergistic genetic interaction during carpel margin meristem development in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    April N Wynn

    Full Text Available In flowering plants the gynoecium is the female reproductive structure. In Arabidopsis thaliana ovules initiate within the developing gynoecium from meristematic tissue located along the margins of the floral carpels. When fertilized the ovules will develop into seeds. SEUSS (SEU and AINTEGUMENTA (ANT encode transcriptional regulators that are critical for the proper formation of ovules from the carpel margin meristem (CMM. The synergistic loss of ovule initiation observed in the seu ant double mutant suggests that SEU and ANT share overlapping functions during CMM development. However the molecular mechanism underlying this synergistic interaction is unknown. Using the ATH1 transcriptomics platform we identified transcripts that were differentially expressed in seu ant double mutant relative to wild type and single mutant gynoecia. In particular we sought to identify transcripts whose expression was dependent on the coordinated activities of the SEU and ANT gene products. Our analysis identifies a diverse set of transcripts that display altered expression in the seu ant double mutant tissues. The analysis of overrepresented Gene Ontology classifications suggests a preponderance of transcriptional regulators including multiple members of the REPRODUCTIVE MERISTEMS (REM and GROWTH-REGULATING FACTOR (GRF families are mis-regulated in the seu ant gynoecia. Our in situ hybridization analyses indicate that many of these genes are preferentially expressed within the developing CMM. This study is the first step toward a detailed description of the transcriptional regulatory hierarchies that control the development of the CMM and ovule initiation. Understanding the regulatory hierarchy controlled by SEU and ANT will clarify the molecular mechanism of the functional redundancy of these two genes and illuminate the developmental and molecular events required for CMM development and ovule initiation.

  17. Carbon-14 labelled sucrose transportation in an Arabidopsis thaliana using an imaging plate and real time imaging system

    International Nuclear Information System (INIS)

    As an approach to increased production of rape seed oil from Brassica napus L., Arabidopsis thaliana, a species from the same Brassicaceae family, was used to investigate transport behavior and distribution of matter in the plant body. In this study, sucrose, an initial metabolic product of photosynthesis, labeled with carbon-14 was used. The sucrose was applied to A. thaliana via the surface of a rosette leaf. Using the real time radioisotope imaging system we developed and an imaging plate (IP), images of whole or part of the sample were obtained. The sucrose assimilation products were accumulated in maturing tissue such as flowers and fruits, and in a joint part. From the comparison among branches and stems, it was indicated that there were different patterns of demand and distribution of sucrose assimilation products depending on the tissue and its growing stage. This might be caused by either morphological reason such as diameter and location of the sieve tube, or genetic factors such as an activity of a membrane transport protein. Because of self-absorption of carpels, it was difficult to observe the accumulation of carbon-14 in the seeds inside the fruits; however, an IP image of a frozen section of a fruit revealed that carbon-14 transport to seeds was higher than that of carpels. These methods will help us gain insight into matter transport and strategies to improve the production of rape seed oil. (author)

  18. Arabidopsis thaliana gonidialess A/Zuotin related factors (GlsA/ZRF) are essential for maintenance of meristem integrity.

    Science.gov (United States)

    Guzmán-López, José Alfredo; Abraham-Juárez, María Jazmín; Lozano-Sotomayor, Paulina; de Folter, Stefan; Simpson, June

    2016-05-01

    Observation of a differential expression pattern, including strong expression in meristematic tissue of an Agave tequilana GlsA/ZRF ortholog suggested an important role for this gene during bulbil formation and developmental changes in this species. In order to better understand this role, the two GlsA/ZFR orthologs present in the genome of Arabidopsis thaliana were functionally characterized by analyzing expression patterns, double mutant phenotypes, promoter-GUS fusions and expression of hormone related or meristem marker genes. Patterns of expression for A. thaliana show that GlsA/ZFR genes are strongly expressed in SAMs and RAMs in mature plants and developing embryos and double mutants showed multiple changes in morphology related to both SAM and RAM tissues. Typical double mutants showed stunted growth of aerial and root tissue, formation of multiple ectopic meristems and effects on cotyledons, leaves and flowers. The KNOX genes STM and BP were overexpressed in double mutants whereas CLV3, WUSCHEL and AS1 were repressed and lack of AtGlsA expression was also associated with changes in localization of auxin and cytokinin. These results suggest that GlsA/ZFR is an essential component of the machinery that maintains the integrity of SAM and RAM tissue and underline the potential to identify new genes or gene functions based on observations in non-model plants. PMID:26826012

  19. The Structure, Distribution and Evolution of the Ta1 Retrotransposable Element Family of Arabidopsis Thaliana

    OpenAIRE

    Voytas, D. F.; Konieczny, A; Cummings, M. P.; Ausubel, F M

    1990-01-01

    The Ta1 elements are a low copy number, copia-like retrotransposable element family of Arabidopsis thaliana. Six Ta1 insertions comprise all of the Ta1 element copies found in three geographically diverse A. thaliana races. These six elements occupy three distinct target sites: Ta1-1 is located on chromosome 5 and is common to all three races (Col-0, Kas-1 and La-0). Ta1-2 is present in two races on chromosome 4 (Kas-1 and La-0), and Ta1-3, also located on chromosome 4, is present only in one...

  20. EMF1, a novel protein involved in the control of shoot architecture and flowering in Arabidopsis

    DEFF Research Database (Denmark)

    Aubert, D.; Chen, L.; Moon, Y.-H.;

    2001-01-01

    EMF1 shares common motifs that include nuclear localization signals, P-loop, and LXXLL elements. Alteration of EMF1 expression in transgenic plants caused progressive changes in flowering time, shoot determinacy, and inflorescence architecture. EMF1 and its related sequence may belong to a new class......Shoot architecture and flowering time in angiosperms depend on the balanced expression of a large number of flowering time and flower meristem identity genes. Loss-of-function mutations in the Arabidopsis EMBRYONIC FLOWER (EMF) genes cause Arabidopsis to eliminate rosette shoot growth and transform...... the apical meristem from indeterminate to determinate growth by producing a single terminal flower on all nodes. We have identified the EMF1 gene by positional cloning. The deduced polypeptide has no homology with any protein of known function except a putative protein in the rice genome with which...

  1. Arabidopsis FLOWERING LOCUS D influences systemic-acquiredresistance-induced expression and histone modifications of WRKY genes

    Indian Academy of Sciences (India)

    Vijayata Singh; Shweta Roy; Deepjyoti Singh; Ashis Kumar Nandi

    2014-03-01

    A plant that is in part infected by a pathogen is more resistant throughout its whole body to subsequent infections – a phenomenon known as systemic acquired resistance (SAR). Mobile signals are synthesized at the site of infection and distributed throughout the plant through vascular tissues. Mechanism of SAR development subsequent to reaching the mobile signal in the distal tissue is largely unknown. Recently we showed that FLOWERING LOCUS D (FLD) gene of Arabidopsis thaliana is required in the distal tissue to activate SAR. FLD codes for a homologue of human-lysine-specific histone demethylase. Here we show that FLD function is required for priming (SAR induced elevated expression during challenge inoculation) of WRKY29 and WRKY6 genes. FLD also differentially influences basal and SAR-induced expression of WRKY38, WRKY65 and WRKY53 genes. In addition, we also show that FLD partly localizes in nucleus and influences histone modifications at the promoters of WRKY29 and WRKY6 genes. The results altogether indicate to the possibility of FLD’s involvement in epigenetic regulation of SAR.

  2. Yeast Cell Wall Extract Induces Disease Resistance against Bacterial and Fungal Pathogens in Arabidopsis thaliana and Brassica Crop

    OpenAIRE

    Narusaka, Mari; Minami, Taichi; Iwabuchi, Chikako; Hamasaki, Takashi; Takasaki, Satoko; Kawamura, Kimito; Narusaka, Yoshihiro

    2015-01-01

    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 incre...

  3. Photoperiodic Regulation of Florigen Function in Arabidopsis thaliana

    Science.gov (United States)

    Golembeski, Greg S.; Imaizumi, Takato

    2015-01-01

    One mechanism through which flowering in response to seasonal change is brought about is by sensing the fluctuation in day-length; the photoperiod. Flowering induction occurs through the production of the florigenic protein FLOWERING LOCUS T (FT) and its movement from the phloem companion cells in the leaf vasculature into the shoot apex, where meristematic reprogramming occurs. FT activation in response to photoperiod condition is accomplished largely through the activity of the transcription factor CONSTANS (CO). Regulation of CO expression and protein stability, as well as the timing of other components via the circadian clock, is a critical mechanism by which plants are able to respond to photoperiod to initiate the floral transition. Modulation of FT expression in response to external and internal stimuli via components of the flowering network is crucial to mediate a fluid flowering response to a variety of environmental parameters. In addition, the regulated movement of FT protein from the phloem to the shoot apex, and interactions that determine floral meristem cell fate, constitute novel mechanisms through which photoperiodic information is translated into flowering time. PMID:26157354

  4. Gene Coexpression Analysis Reveals Complex Metabolism of the Monoterpene Alcohol Linalool in Arabidopsis Flowers[W][OPEN

    Science.gov (United States)

    Ginglinger, Jean-François; Boachon, Benoit; Höfer, René; Paetz, Christian; Köllner, Tobias G.; Miesch, Laurence; Lugan, Raphael; Baltenweck, Raymonde; Mutterer, Jérôme; Ullmann, Pascaline; Beran, Franziska; Claudel, Patricia; Verstappen, Francel; Fischer, Marc J.C.; Karst, Francis; Bouwmeester, Harro; Miesch, Michel; Schneider, Bernd; Gershenzon, Jonathan; Ehlting, Jürgen; Werck-Reichhart, Danièle

    2013-01-01

    The cytochrome P450 family encompasses the largest family of enzymes in plant metabolism, and the functions of many of its members in Arabidopsis thaliana are still unknown. Gene coexpression analysis pointed to two P450s that were coexpressed with two monoterpene synthases in flowers and were thus predicted to be involved in monoterpenoid metabolism. We show that all four selected genes, the two terpene synthases (TPS10 and TPS14) and the two cytochrome P450s (CYP71B31 and CYP76C3), are simultaneously expressed at anthesis, mainly in upper anther filaments and in petals. Upon transient expression in Nicotiana benthamiana, the TPS enzymes colocalize in vesicular structures associated with the plastid surface, whereas the P450 proteins were detected in the endoplasmic reticulum. Whether they were expressed in Saccharomyces cerevisiae or in N. benthamiana, the TPS enzymes formed two different enantiomers of linalool: (−)-(R)-linalool for TPS10 and (+)-(S)-linalool for TPS14. Both P450 enzymes metabolize the two linalool enantiomers to form different but overlapping sets of hydroxylated or epoxidized products. These oxygenated products are not emitted into the floral headspace, but accumulate in floral tissues as further converted or conjugated metabolites. This work reveals complex linalool metabolism in Arabidopsis flowers, the ecological role of which remains to be determined. PMID:24285789

  5. Transcriptional Consequence and Impaired Gametogenesis with High-Grade Aneuploidy in Arabidopsis thaliana

    OpenAIRE

    Kuan-Lin Lo; Long-Chi Wang; I-Ju Chen; Yu-Chen Liu; Mei-Chu Chung; Wan-Sheng Lo

    2014-01-01

    Aneuploidy features a numerical chromosome variant that the number of chromosomes in the nucleus of a cell is not an exact multiple of the haploid number, which may have an impact on morphology and gene expression. Here we report a tertiary trisomy uncovered by characterizing a T-DNA insertion mutant (aur2-1/+) in the Arabidopsis (Arabidopsis thaliana) AURORA2 locus. Whole-genome analysis with DNA tiling arrays revealed a chromosomal translocation linked to the aur2-1 allele, which collective...

  6. DNA Gyrase Is the Target for the Quinolone Drug Ciprofloxacin in Arabidopsis thaliana*

    Science.gov (United States)

    Evans-Roberts, Katherine M.; Mitchenall, Lesley A.; Wall, Melisa K.; Leroux, Julie; Mylne, Joshua S.; Maxwell, Anthony

    2016-01-01

    The Arabidopsis thaliana genome contains four genes that were originally annotated as potentially encoding DNA gyrase: ATGYRA, ATGYRB1, ATGYRB2, and ATGYRB3. Although we subsequently showed that ATGYRB3 does not encode a gyrase subunit, the other three genes potentially encode subunits of a plant gyrase. We also showed evidence for the existence of supercoiling activity in A. thaliana and that the plant is sensitive to quinolone and aminocoumarin antibiotics, compounds that target DNA gyrase in bacteria. However, it was not possible at that time to show whether the A. thaliana genes encoded an active gyrase enzyme, nor whether that enzyme is indeed the target for the quinolone and aminocoumarin antibiotics. Here we show that an A. thaliana mutant resistant to the quinolone drug ciprofloxacin has a point mutation in ATGYRA. Moreover we show that, as in bacteria, the quinolone-sensitive (wild-type) allele is dominant to the resistant gene. Further we have heterologously expressed ATGYRA and ATGYRB2 in a baculovirus expression system and shown supercoiling activity of the partially purified enzyme. Expression/purification of the quinolone-resistant A. thaliana gyrase yields active enzyme that is resistant to ciprofloxacin. Taken together these experiments now show unequivocally that A. thaliana encodes an organelle-targeted DNA gyrase that is the target of the quinolone drug ciprofloxacin; this has important consequences for plant physiology and the development of herbicides. PMID:26663076

  7. Sucrose amendment enhances phytoaccumulation of the herbicide atrazine in Arabidopsis thaliana

    International Nuclear Information System (INIS)

    Growth in the presence of sucrose was shown to confer to Arabidopsis thaliana (thale cress or mustard weed) seedlings, under conditions of in vitro culture, a high level of tolerance to the herbicide atrazine and to other photosynthesis inhibitors. This tolerance was associated with root-to-shoot transfer and accumulation of atrazine in shoots, which resulted in significant decrease of herbicide levels in the growth medium. In soil microcosms, application of exogenous sucrose was found to confer tolerance and capacity to accumulate atrazine in Arabidopsis thaliana plants grown on atrazine-contaminated soil, and resulted in enhanced decontamination of the soil. Application of sucrose to plants grown on herbicide-polluted soil, which increases plant tolerance and xenobiotic absorption, thus appears to be potentially useful for phytoremediation. - Exogenous sucrose treatment induces plant tolerance to photosystem-targeted herbicides and enhances phytoremediation of herbicide-polluted soil

  8. 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.

  9. Characterization of minisatellites in Arabidopsis thaliana with sequence similarity to the human minisatellite core sequence.

    Science.gov (United States)

    Tourmente, S; Deragon, J M; Lafleuriel, J; Tutois, S; Pélissier, T; Cuvillier, C; Espagnol, M C; Picard, G

    1994-08-25

    A strategy based on random PCR amplification was used to isolate new repetitive elements of Arabidopsis thaliana. One of the random PCR product analyzed by this approach contained a tandem repetitive minisatellite sequence composed of 33 bp repeated units. The genomic locus corresponding to this PCR product was isolated by screening a lambda genomic library. New related loci were also isolated from the genomic library by screening with a 14 mer oligonucleotide representing a region conserved among the different repeated units. Alignment of the consensus sequence for each minisatellite locus allowed the definition of an Arabidopsis thaliana core sequence that shows strong sequence similarities with the human core sequence and with the generalized recombination signal Chi of Escherichia coli. The minisatellites were tested for their ability to detect polymorphism, and their chromosomal position was established. PMID:8078766

  10. 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}.

  11. Unique and redundant functional domains of APETALA1 and CAULIFLOWER, two recently duplicated Arabidopsis thaliana floral MADS-box genes.

    Science.gov (United States)

    Alvarez-Buylla, Elena R; García-Ponce, Berenice; Garay-Arroyo, Adriana

    2006-01-01

    APETALA1 (AP1) and CAULIFLOWER (CAL) are closely related MADS box genes that are partially redundant during Arabidopsis thaliana floral meristem determination. AP1 is able to fully substitute for CAL functions, but not vice versa, and AP1 has unique sepal and petal identity specification functions. In this study, the unique and redundant functions of these two genes has been mapped to the four protein domains that characterize type-II MADS-domain proteins by expressing all 15 chimeric combinations of AP1 and CAL cDNA regions under control of the AP1 promoter in ap1-1 loss-of-function plants. The "in vivo" function of these chimeric genes was analysed in Arabidopsis plants by expressing the chimeras. Rescue of flower meristem and sepal/petal identities was scored in single and multiple insert homozygous transgenic lines. Using these chimeric lines, it was found that distinct residues of the AP1 K domain not shared by the same CAL domain are necessary and sufficient for complete recovery of floral meristem identity, in the context of the CAL protein sequence, while both AP1 COOH and K domains are indispensable for complete rescue of sepal identity. By contrast, either one of these two AP1 domains is necessary and sufficient for complete petal identity recovery. It was also found that there were positive and negative synergies among protein domains and their combinations, and that multiple-insert lines showed relatively better rescue than equivalent single-insert lines. Finally, several lines had flowers with extra sepals and petals suggesting that chimeric proteins yield abnormal transcriptional complexes that may alter the expression or regulation of genes that control floral organ number under normal conditions. PMID:16893974

  12. 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

  13. Electron transfer reactivity of the Arabidopsis thaliana sulfhydryl oxidase AtErv1

    DEFF Research Database (Denmark)

    Farver, Ole; Vitu, Elvira; Wherland, Scot;

    2009-01-01

    The redox reactivity of the three disulfide bridges and the flavin present in each protomer of the wild-type Arabidopsis thaliana mitochondrial sulfhydryl oxidase (AtErv1) homodimer has been investigated. Pulse radiolytically produced CO2- radical ions were found to reduce the disulfide bridges to...... the active site disulfide bridge increased the stability of the flavin semiquinone making it a long-lived product. Relevance of these observations to the design and function of the sulfhydryl oxidases is discussed....

  14. ML3: a novel regulator of herbivory-induced responses in Arabidopsis thaliana

    Czech Academy of Sciences Publication Activity Database

    Fridborg, I.; Johansson, A.; Lagensjo, J.; Leelarasamee, N.; Floková, Kristýna; Tarkowská, Danuše; Meijer, J.; Bejai, S.

    2013-01-01

    Roč. 64, č. 4 (2013), s. 935-948. ISSN 0022-0957 R&D Projects: GA AV ČR KAN200380801 Grant ostatní: GA MŠk(CZ) ED0007/01/01 Institutional research plan: CEZ:AV0Z50380511 Keywords : Arabidopsis thaliana * herbivory * jasmonic acid Subject RIV: EC - Immunology Impact factor: 5.794, year: 2013

  15. Genome-wide comparative analysis of NBS-encoding genes between Brassica species and Arabidopsis thaliana

    OpenAIRE

    Yu, Jingyin; Tehrim, Sadia; Zhang, Fengqi; Tong, Chaobo; Huang, Junyan; Cheng, Xiaohui; Dong, Caihua; Zhou, Yanqiu; Qin, Rui; Hua, Wei; Liu, Shengyi

    2014-01-01

    Background Plant disease resistance (R) genes with the nucleotide binding site (NBS) play an important role in offering resistance to pathogens. The availability of complete genome sequences of Brassica oleracea and Brassica rapa provides an important opportunity for researchers to identify and characterize NBS-encoding R genes in Brassica species and to compare with analogues in Arabidopsis thaliana based on a comparative genomics approach. However, little is known about the evolutionary fat...

  16. A geographic cline in leaf salicylic acid with increasing elevation in Arabidopsis thaliana

    OpenAIRE

    Zhang, Nana; Tonsor, Stephen J; Traw, M. Brian

    2015-01-01

    Salicylic acid (SA) occupies a key role as a hormone central to both plant resistance to bacterial pathogens and tolerance of abiotic stresses. Plants at high elevation experience colder temperatures and elevated UV levels. While it has been predicted that SA concentrations will be higher in plants from high elevation populations, few studies have addressed this question. Here, we asked how concentrations of SA vary in natural populations of Arabidopsis thaliana collected across an elevationa...

  17. Chlorophyll fluorescence emission can screen cold tolerance of cold acclimated Arabidopsis thaliana accessions

    Czech Academy of Sciences Publication Activity Database

    Mishra, Anamika; Heyer, A. G.; Mishra, Kumud

    2014-01-01

    Roč. 10, č. 38 (2014). ISSN 1746-4811 R&D Projects: GA MŠk EE2.3.20.0246; GA MŠk 7E12047 Institutional support: RVO:67179843 Keywords : high-throughput screening * chlorophyll a fluorescence transients * cold tolerance * cold acclimation * whole plant * Arabidopsis thaliana Subject RIV: EH - Ecology, Behaviour Impact factor: 3.102, year: 2014

  18. Enhanced Toxic Metal Accumulation in Engineered Bacterial Cells Expressing Arabidopsis thaliana Phytochelatin Synthase

    OpenAIRE

    Sauge-Merle, Sandrine; Cuiné, Stéphan; Carrier, Patrick; Lecomte-Pradines, Catherine; Luu, Doan-Trung; Peltier, Gilles

    2003-01-01

    Phytochelatins (PCs) are metal-binding cysteine-rich peptides, enzymatically synthesized in plants and yeasts from glutathione in response to heavy metal stress by PC synthase (EC 2.3.2.15). In an attempt to increase the ability of bacterial cells to accumulate heavy metals, the Arabidopsis thaliana gene encoding PC synthase (AtPCS) was expressed in Escherichia coli. A marked accumulation of PCs was observed in vivo together with a decrease in the glutathione cellular content. When bacterial ...

  19. Heterogeneous selection at specific loci in natural environments in Arabidopsis thaliana.

    OpenAIRE

    Weinig, Cynthia; Dorn, Lisa A; Kane, Nolan C.; German, Zachary M; Halldorsdottir, Solveig S; Ungerer, Mark C.; Toyonaga, Yuko; Mackay, Trudy F. C.; Purugganan, Michael D.; Schmitt, Johanna

    2003-01-01

    Genetic variation for quantitative traits is often greater than that expected to be maintained by mutation in the face of purifying natural selection. One possible explanation for this observed variation is the action of heterogeneous natural selection in the wild. Here we report that selection on quantitative trait loci (QTL) for fitness traits in the model plant species Arabidopsis thaliana differs among natural ecological settings and genetic backgrounds. At one QTL, the allele that enhanc...

  20. Funktionsanalyse ausgewählter DOF-Transkriptionsfaktoren bei der Modellpflanze Arabidopsis thaliana

    OpenAIRE

    Skirycz, Aleksandra

    2008-01-01

    Transcription factors (TFs) are global regulators of gene expression playing essential roles in almost all biological processes, and are therefore of great scientific and biotechnological interest. This project focused on functional characterisation of three DNA-binding-with-one-zinc-finger (DOF) TFs from the genetic model plant Arabidopsis thaliana, namely OBP1, OBP2 and AtDOF4;2. These genes were selected due to severe growth phenotypes conferred upon their constitutive over-expression. To ...

  1. Global and targeted proteomics in Arabidopsis thaliana: A study of secondary metabolism and phytohormone signaling

    OpenAIRE

    Slade Jr, William O

    2013-01-01

    Proteomics is defined as a tool to explore how proteins control and regulate important molecular and physiological processes. Further, peptide-centric approaches, or bottom-up methods, provide more comprehensive coverage of a proteome compared to whole-protein approaches. This body of work assesses the technical feasibility of several bottom-up proteomics technologies applied to Arabidopsis thaliana, including gel-based methods, those that require peptide derivitization, and those that do n...

  2. The glutaredoxin ATGRXS13 is required to facilitate Botrytis cinerea infection of Arabidopsis thaliana plants

    OpenAIRE

    Camera, Sylvain La; L’Haridon, Floriane; Astier, Jérémy; Zander, Mark; Abou-Mansour, Eliane; Page, Gonzague; Thurow, Corinna; Wendehenne, David; Gatz, Christiane; Métraux, Jean-Pierre; Lamotte, Olivier

    2011-01-01

    Botrytis cinerea is a major pre- and post-harvest necrotrophic pathogen with a broad host range that causes substantial crop losses. The plant hormone jasmonic acid (JA) is involved in the basal resistance against this fungus. Despite basal resistance, virulent strains of B. cinerea can cause disease on Arabidopsis thaliana and virulent pathogens can interfere with the metabolism of the host in a way to facilitate infection of the plant. However, plant genes that are required by the pathogen ...

  3. Chlorophyll fluorescence emission as a reporter on cold tolerance in Arabidopsis thaliana accessions

    OpenAIRE

    Mishra, Anamika; Mishra, Kumud B; Höermiller, Imke I; Heyer, Arnd G; Nedbal, Ladislav

    2011-01-01

    Non-invasive, high-throughput screening methods are valuable tools in breeding for abiotic stress tolerance in plants. Optical signals such as chlorophyll fluorescence emission can be instrumental in developing new screening techniques. In order to examine the potential of chlorophyll fluorescence to reveal plant tolerance to low temperatures, we used a collection of nine Arabidopsis thaliana accessions and compared their fluorescence features with cold tolerance quantified by the well establ...

  4. Identification of novel regulators of COP1-controlled morphogenesis in Arabidopsis thaliana

    OpenAIRE

    Schrader, Andrea

    2011-01-01

    In Arabidopsis thaliana, COP1 is an essential element of light signal transduction acting downstream of photoreceptors and upstream of light-regulated gene expression. The COP1 protein acts as part of an E3 ligase complex to suppress photomorphogenic gene expression by ubiquitin-dependent degradation of light-regulated transcription factors. In dark-grown seedlings, the repression of photomorphogenesis involves the inhibition of hypocotyl growth, anthocyanin accumulation, expre...

  5. Induction of oxidative stress related responses in Arabidopsis thaliana following uranium exposure

    OpenAIRE

    Vanhoudt, Nathalie; Vandenhove, H.; Opdenakker, Kelly; Remans, Tony; Smeets, Karen; MARTINEZ BELLO, Daniel; van Hees, M.; Wannijn, J.; Vangronsveld, Jaco; Cuypers, Ann

    2009-01-01

    The reactive oxygen species (ROS)-signaling pathway is very important in heavy metal toxicity. Induction of the antioxidative defense mechanism, comprising ROS-scavenging enzymes and metabolites, in plants after environmental uranium contamination has been insufficiently studied in the past. This study aimed to analyze oxidative stress related responses in Arabidopsis thaliana after uranium exposure. Seventeen-day-old seedlings were exposed to 0, 0.1, 1, 10 and 100 μM uranium for 3 days. Afte...

  6. Seed coat mucilage cells of Arabidopsis thaliana as a model for plant cell wall research

    OpenAIRE

    Arsovski, Andrej A; Haughn, George W; Western, Tamara L.

    2010-01-01

    Plant cells are encased within a complex polysaccharide wall that strengthens the cell and has key roles in all aspects of plant cell growth, differentiation and interaction with the environment. This dynamic structure is under continual modification during plant development, and its synthesis and modification require the activity of a myriad of enzymes. The mucilage secretory cells (MSCs) of the Arabidopsis thaliana seed coat provide a model for the discovery of novel genes involved in the s...

  7. Reverse-engineering the Arabidopsis thaliana transcriptional network under changing environmental conditions

    OpenAIRE

    Carrera, Javier; Rodrigo, Guillermo; Jaramillo, Alfonso; Elena, Santiago F.

    2009-01-01

    BACKGROUND: Understanding the molecular mechanisms plants have evolved to adapt their biological activities to a constantly changing environment is an intriguing question and one that requires a systems biology approach. Here we present a network analysis of genome-wide expression data combined with reverse-engineering network modeling to dissect the transcriptional control of Arabidopsis thaliana. The regulatory network is inferred by using an assembly of microarray data containing steady-st...

  8. Dissecting a Hidden Gene Duplication: The Arabidopsis thaliana SEC10 Locus

    Czech Academy of Sciences Publication Activity Database

    Vukašinović, Nemanja; Cvrčková, F.; Eliáš, M.; Cole, R.; Fowler, J.E.; Žárský, Viktor; Synek, Lukáš

    2014-01-01

    Roč. 9, č. 4 (2014). E-ISSN 1932-6203 R&D Projects: GA ČR GPP501/11/P853; GA ČR(CZ) GAP305/11/1629 Grant ostatní: GA MŠk ME10033 Institutional support: RVO:61389030 Keywords : WHOLE-GENOME * ARABIDOPSIS-THALIANA * RECENT SEGMENTAL DUPLICATIONS Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.234, year: 2014

  9. Early cytokinin response proteins and phosphoproteins of Arabidopsis thaliana identified by proteome and phosphoproteome profiling

    Czech Academy of Sciences Publication Activity Database

    Černý, M.; Dyčka, Filip; Bobálová, Janette; Divíšková, E.; Koukalová, Š.; Brzobohatý, B.

    Prague: Czech University of Life Sciences Prague, 2009. s. 34. [ACPD 2009. Auxins and Cytokinins in Plant Development International Symposium. 10.07.2009-14.07.2009, Prague] R&D Projects: GA AV ČR IAA600040701; GA MŠk 1M06030 Institutional research plan: CEZ:AV0Z40310501 Keywords : phosphoproteins * Arabidopsis thaliana * cytokinin Subject RIV: CB - Analytical Chemistry, Separation

  10. Early cytokinin response proteins and phosphoproteins of Arabidopsis thaliana identified by proteome and phosphoproteome profiling

    Czech Academy of Sciences Publication Activity Database

    Černý, M.; Dyčka, Filip; Bobálová, Janette; Divíšková, E.; Brzobohatý, B.; Koukalová, Š.

    Brno: Mendel University of Agriculture and Forestry in Brno, 2009 - (Balla, J.; Reinöhl, V.). s. 50 ISBN 978-80-7375-319-1. [ESNA 2009. 25.08.2009-29.08.2009, Brno] R&D Projects: GA MŠk 1M06030; GA AV ČR IAA600040701 Institutional research plan: CEZ:AV0Z40310501 Keywords : Arabidopsis thaliana * phosphoproteins * cytokinin Subject RIV: CB - Analytical Chemistry, Separation

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

    OpenAIRE

    Warnasooriya, Sankalpi N.; Porter, Katie J.; Montgomery, Beronda L

    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...

  12. Collection of apoplastic fluids from Arabidopsis thaliana leaves

    DEFF Research Database (Denmark)

    Madsen, Svend Roesen; Nour-Eldin, Hussam Hassan; Halkier, Barbara Ann

    2016-01-01

    The leaf apoplast comprises the extracellular continuum outside cell membranes. A broad range of processes take place in the apoplast, including intercellular signaling, metabolite transport, and plant-microbe interactions. To study these processes, it is essential to analyze the metabolite content...... in apoplastic fluids. Due to the fragile nature of leaf tissues, it is a challenge to obtain apoplastic fluids from leaves. Here, methods to collect apoplastic washing fluid and guttation fluid from Arabidopsis thaliana leaves are described....

  13. A kinetic model for the metabolism of the herbicide safener fenclorim in Arabidopsis thaliana

    OpenAIRE

    Liu, Junli; Brazier-Hicks, Melissa; Edwards, Robert

    2009-01-01

    Abstract Glutathione transferases (GSTs) catalyse the detoxification of a range of xenobiotics, including crop protection agents in plants. Recent studies in cultures of the model plant Arabidopsis thaliana have shown that the herbicide safener fenclorim (4,6-dichloro-2-phenylpyrimidine) is conjugated by GSTs acting in the cytosol which are induced in response to this chemical treatment. The primary glutathione conjugates are then hydrolyzed to S-(4-chloro-2-phenylpyrimidin-6-yl)-c...

  14. Proteomic analysis of secreted proteins from Arabidopsis thaliana seedlings: improved recovery following removal of phenolic compounds.

    OpenAIRE

    Charmont, Stéphane; Jamet, Elisabeth; Pont-Lezica, Rafael; Canut, Hervé

    2005-01-01

    Arabidopsis thaliana seedlings grown in liquid culture were used to recover proteins secreted from the whole plant. The aim was to identify apoplastic proteins that may be lost during classical extraction procedures such as preparation of cell walls. The inclusion of polyvinyl-polypyrrolidone (PVPP) in the protocol of purification of secreted proteins allowed a more efficient identification of proteins after their separation by two-dimensional gel electrophoresis (2-DE) and mass spectrometry ...

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

    OpenAIRE

    Truong, Thi Dieu; Bauwens, Julien; Delaplace, Pierre; Mazzucchelli, Gabriel; Lognay, Georges; Francis, Frédéric

    2015-01-01

    Herbivorous insects can cause deep cellular changes to plant foliage following infestations depending on feeding 41 behavior. Here, a proteomic study was conducted to investigate green peach aphid (Myzus persicae Sulzer) 42 influence as a polyphagous pest on the defense response of Arabidopsis thaliana (L.) Heynh after aphid colony 43 set up on host plant (3 days). Analysis of about 574 protein spots on 2-DE gel revealed 31 differentially 44 expressed protein spots. Twenty out of 31 different...

  16. Kontrolle der Expression des UNUSUAL FLORAL ORGANS (UFO) Gens in Arabidopsis thaliana

    OpenAIRE

    Hobe, Martin

    2004-01-01

    Die vorliegende Arbeit befaßt sich mit der Kontrolle des Expressionsmusters des UNUSUAL FLORAL ORGANS (UFO) Gens von Arabidopsis thaliana. UFO wird im Sproß- und Blütenmeristemen aller Entwicklungsstadien der Pflanze exprimiert. In Blütenmeristemen agiert UFO als Kofaktor von LEAFY (LFY) bei der Aktivierung der Organidentitätsgene des zweiten und dritten Wirtels. UFO stellt also einen generellen Faktor der Musterbildung in Meristemen dar. Um regulatorische Gene, die die Expression von UFO bee...

  17. 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; González, María E; 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...

  18. Characterization of minisatellites in Arabidopsis thaliana with sequence similarity to the human minisatellite core sequence.

    OpenAIRE

    Tourmente, S; Deragon, J M; Lafleuriel, J; Tutois, S; Pélissier, T; Cuvillier, C.; Espagnol, M C; G. Picard

    1994-01-01

    A strategy based on random PCR amplification was used to isolate new repetitive elements of Arabidopsis thaliana. One of the random PCR product analyzed by this approach contained a tandem repetitive minisatellite sequence composed of 33 bp repeated units. The genomic locus corresponding to this PCR product was isolated by screening a lambda genomic library. New related loci were also isolated from the genomic library by screening with a 14 mer oligonucleotide representing a region conserved ...

  19. The dominance of the herbicide resistance cost in several Arabidopsis thaliana mutant lines.

    OpenAIRE

    Roux, Fabrice; Gasquez, Jacques; Reboud, Xavier

    2004-01-01

    Resistance evolution depends upon the balance between advantage and disadvantage (cost) conferred in treated and untreated areas. By analyzing morphological characters and simple fitness components, the cost associated with each of eight herbicide resistance alleles (acetolactate synthase, cellulose synthase, and auxin-induced target genes) was studied in the model plant Arabidopsis thaliana. The use of allele-specific PCR to discriminate between heterozygous and homozygous plants was used to...

  20. 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

  1. Funktionelle Charakterisierung zweier Lipid Transfer Proteine in der Arabidopsis thaliana Pathogenantwort

    OpenAIRE

    Bieber, Michael

    2013-01-01

    Die Multigenfamilie der Lipid Transfer Proteine (LTP) stellt eine Gruppe von kleinen Proteinen dar, welche in allen höheren Landpflanzen vorkommen. In der Modellpflanze Arabidopsis thaliana werden 92 Proteine zur Klasse der LTPs gezählt. Die Benennung der Proteinfamilie basiert auf dem beobachteten in vitro Transfer von Lipiden zwischen zwei Membranen. Alle LTPs weisen ein konserviertes, 8 Cysteine beinhaltendes Motiv und eine hydrophobe Tasche auf, welche für die Bindung hydrophober Moleküle...

  2. Analysis of two single trait loci affecting flavonol glycoside accumulations in Arabidopsis thaliana natural variations

    OpenAIRE

    Ishihara, Hirofumi

    2007-01-01

    Various plant secondary metabolites, including flavonoids, are involved in plant adaptation to different environments. The needs of sessile lifestyle of plants may have increased the variation of enzymes which are required in the modification and/or accumulation of different flavonol derivatives. The probable mechanism for generating variants of the enzymes is by mutating the corresponding genes. Therefore, Arabidopsis thaliana wildtype accessions collected from different environments and loc...

  3. Mass spectrometry-based metabolomic fingerprinting for screening cold tolerance in Arabidopsis thaliana accessions

    Czech Academy of Sciences Publication Activity Database

    Václavík, L.; Mishra, Anamika; Mishra, Kumud; Hajslova, J.

    2013-01-01

    Roč. 405, č. 8 (2013), s. 2671-2683. ISSN 1618-2642 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073; GA MŠk OC08055 Institutional support: RVO:67179843 Keywords : cold tolerance * Arabidopsis thaliana * metabolomic fingerprinting * LC-MS * DART-MS * chemometric analysis Subject RIV: EH - Ecology, Behaviour Impact factor: 3.578, year: 2013

  4. Proteomics of loosely bound cell wall proteins of Arabidopsis thaliana cell suspension cultures: a critical analysis.

    OpenAIRE

    Borderies, Gisèle; Jamet, Elisabeth; Lafitte, Claude; Rossignol, Michel; Jauneau, Alain; Boudart, Georges; Monsarrat, Bernard; Esquerré-Tugayé, Marie-Thérèse; Boudet, Alain; Pont-Lezica, Rafael

    2003-01-01

    The complete sequencing of the Arabidopsis thaliana genome allows the use of the recently developed mass spectrometry techniques to identify the cell wall proteins (CWPs). Most proteomic approaches depend on the quality of sample preparation. Extraction of CWPs is particularly complex since the proteins may be free in the apoplast or are embedded in a polysaccharide matrix where they are retained by Van der Waals interactions, hydrogen bonds, hydrophobic or ionic interactions, or cross-linked...

  5. The role of sugars and sugar metabolism genes (sucrose synthase) in arabidopsis thaliana seed development

    OpenAIRE

    Odunlami, Benjamin Oladipo

    2009-01-01

    Seed development in Arabidopsis thaliana, has been studied at several levels. However, little has been done to study the role of sugar metabolism genes in seed pod development in this species. As the fertilized egg progresses to a mature seed, the sugars composition during different stages of the developing changes. These changes are related to metabolic processes in the developing seeds, but also to the activity of sucrose- converting and transporting genes, active at the interphase between ...

