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Sample records for higher plant arabidopsis

  1. Metabolism of ibuprofen in higher plants: A model Arabidopsis thaliana cell suspension culture system

    Czech Academy of Sciences Publication Activity Database

    Maršík, Petr; Šíša, Miroslav; Lacina, O.; Moťková, Kateřina; Langhansová, Lenka; Rezek, Jan; Vaněk, Tomáš

    2017-01-01

    Roč. 220, JAN (2017), s. 383-392 ISSN 0269-7491 R&D Projects: GA ČR(CZ) GA14-22593S Grant - others:European Regional Development Fund(XE) CZ.2.16/3.1.00/24014 Institutional support: RVO:61389030 Keywords : Arabidopsis thaliana * Ibuprofen * Metabolism * Plant cells * Sequestration Subject RIV: CE - Biochemistry OBOR OECD: Plant sciences, botany Impact factor: 5.099, year: 2016

  2. DNA repair and recombination in higher plants: insights from comparative genomics of arabidopsis and rice

    Directory of Open Access Journals (Sweden)

    Choudhury Swarup

    2010-07-01

    Full Text Available Abstract Background The DNA repair and recombination (DRR proteins protect organisms against genetic damage, caused by environmental agents and other genotoxic agents, by removal of DNA lesions or helping to abide them. Results We identified genes potentially involved in DRR mechanisms in Arabidopsis and rice using similarity searches and conserved domain analysis against proteins known to be involved in DRR in human, yeast and E. coli. As expected, many of DRR genes are very similar to those found in other eukaryotes. Beside these eukaryotes specific genes, several prokaryotes specific genes were also found to be well conserved in plants. In Arabidopsis, several functionally important DRR gene duplications are present, which do not occur in rice. Among DRR proteins, we found that proteins belonging to the nucleotide excision repair pathway were relatively more conserved than proteins needed for the other DRR pathways. Sub-cellular localization studies of DRR gene suggests that these proteins are mostly reside in nucleus while gene drain in between nucleus and cell organelles were also found in some cases. Conclusions The similarities and dissimilarities in between plants and other organisms' DRR pathways are discussed. The observed differences broaden our knowledge about DRR in the plants world, and raises the potential question of whether differentiated functions have evolved in some cases. These results, altogether, provide a useful framework for further experimental studies in these organisms.

  3. DNA repair and recombination in higher plants: insights from comparative genomics of Arabidopsis and rice.

    Science.gov (United States)

    Singh, Sanjay K; Roy, Sujit; Choudhury, Swarup Roy; Sengupta, Dibyendu N

    2010-07-21

    The DNA repair and recombination (DRR) proteins protect organisms against genetic damage, caused by environmental agents and other genotoxic agents, by removal of DNA lesions or helping to abide them. We identified genes potentially involved in DRR mechanisms in Arabidopsis and rice using similarity searches and conserved domain analysis against proteins known to be involved in DRR in human, yeast and E. coli. As expected, many of DRR genes are very similar to those found in other eukaryotes. Beside these eukaryotes specific genes, several prokaryotes specific genes were also found to be well conserved in plants. In Arabidopsis, several functionally important DRR gene duplications are present, which do not occur in rice. Among DRR proteins, we found that proteins belonging to the nucleotide excision repair pathway were relatively more conserved than proteins needed for the other DRR pathways. Sub-cellular localization studies of DRR gene suggests that these proteins are mostly reside in nucleus while gene drain in between nucleus and cell organelles were also found in some cases. The similarities and dissimilarities in between plants and other organisms' DRR pathways are discussed. The observed differences broaden our knowledge about DRR in the plants world, and raises the potential question of whether differentiated functions have evolved in some cases. These results, altogether, provide a useful framework for further experimental studies in these organisms.

  4. Towards systems biology of the gravity response of higher plants -multiscale analysis of Arabidopsis thaliana root growth

    Science.gov (United States)

    Palme, Klaus; Aubry, D.; Bensch, M.; Schmidt, T.; Ronneberger, O.; Neu, C.; Li, X.; Wang, H.; Santos, F.; Wang, B.; Paponov, I.; Ditengou, F. A.; Teale, W. T.; Volkmann, D.; Baluska, F.; Nonis, A.; Trevisan, S.; Ruperti, B.; Dovzhenko, A.

    Gravity plays a fundamental role in plant growth and development. Up to now, little is known about the molecular organisation of the signal transduction cascades and networks which co-ordinate gravity perception and response. By using an integrated systems biological approach, a systems analysis of gravity perception and the subsequent tightly-regulated growth response is planned in the model plant Arabidopsis thaliana. This approach will address questions such as: (i) what are the components of gravity signal transduction pathways? (ii) what are the dynamics of these components? (iii) what is their spatio-temporal regulation in different tis-sues? Using Arabidopsis thaliana as a model-we use root growth to obtain insights in the gravity response. New techniques enable identification of the individual genes affected by grav-ity and further integration of transcriptomics and proteomics data into interaction networks and cell communication events that operate during gravitropic curvature. Using systematic multiscale analysis we have identified regulatory networks consisting of transcription factors, the protein degradation machinery, vesicle trafficking and cellular signalling during the gravire-sponse. We developed approach allowing to incorporate key features of the root system across all relevant spatial and temporal scales to describe gene-expression patterns and correlate them with individual gene and protein functions. Combination of high-resolution microscopy and novel computational tools resulted in development of the root 3D model in which quantitative descriptions of cellular network properties and of multicellular interactions important in root growth and gravitropism can be integrated for the first time.

  5. Diuretics Prime Plant Immunity in Arabidopsis thaliana

    Science.gov (United States)

    Noutoshi, Yoshiteru; Ikeda, Mika; Shirasu, Ken

    2012-01-01

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

  6. Radiosensitivity of higher plants

    International Nuclear Information System (INIS)

    Feng Zhijie

    1992-11-01

    The general views on radiosensitivity of higher plants have been introduced from published references. The radiosensitivity varies with species, varieties and organs or tissues. The main factors of determining the radiosensitivity in different species are nucleus volume, chromosome volume, DNA content and endogenous compounds. The self-repair ability of DNA damage and chemical group of biological molecules, such as -SH thiohydroxy of proteins, are main factors to determine the radiosensitivity in different varieties. The moisture, oxygen, temperature radiosensitizer and protector are important external factors for radiosensitivity. Both the multiple target model and Chadwick-Leenhouts model are ideal mathematical models for describing the radiosensitivity of higher plants and the latter has more clear significance in biology

  7. Molecular and functional analysis of phosphomannomutase (PMM) from higher plants and genetic evidence for the involvement of PMM in ascorbic acid biosynthesis in Arabidopsis and Nicotiana benthamiana

    DEFF Research Database (Denmark)

    Qian, W; Yu, C; Qin, H

    2007-01-01

    , soybean, tomato, rice and wheat. Amino acid sequence comparisons indicated that plant PMM proteins exhibited significant identity to their fungal and mammalian orthologs. In line with the similarity in primary structure, plant PMM complemented the sec53-6 temperature sensitive mutant of Saccharomyces...... was constitutively expressed in both vegetative and reproductive organs. Reducing the PMM expression level through virus-induced gene silencing caused a substantial decrease in ascorbic acid (AsA) content in N. benthamiana leaves. Conversely, raising the PMM expression level in N. benthamiana using viral......-vector-mediated ectopic expression led to a 20-50% increase in AsA content. Consistent with this finding, transgenic expression of an AtPMM-GFP fusion protein in Arabidopsis also increased AsA content by 25-33%. Collectively, this study improves our understanding on the molecular and functional properties of plant PMM...

  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. The development of Arabidopsis as a plant model

    NARCIS (Netherlands)

    Koornneef, M.; Meinke, D.W.

    2010-01-01

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

  10. Metabolic changes in Arabidopsis thaliana plants overexpressing chalcone synthase

    NARCIS (Netherlands)

    Dao, Thi Thanh Hien

    2010-01-01

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

  11. Gene Discovery and Functional Analyses in the Model Plant Arabidopsis

    DEFF Research Database (Denmark)

    Feng, Cai-ping; Mundy, J.

    2006-01-01

    The present mini-review describes newer methods and strategies, including transposon and T-DNA insertions, TILLING, Deleteagene, and RNA interference, to functionally analyze genes of interest in the model plant Arabidopsis. The relative advantages and disadvantages of the systems are also discus...

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

    Science.gov (United States)

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

    2004-01-01

    Arabidopsis thaliana is the most widely studied model plant. Functional genomics is intensively underway in many laboratories worldwide. Beyond the basic annotation of the primary sequence data, the annotated genetic elements of Arabidopsis must be linked to diverse biological data and higher order information such as metabolic or regulatory pathways. The MIPS Arabidopsis thaliana database MAtDB aims to provide a comprehensive resource for Arabidopsis as a genome model that serves as a primary reference for research in plants and is suitable for transfer of knowledge to other plants, especially crops. The genome sequence as a common backbone serves as a scaffold for the integration of data, while, in a complementary effort, these data are enhanced through the application of state-of-the-art bioinformatics tools. This information is visualized on a genome-wide and a gene-by-gene basis with access both for web users and applications. This report updates the information given in a previous report and provides an outlook on further developments. The MAtDB web interface can be accessed at http://mips.gsf.de/proj/thal/db. PMID:14681437

  13. Cellulose biosynthesis in higher plants

    Directory of Open Access Journals (Sweden)

    Krystyna Kudlicka

    2014-01-01

    Full Text Available Knowledge of the control and regulation of cellulose synthesis is fundamental to an understanding of plant development since cellulose is the primary structural component of plant cell walls. In vivo, the polymerization step requires a coordinated transport of substrates across membranes and relies on delicate orientations of the membrane-associated synthase complexes. Little is known about the properties of the enzyme complexes, and many questions about the biosynthesis of cell wall components at the cell surface still remain unanswered. Attempts to purify cellulose synthase from higher plants have not been successful because of the liability of enzymes upon isolation and lack of reliable in vitro assays. Membrane preparations from higher plant cells incorporate UDP-glucose into a glucan polymer, but this invariably turns out to be predominantly β -1,3-linked rather than β -1,4-linked glucans. Various hypotheses have been advanced to explain this phenomenon. One idea is that callose and cellulose-synthase systems are the same, but cell disruption activates callose synthesis preferentially. A second concept suggests that a regulatory protein as a part of the cellulose-synthase complex is rapidly degraded upon cell disruption. With new methods of enzyme isolation and analysis of the in vitro product, recent advances have been made in the isolation of an active synthase from the plasma membrane whereby cellulose synthase was separated from callose synthase.

  14. Mining the plant-herbivore interface with a leafmining Drosophila of Arabidopsis

    Science.gov (United States)

    Whiteman, Noah K.; Groen, Simon C.; Chevasco, Daniela; Bear, Ashley; Beckwith, Noor; Gregory, T. Ryan; Denoux, Carine; Mammarella, Nicole; Ausubel, Frederick M.; Pierce, Naomi E.

    2010-01-01

    Experimental infections of Arabidopsis thaliana (Arabidopsis) with genomically characterized plant pathogens such as Pseudomonas syringae have facilitated dissection of canonical eukaryotic defense pathways and parasite virulence factors. Plants are also attacked by herbivorous insects, and the development of an ecologically relevant genetic model herbivore that feeds on Arabidopsis will enable the parallel dissection of host defense and reciprocal resistance pathways such as those involved in xenobiotic metabolism. An ideal candidate is Scaptomyza flava, a drosophilid fly whose leafmining larvae are true herbivores that can be found in nature feeding on Arabidopsis and other crucifers. Here we describe the eukaryotic life cycle of S. flava on Arabidopsis, and use multiple approaches to characterize the response of Arabidopsis to S. flava attack. Oviposition choice tests and growth performance assays on different Arabidopsis ecotypes, defense-related mutants, and hormone and chitin-treated plants revealed significant differences in host preference and variation in larval performance across Arabidopsis accessions. The jasmonate (JA) and glucosinolate pathways in Arabidopsis are important in mediating quantitative resistance against S. flava, and priming with JA or chitin resulted in increased resistance. Expression of xenobiotic detoxification genes was reduced in S. flava larvae reared on Arabidopsis JA signaling mutants, and increased in plants pre-treated with chitin. These results and future research directions are discussed in the context of developing a genetic model system to analyze insect/plant interactions. PMID:21073583

  15. Human intrinsic factor expressed in the plant Arabidopsis thaliana

    DEFF Research Database (Denmark)

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

    2003-01-01

    and 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...... to 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.......Intrinsic factor (IF) is the gastric protein that promotes the intestinal uptake of vitamin B12. Gastric IF from animal sources is used in diagnostic tests and in vitamin pills. However, administration of animal IF to humans becomes disadvantageous because of possible pathogenic transmission...

  16. Human intrinsic factor expressed in the plant Arabidopsis thaliana

    DEFF Research Database (Denmark)

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

    2003-01-01

    and 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......Intrinsic factor (IF) is the gastric protein that promotes the intestinal uptake of vitamin B12. Gastric IF from animal sources is used in diagnostic tests and in vitamin pills. However, administration of animal IF to humans becomes disadvantageous because of possible pathogenic transmission...... 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...

  17. Computational identification of candidate nucleotide cyclases in higher plants

    KAUST Repository

    Wong, Aloysius Tze

    2013-09-03

    In higher plants guanylyl cyclases (GCs) and adenylyl cyclases (ACs) cannot be identified using BLAST homology searches based on annotated cyclic nucleotide cyclases (CNCs) of prokaryotes, lower eukaryotes, or animals. The reason is that CNCs are often part of complex multifunctional proteins with different domain organizations and biological functions that are not conserved in higher plants. For this reason, we have developed CNC search strategies based on functionally conserved amino acids in the catalytic center of annotated and/or experimentally confirmed CNCs. Here we detail this method which has led to the identification of >25 novel candidate CNCs in Arabidopsis thaliana, several of which have been experimentally confirmed in vitro and in vivo. We foresee that the application of this method can be used to identify many more members of the growing family of CNCs in higher plants. © Springer Science+Business Media New York 2013.

  18. Chromosomal replicons of higher plants

    International Nuclear Information System (INIS)

    Van't Hof, J.

    1987-01-01

    This brief discussion of replicons of higher plants offers a glimpse into the properties of chromosomal DNA replication. It gives evidence that the S phase of unrelated plant species is comprised of temporally ordered replicon families that increase in number with genome size. This orderly process, which assures a normal inheritance of genetic material to recipient daughter cells, is maintained at the level of replicon clusters by two mutually exclusive mechanisms, one involving the rate at which single replicons replicate their allotment of DNA, and another by means of the tempo-pause. The same two mechanisms are used by cells to alter the pattern of chromosomal DNA replication just prior to and during normal development. Both mechanisms are genetically determined and produce genetic effects when disturbed of disrupted by additional non-conforming DNAs. Further insight into how these two mechanisms operate requires more molecular information about the nature of replicons and the factors that govern when a replicon family replicates. Plant material is a rich and ideal source for this information just awaiting exploitation. 63 refs

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

    NARCIS (Netherlands)

    Wintermans, Paul C A; Bakker, Peter A H M; Pieterse, Corné M J

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

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

    NARCIS (Netherlands)

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

    2016-01-01

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

  1. Mighty Dwarfs: Arabidopsis autoimmune mutants and their usages in genetic dissection of plant immunity

    Directory of Open Access Journals (Sweden)

    Rowan Wersch

    2016-11-01

    Full Text Available Plants lack the adaptive immune system possessed by mammals. Instead they rely on innate immunity to defend against pathogen attacks. Genomes of higher plants encode a large number of plant immune receptors belonging to different protein families, which are involved in the detection of pathogens and activation of downstream defense pathways. Plant immunity is tightly controlled to avoid activation of defense responses in the absence of pathogens, as failure to do so can lead to autoimmunity that compromises plant growth and development. Many autoimmune mutants have been reported, most of which are associated with dwarfism and often spontaneous cell death. In this review, we summarize previously reported Arabidopsis autoimmune mutants, categorizing them based on their functional groups. We also discuss how their obvious morphological phenotypes make them ideal tools for epistatic analysis and suppressor screens, and summarize genetic screens that have been carried out in various autoimmune mutant backgrounds.

  2. System identification of the Arabidopsis plant circadian system

    Science.gov (United States)

    Foo, Mathias; Somers, David E.; Kim, Pan-Jun

    2015-02-01

    The circadian system generates an endogenous oscillatory rhythm that governs the daily activities of organisms in nature. It offers adaptive advantages to organisms through a coordination of their biological functions with the optimal time of day. In this paper, a model of the circadian system in the plant Arabidopsis (species thaliana) is built by using system identification techniques. Prior knowledge about the physical interactions of the genes and the proteins in the plant circadian system is incorporated in the model building exercise. The model is built by using primarily experimentally-verified direct interactions between the genes and the proteins with the available data on mRNA and protein abundances from the circadian system. Our analysis reveals a great performance of the model in predicting the dynamics of the plant circadian system through the effect of diverse internal and external perturbations (gene knockouts and day-length changes). Furthermore, we found that the circadian oscillatory rhythm is robust and does not vary much with the biochemical parameters except those of a light-sensitive protein P and a transcription factor TOC1. In other words, the circadian rhythmic profile is largely a consequence of the network's architecture rather than its particular parameters. Our work suggests that the current experimental knowledge of the gene-to-protein interactions in the plant Arabidopsis, without considering any additional hypothetical interactions, seems to suffice for system-level modeling of the circadian system of this plant and to present an exemplary platform for the control of network dynamics in complex living organisms.

  3. Accumulation and phytotoxicity of perfluorooctanoic acid in the model plant species Arabidopsis thaliana

    International Nuclear Information System (INIS)

    Yang, Xinping; Ye, Chengchen; Liu, Yu; Zhao, Fang-Jie

    2015-01-01

    Perfluorooctanoic acid (PFOA) is widely used in the manufacture of many industrial and household products. To assess the potential environmental risk of PFOA, its accumulation, translocation and phytotoxic effects were investigated using the model plant species Arabidopsis thaliana. Exposure to 18 μM PFOA-F in agar plates did not affect plant growth, but 181–1811 μM PFOA-F inhibited root and shoot growth. PFOA was more phytotoxic on shoot growth than NaF at the equivalent F concentration, with the latter having 3.9–7.6 times higher EC50 for shoot biomass than PFOA. PFOA was efficiently translocated from roots to shoots, where it existed as intact PFOA molecules without transformation evidenced by the 19 F NMR spectra. PFOA caused a significant increase in the concentration of H 2 O 2 and malondialdehyde (MDA) in shoots, indicating that oxidative stress is a likely cause of PFOA phytotoxicity. - Highlights: • PFOA is more phytotoxic on shoot growth than NaF at the equivalent F concentration. • PFOA is readily taken up and translocated from roots to shoots. • PFOA exists as intact molecules without transformation in Arabidopsis shoots. • PFOA causes oxidative stress in Arabidopsis shoots. - Perfluorooctanoic acid causes oxidative stress and is more phytotoxic on shoot growth than inorganic fluoride at the equivalent F concentration.

  4. The ERECTA gene regulates plant transpiration efficiency in Arabidopsis.

    Science.gov (United States)

    Masle, Josette; Gilmore, Scott R; Farquhar, Graham D

    2005-08-11

    Assimilation of carbon by plants incurs water costs. In the many parts of the world where water is in short supply, plant transpiration efficiency, the ratio of carbon fixation to water loss, is critical to plant survival, crop yield and vegetation dynamics. When challenged by variations in their environment, plants often seem to coordinate photosynthesis and transpiration, but significant genetic variation in transpiration efficiency has been identified both between and within species. This has allowed plant breeders to develop effective selection programmes for the improved transpiration efficiency of crops, after it was demonstrated that carbon isotopic discrimination, Delta, of plant matter was a reliable and sensitive marker negatively related to variation in transpiration efficiency. However, little is known of the genetic controls of transpiration efficiency. Here we report the isolation of a gene that regulates transpiration efficiency, ERECTA. We show that ERECTA, a putative leucine-rich repeat receptor-like kinase (LRR-RLK) known for its effects on inflorescence development, is a major contributor to a locus for Delta on Arabidopsis chromosome 2. Mechanisms include, but are not limited to, effects on stomatal density, epidermal cell expansion, mesophyll cell proliferation and cell-cell contact.