  6. Critical evaluation and statistical validation of a hydroponic culture system for Arabidopsis thaliana

    OpenAIRE

    Smeets, Karen; RUYTINX, Joske; Van Belleghem, Frank; Semane, Brahim; Lin, Dan; Vangronsveld, Jaco; Cuypers, Ann

    2008-01-01

    Arabidopsis thaliana is one of the most widely used model organisms in plant sciences. Because of the increasing knowledge in the understanding of its molecular pathways, a reproducible and stable growth set-up for obtaining uniform plants becomes more important. In order to be able to easily harvest and study both roots and shoots, and to allow simple exposure to water-soluble toxic substances, a hydroponic system is the desired cultivation method for controlled plant growth. Based o...

  7. “Rhizoponics”: a novel hydroponic rhizotron for root system analyses on mature Arabidopsis thaliana plants

    OpenAIRE

    Mathieu, Laura; Lobet, Guillaume; Tocquin, Pierre; Périlleux, Claire

    2015-01-01

    Background Well-developed and functional roots are critical to support plant life and reach high crop yields. Their study however, is hampered by their underground growth and characterizing complex root system architecture (RSA) therefore remains a challenge. In the last few years, several phenotyping methods, including rhizotrons and x-ray computed tomography, have been developed for relatively thick roots. But in the model plant Arabidopsis thaliana, in vitro culture remains the easiest and...

  8. Isoflavonoids are present in Arabidopsis thaliana despite the absence of any homologue to known isoflavonoid synthases

    Czech Academy of Sciences Publication Activity Database

    Lapčík, O.; Honys, David; Koblovská, R.; Macková, Z.; Vítková, M.; Klejdus, B.

    2006-01-01

    Roč. 44, 2-3 (2006), s. 106-114. ISSN 0981-9428 R&D Projects: GA ČR GA525/03/0352; GA AV ČR KJB6038409 Institutional research plan: CEZ:AV0Z50380511 Keywords : Arabidopsis thaliana * Brassicaceae * HPLC-MS Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.847, year: 2006

  9. Century-scale Methylome Stability in a Recently Diverged Arabidopsis thaliana Lineage

    OpenAIRE

    Hagmann, J.; Becker, C.; Mueller, J.; Stegle, O.; Meyer, R.; Wang, G; Schneeberger, K.; Fitz, J.; Altmann, T.; J. Bergelson; Borgwardt, K.; Weigel, D.

    2015-01-01

    Author Summary It continues to be hotly debated to what extent environmentally induced epigenetic change is stably inherited and thereby contributes to short-term adaptation. It has been shown before that natural Arabidopsis thaliana lines differ substantially in their methylation profiles. How much of this is independent of genetic changes remains, however, unclear, especially given that there is very little conservation of methylation between species, simply because the methylated sequences...

  10. Activation of nitric oxide synthase and induction of defense genes in Arabidopsis thaliana by bacterial lipopolysaccharides

    OpenAIRE

    Zeidler, Dana

    2006-01-01

    The aim of this study was to examine if Lipopolysaccharide (LPS) are novel elicitors of plant innate immunity using Arabidopsis thaliana as a model system. LPS are the major outer membrane components of Gram-negative bacteria and consist of three distinct structural domains: O-antigen, core region and lipid A. They represent microbe-/pathogen-associated molecular patterns (PAMPs) in animal patho-systems and act as extremely potent stimulators of the mammalian and insect innate immunity. As fo...

  11. Innate immunity in Arabidopsis thaliana: Lipopolysaccharides activate nitric oxide synthase (NOS) and induce defense genes

    OpenAIRE

    Zeidler, Dana; Zähringer, Ulrich; Gerber, Isak; Dubery, Ian; Hartung, Thomas; Bors, Wolf; Hutzler, Peter; Durner, Jörg

    2004-01-01

    Lipopolysaccharides (LPS) are cell-surface components of Gram-negative bacteria and are microbe-/pathogen-associated molecular patterns in animal pathosystems. As for plants, the molecular mechanisms of signal transduction in response to LPS are not known. Here, we show that Arabidopsis thaliana reacts to LPS with a rapid burst of NO, a hallmark of innate immunity in animals. Fifteen LPS preparations (among them Burkholderia cepacia, Pseudomonas aeruginosa, and Erwinia carotovora) as well as ...

  12. Photorespiration mutants of Arabidopsis thaliana deficient in serine-glyoxylate aminotransferase activity

    OpenAIRE

    Somerville, C. R.; Ogren, W L

    1980-01-01

    Three mutants of the crucifer Arabidopsis thaliana (Linnaeus) Heynhold were isolated that are completely lacking in activity catalyzed by serine-glyoxylate aminotransferase (EC 2.6.1.45), a peroxisomal enzyme involved in photorespiratory carbon metabolism. These mutants were viable and exhibited normal photosynthesis under conditions that suppressed photorespiration, but they were inviable and photosynthesized at greatly reduced rates under conditions that promoted photorespiration. Serine an...

  13. Induced Systemic Resistance in Arabidopsis thaliana in Response to Root Inoculation with Pseudomonas fluorescens CHA0

    OpenAIRE

    Iavicoli, Annalisa; Boutet, Emmanuel; Buchala, Antony; Métraux, Jean-Pierre

    2006-01-01

    Root inoculation of Arabidopsis thaliana ecotype Columbia with Pseudomonas fluorescens CHA0r partially protected leaves from the oomycete Peronospora parasitica. The molecular determinants of Pseudomonas fluorescens CHA0r for this induced systemic resistance (ISR) were investigated, using mutants derived from strain CHA0: CHA400 (pyoverdine deficient), CHA805 (exoprotease deficient), CHA77 (HCN deficient), CHA660 (pyoluteorin deficient), CHA631 (2,4-diacetylphloroglucinol [DAPG] deficient), a...

  14. Activity of Antioxidant Enzymes in Response to Cadmium in Arabidopsis thaliana

    OpenAIRE

    A. Saffar; M.B. Bagherieh Najjar; M. Mianabadi

    2009-01-01

    The effects of the heavy metal cadmium (Cd+2) on growth and activities of the antioxidant enzymes, catalase (CAT), peroxidase (POD) and polyphenol oxidase (PPO) have been investigated in Arabidopsis thaliana L. seedlings. The concentration of 50 and 100 μM CdCl2 was shown to strongly inhibit the growth of roots and lipid peroxidation. Lipid peroxidation of seedlings shoots rose with increasing concentrations of Cd+2 as indicated by malondialdehyde (MDA) concentration. As Cd+2 concentra...

  15. Identification of functional domains in Arabidopsis thaliana mRNA decapping enzyme (AtDcp2)

    OpenAIRE

    Gunawardana, Dilantha; Cheng, Heung-Chin; Gayler, Kenwyn R.

    2007-01-01

    The Arabidopsis thaliana decapping enzyme (AtDcp2) was characterized by bioinformatics analysis and by biochemical studies of the enzyme and mutants produced by recombinant expression. Three functionally significant regions were detected: (i) a highly disordered C-terminal region with a putative PSD-95, Discs-large, ZO-1 (PDZ) domain-binding motif, (ii) a conserved Nudix box constituting the putative active site and (iii) a putative RNA binding domain consisting of the conserved Box B and a p...

  16. Routine mapping of Fusarium wilt resistance in BC1 populations of Arabidopsis thaliana

    OpenAIRE

    Andrew C Diener

    2013-01-01

    Abstract Background Susceptibility to Fusarium wilt disease varies among wild accessions of Arabidopsis thaliana. Six RESISTANCE TO FUSARIUM OXYSPORUM (RFO) quantitative trait loci (QTLs) controlling the resistance of accession Columbia-0 (Col-0) and susceptibility of Taynuilt-0 to Fusarium oxysporum forma specialis matthioli (FOM) are detected in a recombinant population derived from a single backcross of the F1 hybrid (BC1). In particular, ...

  17. The Opuntia streptacantha OpsHSP18 Gene Confers Salt and Osmotic Stress Tolerance in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Juan Francisco Jiménez-Bremont

    2012-08-01

    Full Text Available 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.

  18. Regulation of Arabidopsis thaliana Em genes : role of AB15

    NARCIS (Netherlands)

    Carles, C.; Bies-Etheve, N.; Aspart, L.; Léon-Kloosterziel, K.M.; Koornneef, M.; Echeverria, M.; Delseny, M.

    2002-01-01

    In order to identify new factors involved in Em (a class I Late Embryogenesis Abundant protein) gene expression, Arabidopsis mutants with an altered expression of an Em promoter GUS fusion construct and a modified accumulation of Em transcripts and proteins were isolated. Germination tests on ABA sh

  19. The CUP-SHAPED COTYLEDON2 and 3 genes have a post-meristematic effect on Arabidopsis thaliana phyllotaxis

    KAUST Repository

    Burian, Agata

    2015-02-12

    Background and Aims: The arrangement of flowers in inflorescence shoots of Arabidopsis thaliana represents a regular spiral Fibonacci phyllotaxis. However, in the cuc2 cuc3 double mutant, flower pedicels are fused to the inflorescence stem, and phyllotaxis is aberrant in the mature shoot regions. This study examined the causes of this altered development, and in particular whether the mutant phenotype is a consequence of defects at the shoot apex, or whether post-meristematic events are involved. Methods: The distribution of flower pedicels and vascular traces was examined in cross-sections of mature shoots; sequential replicas were used to investigate the phyllotaxis and geometry of shoot apices, and growth of the young stem surface. The expression pattern of CUC3 was analysed by examining its promoter activity. Key Results: Phyllotaxis irregularity in the cuc2 cuc3 double mutant arises during the post-meristematic phase of shoot development. In particular, growth and cell divisions in nodes of the elongating stem are not restricted in the mutant, resulting in pedicel-stem fusion. On the other hand, phyllotaxis in the mutant shoot apex is nearly as regular as that of the wild type. Vascular phyllotaxis, generated almost simultaneously with the phyllotaxis at the apex, is also much more regular than pedicel phyllotaxis. The most apparent phenotype of the mutant apices is a higher number of contact parastichies. This phenotype is associated with increased meristem size, decreased angular width of primordia and a shorter plastochron. In addition, the appearance of a sharp and deep crease, a characteristic shape of the adaxial primordium boundary, is slightly delayed and reduced in the mutant shoot apices. Conclusions: The cuc2 cuc3 double mutant displays irregular phyllotaxis in the mature shoot but not in the shoot apex, thus showing a post-meristematic effect of the mutations on phyllotaxis. The main cause of this effect is the formation of pedicel-stem fusions

  20. Sequence and analysis of chromosome 3 of the plant Arabidopsis thaliana.

    Science.gov (United States)

    Salanoubat, M; Lemcke, K; Rieger, M; Ansorge, W; Unseld, M; Fartmann, B; Valle, G; Blöcker, H; Perez-Alonso, M; Obermaier, B; Delseny, M; Boutry, M; Grivell, L A; Mache, R; Puigdomènech, P; De Simone, V; Choisne, N; Artiguenave, F; Robert, C; Brottier, P; Wincker, P; Cattolico, L; Weissenbach, J; Saurin, W; Quétier, F; Schäfer, M; Müller-Auer, S; Gabel, C; Fuchs, M; Benes, V; Wurmbach, E; Drzonek, H; Erfle, H; Jordan, N; Bangert, S; Wiedelmann, R; Kranz, H; Voss, H; Holland, R; Brandt, P; Nyakatura, G; Vezzi, A; D'Angelo, M; Pallavicini, A; Toppo, S; Simionati, B; Conrad, A; Hornischer, K; Kauer, G; Löhnert, T H; Nordsiek, G; Reichelt, J; Scharfe, M; Schön, O; Bargues, M; Terol, J; Climent, J; Navarro, P; Collado, C; Perez-Perez, A; Ottenwälder, B; Duchemin, D; Cooke, R; Laudie, M; Berger-Llauro, C; Purnelle, B; Masuy, D; de Haan, M; Maarse, A C; Alcaraz, J P; Cottet, A; Casacuberta, E; Monfort, A; Argiriou, A; flores, M; Liguori, R; Vitale, D; Mannhaupt, G; Haase, D; Schoof, H; Rudd, S; Zaccaria, P; Mewes, H W; Mayer, K F; Kaul, S; Town, C D; Koo, H L; Tallon, L J; Jenkins, J; Rooney, T; Rizzo, M; Walts, A; Utterback, T; Fujii, C Y; Shea, T P; Creasy, T H; Haas, B; Maiti, R; Wu, D; Peterson, J; Van Aken, S; Pai, G; Militscher, J; Sellers, P; Gill, J E; Feldblyum, T V; Preuss, D; Lin, X; Nierman, W C; Salzberg, S L; White, O; Venter, J C; Fraser, C M; Kaneko, T; Nakamura, Y; Sato, S; Kato, T; Asamizu, E; Sasamoto, S; Kimura, T; Idesawa, K; Kawashima, K; Kishida, Y; Kiyokawa, C; Kohara, M; Matsumoto, M; Matsuno, A; Muraki, A; Nakayama, S; Nakazaki, N; Shinpo, S; Takeuchi, C; Wada, T; Watanabe, A; Yamada, M; Yasuda, M; Tabata, S

    2000-12-14

    Arabidopsis thaliana is an important model system for plant biologists. In 1996 an international collaboration (the Arabidopsis Genome Initiative) was formed to sequence the whole genome of Arabidopsis and in 1999 the sequence of the first two chromosomes was reported. The sequence of the last three chromosomes and an analysis of the whole genome are reported in this issue. Here we present the sequence of chromosome 3, organized into four sequence segments (contigs). The two largest (13.5 and 9.2 Mb) correspond to the top (long) and the bottom (short) arms of chromosome 3, and the two small contigs are located in the genetically defined centromere. This chromosome encodes 5,220 of the roughly 25,500 predicted protein-coding genes in the genome. About 20% of the predicted proteins have significant homology to proteins in eukaryotic genomes for which the complete sequence is available, pointing to important conserved cellular functions among eukaryotes. PMID:11130713

  1. 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.

  2. 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.

  3. Visualisierung von Plasmamembran-Domänen in Arabidopsis thaliana

    OpenAIRE

    Blachutzik, Jörg O.

    2013-01-01

    Unter Verwendung fluoreszenzmarkierter Remorine der taxonomischen Gruppe 1b wurden Nanodomänen in Arabidopsis Plasmamembranen (PM) unter Verwendung hoch auflösender Laser Scanning-Systeme sichtbar gemacht. In diesen kompartimentierten Membranbereichen lagerten sich Sterol-abhängige Remorine aus verschiedenen Pflanzen-familien zusammen und zeigten dort Kolokalisation. Dies wurde statistisch belegt durch hohe Pearson und Spearman Korrelationskoeffizienten. Remorine konnten schließlich als pflan...

  4. Molecule mechanism of stem cells in Arabidopsis thaliana

    OpenAIRE

    Wenjin Zhang; Rongming Yu

    2014-01-01

    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. S...

  5. Increased Ac excision (iae): Arabidopsis thaliana mutations affecting Ac transposition

    International Nuclear Information System (INIS)

    The maize transposable element Ac is highly active in the heterologous hosts tobacco and tomato, but shows very much reduced levels of activity in Arabidopsis. A mutagenesis experiment was undertaken with the aim of identifying Arabidopsis host factors responsible for the observed low levels of Ac activity. Seed from a line carrying a single copy of the Ac element inserted into the streptomycin phosphotransferase (SPT) reporter fusion, and which displayed typically low levels of Ac activity, were mutagenized using gamma rays. Nineteen mutants displaying high levels of somatic Ac activity, as judged by their highly variegated phenotypes, were isolated after screening the M2 generation on streptomycin-containing medium. The mutations fall into two complementation groups, iae1 and iae2, are unlinked to the SPT::Ac locus and segregate in a Mendelian fashion. The iae1 mutation is recessive and the iae2 mutation is semi-dominant. The iae1 and iae2 mutants show 550- and 70-fold increases, respectively, in the average number of Ac excision sectors per cotyledon. The IAE1 locus maps to chromosome 2, whereas the SPT::Ac reporter maps to chromosome 3. A molecular study of Ac activity in the iae1 mutant confirmed the very high levels of Ac excision predicted using the phenotypic assay, but revealed only low levels of Ac re-insertion. Analyses of germinal transposition in the iae1 mutant demonstrated an average germinal excision frequency of 3% and a frequency of independent Ac re-insertions following germinal excision of 22%. The iae mutants represents a possible means of improving the efficiency of Ac/Ds transposon tagging systems in Arabidopsis, and will enable the dissection of host involvement in Ac transposition and the mechanisms employed for controlling transposable element activity

  6. Does Arabidopsis thaliana DREAM of cell cycle control?

    Science.gov (United States)

    Fischer, Martin; DeCaprio, James A

    2015-08-01

    Strict temporal control of cell cycle gene expression is essential for all eukaryotes including animals and plants. DREAM complexes have been identified in worm, fly, and mammals, linking several distinct transcription factors to coordinate gene expression throughout the cell cycle. In this issue of The EMBO Journal, Kobayashi et al (2015) identify distinct activator and repressor complexes for genes expressed during the G2 and M phases in Arabidopsis that can be temporarily separated during proliferating and post‐mitotic stages of development. The complexes incorporate specific activator and repressor MYB and E2F transcription factors and indicate the possibility of the existence of multiple DREAM complexes in plants. PMID:26089020

  7. Floral Reversion in Arabidopsis suecica Is Correlated with the Onset of Flowering and Meristem Transitioning.

    Directory of Open Access Journals (Sweden)

    Amelia Asbe

    Full Text Available Angiosperm flowers are usually determinate structures that may produce seeds. In some species, flowers can revert from committed flower development back to an earlier developmental phase in a process called floral reversion. The allopolyploid Arabidopsis suecica displays photoperiod-dependent floral reversion in a subset of its flowers, yet little is known about the environmental conditions enhancing this phenotype, or the morphological processes leading to reversion. We have used light and electron microscopy to further describe this phenomenon. Additionally, we have further studied the phenology of flowering and floral reversion in A. suecica. In this study we confirm and expand upon our previous findings that floral reversion in the allopolyploid A. suecica is photoperiod-dependent, and show that its frequency is correlated with the timing for the onset of flowering. Our results also suggest that floral reversion in A. suecica displays natural variation in its penetrance between geographic populations of A. suecica.

  8. Genome wide association mapping for the tolerance to the polyamine oxidase inhibitor guazatine in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Kostadin Evgeniev eAtanasov

    2016-04-01

    Full Text Available Guazatine is a potent inhibitor of polyamine oxidase (PAO activity. In agriculture, guazatine is used as non-systemic contact fungicide efficient in the protection of cereals and citrus fruits against disease. The composition of guazatine is complex, mainly constituted by a mixture of synthetic guanidated polyamines (polyaminoguanidines. Here we have studied the effects from exposure to guazatine in the weed Arabidopsis thaliana. We report that micromolar concentrations of guazatine are sufficient to inhibit growth of Arabidopsis seedlings and induce chlorosis, whereas germination is barely affected. We observed the occurrence of quantitative variation in the response to guazatine between 107 randomly chosen Arabidopsis accessions. This enabled us to undertake genome-wide association (GWA mapping that identified a locus on chromosome one associated with guazatine tolerance. CHLOROPHYLLASE 1 (CLH1 within this locus was studied as candidate gene, together with its paralog (CLH2. The analysis of independent clh1-2, clh1-3, clh2-3, clh2-2 and double clh1-2 clh2-3 mutant alleles indicated that CLH1 and/or CLH2 loss-of-function or expression down-regulation promote guazatine tolerance in Arabidopsis. We report a natural mechanism by which Arabidopsis populations can overcome toxicity by the fungicide guazatine.

  9. Genome Wide Association Mapping for the Tolerance to the Polyamine Oxidase Inhibitor Guazatine in Arabidopsis thaliana.

    Science.gov (United States)

    Atanasov, Kostadin E; Barboza-Barquero, Luis; Tiburcio, Antonio F; Alcázar, Rubén

    2016-01-01

    Guazatine is a potent inhibitor of polyamine oxidase (PAO) activity. In agriculture, guazatine is used as non-systemic contact fungicide efficient in the protection of cereals and citrus fruits against disease. The composition of guazatine is complex, mainly constituted by a mixture of synthetic guanidated polyamines (polyaminoguanidines). Here, we have studied the effects from exposure to guazatine in the weed Arabidopsis thaliana. We report that micromolar concentrations of guazatine are sufficient to inhibit growth of Arabidopsis seedlings and induce chlorosis, whereas germination is barely affected. We observed the occurrence of quantitative variation in the response to guazatine between 107 randomly chosen Arabidopsis accessions. This enabled us to undertake genome-wide association (GWA) mapping that identified a locus on chromosome one associated with guazatine tolerance. CHLOROPHYLLASE 1 (CLH1) within this locus was studied as candidate gene, together with its paralog (CLH2). The analysis of independent clh1-2, clh1-3, clh2-3, clh2-2, and double clh1-2 clh2-3 mutant alleles indicated that CLH1 and/or CLH2 loss-of-function or expression down-regulation promote guazatine tolerance in Arabidopsis. We report a natural mechanism by which Arabidopsis populations can overcome toxicity by the fungicide guazatine. PMID:27092150

  10. 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. PMID:24796562

  11. The COP9 signalosome interacts with SCF UFO and participates in Arabidopsis flower development.

    Science.gov (United States)

    Wang, Xiping; Feng, Suhua; Nakayama, Naomi; Crosby, W L; Irish, Vivian; Deng, Xing Wang; Wei, Ning

    2003-05-01

    The COP9 signalosome (CSN) is involved in multiple developmental processes. It interacts with SCF ubiquitin ligases and deconjugates Nedd8/Rub1 from cullins (deneddylation). CSN is highly expressed in Arabidopsis floral tissues. To investigate the role of CSN in flower development, we examined the expression pattern of CSN in developing flowers. We report here that two csn1 partially deficient Arabidopsis strains exhibit aberrant development of floral organs, decline of APETALA3 (AP3) expression, and low fertility in addition to defects in shoot and inflorescence meristems. We show that UNUSUAL FLORAL ORGANS (UFO) forms a SCF(UFO) complex, which is associated with CSN in vivo. Genetic interaction analysis indicates that CSN is necessary for the gain-of-function activity of the F-box protein UFO in AP3 activation and in floral organ transformation. Compared with the previously reported csn5 antisense and csn1 null mutants, partial deficiency of CSN1 causes a reduction in the level of CUL1 in the mutant flowers without an obvious defect in CUL1 deneddylation. We conclude that CSN is an essential regulator of Arabidopsis flower development and suggest that CSN regulates Arabidopsis flower development in part by modulating SCF(UFO)-mediated AP3 activation. PMID:12724534

  12. 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.

  13. Proteomic alterations in root tips of Arabidopsis thaliana seedlings under altered gravity conditions

    Science.gov (United States)

    Zheng, H. Q.; Wang, H.

    Gravity has a profound influence on plant growth and development Removed the influence of gravitational acceleration by spaceflight caused a wide range of cellular changes in plant Whole seedling that germinated and grown on clinostats showed the absent of gravitropism At the cellular level clinostat treatment has specific effects on plant cells such as induce alterations in cell wall composition increase production of heat-soluble proteins impact on the cellular energy metabolism facilitate a uniform distribution of plastids amyloplasts and increase number and volume of nucleoli A number of recent studies have shown that the exposure of Arabidopsis seedlings and callus cells to gravity stimulation hyper g-forces or clinostat rotation induces alterations in gene expression In our previous study the proteome of the Arabidopsis thaliana callus cells were separated by high resolution two-dimensional electrophoresis 2-DE Image analysis revealed that 80 protein spots showed quantitative and qualitative variations after exposure to clinostat rotation treatment We report here a systematic proteomic approach to investigate the altered gravity responsive proteins in root tip of Arabidopsis thaliana cv Landsberg erecta Three-day-old seedlings were exposed for 12h to a horizontal clinostat rotation H simulated weightlessness altered g-forces by centrifugation 7g hypergravity a vertical clinostat rotation V clinostat control or a stationary control grown conditions Total proteins of roots were extracted

  14. Does Arabidopsis thaliana DREAM of cell cycle control?

    Science.gov (United States)

    Fischer, Martin; DeCaprio, James A

    2015-01-01

    Strict temporal control of cell cycle gene expression is essential for all eukaryotes including animals and plants. DREAM complexes have been identified in worm, fly, and mammals, linking several distinct transcription factors to coordinate gene expression throughout the cell cycle. In this issue of The EMBO Journal, Kobayashi et al (2015) identify distinct activator and repressor complexes for genes expressed during the G2 and M phases in Arabidopsis that can be temporarily separated during proliferating and post-mitotic stages of development. The complexes incorporate specific activator and repressor MYB and E2F transcription factors and indicate the possibility of the existence of multiple DREAM complexes in plants. PMID:26089020

  15. Hormonal relations of radiation-induced tumors of Arabidopsis thaliana

    International Nuclear Information System (INIS)

    When gamma-irradiated Arabidopsis seed was germinated, tumors appeared on hypocotyls and apical meristems of the resulting plants. Several tumors have been cultured on hormone free medium for over two years since excision from the plants. The tumor lines display a range of phenotypes suggestive of abnormal hormone balance. To determine whether hormone overproduction or hypersensitivity is involved in tumorigenesis, we are measuring hormone levels in the tumor lines and characterizing their response to exogenously supplied growth regulators. Growth of two tumor lines is stimulated by either NAA or BAP, one is stimulated by NAA only, two by BAP only, and one is stimulated by neither. Growth of all lines tested thus far is inhibited by gibberellic acid, ethephon and ACC. The tumor lines appear more sensitive to ACC than normal callus tissue. Most tumors studied to date appear unlikely to have arisen due to increased hormone sensitivity. Experiments are in progress to determine auxin and cytokinin levels in the tumor lines

  16. Molecular evolutionary analysis of the Alfin-like protein family in Arabidopsis lyrata, Arabidopsis thaliana, and Thellungiella halophila.

    Directory of Open Access Journals (Sweden)

    Yu Song

    Full Text Available In previous studies, the Alfin1 gene, a transcription factor, enhanced salt tolerance in alfalfa, primarily through altering gene expression levels in the root. Here, we examined the molecular evolution of the Alfin-like (AL proteins in two Arabidopsis species (A. lyrata and A. thaliana and a salt-tolerant close relative Thellungiella halophila. These AL-like proteins could be divided into four groups and the two known DUF3594 and PHD-finger domains had co-evolved within each group of genes, irrespective of species, due to gene duplication events in the common ancestor of all three species while gene loss was observed only in T. halophila. To detect whether natural selection acted in the evolution of AL genes, we calculated synonymous substitution ratios (dn/ds and codon usage statistics, finding positive selection operated on four branches and significant differences in biased codon usage in the AL family between T. halophila and A. lyrata or A. thaliana. Distinctively, only the AL7 branch was under positive selection on the PHD-finger domain and the three members on the branch showed the smallest difference when codon bias was evaluated among the seven clusters. Functional analysis based on transgenic overexpression lines and T-DNA insertion mutants indicated that salt-stress-induced AtAL7 could play a negative role in salt tolerance of A. thaliana, suggesting that adaptive evolution occurred in the members of AL gene family.

  17. Clustering of Pathogen-Response Genesin the Genome of Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    Olga A. Postnikova; Natalia Y. Minakova; Alexander M. Boutanaev; Lev G. Nemchinov

    2011-01-01

    Previously,we used heterologous expressed sequence tag (EST) mapping to generate a profile of 4 935pathogen-response genes of Arabidopsis thaliana.In this work,we performed a computer analysis of this profile,revealing 1 594 non-homologous clustered genes distributed among all A.thaliana chromosomes,whose co-regulation may be related to host responses to pathogens.To supplement computer data,we arbitrarily selected two clusters and analyzed their expression levels in A.thaliana ecotypes Col-0and C24 during infection with the yellow strain of Cucumber mosaic virus CMV(Y).Ecotype Col-0 is susceptible to CMV(Y),whereas C24 contains the dominant resistance gene RCY1.Upon infection with CMV(Y),all clustered genes were significantly activated in the resistant ecotype C24.In addition,we demonstrated that posttranslational histone modifications associated with trimethylation of histone H3 lysine 27 are most likely involved in regulation of several cluster genes described in this study.Overall,our experiments indicated that pathogen-response genes in the genome of A.thaliana may be clustered and co-regulated.

  18. The WD40 repeat protein NEDD1 functions in microtubule organization during cell division in Arabidopsis thaliana.

    Science.gov (United States)

    Zeng, C J Tracy; Lee, Y-R Julie; Liu, Bo

    2009-04-01

    Although cells of flowering plants lack a structurally defined microtubule-organizing center like the centrosome, organization of the spindles and phragmoplasts in mitosis is known to involve the evolutionarily conserved gamma-tubulin complex. We have investigated the function of Arabidopsis thaliana NEDD1, a WD40 repeat protein related to the animal NEDD1/GCP-WD protein, which interacts with the gamma-tubulin complex. The NEDD1 protein decorates spindle microtubules (MTs) preferentially toward spindle poles and phragmoplast MTs toward their minus ends. A T-DNA insertional allele of the single NEDD1 gene was isolated and maintained in heterozygous sporophytes, and NEDD1's function in cell division was analyzed in haploid microspores produced by the heterozygote. In approximately half of the dividing microspores exhibiting aberrant MT organization, spindles were no longer restricted to the cell periphery and became abnormally elongated. After mitosis, MTs aggregated between reforming nuclei but failed to appear in a bipolar configuration. Consequently, defective microspores did not form a continuous cell plate, and two identical nuclei were produced with no differentiation into generative and vegetative cells. Our results support the notion that the plant NEDD1 homolog plays a critical role in MT organization during mitosis, and its function is likely linked to that of the gamma-tubulin complex. PMID:19383896

  19. 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; Knecht, Wolfgang; Rozpedowska, Elzbieta; Sandrini, Michael Paolo; Andreasson, Erik; Munch-Petersen, Birgitte; Piskur, Jure

    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...

  20. 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; Knecht, Wolfgang; Rozpedowska, Elzbieta; Sandrini, Michael; Andreasson, Erik; Munch‐Petersen, Birgitte; Piskur, Jure

    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...

  1. Allelopathic Effects of Plant-Derived Aerosol Smoke on Seed Germination of Arabidopsis thaliana (L.) Heynh

    International Nuclear Information System (INIS)

    The role that plant-derived smoke plays in promoting seed germination is well documented, but little is known about its ability to inhibit seed germination. To better understand this phenomenon, we tested the effects of eight aerosol smoke treatments on the Columbia-3 ecotype of non dormant Arabidopsis thaliana (L.) Heynh. seeds. Our results revealed that aerosol smoke significantly inhibits germination when seeds were exposed to prolonged periods of aerosol smoke. Short durations of smoke treatments significantly promoted the rate of germination of A. thaliana seed. We briefly discuss this dual regulation of smoke and its possible impact on conservation and restoration practices. We also propose that plant-derived smoke may be another vehicle by which allelo chemicals can be introduced into the environment.

  2. 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.

  3. Crystallization and preliminary X-ray analysis of tubulin-folding cofactor A from Arabidopsis thaliana

    International Nuclear Information System (INIS)

    Tubulin-folding cofactor A from A. thaliana has been crystallized and preliminarily analyzed using X-ray diffraction. Tubulin-folding cofactor A (TFC A) is a molecular post-chaperonin that is involved in the β-tubulin-folding pathway. It has been identified in many organisms including yeasts, humans and plants. In this work, Arabidopsis thaliana TFC A was expressed in Escherichia coli and purified to homogeneity. After thrombin cleavage, a well diffracting crystal was obtained by the sitting-drop vapour-diffusion method at 289 K. The crystal diffracted to 1.6 Å resolution using synchrotron radiation and belonged to space group I41, with unit-cell parameters a = 55.0, b = 55.0, c = 67.4 Å

  4. Expression of recombinant human anti-TNF-α scFv-Fc in Arabidopsis thaliana seeds.

    Science.gov (United States)

    Yao, N; Ai, L; Dong, Y Y; Liu, X M; Wang, D Z; Wang, N; Li, X W; Wang, F W; Li, Xk; Li, H Y; Jiang, C

    2016-01-01

    Recombinant human anti-tumor necrosis factor (TNF)-α scFv-Fc was expressed in TKO mutant Arabidopsis thaliana seeds using plant-specific codons. Immunoblotting using a human IgG1 antibody detected the expression of anti-TNF-α proteins in plants. Results from qRT-PCR analysis demonstrated that the time of harvest significantly affected the protein yield and quality. Our results indicate that the Phaseolus vulgaris β-phaseolin promoter directed anti-TNF-α scFv-Fc expression in A. thaliana seeds, with a maximum yield obtained at 20-days of development. Although the yield of anti-TNF-α scFv-Fc protein was not very high, accumulation of recombinant proteins in seeds is an attractive and simple method that can be used to purify biologically active anti-TNF-α scFv-Fc. PMID:27420937

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

    Directory of Open Access Journals (Sweden)

    Ilona Turek

    2015-09-01

    Full Text Available 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.

  6. 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.

  7. Defects in leaf epidermis of Arabidopsis thaliana plants with CDKA;1 activity reduced in the shoot apical meristem

    OpenAIRE

    Borowska-Wykret, Dorota; Elsner, Joanna; De Veylder, Lieven; Kwiatkowska, Dorota

    2012-01-01

    In Arabidopsis thaliana, like in other dicots, the shoot epidermis originates from protodermis, the outermost cell layer of shoot apical meristem. We examined leaf epidermis in transgenic A. thaliana plants in which CDKA;1.N146, a negative dominant allele of A-type cyclin-dependent kinase, was expressed from the SHOOTMERISTEMLESS promoter, i.e., in the shoot apical meristem. Using cleared whole mount preparations of expanding leaves and sequential in vivo replicas of expanding leaf surface, w...

  8. Differences in photosynthesis and terpene content in leaves and roots of wild-type and transgenic Arabidopsis thaliana plants

    OpenAIRE

    Blanch Roure, Josep-Salvador; Peñuelas, Josep; Llusià Benet, Joan; Sardans i Galobart, Jordi; Owen, Susan M.

    2015-01-01

    We investigated the hypotheses that two different varieties of Arabidopsis thaliana show differences in physiology and terpene production. The two varieties of A. thaliana used in this study were wildtype (WT) and transgenic line (CoxIVFaNES I) genetically modified to emit nerolidol with linalool/nerolidol synthase (COX). Photosynthetic rate, electron transport rate, fluorescence, leaf volatile terpene contents and root volatile terpene contents were analyzed. For both types, we found coeluti...

  9. Compensatory expression and substrate inducibility of γ-glutamyl transferase GGT2 isoform in Arabidopsis thaliana

    OpenAIRE

    Destro, Tiziana; Prasad, Dinesh; Martignago, Damiano; Lliso Bernet, Ignacio; Trentin, Anna Rita; Renu, Indu Kumari; Ferretti, Massimo; Masi, Antonio

    2010-01-01

    γ-Glutamyl transferases (GGT; EC 2.3.2.2) are glutathione-degrading enzymes that are represented in Arabidopsis thaliana by a small gene family of four members. Two isoforms, GGT1 and GGT2, are apoplastic, sharing broad similarities in their amino acid sequences, but they are differently expressed in the tissues: GGT1 is expressed in roots, leaves, and siliques, while GGT2 was thought to be expressed only in siliques. It is demonstrated here that GGT2 is also expressed in wild-type roots, alb...

  10. Germination of arabidopsis thaliana seeds irradiated by MeV ions

    International Nuclear Information System (INIS)

    Dry seeds of Arabidopsis thaliana were irradiated with F ions and H ions with the energy range from keV to MeV, respectively. The inhibition of germination was investigated to display the influences of ion mass, energy and fluence. The results show that H ion irradiation is more effective in decreasing the germination rate than heavier F ion irradiation. After irradiation of F ions, a decrease-increase-decease type of germination rate-fluence response curve was found and the ion fluence at the peak position decreases with ion energy increase. The possible mechanism of above experimental results is discussed in this paper. (authors)

  11. Hydrogen peroxide is involved in cGMP modulating the lateral root development of Arabidopsis thaliana

    OpenAIRE

    Li, Jisjeng; Jia, Honglei

    2013-01-01

    3′,5′-cyclic guanosine monophosphate (cGMP) and hydrogen peroxide (H2O2) function as the important signaling molecule which promote the lateral root development of Arabidopsis thaliana. In this study, interestingly, application of 8-Br-cGMP (the membrane permeable cGMP analog) promoted the endogenous H2O2 production. In addition, the decrease of endogenous H2O2 also inhibited the effect of cGMP on the lateral root development. Thus, H2O2 maybe act as a downstream signaling of cGMP molecule wh...

  12. 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...... key 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....

  13. Arabidopsis thaliana GYRB3 Does Not Encode a DNA Gyrase Subunit

    OpenAIRE

    Evans-Roberts, Katherine M.; Christian Breuer; Wall, Melisa K.; Keiko Sugimoto-Shirasu; Anthony Maxwell

    2010-01-01

    Background DNA topoisomerases are enzymes that control the topology of DNA in all cells. DNA gyrase is unique among the topoisomerases in that it is the only enzyme that can actively supercoil DNA using the free energy of ATP hydrolysis. Until recently gyrase was thought to be unique to bacteria, but has now been discovered in plants. The genome of the model plant, Arabidopsis thaliana, is predicted to encode four gyrase subunits: AtGyrA, AtGyrB1, AtGyrB2 and AtGyrB3. Methodology/Principal Fi...

  14. Die Untersuchung der pflanzlichen Organellentranskription am Beispiel der kernkodierten RNA-Polymerasen in Arabidopsis thaliana

    OpenAIRE

    Hensel, Sarah-Sophia Nicola

    2010-01-01

    In Arabidopsis thaliana three nucleus-encoded phagetype RNA polymerases (RpoT;1, RpoT;2 and RpoT;3) were cloned. They show a conserved gene structure and have up to 55% aminoacid homology. By means of in organelle-import approaches and by using GFP-fusion-proteins, the localization of these three enzymes in different organelles was possible. Therefore RpoT;1 is only needed in mitochondria, RpoT;3 is targeted to plastids. In contrast to this, RNA polymerase 2 (RpoT;2) is imported in both plast...

  15. Early cytokinin response proteins and phosphoproteins of Arabidopsis thaliana identified by proteome and phosphoproteome profiling

    Czech Academy of Sciences Publication Activity Database

    Černý, M.; Dyčka, Filip; Bobálová, Janette; Brzobohatý, Břetislav

    2011-01-01

    Roč. 62, č. 3 (2011), s. 921-937. ISSN 0022-0957 R&D Projects: GA MŠk(CZ) LC06034; GA MŠk(CZ) 1M06030; GA AV ČR IAA600040701; GA ČR(CZ) GA206/09/2062 Institutional research plan: CEZ:AV0Z40310501; CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : Arabidopsis thaliana * cytokinin * phosphoproteome * proteome Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 5.364, year: 2011

  16. 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...... partial pressure of the petiole and root had stabilized at c. 6 and 0.1 kPa, respectively. As controls, plants were untreated or exposed to darkness. Following quantitative profiling of cellular mRNAs with the Affymetrix ATH1 platform, changes in the transcriptome in response to submergence, early...