  5. Abscisic acid and transpiration rate are involved in the response to boron toxicity in Arabidopsis plants.

    Science.gov (United States)

    Macho-Rivero, Miguel Ángel; Camacho-Cristóbal, Juan José; Herrera-Rodríguez, María Begoña; Müller, Maren; Munné-Bosch, Sergi; González-Fontes, Agustín

    2017-05-01

    Boron (B) is an essential microelement for vascular plant development, but its toxicity is a major problem affecting crop yields in arid and semi-arid areas of the world. In the literature, several genes involved in abscisic acid (ABA) signalling and responses are upregulated in Arabidopsis roots after treatment with excess B. It is known that the AtNCED3 gene, which encodes a crucial enzyme for ABA biosynthesis, plays a key role in the plant response to drought stress. In this study, root AtNCED3 expression and shoot ABA content were rapidly increased in wild-type plants upon B-toxicity treatment. The Arabidopsis ABA-deficient nced3-2 mutant had higher transpiration rate, stomatal conductance and accumulated more B in their shoots than wild-type plants, facts that were associated with the lower levels of ABA in this mutant. However, in wild-type plants, B toxicity caused a significant reduction in stomatal conductance, resulting in a decreased transpiration rate. This response could be a mechanism to limit the transport of excess B from the roots to the leaves under B toxicity. In agreement with the higher transpiration rate of the nced3-2 mutant, this genotype showed an increased leaf B concentration and damage upon exposure to 5 mM B. Under B toxicity, ABA application decreased B accumulation in wild-type and nced3-2 plants. In summary, this work shows that excess B applied to the roots leads to rapid changes in AtNCED3 expression and gas exchange parameters that would contribute to restrain the B entry into the leaves, this effect being mediated by ABA. © 2016 Scandinavian Plant Physiology Society.

  6. Gene expression in plant lipid metabolism in Arabidopsis seedlings.

    Directory of Open Access Journals (Sweden)

    An-Shan Hsiao

    Full Text Available Events in plant lipid metabolism are important during seedling establishment. As it has not been experimentally verified whether lipid metabolism in 2- and 5-day-old Arabidopsis thaliana seedlings is diurnally-controlled, quantitative real-time PCR analysis was used to investigate the expression of target genes in acyl-lipid transfer, β-oxidation and triacylglycerol (TAG synthesis and hydrolysis in wild-type Arabidopsis WS and Col-0. In both WS and Col-0, ACYL-COA-BINDING PROTEIN3 (ACBP3, DIACYLGLYCEROL ACYLTRANSFERASE1 (DGAT1 and DGAT3 showed diurnal control in 2- and 5-day-old seedlings. Also, COMATOSE (CTS was diurnally regulated in 2-day-old seedlings and LONG-CHAIN ACYL-COA SYNTHETASE6 (LACS6 in 5-day-old seedlings in both WS and Col-0. Subsequently, the effect of CIRCADIAN CLOCK ASSOCIATED1 (CCA1 and LATE ELONGATED HYPOCOTYL (LHY from the core clock system was examined using the cca1lhy mutant and CCA1-overexpressing (CCA1-OX lines versus wild-type WS and Col-0, respectively. Results revealed differential gene expression in lipid metabolism between 2- and 5-day-old mutant and wild-type WS seedlings, as well as between CCA1-OX and wild-type Col-0. Of the ACBPs, ACBP3 displayed the most significant changes between cca1lhy and WS and between CCA1-OX and Col-0, consistent with previous reports that ACBP3 is greatly affected by light/dark cycling. Evidence of oil body retention in 4- and 5-day-old seedlings of the cca1lhy mutant in comparison to WS indicated the effect of cca1lhy on storage lipid reserve mobilization. Lipid profiling revealed differences in primary lipid metabolism, namely in TAG, fatty acid methyl ester and acyl-CoA contents amongst cca1lhy, CCA1-OX, and wild-type seedlings. Taken together, this study demonstrates that lipid metabolism is subject to diurnal regulation in the early stages of seedling development in Arabidopsis.

  7. Iron Deficiency Prolongs Seed Dormancy in Arabidopsis Plants

    Directory of Open Access Journals (Sweden)

    Irene Murgia

    2017-12-01

    Full Text Available The understanding of seed dormancy, germination and longevity are important goals in plant biology, with relevant applications for agriculture, food industry and also human nutrition. Reactive Oxygen Species (ROS are key molecules involved in the release of dormancy, when their concentrations fall within the so called ‘oxidative window.’ The mechanisms of ROS distribution and sensing in seeds, from dormant to germinating ones, still need elucidation. Also, the impact of iron (Fe deficiency on seed dormancy is still unexplored; this is surprising, given the known pro-oxidant role of Fe when in a free form. We provide evidence of a link between plant Fe nutrition and dormancy of progeny seeds by using different Arabidopsis ecotypes and mutants with different dormancy strengths grown in control soil or under severe Fe deficiency. The latter condition extends the dormancy in several genotypes. The focus on the mechanisms involved in the Fe deficiency-dependent alteration of dormancy and longevity promises to be a key issue in seed (redox biology.

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

    Directory of Open Access Journals (Sweden)

    Yuan Joshua S

    2008-08-01

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

  9. Overexpression of cotton RAV1 gene in Arabidopsis confers transgenic plants high salinity and drought sensitivity.

    Science.gov (United States)

    Li, Xiao-Jie; Li, Mo; Zhou, Ying; Hu, Shan; Hu, Rong; Chen, Yun; Li, Xue-Bao

    2015-01-01

    RAV (related to ABI3/VP1) protein containing an AP2 domain in the N-terminal region and a B3 domain in the C-terminal region, which belongs to AP2 transcription factor family, is unique in higher plants. In this study, a gene (GhRAV1) encoding a RAV protein of 357 amino acids was identified in cotton (Gossypium hirsutum). Transient expression analysis of the eGFP:GhRAV1 fusion genes in tobacco (Nicotiana tabacum) epidermal cells revealed that GhRAV1 protein was localized in the cell nucleus. Quantitative RT-PCR analysis indicated that expression of GhRAV1 in cotton is induced by abscisic acid (ABA), NaCl and polyethylene glycol (PEG). Overexpression of GhRAV1 in Arabidopsis resulted in plant sensitive to ABA, NaCl and PEG. With abscisic acid (ABA) treatment, seed germination and green seedling rates of the GhRAV1 transgenic plants were remarkably lower than those of wild type. In the presence of NaCl, the seed germination and seedling growth of the GhRAV1 transgenic lines were inhibited greater than those of wild type. And chlorophyll content and maximum photochemical efficiency of the transgenic plants were significantly lower than those of wild type. Under drought stress, the GhRAV1 transgenic plants displayed more severe wilting than wild type. Furthermore, expressions of the stress-related genes were altered in the GhRAV1 transgenic Arabidopsis plants under high salinity and drought stresses. Collectively, our data suggested that GhRAV1 may be involved in response to high salinity and drought stresses through regulating expressions of the stress-related genes during cotton development.

  10. Synthesis of hydroxylated sterols in transgenic Arabidopsis plants alters growth and steroid metabolism.

    Science.gov (United States)

    Beste, Lisa; Nahar, Nurun; Dalman, Kerstin; Fujioka, Shozo; Jonsson, Lisbeth; Dutta, Paresh C; Sitbon, Folke

    2011-09-01

    To explore mechanisms in plant sterol homeostasis, we have here increased the turnover of sterols in Arabidopsis (Arabidopsis thaliana) and potato (Solanum tuberosum) plants by overexpressing four mouse cDNA encoding cholesterol hydroxylases (CHs), hydroxylating cholesterol at the C-7, C-24, C-25, or C-27 positions. Compared to the wild type, the four types of Arabidopsis transformant showed varying degrees of phenotypic alteration, the strongest one being in CH25 lines, which were dark-green dwarfs resembling brassinosteroid-related mutants. Gas chromatography-mass spectrometry analysis of extracts from wild-type Arabidopsis plants revealed trace levels of α and β forms of 7-hydroxycholesterol, 7-hydroxycampesterol, and 7-hydroxysitosterol. The expected hydroxycholesterol metabolites in CH7-, CH24-, and CH25 transformants were identified and quantified using gas chromatography-mass spectrometry. Additional hydroxysterol forms were also observed, particularly in CH25 plants. In CH24 and CH25 lines, but not in CH7 ones, the presence of hydroxysterols was correlated with a considerable alteration of the sterol profile and an increased sterol methyltransferase activity in microsomes. Moreover, CH25 lines contained clearly reduced levels of brassinosteroids, and displayed an enhanced drought tolerance. Equivalent transformations of potato plants with the CH25 construct increased hydroxysterol levels, but without the concomitant alteration of growth and sterol profiles observed in Arabidopsis. The results suggest that an increased hydroxylation of cholesterol and/or other sterols in Arabidopsis triggers compensatory processes, acting to maintain sterols at adequate levels.

  11. Radiation hormesis in higher plants

    International Nuclear Information System (INIS)

    Kim, Jae Sung

    1996-03-01

    The most remarkable aspect in the hormesis law is that low dose of harmful agents can produce effect that are diametrically opposite to the effect found with high doses of the same agent. Minute quantities of a harmful agent bring about very small change in the organism and control mechanisms appear to subjugate normal processes to place the organism in a state of alert and repair. The stimulated organism is more responsive to changes in environmental factors than it did before being alerted. Routine functions, including repair and defense, have priority for available energy and material. The alerted organism utilizes nutrients more efficiently, grows faster, shows improved defense reactions, matures faster, reproduces more effectively, has less disease, and lives longer. Accelerated germination, sprouting, growth, development, blooming and ripening, and increased crop yield and resistance to disease are found in plants. Another concept supported by the data is that low doses of ionizing radiation provide increased resistance to subsequent high doses of radiation. The hormesis varies with subject plant, variety, state of seed, environmental and cultural conditions, physiologic function measured, dose rate and total exposure. The results of hormesis are less consistently found, probably due to the great number of uncontrolled variables in the experiments. The general dosage for radiation hormesis in about 100 (10 to 1,000) times ambient or 100 (10 to 1,000) times less than a definitely harmful dose, but these must be modified to the occasion. Although little is known about most mechanisms of hormesis reaction, overcompensation of repair mechanism is offered as on mechanism. Radiation hormesis can provide more efficient use of resources, maximum production of foods, and increased health by the use of ionizing radiation as a useful tool in our technologic society. Efficient utilization of nature's resources demands support to explore the practical application of

  12. Radiation hormesis in higher plants

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Sung [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1996-03-01

    The most remarkable aspect in the hormesis law is that low dose of harmful agents can produce effect that are diametrically opposite to the effect found with high doses of the same agent. Minute quantities of a harmful agent bring about very small change in the organism and control mechanisms appear to subjugate normal processes to place the organism in a state of alert and repair. The stimulated organism is more responsive to changes in environmental factors than it did before being alerted. Routine functions, including repair and defense, have priority for available energy and material. The alerted organism utilizes nutrients more efficiently, grows faster, shows improved defense reactions, matures faster, reproduces more effectively, has less disease, and lives longer. Accelerated germination, sprouting, growth, development, blooming and ripening, and increased crop yield and resistance to disease are found in plants. Another concept supported by the data is that low doses of ionizing radiation provide increased resistance to subsequent high doses of radiation. The hormesis varies with subject plant, variety, state of seed, environmental and cultural conditions, physiologic function measured, dose rate and total exposure. The results of hormesis are less consistently found, probably due to the great number of uncontrolled variables in the experiments. The general dosage for radiation hormesis in about 100 times ambient or 100 times less than a definitely harmful dose, but these must be modified to the occasion. Although little is known about most mechanisms of hormesis reaction, overcompensation of repair mechanism is offered as on mechanism. Radiation hormesis can provide more efficient use of resources, maximum production of foods, and increased health by the use of ionizing radiation as a useful tool in our technologic society. Efficient utilization of nature`s resources demands support to explore the practical application of radiation hormesis.

  13. Dragon TIS Spotter: An Arabidopsis-derived predictor of translation initiation sites in plants

    KAUST Repository

    Magana-Mora, Arturo; Ashoor, Haitham; Jankovic, Boris R.; Kamau, Allan; Awara, Karim; Chowdhary, Rajesh; Archer, John A.C.; Bajic, Vladimir B.

    2012-01-01

    In higher eukaryotes, the identification of translation initiation sites (TISs) has been focused on finding these signals in cDNA or mRNA sequences. Using Arabidopsis thaliana (A.t.) information, we developed a prediction tool for signals within genomic sequences of plants that correspond to TISs. Our tool requires only genome sequence, not expressed sequences. Its sensitivity/specificity is for A.t. (90.75%/92.2%), for Vitis vinifera (66.8%/94.4%) and for Populus trichocarpa (81.6%/94.4%), which suggests that our tool can be used in annotation of different plant genomes. We provide a list of features used in our model. Further study of these features may improve our understanding of mechanisms of the translation initiation. The Author(s) 2012. Published by Oxford University Press.

  14. Dragon TIS Spotter: An Arabidopsis-derived predictor of translation initiation sites in plants

    KAUST Repository

    Magana-Mora, Arturo

    2012-10-30

    In higher eukaryotes, the identification of translation initiation sites (TISs) has been focused on finding these signals in cDNA or mRNA sequences. Using Arabidopsis thaliana (A.t.) information, we developed a prediction tool for signals within genomic sequences of plants that correspond to TISs. Our tool requires only genome sequence, not expressed sequences. Its sensitivity/specificity is for A.t. (90.75%/92.2%), for Vitis vinifera (66.8%/94.4%) and for Populus trichocarpa (81.6%/94.4%), which suggests that our tool can be used in annotation of different plant genomes. We provide a list of features used in our model. Further study of these features may improve our understanding of mechanisms of the translation initiation. The Author(s) 2012. Published by Oxford University Press.

  15. The sunflower transcription factor HaHB11 improves yield, biomass and tolerance to flooding in transgenic Arabidopsis plants.

    Science.gov (United States)

    Cabello, Julieta V; Giacomelli, Jorge I; Piattoni, Claudia V; Iglesias, Alberto A; Chan, Raquel L

    2016-03-20

    HaHB11 is a member of the sunflower homeodomain-leucine zipper I subfamily of transcription factors. The analysis of a sunflower microarray hybridized with RNA from HaHB11-transformed leaf-disks indicated the regulation of many genes encoding enzymes from glycolisis and fermentative pathways. A 1300bp promoter sequence, fused to the GUS reporter gene, was used to transform Arabidopsis plants showing an induction of expression after flooding treatments, concurrently with HaHB11 regulation by submergence in sunflower. Arabidopsis transgenic plants expressing HaHB11 under the control of the CaMV 35S promoter and its own promoter were obtained and these plants exhibited significant increases in rosette and stem biomass. All the lines produced more seeds than controls and particularly, those of high expression level doubled seeds yield. Transgenic plants also showed tolerance to flooding stress, both to submergence and waterlogging. Carbohydrates contents were higher in the transgenics compared to wild type and decreased less after submergence treatments. Finally, transcript levels of selected genes involved in glycolisis and fermentative pathways as well as the corresponding enzymatic activities were assessed both, in sunflower and transgenic Arabidopsis plants, before and after submergence. Altogether, the present work leads us to propose HaHB11 as a biotechnological tool to improve crops yield, biomass and flooding tolerance. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Adaptive diversification of growth allometry in the plant Arabidopsis thaliana.

    Science.gov (United States)

    Vasseur, François; Exposito-Alonso, Moises; Ayala-Garay, Oscar J; Wang, George; Enquist, Brian J; Vile, Denis; Violle, Cyrille; Weigel, Detlef

    2018-03-27

    Seed plants vary tremendously in size and morphology; however, variation and covariation in plant traits may be governed, at least in part, by universal biophysical laws and biological constants. Metabolic scaling theory (MST) posits that whole-organismal metabolism and growth rate are under stabilizing selection that minimizes the scaling of hydrodynamic resistance and maximizes the scaling of resource uptake. This constrains variation in physiological traits and in the rate of biomass accumulation, so that they can be expressed as mathematical functions of plant size with near-constant allometric scaling exponents across species. However, the observed variation in scaling exponents calls into question the evolutionary drivers and the universality of allometric equations. We have measured growth scaling and fitness traits of 451 Arabidopsis thaliana accessions with sequenced genomes. Variation among accessions around the scaling exponent predicted by MST was correlated with relative growth rate, seed production, and stress resistance. Genomic analyses indicate that growth allometry is affected by many genes associated with local climate and abiotic stress response. The gene with the strongest effect, PUB4 , has molecular signatures of balancing selection, suggesting that intraspecific variation in growth scaling is maintained by opposing selection on the trade-off between seed production and abiotic stress resistance. Our findings suggest that variation in allometry contributes to local adaptation to contrasting environments. Our results help reconcile past debates on the origin of allometric scaling in biology and begin to link adaptive variation in allometric scaling to specific genes. Copyright © 2018 the Author(s). Published by PNAS.

  17. Identification and Characterization of Novel Plant Adenylate Cyclases – The Arabidopsis Thaliana Potassium Uptake Permeases

    KAUST Repository

    Al-Younis, Inas M.

    2018-05-01

    Adenylyl Cyclases (ACs) catalyze the formation of the key universal second messenger adenosine 3’, 5’-cyclic monophosphate (cAMP) from adenosine 5’- triphosphate. Cyclic AMP participates in several signal transduction pathways and is present in bacteria and higher and lower eukaryotes including higher plants. Previous studies in plants have shown a role for cAMP in signal transduction during e.g. the cell cycle, elongation of the pollen tube and stimulation of protein kinase activity. More recently cAMP has been shown to play a role in stress responses. Interestingly, cAMP has also been shown to regulate ion transport in plant cells. Here we used a similar strategy that led to the discovery of the first guanylyl cyclase in plants that was based on the alignment of conserved and functionally assigned amino acids in the catalytic centre of annotated nucleotide cyclases from lower and higher eukaryotes, to identify a novel candidate ACs in Arabidopsis (Arabidopsis thaliana K+ Uptake 5 and 7). ATKUP5 and 7 are homologous to K+ uptake permeases (KUPs) from bacteria and high-affinity K+ transporters (HAKs) from fungi. The AC activity was investigated by recombinantly expressing the ATKUP5 and 7 AC domain in vitro and by complementation of an E. coli AC mutant (cyaA). Furthermore, ATKUP5 was tested for its ability to functionally complement a yeast mutant deficient in Trk1 and Trk2 high affinity potassium uptake transporters. Site-mutagenesis in the AC domain was used to test the effect of both functions in each other. Furthermore, ATKUP5 was characterized electrophysiologically in HEK-293 cells to characterize the nature of this transporter. The localization of the ATKUP5 in Arabidopsis was examined using a Green Fluorescent Protein (GFP) fusion with the ATKUP5 to determine whether ATKUP5 is expressed at the plasma or tonoplast membrane. Arabiodpsis thaliana of the wild type, overexpressing ATKUP5 and atkup5 mutant lines were used to examine phenotypic differences.

  18. Overexpression of PSP1 enhances growth of transgenic Arabidopsis plants under ambient air conditions.

    Science.gov (United States)

    Han, Xiaofang; Peng, Keli; Wu, Haixia; Song, Shanshan; Zhu, Yerong; Bai, Yanling; Wang, Yong

    2017-07-01

    The importance of the phosphorylated pathway (PPSB) of L-serine (Ser) biosynthesis in plant growth and development has been demonstrated, but its specific role in leaves and interaction with photorespiration, the main leaf Ser biosynthetic pathway at daytime, are still unclear. To investigate whether changes in biosynthesis of Ser by the PPSB in leaves could have an impact on photorespiration and plant growth, we overexpressed PSP1, the last enzyme of this pathway, under control of the Cauliflower Mosaic Virus 35S promoter in Arabidopsis thaliana. Overexpressor plants grown in normal air displayed larger rosette diameter and leaf area as well as higher fresh and dry weight than the wild type. By contrast, no statistically significant differences to the wild type were observed when the overexpressor seedlings were transferred to elevated CO 2 , indicating a relationship between PSP1 overexpression and photorespiration. Additionally, the transgenic plants displayed higher photorespiration, an increase in CO 2 net-uptake and stronger expression in the light of genes encoding enzymes involved in photorespiration. We further demonstrated that expression of many genes involved in nitrogen assimilation was also promoted in leaves of transgenic plants and that leaf nitrate reductase activity increased in the light, too, although not in the dark. Our results suggest a close correlation between the function of PPSB and photorespiration, and also nitrogen metabolism in leaves.

  19. Analysis of plastid number, size, and distribution in Arabidopsis plants by light and fluorescence microscopy.

    Science.gov (United States)

    Pyke, Kevin

    2011-01-01

    Methods are described which allow one to observe chloroplasts in mesophyll cells from leaves of Arabidopsis, determine their number per cell, measure their area, and determine a value for chloroplast coverage inside mesophyll cells. Non-green plastids can also be imaged either by using staining, or by exploiting fluorescent proteins targeted to the plastid in non-green parts of the plant, such as the roots, in transgenic Arabidopsis.