  17. Endocytosis and degradation of BOR1, a boron transporter of Arabidopsis thaliana, regulated by boron availability

    OpenAIRE

    Takano, Junpei; Miwa, Kyoko; Yuan, Lixing; von Wirén, Nicolaus; Fujiwara, Toru

    2005-01-01

    Boron (B) is essential for plants but toxic when present in excess. Arabidopsis thaliana BOR1 is a B exporter for xylem loading and is essential for efficient B translocation from roots to shoots under B limitation. B translocation to shoots was enhanced under B limitation in WT but not in bor1-1 mutant plants. The enhanced translocation was suppressed upon resupply of high levels of B within several hours. Unlike a number of transporters for essential mineral nutrients, BOR1 mRNA accumulatio...

  18. Individual Leaf Development in Arabidopsis thaliana: a Stable Thermal‐time‐based Programme

    OpenAIRE

    GRANIER, CHRISTINE; Massonnet, Catherine; TURC, OLIVIER; Muller, Bertrand; Chenu, Karine; Tardieu, François

    2002-01-01

    In crop species, the impact of temperature on plant development is classically modelled using thermal time. We examined whether this method could be used in a non‐crop species, Arabidopsis thaliana, to analyse the response to temperature of leaf initiation rate and of the development of two leaves of the rosette. The results confirmed the large plant‐to‐plant variability in the studied isogenic line of the Columbia ecotype: 100‐fold differences in leaf area among plants sown on the same date ...

  19. Expression and detection of the FMDV VP1 transgene and expressed structural protein in Arabidopsis thaliana

    OpenAIRE

    Pan, Li; Zhang, Yongguang; Wang, Yonglu; Lv, Jianliang; Zhou, Peng; Zhang, Zhongwang

    2011-01-01

    To explore the feasibility of developing a new type of plantderived foot-and-mouth disease virus (FMDV) oral vaccine, the plant seed-specific expression vector p7SBin438/VP1 carrying the VP1 gene of the FMDV strain O/China/99 was constructed and transformed into Agrobacterium tumefaciens strain GV3101. This strain was used for transformation of Arabidopsis thaliana via the floral-dip method. The kanamycin-resistant transgenic plants were selected, and the VP1 gene and protein expressions were...

  20. Unique Features of the m6A Methylome in Arabidopsis thaliana

    OpenAIRE

    Luo, Guan-Zheng; MacQueen, Alice; Zheng, Guanqun; Duan, Hongchao; Dore, Louis C; Lu, Zhike; LIU Jun; Chen, Kai; Jia, Guifang; Bergelson, Joy; He, Chuan

    2014-01-01

    Recent discoveries of reversible N 6-methyladenosine (m6A) methylation on messenger RNA (mRNA) and mapping of m6A methylomes in mammals and yeast have revealed potential regulatory functions of this RNA modification. In plants, defects in m6A methyltransferase cause an embryo-lethal phenotype, suggesting a critical role of m6A in plant development. Here, we profile m6A transcriptome-wide in two accessions of Arabidopsis thaliana and reveal that m6A is a highly conserved modification of mRNA i...

  1. 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.

  2. Arabidopsis thaliana auxotrophs reveal a tryptophan-independent biosynthetic pathway for indole-3-acetic acid.

    OpenAIRE

    Normanly, J; Cohen, J D; Fink, G. R.

    1993-01-01

    We used tryptophan auxotrophs of the dicot Arabidopsis thaliana (wall cress) to determine whether tryptophan has the capacity to serve as a precursor to the auxin, indole-3-acetic acid (IAA). Quantitative gas chromatography-selected ion monitoring-mass spectrometry (GC-SIM-MS) revealed that the trp2-1 mutant, which is defective in the conversion of indole to tryptophan, accumulated amide- and ester-linked IAA at levels 38-fold and 19-fold, respectively, above those of the wild type. Tryptopha...

  3. Nuclear activity of ROXY1, a glutaredoxin interacting with TGA factors, is required for petal development in Arabidopsis thaliana.

    Science.gov (United States)

    Li, Shutian; Lauri, Andrea; Ziemann, Mark; Busch, Andrea; Bhave, Mrinal; Zachgo, Sabine

    2009-02-01

    Glutaredoxins (GRXs) have thus far been associated mainly with redox-regulated processes participating in stress responses. However, ROXY1, encoding a GRX, has recently been shown to regulate petal primorida initiation and further petal morphogenesis in Arabidopsis thaliana. ROXY1 belongs to a land plant-specific class of GRXs that has a CC-type active site motif, which deviates from ubiquitously occurring CPYC and CGFS GRXs. Expression studies of yellow fluorescent protein-ROXY1 fusion genes driven by the cauliflower mosaic virus 35S promoter reveal a nucleocytoplasmic distribution of ROXY1. We demonstrate that nuclear localization of ROXY1 is indispensable and thus crucial for its activity in flower development. Yeast two-hybrid screens identified TGA transcription factors as interacting proteins, which was confirmed by bimolecular fluorescence complementation experiments showing their nuclear interaction in planta. Overlapping expression patterns of ROXY1 and TGA genes during flower development demonstrate that ROXY1/TGA protein interactions can occur in vivo and support their biological relevance in petal development. Deletion analysis of ROXY1 demonstrates the importance of the C terminus for its functionality and for mediating ROXY1/TGA protein interactions. Phenotypic analysis of the roxy1-2 pan double mutant and an engineered chimeric repressor mutant from PERIANTHIA (PAN), a floral TGA gene, supports a dual role of ROXY1 in petal development. Together, our results show that the ROXY1 protein functions in the nucleus, likely by modifying PAN posttranslationally and thereby regulating its activity in petal primordia initiation. Additionally, ROXY1 affects later petal morphogenesis, probably by modulating other TGA factors that might act redundantly during differentiation of second whorl organs. PMID:19218396

  4. Life-cycle chronic gamma exposure of Arabidopsis thaliana induces growth effects but no discernable effects on oxidative stress pathways.

    Science.gov (United States)

    Vandenhove, Hildegarde; Vanhoudt, Nathalie; Cuypers, Ann; van Hees, May; Wannijn, Jean; Horemans, Nele

    2010-09-01

    Arabidopsis thaliana was exposed to low-dose chronic gamma irradiation during a full life cycle (seed to seed) and several biological responses were investigated. Applied dose rates were 2336, 367 and 81 microGy h(-1). Following 24 days (inflorescence emergence), 34 days (approximately 50% of flowers open) and 54 days (silice ripening) exposure, plants were harvested and monitored for biometric parameters, capacities of enzymes involved in the antioxidative defence mechanisms (SOD, APOD, GLUR, GPOD, SPOD, CAT, ME), glutathione and ascorbate pool, lipid peroxidation products, altered gene expression of selected genes encoding for antioxidative enzymes or reactive oxygen species production, and DNA integrity. Root fresh weight was significantly reduced after gamma exposure compared to the control at all stages monitored but no significant differences in root weight for the different dose rates applied was observed. Leaf and stem fresh weight were significantly reduced at the highest irradiation level after 54 days exposure only. Also total plant fresh was significantly lower at silice riping and this for the highest and medium dose rate applied. The dose rate estimated to result in a 10% reduction in growth (EDR-10) ranged between 60 and 80 microGy h(-1). Germination of seeds from the gamma irradiated plants was not hampered. For several of the antioxidative defence enzymes studied, the enzyme capacity was generally stimulated towards flowering but generally no significant effect of dose rate on enzyme capacity was observed. Gene analysis revealed a significant transient and dose dependent change in expression of RBOHC indicating active reactive oxygen production induced by gamma irradiation. No effect of irradiation was observed on concentration or reduction state of the non-enzymatic antioxidants, ascorbate and glutathione. The level of lipid peroxidation products remained constant throughout the observation period and was not affected by dose rate. The comet assay

  5. UV- and gamma-radiation sensitive mutants of Arabidopsis thaliana

    International Nuclear Information System (INIS)

    Arabidopsis seedlings repair UV-induced DNA damage via light-dependent and -independent pathways. The mechanism of the ''dark repair'' pathway is still unknown. To determine the number of genes required for dark repair and to investigate the substrate-specificity of this process we isolated mutants with enhanced sensitivity to UV radiation in the absence of photoreactivating light. Seven independently derived UV sensitive mutants were isolated from an EMS-mutagenized population. These fell into six complementation groups, two of which (UVR1 and UVH1) have previously been defined. Four of these mutants are defective in the dark repair of UV-induced pyrimidine [6-4] pyrimidinone dimers. These four mutant lines are sensitive to the growth-inhibitory effects of gamma radiation, suggesting that this repair pathway is also involved in the repair of some type of gamma-induced DNA damage product. The requirement for the coordinate action of several different gene products for effective repair of pyrimidine dimers, as well as the nonspecific nature of the repair activity, is consistent with nucleotide excision repair mechanisms previously described in Saccharomyces cerevisiae and nonplant higher eukaryotes and inconsistent with substrate-specific base excision repair mechanisms found in some bacteria, bacteriophage, and fungi. (author)

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

    Directory of Open Access Journals (Sweden)

    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.

  7. Structure and Function of Centromeric and Pericentromeric Heterochromatin in Arabidopsis thaliana

    Science.gov (United States)

    Simon, Lauriane; Voisin, Maxime; Tatout, Christophe; Probst, Aline V.

    2015-01-01

    The centromere is a specific chromosomal region where the kinetochore assembles to ensure the faithful segregation of sister chromatids during mitosis and meiosis. Centromeres are defined by a local enrichment of the specific histone variant CenH3 mostly at repetitive satellite sequences. A larger pericentromeric region containing repetitive sequences and transposable elements surrounds the centromere that adopts a particular chromatin state characterized by specific histone variants and post-translational modifications and forms a transcriptionally repressive chromosomal environment. In the model organism Arabidopsis thaliana centromeric and pericentromeric domains form conspicuous heterochromatin clusters called chromocenters in interphase. Here we discuss, using Arabidopsis as example, recent insight into mechanisms involved in maintenance and establishment of centromeric and pericentromeric chromatin signatures as well as in chromocenter formation. PMID:26648952

  8. 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....... By germinating the lines in a medium containing the nitric oxide (NO) donor, sodium nitroprusside (SNP), it was demonstrated that both GLB1 and GLB2 promote bolting by antagonizing the effect of NO, suggesting that non-symbiotic plant hemoglobin controls bolting by scavenging the floral transition...... with an optimum at low concentrations. It was observed that overexpression of either GLB1 or GLB2 shifts the optimum for NO growth stimulation to a higher concentration. In conclusion, we have found that expression of NO scavenging plant hemoglobin is involved in the control of bolting in Arabidopsis....

  9. Arabidopsis thaliana - Myzus persicae interaction: shaping the understanding of plant defense against phloem-feeding aphids

    Directory of Open Access Journals (Sweden)

    Joe eLouis

    2013-07-01

    Full Text Available The phloem provides a unique niche for several organisms. Aphids are a large group of Hemipteran insects that utilize stylets present in their mouthparts to pierce sieve elements and drink large volumes of phloem sap. In addition, many aphids also vector viral diseases. Myzus persicae, commonly known as the green peach aphid (GPA, is an important pest of a large variety of plants that includes Arabidopsis thaliana. This review summarizes recent studies that have exploited the compatible interaction between Arabidopsis and GPA to understand the molecular and physiological mechanisms utilized by plants to control aphid infestation, as well as genes and mechanisms that contribute to susceptibility. In addition, recent efforts to identify aphid-delivered elicitors of plant defenses and novel aphid salivary components that facilitate infestation are also discussed.

  10. Protein expression and characterization of SEP3 from Arabidopsis thaliana.

    Science.gov (United States)

    Shi, Q; Zhou, J; Wang, P; Lin, X; Xu, Y

    2015-01-01

    SEPALLATA (SEP) MADS-box genes play crucial roles in the regulation of floral growth and development. They are required for the specification of sepals, petals, stamens, and carpels as well as for floral determinacy. SEPs perform their functions through the formation of homo- or hetero-polymers, which are the molecular basis of floral quartets. In vitro assays indicated that SEP3 forms a tetramer after binding to DNA, but it is unclear whether DNA binding induces the tetramer, because SEP3 is often reported to form a dimer. Here, we analyzed the oligomeric status of SEP3 domains in the absence of the DNA-binding MADS-box domain. The truncated SEP3 was constructed as a fusion protein and expressed in prokaryotic cells. The purified protein fragment displayed as a tetramer in the size exclusion chromatographic column, and a glutaraldehyde cross-linking assay demonstrated that the protein contained a dimer unit. Yeast two-hybrid tests further verified that the fragments form homologous polymers in vivo, and that the K domain is involved in tetramer formation. Current results imply that the SEP3 protein regulates the formation of flower meristems using the tetramer as a unit, and that the DNA-binding MADS-box is dispensable for polymer formation. The C-terminal region does not contribute to homo-tetramer formation, but it may be reserved to glue other proteins. PMID:26505403

  11. 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.

  12. Molecular signatures in Arabidopsis thaliana in response to insect attack and bacterial infection.

    Directory of Open Access Journals (Sweden)

    Pankaj Barah

    Full Text Available BACKGROUND: Under the threat of global climatic change and food shortages, it is essential to take the initiative to obtain a comprehensive understanding of common and specific defence mechanisms existing in plant systems for protection against different types of biotic invaders. We have implemented an integrated approach to analyse the overall transcriptomic reprogramming and systems-level defence responses in the model plant species Arabidopsis thaliana (A. thaliana henceforth during insect Brevicoryne brassicae (B. brassicae henceforth and bacterial Pseudomonas syringae pv. tomato strain DC3000 (P. syringae henceforth attacks. The main aim of this study was to identify the attacker-specific and general defence response signatures in A. thaliana when attacked by phloem-feeding aphids or pathogenic bacteria. RESULTS: The obtained annotated networks of differentially expressed transcripts indicated that members of transcription factor families, such as WRKY, MYB, ERF, BHLH and bZIP, could be crucial for stress-specific defence regulation in Arabidopsis during aphid and P. syringae attack. The defence response pathways, signalling pathways and metabolic processes associated with aphid attack and P. syringae infection partially overlapped. Components of several important biosynthesis and signalling pathways, such as salicylic acid (SA, jasmonic acid (JA, ethylene (ET and glucosinolates, were differentially affected during the two the treatments. Several stress-regulated transcription factors were known to be associated with stress-inducible microRNAs. The differentially regulated gene sets included many signature transcription factors, and our co-expression analysis showed that they were also strongly co-expressed during 69 other biotic stress experiments. CONCLUSIONS: Defence responses and functional networks that were unique and specific to aphid or P. syringae stresses were identified. Furthermore, our analysis revealed a probable link between

  13. Insertion DNA Accelerates Meiotic Interchromosomal Recombination in Arabidopsis thaliana.

    Science.gov (United States)

    Sun, Xiao-Qin; Li, Ding-Hong; Xue, Jia-Yu; Yang, Si-Hai; Zhang, Yan-Mei; Li, Mi-Mi; Hang, Yue-Yu

    2016-08-01

    Nucleotide insertions/deletions are ubiquitous in eukaryotic genomes, and the resulting hemizygous (unpaired) DNA has significant, heritable effects on adjacent DNA. However, little is known about the genetic behavior of insertion DNA. Here, we describe a binary transgenic system to study the behavior of insertion DNA during meiosis. Transgenic Arabidopsis lines were generated to carry two different defective reporter genes on nonhomologous chromosomes, designated as "recipient" and "donor" lines. Double hemizygous plants (harboring unpaired DNA) were produced by crossing between the recipient and the donor, and double homozygous lines (harboring paired DNA) via self-pollination. The transfer of the donor's unmutated sequence to the recipient generated a functional β-glucuronidase gene, which could be visualized by histochemical staining and corroborated by polymerase chain reaction amplification and sequencing. More than 673 million seedlings were screened, and the results showed that meiotic ectopic recombination in the hemizygous lines occurred at a frequency  >6.49-fold higher than that in the homozygous lines. Gene conversion might have been exclusively or predominantly responsible for the gene correction events. The direct measurement of ectopic recombination events provided evidence that an insertion, in the absence of an allelic counterpart, could scan the entire genome for homologous counterparts with which to pair. Furthermore, the unpaired (hemizygous) architectures could accelerate ectopic recombination between itself and interchromosomal counterparts. We suggest that the ectopic recombination accelerated by hemizygous architectures may be a general mechanism for interchromosomal recombination through ubiquitously dispersed repeat sequences in plants, ultimately contributing to genetic renovation and eukaryotic evolution. PMID:27189569

  14. Defining the Functional Network of Epigenetic Regulators in Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    Chongyuan Luo; Brittany G.Durgin; Naohide Watanabe; Eric Lam

    2009-01-01

    Development of ChiP-chip and ChlP-seq technologies has allowed genome-wide high-resolution profiling of chromatin-associated marks and binding sites for epigenetic regulators.However,signals for directing epigenetic modi fiers to their target sites are not understood.In this paper,we tested the hypothesis that genome location can affect the involvement of epigenetic regulators using Chromatin Charting (CC) Lines,which have an identical transgene construct inserted at different locations in the Arabidopsis genome.Four CC lines that showed evidence for epigenetic silencing of the luciferase reporter gene were transformed with RNAi vectors individually targeting epigenetic regulators LHP1,MOM1,CMT3,DRD1,DRM2,SUVH2,CLF,and HD1.Involvement of a particular epigenetic regulator in silencing the transgene locus in a CC line was determined by significant alterations in luciferase expression after suppression of the regulator's expression.Our results suggest that the targeting of epigenetic regulators can be influenced by genome location as well as sequence context.In addition,the relative importance of an epigenetic regulator can be influenced by tissue identity.We also report a novel approach to predict interactions between epigenetic regulators through clustering analysis of the regulators using alterations in gene expression of putative downstream targets,including endogenous loci and transgenes,in epigenetic mutants or RNAi lines.Our data support the existence of a complex and dynamic network of epigenetic regulators that serves to coordinate and control global gene expression in higher plants.

  15. Genetic basis for dosage sensitivity in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Isabelle M Henry

    2007-04-01

    Full Text Available Aneuploidy, the relative excess or deficiency of specific chromosome types, results in gene dosage imbalance. Plants can produce viable and fertile aneuploid individuals, while most animal aneuploids are inviable or developmentally abnormal. The swarms of aneuploid progeny produced by Arabidopsis triploids constitute an excellent model to investigate the mechanisms governing dosage sensitivity and aneuploid syndromes. Indeed, genotype alters the frequency of aneuploid types within these swarms. Recombinant inbred lines that were derived from a triploid hybrid segregated into diploid and tetraploid individuals. In these recombinant inbred lines, a single locus, which we call SENSITIVE TO DOSAGE IMBALANCE (SDI, exhibited segregation distortion in the tetraploid subpopulation only. Recent progress in quantitative genotyping now allows molecular karyotyping and genetic analysis of aneuploid populations. In this study, we investigated the causes of the ploidy-specific distortion at SDI. Allele frequency was distorted in the aneuploid swarms produced by the triploid hybrid. We developed a simple quantitative measure for aneuploidy lethality and using this measure demonstrated that distortion was greatest in the aneuploids facing the strongest viability selection. When triploids were crossed to euploids, the progeny, which lack severe aneuploids, exhibited no distortion at SDI. Genetic characterization of SDI in the aneuploid swarm identified a mechanism governing aneuploid survival, perhaps by buffering the effects of dosage imbalance. As such, SDI could increase the likelihood of retaining genomic rearrangements such as segmental duplications. Additionally, in species where triploids are fertile, aneuploid survival would facilitate gene flow between diploid and tetraploid populations via a triploid bridge and prevent polyploid speciation. Our results demonstrate that positional cloning of loci affecting traits in populations containing ploidy and

  16. 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.

  17. A Gain-of-Function Mutation in IAA7/AXR2 Confers Late Flowering under Short-day Light in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Yan-Xia Mai; Long Wang; Hong-Quan Yang

    2011-01-01

    Floral initiation is a major step in the life cycle of plants, which is influenced by photoperiod, temperature,and phytohormones, such as gibberellins (GAs). It is known that GAs promote floral initiation under short-day light conditions (SDs) by regulating the floral meristem-identity gene LEAFY (LFY) and the flowering-time gene SUPPRESSOR OF OVEREXPRESSlON OF CO 1 (SOC1). We have defined the role of the auxin signaling component INDOLE-3-ACETIC ACID 7 (IAA7)/AUXIN RESISTANT 2 (AXR2) in the regulation of flowering time in Arabidopsis thaliana. We demonstrate that the gain-of-function mutant of IAA7/AXR2, axr2-1, flowers late under SDs. The exogenous application of GAs rescued the late flowering phenotype of axr2-1 plants. The expression of the GA20 oxidase (GA20ox) genes, GA20ox1 and GA20ox2,was reduced in axr2-1 plants, and the levels of both LFY and SOC1 transcripts were reduced in axr2-1 mutants under SDs. Furthermore, the overexpression of SOC1 or LFY in axr2-1 mutants rescued the late flowering phenotype under SDs. Our results suggest that IAA7/AXR2 might act to inhibit the timing of floral transition under SDs, at least in part, by negatively regulating the expressions of the GA20ox1 and GA20ox2 genes.

  18. 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.

  19. Arabidopsis CDS blastp result: AK243512 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK243512 J100075C18 At4g16280.3 68417.m02471 flowering time ... control protein / FCA gamma (FCA) id ... entical to SP|O04425 Flowering time ... control protein FCA {Arabidopsis thaliana}; four a ...

  20. Arabidopsis CDS blastp result: AK243512 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK243512 J100075C18 At4g16280.2 68417.m02470 flowering time ... control protein / FCA gamma (FCA) id ... entical to SP|O04425 Flowering time ... control protein FCA {Arabidopsis thaliana}; four a ...

  1. Ectopic expression of a hyacinth AGL6 homolog caused earlier flowering and homeotic conversion in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    MADS-box genes are involved in floral organ development. Here we report that an AGL6(Agamous-like 6)-like MADS-box gene, HoAGL6, was isolated from Hyacinthus orientalis L. Expression pattern analysis demonstrated that HoAGL6 transcript was detected in inflorescence buds, tepals, carpels and ovules, but not in stamina, leaves or scales. Transgenic Arabidopsis plants ectopically expressing HoAGL6 exhibited novel phenotypes of significantly reduced plant size, extremely early flowering, and losing inflorescence indeterminacy. In addition, wide homeotic conversion of sepals, petals, and leaves into carpel-like or ovary structures, and disappearance or number reduction of stamens in 35S::HoAGL6 Arabidopsis plants were also observed. RT-PCR analysis indicated that the expressions of flowering time gene SOC1 and flower meristem identity gene LFY were significantly up-regulated in 35S::HoAGL6 transgenic Arabidopsis plants, and the expression levels of floral organ identity genes AG and SEP1 in leaves were also elevated. These results indicated that HoAGL6 was involved in the regulation of flower transition and flower organ formation.

  2. Profilin Plays a Role in Cell Elongation, Cell Shape Maintenance, and Flowering in Arabidopsis

    DEFF Research Database (Denmark)

    Ramachandran, S.; Christensen, Hans Erik Mølager; Ishimaru, Y.;

    2000-01-01

    Profilin (PFN) is an ubiquitous, low-M-r, actin-binding protein involved in the organization of the cytoskeleton of eukaryotes including higher plants. PFNs are encoded by a multigene family in Arabidopsis. We have analyzed in vivo functions of Arabidopsis PFN by generating transgenic plants...... carrying a 35S-PFN-1 or 35S-antisense PFN-1 transgene. Etiolated seedlings underexpressing PFN (PFN-U) displayed an overall dwarf phenotype with short hypocotyls whose lengths were 20% to 25% that of wild type (WT) at low temperatures. Light-grown PFN-U plants were smaller in stature and flowered early...... expressed in the vascular bundles of cotyledons and leaves. Our results show that Arabidopsis PFNs play a role in cell elongation, cell shape maintenance, polarized growth of root hair, and unexpectedly, in determination of flowering time....

  3. Gravity regulated genes in Arabidopsis thaliana (GENARA experiment)

    Science.gov (United States)

    Boucheron-Dubuisson, Elodie; Carnero-D&íaz, Eugénie; Medina, Francisco Javier; Gasset, Gilbert; Pereda-Loth, Veronica; Graziana, Annick; Mazars, Christian; Le Disquet, Isabelle; Eche, Brigitte; Grat, Sabine; Gauquelin-Koch, Guillemette

    2012-07-01

    In higher plants, post-embryonic development is possible through the expression of a set of genes constituting the morphogenetic program that contribute to the production of tissues and organs during the whole plant life cycle. Plant development is mainly controlled by internal factors such as phytohormones, as well as by environmental factors, among which gravity plays a key role (gravi-morphogenetic program). The GENARA space experiment has been designed with the goal of contributing to a better understanding of this gravi-morphogenetic program through the identification and characterization of some gravity regulated proteins (GR proteins) by using quantitative proteomic methods, and through the study of the impact of plant hormones on the expression of this program. Among plant hormones, auxin is the major regulator of organogenesis. In fact, it affects numerous plant developmental processes, e.g. cell division and elongation, autumnal loss of leaves, and the formation of buds, roots, flowers and fruits. Furthermore, it also plays a key role in the mechanisms of different tropisms (including gravitropism) that modulate fundamental features of plant growth. The expression of significant genes involved in auxin transport and in auxin signal perception in root cells is being studied in space-grown seedlings and compared with the corresponding ground controls. This experiment was scheduled to be performed in The European Modular Cultivation System (EMCS), a new facility for plant cultivation and Plant Molecular Biology studies, at ISS. However only one aspect of this experiment was flown and concerns the qualitative and quantitative changes in membrane proteins supposed to be mainly associated with cell signaling and has been called GENARA A. The second part dealing with the function of auxin in the gravi-morphogenetic program and the alterations induced by microgravity will be studied through mutants affected on biosynthesis, transport or perception of auxin in a

  4. Floral Induction in Arabidopsis by FLOWERING LOCUS T Requires Direct Repression of BLADE-ON-PETIOLE Genes by the Homeodomain Protein PENNYWISE.

    Science.gov (United States)

    Andrés, Fernando; Romera-Branchat, Maida; Martínez-Gallegos, Rafael; Patel, Vipul; Schneeberger, Korbinian; Jang, Seonghoe; Altmüller, Janine; Nürnberg, Peter; Coupland, George

    2015-11-01

    Flowers form on the flanks of the shoot apical meristem (SAM) in response to environmental and endogenous cues. In Arabidopsis (Arabidopsis thaliana), the photoperiodic pathway acts through FLOWERING LOCUS T (FT) to promote floral induction in response to day length. A complex between FT and the basic leucine-zipper transcription factor FD is proposed to form in the SAM, leading to activation of APETALA1 and LEAFY and thereby promoting floral meristem identity. We identified mutations that suppress FT function and recovered a new allele of the homeodomain transcription factor PENNYWISE (PNY). Genetic and molecular analyses showed that ectopic expression of BLADE-ON-PETIOLE1 (BOP1) and BOP2, which encode transcriptional coactivators, in the SAM during vegetative development, confers the late flowering of pny mutants. In wild-type plants, BOP1 and BOP2 are expressed in lateral organs close to boundaries of the SAM, whereas in pny mutants, their expression occurs in the SAM. This ectopic expression lowers FD mRNA levels, reducing responsiveness to FT and impairing activation of APETALA1 and LEAFY. We show that PNY binds to the promoters of BOP1 and BOP2, repressing their transcription. These results demonstrate a direct role for PNY in defining the spatial expression patterns of boundary genes and the significance of this process for floral induction by FT. PMID:26417007

  5. 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.

  6. DNA fingerprinting and new tools for fine-scale discrimination of Arabidopsis thaliana accessions.

    Science.gov (United States)

    Simon, Matthieu; Simon, Adeline; Martins, Fréderic; Botran, Lucy; Tisné, Sébastien; Granier, Fabienne; Loudet, Olivier; Camilleri, Christine

    2012-03-01

    One of the main strengths of Arabidopsis thaliana as a model species is the impressive number of public resources available to the scientific community. Exploring species genetic diversity--and therefore adaptation--relies on collections of individuals from natural populations taken from diverse environments. Nevertheless, due to a few mislabeling events or genotype mixtures, some variants available in stock centers have been misidentified, causing inconsistencies and limiting the potential of genetic analyses. To improve the identification of natural accessions, we genotyped 1311 seed stocks from our Versailles Arabidopsis Stock Center and from other collections to determine their molecular profiles at 341 single nucleotide polymorphism markers. These profiles were used to compare genotypes at both the intra- and inter-accession levels. We confirmed previously described inconsistencies and revealed new ones, and suggest likely identities for accessions whose lineage had been lost. We also developed two new tools: a minimal fingerprint computation to quickly verify the identity of an accession, and an optimized marker set to assist in the identification of unknown or mixed accessions. These tools are available on a dedicated web interface called ANATool (https://www.versailles.inra.fr/ijpb/crb/anatool) that provides a simple and efficient means to verify or determine the identity of A. thaliana accessions in any laboratory, without the need for any specific or expensive technology. PMID:22077701

  7. Spatial relationship between chromosomal domains in diploid and autotetraploid Arabidopsis thaliana nuclei.

    Science.gov (United States)

    Sas-Nowosielska, H; Bernas, T

    2016-04-25

    Polyploids constitute more than 80% of angiosperm plant species. Their DNA content is often further increased by endoreplication, which occurs as a part of cell differentiation. Here, we explore the relationship between 3D chromatin architecture, number of genome copies and their origin in the model plant, Arabidopsis thaliana. Spatial proximity between pericentromeric, interstitial and subtelomeric domains of chromosomes 1 and 4 was quantified over a range of distances. The results indicate that average nuclear volume as well as chromatin density increase with the genome copy number. Similar dependence is observed when association of homologous chromosomes (in 2C/ endopolyploid nuclei) and sister chromatid separation (in endopolyploid nuclei) is studied. Moreover, clusters of chromosomal domains are detectable at the spatial scale above microscopy resolution. Subtelomeric, interstitial and pericentromeric chromosomal domains are affected to different extent by these processes, which are modulated by endopolyploidy. This factor influences fusion of heterochromatin as well. Nonetheless, local chromatin architecture of Arabidopsis thaliana depends mainly on endopolyploidy level, and to lesser extend on polyploidy. PMID:27310308

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

    Directory of Open Access Journals (Sweden)

    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.

  9. Natural variation of root exudates in Arabidopsis thaliana-linking metabolomic and genomic data.

    Science.gov (United States)

    Mönchgesang, Susann; Strehmel, Nadine; Schmidt, Stephan; Westphal, Lore; Taruttis, Franziska; Müller, Erik; Herklotz, Siska; Neumann, Steffen; Scheel, Dierk

    2016-01-01

    Many metabolomics studies focus on aboveground parts of the plant, while metabolism within roots and the chemical composition of the rhizosphere, as influenced by exudation, are not deeply investigated. In this study, we analysed exudate metabolic patterns of Arabidopsis thaliana and their variation in genetically diverse accessions. For this project, we used the 19 parental accessions of the Arabidopsis MAGIC collection. Plants were grown in a hydroponic system, their exudates were harvested before bolting and subjected to UPLC/ESI-QTOF-MS analysis. Metabolite profiles were analysed together with the genome sequence information. Our study uncovered distinct metabolite profiles for root exudates of the 19 accessions. Hierarchical clustering revealed similarities in the exudate metabolite profiles, which were partly reflected by the genetic distances. An association of metabolite absence with nonsense mutations was detected for the biosynthetic pathways of an indolic glucosinolate hydrolysis product, a hydroxycinnamic acid amine and a flavonoid triglycoside. Consequently, a direct link between metabolic phenotype and genotype was detected without using segregating populations. Moreover, genomics can help to identify biosynthetic enzymes in metabolomics experiments. Our study elucidates the chemical composition of the rhizosphere and its natural variation in A. thaliana, which is important for the attraction and shaping of microbial communities. PMID:27363486

  10. Activity of Antioxidant Enzymes in Response to Cadmium in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    A. Saffar

    2009-01-01

    Full Text Available The effects of the heavy metal cadmium (Cd+2 on growth and activities of the antioxidant enzymes, catalase (CAT, peroxidase (POD and polyphenol oxidase (PPO have been investigated in Arabidopsis thaliana L. seedlings. The concentration of 50 and 100 μM CdCl2 was shown to strongly inhibit the growth of roots and lipid peroxidation. Lipid peroxidation of seedlings shoots rose with increasing concentrations of Cd+2 as indicated by malondialdehyde (MDA concentration. As Cd+2 concentration increased, catalase (CAT activity declined progressively, while peroxidase and polyphenol oxidase activity increased when compared to the untreated plants. Close correlations between increased MDA formation and decreased root growth as well as CAT activity suggests that lipid peroxidation might caused cell damage and death proposing that applied concentrations of Cd+2 could be toxic to cells. It was also noted that Cd+2-induced cell injury and lipid peroxidation correlated with increased peroxidase and polyphenol oxidase activities, two antioxidant enzymes involved in polyphenol peroxidation as lignification substrates. Together, the results suggest that in Arabidopsis thaliana reactive oxygen species (ROS could be induced by phytotoxic concentrations of Cd+2 leading to increased POD and PPO activities which play a crucial role in detoxification of elevated concentrations of Cd+2 possibly via lignifications and physical barrier formation.

  11. Defective RNA processing enhances RNA silencing and influences flowering of Arabidopsis

    OpenAIRE

    Herr, Alan J.; Molnàr, Attila; Jones, Alex; Baulcombe, David C.

    2006-01-01

    Many eukaryotic cells use RNA-directed silencing mechanisms to protect against viruses and transposons and to suppress endogenous gene expression at the posttranscriptional level. RNA silencing also is implicated in epigenetic mechanisms affecting chromosome structure and transcriptional gene silencing. Here, we describe enhanced silencing phenotype (esp) mutants in Arabidopsis thaliana that reveal how proteins associated with RNA processing and 3′ end formation can influence RNA silencing. T...

  12. Bacterial communities associated with the leaves and the roots of Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Natacha Bodenhausen

    Full Text Available Diverse communities of bacteria inhabit plant leaves and roots and those bacteria play a crucial role for plant health and growth. Arabidopsis thaliana is an important model to study plant pathogen interactions, but little is known about its associated bacterial community under natural conditions. We used 454 pyrosequencing to characterize the bacterial communities associated with the roots and the leaves of wild A. thaliana collected at 4 sites; we further compared communities on the outside of the plants with communities in the endophytic compartments. We found that the most heavily sequenced bacteria in A. thaliana associated community are related to culturable species. Proteobacteria, Actinobacteria, and Bacteroidetes are the most abundant phyla in both leaf and root samples. At the genus level, sequences of Massilia and Flavobacterium are prevalent in both samples. Organ (leaf vs root and habitat (epiphytes vs endophytes structure the community. In the roots, richness is higher in the epiphytic communities compared to the endophytic compartment (P = 0.024, while the reverse is true for the leaves (P = 0.032. Interestingly, leaf and root endophytic compartments do not differ in richness, diversity and evenness, while they differ in community composition (P = 0.001. The results show that although the communities associated with leaves and roots share many bacterial species, the associated communities differ in structure.

  13. A GC/MS method for determination of succinylacetone in Arabidopsis thaliana.

    Science.gov (United States)

    Zhou, Lizi; Yang, Zhaoguang; Zhi, Tiantian; Zhou, Zhou; Wang, Xiaochen; Ren, Chunmei; Qiu, Bo

    2016-07-01

    Succinylacetone was known to be a toxic metabolite of tyrosine in human and animals caused by blockage of the final step in tyrosine degradation pathway, but its existence in plant was unclear though the metabolic disturbance of tyrosine was also found in plant. A GC-MS method for determination of succinylacetone in Arabidopsis thaliana was developed for the first time. Both oximation and silylation were applied in the derivation procedure, and a low-temperature condition before completion of oximation was found to be necessary to obtain good linearity of the calibration curve due to the thermolability of succinylacetone. The specific chromatogram pattern formed by the four isomers of succinylacetone derivatives provided a helpful feature for its identification. The detection limit of the proposed method was 0.25 ppm in A. thaliana. The recoveries were between 95.4 and 109.3 % with the coefficient of variation ranging from 4.36 to 7.81 % for intra-day assays and 6.47 to 8.52 % for inter-day assays. Application to wild-type and the short-day sensitive cell death 1 mutant of A. thaliana represented an obvious correlation between the measured amount of succinylacetone and wilting symptom, suggesting the proposed method could be a powerful tool in further study on toxicology of succinylacetone and tyrosine catabolism in plants. PMID:27086013

  14. 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.

  15. Unique features of the m6A methylome in Arabidopsis thaliana.

    Science.gov (United States)

    Luo, Guan-Zheng; MacQueen, Alice; Zheng, Guanqun; Duan, Hongchao; Dore, Louis C; Lu, Zhike; Liu, Jun; Chen, Kai; Jia, Guifang; Bergelson, Joy; He, Chuan

    2014-01-01

    Recent discoveries of reversible N(6)-methyladenosine (m(6)A) methylation on messenger RNA (mRNA) and mapping of m(6)A methylomes in mammals and yeast have revealed potential regulatory functions of this RNA modification. In plants, defects in m(6)A methyltransferase cause an embryo-lethal phenotype, suggesting a critical role of m(6)A in plant development. Here, we profile m(6)A transcriptome-wide in two accessions of Arabidopsis thaliana and reveal that m(6)A is a highly conserved modification of mRNA in plants. Distinct from mammals, m(6)A in A. thaliana is enriched not only around the stop codon and within 3'-untranslated regions, but also around the start codon. Gene ontology analysis indicates that the unique distribution pattern of m(6)A in A. thaliana is associated with plant-specific pathways involving the chloroplast. We also discover a positive correlation between m(6)A deposition and mRNA abundance, suggesting a regulatory role of m(6)A in plant gene expression. PMID:25430002

  16. Burkholderia phytofirmans PsJN reduces impact of freezing temperatures on photosynthesis in Arabidopsis thaliana

    Science.gov (United States)

    Su, Fan; Jacquard, Cédric; Villaume, Sandra; Michel, Jean; Rabenoelina, Fanja; Clément, Christophe; Barka, Essaid A.; Dhondt-Cordelier, Sandrine; Vaillant-Gaveau, Nathalie

    2015-01-01

    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 mesophyll. Impact 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. thaliana

  17. 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

  18. Identification and map location of TTR1, a single locus in Arabidopsis thaliana that confers tolerance to tobacco ringspot nepovirus.

    Science.gov (United States)

    Lee, J M; Hartman, G L; Domier, L L; Bent, A F

    1996-11-01

    The interaction between Arabidopsis and the nepovirus tobacco ringspot virus (TRSV) was characterized. Of 97 Arabidopsis lines tested, all were susceptible when inoculated with TRSV grape strain. Even though there was systemic spread of the virs, there was a large degree of variation in symptoms as the most sensitive lines died 10 days after inoculation, while the most tolerant lines either were symptomless or developed only mild symptoms. Four lines were selected for further study based on their differential reactions to TRSV. Infected plants of line Col-0 and Col-0 gl1 flowered and produced seeds like noninfected plants, while those of lines Estland and H55 died before producing seeds. Symptoms appeared on sensitive plants approximately 5 to 6 days after inoculation. Serological studies indicated that in mechanically inoculated seedlings, the virus, as measured by coat protein accumulation, developed at essentially the same rates and to the same levels in each of the four lines, demonstrating that differences in symptom development were not due to a suppression of virus accumulation. Two additional TRSV strains gave similar results when inoculated on the four lines. Genetic studies with these four Arabidopsis lines revealed segregation of a single incompletely dominant locus controlling tolerance to TRSV grape strain. We have designated this locus TTR1. By using SSLP and CAPS markers, TTR1 was mapped to chromosome V near the nga129 marker. Seed transmission frequency of TRSV for Col-0 and Col-0 gl1 was over 95% and their progeny from crosses all had seed transmission frequencies of over 83%, which made it possible to evaluate the segregation of TTR1 in F2 progeny from infected F1 plants without inoculating F2 plants. Seed transmission of TRSV will be further exploited to streamline selection of individuals for fine mapping the TTR1 gene. The identification of tolerant and sensitive interactions between TRSV and A. thaliana lines provides a model system for

  19. 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.

  20. 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

  1. X-Ray- and fast neutron induced mutations in Arabidopsis thaliana, and the effect of dithiothreitol upon the mutant spectrum

    NARCIS (Netherlands)

    Dellaert, L.M.W.

    1980-01-01

    The genetic effects of X-ray and fast neutron seed-irradiation of Arabidopsis thaliana (L.) Heynh., and the influence of a pre-irradiation treatment with the radio-protector dithiothreitol (DTT), are the main subjects of this thesis.Chapters I and II deal with the effects of radiation - with or with

  2. Probing cytokinin homeostasis in Arabidopsis thaliana by constitutively overexpressing two forms of the maize cytokinin oxidase/dehydrogenase 1 gene

    Czech Academy of Sciences Publication Activity Database

    Kopečný, D.; Tarkowski, Petr; Majira, M.; Bouchez-Mahiout, I.; Nogué, F.; Laurière, M.; Sandberg, G.; Laloue, M.; Houba-Hérin, N.

    2006-01-01

    Roč. 171, č. 1 (2006), s. 114-122. ISSN 0168-9452 Institutional research plan: CEZ:AV0Z50380511 Keywords : Arabidopsis thaliana * Cytokinin oxidase/dehydrogenase * Homeostasis Subject RIV: CE - Biochemistry Impact factor: 1.631, year: 2006

  3. Overexpression of AtAP1M3 regulates flowering time and floral development in Arabidopsis and effects key flowering-related genes in poplar.

    Science.gov (United States)

    Chen, Zhong; Ye, Meixia; Su, Xiaoxing; Liao, Weihua; Ma, Huandi; Gao, Kai; Lei, Bingqi; An, Xinmin

    2015-08-01

    APETALA1 plays a crucial role in the transition from vegetative to reproductive phase and in floral development. In this study, to determine the effect of AP1 expression on flowering time and floral organ development, transgenic Arabidopsis and poplar overexpressing of AtAP1M3 (Arabidopsis AP1 mutant by dominant negative mutation) were generated. Transgenic Arabidopsis with e35Spro::AtAP1M3 displayed phenotypes with delayed-flowering compared to wild-type and flowers with abnormal sepals, petals and stamens. In addition, transgenic Arabidopsis plants exhibited reduced growth vigor compared to the wild-type plants. Ectopic expression of AtAP1M3 in poplar resulted in up- or down-regulation of some endogenous key flowering-related genes, including floral meristems identity gene LFY, B-class floral organ identity genes AP3 and PI, flowering pathway integrator FT1 and flower repressors TFL1 and SVP. These results suggest that AtAP1M3 regulates flowering time and floral development in plants. PMID:25820621

  4. Functional conservation of rice OsNF-YB/YC and Arabidopsis AtNF-YB/YC proteins in the regulation of flowering time

    KAUST Repository

    Hwang, Yoon-Hyung

    2016-01-11

    Plant NUCLEAR FACTOR Y (NF-Y) transcription factors play important roles in plant development and abiotic stress. In Arabidopsis thaliana, two NF-YB (AtNF-YB2 and AtNF-YB3) and five NF-YC (AtNF-YC1, AtNF-YC2, AtNF-YC3, AtNF-YC4, and AtNF-YC9) genes regulate photoperiodic flowering by interacting with other AtNF-Y subunit proteins. Three rice NF-YB (OsNF-YB8, OsNF-YB10, and OsNF-YB11) and five rice OsNF-YC (OsNF-YC1, OsNF-YC2, OsNF-YC4, OsNF-YC6, and OsNF-YC7) genes are clustered with two AtNF-YB and five AtNF-YC genes, respectively. To investigate the functional conservation of these NF-YB and NF-YC genes in rice and Arabidopsis, we analyzed the flowering phenotypes of transgenic plants overexpressing the respective OsNF-YB and OsNF-YC genes in Arabidopsis mutants. Overexpression of OsNF-YB8/10/11 and OsNF-YC2 complemented the late flowering phenotype of Arabidopsis nf-yb2 nf-yb3 and nf-yc3 nf-yc4 nf-yc9 mutants, respectively. The rescued phenotype of 35S::OsNF-YC2 nf-yc3 nf-yc4 nf-yc9 plants was attributed to the upregulation of FLOWERING LOCUS T (FT) and SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (SOC1). In vitro and in planta protein–protein analyses revealed that OsNF-YB8/10/11 and OsNF-YC1/2/4/6/7 interact with AtNF-YC3/4/9 and AtNF-YB2/3, respectively. Our data indicate that some OsNF-YB and OsNF-YC genes are functional equivalents of AtNF-YB2/3 and AtNF-YC3/4/9 genes, respectively, and suggest functional conservation of Arabidopsis and rice NF-Y genes in the control of flowering time.

  5. 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. PMID:22316300

  6. AtMYB12 regulates flavonoids accumulation and abiotic stress tolerance in transgenic Arabidopsis thaliana.

    Science.gov (United States)

    Wang, Feibing; Kong, Weili; Wong, Gary; Fu, Lifeng; Peng, Rihe; Li, Zhenjun; Yao, Quanhong

    2016-08-01

    In plants, transcriptional regulation is the most important tool for modulating flavonoid biosynthesis. The AtMYB12 gene from Arabidopsis thaliana has been shown to regulate the expression of key enzyme genes involved in flavonoid biosynthesis, leading to the increased accumulation of flavonoids. In this study, the codon-optimized AtMYB12 gene was chemically synthesized. Subcellular localization analysis in onion epidermal cells indicated that AtMYB12 was localized to the nucleus. Its overexpression significantly increased accumulation of flavonoids and enhanced salt and drought tolerance in transgenic Arabidopsis plants. Real-time quantitative PCR (qRT-PCR) analysis showed that overexpression of AtMYB12 resulted in the up-regulation of genes involved in flavonoid biosynthesis, abscisic acid (ABA) biosynthesis, proline biosynthesis, stress responses and ROS scavenging under salt and drought stresses. Further analyses under salt and drought stresses showed significant increases of ABA, proline content, superoxide dismutase (SOD) and peroxidase (POD) activities, as well as significant reduction of H2O2 and malonaldehyde (MDA) content. The results demonstrate the explicit role of AtMYB12 in conferring salt and drought tolerance by increasing the levels of flavonoids and ABA in transgenic Arabidopsis. The AtMYB12 gene has the potential to be used to enhance tolerance to abiotic stresses in plants. PMID:27033553

  7. Analysis of fast neutron-generated mutants at the Arabidopsis thaliana HY4 locus

    International Nuclear Information System (INIS)

    Ionizing radiation is expected to produce mutants with deletions or other chromosomal rearrangements. These mutants are useful for a variety of purposes, such as creating null alleles and cloning genes whose existence is known only from their mutant phenotype; however, only a few mutations generated by ionizing radiation have been characterized at the molecular level in Arabidopsis thaliana. Twenty fast neutron-generated alleles of the Arabidopsis HY4 locus, which encodes a blue light receptor, CRY1, were isolated and characterized. Nine of the mutant alleles displayed normal genetic behavior. The other 11 mutant alleles were poorly transmitted through the male gametophyte and were lethal in homozygous plants. Southern blot analysis demonstrated that alleles of the first group generally contain small or moderate-sized deletions at HY4, while alleles of the second group contain large deletions at this locus. These results demonstrate that fast neutrons can produce a range of deletions at a single locus in Arabidopsis. Many of these deletions would be suitable for cloning by genomic subtraction or representational difference analysis. The results also suggest the presence of an essential locus adjacent to HY4. (author)

  8. Requirement of KNAT1/BP for the Development of Abscission Zones in Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    Xiao-Qun Wang; Wei-Hui Xu; Li-Geng Ma; Zhi-Ming Fu; Xing-Wang Deng; Jia-Yang Li; Yong-Hong Wang

    2006-01-01

    The KNAT1 gene is a member of the Class Ⅰ KNOXhomeobox gene family and is thought to play an important role in meristem development and leaf morphogenesis. Recent studies have demonstrated that KNAT1/BP regulates the architecture of the inflorescence by affecting pedicle development in Arabidopsis thaliana.Herein, we report the characterization of an Arabidopsis T-DNA insertion mutant that shares considerable phenotypic similarity to the previously identified mutant brevipedicle (bp). Molecular and genetic analyses showed that the mutant is allelic to bp and that the T-DNA is located within the first helix of the KNAT1homeodomain (HD). Although the mutation causes a typical abnormality of short pedicles, propendent siliques,and semidwarfism, no obvious defects are observed in the vegetative stage. A study on cell morphology showed that asymmetrical division and inhibition of cell elongation contribute to the downward-pointing and shorter pedicle phenotype. Loss of KNAT/BPfunction results in the abnormal development of abscission zones. Microarray analysis of gene expression profiling suggests that KNAT1/BP may regulate abscission zone development through hormone signaling and hormone metabolism in Arabidopsis.

  9. 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.

  10. 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. PMID:26153342

  11. Defence responses of Arabidopsis thaliana to infection by Pseudomonas syringae are regulated by the circadian clock.

    Directory of Open Access Journals (Sweden)

    Vaibhav Bhardwaj

    Full Text Available 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.

  12. 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.

  13. 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.

  14. Putative sugarcane FT/TFL1 genes delay flowering time and alter reproductive architecture in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Carla P. Coelho

    2014-05-01

    Full Text Available Agriculturally important grasses such as rice, maize and sugarcane are evolutionarily distant from Arabidopsis, yet some components of the floral induction process are highly conserved. Flowering in sugarcane is an important factor that negatively affects cane yield and reduces sugar/ethanol production from this important perennial bioenergy crop. Comparative studies have facilitated the identification and characterization of putative orthologs of key flowering time genes in sugarcane, a complex polyploid plant whose genome has yet to be sequenced completely. Using this approach we identified phosphatidylethanolamine-binding protein (PEBP gene family members in sugarcane that are similar to the archetypical FT and TFL1 genes of Arabidopsis that play an essential role in controlling the transition from vegetative to reproductive growth. Expression analysis of ScTFL1, which falls into the TFL1-clade of floral repressors, showed transcripts in developing leaves surrounding the shoot apex but not at the apex itself. ScFT1 was detected in immature leaves and apical regions of vegetatively growing plants and, after the floral transition, expression also occurred in mature leaves. Ectopic over-expression of ScTFL1 in Arabidopsis caused delayed flowering in Arabidopsis, as might be expected for a gene related to TFL1. In addition, lines with the latest flowering phenotype exhibited aerial rosette formation. Unexpectedly, over-expression of ScFT1, which has greatest similarity to the florigen-encoding FT, also caused a delay in flowering. This preliminary analysis of divergent sugarcane FT and TFL1 gene family members from Saccharum spp. suggests that their expression patterns and roles in the floral transition has diverged from the predicted role of similar PEBP family members.

  15. Overexpression of AtBMI1C, a polycomb group protein gene, accelerates flowering in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Wei Li

    Full Text Available Polycomb group protein (PcG-mediated gene silencing is emerging as an essential developmental regulatory mechanism in eukaryotic organisms. PcGs inactivate or maintain the silenced state of their target chromatin by forming complexes, including Polycomb Repressive Complex 1 (PRC1 and 2 (PRC2. Three PRC2 complexes have been identified and characterized in Arabidopsis; of these, the EMF and VRN complexes suppress flowering by catalyzing the trimethylation of lysine 27 on histone H3 of FLOWER LOCUS T (FT and FLOWER LOCUS C (FLC. However, little is known about the role of PRC1 in regulating the floral transition, although AtRING1A, AtRING1B, AtBMI1A, and AtBMI1B are believed to regulate shoot apical meristem and embryonic development as components of PRC1. Moreover, among the five RING finger PcGs in the Arabidopsis genome, four have been characterized. Here, we report that the fifth, AtBMI1C, is a novel, ubiquitously expressed nuclear PcG protein and part of PRC1, which is evolutionarily conserved with Psc and BMI1. Overexpression of AtBMI1C caused increased H2A monoubiquitination and flowering defects in Arabidopsis. Both the suppression of FLC and activation of FT were observed in AtBMI1C-overexpressing lines, resulting in early flowering. No change in the H3K27me3 level in FLC chromatin was detected in an AtBMI1C-overexpressing line. Our results suggest that AtBMI1C participates in flowering time control by regulating the expression of FLC; moreover, the repression of FLC by AtBMI1C is not due to the activity of PRC2. Instead, it is likely the result of PRC1 activity, into which AtBMI1C is integrated.

  16. Transcriptional profiling of pea ABR17 mediated changes in gene expression in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Deyholos Michael K

    2008-09-01

    Full Text Available Abstract Background Pathogenesis-related proteins belonging to group 10 (PR10 are elevated in response to biotic and abiotic stresses in plants. Previously, we have shown a drastic salinity-induced increase in the levels of ABR17, a member of the PR10 family, in pea. Furthermore, we have also demonstrated that the constitutive expression of pea ABR17 cDNA in Arabidopsis thaliana and Brassica napus enhances their germination and early seedling growth under stress. Although it has been reported that several members of the PR10 family including ABR17 possess RNase activity, the exact mechanism by which the aforementioned characteristics are conferred by ABR17 is unknown at this time. We hypothesized that a study of differences in transcriptome between wild type (WT and ABR17 transgenic A. thaliana may shed light on this process. Results The molecular changes brought about by the expression of pea ABR17 cDNA in A. thaliana in the presence or absence of salt stress were investigated using microarrays consisting of 70-mer oligonucleotide probes representing 23,686 Arabidopsis genes. Statistical analysis identified number of genes which were over represented among up- or down-regulated transcripts in the transgenic line. Our results highlight the important roles of many abscisic acid (ABA and cytokinin (CK responsive genes in ABR17 transgenic lines. Although the transcriptional changes followed a general salt response theme in both WT and transgenic seedlings under salt stress, many genes exhibited differential expression patterns when the transgenic and WT lines were compared. These genes include plant defensins, heat shock proteins, other defense related genes, and several transcriptional factors. Our microarray results for selected genes were validated using quantitative real-time PCR. Conclusion Transcriptional analysis in ABR17 transgenic Arabidopsis plants, both under normal and saline conditions, revealed significant changes in abundance of

  17. 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. 

  18. Comparison of rhizosphere bacterial communities in Arabidopsis thaliana mutants for systemic acquired resistance.

    Science.gov (United States)

    Hein, John W; Wolfe, Gordon V; Blee, Kristopher A

    2008-02-01

    Systemic acquired resistance (SAR) is an inducible systemic plant defense against a broad spectrum of plant pathogens, with the potential to secrete antimicrobial compounds into the soil. However, its impact on rhizosphere bacteria is not known. In this study, we examined fingerprints of bacterial communities in the rhizosphere of the model plant Arabidopsis thaliana to determine the effect of SAR on bacterial community structure and diversity. We compared Arabidopsis mutants that are constitutive and non-inducible for SAR and verified SAR activation by measuring pathogenesis-related protein activity via a beta-glucoronidase (GUS) reporter construct driven by the beta-1-3 glucanase promoter. We used terminal restriction fragment length polymorphism (T-RFLP) analysis of MspI- and HaeIII-digested 16S rDNA to estimate bacterial rhizosphere community diversity, with Lactobacillus sp. added as internal controls. T-RFLP analysis showed a clear rhizosphere effect on community structure, and diversity analysis of both rhizosphere and bulk soil operational taxonomic units (as defined by terminal restriction fragments) using richness, Shannon-Weiner, and Simpson's diversity indices and evenness confirmed that the presence of Arabidopsis roots significantly altered bacterial communities. This effect of altered soil microbial community structure by plants was also seen upon multivariate cluster analysis of the terminal restriction fragments. We also found visible differences in the rhizosphere community fingerprints of different Arabidopsis SAR mutants; however, there was no clear decrease of rhizosphere diversity because of constitutive SAR expression. Our study suggests that SAR can alter rhizosphere bacterial communities, opening the door to further understanding and application of inducible plant defense as a driving force in structuring soil bacterial assemblages. PMID:17619212

  19. Cloning and expression of AtPLC6, a gene encoding a phosphatidylinositol-specific phospholipase C in Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    XU Xiaojing; CAO Zhixiang; LIU Guoqin; Madan K. Bhattacharrya; REN Dongtao

    2004-01-01

    A full-length eDNA clone corresponding to a putative phosphatidylinositol-specific phospholipase C (PIPLC) was isolated from Arabidopsis thaliana by screening a cDNA library and using RT-PCR strategy. The cDNA, designated AtPLC6, encodes a putative polypeptide of 578 amino acid residues with a calculated molecular mass of 66251.84 D and a pI of 7.24. The sequence analysis indicates that the polypeptide contains X, Y, EF-hand and C2 domains. The overall structure of putative AtPLC6 protein, like other plant PI-PLCs, is most similar to that of mammalian PLC& The recombinant AtPLC6 protein expressed in E. coli was able to hydrolyze phosphatidylinositol 4,5-biophosphate (PIP2) to generate inositol 1,4,5-trisphate (IP3) and 1,2-diacylglycerol (DAG). The protein hydrolyzes PIP2 in a Ca2+-dependent manner and the optimum concentration of Ca2+ is 10 μmol/L.These results suggested that AtPLC6 gene encodes a genuine PI-PLC. Northern blot analysis showed that the AtPLC6 gene is expressed at low level in all examined tissues, such as roots,stems, leaves, flowers, siliques and seedlings under normal growth conditions. The gene is strongly induced under low temperature and weakly induced under various stresses,such as ABA, high-salt stress and heat. These results suggested that AtPLC6 might be involved in the signal-transduction pathways of cold responses of the plants.

  20. 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

    2016-07-01

    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. PMID:26771455

  1. Seed coat mucilage cells of Arabidopsis thaliana as a model for plant cell wall research.

    Science.gov (United States)

    Arsovski, Andrej A; Haughn, George W; Western, Tamara L

    2010-07-01

    Plant cells are encased within a complex polysaccharide wall that strengthens the cell and has key roles in all aspects of plant cell growth, differentiation, and interaction with the environment. This dynamic structure is under continual modification during plant development, and its synthesis and modification require the activity of a myriad of enzymes. The mucilage secretory cells (MSCs) of the Arabidopsis thaliana seed coat provide a model for the discovery of novel genes involved in the synthesis, secretion and modification of cell wall components, particularly pectin. These cells synthesize copious amounts of pectinaceous mucilage during development and, upon hydration of the desiccated seed, the mucilage rapidly swells, bursts from the MSCs and surrounds the seed in a gelatinous capsule. Several genes affecting MSC differentiation, pectin synthesis, and mucilage release have been identified and additional genes involved in these and related processes including pectin secretion and the mechanical alteration of cell walls await to be discovered. PMID:20505351

  2. Ultrastructural study of maturing pollen in Arabidopsis thaliana (L. Heynh. (Brassicaceae

    Directory of Open Access Journals (Sweden)

    Krystyna Zając

    2014-02-01

    Full Text Available Ultrastructural changes in Arabidopsis thaliana pollen, between late microspore stage and mature pollen stage were described. When the generative cell was peeled off from the intine, it was of spherical shape and had all usual organelles with the exception of plastids. The cytoplasm transformation of the vegetative cell included an increase in the number of mitochondria and changes in the accumulation of starch and lipid bodies. The starch plastids were observed at the bicellular and early tricellular pollen stages and next starch was utilized during the maturation procces. The lipid bodies of the vegetative cell form a very regular sheath around the generative cell and then, around the sperm cells. Before anthesis the lipid bodies were dispersed within the whole vegetative cell cytoplasm.

  3. Changes in cell ultrastructure and morphology of Arabidopsis thaliana roots after coumarins treatment

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    Ewa Kupidłowska

    2014-02-01

    Full Text Available The ultrastructure and morphology of roots treated with coumarin and umbelliferone as well as the reversibility of the coumarins effects caused by exogenous GA, were studied in Arabidopsis thaliana. Both coumarins suppressed root elongation and appreciably stimulated radial expansion of epidermal and cortical cells in the upper part of the meristem and in the elongation zone. The gibberellic acid applied simultaneously with coumarins decreased their inhibitory effect on root elongation and reduced cells swelling.Microscopic observation showed intensive vacuolization of cells and abnormalities in the structure of the Golgi stacks and the nuclear envelope. The detection of active acid phosphatase in the cytosol of swollen cells indicated increased membrane permeability. Significant abnormalities of newly formed cell walls, e.g. the discontinuity of cellulose layer, uncorrect position of walls and the lack of their bonds with the mother cell wall suggest that coumarins affected the cytoskeleton.

  4. A Method for Preparing Spaceflight RNAlater-Fixed Arabidopsis thaliana (Brassicaceae Tissue for Scanning Electron Microscopy

    Directory of Open Access Journals (Sweden)

    Eric R. Schultz

    2013-07-01

    Full Text Available Premise of the study: In spaceflight experiments, tissues for morphologic study are fixed in 3% glutaraldehyde, while tissues for molecular study are fixed in RNAlater; thus, an experiment containing both study components requires multiple fixation strategies. The possibility of using RNAlater-fixed materials for standard SEM-based morphometric investigation was explored to expand the library of tissues available for analysis and maximize usage of samples returned from spaceflight, but these technologies have wide application to any situation where recovery of biological resources is limited. Methods and Results: RNAlater-fixed samples were desalinated in distilled water, dehydrated through graded methanol, plunged into liquid ethane, and transferred to cryovials for freeze-substitution. Sample tissues were critical point dried, mounted, sputter-coated, and imaged. Conclusions: The protocol resulted in acceptable SEM images from RNAlater-fixed Arabidopsis thaliana tissue. The majority of the tissues remained intact, including general morphology and finer details such as root hairs and trichomes.

  5. The Arabidopsis thaliana ortholog of a purported maize cholinesterase gene encodes a GDSL-lipase.

    Science.gov (United States)

    Muralidharan, Mrinalini; Buss, Kristina; Larrimore, Katherine E; Segerson, Nicholas A; Kannan, Latha; Mor, Tsafrir S

    2013-04-01

    Acetylcholinesterase is an enzyme that is intimately associated with regulation of synaptic transmission in the cholinergic nervous system and in neuromuscular junctions of animals. However the presence of cholinesterase activity has been described also in non-metazoan organisms such as slime molds, fungi and plants. More recently, a gene purportedly encoding for acetylcholinesterase was cloned from maize. We have cloned the Arabidopsis thaliana homolog of the Zea mays gene, At3g26430, and studied its biochemical properties. Our results indicate that the protein encoded by the gene exhibited lipase activity with preference to long chain substrates but did not hydrolyze choline esters. The At3g26430 protein belongs to the SGNH clan of serine hydrolases, and more specifically to the GDS(L) lipase family. PMID:23430565

  6. 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.

  7. A Mutation Causing Imidazolinone Resistance Maps to the Csr1 Locus of Arabidopsis thaliana.

    Science.gov (United States)

    Haughn, G W; Somerville, C R

    1990-04-01

    A mutant of Arabidopsis thaliana, two hundred times more resistant to the imidazolinone herbicide imazapyr than wild-type plants, was isolated by direct selection of seedlings from a mutagenized population. Genetic analysis showed that resistance is due to a single dominant nuclear mutation that could not be separated by recombination from a mutation in the CSR1 gene encoding acetohydroxy acid synthase. Acetohydroxy acid synthase activity in extracts isolated from the mutant was 1000-fold more resistant to inhibition by imazapyr than that of the wild type. The resistant enzyme activity cosegregated with whole plant resistance. These data strongly suggest that the mutation is an allele of CSR1 encoding an imazapyr-resistant AHAS. PMID:16667374

  8. 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.

  9. Mitochondrial outer membrane forms bridge between two mitochondria in Arabidopsis thaliana.

    Science.gov (United States)

    Yamashita, Akihiro; Fujimoto, Masaru; Katayama, Kenta; Tsutsumi, Nobuhiro; Arimura, Shin-Ichi

    2016-05-01

    Mitochondria are double-membrane organelles that move around and change their shapes dynamically. In plants, the dynamics of the outer membrane is not well understood. We recently demonstrated that mitochondria had tubular protrusions of the outer membrane with little or no matrix, called MOPs (mitochondrial outer-membrane protrusions; MOPs). Here we show that a MOP can form a bridge between two mitochondria in Arabidopsis thaliana. The bridge does not appear to involve the inner membranes. Live imaging revealed stretching of the MOP bridge, demonstrating the flexibility of the outer membrane. Mitochondria frequently undergo fission and fusion. These observations raise the possibility that MOPs bridges have a role in these processes. PMID:27031262

  10. A Direct Screening Procedure for Gravitropism Mutants in Arabidopsis thaliana (L.) Heynh. 1

    Science.gov (United States)

    Bullen, Bertha L.; Best, Thérèse R.; Gregg, Mary M.; Barsel, Sara-Ellen; Poff, Kenneth L.

    1990-01-01

    In order to isolate gravitropism mutants of Arabidopsis thaliana (L.) Heynh. var Estland for the genetic dissection of the gravitropism pathway, a direct screening procedure has been developed in which mutants are selected on the basis of their gravitropic response. Variability in hypocotyl curvature was dependent on the germination time of each seed stock, resulting in the incorrect identification of several lines as gravitropism mutants when a standard protocol for the potentiation of germination was used. When the protocol was adjusted to allow for differences in germination time, these lines were eliminated from the collection. Out of the 60,000 M2 seedlings screened, 0.3 to 0.4% exhibited altered gravitropism. In approximately 40% of these mutant lines, only gravitropism by the root or the hypocotyl was altered, while the response of the other organ was unaffected. These data support the hypothesis that root and hypocotyl gravitropism are genetically separable. PMID:11537704

  11. A direct screening procedure for gravitropism mutants in Arabidopsis thaliana (L.) Heynh.

    Science.gov (United States)

    Bullen, B L; Best, T R; Gregg, M M; Barsel S-E; Poff, K L

    1990-01-01

    In order to isolate gravitropism mutants of Arabidopsis thaliana (L.) Heynh. var Estland for the genetic dissection of the gravitropism pathway, a direct screening procedure has been developed in which mutants are selected on the basis of their gravitropic response. Variability in hypocotyl curvature was dependent on the germination time of each seed stock, resulting in the incorrect identification of several lines as gravitropism mutants when a standard protocol for the potentiation of germination was used. When the protocol was adjusted to allow for differences in germination time, these lines were eliminated from the collection. Out of the 60,000 M2 seedlings screened, 0.3 to 0.4% exhibited altered gravitropism. In approximately 40% of these mutant lines, only gravitropism by the root or the hypocotyl was altered, while the response of the other organ was unaffected. These data support the hypothesis that root and hypocotyl gravitropism are genetically separable. PMID:11537704

  12. 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.

  13. X-ray and fast neutron-induced mutations in Arabidopsis thaliana, and the effect of dithiothreitol upon the mutant spectrum

    International Nuclear Information System (INIS)

    The author discusses the genetic effects of X-ray and fast neutron seed-irradiation of Arabidopsis thaliana (L.) Heynh., and the influence of a pre-irradiation treatment with the radio-protector dithiothreitol (DTT). (Auth.)

  14. Interaction of proline, sugars, and anthocyanins during photosynthetic acclimation of Arabidopsis thaliana to drought stress.

    Science.gov (United States)

    Sperdouli, Ilektra; Moustakas, Michael

    2012-04-15

    The relationships among photosynthetic acclimation, proline (Pro), soluble sugar (SS), and anthocyanin (An) accumulation in Arabidopsis thaliana leaves to the onset of drought stress (OnDS), mild (MiDS) and moderate drought stress (MoDS), were evaluated. As leaf water content (LWC) decreased, metabolic concentrations (Pro, SS, and An) increased and were negatively and significantly correlated with LWC. Thus, these metabolites may have an important role in the acclimation process to drought stress (DS). No correlations among Pro, SS and An accumulation with the quantum efficiency of PSII photochemistry (Φ(PSII)) and the excitation pressure (1-q(P)) were observed under DS. This implies that, while metabolites increased in a drought-dependent way, PSII activity did not decrease in the same pattern. Our results indicated that, under MoDS, A. thaliana leaves were able to maintain oxidative compounds such as malondialdeyde, an end product of lipid peroxidation, within the range of control leaves, and to cope with oxidative damage, as was evident by the decreased excitation pressure (1-q(P)) and similar (ns difference) Φ(PSII) to that of control leaves. In addition, a statistically significant increased accumulation of Pro, SS and An was recorded only under MoDS compared to controls. The better PSII functioning of MoDS Arabidopsis leaves may reflect the greater capacity of these leaves to undertake key metabolic adjustments, including increased Pro, SS and An accumulation, to maintain a higher antioxidant protection and a better balance between light capture and energy use. PMID:22305050

  15. 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. PMID:21388819

  16. Salt stress induces internalization of plasma membrane aquaporin into the vacuole in Arabidopsis thaliana.

    Science.gov (United States)

    Ueda, Masamichi; Tsutsumi, Nobuhiro; Fujimoto, Masaru

    2016-06-10

    Salt stress is a major environmental stress for plants, causing hyperosmotic, ionic and drought-like stresses. Plasma membrane intrinsic protein 2;1 (PIP2;1), which forms a water channel that regulates water flux thorough the plasma membrane (PM), is constitutively trafficked between the PM and the trans-Golgi network (TGN) in Arabidopsis thaliana. Salt stress is known to relocalize PIP2;1 to intracellular compartments, probably to decrease the water permeability of the root. However, the destination of internalized PIP2;1 and the mechanism by which PIP2;1 is internalized remain unclear. Here, we examined the effects of salt stress and inhibitors of endocytosis on the intracellular localization of green fluorescent protein-fused PIP2;1 (GFP-PIP2;1) in Arabidopsis thaliana root epidermal cells. Salt stress decreased the fluorescence of GFP-PIP2;1 at the PM and increased it in the vacuolar lumen as shown by staining of the vacuolar membrane. The internalization of PIP2;1 was suppressed by an inhibitor of clathrin-mediated endocytosis and by inhibitors of two kinases that appear to have roles in salt stress, phosphatidylinositol 3-kinase (PI3K) and phosphatidylinositol 4-kinase (PI4K). Inhibiting PI4K suppressed the salt-induced endocytosis of GFP-PIP2;1 at the PM, whereas inhibiting PI3K suppressed the trafficking of GFP-PIP2;1 after its internalization. These results suggest that salt stress induces the internalization of PIP2;1 from the PM to the vacuolar lumen, and that these processes are dependent on clathrin, PI3K and PI4K. PMID:27163638

  17. Transient effect of weak electromagnetic fields on calcium ion concentration in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Rassadina Valentina

    2009-04-01

    Full Text Available Abstract Background Weak magnetic and electromagnetic fields can influence physiological processes in animals, plants and microorganisms, but the underlying way of perception is poorly understood. The ion cyclotron resonance is one of the discussed mechanisms, predicting biological effects for definite frequencies and intensities of electromagnetic fields possibly by affecting the physiological availability of small ions. Above all an influence on Calcium, which is crucial for many life processes, is in the focus of interest. We show that in Arabidopsis thaliana, changes in Ca2+-concentrations can be induced by combinations of magnetic and electromagnetic fields that match Ca2+-ion cyclotron resonance conditions. Results An aequorin expressing Arabidopsis thaliana mutant (Col0-1 Aeq Cy+ was subjected to a magnetic field around 65 microtesla (0.65 Gauss and an electromagnetic field with the corresponding Ca2+ cyclotron frequency of 50 Hz. The resulting changes in free Ca2+ were monitored by aequorin bioluminescence, using a high sensitive photomultiplier unit. The experiments were referenced by the additional use of wild type plants. Transient increases of cytosolic Ca2+ were observed both after switching the electromagnetic field on and off, with the latter effect decreasing with increasing duration of the electromagnetic impact. Compared with this the uninfluenced long-term loss of bioluminescence activity without any exogenic impact was negligible. The magnetic field effect rapidly decreased if ion cyclotron resonance conditions were mismatched by varying the magnetic fieldstrength, also a dependence on the amplitude of the electromagnetic component was seen. Conclusion Considering the various functions of Ca2+ as a second messenger in plants, this mechanism may be relevant for perception of these combined fields. The applicability of recently hypothesized mechanisms for the ion cyclotron resonance effect in biological systems is discussed

  18. PpCBF3 from Cold-Tolerant Kentucky Bluegrass Involved in Freezing Tolerance Associated with Up-Regulation of Cold-Related Genes in Transgenic Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Lili Zhuang

    Full Text Available Dehydration-Responsive Element Binding proteins (DREB/C-repeat (CRT Binding Factors (CBF have been identified as transcriptional activators during plant responses to cold stress. The objective of this study was to determine the physiological roles of a CBF gene isolated from a cold-tolerant perennial grass species, Kentucky bluegrass (Poa pratensis L., which designated as PpCBF3, in regulating plant tolerance to freezing stress. Transient transformation of Arabidopsis thaliana mesophyll protoplast with PpCBF3-eGFP fused protein showed that PpCBF3 was localized to the nucleus. RT-PCR analysis showed that PpCBF3 was specifically induced by cold stress (4°C but not by drought stress [induced by 20% polyethylene glycol 6000 solution (PEG-6000] or salt stress (150 mM NaCl. Transgenic Arabidopsis overexpressing PpCBF3 showed significant improvement in freezing (-20°C tolerance demonstrated by a lower percentage of chlorotic leaves, lower cellular electrolyte leakage (EL and H2O2 and O2.- content, and higher chlorophyll content and photochemical efficiency compared to the wild type. Relative mRNA expression level analysis by qRT-PCR indicated that the improved freezing tolerance of transgenic Arabidopsis plants overexpressing PpCBF3 was conferred by sustained activation of downstream cold responsive (COR genes. Other interesting phenotypic changes in the PpCBF3-transgenic Arabidopsis plants included late flowering and slow growth or 'dwarfism', both of which are desirable phenotypic traits for perennial turfgrasses. Therefore, PpCBF3 has potential to be used in genetic engineering for improvement of turfgrass freezing tolerance and other desirable traits.

  19. Arsenic Methylation in Arabidopsis thaliana Expressing an Algal Arsenite Methyltransferase Gene Increases Arsenic Phytotoxicity.

    Science.gov (United States)

    Tang, Zhong; Lv, Yanling; Chen, Fei; Zhang, Wenwen; Rosen, Barry P; Zhao, Fang-Jie

    2016-04-01

    Arsenic (As) contamination in soil can lead to elevated transfer of As to the food chain. One potential mitigation strategy is to genetically engineer plants to enable them to transform inorganic As to methylated and volatile As species. In this study, we genetically engineered two ecotypes of Arabidopsis thaliana with the arsenite (As(III)) S-adenosylmethyltransferase (arsM) gene from the eukaryotic alga Chlamydomonas reinhardtii. The transgenic A. thaliana plants gained a strong ability to methylate As, converting most of the inorganic As into dimethylarsenate [DMA(V)] in the shoots. Small amounts of volatile As were detected from the transgenic plants. However, the transgenic plants became more sensitive to As(III) in the medium, suggesting that DMA(V) is more phytotoxic than inorganic As. The study demonstrates a negative consequence of engineered As methylation in plants and points to a need for arsM genes with a strong ability to methylate As to volatile species. PMID:26998776

  20. Purification, crystallization and preliminary crystallographic analysis of Arabidopsis thaliana imidazoleglycerol-phosphate dehydratase

    International Nuclear Information System (INIS)

    Imidazoleglycerol-phosphate dehydratase from A. thaliana has been overexpressed, purified and crystallized and data have been collected to 3 Å resolution. Imidazoleglycerol-phosphate dehydratase catalyses the sixth step of the histidine-biosynthesis pathway in plants and microorganisms and has been identified as a possible target for the development of novel herbicides. Arabidopsis thaliana IGPD has been cloned and overexpressed in Escherichia coli, purified and subsequently crystallized in the presence of manganese. Under these conditions, the inactive trimeric form of the metal-free enzyme is assembled into a fully active species consisting of a 24-mer exhibiting 432 symmetry. X-ray diffraction data have been collected to 3.0 Å resolution from a single crystal at 293 K. The crystal belongs to space group R3, with approximate unit-cell parameters a = b = 157.9, c = 480.0 Å, α = β = 90, γ = 120° and with either 16 or 24 subunits in the asymmetric unit. A full structure determination is under way in order to provide insights into the mode of subunit assembly and to initiate a programme of rational herbicide design

  1. 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. PMID:25488978

  2. Induction of Nickel Accumulation in Response to Zinc Deficiency in Arabidopsis thaliana

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    Sho Nishida

    2015-04-01

    Full Text Available 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.

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. Arabidopsis thaliana IRX10 and two related proteins from psyllium and Physcomitrella patens are xylan xylosyltransferases.