  20. Structure of the higher plant light harvesting complex I: In vivo characterization and structural interdependence of the Lhca proteins

    NARCIS (Netherlands)

    Klimmek, F.; Ganeteg, U.; Ihalainen, J.A.; van Roon, H.; Jensen, P.E.; Scheller, H.V.; Dekker, J.P.; Jansson, S.

    2005-01-01

    We have investigated the structure of the higher plant light harvesting complex of photosystem I (LHCI) by analyzing PSI-LHCI particles isolated from a set of Arabidopsis plant lines, each lacking a specific Lhca (Lhca1-4) polypeptide. Functional antenna size measurements support the recent finding

  1. Arabidopsis thaliana: A model host plant to study plant-pathogen interaction using Chilean field isolates of Botrytis cinerea

    Directory of Open Access Journals (Sweden)

    JUAN GONZÁLEZ

    2006-01-01

    Full Text Available One of the fungal pathogens that causes more agriculture damage is Botrytis cinerea. Botrytis is a constant threat to crops because the fungus infects a wide range of host species, both native and cultivated. Furthermore, Botrytis persists on plant debris in and on the soil. Some of the most serious diseases caused by Botrytis include gray mold on vegetables and fruits, such as grapes and strawberries. Botrytis also causes secondary soft rot of fruits and vegetables during storage, transit and at the market. In many plant-pathogen interactions, resistance often is associated with the deposition of callose, accumulation of autofluorescent compounds, the synthesis and accumulation of salicylic acid as well as pathogenesis-related proteins. Arabidopsis thaliana has been used as a plant model to study plant-pathogen interaction. The genome of Arabidopsis has been completely sequenced and this plant serves as a good genetic and molecular model. In this study, we demonstrate that Chilean field isolates infect Arabidopsis thaliana and that Arabidopsis subsequently activates several defense response mechanisms associated with a hypersensitive response. Furthermore, we propose that Arabidopsis may be used as a model host species to analyze the diversity associated with infectivity among populations of Botrytis cinerea field isolates

  2. Roles of Arabidopsis WRKY3 and WRKY4 Transcription Factors in Plant Responses to Pathogens

    Directory of Open Access Journals (Sweden)

    Fan Baofang

    2008-06-01

    Full Text Available Abstract Background Plant WRKY DNA-binding transcription factors are involved in plant responses to biotic and abiotic responses. It has been previously shown that Arabidopsis WRKY3 and WRKY4, which encode two structurally similar WRKY transcription factors, are induced by pathogen infection and salicylic acid (SA. However, the role of the two WRKY transcription factors in plant disease resistance has not been directly analyzed. Results Both WRKY3 and WRKY4 are nuclear-localized and specifically recognize the TTGACC W-box sequences in vitro. Expression of WRKY3 and WRKY4 was induced rapidly by stress conditions generated by liquid infiltration or spraying. Stress-induced expression of WRKY4 was further elevated by pathogen infection and SA treatment. To determine directly their role in plant disease resistance, we have isolated T-DNA insertion mutants and generated transgenic overexpression lines for WRKY3 and WRKY4. Both the loss-of-function mutants and transgenic overexpression lines were examined for responses to the biotrophic bacterial pathogen Pseudomonas syringae and the necrotrophic fungal pathogen Botrytis cinerea. The wrky3 and wrky4 single and double mutants exhibited more severe disease symptoms and support higher fungal growth than wild-type plants after Botrytis infection. Although disruption of WRKY3 and WRKY4 did not have a major effect on plant response to P. syringae, overexpression of WRKY4 greatly enhanced plant susceptibility to the bacterial pathogen and suppressed pathogen-induced PR1 gene expression. Conclusion The nuclear localization and sequence-specific DNA-binding activity support that WRKY3 and WRKY4 function as transcription factors. Functional analysis based on T-DNA insertion mutants and transgenic overexpression lines indicates that WRKY3 and WRKY4 have a positive role in plant resistance to necrotrophic pathogens and WRKY4 has a negative effect on plant resistance to biotrophic pathogens.

  3. Nictaba Homologs from Arabidopsis thaliana Are Involved in Plant Stress Responses

    Directory of Open Access Journals (Sweden)

    Lore Eggermont

    2018-01-01

    Full Text Available Plants are constantly exposed to a wide range of environmental stresses, but evolved complicated adaptive and defense mechanisms which allow them to survive in unfavorable conditions. These mechanisms protect and defend plants by using different immune receptors located either at the cell surface or in the cytoplasmic compartment. Lectins or carbohydrate-binding proteins are widespread in the plant kingdom and constitute an important part of these immune receptors. In the past years, lectin research has focused on the stress-inducible lectins. The Nicotiana tabacum agglutinin, abbreviated as Nictaba, served as a model for one family of stress-related lectins. Here we focus on three non-chimeric Nictaba homologs from Arabidopsis thaliana, referred to as AN3, AN4, and AN5. Confocal microscopy of ArathNictaba enhanced green fluorescent protein (EGFP fusion constructs transiently expressed in N. benthamiana or stably expressed in A. thaliana yielded fluorescence for AN4 and AN5 in the nucleus and the cytoplasm of the plant cell, while fluorescence for AN3 was only detected in the cytoplasm. RT-qPCR analysis revealed low expression for all three ArathNictabas in different tissues throughout plant development. Stress application altered the expression levels, but all three ArathNictabas showed a different expression pattern. Pseudomonas syringae infection experiments with AN4 and AN5 overexpression lines demonstrated a significantly higher tolerance of several transgenic lines to P. syringae compared to wild type plants. Finally, AN4 was shown to interact with two enzymes involved in plant defense, namely TGG1 and BGLU23. Taken together, our data suggest that the ArathNictabas represent stress-regulated proteins with a possible role in plant stress responses. On the long term this research can contribute to the development of more stress-resistant plants.

  4. Phytoplasma effector SAP54 induces indeterminate leaf-like flower development in Arabidopsis plants.

    Science.gov (United States)

    MacLean, Allyson M; Sugio, Akiko; Makarova, Olga V; Findlay, Kim C; Grieve, Victoria M; Tóth, Réka; Nicolaisen, Mogens; Hogenhout, Saskia A

    2011-10-01

    Phytoplasmas are insect-transmitted bacterial plant pathogens that cause considerable damage to a diverse range of agricultural crops globally. Symptoms induced in infected plants suggest that these phytopathogens may modulate developmental processes within the plant host. We report herein that Aster Yellows phytoplasma strain Witches' Broom (AY-WB) readily infects the model plant Arabidopsis (Arabidopsis thaliana) ecotype Columbia, inducing symptoms that are characteristic of phytoplasma infection, such as the production of green leaf-like flowers (virescence and phyllody) and increased formation of stems and branches (witches' broom). We found that the majority of genes encoding secreted AY-WB proteins (SAPs), which are candidate effector proteins, are expressed in Arabidopsis and the AY-WB insect vector Macrosteles quadrilineatus (Hemiptera; Cicadellidae). To identify which of these effector proteins induce symptoms of phyllody and virescence, we individually expressed the effector genes in Arabidopsis. From this screen, we have identified a novel AY-WB effector protein, SAP54, that alters floral development, resulting in the production of leaf-like flowers that are similar to those produced by plants infected with this phytoplasma. This study offers novel insight into the effector profile of an insect-transmitted plant pathogen and reports to our knowledge the first example of a microbial pathogen effector protein that targets flower development in a host.

  5. Arabidopsis Vacuolar Pyrophosphatase gene (AVP1) induces drought and salt tolerance in Nicotiana tabacum plants (abstract)

    International Nuclear Information System (INIS)

    Arif, A.; Mohsin, A.M.; Shafiq, S.; Zafar, Y.; Hameed, S.M.; Arif, M.; Javed, M.; Gaxiola, R.A.

    2005-01-01

    Drought and salinity are global problems. In Pakistan these problems are increasing to an alarming situation due to low rain-fall and bad agricultural practices. Salt and drought stress shows a high degree of similarity with respect to physiological, biochemical, molecular and genetic effects. This is due to the fact that sub-lethal salt-stress condition is ultimately an osmotic effect which is apparently similar to that brought in by water deficit. Genetic engineering allows the re-introduction of plant genes into their genomes by increasing their expression level. Plant vacuoles play a central role in cellular mechanisms of adaptation to salinity and drought stresses. In principle, increased vacuolar solute accumulation should have a positive impact in the adaptation of plants to salinity and drought. The active transport of the solutes depends on the proton gradients established by proton pumps. We have over expressed Arabidopsis gene AVP1 (Arabidopsis thaliana vacuolar pyro phosphatase H/sup +/ pump) to increase drought/salt tolerance in tobacco. The AVP1 ORF with a tandem repeat of 358 promoter was cloned in pPZP212 vector and Agrobacterium-mediated transformation was performed. Transgenic plants were selected on plant nutrient agar medium supplemented with 50 mg/liter kanamycin. Transgenic plants were confirmed for transfer of genes by AVP1 and nptll gene specific PCR and Southern hybridization. AVP1 transgenic plants were screened for salt tolerance by providing NaCl solution in addition to nutrient solution. AVP1 transgenic plants showed tolerance up to 300 mM NaCl as compared to control which died ten days after 200 mM NaCl. Sodium and potassium were measured in salt treated and control plants. Results showed that sodium ion uptake in the salt treated transgenic plants was four times more as compared to wild type. This remarkable increase in Na/sup +/ ion uptake indicates that AVP1 vacuole proton pumps are actively involved in the transport of Na

  6. Phytoremediation of arsenic from the contaminated soil using transgenic tobacco plants expressing ACR2 gene of Arabidopsis thaliana.

    Science.gov (United States)

    Nahar, Noor; Rahman, Aminur; Nawani, Neelu N; Ghosh, Sibdas; Mandal, Abul

    2017-11-01

    We have cloned, characterized and transformed the AtACR2 gene (arsenic reductase 2) of Arabidopsis thaliana into the genome of tobacco (Nicotiana tabacum, var Sumsun). Our results revealed that the transgenic tobacco plants are more tolerant to arsenic than the wild type ones. These plants can grow on culture medium containing 200μM arsenate, whereas the wild type can barely survive under this condition. Furthermore, when exposed to 100μM arsenate for 35days the amount of arsenic accumulated in the shoots of transgenic plants was significantly lower (28μg/g d wt.) than that found in the shoots of non-transgenic controls (40μg/g d wt.). However, the arsenic content in the roots of transgenic plants was significantly higher (2400μg/g d. wt.) than that (2100μg/g d. wt.) observed in roots of wild type plants. We have demonstrated that Arabidopsis thaliana AtACR2 gene is a potential candidate for genetic engineering of plants to develop new crop cultivars that can be grown on arsenic contaminated fields to reduce arsenic content of the soil and can become a source of food containing no arsenic or exhibiting substantially reduced amount of this metalloid. Copyright © 2017 Elsevier GmbH. All rights reserved.

  7. The maize WRKY transcription factor ZmWRKY17 negatively regulates salt stress tolerance in transgenic Arabidopsis plants.

    Science.gov (United States)

    Cai, Ronghao; Dai, Wei; Zhang, Congsheng; Wang, Yan; Wu, Min; Zhao, Yang; Ma, Qing; Xiang, Yan; Cheng, Beijiu

    2017-12-01

    We cloned and characterized the ZmWRKY17 gene from maize. Overexpression of ZmWRKY17 in Arabidopsis led to increased sensitivity to salt stress and decreased ABA sensitivity through regulating the expression of some ABA- and stress-responsive genes. The WRKY transcription factors have been reported to function as positive or negative regulators in many different biological processes including plant development, defense regulation and stress response. This study isolated a maize WRKY gene, ZmWRKY17, and characterized its role in tolerance to salt stress by generating transgenic Arabidopsis plants. Expression of the ZmWRKY17 was up-regulated by drought, salt and abscisic acid (ABA) treatments. ZmWRKY17 was localized in the nucleus with no transcriptional activation in yeast. Yeast one-hybrid assay showed that ZmWRKY17 can specifically bind to W-box, and it can activate W-box-dependent transcription in planta. Heterologous overexpression of ZmWRKY17 in Arabidopsis remarkably reduced plant tolerance to salt stress, as determined through physiological analyses of the cotyledons greening rate, root growth, relative electrical leakage and malondialdehyde content. Additionally, ZmWRKY17 transgenic plants showed decreased sensitivity to ABA during seed germination and early seedling growth. Transgenic plants accumulated higher content of ABA than wild-type (WT) plants under NaCl condition. Transcriptome and quantitative real-time PCR analyses revealed that some stress-related genes in transgenic seedlings showed lower expression level than that in the WT when treated with NaCl. Taken together, these results suggest that ZmWRKY17 may act as a negative regulator involved in the salt stress responses through ABA signalling.

  8. GDP-D-mannose epimerase regulates male gametophyte development, plant growth and leaf senescence in Arabidopsis.

    Science.gov (United States)

    Qi, Tiancong; Liu, Zhipeng; Fan, Meng; Chen, Yan; Tian, Haixia; Wu, Dewei; Gao, Hua; Ren, Chunmei; Song, Susheng; Xie, Daoxin

    2017-09-04

    Plant GDP-D-mannose epimerase (GME) converts GDP-D-mannose to GDP-L-galactose, a precursor of both L-ascorbate (vitamin C) and cell wall polysaccharides. However, the genetic functions of GME in Arabidopsis are unclear. In this study, we found that mutations in Arabidopsis GME affect pollen germination, pollen tube elongation, and transmission and development of the male gametophyte through analysis of the heterozygous GME/gme plants and the homozygous gme plants. Arabidopsis gme mutants also exhibit severe growth defects and early leaf senescence. Surprisingly, the defects in male gametophyte in the gme plants are not restored by L-ascorbate, boric acid or GDP-L-galactose, though boric acid rescues the growth defects of the mutants, indicating that GME may regulate male gametophyte development independent of L-ascorbate and GDP-L-galactose. These results reveal key roles for Arabidopsis GME in reproductive development, vegetative growth and leaf senescence, and suggest that GME regulates plant growth and controls male gametophyte development in different manners.

  9. The Use of Arabidopsis to Study Interactions between Parasitic Angiosperms and Their Plant Hosts

    Science.gov (United States)

    Goldwasser, Y.; Westwood, J. H.; Yoder, J. I.

    2002-01-01

    Parasitic plants invade host plants in order to rob them of water, minerals and nutrients. The consequences to the infected hosts can be debilitating and some of the world's most pernicious agricultural weeds are parasitic. Parasitic genera of the Scrophulariaceae and Orobanchaceae directly invade roots of neighboring plants via underground structures called haustoria. The mechanisms by which these parasites identify and associate with host plants present unsurpassed opportunities for studying chemical signaling in plant-plant interactions. Seeds of some parasites require specific host factors for efficient germination, thereby insuring the availability of an appropriate host root prior to germination. A second set of signal molecules is required to induce haustorium development and the beginning of heterotrophy. Later stages in parasitism also require the presence of host factors, although these have not yet been well characterized. Arabidopsis is being used as a model host plant to identify genetic loci associated with stimulating parasite germination, haustorium development, and parasite support. Arabidopsis is also being employed to explore how host plants respond to parasite attack. Current methodologies and recent findings in Arabidopsis – parasitic plant interactions will be discussed. PMID:22303205

  10. Arabidopsis thaliana plants lacking the ARP2/3 complex show defects in cell wall assembly and auxin distribution.

    Science.gov (United States)

    Pratap Sahi, Vaidurya; Cifrová, Petra; García-González, Judith; Kotannal Baby, Innu; Mouillé, Gregory; Gineau, Emilie; Müller, Karel; Baluška, František; Soukup, Aleš; Petrášek, Jan; Schwarzerová, Katerina

    2017-12-25

    The cytoskeleton plays an important role in the synthesis of plant cell walls. Both microtubules and actin cytoskeleton are known to be involved in the morphogenesis of plant cells through their role in cell wall building. The role of ARP2/3-nucleated actin cytoskeleton in the morphogenesis of cotyledon pavement cells has been described before. Seedlings of Arabidopsis mutants lacking a functional ARP2/3 complex display specific cell wall-associated defects. In three independent Arabidopsis mutant lines lacking subunits of the ARP2/3 complex, phenotypes associated with the loss of the complex were analysed throughout plant development. Organ size and anatomy, cell wall composition, and auxin distribution were investigated. ARP2/3-related phenotype is associated with changes in cell wall composition, and the phenotype is manifested especially in mature tissues. Cell walls of mature plants contain less cellulose and a higher amount of homogalacturonan, and display changes in cell wall lignification. Vascular bundles of mutant inflorescence stems show a changed pattern of AUX1-YFP expression. Plants lacking a functional ARP2/3 complex have decreased basipetal auxin transport. The results suggest that the ARP2/3 complex has a morphogenetic function related to cell wall synthesis and auxin transport. © The Author(s) 2017. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  11. MIPS Arabidopsis thaliana Database (MAtDB): an integrated biological knowledge resource based on the first complete plant genome

    Science.gov (United States)

    Schoof, Heiko; Zaccaria, Paolo; Gundlach, Heidrun; Lemcke, Kai; Rudd, Stephen; Kolesov, Grigory; Arnold, Roland; Mewes, H. W.; Mayer, Klaus F. X.

    2002-01-01

    Arabidopsis thaliana is the first plant for which the complete genome has been sequenced and published. Annotation of complex eukaryotic genomes requires more than the assignment of genetic elements to the sequence. Besides completing the list of genes, we need to discover their cellular roles, their regulation and their interactions in order to understand the workings of the whole plant. The MIPS Arabidopsis thaliana Database (MAtDB; http://mips.gsf.de/proj/thal/db) started out as a repository for genome sequence data in the European Scientists Sequencing Arabidopsis (ESSA) project and the Arabidopsis Genome Initiative. Our aim is to transform MAtDB into an integrated biological knowledge resource by integrating diverse data, tools, query and visualization capabilities and by creating a comprehensive resource for Arabidopsis as a reference model for other species, including crop plants. PMID:11752263

  12. Fumaric acid: an overlooked form of fixed carbon in Arabidopsis and other plant species

    International Nuclear Information System (INIS)

    Chia, D.W.; Yoder, T.J.; Reiter, W.D.; Gibson, S.I.

    2000-01-01

    Photoassimilates are used by plants for production of energy, as carbon skeletons and in transport of fixed carbon between different plant organs. Many studies have been devoted to characterizing the factors that. regulate photoassimilate concentrations in different plant species. Most studies examining photoassimilate concentrations in C(sub 3) plants have focused on analyzing starch and soluble sugars. However, work presented here demonstrates that a number of C(sub 3) plants, including the popular model organism Arabidopsis thaliana (L.) Heynh., and agriculturally important plants, such as soybean[Glycine ma (L.) Merr.], contain significant quantities of furnaric acid. In fact, furnaric acid can accumulate to levels of several mg per g fresh weight in A-abidopsis leaves, often exceeding starch and soluble sugar levels. Furnaric acid is a component of the tricarboxylic acid cycle and, like starch and soluble sugars, can be metabolized to yield energy and carbon skeletons for production of other compounds. Fumaric acid concentrations increase with plant age and light intensity in Arabidopsis leaves. Arabidopsis phloem exudates contain significant quantities of fumaric acid, raising the possibility that fumaric acid may function in carbon transport

  13. Fumaric acid: an overlooked form of fixed carbon in Arabidopsis and other plant species

    Energy Technology Data Exchange (ETDEWEB)

    Chia, D.W.; Yoder, T.J.; Reiter, W.D.; Gibson, S.I.

    2000-10-01

    Photoassimilates are used by plants for production of energy, as carbon skeletons and in transport of fixed carbon between different plant organs. Many studies have been devoted to characterizing the factors that. regulate photoassimilate concentrations in different plant species. Most studies examining photoassimilate concentrations in C{sub 3} plants have focused on analyzing starch and soluble sugars. However, work presented here demonstrates that a number of C{sub 3} plants, including the popular model organism Arabidopsis thaliana (L.) Heynh., and agriculturally important plants, such as soybean [Glycine ma (L.) Merr.], contain significant quantities of furnaric acid. In fact, furnaric acid can accumulate to levels of several mg per g fresh weight in A-abidopsis leaves, often exceeding starch and soluble sugar levels. Furnaric acid is a component of the tricarboxylic acid cycle and, like starch and soluble sugars, can be metabolized to yield energy and carbon skeletons for production of other compounds. Fumaric acid concentrations increase with plant age and light intensity in Arabidopsis leaves. Arabidopsis phloem exudates contain significant quantities of fumaric acid, raising the possibility that fumaric acid may function in carbon transport.