    Science.gov (United States)

    Jensen, Jacob Krüger; Johnson, Nathan Robert; Wilkerson, Curtis Gene

    2014-10-01

    The enzymatic mechanism that governs the synthesis of the xylan backbone polymer, a linear chain of xylose residues connected by β-1,4 glycosidic linkages, has remained elusive. Xylan is a major constituent of many kinds of plant cell walls, and genetic studies have identified multiple genes that affect xylan formation. In this study, we investigate several homologs of one of these previously identified xylan-related genes, IRX10 from Arabidopsis thaliana, by heterologous expression and in vitro xylan xylosyltransferase assay. We find that an IRX10 homolog from the moss Physcomitrella patens displays robust activity, and we show that the xylosidic linkage formed is a β-1,4 linkage, establishing this protein as a xylan β-1,4-xylosyltransferase. We also find lower but reproducible xylan xylosyltransferase activity with A. thaliana IRX10 and with a homolog from the dicot plant Plantago ovata, showing that xylan xylosyltransferase activity is conserved over large evolutionary distance for these proteins. PMID:25139408

  8. Effects of elevated carbon dioxide and sucrose concentrations on Arabidopsis thaliana root architecture and anatomy

    International Nuclear Information System (INIS)

    Plant root growth is known to be influenced by higher levels of atmospheric carbon dioxide (CO2). Roots of some species grown in hydroponics under elevated CO2 concentrations may be more competitive sinks for photosynthetic assimilates than roots grown under lower CO2 conditions. Root branching patterns may also be influenced by elevated CO2 concentrations. Studies have also shown that factors such as soil compaction, salinity and the availability of nitrate, phosphorous, oxygen and water also influence root growth, and the effects of higher CO2 on roots can be confounded by such environmental factors. This study evaluated the effects of elevated carbon dioxide and sucrose concentrations on Arabidopsis thaliana root growth, morphology, and architecture. Both ambient and elevated CO2 levels were used along with various sucrose concentrations. The study revealed that A. thaliana plants grown on a phytagar medium in small chambers with elevated CO2 had longer roots, more lateral root growth than plants grown in ambient CO2. Roots in elevated CO2 were found to have wider root diameters, and more secondary growth. The addition of sucrose to the media closely resembled the effects of elevated CO2. In addition, the increase in sucrose concentration had a bigger effect on root morphology under ambient, than elevated CO2. Therefore, both elevated CO2 and increased sucrose concentrations promote root growth by increasing their number, length, and diameter. The dichotomy branching index (DBI) also dropped resulting in a more dichotomous branching pattern. 34 refs., 5 figs

  9. The novel elicitor AsES triggers a defense response against Botrytis cinerea in Arabidopsis thaliana.

    Science.gov (United States)

    Hael-Conrad, V; Abou-Mansour, E; Díaz-Ricci, J-C; Métraux, J-P; Serrano, M

    2015-12-01

    AsES (Acremonium strictum Elicitor and Subtilisin) is a novel extracellular elicitor protein produced by the avirulent isolate SS71 of the opportunist strawberry fungal pathogen A. strictum. Here we describe the activity of AsES in the plant-pathogen system Arabidopsis thaliana-Botrytis cinerea. We show that AsES renders A. thaliana plants resistant to the necrotrophic pathogen B. cinerea, both locally and systemically and the defense response observed is dose-dependent. Systemic, but not local resistance is dependent on the length of exposure to AsES. The germination of the spores in vitro was not inhibited by AsES, implying that protection to B. cinerea is due to the induction of the plant defenses. These results were further supported by the findings that AsES differentially affects mutants impaired in the response to salicylic acid, jasmonic acid and ethylene, suggesting that AsES triggers the defense response through these three signaling pathways. PMID:26706064

  10. 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.

  11. 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

    2016-01-01

    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. PMID:27212081

  12. Century-scale methylome stability in a recently diverged Arabidopsis thaliana lineage.

    Science.gov (United States)

    Hagmann, Jörg; Becker, Claude; Müller, Jonas; Stegle, Oliver; Meyer, Rhonda C; Wang, George; Schneeberger, Korbinian; Fitz, Joffrey; Altmann, Thomas; Bergelson, Joy; Borgwardt, Karsten; Weigel, Detlef

    2015-01-01

    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. PMID:25569172

  13. Crystallization and preliminary X-ray analysis of cryptochrome 3 from Arabidopsis thaliana

    International Nuclear Information System (INIS)

    Recombinant cryptochrome 3 from A. thaliana with FAD and MTHF cofactors has been crystallized using the hanging-drop vapour-diffusion technique in the orthorhombic space group P212121 and X-ray diffraction data were collected to 1.9 Å resolution. Cryptochromes are flavoproteins which serve as blue-light receptors in plants, animals, fungi and prokaryotes and belong to the same protein family as the catalytically active DNA photolyases. Cryptochrome 3 from the plant Arabidopsis thaliana (cry3; 525 amino acids, 60.7 kDa) is a representative of the novel cryDASH subfamily of UV-A/blue-light receptors and has been expressed as a mature FAD-containing protein in Escherichia coli without the signal sequence that directs the protein into plant organelles. The purified cryptochrome was found to be complexed to methenyltetrahydrofolate as an antenna pigment. Crystals of the cryptochrome–antenna pigment complex were obtained by vapour diffusion and display orthorhombic symmetry, with unit-cell parameters a = 76.298, b = 116.782, c = 135.024 Å. X-ray diffraction data were collected to 1.9 Å resolution using synchrotron radiation. The asymmetric unit comprises a cry3 dimer, the physiological role of which remains to be elucidated

  14. 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.

  15. AINTEGUMENTA and AINTEGUMENTA-LIKE6/PLETHORA3 Induce LEAFY Expression in Response to Auxin to Promote the Onset of Flower Formation in Arabidopsis1[OPEN

    Science.gov (United States)

    Yamaguchi, Nobutoshi; Nole-Wilson, Staci; Wagner, Doris

    2016-01-01

    Proper timing of the onset to flower formation is critical for reproductive success. Monocarpic plants like Arabidopsis (Arabidopsis thaliana) switch from production of branches in the axils of leaves to that of flowers once in their lifecycle, during the meristem identity transition. The plant-specific transcription factor LEAFY (LFY) is necessary and sufficient for this transition. Previously, we reported that the plant hormone auxin induces LFY expression through AUXIN RESPONSE FACTOR5/MONOPTEROS (ARF5/MP). It is not known whether MP is solely responsible for auxin-directed transcriptional activation of LFY. Here, we show that two transcription factors belonging to the AINTEGUMENTA-LIKE/PLETHORA family, AINTEGUMENTA (ANT) and AINTEGUMENTA-LIKE6/PLETHORA3 (AIL6/PLT3), act in parallel with MP to upregulate LFY in response to auxin. ant ail6 mutants display a delay in the meristem identity transition and in LFY induction. ANT and AIL6/PLT3 are expressed prior to LFY and bind to the LFY promoter to control LFY mRNA accumulation. Genetic and promoter/reporter studies suggest that ANT/AIL6 act in parallel with MP to promote LFY induction in response to auxin sensing. Our study highlights the importance of two separate auxin-controlled pathways in the meristem identity transition. PMID:26537561

  16. Crystallization and preliminary X-ray diffraction study of a cell-wall invertase from Arabidopsis thaliana

    International Nuclear Information System (INIS)

    Crystals suitable for structural analysis have been prepared from a cell-wall invertase from A. thaliana. Cell-wall invertase 1 (AtcwINV1), a plant protein from Arabidopsis thaliana which is involved in the breakdown of sucrose, has been crystallized in two different crystal forms. Crystal form I grows in space group P31 or P32, whereas crystal form II grows in space group C2221. Data sets were collected for crystal forms I and II to resolution limits of 2.40 and 2.15 Å, respectively

  17. Constitutively expressed ERF-VII transcription factors redundantly activate the core anaerobic response in Arabidopsis thaliana.

    Science.gov (United States)

    Bui, Liem T; Giuntoli, Beatrice; Kosmacz, Monika; Parlanti, Sandro; Licausi, Francesco

    2015-07-01

    Plant adaptation to hypoxic conditions is mediated by the transcriptional activation of genes involved in the metabolic reprogramming of plant cells to cope with reduced oxygen availability. Recent studies indicated that members of the group VII of the Ethylene Responsive Transcription Factor (ERFs) family act as positive regulators of this molecular response. In the current study, the five ERF-VII transcription factors of Arabidopsis thaliana were compared to infer a hierarchy in their role with respect to the anaerobic response. When the activity of each transcription factor was tested on a set of hypoxia-responsive promoters, RAP2.2, RAP2.3 and RAP2.12 appeared to be the most powerful activators. RAP2.12 was further dissected in transactivation assays in Arabidopsis protoplasts to identify responsible regions for transcriptional activation. An ultimate C-terminal motif was identified as sufficient to drive gene transcription. Finally, using realtime RT-PCR in single and double mutants for the corresponding genes, we confirmed that RAP2.2 and RAP2.12 exert major control upon the anaerobic response. PMID:26025519

  18. Uncovering microRNA-mediated response to SO2 stress in Arabidopsis thaliana by deep sequencing.

    Science.gov (United States)

    Li, Lihong; Xue, Meizhao; Yi, Huilan

    2016-10-01

    Sulfur dioxide (SO2) is a major air pollutant and has significant impacts on plants. MicroRNAs (miRNAs) are a class of gene expression regulators that play important roles in response to environmental stresses. In this study, deep sequencing was used for genome-wide identification of miRNAs and their expression profiles in response to SO2 stress in Arabidopsis thaliana shoots. A total of 27 conserved miRNAs and 5 novel miRNAs were found to be differentially expressed under SO2 stress. qRT-PCR analysis showed mostly negative correlation between miRNA accumulation and target gene mRNA abundance, suggesting regulatory roles of these miRNAs during SO2 exposure. The target genes of SO2-responsive miRNAs encode transcription factors and proteins that regulate auxin signaling and stress response, and the miRNAs-mediated suppression of these genes could improve plant resistance to SO2 stress. Promoter sequence analysis of genes encoding SO2-responsive miRNAs showed that stress-responsive and phytohormone-related cis-regulatory elements occurred frequently, providing additional evidence of the involvement of miRNAs in adaption to SO2 stress. This study represents a comprehensive expression profiling of SO2-responsive miRNAs in Arabidopsis and broads our perspective on the ubiquitous regulatory roles of miRNAs under stress conditions. PMID:27232729

  19. Oxygen control of ethylene biosynthesis during seed development in Arabidopsis thaliana (L.) Heynh

    Science.gov (United States)

    Ramonell, K. M.; McClure, G.; Musgrave, M. E.

    2002-01-01

    An unforeseen side-effect on plant growth in reduced oxygen is the loss of seed production at concentrations around 25% atmospheric (50 mmol mol-1 O2). In this study, the model plant Arabidopsis thaliana (L.) Heynh. cv. 'Columbia' was used to investigate the effect of low oxygen on ethylene biosynthesis during seed development. Plants were grown in a range of oxygen concentrations (210 [equal to ambient], 160, 100, 50 and 25 mmol mol-1) with 0.35 mmol mol-1 CO2 in N2. Ethylene in full-sized siliques was sampled using gas chromatography, and viable seed production was determined at maturity. Molecular analysis of ethylene biosynthesis was accomplished using cDNAs encoding 1-aminocyclopropane-1-carboxylic acid (ACC) synthase and ACC oxidase in ribonuclease protection assays and in situ hybridizations. No ethylene was detected in siliques from plants grown at 50 and 25 mmol mol-1 O2. At the same time, silique ACC oxidase mRNA increased three-fold comparing plants grown under the lowest oxygen with ambient controls, whereas ACC synthase mRNA was unaffected. As O2 decreased, tissue-specific patterning of ACC oxidase and ACC synthase gene expression shifted from the embryo to the silique wall. These data demonstrate how low O2 modulates the activity and expression of the ethylene biosynthetic pathway during seed development in Arabidopsis.

  20. Molecular characterization of multiple cDNA clones for ADP-glucose pyrophosphorylase from Arabidopsis thaliana.

    Science.gov (United States)

    Villand, P; Olsen, O A; Kleczkowski, L A

    1993-12-01

    PCR amplification of cDNA prepared from poly(A)+ RNA from aerial parts of Arabidopsis thaliana, using degenerate nucleotide primers based on conserved regions between the large and small subunits of ADP-glucose pyrophosphorylase (AGP), yielded four different cDNAs of ca. 550 nucleotides each. Based on derived amino acid sequences, the identities between the clones varied from 49 to 69%. Sequence comparison to previously published cDNAs for AGP from various species and tissues has revealed that three of the amplified cDNAs (ApL1, ApL2 and ApL3) correspond to the large subunit of AGP, and one cDNA (ApS) encodes the small subunit of AGP. Both ApL1 and ApS were subsequently found to be present in a cDNA library made from Arabidopsis leaves. All four PCR products are encoded by single genes, as found by genomic Southern analysis. PMID:8292792

  1. Towards Interoperability in Genome Databases: The MAtDB (MIPS Arabidopsis Thaliana Database) Experience.

    Science.gov (United States)

    Schoof, Heiko

    2003-01-01

    Increasing numbers of whole-genome sequences are available, but to interpret them fully requires more than listing all genes. Genome databases are faced with the challenges of integrating heterogenous data and enabling data mining. In comparison to a data warehousing approach, where integration is achieved through replication of all relevant data in a unified schema, distributed approaches provide greater flexibility and maintainability. These are important in a field where new data is generated rapidly and our understanding of the data changes. Interoperability between distributed data sources allows data maintenance to be separated from integration and analysis. Simple ways to access the data can facilitate the development of new data mining tools and the transition from model genome analysis to comparative genomics. With the MIPS Arabidopsis thaliana genome database (MAtDB, http://mips.gsf.de/proj/thal/db) our aim is to go beyond a data repository towards creating an integrated knowledge resource. To this end, the Arabidopsis genome has been a backbone against which to structure and integrate heterogenous data. The challenges to be met are continuous updating of data, the design of flexible data models that can evolve with new data, the integration of heterogenous data, e.g. through the use of ontologies, comprehensive views and visualization of complex information, simple interfaces for application access locally or via the Internet, and knowledge transfer across species. PMID:18629123

  2. Towards Interoperability in Genome Databases: The MAtDB (MIPS Arabidopsis Thaliana Database Experience

    Directory of Open Access Journals (Sweden)

    Heiko Schoof

    2006-04-01

    Full Text Available Increasing numbers of whole-genome sequences are available, but to interpret them fully requires more than listing all genes. Genome databases are faced with the challenges of integrating heterogenous data and enabling data mining. In comparison to a data warehousing approach, where integration is achieved through replication of all relevant data in a unified schema, distributed approaches provide greater flexibility and maintainability. These are important in a field where new data is generated rapidly and our understanding of the data changes. Interoperability between distributed data sources allows data maintenance to be separated from integration and analysis. Simple ways to access the data can facilitate the development of new data mining tools and the transition from model genome analysis to comparative genomics. With the MIPS Arabidopsis thaliana genome database (MAtDB, http://mips.gsf.de/proj/thal/db our aim is to go beyond a data repository towards creating an integrated knowledge resource. To this end, the Arabidopsis genome has been a backbone against which to structure and integrate heterogenous data. The challenges to be met are continuous updating of data, the design of flexible data models that can evolve with new data, the integration of heterogenous data, e.g. through the use of ontologies, comprehensive views and visualization of complex information, simple interfaces for application access locally or via the Internet, and knowledge transfer across species.

  3. Efficient Silencing of Endogenous MicroRNAs Using Artificial MicroRNAs in Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    Andrew L. Eamens; Claire Agius; Neil A. Smith; Peter M. Waterhouse; Ming-Bo Wang

    2011-01-01

    We report here that the expression of endogenous microRNAs (miRNAs) can be efficiently silenced in Arabidopsis thaliana (Arabidopsis) using artificial miRNA (amiRNA) technology. We demonstrate that an amiRNA designed to target a mature miRNA directs silencing against all miRNA family members, whereas an amiRNA designed to target the stem-loop region of a miRNA precursor transcript directs silencing against only the individual family member targeted.Furthermore, our results indicate that amiRNAs targeting both the mature miRNA and stem-loop sequence direct RNA silencing through cleavage of the miRNA precursor transcript, which presumably occurs in the nucleus of a plant cell during the initial stages of miRNA biogenesis. This suggests that small RNA (sRNA)-guided RNA cleavage in plants occurs not only in the cytoplasm, but also in the nucleus. Many plant miRNA gene families have been identified via sequencing and bioinformatic analysis, but, to date, only a small tranche of these have been functionally characterized due to a lack of effective forward or reverse genetic tools. Our findings therefore provide a new and powerful reverse-genetic tool for the analysis of miRNA function in plants.

  4. 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.

  5. Arabidopsis thaliana WAPL is essential for the prophase removal of cohesin during meiosis.

    Directory of Open Access Journals (Sweden)

    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.

  6. Structural and Functional Studies of the Mitochondrial Cysteine Desulfurase from Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    Valeria R; Turowski; Maria V.Busi; Diego F.Gomez-Casati

    2012-01-01

    AtNfs1 is the Arabidopsis thaliana mitochondrial homolog of the bacterial cysteine desulfurases NifS and lscS,having an essential role in cellular Fe-S cluster assembly.Homology modeling of AtNfs1m predicts a high global similarity with E.coli IscS showing a full conservation of residues involved in the catalytic site,whereas the chloroplastic AtNfs2 is more similar to the Synechocystis sp.SufS.Pull-down assays showed that the recombinant mature form,AtNfs1m,specifically binds to Arabidopsis frataxin (AtFH).A hysteretic behavior,with a lag phase of several minutes,was observed and hysteretic parameters were affected by pre-incubation with AtFH.Moreover,AtFH modulates AtNfs1m kinetics,increasing Vmax and decreasing the S0.5 value for cysteine.Results suggest that AtFH plays an important role in the early steps of Fe-S cluster formation by regulating AtNfs1 activity in olant mitochondria.

  7. Pectin Biosynthesis Is Critical for Cell Wall Integrity and Immunity in Arabidopsis thaliana.

    Science.gov (United States)

    Bethke, Gerit; Thao, Amanda; Xiong, Guangyan; Li, Baohua; Soltis, Nicole E; Hatsugai, Noriyuki; Hillmer, Rachel A; Katagiri, Fumiaki; Kliebenstein, Daniel J; Pauly, Markus; Glazebrook, Jane

    2016-02-01

    Plant cell walls are important barriers against microbial pathogens. Cell walls of Arabidopsis thaliana leaves contain three major types of polysaccharides: cellulose, various hemicelluloses, and pectins. UDP-d-galacturonic acid, the key building block of pectins, is produced from the precursor UDP-d-glucuronic acid by the action of glucuronate 4-epimerases (GAEs). Pseudomonas syringae pv maculicola ES4326 (Pma ES4326) repressed expression of GAE1 and GAE6 in Arabidopsis, and immunity to Pma ES4326 was compromised in gae6 and gae1 gae6 mutant plants. These plants had brittle leaves and cell walls of leaves had less galacturonic acid. Resistance to specific Botrytis cinerea isolates was also compromised in gae1 gae6 double mutant plants. Although oligogalacturonide (OG)-induced immune signaling was unaltered in gae1 gae6 mutant plants, immune signaling induced by a commercial pectinase, macerozyme, was reduced. Macerozyme treatment or infection with B. cinerea released less soluble uronic acid, likely reflecting fewer OGs, from gae1 gae6 cell walls than from wild-type Col-0. Although both OGs and macerozyme-induced immunity to B. cinerea in Col-0, only OGs also induced immunity in gae1 gae6. Pectin is thus an important contributor to plant immunity, and this is due at least in part to the induction of immune responses by soluble pectin, likely OGs, that are released during plant-pathogen interactions. PMID:26813622

  8. Construction of a chloroplast protein interaction network and functional mining of photosynthetic proteins in Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    Qing-Bo Yu; Yong-Lan Cui; Kang Chong; Yi-Xue Li; Yu-Hua Li; Zhongming Zhao; Tie-Liu Shi; Zhong-Nan Yang; Guang Li; Guan Wang; Jing-Chun Sun; Peng-Cheng Wang; Chen Wang; Hua-Ling Mi; Wei-Min Ma; Jian Cui

    2008-01-01

    Chloroplast is a typical plant cell organeUe where photosynthesis takes place.In this study,a total of 1 808 chloroplast core proteins in Arabidopsis thaliana were reliably identified by combining the results of previously published studies and our own predictions.We then constructed a chloroplast protein interaction network primarily based on these core protein interactions.The network had 22 925 protein interaction pairs which involved 2 214 proteins.A total of 160 previously uncharacterized proteins were annotated in this network.The subunits of the photosynthetic complexes were modularized,and the functional relationships among photosystem Ⅰ (PSI),photosystem Ⅱ (PSII),light harvesting complex of photosystem Ⅰ (LHC Ⅰ) and light harvesting complex of photosystem Ⅰ (LHC Ⅱ) could be deduced from the predicted protein interactions in this network.We further confirmed an interaction between an unknown protein AT1G52220 and a photosynthetic subunit PSI-D2 by yeast two-hybrid analysis.Our chloroplast protein interaction network should be useful for functional mining of photosynthetic proteins and investigation of chloroplast-related functions at the systems biology level in Arabidopsis.

  9. Metal binding affinity and structural properties of calmodulin-like protein 14 from Arabidopsis thaliana.

    Science.gov (United States)

    Vallone, Rosario; La Verde, Valentina; D'Onofrio, Mariapina; Giorgetti, Alejandro; Dominici, Paola; Astegno, Alessandra

    2016-08-01

    In addition to the well-known Ca(2+) sensor calmodulin, plants possess many calmodulin-like proteins (CMLs) that are predicted to have specific roles in the cell. Herein, we described the biochemical and biophysical characterization of recombinant Arabidopsis thaliana CML14. We applied isothermal titration calorimetry to analyze the energetics of Ca(2+) and Mg(2+) binding to CML14, and nuclear magnetic resonance spectroscopy, together with intrinsic and ANS-based fluorescence, to evaluate the structural effects of metal binding and metal-induced conformational changes. Furthermore, differential scanning calorimetry and limited proteolysis were used to characterize protein thermal and local stability. Our data demonstrate that CML14 binds one Ca(2+) ion with micromolar affinity (Kd ∼ 12 µM) and the presence of 10 mM Mg(2+) decreases the Ca(2+) affinity by ∼5-fold. Although binding of Ca(2+) to CML14 increases protein stability, it does not result in a more hydrophobic protein surface and does not induce the large conformational rearrangement typical of Ca(2+) sensors, but causes only localized structural changes in the unique functional EF-hand. Our data, together with a molecular modelling prediction, provide interesting insights into the biochemical properties of Arabidopsis CML14 and may be useful to direct additional studies aimed at understanding its physiological role. PMID:27124620

  10. Analysis of DNA repair helicase UvrD from Arabidopsis thaliana and Oryza sativa.

    Science.gov (United States)

    Tuteja, Renu; Tuteja, Narendra

    2013-10-01

    Mismatch repair (MMR) proteins play important roles in maintaining genome stability in all the organisms. Studies of MMR genes in plants have identified several homologs of the Escherichia coli genes. Crop yield is directly related to genome stability, which is crucially required for optimal plant growth and development. Numerous genotoxic stresses such as UV light, radiations, pollutants and heavy metals cause DNA damage leading to genome instability, which can interfere with the plant growth and crop productivity. But the efficient repair mechanisms can help to overcome the deleterious effects of the damage. Therefore it is important to study the genes involved in various repair pathways in the plants in greater detail. UvrD helicase is a component of MMR complex and plays an essential role in the DNA repair by providing the unwinding function. In the present manuscript we present an in silico analysis of UvrD helicase from two plant species (Arabidopsis and rice). The Arabidopsis thaliana and Oryza sativa UvrD are 1149 (~129 kDa) and 1165 amino-acids (~130 kDa) proteins, respectively. These proteins contain all the conserved domains and are larger than the E. coli UvrD because they contain a longer N-terminal extension. In order to decipher the role of plant UvrD in various stresses it will be important to study the biochemical and functional properties of this enzyme. PMID:23974358

  11. Structurally distinct Arabidopsis thaliana NLR immune receptors recognize tandem WY domains of an oomycete effector.

    Science.gov (United States)

    Goritschnig, Sandra; Steinbrenner, Adam D; Grunwald, Derrick J; Staskawicz, Brian J

    2016-05-01

    Nucleotide-binding leucine-rich repeat (NB-LRR, or NLR) receptors mediate pathogen recognition. The Arabidopsis thaliana NLR RPP1 recognizes the tandem WY-domain effector ATR1 from the oomycete Hyaloperonospora arabidopsidis through direct association with C-terminal LRRs. We isolated and characterized homologous NLR genes RPP1-EstA and RPP1-ZdrA from two Arabidopsis ecotypes, Estland (Est-1) and Zdarec (Zdr-1), responsible for recognizing a novel spectrum of ATR1 alleles. RPP1-EstA and -ZdrA encode nearly identical NLRs that are phylogenetically distinct from known immunity-activating RPP1 homologs and possess greatly expanded LRR domains. Site-directed mutagenesis and truncation analysis of ATR1 suggests that these homologs recognize a novel surface of the 2(nd) WY domain of ATR1, partially specified by a C-terminal region of the LRR domain. Synteny comparison with RPP1 loci involved in hybrid incompatibility suggests that these functions evolved independently. Closely related RPP1 homologs have diversified their recognition spectra through LRR expansion and sequence variation, allowing them to detect multiple surfaces of the same pathogen effector. Engineering NLR receptor specificity may require a similar combination of repeat expansion and tailored amino acid variation. PMID:26725254

  12. Effects of temperature on UV-B-induced DNA damage and photorepair in Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    LI Shao-shan; WANG Yan; BJ(O)RN Lars Olof

    2004-01-01

    DNA damage in the form of cyclobutane pyrimidine dimers(CPDs) and (6-4) photoproducts(6-4PPs) induced by UV-B radiation in Arabidopsis thaliana at different temperatures was investigated using ELISA with specific monoclonal antibodies. CPDs and 6-4PPs increased during 3 h UV-B exposure, but further exposure led to decreases. Contrary to the commonly accepted view that DNA damage induced by UV-B radiation is temperature-independent because of its photochemical nature, we found UV-B-induction of CPDs and 6-4PPs in Arabidopsis to be slower at a Iow than at a high temperature. Photorepair of CPDs at 24℃ was much faster than that at 0℃ and 12℃,with 50% CPDs removal during 1 h exposure to white light. Photorepair of 6-4PPs at 12℃ was very slow as compared with that at 24℃,and almost no removal of 6-4PPs was detected after 4 h exposure to white light at 0℃. There was evidence to suggest that temperaturedependent DNA damage and photorepair could have important ecological implications.

  13. Effect of magnetic fields on cryptochrome-dependent responses in Arabidopsis thaliana.

    Science.gov (United States)

    Harris, Sue-Re; Henbest, Kevin B; Maeda, Kiminori; Pannell, John R; Timmel, Christiane R; Hore, P J; Okamoto, Haruko

    2009-12-01

    The scientific literature describing the effects of weak magnetic fields on living systems contains a plethora of contradictory reports, few successful independent replication studies and a dearth of plausible biophysical interaction mechanisms. Most such investigations have been unsystematic, devoid of testable theoretical predictions and, ultimately, unconvincing. A recent study, of magnetic responses in the model plant Arabidopsis thaliana, however, stands out; it has a clear hypothesis-that seedling growth is magnetically sensitive as a result of photoinduced radical-pair reactions in cryptochrome photoreceptors-tested by measuring several cryptochrome-dependent responses, all of which proved to be enhanced in a magnetic field of intensity 500 muT. The potential importance of this study in the debate on putative effects of extremely low-frequency electromagnetic fields on human health prompted us to subject it to the 'gold standard' of independent replication. With experimental conditions chosen to match those of the original study, we have measured hypocotyl lengths and anthocyanin accumulation for Arabidopsis seedlings grown in a 500 microT magnetic field, with simultaneous control experiments at 50 microT. Additionally, we have determined hypocotyl lengths of plants grown in 50 microT, 1 mT and approximately 100 mT magnetic fields (with zero-field controls), measured gene (CHS, HY5 and GST) expression levels, investigated blue-light intensity effects and explored the influence of sucrose in the growth medium. In no case were consistent, statistically significant magnetic field responses detected. PMID:19324677

  14. Inference of the Genetic Network Regulating Lateral Root Initiation in Arabidopsis thaliana

    KAUST Repository

    Muraro, D.

    2013-01-01

    Regulation of gene expression is crucial for organism growth, and it is one of the challenges in systems biology to reconstruct the underlying regulatory biological networks from transcriptomic data. The formation of lateral roots in Arabidopsis thaliana is stimulated by a cascade of regulators of which only the interactions of its initial elements have been identified. Using simulated gene expression data with known network topology, we compare the performance of inference algorithms, based on different approaches, for which ready-to-use software is available. We show that their performance improves with the network size and the inclusion of mutants. We then analyze two sets of genes, whose activity is likely to be relevant to lateral root initiation in Arabidopsis, and assess causality of their regulatory interactions by integrating sequence analysis with the intersection of the results of the best performing methods on time series and mutants. The methods applied capture known interactions between genes that are candidate regulators at early stages of development. The network inferred from genes significantly expressed during lateral root formation exhibits distinct scale free, small world and hierarchical properties and the nodes with a high out-degree may warrant further investigation. © 2004-2012 IEEE.

  15. Advances in the understanding of cuticular waxes in Arabidopsis thaliana and crop species.

    Science.gov (United States)

    Lee, Saet Buyl; Suh, Mi Chung

    2015-04-01

    The aerial parts of plants are covered with a cuticle, a hydrophobic layer consisting of cutin polyester and cuticular waxes that protects them from various environmental stresses. Cuticular waxes mainly comprise very long chain fatty acids and their derivatives such as aldehydes, alkanes, secondary alcohols, ketones, primary alcohols, and wax esters that are also important raw materials for the production of lubricants, adhesives, cosmetics, and biofuels. The major function of cuticular waxes is to control non-stomatal water loss and gas exchange. In recent years, the in planta roles of many genes involved in cuticular wax biosynthesis have been characterized not only from model organisms like Arabidopsis thaliana and saltwater cress (Eutrema salsugineum), but also crop plants including maize, rice, wheat, tomato, petunia, Medicago sativa, Medicago truncatula, rapeseed, and Camelina sativa through genetic, biochemical, molecular, genomic, and cell biological approaches. In this review, we discuss recent advances in the understanding of the biological functions of genes involved in cuticular wax biosynthesis, transport, and regulation of wax deposition from Arabidopsis and crop species, provide information on cuticular wax amounts and composition in various organs of nine representative plant species, and suggest the important issues that need to be investigated in this field of study. PMID:25693495

  16. Transcriptional consequence and impaired gametogenesis with high-grade aneuploidy in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Kuan-Lin Lo

    Full Text Available Aneuploidy features a numerical chromosome variant that the number of chromosomes in the nucleus of a cell is not an exact multiple of the haploid number, which may have an impact on morphology and gene expression. Here we report a tertiary trisomy uncovered by characterizing a T-DNA insertion mutant (aur2-1/+ in the Arabidopsis (Arabidopsis thaliana AURORA2 locus. Whole-genome analysis with DNA tiling arrays revealed a chromosomal translocation linked to the aur2-1 allele, which collectively accounted for a tertiary trisomy 2. Morphologic, cytogenetic and genetic analyses of aur2-1 progeny showed impaired male and female gametogenesis to various degrees and a tight association of the aur2-1 allele with the tertiary trisomy that was preferentially inherited. Transcriptome analysis showed overlapping and distinct gene expression profiles between primary and tertiary trisomy 2 plants, particularly genes involved in response to stress and various types of external and internal stimuli. Additionally, transcriptome and gene ontology analyses revealed an overrepresentation of nuclear-encoded organelle-related genes functionally involved in plastids, mitochondria and peroxisomes that were differentially expressed in at least three if not all Arabidopsis trisomics. These observations support a previous hypothesis that aneuploid cells have higher energy requirement to overcome the detrimental effects of an unbalanced genome. Moreover, our findings extend the knowledge of the complex nature of the T-DNA insertion event influencing plant genomic integrity by creating high-grade trisomy. Finally, gene expression profiling results provide useful information for future research to compare primary and tertiary trisomics for the effects of aneuploidy on plant cell physiology.

  17. DNA-free RNA isolation protocols for Arabidopsis thaliana, including seeds and siliques

    Directory of Open Access Journals (Sweden)

    Vicente-Carbajosa Jesús

    2008-10-01

    Full Text Available Abstract Background High throughput applications of the reverse transcriptase quantitative PCR (RT-qPCR for quantification of gene expression demand straightforward procedures to isolate and analyze a considerable number of DNA-free RNA samples. Published protocols are labour intensive, use toxic organic chemicals and need a DNase digestion once pure RNAs have been isolated. In addition, for some tissues, the amount of starting material may be limiting. The convenience of commercial kits is often prohibitive when handling large number of samples. Findings We have established protocols to isolate DNA-free RNA from Arabidopsis thaliana tissues ready for RT-qPCR applications. Simple non-toxic buffers were used for RNA isolation from Arabidopsis tissues with the exception of seeds and siliques, which required the use of organic extractions. The protocols were designed to minimize the number of steps, labour time and the amount of starting tissue to as little as 10–20 mg without affecting RNA quality. In both protocols genomic DNA (gDNA can be efficiently removed from RNA samples before the final alcohol precipitation step, saving extra purification steps before cDNA synthesis. The expression kinetics of previously characterized genes confirmed the robustness of the procedures. Conclusion Here, we present two protocols to isolate DNA-free RNA from Arabidopsis tissues ready for RT-qPCR applications that significantly improve existing ones by reducing labour time and the use of organic extractions. Accessibility to these protocols is ensured by its simplicity and the low cost of the materials used.

  18. 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

  19. Gravitropism in Arabidopsis thaliana: violation of the sine- and resultant-law

    Science.gov (United States)

    Galland, Paul

    We investigated the gravitropic bending of hypocotyls and roots of seedlings of Arabidopsis tha-liana in response to long-term centrifugal accelerations in a range of 5 x 10-3 to 4 x g. The so-cal-led resultant law of gravitropism, a corollary of the so called sine law, claims that during centri-fugation a gravitropic organ aligns itself parallel to the resultant stimulus vector. We show here that neither of the two empirical “laws” is apt to describe the complex gravitropic behaviour of seedlings of Arabidopsis. Hypocotyls obey reasonably well the resultant law while roots display a complex behaviour that is clearly at variance with it. Horizontally centrifuged seedlings sense minute accelerations acting parallel to the longitudinal axis. If the centrifugal vector points to-ward the cotyledons, then the bending of hypocotyls and roots is greatly enhanced. If the centri-fugal vector points, however, toward the root tip, then only the bending of roots is enhanced by accelerations as low as 5 x 10-3 x g (positive tonic effect). The absolute gravitropic thresholds were determined for hypocotyls and roots in a clinostat-centrifuge and found to be near 1.5 x 10-2 x g. A behavioural mutant, ehb1-2 (Knauer et al. 2011), displays a lower gravitropic threshold for roots, not however, for hypocotyls. The complex gravitropic behaviour of seedlings of Arabi-dopsis is at odds with the classical sine- as well as the resultant law and can indicates the eminent role that is played by the acceleration vector operating longitudinally to the seedling axis.

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

    International Nuclear Information System (INIS)

    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 (∼61.4 %) responsive genes to ν -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 H2O2 scavenging activity in leaves were applied

  1. A circadian oscillator in the fungus Botrytis cinerea regulates virulence when infecting Arabidopsis thaliana.

    Science.gov (United States)

    Hevia, Montserrat A; Canessa, Paulo; Müller-Esparza, Hanna; Larrondo, Luis F

    2015-07-14

    The circadian clock of the plant model Arabidopsis thaliana modulates defense mechanisms impacting plant-pathogen interactions. Nevertheless, the effect of clock regulation on pathogenic traits has not been explored in detail. Moreover, molecular description of clocks in pathogenic fungi--or fungi in general other than the model ascomycete Neurospora crassa--has been neglected, leaving this type of question largely unaddressed. We sought to characterize, therefore, the circadian system of the plant pathogen Botrytis cinerea to assess if such oscillatory machinery can modulate its virulence potential. Herein, we show the existence of a functional clock in B. cinerea, which shares similar components and circuitry with the Neurospora circadian system, although we found that its core negative clock element FREQUENCY (BcFRQ1) serves additional roles, suggesting extracircadian functions for this protein. We observe that the lesions produced by this necrotrophic fungus on Arabidopsis leaves are smaller when the interaction between these two organisms occurs at dawn. Remarkably, this effect does not depend solely on the plant clock, but instead largely relies on the pathogen circadian system. Genetic disruption of the B. cinerea oscillator by mutation, overexpression of BcFRQ1, or by suppression of its rhythmicity by constant light, abrogates circadian regulation of fungal virulence. By conducting experiments with out-of-phase light:dark cycles, we confirm that indeed, it is the fungal clock that plays the main role in defining the outcome of the Arabidopsis-Botrytis interaction, providing to our knowledge the first evidence of a microbial clock modulating pathogenic traits at specific times of the day. PMID:26124115

  2. Non-specific phospholipase C4 mediates response to aluminum toxicity in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Přemysl ePejchar

    2015-02-01

    Full Text Available Aluminum ions (Al have been recognized as a major toxic factor for crop production in acidic soils. The first indication of the Al toxicity in plants is the cessation of root growth, but the mechanism of root growth inhibition is largely unknown. Here we examined the impact of Al on the expression, activity and function of the non-specific phospholipase C4 (NPC4, a plasma membrane-bound isoform of NPC, a member of the plant phospholipase family, in Arabidopsis thaliana.We observed a lower expression of NPC4 using GUS assay and a decreased formation of labeled diacylglycerol, product of NPC activity, using fluorescently labeled phosphatidylcholine as a phospholipase substrate in Arabidopsis WT seedlings treated with AlCl3 for 2 h. The effect on in situ NPC activity persisted for longer Al treatment periods (8, 14 h. Interestingly, in seedlings overexpressing NPC4, the Al-mediated NPC-inhibiting effect was alleviated at 14 h. However, in vitro activity and localization of NPC4 were not affected by Al, thus excluding direct inhibition by Al ions or possible translocation of NPC4 as the mechanisms involved in NPC-inhibiting effect. Furthermore, the growth of tobacco pollen tubes rapidly arrested by Al was partially rescued by the overexpression of AtNPC4 while Arabidopsis npc4 knockout lines were found to be more sensitive to Al stress during long-term exposure of Al at low phosphate conditions.Our observations suggest that NPC4 plays a role in both early and long-term responses to Al stress.

  3. 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.