  14. Dragon TIS Spotter: an Arabidopsis-derived predictor of translation initiation sites in plants.

    Science.gov (United States)

    Magana-Mora, Arturo; Ashoor, Haitham; Jankovic, Boris R; Kamau, Allan; Awara, Karim; Chowdhary, Rajesh; Archer, John A C; Bajic, Vladimir B

    2013-01-01

    In higher eukaryotes, the identification of translation initiation sites (TISs) has been focused on finding these signals in cDNA or mRNA sequences. Using Arabidopsis thaliana (A.t.) information, we developed a prediction tool for signals within genomic sequences of plants that correspond to TISs. Our tool requires only genome sequence, not expressed sequences. Its sensitivity/specificity is for A.t. (90.75%/92.2%), for Vitis vinifera (66.8%/94.4%) and for Populus trichocarpa (81.6%/94.4%), which suggests that our tool can be used in annotation of different plant genomes. We provide a list of features used in our model. Further study of these features may improve our understanding of mechanisms of the translation initiation. Our tool is implemented as an artificial neural network. It is available as a web-based tool and, together with the source code, the list of features, and data used for model development, is accessible at http://cbrc.kaust.edu.sa/dts.

  15. In Vitro Morphogenesis of Arabidopsis to Search for Novel Endophytic Fungi Modulating Plant Growth.

    Directory of Open Access Journals (Sweden)

    Francesco Dovana

    Full Text Available Fungal endophytes have shown to affect plant growth and to confer stress tolerance to the host; however, effects of endophytes isolated from water plants have been poorly investigated. In this study, fungi isolated from stems (stem-E and roots (root-E of Mentha aquatica L. (water mint were identified, and their morphogenetic properties analysed on in vitro cultured Arabidopsis (L. Heynh., 14 and 21 days after inoculation (DAI. Nineteen fungi were analysed and, based on ITS analysis, 17 isolates showed to be genetically distinct. The overall effect of water mint endophytes on Arabidopsis fresh (FW and dry weight (DW was neutral and positive, respectively, and the increased DW, mainly occurring 14 DAI, was possibly related to plant defence mechanism. Only three fungi increased both FW and DW of Arabidopsis at 14 and 21 DAI, thus behaving as plant growth promoting (PGP fungi. E-treatment caused a reduction of root depth and primary root length in most cases and inhibition-to-promotion of root area and lateral root length, from 14 DAI. Only Phoma macrostoma, among the water mint PGP fungi, increased both root area and depth, 21 DAI. Root depth and area 14 DAI were shown to influence DWs, indicating that the extension of the root system, and thus nutrient uptake, was an important determinant of plant dry biomass. Reduction of Arabidopsis root depth occurred to a great extent when plants where treated with stem-E while root area decreased or increased under the effects of stem-E and root-E, respectively, pointing to an influence of the endophyte origin on root extension. M. aquatica and many other perennial hydrophytes have growing worldwide application in water pollution remediation. The present study provided a model for directed screening of endophytes able to modulate plant growth in the perspective of future field applications of these fungi.

  16. In Vitro Morphogenesis of Arabidopsis to Search for Novel Endophytic Fungi Modulating Plant Growth.

    Science.gov (United States)

    Dovana, Francesco; Mucciarelli, Marco; Mascarello, Maurizio; Fusconi, Anna

    2015-01-01

    Fungal endophytes have shown to affect plant growth and to confer stress tolerance to the host; however, effects of endophytes isolated from water plants have been poorly investigated. In this study, fungi isolated from stems (stem-E) and roots (root-E) of Mentha aquatica L. (water mint) were identified, and their morphogenetic properties analysed on in vitro cultured Arabidopsis (L.) Heynh., 14 and 21 days after inoculation (DAI). Nineteen fungi were analysed and, based on ITS analysis, 17 isolates showed to be genetically distinct. The overall effect of water mint endophytes on Arabidopsis fresh (FW) and dry weight (DW) was neutral and positive, respectively, and the increased DW, mainly occurring 14 DAI, was possibly related to plant defence mechanism. Only three fungi increased both FW and DW of Arabidopsis at 14 and 21 DAI, thus behaving as plant growth promoting (PGP) fungi. E-treatment caused a reduction of root depth and primary root length in most cases and inhibition-to-promotion of root area and lateral root length, from 14 DAI. Only Phoma macrostoma, among the water mint PGP fungi, increased both root area and depth, 21 DAI. Root depth and area 14 DAI were shown to influence DWs, indicating that the extension of the root system, and thus nutrient uptake, was an important determinant of plant dry biomass. Reduction of Arabidopsis root depth occurred to a great extent when plants where treated with stem-E while root area decreased or increased under the effects of stem-E and root-E, respectively, pointing to an influence of the endophyte origin on root extension. M. aquatica and many other perennial hydrophytes have growing worldwide application in water pollution remediation. The present study provided a model for directed screening of endophytes able to modulate plant growth in the perspective of future field applications of these fungi.

  17. The importance of Arabidopsis glutathione peroxidase 8 for protecting Arabidopsis plant and E. coli cells against oxidative stress.

    Science.gov (United States)

    Gaber, Ahmed

    2014-01-01

    Glutathione peroxidases (GPXs) are major family of the reactive oxygen species (ROS) scavenging enzymes. Recently, database analysis of the Arabidopsis genome revealed a new open-reading frame, thus increasing the total number of AtGPX gene family to eight (AtGPX1-8). The effect of plant hormones like; i. e. salicylic acid (SA), jasmonic acid (JA), abscisic acid (ABA), indoleacetic acid (IAA), and mannitol on the expression of the genes confirm that the AtGPX genes family is regulated by multiple signaling pathways. The survival rate of AtGPX8 knockout plants (KO8) was significantly decreased under heat stress compared with the wild type. Moreover, the content of malondialdehyde (MDA) and protein oxidation was significantly increased in the KO8 plant cells under heat stress. Results indicating that the deficiency of AtGPX8 accelerates the progression of oxidative stress in KO8 plants. On the other hand, the overexpression of AtGPX8 in E. coli cells enhance the growth of the recombinant enzyme on media supplemented with 0.2 mM cumene hydroperoxide, 0.3 mM H 2O 2 or 600 mM NaCl.

  18. 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.

  19. Kalanchoe blossfeldiana plants expressing the Arabidopsis etr1-1 allele show reduced ethylene sensitivity.

    Science.gov (United States)

    Sanikhani, Mohsen; Mibus, Heiko; Stummann, Bjarne M; Serek, Margrethe

    2008-04-01

    Transgenic Kalanchoe blossfeldiana Poelln. with reduced ethylene sensitivity in flowers was obtained by Agrobacterium tumefaciens-mediated transformation using the plasmid pBEO210 containing the mutant ethylene receptor gene etr1-1 from Arabidopsis thaliana under the control of the flower-specific fbp1-promoter from Petunia. Three ethylene-resistent T0 lines, 300, 324 and 331, were selected and analyzed for postharvest-performance and morphological characteristics. Line 324 was found to be infertile and only slightly less ethylene-sensitive than control-plants, but lines 300 and 331 had significantly increased ethylene-resistance and were fertile. These two lines were analyzed for copy-number of the etr1-1 gene by Southern blotting and were crossed with the ethylene-sensitive cultivar 'Celine' to create T1 progeny. Line 300 contains two T-DNA copies per nucleus, one of which is rearranged, and these are unlinked according to segregation data from the crossing to 'Celine' and PCR-analysis of progeny plants. For control plants all flowers were closed after 2 days at 2 microl l(-1 )ethylene, but for line 300 only 33% were closed after 10 days. Line 331 contains three T-DNA copies per nucleus and is more sensitive to ethylene than line 300. In the line 300 the etr1-1 gene was found by RT-PCR to be expressed in petals and stamens but not in carpels and sepals. Both lines 300 and 331, and their progeny, appear morphologically and physiologically identical to control plants except for the higher ethylene resistance. Line 300 and its progeny with only one T-DNA copy have very low ethylene sensitivity and may be useful in future breeding.

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

    KAUST Repository

    Ooi, Amanda

    2016-12-01

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

  1. Geomagnetic Field (Gmf) and Plant Evolution: Investigating the Effects of Gmf Reversal on Arabidopsis thaliana Development and Gene Expression.

    Science.gov (United States)

    Bertea, Cinzia M; Narayana, Ravishankar; Agliassa, Chiara; Rodgers, Christopher T; Maffei, Massimo E

    2015-11-30

    One of the most stimulating observations in plant evolution is a correlation between the occurrence of geomagnetic field (GMF) reversals (or excursions) and the moment of the radiation of Angiosperms. This led to the hypothesis that alterations in GMF polarity may play a role in plant evolution. Here, we describe a method to test this hypothesis by exposing Arabidopsis thaliana to artificially reversed GMF conditions. We used a three-axis magnetometer and the collected data were used to calculate the magnitude of the GMF. Three DC power supplies were connected to three Helmholtz coil pairs and were controlled by a computer to alter the GMF conditions. Plants grown in Petri plates were exposed to both normal and reversed GMF conditions. Sham exposure experiments were also performed. Exposed plants were photographed during the experiment and images were analyzed to calculate root length and leaf areas. Arabidopsis total RNA was extracted and Quantitative Real Time-PCR (qPCR) analyses were performed on gene expression of CRUCIFERIN 3 (CRU3), copper transport protein1 (COTP1), Redox Responsive Transcription Factor1 (RRTF1), Fe Superoxide Dismutase 1, (FSD1), Catalase3 (CAT3), Thylakoidal Ascorbate Peroxidase (TAPX), a cytosolic Ascorbate Peroxidase1 (APX1), and NADPH/respiratory burst oxidase protein D (RbohD). Four different reference genes were analysed to normalize the results of the qPCR. The best of the four genes was selected and the most stable gene for normalization was used. Our data show for the first time that reversing the GMF polarity using triaxial coils has significant effects on plant growth and gene expression. This supports the hypothesis that GMF reversal contributes to inducing changes in plant development that might justify a higher selective pressure, eventually leading to plant evolution.

  2. Overexpression of CaDSR6 increases tolerance to drought and salt stresses in transgenic Arabidopsis plants.

    Science.gov (United States)

    Kim, Eun Yu; Seo, Young Sam; Park, Ki Youl; Kim, Soo Jin; Kim, Woo Taek

    2014-11-15

    The partial CaDSR6 (Capsicum annuum Drought Stress Responsive 6) cDNA was previously identified as a drought-induced gene in hot pepper root tissues. However, the cellular role of CaDSR6 with regard to drought stress tolerance was unknown. In this report, full-length CaDSR6 cDNA was isolated. The deduced CaDSR6 protein was composed of 234 amino acids and contained an approximately 30 amino acid-long Asp-rich domain in its central region. This Asp-rich domain was highly conserved in all plant DSR6 homologs identified and shared a sequence identity with the N-terminal regions of yeast p23(fyp) and human hTCTP, which contain Rab protein binding sites. Transgenic Arabidopsis plants overexpressing CaDSR6 (35S:CaDSR6-sGFP) were tolerant to high salinity, as identified by more vigorous root growth and higher levels of total chlorophyll than wild type plants. CaDSR6-overexpressors were also more tolerant to drought stress compared to wild type plants. The 35S:CaDSR6-sGFP leaves retained their water content and chlorophyll more efficiently than wild type leaves in response to dehydration stress. The expression of drought-induced marker genes, such as RD20, RD22, RD26, RD29A, RD29B, RAB18, KIN2, ABF3, and ABI5, was markedly increased in CaDSR6-overexpressing plants relative to wild type plants under both normal and drought conditions. These results suggest that overexpression of CaDSR6 is associated with increased levels of stress-induced genes, which, in turn, conferred a drought tolerant phenotype in transgenic Arabidopsis plants. Overall, our data suggest that CaDSR6 plays a positive role in the response to drought and salt stresses. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Cytokinins induce transcriptional reprograming and improve Arabidopsis plant performance under drought and salt stress conditions.

    Directory of Open Access Journals (Sweden)

    Natali Shirron

    2016-10-01

    Full Text Available In nature, annual plants respond to abiotic stresses by activating a specific genetic program leading to early flowering and accelerated senescence. Although, in nature, this phenomenon supports survival under unfavorable environmental conditions, it may have negative agro-economic impacts on crop productivity. Overcoming this genetic programing by cytokinins (CK has recently been shown in transgenic plants that overproduce CK. These transgenic plants displayed a significant increase in plant productivity under drought stress conditions. We investigated the role of CK in reverting the transcriptional program that is activated under abiotic stress conditions and allowing sustainable plant growth. We employed 2 complementary approaches: Ectopic overexpression of CK, and applying exogenous CK to detached Arabidopsis leaves. Transgenic Arabidopsis plants transformed with the isopentyltransferase (IPT gene under the regulation of the senescence associated receptor kinase (SARK promoter displayed a significant drought resistance. A transcriptomic analysis using RNA sequencing was performed to explore the response mechanisms under elevated CK levels during salinity stress. This analysis showed that under such stress, CK triggered transcriptional reprograming that resulted in attenuated stress-dependent inhibition of vegetative growth and delayed premature plant senescence. Our data suggest that elevated CK levels led to stress tolerance by retaining the expression of genes associated with plant growth and metabolism whose expression typically decreases under stress conditions. In conclusion, we hypothesize that CK allows sustainable plant growth under unfavorable environmental conditions by activating gene expression related to growth processes and by preventing the expression of genes related to the activation of premature senescence.

  4. AtHD2D gene plays a role in plant growth, development and response to abiotic stresses in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Zhaofen eHan

    2016-03-01

    Full Text Available Abstracts: The histone deacetylases play important roles in the regulation of gene expression and the subsequent control of a number of important biological processes, including those involved in the response to environmental stress. A specific group of histone deacetylase genes, HD2, is present in plants. In Arabidopsis, HD2s include HD2A, HD2B, HD2C and HD2D. Previous research showed that HD2A, HD2B and HD2C are more related in terms of expression and function, but not HD2D. In this report, we studied different aspects of AtHD2D in Arabidopsis with respect to plant response to drought and other abiotic stresses. Bioinformatics analysis indicates that HD2D is distantly related to other HD2 genes. Transient expression in Nicotiana benthamiana and stable expression in Arabidopsis of AtHD2D fused with gfp showed that AtHD2D was expressed in the nucleus. Overexpression of AtHD2D resulted in developmental changes including fewer main roots, more lateral roots, and a higher root:shoot ratio. Seed germination and plant flowering time were delayed in transgenic plants expressing AtHD2D, but these plants exhibited higher degrees of tolerance to abiotic stresses, including drought, salt and cold stresses. Physiological studies indicated that the malondialdehyde (MDA content was high in wild-type plants but in plants overexpressing HD2D the MDA level increased slowly in response to stress conditions of drought, cold, and salt stress. Furthermore, electrolyte leakage in leaf cells of wild type plants increased but remained stable in transgenic plants. Our results indicate that AtHD2D is unique among HD2 genes and it plays a role in plant growth and development regulation and these changes can modulate plant stress responses.

  5. Synthesis of Hydroxylated Sterols in Transgenic Arabidopsis Plants Alters Growth and Steroid Metabolism1[C][W][OA

    Science.gov (United States)

    Beste, Lisa; Nahar, Nurun; Dalman, Kerstin; Fujioka, Shozo; Jonsson, Lisbeth; Dutta, Paresh C.; Sitbon, Folke

    2011-01-01

    To explore mechanisms in plant sterol homeostasis, we have here increased the turnover of sterols in Arabidopsis (Arabidopsis thaliana) and potato (Solanum tuberosum) plants by overexpressing four mouse cDNA encoding cholesterol hydroxylases (CHs), hydroxylating cholesterol at the C-7, C-24, C-25, or C-27 positions. Compared to the wild type, the four types of Arabidopsis transformant showed varying degrees of phenotypic alteration, the strongest one being in CH25 lines, which were dark-green dwarfs resembling brassinosteroid-related mutants. Gas chromatography-mass spectrometry analysis of extracts from wild-type Arabidopsis plants revealed trace levels of α and β forms of 7-hydroxycholesterol, 7-hydroxycampesterol, and 7-hydroxysitosterol. The expected hydroxycholesterol metabolites in CH7-, CH24-, and CH25 transformants were identified and quantified using gas chromatography-mass spectrometry. Additional hydroxysterol forms were also observed, particularly in CH25 plants. In CH24 and CH25 lines, but not in CH7 ones, the presence of hydroxysterols was correlated with a considerable alteration of the sterol profile and an increased sterol methyltransferase activity in microsomes. Moreover, CH25 lines contained clearly reduced levels of brassinosteroids, and displayed an enhanced drought tolerance. Equivalent transformations of potato plants with the CH25 construct increased hydroxysterol levels, but without the concomitant alteration of growth and sterol profiles observed in Arabidopsis. The results suggest that an increased hydroxylation of cholesterol and/or other sterols in Arabidopsis triggers compensatory processes, acting to maintain sterols at adequate levels. PMID:21746809

  6. Saccharomyces cerevisiae FKBP12 binds Arabidopsis thaliana TOR and its expression in plants leads to rapamycin susceptibility.

    Science.gov (United States)

    Sormani, Rodnay; Yao, Lei; Menand, Benoît; Ennar, Najla; Lecampion, Cécile; Meyer, Christian; Robaglia, Christophe

    2007-06-01

    The eukaryotic TOR pathway controls translation, growth and the cell cycle in response to environmental signals such as nutrients or growth-stimulating factors. The TOR protein kinase can be inactivated by the antibiotic rapamycin following the formation of a ternary complex between TOR, rapamycin and FKBP12 proteins. The TOR protein is also found in higher plants despite the fact that they are rapamycin insensitive. Previous findings using the yeast two hybrid system suggest that the FKBP12 plant homolog is unable to form a complex with rapamycin and TOR, while the FRB domain of plant TOR is still able to bind to heterologous FKBP12 in the presence of rapamycin. The resistance to rapamycin is therefore limiting the molecular dissection of the TOR pathway in higher plants. Here we show that none of the FKBPs from the model plant Arabidopsis (AtFKBPs) is able to form a ternary complex with the FRB domain of AtTOR in the presence of rapamycin in a two hybrid system. An antibody has been raised against the AtTOR protein and binding of recombinant yeast ScFKBP12 to native Arabidopsis TOR in the presence of rapamycin was demonstrated in pull-down experiments. Transgenic lines expressing ScFKBP12 were produced and were found to display a rapamycin-dependent reduction of the primary root growth and a lowered accumulation of high molecular weight polysomes. These results further strengthen the idea that plant resistance to rapamycin evolved as a consequence of mutations in plant FKBP proteins. The production of rapamycin-sensitive plants through the expression of the ScFKBP12 protein illustrates the conservation of the TOR pathway in eukaryotes. Since AtTOR null mutants were found to be embryo lethal 1, transgenic ScFKBP12 plants will provide an useful tool for the post-embryonic study of plant TOR functions. This work also establish for the first time a link between TOR activity and translation in plant cells.

  7. Saccharomyces cerevisiae FKBP12 binds Arabidopsis thaliana TOR and its expression in plants leads to rapamycin susceptibility

    Directory of Open Access Journals (Sweden)

    Meyer Christian

    2007-06-01

    Full Text Available Abstract Background The eukaryotic TOR pathway controls translation, growth and the cell cycle in response to environmental signals such as nutrients or growth-stimulating factors. The TOR protein kinase can be inactivated by the antibiotic rapamycin following the formation of a ternary complex between TOR, rapamycin and FKBP12 proteins. The TOR protein is also found in higher plants despite the fact that they are rapamycin insensitive. Previous findings using the yeast two hybrid system suggest that the FKBP12 plant homolog is unable to form a complex with rapamycin and TOR, while the FRB domain of plant TOR is still able to bind to heterologous FKBP12 in the presence of rapamycin. The resistance to rapamycin is therefore limiting the molecular dissection of the TOR pathway in higher plants. Results Here we show that none of the FKBPs from the model plant Arabidopsis (AtFKBPs is able to form a ternary complex with the FRB domain of AtTOR in the presence of rapamycin in a two hybrid system. An antibody has been raised against the AtTOR protein and binding of recombinant yeast ScFKBP12 to native Arabidopsis TOR in the presence of rapamycin was demonstrated in pull-down experiments. Transgenic lines expressing ScFKBP12 were produced and were found to display a rapamycin-dependent reduction of the primary root growth and a lowered accumulation of high molecular weight polysomes. Conclusion These results further strengthen the idea that plant resistance to rapamycin evolved as a consequence of mutations in plant FKBP proteins. The production of rapamycin-sensitive plants through the expression of the ScFKBP12 protein illustrates the conservation of the TOR pathway in eukaryotes. Since AtTOR null mutants were found to be embryo lethal 1, transgenic ScFKBP12 plants will provide an useful tool for the post-embryonic study of plant TOR functions. This work also establish for the first time a link between TOR activity and translation in plant cells

  8. Gravity response mechanisms of lateral organs and the control of plant architecture in Arabidopsis

    Science.gov (United States)

    Mullen, J.; Hangarter, R.