  4. Phospholipase D affects translocation of NPR1 to the nucleus in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Martin eJanda

    2015-02-01

    Full Text Available Phytohormone salicylic acid (SA is a crucial component of plant induced defense against biotrophic pathogens. Although the key players of SA pathway are known, there are still gaps in our understanding of molecular mechanism and regulation of particular steps. In our previous research we showed in Arabidopsis suspension cells that n-butanol, which specifically modulates phospholipase D activity, significantly supresses transcription of pathogenesis related (PR1 gene generally accepted as SA pathway marker. In the presented study, we have investigated the site of n-butanol action in SA pathway. We were able to show in Arabidopsis plants treated with SA that n-butanol inhibits the transcription of defense genes (PR-1, WRKY38. Fluorescence microscopy of Arabidopsis thaliana mutants expressing 35S::NPR1-GFP (nonexpressor pathogenesis related 1 revealed significantly decreased nuclear localization of NPR1 in the presence of n-butanol. On the other hand, n-butanol did not affect nuclear localization of NPR1 in 35S::npr1C82A-GFP and 35S::npr1C216A-GFP mutants constitutively expressing NPR1 monomers. We also observed decreasing effect of n-butanol on ROS production, another important factor in plant response to pathogen attack.Mass spectrometric analysis of plant extracts showed that n-butanol significantly changes metabolic fingerprinting while t-butanol had no effect. We found groups of plant metabolites, influenced differently by SA and n-butanol treatment and we proposed several metabolites as markers for n-butanol action.

  5. Synthesis of oleyl oleate wax esters in Arabidopsis thaliana and Camelina sativa seed oil.

    Science.gov (United States)

    Iven, Tim; Hornung, Ellen; Heilmann, Mareike; Feussner, Ivo

    2016-01-01

    Seed oil composed of wax esters with long-chain monoenoic acyl moieties represents a high-value commodity for industry. Such plant-derived sperm oil-like liquid wax esters are biodegradable and can have excellent properties for lubrication. In addition, wax ester oil may represent a superior substrate for biodiesel production. In this study, we demonstrate that the low-input oil seed crop Camelina sativa can serve as a biotechnological platform for environmentally benign wax ester production. Two biosynthetic steps catalysed by a fatty alcohol-forming acyl-CoA reductase (FAR) and a wax ester synthase (WS) are sufficient to achieve wax ester accumulation from acyl-CoA substrates. To produce plant-derived sperm oil-like liquid wax esters, the WS from Mus musculus (MmWS) or Simmondsia chinensis (ScWS) were expressed in combination with the FAR from Mus musculus (MmFAR1) or Marinobacter aquaeolei (MaFAR) in seeds of Arabidopsis thaliana and Camelina sativa. The three analysed enzyme combinations Oleo3:mCherry:MmFAR1∆c/Oleo3:EYFP:MmWS, Oleo3:mCherry:MmFAR1∆c/ScWS and MaFAR/ScWS showed differences in the wax ester molecular species profiles and overall biosynthetic performance. By expressing MaFAR/ScWS in Arabidopsis or Camelina up to 59% or 21% of the seed oil TAGs were replaced by wax esters, respectively. This combination also yielded wax ester molecular species with highest content of monounsaturated acyl moieties. Expression of the enzyme combinations in the Arabidopsis fae1 fad2 mutant background high in oleic acid resulted in wax ester accumulation enriched in oleyl oleate (18:1/18:1 > 60%), suggesting that similar values may be obtained with a Camelina high oleic acid line. PMID:25912558

  6. The Half-Size ABC Transporter FOLDED PETALS 2/ABCG13 Is Involved in Petal Elongation through Narrow Spaces in Arabidopsis thaliana Floral Buds

    Directory of Open Access Journals (Sweden)

    Seiji Takeda

    2014-08-01

    Full Text Available Flowers are vital for attracting pollinators to plants and in horticulture for humans. Petal morphogenesis is a central process of floral development. Petal development can be divided into three main processes: the establishment of organ identity in a concentric pattern, primordia initiation at fixed positions within a whorl, and morphogenesis, which includes petal elongation through the narrow spaces within the bud. Here, we show that the FOLDED PETALS 2 (FOP2 gene, encoding a member of the half-size ATP binding cassette (ABC transporter family ABCG13, is involved in straight elongation of petals in Arabidopsis thaliana. In fop2 mutants, flowers open with folded petals, instead of straight-elongated ones found in the wild type. The epicuticular nanoridge structures are absent in many abaxial epidermal cells of fop2 petals, and surgical or genetic generation of space in young fop2 buds restores the straight elongation of petals, suggesting that the physical contact of sepals and petals causes the petal folding. Similar petal folding has been reported in the fop1 mutant, and the petals of fop2 fop1 double mutants resemble those of both the fop1 and fop2 single mutants, although the epidermal structure and permeability of the petal surface is more affected in fop2. Our results suggest that synthesis and transport of cutin or wax in growing petals play an important role for their smooth elongation through the narrow spaces of floral buds.

  7. 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.

  8. Proteome-wide survey of phosphorylation patterns affected by nuclear DNA polymorphisms in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Engelsberger Wolfgang R

    2010-07-01

    Full Text Available Abstract Background Protein phosphorylation is an important post-translational modification influencing many aspects of dynamic cellular behavior. Site-specific phosphorylation of amino acid residues serine, threonine, and tyrosine can have profound effects on protein structure, activity, stability, and interaction with other biomolecules. Phosphorylation sites can be affected in diverse ways in members of any species, one such way is through single nucleotide polymorphisms (SNPs. The availability of large numbers of experimentally identified phosphorylation sites, and of natural variation datasets in Arabidopsis thaliana prompted us to analyze the effect of non-synonymous SNPs (nsSNPs onto phosphorylation sites. Results From the analyses of 7,178 experimentally identified phosphorylation sites we found that: (i Proteins with multiple phosphorylation sites occur more often than expected by chance. (ii Phosphorylation hotspots show a preference to be located outside conserved domains. (iii nsSNPs affected experimental phosphorylation sites as much as the corresponding non-phosphorylated amino acid residues. (iv Losses of experimental phosphorylation sites by nsSNPs were identified in 86 A. thaliana proteins, among them receptor proteins were overrepresented. These results were confirmed by similar analyses of predicted phosphorylation sites in A. thaliana. In addition, predicted threonine phosphorylation sites showed a significant enrichment of nsSNPs towards asparagines and a significant depletion of the synonymous substitution. Proteins in which predicted phosphorylation sites were affected by nsSNPs (loss and gain, were determined to be mainly receptor proteins, stress response proteins and proteins involved in nucleotide and protein binding. Proteins involved in metabolism, catalytic activity and biosynthesis were less affected. Conclusions We analyzed more than 7,100 experimentally identified phosphorylation sites in almost 4,300 protein

  9. Cortical microtubule patterning in roots of Arabidopsis thaliana primary cell wall mutants reveals the bidirectional interplay with cell expansion.

    Science.gov (United States)

    Panteris, Emmanuel; Adamakis, Ioannis-Dimosthenis S; Daras, Gerasimos; Rigas, Stamatis

    2015-01-01

    Cell elongation requires directional deposition of cellulose microfibrils regulated by transverse cortical microtubules. Microtubules respond differentially to suppression of cell elongation along the developmental zones of Arabidopsis thaliana root apex. Cortical microtubule orientation is particularly affected in the fast elongation zone but not in the meristematic or transition zones of thanatos and pom2-4 cellulose-deficient mutants of Arabidopsis thaliana. Here, we report that a uniform phenotype is established among the primary cell wall mutants, as cortical microtubules of root epidermal cells of rsw1 and prc1 mutants exhibit the same pattern described in thanatos and pom2-4. Whether cortical microtubules assume transverse orientation or not is determined by the demand for cellulose synthesis, according to each root zone's expansion rate. It is suggested that cessation of cell expansion may provide a biophysical signal resulting in microtubule reorientation. PMID:26042727

  10. 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

  11. The TORNADO1 and TORNADO2 genes function in several patterning processes during early leaf development in Arabidopsis thaliana

    OpenAIRE

    Cnops, Gerda; Neyt, Pia; Raes, Jeroen; Petrarulo, Marica; Nelissen, Hilde; Malenica, Nenad; Luschnig, Christian; Tietz, Olaf; Ditengou, Franck; Palme, Klaus; Azmi, Abdelkrim; Prinsen, Els; Van Lijsebettens, Maria

    2006-01-01

    In multicellular organisms, patterning is a process that generates axes in the primary body plan, creates domains upon organ formation, and finally leads to differentiation into tissues and cell types. We identified the Arabidopsis thaliana TORNADO1 (TRN1) and TRN2 genes and their role in leaf patterning processes such as lamina venation, symmetry, and lateral growth. In trn mutants, the leaf venation network had a severely reduced complexity: incomplete loops, no tertiary or quaternary veins...

  12. Genetic and environmental control of the Verticillium syndrome in Arabidopsis thaliana

    OpenAIRE

    Diederichsen Elke; Karlovsky Petr; Häffner Eva

    2010-01-01

    Abstract Background Verticillium spp. are major pathogens of dicotyledonous plants such as cotton, tomato, olive or oilseed rape. Verticillium symptoms are often ambiguous and influenced by development and environment. The aim of the present study was to define disease and resistance traits of the complex Verticillium longisporum syndrome in Arabidopsis thaliana (L.) Heynh. A genetic approach was used to determine genetic, developmental and environmental factors controlling specific disease a...

  13. Targeting of the polyhydroxybutyrate biosynthetic pathway to the plastids of Arabidopsis thaliana results in high levels of polymer accumulation.

    OpenAIRE

    Nawrath, C; Poirier, Y; Somerville, C

    1994-01-01

    In the bacterium Alcaligenes eutrophus, three genes encode the enzymes necessary to catalyze the synthesis of poly[(R)-(-)-3-hydroxybutyrate] (PHB) from acetyl-CoA. In order to target these enzymes into the plastids of higher plants, the genes were modified by addition of DNA fragments encoding a pea chloroplast transit peptide, a constitutive plant promoter, and a poly(A) addition sequence. Each of the modified bacterial genes was introduced into Arabidopsis thaliana by Agrobacterium-mediate...

  14. Enzymatic characterization of a glycoside hydrolase family 5 subfamily 7 (GH5_7) mannanase from Arabidopsis thaliana

    OpenAIRE

    Wang, Yang; Vilaplana, Francisco; Brumer, Harry; Aspeborg, Henrik

    2013-01-01

    Each plant genome contains a repertoire of β-mannanase genes belonging to glycoside hydrolase family 5 subfamily 7 (GH5_7), putatively involved in the degradation and modification of various plant mannan polysaccharides, but very few have been characterized at the gene product level. The current study presents recombinant production and in vitro characterization of AtMan5-1 as a first step towards the exploration of the catalytic capacity of Arabidopsis thaliana β-mannanase. The target enzyme...

  15. Belowground neighbor perception in Arabidopsis thaliana studied by transcriptome analysis: roots of Hieracium pilosella cause biotic stress

    OpenAIRE

    Schmid, Christoph; Bauer, Sibylle; Müller, Benedikt; Bartelheimer, Maik

    2013-01-01

    Root-root interactions are much more sophisticated than previously thought, yet the mechanisms of belowground neighbor perception remain largely obscure. Genome-wide transcriptome analyses allow detailed insight into plant reactions to environmental cues. A root interaction trial was set up to explore both morphological and whole genome transcriptional responses in roots of Arabidopsis thaliana in the presence or absence of an inferior competitor, Hieracium pilosella. Neighbor perception was ...

  16. Loss of membrane fluidity and endocytosis inhibition are involved in rapid aluminum-induced root growth cessation in Arabidopsis thaliana

    Czech Academy of Sciences Publication Activity Database

    Krtková, J.; Havelková, L.; Křepelová, A.; Fišer, R.; Vosolsobě, S.; Novotná, Z.; Martinec, Jan; Schwarzerová, K.

    2012-01-01

    Roč. 60, Nov 2012 (2012), s. 88-97. ISSN 0981-9428 R&D Projects: GA ČR GA522/05/0340 Grant ostatní: GA ČR(CZ) GPP207/12/P890 Institutional research plan: CEZ:AV0Z50380511 Keywords : Aluminum toxicity * Arabidopsis thaliana * Cortical microtubules Subject RIV: ED - Physiology Impact factor: 2.775, year: 2012

  17. Response of Arabidopsis thaliana Roots with Altered Lipid Transfer Protein (LTP) Gene Expression to the Clubroot Disease and Salt Stress

    OpenAIRE

    Sabine Jülke; Jutta Ludwig-Müller

    2015-01-01

    The clubroot disease of Brassicaceae is caused by the obligate biotrophic protist Plasmodiophora brassicae. The disease is characterized by abnormal tumorous swellings of infected roots that result in reduced drought resistance and insufficient distribution of nutrients, leading to reduced crop yield. It is one of the most damaging diseases among cruciferous crops worldwide. The acquisition of nutrients by the protist is not well understood. Gene expression profiles in Arabidopsis thaliana cl...

  18. A Kinetic Analysis of Regiospecific Glucosylation by Two Glycosyltransferases of Arabidopsis thaliana: DOMAIN SWAPPING TO INTRODUCE NEW ACTIVITIES*S⃞

    OpenAIRE

    Cartwright, Adam M.; Lim, Eng-Kiat; Kleanthous, Colin; Bowles, Dianna J

    2008-01-01

    Plant Family 1 glycosyltransferases (GTs) recognize a wide range of natural and non-natural scaffolds and have considerable potential as biocatalysts for the synthesis of small molecule glycosides. Regiospecificity of glycosylation is an important property, given that many acceptors have multiple potential glycosylation sites. This study has used a domain-swapping approach to explore the determinants of regiospecific glycosylation of two GTs of Arabidopsis thaliana, UG...

  19. The Saharan isolate Saccharothrix algeriensis NRRL B-24137 induces systemic resistance in Arabidopsis thaliana seedlings against Botrytis cinerea

    OpenAIRE

    Muzammil, Saima; Graillon, Clotilde; Saria, Rayenne; Mathieu, Florence; Lebrihi, Ahmed; Compant, Stéphane

    2013-01-01

    Background and aim Saccharothrix algeriensis NRRL B-24137, isolated from a Saharan soil, has been described as a potential biocontrol agent against Botrytis cinerea and other phytopathogens. However, the plant protection mechanisms involved still need to be described. The aim of this study was to determine this protection phenomenon as well as parts of the mechanisms involved, using Arabidopsis thaliana seedlings and B. cinerea. Methods The bacterial colonization process was evaluated on A. t...

  20. Selection of valine-resistance in callus culture of Arabidopsis thaliana (L.) Heynh. derived from leaf explants

    OpenAIRE

    Małgorzata D. Gaj; Grzegorz Czaja; Małgorzata Nawrot

    2014-01-01

    The selection of valine-resistant mutants was carried out in leaf explant cultures of three Arabidopsis thaliana (L.) Heynh. ecotypes: C-24, RLD and Columbia. The valine concentration used for in vitro selection, lethal for seed-growing plants, has not affected callus formation and growth. However, strong inhibition of shoot regeneration ability of calli growing under selection pressure was noticed. In total, 1043 explants were cultured on valine medium and 18 shoots were regenerated with an ...

  1. Ectopic expression of Jatropha curcas APETALA1 (JcAP1) caused early flowering in Arabidopsis, but not in Jatropha

    Science.gov (United States)

    Tang, Mingyong; Tao, Yan-Bin

    2016-01-01

    Jatropha curcas is a promising feedstock for biofuel production because Jatropha oil is highly suitable for the production of biodiesel and bio-jet fuels. However, Jatropha exhibits a low seed yield as a result of unreliable and poor flowering. APETALA1 (AP1) is a floral meristem and organ identity gene in higher plants. The flower meristem identity genes of Jatropha have not yet been identified or characterized. To better understand the genetic control of flowering in Jatropha, an AP1 homolog (JcAP1) was isolated from Jatropha. An amino acid sequence analysis of JcAP1 revealed a high similarity to the AP1 proteins of other perennial plants. JcAP1 was expressed in inflorescence buds, flower buds, sepals and petals. The highest expression level was observed during the early developmental stage of the flower buds. The overexpression of JcAP1 using the cauliflower mosaic virus (CaMV) 35S promoter resulted in extremely early flowering and abnormal flowers in transgenic Arabidopsis plants. Several flowering genes downstream of AP1 were up-regulated in the JcAP1-overexpressing transgenic plant lines. Furthermore, JcAP1 overexpression rescued the phenotype caused by the Arabidopsis AP1 loss-of-function mutant ap1-11. Therefore, JcAP1 is an ortholog of AtAP1, which plays a similar role in the regulation of flowering in Arabidopsis. However, the overexpression of JcAP1 in Jatropha using the same promoter resulted in little variation in the flowering time and floral organs, indicating that JcAP1 may be insufficient to regulate flowering by itself in Jatropha. This study helps to elucidate the function of JcAP1 and contributes to the understanding of the molecular mechanisms of flower development in Jatropha. PMID:27168978

  2. Ectopic expression of Jatropha curcas APETALA1 (JcAP1) caused early flowering in Arabidopsis, but not in Jatropha.

    Science.gov (United States)

    Tang, Mingyong; Tao, Yan-Bin; Xu, Zeng-Fu

    2016-01-01

    Jatropha curcas is a promising feedstock for biofuel production because Jatropha oil is highly suitable for the production of biodiesel and bio-jet fuels. However, Jatropha exhibits a low seed yield as a result of unreliable and poor flowering. APETALA1 (AP1) is a floral meristem and organ identity gene in higher plants. The flower meristem identity genes of Jatropha have not yet been identified or characterized. To better understand the genetic control of flowering in Jatropha, an AP1 homolog (JcAP1) was isolated from Jatropha. An amino acid sequence analysis of JcAP1 revealed a high similarity to the AP1 proteins of other perennial plants. JcAP1 was expressed in inflorescence buds, flower buds, sepals and petals. The highest expression level was observed during the early developmental stage of the flower buds. The overexpression of JcAP1 using the cauliflower mosaic virus (CaMV) 35S promoter resulted in extremely early flowering and abnormal flowers in transgenic Arabidopsis plants. Several flowering genes downstream of AP1 were up-regulated in the JcAP1-overexpressing transgenic plant lines. Furthermore, JcAP1 overexpression rescued the phenotype caused by the Arabidopsis AP1 loss-of-function mutant ap1-11. Therefore, JcAP1 is an ortholog of AtAP1, which plays a similar role in the regulation of flowering in Arabidopsis. However, the overexpression of JcAP1 in Jatropha using the same promoter resulted in little variation in the flowering time and floral organs, indicating that JcAP1 may be insufficient to regulate flowering by itself in Jatropha. This study helps to elucidate the function of JcAP1 and contributes to the understanding of the molecular mechanisms of flower development in Jatropha. PMID:27168978

  3. AtTHIC, a gene involved in thiamine biosynthesis in Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    Danyu Kong; Yuxing Zhu; Huilan Wu; Xudong Cheng; Hui Liang; Hong-Qing Ling

    2008-01-01

    Thiamine (vitamin B1) is an essential compound for organisms.It contains a pyrimidine ring structure and a thiazole ring structure.These two moieties of thiamine are synthesized independently and then coupled together.Here we report the molecular characterization of AtTHIC,which is involved in thiamine biosynthesis in Arabidopsis.AtTHIC is similar to Escherichia coil ThiC,which is involved in pyrimidine biosynthesis in prokaryotes.Heterologous expression of AtTHIC could functionally complement the thiC knock-out mutant of E.coll.Downregulation of AtTHIC expression by T-DNA insertion at its promoter region resulted in a drastic reduction of thiamine content in plants and the knock-down mutant thicl showed albino (white leaves) and lethal phenotypes under the normal culture conditions.The thicl mutant could be rescued by supplementation of thiamine and its defect functions could be complemented by expression ofAtTHIC cDNA.Transient expression analysis revealed that the AtTHIC protein targets plastids and chloroplasts.AtTHIC was strongly expressed in leaves,flowers and siliques and the transcription of AtTHIC was downregulated by extrinsic thiamine.In conclusion,AtTHIC is a gene involved in pyrimidine synthesis in the thiamine biosynthesis pathway of Arabidopsis,and our results provide some new clues for elucidating the pathway of thiamine biosynthesis in plants.

  4. SRK2C, a SNF1-related protein kinase 2, improves drought tolerance by controlling stress-responsive gene expression in Arabidopsis thaliana

    OpenAIRE

    Umezawa, Taishi; Yoshida, Riichiro; Maruyama, Kyonoshin; Yamaguchi-Shinozaki, Kazuko; Shinozaki, Kazuo

    2004-01-01

    Protein phosphorylation/dephosphorylation are major signaling events induced by osmotic stress in higher plants. Here, we showed that a SNF1-related protein kinase 2 (SnRK2), SRK2C, is an osmotic-stress-activated protein kinase in Arabidopsis thaliana that can significantly impact drought tolerance of Arabidopsis plants. Knockout mutants of SRK2C exhibited drought hypersensitivity in their roots, suggesting that SRK2C is a positive regulator of drought tolerance in Arabidopsis roots. Addition...

  5. Characterization of a new mutant allele of the Arabidopsis Flowering Locus D (FLD) gene that controls the flowering time by repressing FLC

    Institute of Scientific and Technical Information of China (English)

    CHEN Ruiqiang; ZHANG Suzhi; SUN Shulan; CHANG Jianhong; ZUO Jianru

    2005-01-01

    Flowering in higher plants is controlled by both the internal and environmental cues. In Arabidopsis, several major genetic loci have been defined as the key switches to control flowering. The Flowering Locus C (FLC) gene has been shown in the autonomous pathway to inhibit the vegetative-to-reproductive transition. FLC appears to be repressed by Flowering Locus D (FLD), which encodes a component of the histone deacetylase complex. Here we report the identification and characterization of a new mutant allele fld-5. Genetic analysis indicates that fld-5 (in the Wassilewskija background) is allelic to the previously characterized fld-3 and fld-4 (in the Colombia-0 background). Genetic and molecular analyses reveal that fld-5 carries a frame-shift mutation, resulting in a premature termination of the FLD open reading frame. The FLC expression is remarkably increased in fld-5, which presumably attributes to the extremely delayed flowering phenotype of the mutant.

  6. Arabidopsis thaliana GYRB3 does not encode a DNA gyrase subunit.

    Directory of Open Access Journals (Sweden)

    Katherine M Evans-Roberts

    Full Text Available DNA topoisomerases are enzymes that control the topology of DNA in all cells. DNA gyrase is unique among the topoisomerases in that it is the only enzyme that can actively supercoil DNA using the free energy of ATP hydrolysis. Until recently gyrase was thought to be unique to bacteria, but has now been discovered in plants. The genome of the model plant, Arabidopsis thaliana, is predicted to encode four gyrase subunits: AtGyrA, AtGyrB1, AtGyrB2 and AtGyrB3.We found, contrary to previous data, that AtGyrB3 is not essential to the survival of A. thaliana. Bioinformatic analysis suggests AtGyrB3 is considerably shorter than other gyrase B subunits, lacking part of the ATPase domain and other key motifs found in all type II topoisomerases; but it does contain a putative DNA-binding domain. Partially purified AtGyrB3 cannot bind E. coli GyrA or support supercoiling. AtGyrB3 cannot complement an E. coli gyrB temperature-sensitive strain, whereas AtGyrB2 can. Yeast two-hybrid analysis suggests that AtGyrB3 cannot bind to AtGyrA or form a dimer.These data strongly suggest that AtGyrB3 is not a gyrase subunit but has another unknown function. One possibility is that it is a nuclear protein with a role in meiosis in pollen.

  7. Arabidopsis thaliana GYRB3 Does Not Encode a DNA Gyrase Subunit

    Science.gov (United States)

    Evans-Roberts, Katherine M.; Breuer, Christian; Wall, Melisa K.; Sugimoto-Shirasu, Keiko; Maxwell, Anthony

    2010-01-01

    Background DNA topoisomerases are enzymes that control the topology of DNA in all cells. DNA gyrase is unique among the topoisomerases in that it is the only enzyme that can actively supercoil DNA using the free energy of ATP hydrolysis. Until recently gyrase was thought to be unique to bacteria, but has now been discovered in plants. The genome of the model plant, Arabidopsis thaliana, is predicted to encode four gyrase subunits: AtGyrA, AtGyrB1, AtGyrB2 and AtGyrB3. Methodology/Principal Findings We found, contrary to previous data, that AtGyrB3 is not essential to the survival of A. thaliana. Bioinformatic analysis suggests AtGyrB3 is considerably shorter than other gyrase B subunits, lacking part of the ATPase domain and other key motifs found in all type II topoisomerases; but it does contain a putative DNA-binding domain. Partially purified AtGyrB3 cannot bind E. coli GyrA or support supercoiling. AtGyrB3 cannot complement an E. coli gyrB temperature-sensitive strain, whereas AtGyrB2 can. Yeast two-hybrid analysis suggests that AtGyrB3 cannot bind to AtGyrA or form a dimer. Conclusions/Significance These data strongly suggest that AtGyrB3 is not a gyrase subunit but has another unknown function. One possibility is that it is a nuclear protein with a role in meiosis in pollen. PMID:20360860

  8. Phosphate relieves chromium toxicity in Arabidopsis thaliana plants by interfering with chromate uptake.

    Science.gov (United States)

    López-Bucio, José; Hernández-Madrigal, Fátima; Cervantes, Carlos; Ortiz-Castro, Randy; Carreón-Abud, Yazmín; Martínez-Trujillo, Miguel

    2014-04-01

    Soil contamination by hexavalent chromium [Cr(VI) or chromate] due to anthropogenic activities has become an increasingly important environmental problem. Mineral nutrients such as phosphate (Pi), sulfate and nitrate have been reported to attenuate Cr(VI) toxicity, but the underlying mechanisms remain to be clarified. Here, we show that chromate activates the expression of low-Pi inducible reporter genes AtPT1 and AtPT2 in Arabidopsis thaliana transgenic seedlings. Primary-root growth was inhibited by 60 % in AtPT2::uidA-expressing seedlings upon exposure to 140-μM Cr(VI). However, increasing the Pi and sulfate supply to the seedlings that were experiencing Cr(VI) toxicity completely and partially restored the root growth, respectively. This effect correlated with the Cr(VI)-induced AtPT2::uidA expression being completely reversed by addition of Pi. To evaluate whether the nutrient supply may affect the endogenous level of Cr in plants grown under toxic Cr(VI) levels, the contents of Cr were measured (by ICP-MS analyses) in seedlings treated with Cr and with or without Pi, sulfate or nitrate. It was found that Cr accumulation increases tenfold in plants treated with 140-μM Cr(VI) without modifying the phosphorus concentration in the plant. In contrast, the supply of Pi specifically decreased the Cr content to levels similar to those found in seedlings grown in medium without chromate. Taken together, these results show that in A. thaliana seedlings the uptake of Cr(VI) is reduced by Pi. Moreover, our data indicate that Pi and sulfate supplements may be useful in strategies for handling Cr-contaminated soils. PMID:24549595

  9. Cytonuclear interactions affect adaptive traits of the annual plant Arabidopsis thaliana in the field.

    Science.gov (United States)

    Roux, Fabrice; Mary-Huard, Tristan; Barillot, Elise; Wenes, Estelle; Botran, Lucy; Durand, Stéphanie; Villoutreix, Romain; Martin-Magniette, Marie-Laure; Camilleri, Christine; Budar, Françoise

    2016-03-29

    Although the contribution of cytonuclear interactions to plant fitness variation is relatively well documented at the interspecific level, the prevalence of cytonuclear interactions at the intraspecific level remains poorly investigated. In this study, we set up a field experiment to explore the range of effects that cytonuclear interactions have on fitness-related traits inArabidopsis thaliana To do so, we created a unique series of 56 cytolines resulting from cytoplasmic substitutions among eight natural accessions reflecting within-species genetic diversity. An assessment of these cytolines and their parental lines scored for 28 adaptive whole-organism phenotypes showed that a large proportion of phenotypic traits (23 of 28) were affected by cytonuclear interactions. The effects of these interactions varied from slight but frequent across cytolines to strong in some specific parental pairs. Two parental pairs accounted for half of the significant pairwise interactions. In one parental pair, Ct-1/Sha, we observed symmetrical phenotypic responses between the two nuclear backgrounds when combined with specific cytoplasms, suggesting nuclear differentiation at loci involved in cytonuclear epistasis. In contrast, asymmetrical phenotypic responses were observed in another parental pair, Cvi-0/Sha. In the Cvi-0 nuclear background, fecundity and phenology-related traits were strongly affected by the Sha cytoplasm, leading to a modified reproductive strategy without penalizing total seed production. These results indicate that natural variation in cytoplasmic and nuclear genomes interact to shape integrative traits that contribute to adaptation, thereby suggesting that cytonuclear interactions can play a major role in the evolutionary dynamics ofA. thaliana. PMID:26979961

  10. Finding missing interactions of the Arabidopsis thaliana root stem cell niche gene regulatory network

    Directory of Open Access Journals (Sweden)

    Eugenio eAzpeitia

    2013-04-01

    Full Text Available AbstractOver the last few decades, the Arabidopsis thaliana root stem cell niche has become a model system for the study of plant development and the stem cell niche. Currently, many of the molecular mechanisms involved in root stem cell niche maintenance and development have been described. A few years ago, we published a gene regulatory network model integrating this information. This model suggested that there were missing components or interactions. Upon updating the model, the observed stable gene configurations of the root stem cell niche could not be recovered, indicating that there are additional missing components or interactions in the model. In fact, due to the lack of experimental data, gene regulatory networks inferred from published data are usually incomplete. However, predicting the location and nature of the missing data is a not trivial task. Here, we propose a set of procedures for detecting and predicting missing interactions in Boolean networks. We used these procedures to predict putative missing interactions in the A. thaliana root stem cell niche network model. Using our approach, we identified three necessary interactions to recover the reported gene activation configurations that have been experimentally uncovered for the different cell types within the root stem cell niche: 1 a regulation of PHABULOSA to restrict its expression domain to the vascular cells, 2 a self-regulation of WOX5, possibly by an indirect mechanism through the auxin signalling pathway and 3 a positive regulation of JACKDAW by MAGPIE. The procedures proposed here greatly reduce the number of possible Boolean functions that are biologically meaningful and experimentally testable and that do not contradict previous data. We believe that these procedures can be used on any Boolean network. However, because the procedures were designed for the specific case of the root stem cell niche, formal demonstrations of the procedures should be shown in future

  11. Modulation of modeled microgravity on radiation-induced bystander effects in Arabidopsis thaliana

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ting [Key Laboratory of Ion Beam Bio-engineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031 (China); Sun, Qiao [Space Molecular Biological Lab, China Academy of Space Technology, Beijing 100086 (China); Xu, Wei; Li, Fanghua [Key Laboratory of Ion Beam Bio-engineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031 (China); Li, Huasheng; Lu, Jinying [Space Molecular Biological Lab, China Academy of Space Technology, Beijing 100086 (China); Wu, Lijun; Wu, Yuejin [Key Laboratory of Ion Beam Bio-engineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031 (China); Liu, Min [Space Molecular Biological Lab, China Academy of Space Technology, Beijing 100086 (China); Bian, Po [Key Laboratory of Ion Beam Bio-engineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031 (China)

    2015-03-15

    Highlights: • The effects of microgravity on the radiation-induced bystander effects (RIBE) were definitely demonstrated. • The effects of microgravity on RIBE might be divergent for different biological events. • The microgravity mainly modified the generation or transport of bystander signals at early stage. - Abstract: Both space radiation and microgravity have been demonstrated to have inevitable impact on living organisms during space flights and should be considered as important factors for estimating the potential health risk for astronauts. Therefore, the question whether radiation effects could be modulated by microgravity is an important aspect in such risk evaluation. Space particles at low dose and fluence rate, directly affect only a fraction of cells in the whole organism, which implement radiation-induced bystander effects (RIBE) in cellular response to space radiation exposure. The fact that all of the RIBE experiments are carried out in a normal gravity condition bring forward the need for evidence regarding the effect of microgravity on RIBE. In the present study, a two-dimensional rotation clinostat was adopted to demonstrate RIBE in microgravity conditions, in which the RIBE was assayed using an experimental system of root-localized irradiation of Arabidopsis thaliana (A. thaliana) plants. The results showed that the modeled microgravity inhibited significantly the RIBE-mediated up-regulation of expression of the AtRAD54 and AtRAD51 genes, generation of reactive oxygen species (ROS) and transcriptional activation of multicopy P35S:GUS, but made no difference to the induction of homologous recombination by RIBE, showing divergent responses of RIBE to the microgravity conditions. The time course of interaction between the modeled microgravity and RIBE was further investigated, and the results showed that the microgravity mainly modulated the processes of the generation or translocation of the bystander signal(s) in roots.

  12. Effects of elevated carbon dioxide and sucrose concentrations on Arabidopsis thaliana root architecture and anatomy

    Energy Technology Data Exchange (ETDEWEB)

    Lee-Ho, E.; Walton, L.J.; Reid, D.M.; Yeung, E.C.; Kurepin, L.V. [Calgary Univ., AB (Canada). Dept. of Biology

    2007-03-15

    Plant root growth is known to be influenced by higher levels of atmospheric carbon dioxide (CO{sub 2}). Roots of some species grown in hydroponics under elevated CO{sub 2} concentrations may be more competitive sinks for photosynthetic assimilates than roots grown under lower CO{sub 2} conditions. Root branching patterns may also be influenced by elevated CO{sub 2} concentrations. Studies have also shown that factors such as soil compaction, salinity and the availability of nitrate, phosphorous, oxygen and water also influence root growth, and the effects of higher CO{sub 2} on roots can be confounded by such environmental factors. This study evaluated the effects of elevated carbon dioxide and sucrose concentrations on Arabidopsis thaliana root growth, morphology, and architecture. Both ambient and elevated CO{sub 2} levels were used along with various sucrose concentrations. The study revealed that A. thaliana plants grown on a phytagar medium in small chambers with elevated CO{sub 2} had longer roots, more lateral root growth than plants grown in ambient CO{sub 2}. Roots in elevated CO{sub 2} were found to have wider root diameters, and more secondary growth. The addition of sucrose to the media closely resembled the effects of elevated CO{sub 2}. In addition, the increase in sucrose concentration had a bigger effect on root morphology under ambient, than elevated CO{sub 2}. Therefore, both elevated CO{sub 2} and increased sucrose concentrations promote root growth by increasing their number, length, and diameter. The dichotomy branching index (DBI) also dropped resulting in a more dichotomous branching pattern. 34 refs., 5 figs.

  13. Photorespiratory Bypasses Lead to Increased Growth in Arabidopsis thaliana: Are Predictions Consistent with Experimental Evidence?

    Science.gov (United States)

    Basler, Georg; Küken, Anika; Fernie, Alisdair R; Nikoloski, Zoran

    2016-01-01

    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 A. thaliana. In addition, we investigate three scenarios with respect to experimental findings on the ratios of the carboxylation and oxygenation reactions of Ribulose-1,5-bisphosphate carboxylase/oxygenase (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 co-factor 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. PMID:27092301

  14. Pollen-Specific Aquaporins NIP4;1 and NIP4;2 Are Required for Pollen Development and Pollination in Arabidopsis thaliana.

    Science.gov (United States)

    Di Giorgio, Juliana Andrea Pérez; Bienert, Gerd Patrick; Ayub, Nicolás Daniel; Yaneff, Agustín; Barberini, María Laura; Mecchia, Martín Alejandro; Amodeo, Gabriela; Soto, Gabriela Cynthia; Muschietti, Jorge Prometeo

    2016-05-01

    In flowers with dry stigmas, pollen development, pollination, and pollen tube growth require spatial and temporal regulation of water and nutrient transport. To better understand the molecular mechanisms involved in reproductive processes, we characterized NIP4;1 and NIP4;2, two pollen-specific aquaporins of Arabidopsis thaliana. NIP4;1 and NIP4;2 are paralogs found exclusively in the angiosperm lineage. Although they have 84% amino acid identity, they displayed different expression patterns. NIP4;1 has low expression levels in mature pollen, while NIP4;2 expression peaks during pollen tube growth. Additionally, NIP4;1pro:GUS flowers showed GUS activity in mature pollen and pollen tubes, whereas NIP4;2pro:GUS flowers only in pollen tubes. Single T-DNA mutants and double artificial microRNA knockdowns had fewer seeds per silique and reduced pollen germination and pollen tube length. Transport assays in oocytes showed NIP4;1 and NIP4;2 function as water and nonionic channels. We also found that NIP4;1 and NIP4;2 C termini are phosphorylated by a pollen-specific CPK that modifies their water permeability. Survival assays in yeast indicated that NIP4;1 also transports ammonia, urea, boric acid, and H2O2 Thus, we propose that aquaporins NIP4;1 and NIP4;2 are exclusive components of the reproductive apparatus of angiosperms with partially redundant roles in pollen development and pollination. PMID:27095837

  15. Defects in Peroxisomal 6-Phosphogluconate Dehydrogenase Isoform PGD2 Prevent Gametophytic Interaction in Arabidopsis thaliana.