    Most research on gravity responses in plants has focused on primary roots and shoots, which typically grow in a vertical orientation. However, the patterns of lateral organ formation and their growth orientation, which typically are not vertical, govern plant architecture. For example, in Arabidopsis, when lateral roots emerge from the primary root, they grow at a nearly horizontal orientation. As they elongate, the roots slowly curve until they eventually reach a vertical orientation. The regulation of this lateral root orientation is an important component affecting the overall root system architecture. We have found that this change in orientation is not simply due to the onset of gravitropic competence, as non-vertical lateral roots are capable of both positive and negative gravitropism. Thus, the horizontal growth of the new lateral roots is determined by what is called the gravitropic set-point angle (GSA). In Arabidopsis shoots, rosette leaves and inflorescence branches also display GSA-dependent developmental changes in their orientation. The developmental control of the GSA of lateral organs in Arabidopsis provides us with a useful system for investigating the components involved in regulating directionality of tropistic responses. We have identified several Arabidopsis mutants that have either altered lateral root orientations, altered orientation of lateral organs in the shoot, or both, but maintain normal primary organ orientation. The mgsa ({m}odified {g}ravitropic {s}et-point {a}ngle) mutants with both altered lateral root and shoot orientation show that there are common components in the regulation of growth orientation in the different organs. Rosette leaves and lateral roots also have in common a regulation of positioning by red light. Further molecular and physiological analyses of the GSA mutants will provide insight into the basis of GSA regulation and, thus, a better understanding of how gravity controls plant architecture. [This work was

  9. The Arabidopsis synaptotagmin SYTA regulates the cell-to-cell movement of diverse plant viruses

    Directory of Open Access Journals (Sweden)

    Asako eUchiyama

    2014-11-01

    Full Text Available Synaptotagmins are a large gene family in animals that have been extensively characterized due to their role as calcium sensors to regulate synaptic vesicle exocytosis and endocytosis in neurons, and dense core vesicle exocytosis for hormone secretion from neuroendocrine cells. Thought to be exclusive to animals, synaptotagmins have recently been characterized in Arabidopsis thaliana, in which they comprise a five gene family. Using infectivity and leaf-based functional assays, we have shown that Arabidopsis SYTA regulates endocytosis and marks an endosomal vesicle recycling pathway to regulate movement protein-mediated trafficking of the Begomovirus Cabbage leaf curl virus (CaLCuV and the Tobamovirus Tobacco mosaic virus (TMV through plasmodesmata (Lewis and Lazarowitz, 2010. To determine whether SYTA has a central role in regulating the cell-to-cell trafficking of a wider range of diverse plant viruses, we extended our studies here to examine the role of SYTA in the cell-to-cell movement of additional plant viruses that employ different modes of movement, namely the Potyvirus Turnip mosaic virus (TuMV, the Caulimovirus Cauliflower mosaic virus (CaMV and the Tobamovirus Turnip vein clearing virus (TVCV, which in contrast to TMV does efficiently infect Arabidopsis. We found that both TuMV and TVCV systemic infection, and the cell-to-cell trafficking of the their movement proteins, were delayed in the Arabidopsis Col-0 syta-1 knockdown mutant. In contrast, CaMV systemic infection was not inhibited in syta-1. Our studies show that SYTA is a key regulator of plant virus intercellular movement, being necessary for the ability of diverse cell-to-cell movement proteins encoded by Begomoviruses (CaLCuV MP, Tobamoviruses (TVCV and TMV 30K protein and Potyviruses (TuMV P3N-PIPO to alter PD and thereby mediate virus cell-to-cell spread.

  10. ARIGAN: Synthetic Arabidopsis Plants using Generative Adversarial Network

    OpenAIRE

    Giuffrida, Mario Valerio; Scharr, Hanno; Tsaftaris, Sotirios A

    2017-01-01

    In recent years, there has been an increasing interest in image-based plant phenotyping, applying state-of-the-art machine learning approaches to tackle challenging problems, such as leaf segmentation (a multi-instance problem) and counting. Most of these algorithms need labelled data to learn a model for the task at hand. Despite the recent release of a few plant phenotyping datasets, large annotated plant image datasets for the purpose of training deep learning algorithms are lacking. One c...

  11. Cytoplasniic differentiation during microsporogenesis in higher plants

    Directory of Open Access Journals (Sweden)

    H. Dichinnson

    2014-01-01

    Full Text Available Conspicuous cytoplasmic dedifferentiation in the pollen mother cells takes place early in the meiotic prophase of many plants. This event involves the removal of much of the cytoplasmic RNA. and the differentiation of both plastids and mitochondria to approaching the sole expression of their genomes. Much of the RNA removed from the cytoplasm passes to the nucleoplasm where it is utilised in the construction of a new `generation' of ribusomes. These new ribosomes are incorporated into cytoplasmic `nuclewhich disintegrate in the post-meiotic cytoplasm, restoring its ribosomes to pre-prophase levels. These changes are interpreted as evidence of a process by which the cytoplasm is cleansed of sporophytic control elements, both for the expression of the new gametophytic genome, and in the female cells of higher plants, for transmission to the new generation. The absence of control elements (presumably long-term messenger RNA from the cytoplasm would result in the dedifferentiation observed in the organelles, and the low levels of reserves in these cells presumably results in characteristically lengthy and unusual redifferentiation of both plastids and mitochondria, once information-carrying molecules again enter the cytosol.

  12. Mechanisms of male sterility in higher plants

    Energy Technology Data Exchange (ETDEWEB)

    Ohta, Yasuo [Tsukuba Univ., Sakura, Ibaraki (Japan)

    1982-03-01

    The mechanisms causing male sterility in higher plants were classified into two major categories: genetic and non-genetic. The former was further divided into six classes: 1) Anomality in spindle mechanism during meiosis, 2) chromosomal anomality such as haploidy, polyploidy, aneuploidy, chromosome some deficiency, inversion and reciprocal translocation, 3) presence of male sterile genes, 4) cytoplasmic abnormality, 5) the combination of some specific cytoplasm with particular genes, and 6) infections of microorganisms or viruses. Each mechanism was briefly explained, and the methods for the maintenance of parent lines for heterosis breeding and hybrid seed production were described. The non-genetic male sterility was classified into four types, which are caused by 1) low or high temperature, 2) water deficiency, 3) application of chemicals, and 4) radiation, with a brief explanation given for each of them.

  13. Mechanisms of male sterility in higher plants

    International Nuclear Information System (INIS)

    Ohta, Yasuo

    1982-01-01

    The mechanisms causing male sterility in higher plants were classified into two major categories: genetic and non-genetic. The former was further divided into six classes: 1) Anomality in spindle mechanism during meiosis, 2) chromosomal anomality such as haploidy, polyploidy, aneuploidy, chromosome some deficiency, inversion and reciprocal translocation, 3) presence of male sterile genes, 4) cytoplasmic abnormality, 5) the combination of some specific cytoplasm with particular genes, and 6) infections of microorganisms or viruses. Each mechanism was briefly explained, and the methods for the maintenance of parent lines for heterosis breeding and hybrid seed production were described. The non-genetic male sterility was classified into four types, which are caused by 1) low or high temperature, 2) water deficiency, 3) application of chemicals, and 4) radiation, with a brief explanation given for each of them. (Kaihara, S.)

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

    DEFF Research Database (Denmark)

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

    2001-01-01

    Classic FYVE zinc-finger domains recognize the phosphoinositide signal PtdIns3P and share the basic (R/K)(1)(R/K)HHCR(6) (single-letter amino acid codes) consensus sequence. This domain is present in predicted PtdIns3P 5-kinases and lipases from Arabidopsis thaliana. Other Arabidopsis proteins......) of the basic motif. Dot-blot and liposome-binding assays were used in vitro to examine the phospholipid-binding ability of isolated PRAF domains. Whereas the PH domain preferentially bound PtdIns(4,5)P(2), the variant FYVE domain showed a weaker charge-dependent binding of phosphoinositides. In contrast....... A biochemical function for PRAF was indicated by its ability to catalyse guanine nucleotide exchange on some of the small GTPases of the Rab family, permitting a discussion of the biological roles of plant FYVE proteins and their regulation by phosphoinositides....

  15. An improved, low-cost, hydroponic system for growing Arabidopsis and other plant species under aseptic conditions.

    Science.gov (United States)

    Alatorre-Cobos, Fulgencio; Calderón-Vázquez, Carlos; Ibarra-Laclette, Enrique; Yong-Villalobos, Lenin; Pérez-Torres, Claudia-Anahí; Oropeza-Aburto, Araceli; Méndez-Bravo, Alfonso; González-Morales, Sandra-Isabel; Gutiérrez-Alanís, Dolores; Chacón-López, Alejandra; Peña-Ocaña, Betsy-Anaid; Herrera-Estrella, Luis

    2014-03-21

    Hydroponics is a plant growth system that provides a more precise control of growth media composition. Several hydroponic systems have been reported for Arabidopsis and other model plants. The ease of system set up, cost of the growth system and flexibility to characterize and harvest plant material are features continually improved in new hydroponic system reported. We developed a hydroponic culture system for Arabidopsis and other model plants. This low cost, proficient, and novel system is based on recyclable and sterilizable plastic containers, which are readily available from local suppliers. Our system allows a large-scale manipulation of seedlings. It adapts to different growing treatments and has an extended growth window until adult plants are established. The novel seed-holder also facilitates the transfer and harvest of seedlings. Here we report the use of our hydroponic system to analyze transcriptomic responses of Arabidopsis to nutriment availability and plant/pathogen interactions. The efficiency and functionality of our proposed hydroponic system is demonstrated in nutrient deficiency and pathogenesis experiments. Hydroponically grown Arabidopsis seedlings under long-time inorganic phosphate (Pi) deficiency showed typical changes in root architecture and high expression of marker genes involved in signaling and Pi recycling. Genome-wide transcriptional analysis of gene expression of Arabidopsis roots depleted of Pi by short time periods indicates that genes related to general stress are up-regulated before those specific to Pi signaling and metabolism. Our hydroponic system also proved useful for conducting pathogenesis essays, revealing early transcriptional activation of pathogenesis-related genes.

  16. Chrysanthemum WRKY gene CmWRKY17 negatively regulates salt stress tolerance in transgenic chrysanthemum and Arabidopsis plants.

    Science.gov (United States)

    Li, Peiling; Song, Aiping; Gao, Chunyan; Wang, Linxiao; Wang, Yinjie; Sun, Jing; Jiang, Jiafu; Chen, Fadi; Chen, Sumei

    2015-08-01

    CmWRKY17 was induced by salinity in chrysanthemum, and it might negatively regulate salt stress in transgenic plants as a transcriptional repressor. WRKY transcription factors play roles as positive or negative regulators in response to various stresses in plants. In this study, CmWRKY17 was isolated from chrysanthemum (Chrysanthemum morifolium). The gene encodes a 227-amino acid protein and belongs to the group II WRKY family, but has an atypical WRKY domain with the sequence WKKYGEK. Our data indicated that CmWRKY17 was localized to the nucleus in onion epidermal cells. CmWRKY17 showed no transcriptional activation in yeast; furthermore, luminescence assay clearly suggested that CmWRKY17 functions as a transcriptional repressor. DNA-binding assay showed that CmWRKY17 can bind to W-box. The expression of CmWRKY17 was induced by salinity in chrysanthemum, and a higher expression level was observed in the stem and leaf compared with that in the root, disk florets, and ray florets. Overexpression of CmWRKY17 in chrysanthemum and Arabidopsis increased the sensitivity to salinity stress. The activities of superoxide dismutase and peroxidase and proline content in the leaf were significantly lower in transgenic chrysanthemum than those in the wild type under salinity stress, whereas electrical conductivity was increased in transgenic plants. Expression of the stress-related genes AtRD29, AtDREB2B, AtSOS1, AtSOS2, AtSOS3, and AtNHX1 was reduced in the CmWRKY17 transgenic Arabidopsis compared with that in the wild-type Col-0. Collectively, these data suggest that CmWRKY17 may increase the salinity sensitivity in plants as a transcriptional repressor.

  17. Arabidopsis seedling flood-inoculation technique: a rapid and reliable assay for studying plant-bacterial interactions

    Directory of Open Access Journals (Sweden)

    Uppalapati Srinivasa R

    2011-10-01

    Full Text Available Abstract Background The Arabidopsis thaliana-Pseudomonas syringae model pathosystem is one of the most widely used systems to understand the mechanisms of microbial pathogenesis and plant innate immunity. Several inoculation methods have been used to study plant-pathogen interactions in this model system. However, none of the methods reported to date are similar to those occurring in nature and amicable to large-scale mutant screens. Results In this study, we developed a rapid and reliable seedling flood-inoculation method based on young Arabidopsis seedlings grown on MS medium. This method has several advantages over conventional soil-grown plant inoculation assays, including a shorter growth and incubation period, ease of inoculation and handling, uniform infection and disease development, requires less growth chamber space and is suitable for high-throughput screens. In this study we demonstrated the efficacy of the Arabidopsis seedling assay to study 1 the virulence factors of P. syringae pv. tomato DC3000, including type III protein secretion system (TTSS and phytotoxin coronatine (COR; 2 the effector-triggered immunity; and 3 Arabidopsis mutants affected in salicylic acid (SA- and pathogen-associated molecular pattern (PAMPs-mediated pathways. Furthermore, we applied this technique to study nonhost resistance (NHR responses in Arabidopsis using nonhost pathogens, such as P. syringae pv. tabaci, pv. glycinea and pv. tomato T1, and confirmed the functional role of FLAGELLIN-SENSING 2 (FLS2 in NHR. Conclusions The Arabidopsis seedling flood-inoculation assay provides a rapid, efficient and economical method for studying Arabidopsis-Pseudomonas interactions with minimal growth chamber space and time. This assay could also provide an excellent system for investigating the virulence mechanisms of P. syringae. Using this method, we demonstrated that FLS2 plays a critical role in conferring NHR against nonhost pathovars of P. syringae, but not to

  18. Rhizosphere Microbial Community Composition Affects Cadmium and Zinc Uptake by the Metal-Hyperaccumulating Plant Arabidopsis halleri

    Science.gov (United States)

    Muehe, E. Marie; Weigold, Pascal; Adaktylou, Irini J.; Planer-Friedrich, Britta; Kraemer, Ute; Kappler, Andreas

    2015-01-01

    The remediation of metal-contaminated soils by phytoextraction depends on plant growth and plant metal accessibility. Soil microorganisms can affect the accumulation of metals by plants either by directly or indirectly stimulating plant growth and activity or by (im)mobilizing and/or complexing metals. Understanding the intricate interplay of metal-accumulating plants with their rhizosphere microbiome is an important step toward the application and optimization of phytoremediation. We compared the effects of a “native” and a strongly disturbed (gamma-irradiated) soil microbial communities on cadmium and zinc accumulation by the plant Arabidopsis halleri in soil microcosm experiments. A. halleri accumulated 100% more cadmium and 15% more zinc when grown on the untreated than on the gamma-irradiated soil. Gamma irradiation affected neither plant growth nor the 1 M HCl-extractable metal content of the soil. However, it strongly altered the soil microbial community composition and overall cell numbers. Pyrosequencing of 16S rRNA gene amplicons of DNA extracted from rhizosphere samples of A. halleri identified microbial taxa (Lysobacter, Streptomyces, Agromyces, Nitrospira, “Candidatus Chloracidobacterium”) of higher relative sequence abundance in the rhizospheres of A. halleri plants grown on untreated than on gamma-irradiated soil, leading to hypotheses on their potential effect on plant metal uptake. However, further experimental evidence is required, and wherefore we discuss different mechanisms of interaction of A. halleri with its rhizosphere microbiome that might have directly or indirectly affected plant metal accumulation. Deciphering the complex interactions between A. halleri and individual microbial taxa will help to further develop soil metal phytoextraction as an efficient and sustainable remediation strategy. PMID:25595759

  19. Investigating uptake of water-dispersible CdSe/ZnS quantum dot nanoparticles by Arabidopsis thaliana plants

    International Nuclear Information System (INIS)

    Navarro, Divina A.; Bisson, Mary A.; Aga, Diana S.

    2012-01-01

    Graphical abstract: This study highlights the importance of quantum dot (QD) structural stability in preventing phytotoxicity. Overall, there is no evidence that Arabidopsis thaliana plants can internalize intact QDs within 1–7 days of exposure, with or without humic acids. Highlights: ► Potential uptake of water-dispersible CdSe/ZnS QDs by Arabidopsis was demonstrated. ► QDs were not internalized by Arabidopsis as intact particles. ► Plants exposed to Cd-, Se-, and QD + HA suspensions experienced oxidative stress. ► An effective LC–MS method proves detection of low levels of glutathione in plants. ► Uptake of Cd and/or Se leached from QDs is of major concern. - Abstract: Interest on the environmental impacts of engineered nanomaterials has rapidly increased over the past years because it is expected that these materials will eventually be released into the environment. The present work investigates the potential root uptake of water-dispersible CdSe/ZnS quantum dots (QDs) by the model plant species, Arabidopsis thaliana. Experiments revealed that Arabidopsis exposed to QDs that are dispersed in Hoagland's solution for 1–7 days did not internalize intact QDs. Analysis of Cd and Se concentrations in roots and leaves by inductively-coupled plasma mass spectrometry indicated that Cd and Se from QD-treated plants were not translocated into the leaves, and remained in the root system of Arabidopsis. Furthermore, fluorescence microscopy showed strong evidence that the QDs were generally on the outside surfaces of the roots, where the amount of QDs adsorbed is dependent on the stability of the QDs in suspension. Despite no evidence of nanoparticle internalization, the ratio of reduced glutathione levels (GSH) relative to the oxidized glutathione (GSSG) in plants decreased when plants were exposed to QD dispersions containing humic acids, suggesting that QDs caused oxidative stress on the plant at this condition.

  20. Stress Response to High Magnetic Fields in Transgenic Arabidopsis thaliana Plants.

    Science.gov (United States)

    Morgan, A. N.; Watson, B. C.; Maloney, J. R.; Meisel, M. W.; Brooks, J. S.; Paul, A.-L.; Ferl, R. J.

    2000-03-01

    With increasingly greater strength magnetic fields becoming available in research and medicine, the response of living tissue exposed to high magnetic fields has come under investigation. In this experiment, genetically engineered arabidopsis plants were exposed to homogeneous magnetic fields of varying strengths using a superconducting NMR magnet (0 to 9 T) at UF and a resistive magnet (0 to 25 T) at the NHMFL. The engineered plants produce the enzyme β-glucaronidase (GUS) when under stressful environmental conditions. The level of GUS activity is determined through qualitative histochemical assays and quantitative fluorometric assays. The control group of plants experienced baseline levels of GUS activity, but some of the plants that were exposed to magnetic fields in excess of 9 T show increased stress response. Additional information is available at http://www.phys.ufl.edu/ ~meisel/maglev.htm.

  1. Arabidopsis thaliana: A model host plant to study plant-pathogen interaction using rice false smut isolates of Ustilaginoidea virens

    Directory of Open Access Journals (Sweden)

    Mebeaselassie eAndargie

    2016-02-01

    Full Text Available Rice false smut fungus which is a biotrophic fungal pathogen causes an important rice disease and bring a severe damage where rice is cultivated. We established a new fungal-plant pathosystem where Ustilaginoidea virens was able to interact compatibly with the model plant Arabidopsis thaliana. Disease symptoms were apparent on the leaves of the plants after 6 days of post inoculation in the form of chlorosis. Cytological studies showed that U. virens caused a heavy infestation inside the cells of the chlorotic tissues. Development and colonization of aerial mycelia in association with floral organ, particularly on anther and stigma of the flowers after 3 weeks of post inoculation was evident which finally caused infection on the developing seeds and pod tissues. The fungus adopts a uniquely biotrophic infection strategy in roots and spreads without causing a loss of host cell viability. We have also demonstrated that U. virens isolates infect Arabidopsis and the plant subsequently activates different defense response mechanisms which are witnessed by the expression of pathogenesis-related genes, PR-1, PR-2, PR-5, PDF1.1 and PDF1.2. The established A. thaliana–U. virens pathosystem will now permit various follow-up molecular genetics and gene expression experiments to be performed to identify the defense signals and responses that restrict fungal hyphae colonization in planta and also provide initial evidence for tissue-adapted fungal infection strategies.

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

    Science.gov (United States)

    Abu Bakar, Fauziah; Yeo, Chew Chieng; Harikrishna, Jennifer Ann

    2016-01-01

    Bacterial toxin-antitoxin (TA) systems have various cellular functions, including as part of the general stress response. The genome of the Gram-positive human pathogen Streptococcus pneumoniae harbors several putative TA systems, including yefM-yoeBSpn, which is one of four systems that had been demonstrated to be biologically functional. Overexpression of the yoeBSpn toxin gene resulted in cell stasis and eventually cell death in its native host, as well as in Escherichia coli. Our previous work showed that induced expression of a yoeBSpn toxin-Green Fluorescent Protein (GFP) fusion gene apparently triggered apoptosis and was lethal in the model plant, Arabidopsis thaliana. In this study, we investigated the effects of co-expression of the yefMSpn antitoxin and yoeBSpn toxin-GFP fusion in transgenic A. thaliana. When co-expressed in Arabidopsis, the YefMSpn antitoxin was found to neutralize the toxicity of YoeBSpn-GFP. Interestingly, the inducible expression of both yefMSpn antitoxin and yoeBSpn toxin-GFP fusion in transgenic hybrid Arabidopsis resulted in larger rosette leaves and taller plants with a higher number of inflorescence stems and increased silique production. To our knowledge, this is the first demonstration of a prokaryotic antitoxin neutralizing its cognate toxin in plant cells. PMID:27104531

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

    Directory of Open Access Journals (Sweden)

    Fauziah Abu Bakar

    2016-04-01

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

  4. Membrane-localized extra-large G proteins and Gbg of the heterotrimeric G proteins form functional complexes engaged in plant immunity in Arabidopsis.

    Science.gov (United States)

    Maruta, Natsumi; Trusov, Yuri; Brenya, Eric; Parekh, Urvi; Botella, José Ramón

    2015-03-01

    In animals, heterotrimeric G proteins, comprising Ga, Gb, and Gg subunits, are molecular switches whose function tightly depends on Ga and Gbg interaction. Intriguingly, in Arabidopsis (Arabidopsis thaliana), multiple defense responses involve Gbg, but not Ga. We report here that the Gbg dimer directly partners with extra-large G proteins (XLGs) to mediate plant immunity. Arabidopsis mutants deficient in XLGs, Gb, and Gg are similarly compromised in several pathogen defense responses, including disease development and production of reactive oxygen species. Genetic analysis of double, triple, and quadruple mutants confirmed that XLGs and Gbg functionally interact in the same defense signaling pathways. In addition, mutations in XLG2 suppressed the seedling lethal and cell death phenotypes of BRASSINOSTEROID INSENSITIVE1-associated receptor kinase1-interacting receptor-like kinase1 mutants in an identical way as reported for Arabidopsis Gb-deficient mutants. Yeast (Saccharomyces cerevisiae) three-hybrid and bimolecular fluorescent complementation assays revealed that XLG2 physically interacts with all three possible Gbg dimers at the plasma membrane. Phylogenetic analysis indicated a close relationship between XLGs and plant Ga subunits, placing the divergence point at the dawn of land plant evolution. Based on these findings, we conclude that XLGs form functional complexes with Gbg dimers, although the mechanism of action of these complexes, including activation/deactivation, must be radically different form the one used by the canonical Ga subunit and are not likely to share the same receptors. Accordingly, XLGs expand the repertoire of heterotrimeric G proteins in plants and reveal a higher level of diversity in heterotrimeric G protein signaling.

  5. Identification, duplication, evolution and expression analyses of caleosins in Brassica plants and Arabidopsis subspecies.

    Science.gov (United States)

    Shen, Yue; Liu, Mingzhe; Wang, Lili; Li, Zhuowei; Taylor, David C; Li, Zhixi; Zhang, Meng

    2016-04-01

    Caleosins are a class of Ca(2+) binding proteins that appear to be ubiquitous in plants. Some of the main proteins embedded in the lipid monolayer of lipid droplets, caleosins, play critical roles in the degradation of storage lipids during germination and in lipid trafficking. Some of them have been shown to have histidine-dependent peroxygenase activity, which is believed to participate in stress responses in Arabidopsis. In the model plant Arabidopsis thaliana, caleosins have been examined extensively. However, little is known on a genome-wide scale about these proteins in other members of the Brassicaceae. In this study, 51 caleosins in Brassica plants and Arabidopsis lyrata were investigated and analyzed in silico. Among them, 31 caleosins, including 7 in A. lyrata, 11 in Brassica oleracea and 13 in Brassica napus, are herein identified for the first time. Segmental duplication was the main form of gene expansion. Alignment, motif and phylogenetic analyses showed that Brassica caleosins belong to either the H-family or the L-family with different motif structures and physicochemical properties. Our findings strongly suggest that L-caleosins are evolved from H-caleosins. Predicted phosphorylation sites were differentially conserved in H-caleosin and L-caleosins, respectively. 'RY-repeat' elements and phytohormone-related cis-elements were identified in different caleosins, which suggest diverse physiological functions. Gene structure analysis indicated that most caleosins (38 out of 44) contained six exons and five introns and their intron phases were highly conserved. Structurally integrated caleosins, such as BrCLO3-3 and BrCLO4-2, showed high expression levels and may have important roles. Some caleosins, such as BrCLO2 and BoCLO8-2, lost motifs of the calcium binding domain, proline knot, potential phosphorylation sites and haem-binding sites. Combined with their low expression, it is suggested that these caleosins may have lost function.

  6. Plant responses to environmental stress: regulation and functions of the Arabidopsis TCH genes

    Science.gov (United States)

    Braam, J.; Sistrunk, M. L.; Polisensky, D. H.; Xu, W.; Purugganan, M. M.; Antosiewicz, D. M.; Campbell, P.; Johnson, K. A.; McIntire, L. V. (Principal Investigator)

    1997-01-01

    Expression of the Arabidopsis TCH genes is markedly upregulated in response to a variety of environmental stimuli including the seemingly innocuous stimulus of touch. Understanding the mechanism(s) and factors that control TCH gene regulation will shed light on the signaling pathways that enable plants to respond to environmental conditions. The TCH proteins include calmodulin, calmodulin-related proteins and a xyloglucan endotransglycosylase. Expression analyses and localization of protein accumulation indicates that the potential sites of TCH protein function include expanding cells and tissues under mechanical strain. We hypothesize that at least a subset of the TCH proteins may collaborate in cell wall biogenesis.

  7. Chronical influence of radiation and lead on mutation rates in plants of Arabidopsis Thaliana (L.) Heynh

    International Nuclear Information System (INIS)

    Kryukov, V.I.; Shishkin, V.A.; Sokolenko, S.F.

    1996-01-01

    Plants of Arabidopsis thaliana were grown in a laboratory conditions on the soil (black earth, chernozem) which was polluted with a radioactive isotopes of cesium, 134+137 Cs. Increase in specific activity of samples from 217 to 1025 and 2529 Bq/kg resulted in increase of embryonic mutation rate in Arabidopsis from 8.2 to 20.2 and 51.6 % respectively. Bringing Pb 2+ in a dose of 16 mg into the soil resulted in statistically significant decrease in mutation rate. Further increase of lead concentration in radioactive soils to 32, 64, 96, 160 and 320 mg/kg resulted in growth of the mutation rates in the plants which were grown on the soil with low and middle specific activity of cesium, and in decrease of the mutation rates in the plants which were grown on the soil with high specific radioactivity. The last process apparently was connected with the intensive growth in the number of sterile seeds in the pods. 19 refs.; 2 figs.; 4 tabs

  8. Genome-wide analysis of protein disorder in Arabidopsis thaliana: implications for plant environmental adaptation.

    Science.gov (United States)

    Pietrosemoli, Natalia; García-Martín, Juan A; Solano, Roberto; Pazos, Florencio

    2013-01-01

    Intrinsically disordered proteins/regions (IDPs/IDRs) are currently recognized as a widespread phenomenon having key cellular functions. Still, many aspects of the function of these proteins need to be unveiled. IDPs conformational flexibility allows them to recognize and interact with multiple partners, and confers them larger interaction surfaces that may increase interaction speed. For this reason, molecular interactions mediated by IDPs/IDRs are particularly abundant in certain types of protein interactions, such as those of signaling and cell cycle control. We present the first large-scale study of IDPs in Arabidopsis thaliana, the most widely used model organism in plant biology, in order to get insight into the biological roles of these proteins in plants. The work includes a comparative analysis with the human proteome to highlight the differential use of disorder in both species. Results show that while human proteins are in general more disordered, certain functional classes, mainly related to environmental response, are significantly more enriched in disorder in Arabidopsis. We propose that because plants cannot escape from environmental conditions as animals do, they use disorder as a simple and fast mechanism, independent of transcriptional control, for introducing versatility in the interaction networks underlying these biological processes so that they can quickly adapt and respond to challenging environmental conditions.

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

    Science.gov (United States)

    Somerville, Chris R [Portola Valley, CA; Scheible, Wolf [Golm, DE

    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.

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

    KAUST Repository

    Turek, Ilona; Wheeler, Janet I.; Gehring, Christoph A; Irving, Helen R.; Marondedze, Claudius

    2015-01-01

    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.

  11. 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.

  12. The mitochondrial phosphate transporters modulate plant responses to salt stress via affecting ATP and gibberellin metabolism in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Wei Zhu

    Full Text Available The mitochondrial phosphate transporter (MPT plays crucial roles in ATP production in plant cells. Three MPT genes have been identified in Arabidopsis thaliana. Here we report that the mRNA accumulations of AtMPTs were up-regulated by high salinity stress in A. thaliana seedlings. And the transgenic lines overexpressing AtMPTs displayed increased sensitivity to salt stress compared with the wild-type plants during seed germination and seedling establishment stages. ATP content and energy charge was higher in overexpressing plants than those in wild-type A. thaliana under salt stress. Accordingly, the salt-sensitive phenotype of overexpressing plants was recovered after the exogenous application of atractyloside due to the change of ATP content. Interestingly, Genevestigator survey and qRT-PCR analysis indicated a large number of genes, including those related to gibberellin synthesis could be regulated by the energy availability change under stress conditions in A. thaliana. Moreover, the exogenous application of uniconazole to overexpressing lines showed that gibberellin homeostasis was disturbed in the overexpressors. Our studies reveal a possible link between the ATP content mediated by AtMPTs and gibberellin metabolism in responses to high salinity stress in A. thaliana.

  13. Overexpression of ARGOS Genes Modifies Plant Sensitivity to Ethylene, Leading to Improved Drought Tolerance in Both Arabidopsis and Maize.

    Science.gov (United States)

    Shi, Jinrui; Habben, Jeffrey E; Archibald, Rayeann L; Drummond, Bruce J; Chamberlin, Mark A; Williams, Robert W; Lafitte, H Renee; Weers, Ben P

    2015-09-01

    Lack of sufficient water is a major limiting factor to crop production worldwide, and the development of drought-tolerant germplasm is needed to improve crop productivity. The phytohormone ethylene modulates plant growth and development as well as plant response to abiotic stress. Recent research has shown that modifying ethylene biosynthesis and signaling can enhance plant drought tolerance. Here, we report novel negative regulators of ethylene signal transduction in Arabidopsis (Arabidopsis thaliana) and maize (Zea mays). These regulators are encoded by the ARGOS gene family. In Arabidopsis, overexpression of maize ARGOS1 (ZmARGOS1), ZmARGOS8, Arabidopsis ARGOS homolog ORGAN SIZE RELATED1 (AtOSR1), and AtOSR2 reduced plant sensitivity to ethylene, leading to enhanced drought tolerance. RNA profiling and genetic analysis suggested that the ZmARGOS1 transgene acts between an ethylene receptor and CONSTITUTIVE TRIPLE RESPONSE1 in the ethylene signaling pathway, affecting ethylene perception or the early stages of ethylene signaling. Overexpressed ZmARGOS1 is localized to the endoplasmic reticulum and Golgi membrane, where the ethylene receptors and the ethylene signaling protein ETHYLENE-INSENSITIVE2 and REVERSION-TO-ETHYLENE SENSITIVITY1 reside. In transgenic maize plants, overexpression of ARGOS genes also reduces ethylene sensitivity. Moreover, field testing showed that UBIQUITIN1:ZmARGOS8 maize events had a greater grain yield than nontransgenic controls under both drought stress and well-watered conditions. © 2015 American Society of Plant Biologists. All Rights Reserved.

  14. Phytoplasma Effector SAP54 Induces Indeterminate Leaf-Like Flower Development in Arabidopsis Plants1[C][W][OA

    Science.gov (United States)

    MacLean, Allyson M.; Sugio, Akiko; Makarova, Olga V.; Findlay, Kim C.; Grieve, Victoria M.; Tóth, Réka; Nicolaisen, Mogens; Hogenhout, Saskia A.

    2011-01-01

    Phytoplasmas are insect-transmitted bacterial plant pathogens that cause considerable damage to a diverse range of agricultural crops globally. Symptoms induced in infected plants suggest that these phytopathogens may modulate developmental processes within the plant host. We report herein that Aster Yellows phytoplasma strain Witches’ Broom (AY-WB) readily infects the model plant Arabidopsis (Arabidopsis thaliana) ecotype Columbia, inducing symptoms that are characteristic of phytoplasma infection, such as the production of green leaf-like flowers (virescence and phyllody) and increased formation of stems and branches (witches’ broom). We found that the majority of genes encoding secreted AY-WB proteins (SAPs), which are candidate effector proteins, are expressed in Arabidopsis and the AY-WB insect vector Macrosteles quadrilineatus (Hemiptera; Cicadellidae). To identify which of these effector proteins induce symptoms of phyllody and virescence, we individually expressed the effector genes in Arabidopsis. From this screen, we have identified a novel AY-WB effector protein, SAP54, that alters floral development, resulting in the production of leaf-like flowers that are similar to those produced by plants infected with this phytoplasma. This study offers novel insight into the effector profile of an insect-transmitted plant pathogen and reports to our knowledge the first example of a microbial pathogen effector protein that targets flower development in a host. PMID:21849514

  15. The cytoskeleton and gravitropism in higher plants

    Science.gov (United States)

    Blancaflor, Elison B.

    2002-01-01

    The cellular and molecular mechanisms underlying the gravitropic response of plants have continued to elude plant biologists despite more than a century of research. Lately there has been increased attention on the role of the cytoskeleton in plant gravitropism, but several controversies and major gaps in our understanding of cytoskeletal involvement in gravitropism remain. A major question in the study of plant gravitropism is how the cytoskeleton mediates early sensing and signal transduction events in plants. Much has been made of the actin cytoskeleton as the cellular structure that sedimenting amyloplasts impinge upon to trigger the downstream signaling events leading to the bending response. There is also strong molecular and biochemical evidence that the transport of auxin, an important player in gravitropism, is regulated by actin. Organizational changes in microtubules during the growth response phase of gravitropism have also been well documented, but the significance of such reorientations in controlling differential cellular growth is unclear. Studies employing pharmacological approaches to dissect cytoskeletal involvement in gravitropism have led to conflicting results and therefore need to be interpreted with caution. Despite the current controversies, the revolutionary advances in molecular, biochemical, and cell biological techniques have opened up several possibilities for further research into this difficult area. The myriad proteins associated with the plant cytoskeleton that are being rapidly characterized provide a rich assortment of candidate regulators that could be targets of the gravity signal transduction chain. Cytoskeletal and ion imaging in real time combined with mutant analysis promises to provide a fresh start into this controversial area of research.

  16. Over-expression of Arabidopsis thaliana SFD1/GLY1, the gene encoding plastid localized glycerol-3-phosphate dehydrogenase, increases plastidic lipid content in transgenic rice plants.

    Science.gov (United States)

    Singh, Vijayata; Singh, Praveen Kumar; Siddiqui, Adnan; Singh, Subaran; Banday, Zeeshan Zahoor; Nandi, Ashis Kumar

    2016-03-01

    Lipids are the major constituents of all membranous structures in plants. Plants possess two pathways for lipid biosynthesis: the prokaryotic pathway (i.e., plastidic pathway) and the eukaryotic pathway (i.e., endoplasmic-reticulum (ER) pathway). Whereas some plants synthesize galactolipids from diacylglycerol assembled in the plastid, others, including rice, derive their galactolipids from diacylglycerols assembled by the eukaryotic pathway. Arabidopsis thaliana glycerol-3-phosphate dehydrogenase (G3pDH), coded by SUPPRESSOR OF FATTY ACID DESATURASE 1 (SFD1; alias GLY1) gene, catalyzes the formation of glycerol 3-phosphate (G3p), the backbone of many membrane lipids. Here SFD1 was introduced to rice as a transgene. Arabidopsis SFD1 localizes in rice plastids and its over-expression increases plastidic membrane lipid content in transgenic rice plants without any major impact on ER lipids. The results suggest that over-expression of plastidic G3pDH enhances biosynthesis of plastid-localized lipids in rice. Lipid composition in the transgenic plants is consistent with increased phosphatidylglycerol synthesis in the plastid and increased galactolipid synthesis from diacylglycerol produced via the ER pathway. The transgenic plants show a higher photosynthetic assimilation rate, suggesting a possible application of this finding in crop improvement.

  17. Arabidopsis protein phosphatase DBP1 nucleates a protein network with a role in regulating plant defense.

    Directory of Open Access Journals (Sweden)

    José Luis Carrasco

    Full Text Available Arabidopsis thaliana DBP1 belongs to the plant-specific family of DNA-binding protein phosphatases. Although recently identified as a novel host factor mediating susceptibility to potyvirus, little is known about DBP1 targets and partners and the molecular mechanisms underlying its function. Analyzing changes in the phosphoproteome of a loss-of-function dbp1 mutant enabled the identification of 14-3-3λ isoform (GRF6, a previously reported DBP1 interactor, and MAP kinase (MAPK MPK11 as components of a small protein network nucleated by DBP1, in which GRF6 stability is modulated by MPK11 through phosphorylation, while DBP1 in turn negatively regulates MPK11 activity. Interestingly, grf6 and mpk11 loss-of-function mutants showed altered response to infection by the potyvirus Plum pox virus (PPV, and the described molecular mechanism controlling GRF6 stability was recapitulated upon PPV infection. These results not only contribute to a better knowledge of the biology of DBP factors, but also of MAPK signalling in plants, with the identification of GRF6 as a likely MPK11 substrate and of DBP1 as a protein phosphatase regulating MPK11 activity, and unveils the implication of this protein module in the response to PPV infection in Arabidopsis.

  18. Arabidopsis female gametophyte gene expression map reveals similarities between plant and animal gametes.

    Science.gov (United States)

    Wuest, Samuel E; Vijverberg, Kitty; Schmidt, Anja; Weiss, Manuel; Gheyselinck, Jacqueline; Lohr, Miriam; Wellmer, Frank; Rahnenführer, Jörg; von Mering, Christian; Grossniklaus, Ueli

    2010-03-23

    The development of multicellular organisms is controlled by differential gene expression whereby cells adopt distinct fates. A spatially resolved view of gene expression allows the elucidation of transcriptional networks that are linked to cellular identity and function. The haploid female gametophyte of flowering plants is a highly reduced organism: at maturity, it often consists of as few as three cell types derived from a common precursor [1, 2]. However, because of its inaccessibility and small size, we know little about the molecular basis of cell specification and differentiation in the female gametophyte. Here we report expression profiles of all cell types in the mature Arabidopsis female gametophyte. Differentially expressed posttranscriptional regulatory modules and metabolic pathways characterize the distinct cell types. Several transcription factor families are overrepresented in the female gametophyte in comparison to other plant tissues, e.g., type I MADS domain, RWP-RK, and reproductive meristem transcription factors. PAZ/Piwi-domain encoding genes are upregulated in the egg, indicating a role of epigenetic regulation through small RNA pathways-a feature paralleled in the germline of animals [3]. A comparison of human and Arabidopsis egg cells for enrichment of functional groups identified several similarities that may represent a consequence of coevolution or ancestral gametic features. 2010 Elsevier Ltd. All rights reserved.

  19. Functional Disruption of a Chloroplast Pseudouridine Synthase Desensitizes Arabidopsis Plants to Phosphate Starvation

    Directory of Open Access Journals (Sweden)

    Shan Lu

    2017-08-01

    Full Text Available Phosphate (Pi deficiency is a common nutritional stress of plants in both agricultural and natural ecosystems. Plants respond to Pi starvation in the environment by triggering a suite of biochemical, physiological, and developmental changes that increase survival and growth. The key factors that determine plant sensitivity to Pi starvation, however, are unclear. In this research, we identified an Arabidopsis mutant, dps1, with greatly reduced sensitivity to Pi starvation. The dps1 phenotypes are caused by a mutation in the previously characterized SVR1 (SUPPRESSION OF VARIAGATION 1 gene, which encodes a chloroplast-localized pseudouridine synthase. The mutation of SVR1 results in defects in chloroplast rRNA biogenesis, which subsequently reduces chloroplast translation. Another mutant, rps5, which contains a mutation in the chloroplast ribosomal protein RPS5 and has reduced chloroplast translation, also displayed decreased sensitivity to Pi starvation. Furthermore, wild type plants treated with lincomycin, a chemical inhibitor of chloroplast translation, showed similar growth phenotypes and Pi starvation responses as dps1 and rps5. These results suggest that impaired chloroplast translation desensitizes plants to Pi starvation. Combined with previously published results showing that enhanced leaf photosynthesis augments plant responses to Pi starvation, we propose that the decrease in responses to Pi starvation in dps1, rps5, and lincomycin-treated plants is due to their reduced demand for Pi input from the environment.