    Science.gov (United States)

    Hölscher, Christian; Lutterbey, Marie-Christin; Lansing, Hannes; Meyer, Tanja; Fischer, Kerstin; von Schaewen, Antje

    2016-05-01

    We studied the localization of 6-phosphogluconate dehydrogenase (PGD) isoforms of Arabidopsis (Arabidopsis thaliana). Similar polypeptide lengths of PGD1, PGD2, and PGD3 obscured which isoform may represent the cytosolic and/or plastidic enzyme plus whether PGD2 with a peroxisomal targeting motif also might target plastids. Reporter-fusion analyses in protoplasts revealed that, with a free N terminus, PGD1 and PGD3 accumulate in the cytosol and chloroplasts, whereas PGD2 remains in the cytosol. Mutagenesis of a conserved second ATG enhanced the plastidic localization of PGD1 and PGD3 but not PGD2. Amino-terminal deletions of PGD2 fusions with a free C terminus resulted in peroxisomal import after dimerization, and PGD2 could be immunodetected in purified peroxisomes. Repeated selfing of pgd2 transfer (T-)DNA alleles yielded no homozygous mutants, although siliques and seeds of heterozygous plants developed normally. Detailed analyses of the C-terminally truncated PGD2-1 protein showed that peroxisomal import and catalytic activity are abolished. Reciprocal backcrosses of pgd2-1 suggested that missing PGD activity in peroxisomes primarily affects the male gametophyte. Tetrad analyses in the quartet1-2 background revealed that pgd2-1 pollen is vital and in vitro germination normal, but pollen tube growth inside stylar tissues appeared less directed. Mutual gametophytic sterility was overcome by complementation with a genomic construct but not with a version lacking the first ATG. These analyses showed that peroxisomal PGD2 activity is required for guided growth of the male gametophytes and pollen tube-ovule interaction. Our report finally demonstrates an essential role of oxidative pentose-phosphate pathway reactions in peroxisomes, likely needed to sustain critical levels of nitric oxide and/or jasmonic acid, whose biosynthesis both depend on NADPH provision. PMID:26941195

  16. Effects of aneuploidy on genome structure, expression, and interphase organization in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Bruno Huettel

    2008-10-01

    Full Text Available Aneuploidy refers to losses and/or gains of individual chromosomes from the normal chromosome set. The resulting gene dosage imbalance has a noticeable affect on the phenotype, as illustrated by aneuploid syndromes, including Down syndrome in humans, and by human solid tumor cells, which are highly aneuploid. Although the phenotypic manifestations of aneuploidy are usually apparent, information about the underlying alterations in structure, expression, and interphase organization of unbalanced chromosome sets is still sparse. Plants generally tolerate aneuploidy better than animals, and, through colchicine treatment and breeding strategies, it is possible to obtain inbred sibling plants with different numbers of chromosomes. This possibility, combined with the genetic and genomics tools available for Arabidopsis thaliana, provides a powerful means to assess systematically the molecular and cytological consequences of aberrant numbers of specific chromosomes. Here, we report on the generation of Arabidopsis plants in which chromosome 5 is present in triplicate. We compare the global transcript profiles of normal diploids and chromosome 5 trisomics, and assess genome integrity using array comparative genome hybridization. We use live cell imaging to determine the interphase 3D arrangement of transgene-encoded fluorescent tags on chromosome 5 in trisomic and triploid plants. The results indicate that trisomy 5 disrupts gene expression throughout the genome and supports the production and/or retention of truncated copies of chromosome 5. Although trisomy 5 does not grossly distort the interphase arrangement of fluorescent-tagged sites on chromosome 5, it may somewhat enhance associations between transgene alleles. Our analysis reveals the complex genomic changes that can occur in aneuploids and underscores the importance of using multiple experimental approaches to investigate how chromosome numerical changes condition abnormal phenotypes and

  17. Effect of magnetic fields on cryptochrome-dependent responses in Arabidopsis thaliana

    Science.gov (United States)

    Harris, Sue-Re; Henbest, Kevin B.; Maeda, Kiminori; Pannell, John R.; Timmel, Christiane R.; Hore, P.J.; Okamoto, Haruko

    2009-01-01

    The scientific literature describing the effects of weak magnetic fields on living systems contains a plethora of contradictory reports, few successful independent replication studies and a dearth of plausible biophysical interaction mechanisms. Most such investigations have been unsystematic, devoid of testable theoretical predictions and, ultimately, unconvincing. A recent study, of magnetic responses in the model plant Arabidopsis thaliana, however, stands out; it has a clear hypothesis—that seedling growth is magnetically sensitive as a result of photoinduced radical-pair reactions in cryptochrome photoreceptors—tested by measuring several cryptochrome-dependent responses, all of which proved to be enhanced in a magnetic field of intensity 500 μT. The potential importance of this study in the debate on putative effects of extremely low-frequency electromagnetic fields on human health prompted us to subject it to the ‘gold standard’ of independent replication. With experimental conditions chosen to match those of the original study, we have measured hypocotyl lengths and anthocyanin accumulation for Arabidopsis seedlings grown in a 500 μT magnetic field, with simultaneous control experiments at 50 μT. Additionally, we have determined hypocotyl lengths of plants grown in 50 μT, 1 mT and approximately 100 mT magnetic fields (with zero-field controls), measured gene (CHS, HY5 and GST) expression levels, investigated blue-light intensity effects and explored the influence of sucrose in the growth medium. In no case were consistent, statistically significant magnetic field responses detected. PMID:19324677

  18. UGT74D1 is a novel auxin glycosyltransferase from Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Shang-Hui Jin

    Full Text Available Auxin is one type of phytohormones that plays important roles in nearly all aspects of plant growth and developmental processes. The glycosylation of auxins is considered to be an essential mechanism to control the level of active auxins. Thus, the identification of auxin glycosyltransferases is of great significance for further understanding the auxin regulation. In this study, we biochemically screened the group L of Arabidopsis thaliana glycosyltransferase superfamily for enzymatic activity toward auxins. UGT74D1 was identified to be a novel auxin glycosyltransferase. Through HPLC and LC-MS analysis of reaction products in vitro by testing eight substrates including auxins and other compounds, we found that UGT74D1 had a strong glucosylating activity toward indole-3-butyric acid [IBA], indole-3-propionic acid [IPA], indole-3-acetic acid [IAA] and naphthaleneacetic acid [NAA], catalyzing them to form corresponding glucose esters. Biochemical characterization showed that this enzyme had a maximum activity in HEPES buffer at pH 6.0 and 37°C. In addition, the enzymatic activity analysis of crude protein and the IBA metabolite analysis from transgenic Arabidopsis plants overexpressing UGT74D1 gene were also carried out. Experimental results indicated that over-production of the UGT74D1 in plants indeed led to increased level of the glucose conjugate of IBA. Moreover, UGT74D1 overexpression lines displayed curling leaf phenotype, suggesting a physiological role of UGT74D1 in affecting the activity of auxins. Our current data provide a new target gene for further genetic studies to understand the auxin regulation by glycosylation in plants.

  19. DRB2 is required for microRNA biogenesis in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    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.

  20. Calcium-Dependent Protein Kinase CPK21 Functions in Abiotic Stress Response in Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    Sandra Franz; Britta Ehlert; Anja Liese; Joachim Kurth; Anne-Claire Cazalé; Tina Romeis

    2011-01-01

    Calcium-dependent protein kinases(CDPKs)comprise a family of plant serine/threonine protein kinases in which the calcium sensing domain and the kinase effector domain are combined within one molecule.So far,a biological function in abiotic stress signaling has only been reported for few CDPK isoforms,whereas the underlying biochemical mechanism for these CDPKs is still mainly unknown.Here,we show that CPK21 from Arabidopsis thaliana is biochemically activated in vivo in response to hyperosmotic stress.Loss-of-function seedlings of cpk21 are more tolerant to hyperosmotic stress and mutant plants show increased stress responses with respect to marker gene expression and metabolite accumulation.In transgenic Arabidopsis complementation lines in the cpk21 mutant background,in which either CPK21 wildtype,or a full-length enzyme variant carrying an amino-acid substitution were stably expressed,stress responsitivity was restored by CPK21 but not with the kinase inactive variant.The biochemical characterization of in planta synthesized and purified CPK21 protein revealed that within the calcium-binding domain,N-terminal EF1- and EF2-motifs compared to C-terminal EF3- and EF4-motifs differ in their contribution to calcium-regulated kinase activity,suggesting a crucial role for the N-terminal EF-hand pair.Our data provide evidence for CPK21 contributing in abiotic stress signaling and suggest that the N-terminal EF-hand pair is a calcium-sensing determinant controlling specificity of CPK21 function.

  1. Variation in selenium tolerance and accumulation among 19 Arabidopsis thaliana accessions.

    Science.gov (United States)

    Zhang, Lihong; Ackley, Ashley R; Pilon-Smits, Elizabeth A H

    2007-03-01

    Selenium (Se) is an essential element for many organisms but also toxic at higher levels. The objective of this study was to identify accessions from the model species Arabidopsis thaliana that differ in Se tolerance and accumulation. Nineteen Arabidopsis accessions were grown from seed on agar medium with or without selenate (50 microM) or selenite (20 microM), followed by analysis of Se tolerance and accumulation. Tissue sulfur levels were also compared. The Se Tolerance Index (root length+Se/root length control) varied among the accessions from 0.11 to 0.44 for selenite and from 0.05 to 0.24 for selenate. When treated with selenite, the accessions differed by two-fold in shoot Se concentration (up to 250 mgkg(-1)) and three-fold in root Se concentration (up to 1000 mgkg(-1)). Selenium accumulation from selenate varied 1.7-fold in shoot (up to 1000 mgkg(-1)) and two-fold in root (up to 650 mgkg(-1)). Across all accessions, a strong correlation was observed between Se and S concentration in both shoot and root under selenate treatment, and in roots of selenite-treated plants. Shoot Se accumulation from selenate and selenite were also correlated. There was no correlation between Se tolerance and accumulation, either for selenate or selenite. The F(1) offspring from a cross between the extreme selenate-sensitive Dijon G and the extreme selenate-tolerant Estland accessions showed intermediate selenate tolerance. In contrast, the F(1) offspring from a cross between selenite-sensitive and -tolerant accessions (Dijon GxCol-PRL) were selenite tolerant. The results from this study give new insight into the mechanisms of plant selenium (Se) tolerance and accumulation, which may help develop better plants for selenium phytoremediation or as fortified foods. PMID:16513208

  2. YUCCA6 over-expression demonstrates auxin function in delaying leaf senescence in Arabidopsis thaliana

    KAUST Repository

    Kim, Jeong Im

    2011-04-21

    The Arabidopsis thaliana YUCCA family of flavin monooxygenase proteins catalyses a rate-limiting step in de novo auxin biosynthesis. A YUCCA6 activation mutant, yuc6-1D, has been shown to contain an elevated free IAA level and to display typical high-auxin phenotypes. It is reported here that Arabidopsis plants over-expressing YUCCA6, such as the yuc6-1D activation mutant and 35S:YUC6 transgenic plants, displayed dramatic longevity. In addition, plants over-expressing YUCCA6 exhibited classical, delayed dark-induced and hormone-induced senescence in assays using detached rosette leaves. However, plants over-expressing an allele of YUCCA6, that carries mutations in the NADPH cofactor binding site, exhibited neither delayed leaf senescence phenotypes nor phenotypes typical of auxin overproduction. When the level of free IAA was reduced in yuc6-1D by conjugation to lysine, yuc6-1D leaves senesced at a rate similar to the wild-type leaves. Dark-induced senescence in detached leaves was accompanied by a decrease in their free IAA content, by the reduced expression of auxin biosynthesis enzymes such as YUCCA1 and YUCCA6 that increase cellular free IAA levels, and by the increased expression of auxin-conjugating enzymes encoded by the GH3 genes that reduce the cellular free auxin levels. Reduced transcript abundances of SAG12, NAC1, and NAC6 during senescence in yuc6-1D compared with the wild type suggested that auxin delays senescence by directly or indirectly regulating the expression of senescence-associated genes. 2011 The Author(s).

  3. Conserved Functions of Arabidopsis and Rice CC-Type Glutaredoxins in Flower Development and Pathogen Response

    Institute of Scientific and Technical Information of China (English)

    Zhen Wang; Shuping Xing; Rainer P. Birkenbihl; Sabine Zachgo

    2009-01-01

    Glutaredoxins (GRXs) are ubiquitous oxidoreductases that play a crucial role in response to oxidative stress by reducing disulfides in various organisms. In planta, three different GRX classes have been identified according to their active site motifs. CPYC and CGFS classes are found in all organisms, whereas the CC-type class is specific for higher land plants. Recently, two Arabidopsis CC-type GRXs, ROXY1 and ROXY2, were shown to exert crucial functions in petal and anther initiation and differentiation. To analyze the function of CC-type GRXs in the distantly related monocots, we iso-lated and characterized OsROXY1 and OsROXY2-two rice homologs of ROXY1. Both genes are expressed in vegetative and reproductive stages. Although rice flower morphology is distinct from eudicots, OsROXY1/2 floral expression patterns are similar to their Arabidopsis counterparts ROXY1/2. Complementation experiments demonstrate that OsROXY1 and OsROXY2 can fully rescue the roxy1 floral mutant phenotype. Overexpression of OsROXY1, OsROXY2, and ROXY1 in Ara-bidopsis causes similar vegetative and reproductive plant developmental defects. ROXY1 and its rice homologs thus exert a conserved function during eudicot and monocot flower development. Strikingly, overexpression of these CC-type GRXs also leads to an increased accumulation of hydrogen peroxide levels and hyper-susceptibility to infection from the necrotrophic pathogen Botrytis cinerea, revealing the importance of balanced redox processes in flower organ develop-ment and pathogen defence.

  4. AthaMap-assisted transcription factor target gene identification in Arabidopsis thaliana.

    Science.gov (United States)

    Bülow, Lorenz; Brill, Yuri; Hehl, Reinhard

    2010-01-01

    The AthaMap database generates a map of potential transcription factor binding sites (TFBS) and small RNA target sites in the Arabidopsis thaliana genome. The database contains sites for 115 different transcription factors (TFs). TFBS were identified with positional weight matrices (PWMs) or with single binding sites. With the new web tool 'Gene Identification', it is possible to identify potential target genes for selected TFs. For these analyses, the user can define a region of interest of up to 6000 bp in all annotated genes. For TFBS determined with PWMs, the search can be restricted to high-quality TFBS. The results are displayed in tables that identify the gene, position of the TFBS and, if applicable, individual score of the TFBS. In addition, data files can be downloaded that harbour positional information of TFBS of all TFs in a region between -2000 and +2000 bp relative to the transcription or translation start site. Also, data content of AthaMap was increased and the database was updated to the TAIR8 genome release. Database URL: http://www.athamap.de/gene_ident.php. PMID:21177332

  5. Variable-angle total internal reflection fluorescence microscopy of intact cells of Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Kim Myung K

    2011-09-01

    Full Text Available Abstract Background Total internal reflection fluorescence microscopy (TIRFM is a powerful tool for observing fluorescently labeled molecules on the plasma membrane surface of animal cells. However, the utility of TIRFM in plant cell studies has been limited by the fact that plants have cell walls, thick peripheral layers surrounding the plasma membrane. Recently, a new technique known as variable-angle epifluorescence microscopy (VAEM was developed to circumvent this problem. However, the lack of a detailed analysis of the optical principles underlying VAEM has limited its applications in plant-cell biology. Results Here, we present theoretical and experimental evidence supporting the use of variable-angle TIRFM in observations of intact plant cells. We show that when total internal reflection occurs at the cell wall/cytosol interface with an appropriate angle of incidence, an evanescent wave field of constant depth is produced inside the cytosol. Results of experimental TIRFM observations of the dynamic behaviors of phototropin 1 (a membrane receptor protein and clathrin light chain (a vesicle coat protein support our theoretical analysis. Conclusions These findings demonstrate that variable-angle TIRFM is appropriate for quantitative live imaging of cells in intact tissues of Arabidopsis thaliana.

  6. A geographic cline in leaf salicylic acid with increasing elevation in Arabidopsis thaliana.

    Science.gov (United States)

    Zhang, Nana; Tonsor, Stephen J; Traw, M Brian

    2015-01-01

    Salicylic acid (SA) occupies a key role as a hormone central to both plant resistance to bacterial pathogens and tolerance of abiotic stresses. Plants at high elevation experience colder temperatures and elevated UV levels. While it has been predicted that SA concentrations will be higher in plants from high elevation populations, few studies have addressed this question. Here, we asked how concentrations of SA vary in natural populations of Arabidopsis thaliana collected across an elevational gradient on the Iberian Peninsula. In a series of common garden experiments, we found that constitutive SA concentrations were highest in genotypes from the low elevation populations. This result was in the opposite direction from our prediction and is an exception to the general finding that phenolic compounds increase with increasing elevation. These data suggest that high constitutive SA is not associated with resistance to cold temperatures in these plants. Furthermore, we also found that leaf constitutive camalexin concentrations, an important defense against some bacterial and fungal enemies, were highest in the low elevation populations, suggesting that pathogen pressures may be important. Further examination of this elevational cline will likely provide additional insights into the interplay between phenolic compounds and biotic and abiotic stress. PMID:25875692

  7. Cadmium localization and quantification in the plant Arabidopsis thaliana using micro-PIXE

    Science.gov (United States)

    Ager, F. J.; Ynsa, M. D.; Domínguez-Solís, J. R.; Gotor, C.; Respaldiza, M. A.; Romero, L. C.

    2002-04-01

    Remediation of metal-contaminated soils and waters poses a challenging problem due to its implications in the environment and the human health. The use of metal-accumulating plants to remove toxic metals, including Cd, from soil and aqueous streams has been proposed as a possible solution to this problem. The process of using plants for environmental restoration is termed phytoremediation. Cd is a particularly favourable target metal for this technology because it is readily transported and accumulated in the shoots of several plant species. This paper investigates the sites of metal localization within Arabidopsis thaliana leaves, when plants are grown in a cadmium-rich environment, by making use of nuclear microscopy techniques. Micro-PIXE, RBS and SEM analyses were performed on the scanning proton microprobe at the CNA in Seville (Spain), showing that cadmium is sequestered within the trichomes on the leaf surface. Additionally, regular PIXE analyses were performed on samples prepared by an acid digestion method in order to assess the metal accumulation of such plants.

  8. Cadmium localization and quantification in the plant Arabidopsis thaliana using micro-PIXE

    International Nuclear Information System (INIS)

    Remediation of metal-contaminated soils and waters poses a challenging problem due to its implications in the environment and the human health. The use of metal-accumulating plants to remove toxic metals, including Cd, from soil and aqueous streams has been proposed as a possible solution to this problem. The process of using plants for environmental restoration is termed phytoremediation. Cd is a particularly favourable target metal for this technology because it is readily transported and accumulated in the shoots of several plant species. This paper investigates the sites of metal localization within Arabidopsis thaliana leaves, when plants are grown in a cadmium-rich environment, by making use of nuclear microscopy techniques. Micro-PIXE, RBS and SEM analyses were performed on the scanning proton microprobe at the CNA in Seville (Spain), showing that cadmium is sequestered within the trichomes on the leaf surface. Additionally, regular PIXE analyses were performed on samples prepared by an acid digestion method in order to assess the metal accumulation of such plants

  9. Genome-Wide Search for Translated Upstream Open Reading Frames in Arabidopsis Thaliana.

    Science.gov (United States)

    Hu, Qiwen; Merchante, Catharina; Stepanova, Anna N; Alonso, Jose M; Heber, Steffen

    2016-03-01

    Upstream open reading frames (uORFs) are open reading frames that occur within the 5' UTR of an mRNA. uORFs have been found in many organisms. They play an important role in gene regulation, cell development, and in various metabolic processes. It is believed that translated uORFs reduce the translational efficiency of the main coding region. However, only few uORFs are experimentally characterized. In this paper, we use ribosome footprinting together with a semi-supervised approach based on stacking classification models to identify translated uORFs in Arabidopsis thaliana. Our approach identified 5360 potentially translated uORFs in 2051 genes. GO terms enriched in genes with translated uORFs include catalytic activity, binding, transferase activity, phosphotransferase activity, kinase activity, and transcription regulator activity. The reported uORFs occur with a higher frequency in multi-isoform genes, and some uORFs are affected by alternative transcript start sites or alternative splicing events. Association rule mining revealed sequence features associated with the translation status of the uORFs. We hypothesize that uORF translation is a complex process that might be regulated by multiple factors. The identified uORFs are available online at:https://www.dropbox.com/sh/zdutupedxafhly8/AABFsdNR5zDfiozB7B4igFcja?dl=0. This paper is the extended version of our research presented at ISBRA 2015. PMID:26886998

  10. Inflorescences contribute more than rosettes to lifetime carbon gain in Arabidopsis thaliana (Brassicaceae).

    Science.gov (United States)

    Earley, Eric J; Ingland, Bronson; Winkler, Jacob; Tonsor, Stephen J

    2009-04-01

    A metamorphosis from rosette to inflorescence in many annuals shifts photosynthetic tissue from a two-dimensional array in the soil boundary layer during cool months to a three-dimensional structure in the troposphere as spring progresses. We propose that this shift allows escape from both self-shading and an increasingly stressful boundary layer microclimate, permitting continued increases in growth. As a first step in exploring this hypothesis, we compared the lifetime C gain, water loss, and instantaneous water use efficiency (WUE) of five Arabidopsis thaliana genotypes by measuring gas exchange across the life cycle. On average, the inflorescence contributed 55% (± 5% SE) of lifetime C gain, but only 25% of lifetime water loss. Mean inflorescence WUE was nearly fourfold that of the rosette. The inflorescence continued to fix C after rosette senescence. The percentage inflorescence: total C gain varied among genotypes, from 36% to 93%. Genotypes differed in WUE for both structures. We suggest that local climates may have selected for divergence in these traits. For many annuals and winter annuals, understanding C and water budgets and their evolution must include measures of both rosette and inflorescence gas exchange. PMID:21628233

  11. Effects of microgravity and clinorotation on stress ethylene production in two starchless mutants of Arabidopsis thaliana

    Science.gov (United States)

    Gallegos, Gregory L.; Hilaire, Emmanuel M.; Peterson, Barbara V.; Brown, Christopher S.; Guikema, James A.

    1995-01-01

    Starch filled plastids termed amyloplasts, contained within columella cells of the root caps of higher plant roots, are believed to play a statolith-like role in the gravitropic response of roots. Plants having amyloplasts containing less starch exhibit a corresponding reduction in gravitropic response. We have observed enhanced ethylene production by sweet clover (Melilotus alba L.) seedlings grown in the altered gravity condition of a slow rotating clinostat, and have suggested that this is a stress response resulting from continuous gravistimulation rather than as a result of the simulation of a microgravity condition. If so, we expect that plants deficient in starch accumulation in amyloplasts may produce less stress ethylene when grown on a clinostat. Therefore, we have grown Arabidopsis thaliana in the small, closed environment of the Fluid Processing Apparatus (FPA). In this preliminary report we compare stationary plants with clinorotated and those grown in microgravity aboard Discovery during the STS-63 flight in February 1995. In addition to wildtype, two mutants deficient in starch biosynthesis, mutants TC7 and TL25, which are, respectively, deficient in the activity of amyloplast phosphoglucomutase and ADP-glucose pyrophosphorylase, were grown for three days before being fixed within the FPA. Gas samples were aspirated from the growth chambers and carbon dioxide and ethylene concentations were measured using a gas chromatograph. The fixed tissue is currently undergoing further morphologic and microscopic characterization.

  12. Cell-free translation and purification of Arabidopsis thaliana regulator of G signaling 1 protein.

    Science.gov (United States)

    Li, Bo; Makino, Shin-Ichi; Beebe, Emily T; Urano, Daisuke; Aceti, David J; Misenheimer, Tina M; Peters, Jonathan; Fox, Brian G; Jones, Alan M

    2016-10-01

    Arabidopsis thaliana Regulator of G protein Signalling 1 (AtRGS1) is a protein with a predicted N-terminal 7-transmembrane (7TM) domain and a C-terminal cytosolic RGS1 box domain. The RGS1 box domain exerts GTPase activation (GAP) activity on Gα (AtGPA1), a component of heterotrimeric G protein signaling in plants. AtRGS1 may perceive an exogenous agonist to regulate the steady-state levels of the active form of AtGPA1. It is uncertain if the full-length AtRGS1 protein exerts any atypical effects on Gα, nor has it been established exactly how AtRGS1 contributes to perception of an extracellular signal and transmits this response to a G-protein dependent signaling cascade. Further studies on full-length AtRGS1 have been inhibited due to the extreme low abundance of the endogenous AtRGS1 protein in plants and lack of a suitable heterologous system to express AtRGS1. Here, we describe methods to produce full-length AtRGS1 by cell-free synthesis into unilamellar liposomes and nanodiscs. The cell-free synthesized AtRGS1 exhibits GTPase activating activity on Gα and can be purified to a level suitable for biochemical analyses. PMID:27164033

  13. 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.

  14. Structural Determinants of Arabidopsis thaliana Hyponastic Leaves 1 Function In Vivo

    Science.gov (United States)

    Burdisso, Paula; Milia, Fernando; Schapire, Arnaldo L.; Bologna, Nicolás G.; Palatnik, Javier F.; Rasia, Rodolfo M.

    2014-01-01

    MicroRNAs have turned out to be important regulators of gene expression. These molecules originate from longer transcripts that are processed by ribonuclease III (RNAse III) enzymes. Dicer proteins are essential RNAse III enzymes that are involved in the generation of microRNAs (miRNAs) and other small RNAs. The correct function of Dicer relies on the participation of accessory dsRNA binding proteins, the exact function of which is not well-understood so far. In plants, the double stranded RNA binding protein Hyponastic Leaves 1 (HYL1) helps Dicer Like protein (DCL1) to achieve an efficient and precise excision of the miRNAs from their primary precursors. Here we dissected the regions of HYL1 that are essential for its function in Arabidopsis thaliana plant model. We generated mutant forms of the protein that retain their structure but affect its RNA-binding properties. The mutant versions of HYL1 were studied both in vitro and in vivo, and we were able to identify essential aminoacids/residues for its activity. Remarkably, mutation and even ablation of one of the purportedly main RNA binding determinants does not give rise to any major disturbances in the function of the protein. We studied the function of the mutant forms in vivo, establishing a direct correlation between affinity for the pri-miRNA precursors and protein activity. PMID:25409478

  15. Induction of oxidative stress related responses in Arabidopsis thaliana after uranium exposure

    International Nuclear Information System (INIS)

    Uranium contamination in the environment has resulted from releases linked with nuclear fuel cycle activities and from industries extracting and processing materials containing naturally occurring radionuclides (for example phosphate industry). Uranium toxicity effects are predominantly studied on man and animal species, but little information is available for plants. If phytomanagement of uranium contaminated soils is considered, biological effects on the vegetation have to be investigated. Information on the contamination impact can also be used for risk assessment and derivation of clean-up standards. Plants can experience oxidative stress when they are exposed to environmental stress situations (for example exposure to heavy metals). Reactive oxygen species (ROS) are produced in both stressed and unstressed cells potentially leading to cellular damage. Consequently, plants have developed an antioxidative defence system comprising ROS-scavenging enzymes (e.g. SOD (superoxide dismutase), CAT (catalase) and metabolites (e.g. ascorbate, glutathione). Previous results showed that uranium exposure can cause an imbalance between the oxidative and antioxidative capacities of the plant cells. The present study aimed to analyse biological effects induced in Arabidopsis thaliana after bioaccumulation of uranium and to define possible dose-effect relationships. Subtle effects on the antioxidative defence system (enzymes, metabolites viewed as early responses for individual disturbances (growth, nutrient profile) were analysed

  16. Evaluation of genetic and metabolic role of SKIP11 in Arabidopsis thaliana

    Science.gov (United States)

    Hassan, Muhammad Naeem ul; Ismail, Ismanizan

    2015-09-01

    Most of the regulatory proteins are degraded by 26S proteasome complex, only when they are tagged by Ubiquitin. A complex of four proteins, SKP1-Cullin-Ring box-F box (SCF) catalyses the final step to link the Ubiquitin tag with the target proteins. SCF complex interacts with the target proteins through F-box proteins, which confer the overall substrate specificity to the complex. F-box proteins, one of the largest family of proteins in plants have an N-terminal F-box domain and variable C-terminal domains, like leucine-rich repeat, WD-40 repeat and the kelch-repeat domains. In this study, we analysed the role of SKIP11, a kelch containing F-box protein (KFB) from Arabidopsis thaliana, by using reverse genetics strategy. The results show that SKIP11 is involved in the down-regulation of oxylipin pathway, possibly through the degradation of enzymes or/ and the regulatory factors of the pathway.

  17. Enzymatic and metabolic diagnostic of nitrogen deficiency in Arabidopsis thaliana Wassileskija accession.

    Science.gov (United States)

    Lemaître, Thomas; Gaufichon, Laure; Boutet-Mercey, Stéphanie; Christ, Aurélie; Masclaux-Daubresse, Céline

    2008-07-01

    Adaptation to steady-state low-nutrient availability was investigated by comparing the Wassileskija (WS) accession of Arabidopsis thaliana grown on 2 or 10 mM nitrate. Low nitrogen conditions led to a limited rosette biomass and seed yield. The latter was mainly due to reduced seed number, while seed weight was less affected. However, harvest index was lower in high nitrate compared with limited nitrate conditions. Under nitrogen-limiting conditions, nitrate reductase activity was decreased while glutamine synthetase activity was increased due to a higher accumulation of the cytosolic enzyme. The level of nitrogen remobilization to the seeds was higher under low nitrogen, and the vegetative parts of the plants remaining after seed production stored very low residual nitrogen. Through promoting nitrogen remobilization and recycling pathways, nitrogen limitation modified plant and seed compositions. Rosette leaves contained more sugars and less free amino acids when grown under nitrogen-limiting conditions. Compared with high nitrogen, the levels of proline, asparagine and glutamine were decreased. The seed amino acid composition reflected that of the rosette leaves, thus suggesting that phloem loading for seed filling was poorly selective. The major finding of this report was that together with decreasing biomass and yield, nitrogen limitation triggers large modifications in vegetative products and seed quality. PMID:18508804

  18. 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.

  19. Natural variation in tocochromanols content in Arabidopsis thaliana accessions - the effect of temperature and light intensity.

    Science.gov (United States)

    Gabruk, Michał; Habina, Iwona; Kruk, Jerzy; Dłużewska, Jolanta; Szymańska, Renata

    2016-06-01

    In this study, 25 accessions of Arabidopsis thaliana originating from a variety of climate conditions were grown under controlled circumstances of different light intensity and temperature. The accessions were analyzed for prenyllipids content and composition, as well as expression of the genes involved in tocochromanol biosynthesis (vte1-5). It was found that the applied conditions did not strongly affect total tocochromanols content and there was no apparent correlation of the tocochromanol content with the origin of the accessions. However, the presented results indicate that the temperature, more than the light intensity, affects the expression of the vte1-5 genes and the content of some prenyllipids. An interesting observation was that under low growth temperature, the hydroxy-plastochromanol (PC-OH) to plastochromanol (PC) ratio was considerably increased regardless of the light intensity in most of the accessions. PC-OH is known to be formed as a result of singlet oxygen stress, therefore this observation indicates that the singlet oxygen production is enhanced under low temperature. Unexpectedly, the highest increase in the PC-OH/PC ratio was found for accessions originating from cold climate (Shigu, Krazo-1 and Lov-5), even though such plants could be expected to be more resistant to low temperature stress. PMID:27174597

  20. Post-translational Analysis of Arabidopsis thaliana Proteins in Response to Cyclic Guanosine Monophosphate Treatment

    KAUST Repository

    Parrott, Brian

    2011-12-12

    The introduction of mass spectrometry techniques to the field of biology has made possible the exploration of the proteome as a whole system as opposed to prior techniques, such as anti-body based assays or yeast two-hybrid studies, which were strictly limited to the study of a few proteins at a time. This practice has allowed for a systems biology approach of exploring the proteome, with the possibility of viewing entire pathways over increments of time. In this study, the effect of treating Arabidopsis thaliana suspension culture cells with 3’,5’-cyclic guanosine monophosphate (cGMP), which is a native second messenger, was examined. Samples were collected at four time points and proteins were extracted and enriched for both oxidation and phosphorylation before analysis via mass spectrometry. Preliminary results suggest a tendency towards an increased number of phosphorylated proteins as a result of cGMP treatment. The data also showed a sharp increase in methionine oxidation in response to the treatment, occurring within the first ten minutes. This finding suggests that cGMP may utilize methionine oxidation as a mechanism of signal transduction. As such, this study corroborates a growing body of evidence supporting the inclusion of methionine oxidation in intracellular signaling pathways.

  1. Structural basis for the regulation of N-acetylglutamate kinase by PII in Arabidopsis thaliana.

    Science.gov (United States)

    Mizuno, Yutaka; Moorhead, Greg B G; Ng, Kenneth K-S

    2007-12-01

    PII is a highly conserved regulatory protein found in organisms across the three domains of life. In cyanobacteria and plants, PII relieves the feedback inhibition of the rate-limiting step in arginine biosynthesis catalyzed by N-acetylglutamate kinase (NAGK). To understand the molecular structural basis of enzyme regulation by PII, we have determined a 2.5-A resolution crystal structure of a complex formed between two homotrimers of PII and a single hexamer of NAGK from Arabidopsis thaliana bound to the metabolites N-acetylglutamate, ADP, ATP, and arginine. In PII, the T-loop and Trp(22) at the start of the alpha1-helix, which are both adjacent to the ATP-binding site of PII, contact two beta-strands as well as the ends of two central helices (alphaE and alphaG) in NAGK, the opposing ends of which form major portions of the ATP and N-acetylglutamate substrate-binding sites. The binding of Mg(2+).ATP to PII stabilizes a conformation of the T-loop that favors interactions with both open and closed conformations of NAGK. Interactions between PII and NAGK appear to limit the degree of opening and closing of the active-site cleft in opposition to a domain-separating inhibitory effect exerted by arginine, thus explaining the stimulatory effect of PII on the kinetics of arginine-inhibited NAGK. PMID:17913711

  2. Autophagy induction upon reactive oxygen species in Cd-stressed Arabidopsis thaliana

    Science.gov (United States)

    Zhang, WeiNa; Chen, WenLi

    2010-02-01

    Autophagy is a protein degradation process in which cells recycle cytoplasmic contents when subjected to environmental stress conditions or during certain stages of development. Upon the induction of autophagy, a double membrane autophagosome forms around cytoplasmic components and delivers them to the vacuole for degradation. In plants, autophagy has been shown previously to be induced during abiotic stresses including oxidative stress. Cd, as a toxicity heavy metal, resulted in the production of reactive oxygen species (ROS). In this paper, we demonstrated that ROS contributed to the induction of autophagy in Cd-stressed Arabidopsis thaliana. However, pre-incubation with ascorbic acid (AsA, antioxidant molecule) and catalase (CAT, a H2O2-specific scavenger) decreased the ROS production and the number of autolysosomal-like structures. Together our results indicated that the oxidative condition was essential for autophagy, as treatment with AsA and CAT abolished the formation of autophagosomes, and ROS may function as signal molecules to induce autophagy in abiotic stress.

  3. Sustained mitogen-activated protein kinase activation reprograms defense metabolism and phosphoprotein profile in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Ines eLassowskat

    2014-10-01

    Full Text Available Mitogen-activated protein kinases (MAPKs target a variety of protein substrates to regulate cellular signaling processes in eukaryotes. In plants, the number of identified MAPK substrates that control plant defense responses is still limited. Here, we generated transgenic Arabidopsis thaliana plants with an inducible system to simulate in vivo activation of two stress-activated MAPKs, MPK3 and MPK6. Metabolome analysis revealed that this artificial MPK3/6 activation (without any exposure to pathogens or other stresses is sufficient to drive the production of major defense-related metabolites, including various camalexin, indole glucosinolate and agmatine derivatives. An accompanying (phosphoproteome analysis led to detection of hundreds of potential phosphoproteins downstream of MPK3/6 activation. Besides known MAPK substrates, many candidates on this list possess typical MAPK-targeted phosphosites and in many cases, the corresponding phosphopeptides were detected by mass spectrometry. Notably, several of these putative phosphoproteins have been reported to be associated with the biosynthesis of antimicrobial defense substances (e.g. WRKY transcription factors and proteins encoded by the genes from the PEN pathway required for penetration resistance to filamentous pathogens. Thus, this work provides an inventory of candidate phosphoproteins, including putative direct MAPK substrates, for future analysis of MAPK-mediated defense control. (Proteomics data are available with the identifier PXD001252 via ProteomeXchange, http://proteomecentral.proteomexchange.org.

  4. Structural characterization of the mechanosensitive channel candidate MCA2 from Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Hideki Shigematsu

    Full Text Available Mechanosensing in plants is thought to be governed by sensory complexes containing a Ca²⁺-permeable, mechanosensitive channel. The plasma membrane protein MCA1 and its paralog MCA2 from Arabidopsis thaliana are involved in mechanical stress-induced Ca²⁺ influx and are thus considered as candidates for such channels or their regulators. Both MCA1 and MCA2 were functionally expressed in Sf9 cells using a baculovirus system in order to elucidate their molecular natures. Because of the abundance of protein in these cells, MCA2 was chosen for purification. Purified MCA2 in a detergent-solubilized state formed a tetramer, which was confirmed by chemical cross-linking. Single-particle analysis of cryo-electron microscope images was performed to depict the overall shape of the purified protein. The three-dimensional structure of MCA2 was reconstructed at a resolution of 26 Å from 5,500 particles and appears to comprise a small transmembrane region and large cytoplasmic region.

  5. The evolutionary response of plants to increased UV-B radiation: Field studies with Arabidopsis thaliana

    International Nuclear Information System (INIS)

    The response of a species to any environmental change is determined by both phenotypic and evolutionary adjustments. To date, the majority of research concerning the response of terrestrial plants to increased UV-B radiation has focused on phenotypic adjustments. Recently we have initiated field studies aimed at assessing genetic variation for UV-B sensitivity within a natural population of Arabidopsis thaliana. This population consists of at least eight discrete genotypes that have been confirmed by RAPD analysis. We used an incomplete block design to assess the impact of UV-B (ambient and ambient + 6 kJ) and PAR (low and high) on these genotypes. The high UV-B treatment caused a significant reduction in fruit number and plant height while the high PAR treatment caused a significant increase in these variables. In addition, there was a marginally significant (p=0.1) UV-B x PAR x maternal line interaction for fruit number, indicating that genetic variation for UV-B sensitivity within this population depends on the PAR environment. The combination of high UV-B and high PAR caused a change in fruit number (relative to the ambient UV-B/high PAR treatment) ranging from an increase of 24% to a decrease of 47%. This range was much smaller in the low PAR treatment. These results indicate the potential for increased UV-B radiation to act as an agent of natural selection within this population

  6. Structure, inhibition and regulation of two-pore channel TPC1 from Arabidopsis thaliana.

    Science.gov (United States)

    Kintzer, Alexander F; Stroud, Robert M

    2016-03-10

    Two-pore channels (TPCs) comprise a subfamily (TPC1-3) of eukaryotic voltage- and ligand-gated cation channels with two non-equivalent tandem pore-forming subunits that dimerize to form quasi-tetramers. Found in vacuolar or endolysosomal membranes, they regulate the conductance of sodium and calcium ions, intravesicular pH, trafficking and excitability. TPCs are activated by a decrease in transmembrane potential and an increase in cytosolic calcium concentrations, are inhibited by low luminal pH and calcium, and are regulated by phosphorylation. Here we report the crystal structure of TPC1 from Arabidopsis thaliana at 2.87 Å resolution as a basis for understanding ion permeation, channel activation, the location of voltage-sensing domains and regulatory ion-binding sites. We determined sites of phosphorylation in the amino-terminal and carboxy-terminal domains that are positioned to allosterically modulate cytoplasmic Ca(2+) activation. One of the two voltage-sensing domains (VSD2) encodes voltage sensitivity and inhibition by luminal Ca(2+) and adopts a conformation distinct from the activated state observed in structures of other voltage-gated ion channels. The structure shows that potent pharmacophore trans-Ned-19 (ref. 17) acts allosterically by clamping the pore domains to VSD2. In animals, Ned-19 prevents infection by Ebola virus and other filoviruses, presumably by altering their fusion with the endolysosome and delivery of their contents into the cytoplasm. PMID:26961658

  7. 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.

  8. Early life stages contribute strongly to local adaptation in Arabidopsis thaliana.

    Science.gov (United States)

    Postma, Froukje M; Ågren, Jon

    2016-07-01

    The magnitude and genetic basis of local adaptation is of fundamental interest in evolutionary biology. However, field experiments usually do not consider early life stages, and therefore may underestimate local adaptation and miss genetically based tradeoffs. We examined the contribution of differences in seedling establishment to adaptive differentiation and the genetic architecture of local adaptation using recombinant inbred lines (RIL) derived from a cross between two locally adapted populations (Italy and Sweden) of the annual plant Arabidopsis thaliana We planted freshly matured, dormant seeds (>180 000) representing >200 RILs at the native field sites of the parental genotypes, estimated the strength of selection during different life stages, mapped quantitative trait loci (QTL) for fitness and its components, and quantified selection on seed dormancy. We found that selection during the seedling establishment phase contributed strongly to the fitness advantage of the local genotype at both sites. With one exception, local alleles of the eight distinct establishment QTL were favored. The major QTL for establishment and total fitness showed evidence of a fitness tradeoff and was located in the same region as the major seed dormancy QTL and the dormancy gene DELAY OF GERMINATION 1 (DOG1). RIL seed dormancy could explain variation in seedling establishment and fitness across the life cycle. Our results demonstrate that genetically based differences in traits affecting performance during early life stages can contribute strongly to adaptive differentiation and genetic tradeoffs, and should be considered for a full understanding of the ecology and genetics of local adaptation. PMID:27330113

  9. Characterization of Two H2AX Homologues in Arabidopsis thaliana and their Response to Ionizing Radiation

    International Nuclear Information System (INIS)

    Phosphorylation of histone variant H2AX at the site of DNA double-strand breaks (DSB) is one of the earliest responses detected in cells exposed to Ionizing Radiation (IR). Phosphorylated H2AX (γ-H2AX) is important for recruiting and retaining repair proteins at the site of DSBs and contributes to the maintenance of cell-cycle arrest until repair is completed. In this study, insertional mutants of two Arabidopsis thaliana H2AX homologues were identified and characterized to determine if both genes are functionally active and whether their roles are redundant or divergent. We report an approximate ten-fold reduction in γ-H2AX in our double mutant line and demonstrate that the homologues function redundantly in the formation of IR induced γ-H2AX foci. A tendency towards increased inhibition of root growth was observed in irradiated double mutant plants relative to both wild-type and single mutant lines. No evidence indicating a functional divergence between the two homologues was detected. (author)

  10. Influence of atmospheric oxygen on leaf structure and starch deposition in Arabidopsis thaliana

    Science.gov (United States)

    Ramonell, K. M.; Kuang, A.; Porterfield, D. M.; Crispi, M. L.; Xiao, Y.; McClure, G.; Musgrave, M. E.

    2001-01-01

    Plant culture in oxygen concentrations below ambient is known to stimulate vegetative growth, but apart from reports on increased leaf number and weight, little is known about development at subambient oxygen concentrations. Arabidopsis thaliana (L.) Heynh. (cv. Columbia) plants were grown full term in pre-mixed atmospheres with oxygen partial pressures of 2.5, 5.1, 10.1, 16.2, and 21.3 kPa O2, 0.035 kPa CO2 and the balance nitrogen under continuous light. Fully expanded leaves were harvested and processed for light and transmission electron microscopy or for starch quantification. Growth in subambient oxygen concentrations caused changes in leaf anatomy (increased thickness, stomatal density and starch content) that have also been described for plants grown under carbon dioxide enrichment. However, at the lowest oxygen treatment (2.5 kPa), developmental changes occurred that could not be explained by changes in carbon budget caused by suppressed photorespiration, resulting in very thick leaves and a dwarf morphology. This study establishes the leaf parameters that change during growth under low O2, and identifies the lower concentration at which O2 limitation on transport and biosynthetic pathways detrimentally affects leaf development. Grant numbers: NAG5-3756, NAG2-1020, NAG2-1375.

  11. Comprehensive Analysis of the Membrane Phosphoproteome Regulated by Oligogalacturonides in Arabidopsis thaliana

    Science.gov (United States)

    Mattei, Benedetta; Spinelli, Francesco; Pontiggia, Daniela; De Lorenzo, Giulia

    2016-01-01

    Early changes in the Arabidopsis thaliana membrane phosphoproteome in response to oligogalacturonides (OGs), a class of plant damage-associated molecular patterns (DAMPs), were analyzed by two complementary proteomic approaches. Differentially phosphorylated sites were determined through phosphopeptide enrichment followed by LC-MS/MS using label-free quantification; differentially phosphorylated proteins were identified by 2D-DIGE combined with phospho-specific fluorescent staining (phospho-DIGE). This large-scale phosphoproteome analysis of early OG-signaling enabled us to determine 100 regulated phosphosites using LC-MS/MS and 46 differential spots corresponding to 34 pdhosphoproteins using phospho-DIGE. Functional classification showed that the OG-responsive phosphoproteins include kinases, phosphatases and receptor-like kinases, heat shock proteins (HSPs), reactive oxygen species (ROS) scavenging enzymes, proteins related to cellular trafficking, transport, defense and signaling as well as novel candidates for a role in immunity, for which elicitor-induced phosphorylation changes have not been shown before. A comparison with previously identified elicitor-regulated phosphosites shows only a very limited overlap, uncovering the immune-related regulation of 70 phosphorylation sites and revealing novel potential players in the regulation of elicitor-dependent immunity. PMID:27532006

  12. Hormonal response and root architecture in Arabidopsis thaliana subjected to heavy metals

    Directory of Open Access Journals (Sweden)

    Antonella Vitti

    2014-05-01

    Full Text Available In this work, specific concentrations of cadmium, copper and zinc in double combination, were supplied for 12 days to growing seedlings of the model species Arabidopsis thaliana. Metal accumulation was measured in roots and shoots. Microscopic analyses revealed that root morphology was affected by metals, and that the root and shoot levels of indole-3-acetic acid, trans-zeatin riboside and dihydrozeatin riboside varied accordingly. Minor modifications in gibberellic acid levels occurred in the Zinc treatments, whereas abscisic acid level did not change after the exposition to metals. Reverse transcription polymerase chain reaction analysis of some genes involved in auxin and cytokinin synthesis (AtAAO, AtNIT and AtIPT revealed that their expression were not affected by metal treatments. The root morphological alterations that resulted in an increased surface area, due to the formation of root hairs and lateral roots, could be signs of the response to metal stress in terms of a functionally-addressed reorientation of root growth. The root system plasticity observed could be important for better understanding the manner in which the root architecture is shaped by environmental and hormonal stimuli.

  13. On the Origin of De Novo Genes in Arabidopsis thaliana Populations.

    Science.gov (United States)

    Li, Zi-Wen; Chen, Xi; Wu, Qiong; Hagmann, Jörg; Han, Ting-Shen; Zou, Yu-Pan; Ge, Song; Guo, Ya-Long

    2016-01-01

    De novo genes, which originate from ancestral nongenic sequences, are one of the most important sources of protein-coding genes. This origination process is crucial for the adaptation of organisms. However, how de novo genes arise and become fixed in a population or species remains largely unknown. Here, we identified 782 de novo genes from the model plant Arabidopsis thaliana and divided them into three types based on the availability of translational evidence, transcriptional evidence, and neither transcriptional nor translational evidence for their origin. Importantly, by integrating multiple types of omics data, including data from genomes, epigenomes, transcriptomes, and translatomes, we found that epigenetic modifications (DNA methylation and histone modification) play an important role in the origination process of de novo genes. Intriguingly, using the transcriptomes and methylomes from the same population of 84 accessions, we found that de novo genes that are transcribed in approximately half of the total accessions within the population are highly methylated, with lower levels of transcription than those transcribed at other frequencies within the population. We hypothesized that, during the origin of de novo gene alleles, those neutralized to low expression states via DNA methylation have relatively high probabilities of spreading and becoming fixed in a population. Our results highlight the process underlying the origin of de novo genes at the population level, as well as the importance of DNA methylation in this process. PMID:27401176

  14. Unraveling the WRKY transcription factors network in Arabidopsis Thaliana by integrative approach

    Directory of Open Access Journals (Sweden)

    Mouna Choura

    2015-06-01

    Full Text Available The WRKY transcription factors superfamily are involved in diverse biological processes in plants including response to biotic and abiotic stresses and plant immunity. Protein-protein interaction network is a useful approach for understanding these complex processes. The availability of Arabidopsis Thaliana interactome offers a good opportunity to do get a global view of protein network. In this work, we have constructed the WRKY transcription factor network by combining different sources of evidence and we characterized its topological features using computational tools. We found that WRKY network is a hub-based network involving multifunctional proteins denoted as hubs such as WRKY 70, WRKY40, WRKY 53, WRKY 60, WRKY 33 and WRKY 51. Functional annotation showed seven functional modules particularly involved in biotic stress and defense responses. Furthermore, the gene ontology and pathway enrichment analysis revealed that WRKY proteins are mainly involved in plant-pathogen interaction pathways and their functions are directly related to the stress response and immune system process.

  15. Structural analysis and physical mapping of a pericentromeric region of chromosome 5 of Arabidopsis thaliana.

    Science.gov (United States)

    Tutois, S; Cloix, C; Cuvillier, C; Espagnol, M C; Lafleuriel, J; Picard, G; Tourmente, S

    1999-01-01

    The Arabidopsis thaliana CIC YAC 2D2, 510 kb long and containing a small block of 180 bp satellite units was subcloned after EcoR1 digestion in the pBluescript plasmid. One of these clones was mapped genetically in the pericentromeric region of chromosome 5. The analysis of 40 subclones of this YAC showed that they all contain repeated sequences with a high proportion of transposable elements. Three new retrotransposons, two Ty-3 Gypsy-like and one Ty-1 Copia, were identified in addition to two new tandem-repeat families. A physical map of the chromosome 5 pericentromeric region was established using CIC YAC clones, spanning around 1000 kb. This contig extends from the CIC YAC 9F5 and 7A2 positioned on the left arm of chromosome 5 to a 5S rDNA genes block localized by in-situ hybridization in the pericentromeric region. Hybridization of the subclones on the CIC YAC library showed that some of them are restricted to the pericentromeric region of chromosome 5 and represent specific markers of this region. PMID:10328626

  16. The dominance of the herbicide resistance cost in several Arabidopsis thaliana mutant lines.

    Science.gov (United States)

    Roux, Fabrice; Gasquez, Jacques; Reboud, Xavier

    2004-01-01

    Resistance evolution depends upon the balance between advantage and disadvantage (cost) conferred in treated and untreated areas. By analyzing morphological characters and simple fitness components, the cost associated with each of eight herbicide resistance alleles (acetolactate synthase, cellulose synthase, and auxin-induced target genes) was studied in the model plant Arabidopsis thaliana. The use of allele-specific PCR to discriminate between heterozygous and homozygous plants was used to provide insights into the dominance of the resistance cost, a parameter rarely described. Morphological characters appear more sensitive than fitness (seed production) because 6 vs. 4 differences between resistant and sensitive homozygous plants were detected, respectively. Dominance levels for the fitness cost ranged from recessivity (csr1-1, ixr1-2, and axr1-3) to dominance (axr2-1) to underdominance (aux1-7). Furthermore, the dominance level of the herbicide resistance trait did not predict the dominance level of the cost of resistance. The relationship of our results to theoretical predictions of dominance and the consequences of fitness cost and its dominance in resistance management are discussed. PMID:15020435

  17. Building of an experimental cline with Arabidopsis thaliana to estimate herbicide fitness cost.

    Science.gov (United States)

    Roux, Fabrice; Giancola, Sandra; Durand, Stéphanie; Reboud, Xavier

    2006-06-01

    Various management strategies aim at maintaining pesticide resistance frequency under a threshold value by taking advantage of the benefit of the fitness penalty (the cost) expressed by the resistance allele outside the treated area or during the pesticide selection "off years." One method to estimate a fitness cost is to analyze the resistance allele frequency along transects across treated and untreated areas. On the basis of the shape of the cline, this method gives the relative contributions of both gene flow and the fitness difference between genotypes in the treated and untreated areas. Taking advantage of the properties of such migration-selection balance, an artificial cline was built up to optimize the conditions where the fitness cost of two herbicide-resistant mutants (acetolactate synthase and auxin-induced target genes) in the model species Arabidopsis thaliana could be more accurately measured. The analysis of the microevolutionary dynamics in these experimental populations indicated mean fitness costs of approximately 15 and 92% for the csr1-1 and axr2-1 resistances, respectively. In addition, negative frequency dependence for the fitness cost was also detected for the axr2-1 resistance. The advantages and disadvantages of the cline approach are discussed in regard to other methods of cost estimation. This comparison highlights the powerful ability of an experimental cline to measure low fitness costs and detect sensibility to frequency-dependent variations. PMID:16582450

  18. Multigenerational versus single generation studies to estimate herbicide resistance fitness cost in Arabidopsis thaliana.

    Science.gov (United States)

    Roux, Fabrice; Camilleri, Christine; Bérard, Aurélie; Reboud, Xavier

    2005-10-01

    The evolution of resistance in response to pesticide selection is expected to be delayed if fitness costs are associated with resistance genes. The estimate of fitness costs usually involves comparing major growth traits of resistant versus susceptible individuals in the absence of pesticide. Ideally, a measure of changes in resistance allele frequency over several generations would allow the best estimate of the overall fitness cost of a resistance gene. In greenhouse conditions, we monitored the dynamics of the evolution of the frequencies of six herbicide-resistant mutations (acetolactate synthase, cellulose synthase, and auxin-induced target genes) in the model species Arabidopsis thaliana in a multigenerational study covering five to seven nonoverlapping generations. The microevolutionary dynamics in experimental populations indicated a mean fitness cost of 38%, 73%, and 94% for the ixr1-2, axr1-3, and axr2-1 resistances, respectively; no fitness cost for the csr1-1, and ixr2-1 resistances; and a transient advantage for the aux1-7 resistance. The result for the csr1-1 resistance contrasts with a cost of 37% based on total seed number in a previous study, demonstrating that single generation studies could have limitation for detecting cost. A positive frequency dependence for the fitness cost was also detected for the ixr1-2 resistance. The results are discussed in relation to the maintenance of polymorphism at resistance loci. PMID:16405169

  19. Newly Described Components and Regulatory Mechanisms of Circadian Clock Function in Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    Manuel Adrián Troncoso-Ponce; Paloma Mas

    2012-01-01

    The circadian clock temporally coordinates plant growth and metabolism in close synchronization with the diurnal and seasonal environmental changes.Research over the last decade has identified a number of clock components and a variety of regulatory mechanisms responsible for the rhythmic oscillations in metabolic and physiological activities.At the core of the clock,transcriptional/translational feedback loops modulate the expression of a significant proportion of the genome.In this article,we briefly describe some of the very recent advances that have improved our understanding of clock organization and function in Arabidopsis thaliana.The new studies illustrate the role of clock protein complex formation on circadian gating of plant growth and identify alternative splicing as a new regulatory mechanism for clock function.Examination of key clock properties such as temperature compensation has also opened new avenues for functional research within the plant clockwork.The emerging connections between the circadian clock and metabolism,hormone signaling and response to biotic and abiotic stress also add new layers of complexity to the clock network and underscore the significance of the circadian clock regulating the daily life of plants.

  20. Jasmonate is involved in the induction of tyrosine aminotransferase and tocopherol biosynthesis in Arabidopsis thaliana.

    Science.gov (United States)

    Sandorf, Iris; Holländer-Czytko, Heike

    2002-11-01

    Coronatine-inducible tyrosine aminotransferase (TAT), which catalyses the transamination from tyrosine to p-hydroxyphenylpyruvate, is the first enzyme of a pathway leading via homogentisic acid to plastoquinone and tocopherols, the latter of which are known to be radical scavengers in plants. TAT can be also induced by the octadecanoids methyl jasmonate (MeJA) and methyl-12-oxophytodienoic acid (MeOPDA), as well as by wounding, high light, UV light and the herbicide oxyfluorfen. In order to elucidate the role of octadecanoids in the process of TAT induction in Arabidopsis thaliana (L.) Heynh., the jasmonate-deficient mutant delayed dehiscence (dde1) was used, in which the gene for 12-oxophytodienoic acid reductase 3 is disrupted. The amount of immunodetectable TAT was low. The enzyme was still fully induced by coronatine as well as by MeJA although induction by the latter was to a lesser extent and later than in the wild type. Treatment with MeOPDA, wounding and UV light, however, had hardly any effects. Tocopherol levels that showed considerable increases in the wild type after some treatments were much less affected in the mutant. However, starting levels of tocopherol were higher in non-induced dde1 than in the wild type. We conclude that jasmonate plays an important role in the signal transduction pathway regulating TAT activity and the biosynthesis of its product tocopherol. PMID:12430028

  1. Statistical modeling of nitrogen-dependent modulation of root system architecture in Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    Takao Araya; Takuya Kubo; Nicolaus von Wiren; Hideki Takahashi

    2016-01-01

    Plant root development is strongly affected by nutrient availability. Despite the importance of structure and function of roots in nutrient acquisition, statistical modeling approaches to evaluate dynamic and temporal modulations of root system architecture in response to nutrient availability have remained as widely open and exploratory areas in root biology. In this study, we developed a statistical modeling approach to investigate modulations of root system archi-tecture in response to nitrogen availability. Mathematical models were designed for quantitative assessment of root growth and root branching phenotypes and their dynamic relationships based on hierarchical configuration of primary and lateral roots formulating the fishbone-shaped root system architecture in Arabidopsis thaliana. Time-series datasets reporting dynamic changes in root developmental traits on different nitrate or ammonium concentrations were gener-ated for statistical analyses. Regression analyses unraveled key parameters associated with:(i) inhibition of primary root growth under nitrogen limitation or on ammonium;(i ) rapid progression of lateral root emergence in response to ammonium; and (i i) inhibition of lateral root elongation in the presence of excess nitrate or ammonium. This study provides a statistical framework for interpreting dynamic modulation of root system architecture, supported by meta-analysis of datasets displaying morphological responses of roots to diverse nitrogen supplies.

  2. Polyol specificity of recombinant Arabidopsis thaliana sorbitol dehydrogenase studied by enzyme kinetics and in silico modeling

    Directory of Open Access Journals (Sweden)

    María Francisca eAguayo

    2015-02-01

    Full Text Available Polyols are enzymatically-produced plant compounds which can act as compatible solutes during periods of abiotic stress. NAD+-dependent SORBITOL DEHYDROGENASE (SDH, E.C. 1.1.1.14 from Arabidopsis thaliana L. (AtSDH is capable of oxidizing several polyols including sorbitol, ribitol and xylitol. In the present study, enzymatic assays using recombinant AtSDH demonstrated a higher specificity constant for xylitol compared to sorbitol and ribitol, all of which are C2 (S and C4 (R polyols. Enzyme activity was reduced by preincubation with ethylenediaminetetraacetic acid (EDTA, indicating a requirement for zinc ions. In humans, it has been proposed that sorbitol becomes part of a pentahedric coordination sphere of the catalytic zinc during the reaction mechanism. In order to determine the validity of this pentahedric coordination model in a plant SDH, homology modeling and Molecular Dynamics simulations of AtSDH ternary complexes with the three polyols were performed using crystal structures of human and Bemisia argentifolii (Genn. (Hemiptera: Aleyrodidae SDHs as scaffolds. The results indicate that the differences in interaction with structural water molecules correlate very well with the observed enzymatic parameters, validate the proposed pentahedric coordination of the catalytic zinc ion in a plant SDH, and provide an explanation for why AtSDH shows a preference for polyols with a chirality of C2 (S and C4 (R.

  3. Redirection of auxin flow in Arabidopsis thaliana roots after infection by root-knot nematodes.

    Science.gov (United States)

    Kyndt, Tina; Goverse, Aska; Haegeman, Annelies; Warmerdam, Sonja; Wanjau, Cecilia; Jahani, Mona; Engler, Gilbert; de Almeida Engler, Janice; Gheysen, Godelieve

    2016-08-01

    Plant-parasitic root-knot nematodes induce the formation of giant cells within the plant root, and it has been recognized that auxin accumulates in these feeding sites. Here, we studied the role of the auxin transport system governed by AUX1/LAX3 influx proteins and different PIN efflux proteins during feeding site development in Arabidopsis thaliana roots. Data generated via promoter-reporter line and protein localization analyses evoke a model in which auxin is being imported at the basipetal side of the feeding site by the concerted action of the influx proteins AUX1 and LAX3, and the efflux protein PIN3. Mutants in auxin influx proteins AUX1 and LAX3 bear significantly fewer and smaller galls, revealing that auxin import into the feeding sites is needed for their development and expansion. The feeding site development in auxin export (PIN) mutants was only slightly hampered. Expression of some PINs appears to be suppressed in galls, probably to prevent auxin drainage. Nevertheless, a functional PIN4 gene seems to be a prerequisite for proper nematode development and gall expansion, most likely by removing excessive auxin to stabilize the hormone level in the feeding site. Our data also indicate a role of local auxin peaks in nematode attraction towards the root. PMID:27312670

  4. 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.

  5. Isolation and characterization of hormone-autonomous tumours of Arabidopsis thaliana

    International Nuclear Information System (INIS)

    In order to study the molecular genetics of factors controlling plant cell growth, we have isolated and begun to characterize a set of tumours on the small crucifer Arabidopsis thaliana. Seeds or seedlings were exposed to 60Co gamma radiation and, 30–60 d after germination, tumours developed either on the hypocotyl or in the region of the apical meristem of about 1% of the plants. When excised and placed in culture, some of these tumours were found to be capable of hormone-independent growth. The tumours exhibit a number of different phenotypes, varying in colour, texture, and degree of differentiation. Some tumours appear to be completely undifferentiated, one consistently produces roots, and others show the sporadic appearance of shoots or leaflets. Doubling times of the tumours on hormone-free medium range from approximately 2 d to 9 d. We propose that these tumours arose due to heritable changes in the genome which result in altered expression of important growth-regulatory genes. Preliminary investigations of gene expression in the tumours have led to the identification of an mRNA that is abundant in all of the tumours, differentially expressed in plant organs and hormone-dependent callus grown on different auxins, and which encodes a putative glycine-rich protein. (author)

  6. Characterization of a novel Kazal-type serine proteinase inhibitor of Arabidopsis thaliana.

    Science.gov (United States)

    Pariani, Sebastián; Contreras, Marisol; Rossi, Franco R; Sander, Valeria; Corigliano, Mariana G; Simón, Francisco; Busi, María V; Gomez-Casati, Diego F; Pieckenstain, Fernando L; Duschak, Vilma G; Clemente, Marina

    2016-04-01

    Many different types of serine proteinase inhibitors have been involved in several kinds of plant physiological processes, including defense mechanisms against phytopathogens. Kazal-type serine proteinase inhibitors, which are included in the serine proteinase inhibitor family, are present in several organisms. These proteins play a regulatory role in processes that involve serine proteinases like trypsin, chymotrypsin, thrombin, elastase and/or subtilisin. In the present work, we characterized two putative Kazal-type serine proteinase inhibitors from Arabidopsis thaliana, which have a single putative Kazal-type domain. The expression of these inhibitors is transiently induced in response to leaf infection by Botrytis cinerea, suggesting that they play some role in defense against pathogens. We also evaluated the inhibitory specificity of one of the Kazal-type serine proteinase inhibitors, which resulted to be induced during the local response to B. cinerea infection. The recombinant Kazal-type serine proteinase inhibitor displayed high specificity for elastase and subtilisin, but low specificity for trypsin, suggesting differences in its selectivity. In addition, this inhibitor exhibited a strong antifungal activity inhibiting the germination rate of B. cinerea conidia in vitro. Due to the important role of proteinase inhibitors in plant protection against pathogens and pests, the information about Kazal-type proteinase inhibitors described in the present work could contribute to improving current methods for plant protection against pathogens. PMID:26853817

  7. The relationship between leaf area growth and biomass accumulation in Arabidopsis thaliana.

    Science.gov (United States)

    Weraduwage, Sarathi M; Chen, Jin; Anozie, Fransisca C; Morales, Alejandro; Weise, Sean E; Sharkey, Thomas D

    2015-01-01

    Leaf area growth determines the light interception capacity of a crop and is often used as a surrogate for plant growth in high-throughput phenotyping systems. The relationship between leaf area growth and growth in terms of mass will depend on how carbon is partitioned among new leaf area, leaf mass, root mass, reproduction, and respiration. A model of leaf area growth in terms of photosynthetic rate and carbon partitioning to different plant organs was developed and tested with Arabidopsis thaliana L. Heynh. ecotype Columbia (Col-0) and a mutant line, gigantea-2 (gi-2), which develops very large rosettes. Data obtained from growth analysis and gas exchange measurements was used to train a genetic programming algorithm to parameterize and test the above model. The relationship between leaf area and plant biomass was found to be non-linear and variable depending on carbon partitioning. The model output was sensitive to the rate of photosynthesis but more sensitive to the amount of carbon partitioned to growing thicker leaves. The large rosette size of gi-2 relative to that of Col-0 resulted from relatively small differences in partitioning to new leaf area vs. leaf thickness. PMID:25914696

  8. 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.

  9. Changes in the population of seed bacteria of transgenerationally Cd-exposed Arabidopsis thaliana.

    Science.gov (United States)

    Truyens, S; Weyens, N; Cuypers, A; Vangronsveld, J

    2013-11-01

    Plant-associated bacteria can have beneficial effects on the growth and health of their host. Nevertheless, the role of endophytic bacteria present in seeds has not been investigated in depth. In this study, the cultivable endophytic population of seeds from Arabidopsis thaliana exposed to 2 μm cadmium for several generations (Cd seeds) was compared with a population isolated from seeds of plants that were never exposed to Cd (control seeds). We observed obvious differences between the two types of seed concerning genera present and phenotypic characteristics of the different isolates. Sinorhizobium sp. and Micrococcus sp. were only found in control seeds, while Pseudomonas sp., Bosea sp. and Paenibacillus sp. were only found in Cd seeds. Sphingomonas sp., Rhizobium sp., Acidovorax sp., Variovorax sp., Methylobacterium sp., Bacillus sp. and Staphylococcus sp. occurred in varying numbers in both types of seed. Metal tolerance and 1-aminocyclopropane-1-carboxylate deaminase activity were predominantly found in strains isolated from Cd seeds, while the production of siderophores, indole-3-acetic acid and organic acids was more prevalent in endophytes isolated from control seeds. These data support the hypothesis that certain endophytes are selected for transfer to the next generation and that their presence might be important for subsequent germination and early seedling development. PMID:23252960

  10. Ky-2, a Histone Deacetylase Inhibitor, Enhances High-Salinity Stress Tolerance in Arabidopsis thaliana.

    Science.gov (United States)

    Sako, Kaori; Kim, Jong-Myong; Matsui, Akihiro; Nakamura, Kotaro; Tanaka, Maho; Kobayashi, Makoto; Saito, Kazuki; Nishino, Norikazu; Kusano, Miyako; Taji, Teruaki; Yoshida, Minoru; Seki, Motoaki

    2016-04-01

    Adaptation to environmental stress requires genome-wide changes in gene expression. Histone modifications are involved in gene regulation, but the role of histone modifications under environmental stress is not well understood. To reveal the relationship between histone modification and environmental stress, we assessed the effects of inhibitors of histone modification enzymes during salinity stress. Treatment with Ky-2, a histone deacetylase inhibitor, enhanced high-salinity stress tolerance in Arabidopsis. We confirmed that Ky-2 possessed inhibition activity towards histone deacetylases by immunoblot analysis. To investigate how Ky-2 improved salt stress tolerance, we performed transcriptome and metabolome analysis. These data showed that the expression of salt-responsive genes and salt stress-related metabolites were increased by Ky-2 treatment under salinity stress. A mutant deficient inAtSOS1(Arabidopis thaliana SALT OVERLY SENSITIVE 1), which encodes an Na(+)/H(+)antiporter and was among the up-regulated genes, lost the salinity stress tolerance conferred by Ky-2. We confirmed that acetylation of histone H4 atAtSOS1was increased by Ky-2 treatment. Moreover, Ky-2 treatment decreased the intracellular Na(+)accumulation under salinity stress, suggesting that enhancement of SOS1-dependent Na(+)efflux contributes to increased high-salinity stress tolerance caused by Ky-2 treatment. PMID:26657894

  11. Identification of Adenyl Cyclase Activity in a Disease Resistance Protein in Arabidopsis thaliana

    KAUST Repository

    Hussein, Rana

    2012-11-01

    Cyclic nucleotide, cAMP, is an important signaling molecule in animals and plants. However, in plants the enzymes that synthesize this second messenger, adenyl cyclases (ACs), remain elusive. Given the physiological importance of cAMP in signaling, particularly in response to biotic and abiotic stresses, it is thus important to identify and characterize ACs in higher plants. Using computational approaches, a disease resistance protein from Arabidopsis thaliana, At3g04220 was found to have an AC catalytic center motif. In an attempt to prove that this candidate has adenyl cyclases activity in vitro, the coding sequence of the putative AC catalytic domain of this protein was cloned and expressed in E. coli and the recombinant protein was purified. The nucleotide cyclase activity of the recombinant protein was examined using cyclic nucleotide enzyme immunoassays. In parallel, the expression of At3g04220 was measured in leaves under three different stress conditions in order to determine under which conditions the disease resistance protein could function. Results show that the purified recombinant protein has Mn2+ dependent AC activity in vitro, and the expression analysis supports a role for At3g04220 and cAMP in plant defense.

  12. Gibberellic acid and cGMP-dependent transcriptional regulation in arabidopsis thaliana

    KAUST Repository

    Bastian, René

    2010-03-01

    An ever increasing amount of transcriptomic data and analysis tools provide novel insight into complex responses of biological systems. Given these resources we have undertaken to review aspects of transcriptional regulation in response to the plant hormone gibberellic acid (GA) and its second messenger guanosine 3\\',5\\'-cyclic monophosphate (cGMP) in Arabidopsis thaliana, both wild type and selected mutants. Evidence suggests enrichment of GA-responsive (GARE) elements in promoters of genes that are transcriptionally upregulated in response to cGMP but downregulated in a GA insensitive mutant (ga1-3). In contrast, in the genes upregulated in the mutant, no enrichment in the GARE is observed suggesting that GARE motifs are diagnostic for GA-induced and cGMP-dependent transcriptional upregulation. Further, we review how expression studies of GA-dependent transcription factors and transcriptional networks based on common promoter signatures derived from ab initio analyses can contribute to our understanding of plant responses at the systems level. © 2010 Landes Bioscience.

  13. Proteomic signatures implicate cAMP in light and temperature responses in Arabidopsis thaliana

    KAUST Repository

    Thomas, Ludivine

    2013-05-01

    The second messenger 3\\'-5\\'-cyclic adenosine monophosphate (cAMP) and adenylyl cyclases (ACs), enzymes that catalyse the formation of cAMP from ATP, are increasingly recognized as important signaling molecules in a number of physiological responses in higher plants. Here we used proteomics to identify cAMP-dependent protein signatures in Arabidopsis thaliana and identify a number of differentially expressed proteins with a role in light- and temperature-dependent responses, notably photosystem II subunit P-1, plasma membrane associated cation-binding protein and chaperonin 60 β. Based on these proteomics results we conclude that, much like in cyanobacteria, algae and fungi, cAMP may have a role in light signaling and the regulation of photosynthesis as well as responses to temperature and we speculate that ACs could act as light and/or temperature sensors in higher plants. Biological significance: This current study is significant since it presents the first proteomic response to cAMP, a novel and key second messenger in plants. It will be relevant to researchers in plant physiology and in particular those with an interest in second messengers and their role in biotic and abiotic stress responses. © 2013 Elsevier B.V.

  14. 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.

  15. Photosynthetic Properties of Photosystem Ⅱ in Arabidopsis thaliana Ipa1 Mutant

    Institute of Scientific and Technical Information of China (English)

    Lian-Wei Peng; Jin-Kui Guo; Jin-Fang Ma; Wei Chi; Li-Xin Zhang

    2006-01-01

    In a previous study, we characterized a high chlorophyll fluorescence Ipa1 mutant of Arabidopsis thaliana,in which approximately 20% photosystem (PS) Ⅱ protein is accumulated. In the present study, analysis of fluorescence decay kinetics and thermoluminescence profiles demonstrated that the electron transfer reaction on either the donor or acceptor side of PSll remained largely unaffected in the Ipa1 mutant. In the mutant, maximal photochemical efficiency (Fv/Fm, where Fm is the maximum fluorescence yield and Fv is variable fluorescence) decreased with increasing light intensity and remained almost unchanged in wildtype plants under different light conditions. The Fv/Fm values also increased when mutant plants were transferred from standard growth light to low light conditions. Analysis of PSⅡ protein accumulation further confirmed that the amount of PSll reaction center protein is correlated with changes in Fv/Fm in Ipa1 plants.Thus, the assembled PSll in the mutant was functional and also showed increased photosensitivity compared with wild-type plants.

  16. Changes in leaf proteome profile of Arabidopsis thaliana in response to salicylic acid

    Indian Academy of Sciences (India)

    Riddhi Datta; Ragini Sinha; Sharmila Chattopadhyay

    2013-06-01

    Salicylic acid (SA) has been implicated in determining the outcome of interactions between many plants and their pathogens. Global changes in response to this phytohormone have been observed at the transcript level, but little is known of how it induces changes in protein abundance. To this end we have investigated the effect of 1 mM SA on soluble proteins of Arabidopsis thaliana leaves by proteomic analysis. An initial study at transcript level has been performed on temporal landscape, which revealed that induction of most of the SA-responsive genes occurs within 3 to 6 h post treatment (HPT) and the expression peaked within 24 HPT. Two-dimensional gel electrophoresis (2-DE) coupled with MALDI-TOF MS/MS analysis has been used to identify differentially expressed proteins and 63 spots have been identified successfully. This comparative proteomic profiling of SA treated leaves versus control leaves demonstrated the changes of many defence related proteins like pathogenesis related protein 10a (PR10a), disease-resistance-like protein, putative late blight-resistance protein, WRKY4, MYB4, etc. along with gross increase in the rate of energy production, while other general metabolism rate is slightly toned down, presumably signifying a transition from ‘normal mode’ to ‘defence mode’.

  17. Transgenic AEQUORIN reveals organ-specific cytosolic Ca2+ responses to anoxia and Arabidopsis thaliana seedlings

    Science.gov (United States)

    Sedbrook, J. C.; Kronebusch, P. J.; Borisy, G. G.; Trewavas, A. J.; Masson, P. H.

    1996-01-01

    Using the transgenic AEQUORIN system, we showed that the cotyledons and leaves of Arabidopsis thaliana seedlings developed a biphasic luminescence response to anoxia, indicating changes in cytosolic Ca2+ levels. A fast and transient luminescence peak occurred within minutes of anoxia, followed by a second, prolonged luminescence response that lasted 1.5 to 4 h. The Ca2+ channel blockers Gd3+, La3+, and ruthenium red (RR) partially inhibited the first response and promoted a larger and earlier second response, suggesting different origins for these responses. Both Gd3+ and RR also partially inhibited anaerobic induction of alcohol dehydrogenase gene expression. However, although anaerobic alcohol dehydrogenase gene induction occurred in seedlings exposed to water-agar medium and in roots, related luminescence responses were absent. Upon return to normoxia, the luminescence of cotyledons, leaves, and roots dropped quickly, before increasing again in a Gd3+, La3+, ethyleneglycol-bis(beta-aminoethyl ether)-N,N'-tetraacetic acid-, and RR-sensitive fashion.

  18. Mutation of a Gene in the Fungus Leptosphaeria maculans Allows Increased Frequency of Penetration of Stomatal Apertures of Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    Candace E. Elliott; Harjono; Barbara J. Howlett

    2008-01-01

    Leptosphaeria maculans, a pathogen of Brassica napus, is unable to invade most wild-type accessions of Arabidopsis thaliana, although several mutants are susceptible. The infection pathway of L. maculans via a non-invasive inoculation method on A, thaliana Ires1 (undefined), pmr4-1 (defective in callose deposition), and pen1-1 and pen2-1 (defective in non-host responses to several pathogens) mutants is described. On wild types Col-0 and Ler-0, hyphae are generally arrested at stomatal apertures. A T-DNA insertional mutant of L. maculans (A22) that penetrates stomatal apertures of Col-0 and Ler-0 five to seven times more often than the wild-type isolate is described. The higher penetration frequency of isolate A22 is associated with an increased hypersensitive response, which includes callose deposition. Complementation analysis showed that the phenotype of this isolate is due to T-DNA insertion in an intronless gene denoted as ipa (increased penetration on Arabidopsis). This gene is predicted to encode a protein of 702 amino acids with best matches to hypothetical proteins in other filamentous ascomycetes. The ipa gene is expressed in the wild-type isolate at low levels in culture and during infection of A. thaliana and B. napus.

  19. Jasmonate controls late development stages of petal growth in Arabidopsis thaliana.

    Science.gov (United States)

    Brioudes, Florian; Joly, Caroline; Szécsi, Judit; Varaud, Emilie; Leroux, Julie; Bellvert, Floriant; Bertrand, Cédric; Bendahmane, Mohammed

    2009-12-01

    In Arabidopsis, four homeotic gene classes, A, B, C and E, are required for the patterning of floral organs. However, very little is known about how the activity of these master genes is translated into regulatory processes leading to specific growth patterns and the formation of organs with specific shapes and sizes. Previously we showed that the transcript variant BPEp encodes a bHLH transcription factor that is involved in limiting petal size by controlling post-mitotic cell expansion. Here we show that the phytohormone jasmonate is required for control of BPEp expression. Expression of BPEp was negatively regulated in opr3 mutant flowers that are deficient in jasmonate synthesis. Moreover, the expression of BPEp was restored in opr3 flowers following exogenous jasmonate treatments. Expression of the second transcript variant BPEub, which originates from the same gene as BPEp via an alternative splicing event, was not affected, indicating that BPEp accumulation triggered by jasmonate occurs at the post-transcriptional level. Consistent with these data, opr3 exhibited an increase in petal size as a result of increased cell size, as well as a modified vein pattern, phenotypes that are similar to those of the bpe-1 mutant. Furthermore, exogenous treatments with jasmonate rescued petal phenotypes associated with loss of function of OPR3. Our data demonstrate that jasmonate signaling downstream of OPR3 is involved in the control of cell expansion and in limiting petal size, and that BPEp is a downstream target that functions as a component mediating jasmonate signaling during petal growth. PMID:19765234

  20. 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