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

    International Nuclear Information System (INIS)

    Pennacchio, M.; Jefferson, L.V.; Havens, K.

    2007-01-01

    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.

  1. The Arabidopsis Golgi-localized GDP-L-fucose transporter is required for plant development

    DEFF Research Database (Denmark)

    Rautengarten, Carsten; Ebert, Berit; Liu, Lifeng

    2016-01-01

    assays, we show that GFT preferentially transports GDP-L-fucose over other nucleotide sugars in vitro, while GFT1-silenced plants are almost devoid of L-fucose in cell wall-derived xyloglucan and rhamnogalacturonan II. Furthermore, these lines display reduced L-fucose content in N-glycan structures......Nucleotide sugar transport across Golgi membranes is essential for the luminal biosynthesis of glycan structures. Here we identify GDP-fucose transporter 1 (GFT1), an Arabidopsis nucleotide sugar transporter that translocates GDP-L-fucose into the Golgi lumen. Using proteo-liposome-based transport...... accompanied by severe developmental growth defects. We conclude that GFT1 is the major nucleotide sugar transporter for import of GDP-L-fucose into the Golgi and is required for proper plant growth and development....

  2. The Arabidopsis Golgi-localized GDP-L-fucose transporter is required for plant development.

    Science.gov (United States)

    Rautengarten, Carsten; Ebert, Berit; Liu, Lifeng; Stonebloom, Solomon; Smith-Moritz, Andreia M; Pauly, Markus; Orellana, Ariel; Scheller, Henrik Vibe; Heazlewood, Joshua L

    2016-07-06

    Nucleotide sugar transport across Golgi membranes is essential for the luminal biosynthesis of glycan structures. Here we identify GDP-fucose transporter 1 (GFT1), an Arabidopsis nucleotide sugar transporter that translocates GDP-L-fucose into the Golgi lumen. Using proteo-liposome-based transport assays, we show that GFT preferentially transports GDP-L-fucose over other nucleotide sugars in vitro, while GFT1-silenced plants are almost devoid of L-fucose in cell wall-derived xyloglucan and rhamnogalacturonan II. Furthermore, these lines display reduced L-fucose content in N-glycan structures accompanied by severe developmental growth defects. We conclude that GFT1 is the major nucleotide sugar transporter for import of GDP-L-fucose into the Golgi and is required for proper plant growth and development.

  3. Arabidopsis ECERIFERUM9 involvement in cuticle formation and maintenance of plant water status

    KAUST Repository

    Lu, Shiyou

    2012-05-25

    Mutation of the ECERIFERUM9 (CER9) gene in Arabidopsis (Arabidopsis thaliana) causes elevated amounts of 18-carbon-length cutin monomers and a dramatic shift in the cuticular wax profile (especially on leaves) toward the very-long-chain free fatty acids tetracosanoic acid (C24) and hexacosanoic acid (C26). Relative to the wild type, cer9 mutants exhibit elevated cuticle membrane thickness over epidermal cells and cuticular ledges with increased occlusion of the stomatal pore. The cuticular phenotypes of cer9 are associated with delayed onset of wilting in plants experiencing water deficit, lower transpiration rates, and improved water use efficiency measured as carbon isotope discrimination. The CER9 protein thus encodes a novel determinant of plant drought tolerance-associated traits, one whose deficiency elevates cutin synthesis, redistributes wax composition, and suppresses transpiration. Map-based cloning identified CER9, and sequence analysis predicted that it encodes an E3 ubiquitin ligase homologous to yeast Doa10 (previously shown to target endoplasmic reticulum proteins for proteasomal degradation). To further elucidate CER9 function, the impact of CER9 deficiency on interactions with other genes was examined using double mutant and transcriptome analyses. For both wax and cutin, cer9 showed mostly additive effects with cer6, long-chain acyl-CoA synthetase1 (lacs1), and lacs2 and revealed its role in early steps of both wax and cutin synthetic pathways. Transcriptome analysis revealed that the cer9 mutation affected diverse cellular processes, with primary impact on genes associated with diverse stress responses. The discovery of CER9 lays new groundwork for developing novel cuticle-based strategies for improving the drought tolerance and water use efficiency of crop plants. © 2012 American Society of Plant Biologists. All Rights Reserved.

  4. Plants experiencing chronic internal exposure to ionizing radiation exhibit higher frequency of homologous recombination than acutely irradiated plants

    Energy Technology Data Exchange (ETDEWEB)

    Kovalchuk, O.; Kovalchuk, I.; Hohn, B. [Friedrich Miescher Institute, P.O. Box 2543, CH-4002 Basel (Switzerland); Arkhipov, A. [Chernobyl Scientific and Technical Center of International Research, Shkolnaya Str. 6, 255620 Chernobyl (Ukraine); Barylyak, I.; Karachov, I. [Ukrainian Scientific Genetics Center, Popudrenko Str. 50, 253660 Kiev (Ukraine); Titov, V. [Ivano-Frankivsk State Medical Academy, Galitska Str.2, 284000 Ivano-Frankivsk (Ukraine)

    2000-04-03

    Ionizing radiation (IR) is a known mutagen responsible for causing DNA strand breaks in all living organisms. Strand breaks thus created can be repaired by different mechanisms, including homologous recombination (HR), one of the key mechanisms maintaining genome stability [A. Britt, DNA damage and repair in plants, Annu. Rev. Plant. Phys. Plant Mol. Biol., 45 (1996) 75-100; H. Puchta, B. Hohn, From centiMorgans to basepairs: homologous recombination in plants, Trends Plant Sci., 1 (1996) 340-348.]. Acute or chronic exposure to IR may have different influences on the genome integrity. Although in a radioactively contaminated environment plants are mostly exposed to chronic pollution, evaluation of both kinds of influences is important. Estimation of the frequency of HR in the exposed plants may serve as an indication of genome stability. We used previously generated Arabidopsis thaliana and Nicotiana tabacum plants, transgenic for non-active versions of the {beta}-glucoronidase gene (uidA) [P. Swoboda, S. Gal, B. Hohn, H. Puchta, Intrachromosomal homologous recombination in whole plants, EMBO J., 13 (1994) 484-489; H. Puchta, P. Swoboda, B. Hohn, Induction of homologous DNA recombination in whole plants, Plant, 7 (1995) 203-210.] serving as a recombination substrate, to study the influence of acute and chronic exposure to IR on the level of HR as example of genome stability in plants. Exposure of seeds and seedlings to 0.1 to 10.0 Gy 60Co resulted in increased HR frequency, although the effect was more pronounced in seedlings. For the study of the influence of chronic exposure to IR, plants were grown on two chemically different types of soils, each artificially contaminated with equal amounts of 137Cs. We observed a strong and significant correlation between the frequency of HR in plants, the radioactivity of the soil samples and the doses of radiation absorbed by plants (in all cases r0.9, n=6, P<0.05). In addition, we noted that plants grown in soils with

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

    Science.gov (United States)

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

    2017-08-01

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

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

    International Nuclear Information System (INIS)

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

    2008-06-01

    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 H 2 O 2 scavenging activity in leaves were applied

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

    Science.gov (United States)

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

    2007-10-01

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

  8. 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.

  9. Constitutive over-expression of rice chymotrypsin protease inhibitor gene OCPI2 results in enhanced growth, salinity and osmotic stress tolerance of the transgenic Arabidopsis plants.

    Science.gov (United States)

    Tiwari, Lalit Dev; Mittal, Dheeraj; Chandra Mishra, Ratnesh; Grover, Anil

    2015-07-01

    Protease inhibitors are involved primarily in defense against pathogens. In recent years, these proteins have also been widely implicated in response of plants to diverse abiotic stresses. Rice chymotrypsin protease inhibitor gene OCPI2 is highly induced under salt and osmotic stresses. The construct containing the complete coding sequence of OCPI2 cloned downstream to CaMV35S promoter was transformed in Arabidopsis and single copy, homozygous transgenic lines were produced. The transgenic plants exhibited significantly enhanced tolerance to NaCl, PEG and mannitol stress as compared to wild type plants. Importantly, the vegetative and reproductive growth of transgenic plants under unstressed, control conditions was also enhanced: transgenic plants were more vigorous than wild type, resulting into higher yield in terms of silique number. The RWC values and membrane stability index of transgenic in comparison to wild type plants was higher. Higher proline content was observed in the AtOCPI2 lines, which was associated with higher transcript expression of pyrroline-5-carboxylate synthase and lowered levels of proline dehydrogenase genes. The chymotrypsin protease activities were lower in the transgenic as against wild type plants, under both unstressed, control as well as stressed conditions. It thus appears that rice chymotrypsin protease inhibitor gene OCPI2 is a useful candidate gene for genetic improvement of plants against salt and osmotic stress. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  10. Genotype-environment interactions affect flower and fruit herbivory and plant chemistry of Arabidopsis thaliana in a transplant experiment

    NARCIS (Netherlands)

    Mosleh Arany, A.; de Jong, T.; Kim, H.K.; Van Dam, N.M.; Choi, Y.L.; van Mil, H.G.J.; Verpoorte, R.; van der Meijden, E.

    2009-01-01

    Large differences exist in flower and fruit herbivory between dune and inland populations of plants of Arabidopsis thaliana (Brassicaceae). Two specialist weevils Ceutorhynchus atomus and C. contractus (Curculionidae) and their larvae are responsible for this pattern in herbivory. We test, by means

  11. Quantification of tomato and Arabidopsis mobile RNAs trafficking into the parasitic plant Cuscuta pentagona.

    Science.gov (United States)

    LeBlanc, Megan; Kim, Gunjune; Patel, Beneeta; Stromberg, Verlyn; Westwood, James

    2013-12-01

    The cross-species movement of mRNA from hosts to the parasitic plant Cuscuta pentagona has been reported previously, but has not been characterized quantitatively or with attention to uptake patterns and the fate of specific mRNAs. Real-time PCR and RNA-Seq approaches were used to identify and characterize mobile transcripts from tomato and Arabidopsis hosts into C. pentagona. Tomato transcripts of Gibberellic Acid Insensitive (SlGAI) and Cathepsin D Proteinase Inhibitor (SlPI) differed significantly in the rate of uptake into the parasite, but were then distributed over the length of the parasite shoot. When parasite shoots were detached from the hosts, the SlPI transcript concentrations in the parasite showed the greatest decrease within the first 8 h. Arabidopsis transcripts also varied in mobility into the parasite, and assay of specific regions of a Salt-inducible Zinc Finger Protein (AtSZF1) transcript revealed distinct patterns of abundance in the parasite. The uptake and distribution of host mRNAs into C. pentagona appears to vary among mRNAs, and perhaps even with the region of the mRNA under investigation. We propose that mRNAs traffic into the parasite via multiple routes, or that other mechanisms for selective uptake and mobility exist between host and parasite. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  12. The Arabidopsis NPR1 Protein Is a Receptor for the Plant Defense Hormone Salicylic Acid

    Directory of Open Access Journals (Sweden)

    Yue Wu

    2012-06-01

    Full Text Available Salicylic acid (SA is an essential hormone in plant immunity, but its receptor has remained elusive for decades. The transcriptional coregulator NPR1 is central to the activation of SA-dependent defense genes, and we previously found that Cys521 and Cys529 of Arabidopsis NPR1's transactivation domain are critical for coactivator function. Here, we demonstrate that NPR1 directly binds SA, but not inactive structural analogs, with an affinity similar to that of other hormone-receptor interactions and consistent with in vivo Arabidopsis SA concentrations. Binding of SA occurs through Cys521/529 via the transition metal copper. Mechanistically, our results suggest that binding of SA causes a conformational change in NPR1 that is accompanied by the release of the C-terminal transactivation domain from the N-terminal autoinhibitory BTB/POZ domain. While NPR1 is already known as a link between the SA signaling molecule and defense-gene activation, we now show that NPR1 is the receptor for SA.

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

    DEFF Research Database (Denmark)

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

    1997-01-01

    cDNA clones encoding two new Arabidopsis thaliana peroxidases, ATP la and ATP 2a, have been identified by searching the Arabidopsis database of expressed sequence tags (dbEST). They represent a novel branch of hitherto uncharacterized plant peroxidases which is only 35% identical in amino acid...

  14. Functional network analysis of genes differentially expressed during xylogenesis in soc1ful woody Arabidopsis plants.

    Science.gov (United States)

    Davin, Nicolas; Edger, Patrick P; Hefer, Charles A; Mizrachi, Eshchar; Schuetz, Mathias; Smets, Erik; Myburg, Alexander A; Douglas, Carl J; Schranz, Michael E; Lens, Frederic

    2016-06-01

    Many plant genes are known to be involved in the development of cambium and wood, but how the expression and functional interaction of these genes determine the unique biology of wood remains largely unknown. We used the soc1ful loss of function mutant - the woodiest genotype known in the otherwise herbaceous model plant Arabidopsis - to investigate the expression and interactions of genes involved in secondary growth (wood formation). Detailed anatomical observations of the stem in combination with mRNA sequencing were used to assess transcriptome remodeling during xylogenesis in wild-type and woody soc1ful plants. To interpret the transcriptome changes, we constructed functional gene association networks of differentially expressed genes using the STRING database. This analysis revealed functionally enriched gene association hubs that are differentially expressed in herbaceous and woody tissues. In particular, we observed the differential expression of genes related to mechanical stress and jasmonate biosynthesis/signaling during wood formation in soc1ful plants that may be an effect of greater tension within woody tissues. Our results suggest that habit shifts from herbaceous to woody life forms observed in many angiosperm lineages could have evolved convergently by genetic changes that modulate the gene expression and interaction network, and thereby redeploy the conserved wood developmental program. © 2016 The Authors. The Plant Journal published by Society for Experimental Biology and John Wiley & Sons Ltd.

  15. 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.

  16. Enhancement of naphthalene tolerance in transgenic Arabidopsis plants overexpressing the ferredoxin-like protein (ADI1) from rice.

    Science.gov (United States)

    Fu, Xiao-Yan; Zhu, Bo; Han, Hong-Juan; Zhao, Wei; Tian, Yong-Sheng; Peng, Ri-He; Yao, Quan-Hong

    2016-01-01

    The ADI1 Arabidopsis plants enhanced tolerance and degradation efficiency to naphthalene and had great potential for phytoremediation of naphthalene in the plant material before composting or harvesting and removal. Naphthalene is a global environmental concern, because this substance is assumed to contribute considerably to human cancer risk. Cleaning up naphthalene contamination in the environment is crucial. Phytoremediation is an efficient technology to clean up contaminants. However, no gene that can efficiently degrade exogenous recalcitrant naphthalene in plants has yet been discovered. Ferredoxin (Fd) is a key player of biological electron transfer reaction in the PAH degradation process. The biochemical pathway for bacterial degradation of naphthalene has been well investigated. In this study, a rice gene, ADI1, which codes for a putative photosynthetic-type Fd, has been transformed into Arabidopsis thaliana. The transgenic Arabidopsis plants enhanced tolerance and degradation efficiency of naphthalene. Compared with wild-type plants, transgenic plants assimilated naphthalene from the culture media faster and removed more of this substance. When taken together, our findings suggest that breeding plants with overexpressed ADI1 gene is an effective strategy to degrade naphthalene in the environment.

  17. Heterologous Expression of Secreted Bacterial BPP and HAP Phytases in Plants Stimulates Arabidopsis thaliana Growth on Phytate

    Directory of Open Access Journals (Sweden)

    Lia R. Valeeva

    2018-02-01

    Full Text Available Phytases are specialized phosphatases capable of releasing inorganic phosphate from myo-inositol hexakisphosphate (phytate, which is highly abundant in many soils. As inorganic phosphorus reserves decrease over time in many agricultural soils, genetic manipulation of plants to enable secretion of potent phytases into the rhizosphere has been proposed as a promising approach to improve plant phosphorus nutrition. Several families of biotechnologically important phytases have been discovered and characterized, but little data are available on which phytase families can offer the most benefits toward improving plant phosphorus intake. We have developed transgenic Arabidopsis thaliana plants expressing bacterial phytases PaPhyC (HAP family of phytases and 168phyA (BPP family under the control of root-specific inducible promoter Pht1;2. The effects of each phytase expression on growth, morphology and inorganic phosphorus accumulation in plants grown on phytate hydroponically or in perlite as the only source of phosphorus were investigated. The most enzymatic activity for both phytases was detected in cell wall-bound fractions of roots, indicating that these enzymes were efficiently secreted. Expression of both bacterial phytases in roots improved plant growth on phytate and resulted in larger rosette leaf area and diameter, higher phosphorus content and increased shoot dry weight, implying that these plants were indeed capable of utilizing phytate as the source of phosphorus for growth and development. When grown on phytate the HAP-type phytase outperformed its BPP-type counterpart for plant biomass production, though this effect was only observed in hydroponic conditions and not in perlite. Furthermore, we found no evidence of adverse side effects of microbial phytase expression in A. thaliana on plant physiology and seed germination. Our data highlight important functional differences between these members of bacterial phytase families and indicate

  18. Heterologous Expression of Secreted Bacterial BPP and HAP Phytases in Plants Stimulates Arabidopsis thaliana Growth on Phytate.

    Science.gov (United States)

    Valeeva, Lia R; Nyamsuren, Chuluuntsetseg; Sharipova, Margarita R; Shakirov, Eugene V

    2018-01-01

    Phytases are specialized phosphatases capable of releasing inorganic phosphate from myo -inositol hexakisphosphate (phytate), which is highly abundant in many soils. As inorganic phosphorus reserves decrease over time in many agricultural soils, genetic manipulation of plants to enable secretion of potent phytases into the rhizosphere has been proposed as a promising approach to improve plant phosphorus nutrition. Several families of biotechnologically important phytases have been discovered and characterized, but little data are available on which phytase families can offer the most benefits toward improving plant phosphorus intake. We have developed transgenic Arabidopsis thaliana plants expressing bacterial phytases PaPhyC (HAP family of phytases) and 168phyA (BPP family) under the control of root-specific inducible promoter Pht1;2 . The effects of each phytase expression on growth, morphology and inorganic phosphorus accumulation in plants grown on phytate hydroponically or in perlite as the only source of phosphorus were investigated. The most enzymatic activity for both phytases was detected in cell wall-bound fractions of roots, indicating that these enzymes were efficiently secreted. Expression of both bacterial phytases in roots improved plant growth on phytate and resulted in larger rosette leaf area and diameter, higher phosphorus content and increased shoot dry weight, implying that these plants were indeed capable of utilizing phytate as the source of phosphorus for growth and development. When grown on phytate the HAP-type phytase outperformed its BPP-type counterpart for plant biomass production, though this effect was only observed in hydroponic conditions and not in perlite. Furthermore, we found no evidence of adverse side effects of microbial phytase expression in A. thaliana on plant physiology and seed germination. Our data highlight important functional differences between these members of bacterial phytase families and indicate that future

  19. Heterologous Expression of Secreted Bacterial BPP and HAP Phytases in Plants Stimulates Arabidopsis thaliana Growth on Phytate

    Science.gov (United States)

    Valeeva, Lia R.; Nyamsuren, Chuluuntsetseg; Sharipova, Margarita R.; Shakirov, Eugene V.

    2018-01-01

    Phytases are specialized phosphatases capable of releasing inorganic phosphate from myo-inositol hexakisphosphate (phytate), which is highly abundant in many soils. As inorganic phosphorus reserves decrease over time in many agricultural soils, genetic manipulation of plants to enable secretion of potent phytases into the rhizosphere has been proposed as a promising approach to improve plant phosphorus nutrition. Several families of biotechnologically important phytases have been discovered and characterized, but little data are available on which phytase families can offer the most benefits toward improving plant phosphorus intake. We have developed transgenic Arabidopsis thaliana plants expressing bacterial phytases PaPhyC (HAP family of phytases) and 168phyA (BPP family) under the control of root-specific inducible promoter Pht1;2. The effects of each phytase expression on growth, morphology and inorganic phosphorus accumulation in plants grown on phytate hydroponically or in perlite as the only source of phosphorus were investigated. The most enzymatic activity for both phytases was detected in cell wall-bound fractions of roots, indicating that these enzymes were efficiently secreted. Expression of both bacterial phytases in roots improved plant growth on phytate and resulted in larger rosette leaf area and diameter, higher phosphorus content and increased shoot dry weight, implying that these plants were indeed capable of utilizing phytate as the source of phosphorus for growth and development. When grown on phytate the HAP-type phytase outperformed its BPP-type counterpart for plant biomass production, though this effect was only observed in hydroponic conditions and not in perlite. Furthermore, we found no evidence of adverse side effects of microbial phytase expression in A. thaliana on plant physiology and seed germination. Our data highlight important functional differences between these members of bacterial phytase families and indicate that future crop

  20. Using Higher-Order Dynamic Bayesian Networks to Model Periodic Data from the Circadian Clock of Arabidopsis Thaliana

    Science.gov (United States)

    Daly, Rónán; Edwards, Kieron D.; O'Neill, John S.; Aitken, Stuart; Millar, Andrew J.; Girolami, Mark

    Modelling gene regulatory networks in organisms is an important task that has recently become possible due to large scale assays using technologies such as microarrays. In this paper, the circadian clock of Arabidopsis thaliana is modelled by fitting dynamic Bayesian networks to luminescence data gathered from experiments. This work differs from previous modelling attempts by using higher-order dynamic Bayesian networks to explicitly model the time lag between the various genes being expressed. In order to achieve this goal, new techniques in preprocessing the data and in evaluating a learned model are proposed. It is shown that it is possible, to some extent, to model these time delays using a higher-order dynamic Bayesian network.

  1. Introduction of tri-antennary N-glycans in Arabidopsis thaliana plants.

    Science.gov (United States)

    Nagels, Bieke; Van Damme, Els J M; Callewaert, Nico; Weterings, Koen

    2012-04-01

    Because the pathway for protein synthesis is largely conserved between plants and animals, plants provide an attractive platform for the cost effective and flexible production of biopharmaceuticals. However, there are some differences in glycosylation between plants and humans that need to be considered before plants can be used as an efficient expression platform. In the presented research the human genes encoding α1,3-mannosyl-β1,4-N-acetylglucosaminyltransferase (GnT-IV) and α1,6-mannosyl-β1,6-N-acetylglucosaminyltransferase (GnT-V) were introduced in the fast cycling model plant Arabidopsis thaliana to synthesize tri-antennary N-glycans. The GnT-IV and -V enzymes were targeted to the Golgi apparatus with plant-specific localization signals. The experiments were performed both in a wild type background, as well as in plants lacking β1,2-xylosyltransferase (XylT) and α1,3-fucosyltransferase (FucT) activity. Glycan analysis of endogenous proteins in the transgenic lines using CE-LIF showed that tri-antennary N-glycans could be produced in the XylT/FucT deficient line, while these structures were not found in the wild type background. Since β-N-acetylhexosaminidases, that remove terminal GlcNAcs, are active in A. thaliana plants, the specificity of these enzymes for different GlcNAc linkages was tested. The results showed that there is no pronounced preference of the A. thaliana hexosaminidases for human-type GlcNAc-linkages. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  2. Increased Rate of NAD Metabolism Shortens Plant Longevity by Accelerating Developmental Senescence in Arabidopsis.

    Science.gov (United States)

    Hashida, Shin-Nosuke; Itami, Taketo; Takahara, Kentaro; Hirabayashi, Takayuki; Uchimiya, Hirofumi; Kawai-Yamada, Maki

    2016-11-01

    NAD is a well-known co-enzyme that mediates hundreds of redox reactions and is the basis of various processes regulating cell responses to different environmental and developmental cues. The regulatory mechanism that determines the amount of cellular NAD and the rate of NAD metabolism remains unclear. We created Arabidopsis thaliana plants overexpressing the NAD synthase (NADS) gene that participates in the final step of NAD biosynthesis. NADS overexpression enhanced the activity of NAD biosynthesis but not the amounts of NAD + , NADH, NADP + or NADPH. However, the amounts of some intermediates were elevated, suggesting that NAD metabolism increased. The NAD redox state was greatly facilitated by an imbalance between NAD generation and degradation in response to bolting. Metabolite profiling and transcriptional analysis revealed that the drastic modulation of NAD redox homeostasis increased tricarboxylic acid flux, causing the ectopic generation of reactive oxygen species. Vascular bundles suffered from oxidative stress, leading to a malfunction in amino acid and organic acid transportation that caused early wilting of the flower stalk and shortened plant longevity, probably due to malnutrition. We concluded that the mechanism regulating the balance between NAD synthesis and degradation is important in the systemic plant response to developmental cues during the growth-phase transition. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  3. Suberized transport barriers in Arabidopsis, barley and rice roots: From the model plant to crop species.

    Science.gov (United States)

    Kreszies, Tino; Schreiber, Lukas; Ranathunge, Kosala

    2018-02-07

    Water is the most important prerequisite for life and plays a major role during uptake and transport of nutrients. Roots are the plant organs that take up the major part of water, from the surrounding soil. Water uptake is related to the root system architecture, root growth, age and species dependent complex developmental changes in the anatomical structures. The latter is mainly attributed to the deposition of suberized barriers in certain layers of cell walls, such as endo- and exodermis. With respect to water permeability, changes in the suberization of roots are most relevant. Water transport or hydraulic conductivity of roots (Lp r ) can be described by the composite transport model and is known to be very variable between plant species and growth conditions and root developmental states. In this review, we summarize how anatomical structures and apoplastic barriers of roots can diversely affect water transport, comparing the model plant Arabidopsis with crop plants, such as barley and rice. Results comparing the suberin amounts and water transport properties indicate that the common assumption that suberin amount negatively correlates with water and solute transport through roots may not always be true. The composition, microstructure and localization of suberin may also have a great impact on the formation of efficient barriers to water and solutes. Copyright © 2018 The Authors. Published by Elsevier GmbH.. All rights reserved.

  4. Arabidopsis leucine-rich repeat extensin (LRX) proteins modify cell wall composition and influence plant growth.

    Science.gov (United States)

    Draeger, Christian; Ndinyanka Fabrice, Tohnyui; Gineau, Emilie; Mouille, Grégory; Kuhn, Benjamin M; Moller, Isabel; Abdou, Marie-Therese; Frey, Beat; Pauly, Markus; Bacic, Antony; Ringli, Christoph

    2015-06-24

    Leucine-rich repeat extensins (LRXs) are extracellular proteins consisting of an N-terminal leucine-rich repeat (LRR) domain and a C-terminal extensin domain containing the typical features of this class of structural hydroxyproline-rich glycoproteins (HRGPs). The LRR domain is likely to bind an interaction partner, whereas the extensin domain has an anchoring function to insolubilize the protein in the cell wall. Based on the analysis of the root hair-expressed LRX1 and LRX2 of Arabidopsis thaliana, LRX proteins are important for cell wall development. The importance of LRX proteins in non-root hair cells and on the structural changes induced by mutations in LRX genes remains elusive. The LRX gene family of Arabidopsis consists of eleven members, of which LRX3, LRX4, and LRX5 are expressed in aerial organs, such as leaves and stem. The importance of these LRX genes for plant development and particularly cell wall formation was investigated. Synergistic effects of mutations with gradually more severe growth retardation phenotypes in double and triple mutants suggest a similar function of the three genes. Analysis of cell wall composition revealed a number of changes to cell wall polysaccharides in the mutants. LRX3, LRX4, and LRX5, and most likely LRX proteins in general, are important for cell wall development. Due to the complexity of changes in cell wall structures in the lrx mutants, the exact function of LRX proteins remains to be determined. The increasingly strong growth-defect phenotypes in double and triple mutants suggests that the LRX proteins have similar functions and that they are important for proper plant development.

  5. Impact of common cytostatic drugs on pollen fertility in higher plants.

    Science.gov (United States)

    Mišík, Miroslav; Kundi, Michael; Pichler, Clemens; Filipic, Metka; Rainer, Bernhard; Mišíková, Katarina; Nersesyan, Armen; Knasmueller, Siegfried

    2016-08-01

    Cytostatic drugs are among the most toxic chemicals which are produced. Many of them cause damage of the genetic material which may affect the fertility of higher organisms. To study the impact of the widely used anticancer drugs [cisplatin (CisPt), etoposide (Et), and 5-fluorouracil (5-FU)] on the reproduction of higher plants, pollen abortion experiments were conducted with species which belong to major plant families, namely with Tradescantia paludosa (Commelinaceae), Arabidopsis thaliana (Brassicaceae), Chelidonium majus (Papaveraceae), and Alisma plantago-aquatica (Alismataceae). All compounds increased the frequencies of abortive grains. The lowest effective doses were in general in a narrow range (i.e., 1 and 10 mg/kg of dry soil). The effects of the individual drugs were similar in T. paludosa, A. plantago-aquatica, and Ch. majus, while A. thaliana was consistently less sensitive. The highest abortion rate was obtained in most experiments with CisPt, followed by 5-FU and Et. Comparisons of the doses which caused effects in the present experiments in the different species with the predicted environment concentrations and with the levels of the cytostatics which were detected in hospital wastewaters show that the realistic environmental concentrations of the drugs are 4-6 orders of magnitude lower. Therefore, it is unlikely that these drugs affect the fertility of higher plants in aquatic and terrestrial ecosystems.

  6. Molecular Characterization of the Plant Growth Promoting Bacterium Enterobacter sp. SA187 upon Contact with Arabidopsis thaliana

    KAUST Repository

    Alsharif, Wiam

    2018-05-01

    Salt stress is a severe environmental challenge in agriculture, limiting the quality and productivity of the crops around the globe. Plant growth promoting rhizobacteria (PGPR) is proposed as a friendly solution to overcome those challenges. The desert plant endophytic bacterium, Enterobacter sp. SA187 has shown plant growth promotion and salt stress tolerance beneficial effect on the model plant Arabidopsis thaliana in vitro as well as under the field conditions on different crops. SA187 has a distinguished morphology of yellow colonies (SA187Y) that could be due to carotenoid biosynthesis. However, the bacteria tend to lose the yellow color upon incubation with the plants and the colonies turn to white (SA187W). In comparison to SA187Y, SA187W shows 50% reduction on the beneficial impact on A. thaliana fresh and dry weight of root and shoot system. By counting the CFU/plant, we showed that SA187Y and SA187W both have similar colonization rate in both shoots and roots. Under non-salt conditions, optimal bacterial colonization was observed on day 8 after inocubation, however, under the salt stress condition, the optimal colonization was observed at day 4. Moreover, during the time period of the incubation of the SA187Y with the plants, there was a consistent noticeable loss of the yellow color of the colonies. This change in color is only observed eight days after transfer and the number of white colonies increases with the increase of the incubation time. In addition, SA187W was GFP-tagged by Tn7 transposon system and visualized by confocal laser scanning microscopy. The SA187W-GFP colonies have shown a similar colonization pattern as SA187Y-GFP, bacteria were colonizing the differentiation zone and cell elongation zone in the roots. Finally, the gene expression of the carotenoid biosynthesis pathways genes in SA187Y showed an overall higher gene expression compared to SA187W. In conclusion, the color loss seems to affect the beneficial impact of the bacteria on

  7. CBL-CIPK network for calcium signaling in higher plants

    Science.gov (United States)

    Luan, Sheng

    Plants sense their environment by signaling mechanisms involving calcium. Calcium signals are encoded by a complex set of parameters and decoded by a large number of proteins including the more recently discovered CBL-CIPK network. The calcium-binding CBL proteins specifi-cally interact with a family of protein kinases CIPKs and regulate the activity and subcellular localization of these kinases, leading to the modification of kinase substrates. This represents a paradigm shift as compared to a calcium signaling mechanism from yeast and animals. One example of CBL-CIPK signaling pathways is the low-potassium response of Arabidopsis roots. When grown in low-K medium, plants develop stronger K-uptake capacity adapting to the low-K condition. Recent studies show that the increased K-uptake is caused by activation of a specific K-channel by the CBL-CIPK network. A working model for this regulatory pathway will be discussed in the context of calcium coding and decoding processes.

  8. Conserved upstream open reading frames in higher plants

    Directory of Open Access Journals (Sweden)

    Schultz Carolyn J

    2008-07-01

    Full Text Available Abstract Background Upstream open reading frames (uORFs can down-regulate the translation of the main open reading frame (mORF through two broad mechanisms: ribosomal stalling and reducing reinitiation efficiency. In distantly related plants, such as rice and Arabidopsis, it has been found that conserved uORFs are rare in these transcriptomes with approximately 100 loci. It is unclear how prevalent conserved uORFs are in closely related plants. Results We used a homology-based approach to identify conserved uORFs in five cereals (monocots that could potentially regulate translation. Our approach used a modified reciprocal best hit method to identify putative orthologous sequences that were then analysed by a comparative R-nomics program called uORFSCAN to find conserved uORFs. Conclusion This research identified new genes that may be controlled at the level of translation by conserved uORFs. We report that conserved uORFs are rare (

  9. Evaluation of the plant growth-promoting activity of Pseudomonas nitroreducens in Arabidopsis thaliana and Lactuca sativa.

    Science.gov (United States)

    Trinh, Cao Son; Lee, Hyeri; Lee, Won Je; Lee, Seok Jin; Chung, Namhyun; Han, Juhyeong; Kim, Jongyun; Hong, Suk-Whan; Lee, Hojoung

    2018-06-01

    Pseudomonas nitroreducens: strain IHB B 13561 (PnIHB) enhances the growth of Arabidopsis thaliana and Lactuca sativa via the stimulation of cell development and nitrate absorption. Plant growth-promoting rhizobacteria (PGPR) enhance plant development through various mechanisms; they improve the uptake of soil resources by plants to greatly promote plant growth. Here, we used Arabidopsis thaliana seedlings and Lactuca sativa to screen the growth enhancement activities of a purified PGPR, Pseudomonas nitroreducens strain IHB B 13561 (PnIHB). When cocultivated with PnIHB, both species of plants exhibited notably improved growth, particularly in regard to biomass. Quantitative reverse transcription polymerase chain reaction analysis indicated high expression levels of the nitrate transporter genes, especially NRT2.1, which plays a major role in the high-affinity nitrate transport system in roots. Moreover, enhanced activity of the cyclin-B1 promoter was observed when wild-type 'Columbia-0' Arabidopsis seedlings were exposed to PnIHB, whereas upregulation of cyclin-B also occurred in the inoculated lettuce seedlings. Overall, these results suggest that PnIHB improves A. thaliana and L. sativa growth via specific pathways involved in the promotion of cell development and enhancement of nitrate uptake.

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

    Directory of Open Access Journals (Sweden)

    Hasan Murat Aksoy

    2017-01-01

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

  11. Expression of Aluminum-Induced Genes in Transgenic Arabidopsis Plants Can Ameliorate Aluminum Stress and/or Oxidative Stress1

    Science.gov (United States)

    Ezaki, Bunichi; Gardner, Richard C.; Ezaki, Yuka; Matsumoto, Hideaki

    2000-01-01

    To examine the biological role of Al-stress-induced genes, nine genes derived from Arabidopsis, tobacco (Nicotiana tabacum L.), wheat (Triticum aestivum L.), and yeast (Saccharomyces cerevisiae) were expressed in Arabidopsis ecotype Landsberg. Lines containing eight of these genes were phenotypically normal and were tested in root elongation assays for their sensitivity to Al, Cd, Cu, Na, Zn, and to oxidative stresses. An Arabidopsis blue-copper-binding protein gene (AtBCB), a tobacco glutathione S-transferase gene (parB), a tobacco peroxidase gene (NtPox), and a tobacco GDP-dissociation inhibitor gene (NtGDI1) conferred a degree of resistance to Al. Two of these genes, AtBCB and parB, and a peroxidase gene from Arabidopsis (AtPox) also showed increased resistance to oxidative stress induced by diamide, while parB conferred resistance to Cu and Na. Al content of Al-treated root tips was reduced in the four Al-resistant plant lines compared with wild-type Ler-0, as judged by morin staining. All four Al-resistant lines also showed reduced staining of roots with 2′,7′-dichloro fluorescein diacetate (H2DCFDA), an indicator of oxidative stress. We conclude that Al-induced genes can serve to protect against Al toxicity, and also provide genetic evidence for a link between Al stress and oxidative stress in plants. PMID:10712528

  12. Plant cells without detectable plastids are generated in the crumpled leaf mutant of Arabidopsis thaliana.

    Science.gov (United States)

    Chen, Yuling; Asano, Tomoya; Fujiwara, Makoto T; Yoshida, Shigeo; Machida, Yasunori; Yoshioka, Yasushi

    2009-05-01

    Plastids are maintained in cells by proliferating prior to cell division and being partitioned to each daughter cell during cell division. It is unclear, however, whether cells without plastids are generated when plastid division is suppressed. The crumpled leaf (crl) mutant of Arabidopsis thaliana is a plastid division mutant that displays severe abnormalities in plastid division and plant development. We show that the crl mutant contains cells lacking detectable plastids; this situation probably results from an unequal partitioning of plastids to each daughter cell. Our results suggest that crl has a partial defect in plastid expansion, which is suggested to be important in the partitioning of plastids to daughter cells when plastid division is suppressed. The absence of cells without detectable plastids in the accumulation and replication of chloroplasts 6 (arc6) mutant, another plastid division mutant of A. thaliana having no significant defects in plant morphology, suggests that the generation of cells without detectable plastids is one of the causes of the developmental abnormalities seen in crl plants. We also demonstrate that plastids with trace or undetectable amounts of chlorophyll are generated from enlarged plastids by a non-binary fission mode of plastid replication in both crl and arc6.

  13. 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.

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

    Science.gov (United States)

    2013-01-01

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

  15. Behavior of radionuclides and related elements in plants. Screening and characterization of cesium requirement mutants from mutagenized arabidopsis thaliana

    Energy Technology Data Exchange (ETDEWEB)

    Yamagami, Mutsumi; Yanai, Masumi; Hisamatsu, Shunichi; Inaba, Jiro [Inst. for Environmental Sciences, Rokkasho, Aomori (Japan)

    2002-07-01

    We have investigated the effect of climate on the metabolic behavior of various elements in a specific plant. The following items have been examined: the effect of climate conditions including Yamase (prevailing windows from the Pacific Ocean side area of Aomori Prefecture) on the elemental transfer factor of rice, the effect of light conditions on metabolism of elements in a plant, the effect of environmental factors on elemental movements at a cell level, and establishment of a mutant plant strain to obtain elemental requirement. This paper describes the development of a method for screening and characterizing cesium resistance mutants from Arabidopsis thaliana. Arabidopsis is a small herbaceous plant which is used for experimental molecular botany. To isolate mutant in cesium uptake or accumulation, we have devised a screening method using energy-dispersive x-ray microanalysis (EDX) of mutagenized Arabidopsis leaves. The seeds for the selection were M{sub 2} seeds derived from ethyl methane sulfonate (EMS)-treated plants. A double screening method was used to isolate about 50 Cs-resistant mutants. In the first screening experiment, EMS-mutagenized seeds were grown in medium containing 3 mM Cs. The wild type Arabidopsis usually died, but Cs-resistant mutants survived. These were transferred into soil for harvest of first-screening-seeds. In the successive experiment, first-screening-seeds were grown in medium containing 1 mM Cs, and Cs of the leaves was analyzed by EDX. We identified about 50 mutants in Cs uptake or accumulation after screening over 100,000 seedlings. These mutants showed either excessive accumulation of Cs in leaves or an inability to accumulate Cs at a normal concentration. The uptake rates of Cs in those mutants were also examined by using {sup 134}Cs radioactive tracer. (author)

  16. Computational identification of candidate nucleotide cyclases in higher plants

    KAUST Repository

    Wong, Aloysius Tze; Gehring, Christoph A

    2013-01-01

    In higher plants guanylyl cyclases (GCs) and adenylyl cyclases (ACs) cannot be identified using BLAST homology searches based on annotated cyclic nucleotide cyclases (CNCs) of prokaryotes, lower eukaryotes, or animals. The reason is that CNCs

  17. Genes of the most conserved WOX clade in plants affect root and flower development in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Moreau Hervé

    2008-10-01

    Full Text Available Abstract Background The Wuschel related homeobox (WOX family proteins are key regulators implicated in the determination of cell fate in plants by preventing cell differentiation. A recent WOX phylogeny, based on WOX homeodomains, showed that all of the Physcomitrella patens and Selaginella moellendorffii WOX proteins clustered into a single orthologous group. We hypothesized that members of this group might preferentially share a significant part of their function in phylogenetically distant organisms. Hence, we first validated the limits of the WOX13 orthologous group (WOX13 OG using the occurrence of other clade specific signatures and conserved intron insertion sites. Secondly, a functional analysis using expression data and mutants was undertaken. Results The WOX13 OG contained the most conserved plant WOX proteins including the only WOX detected in the highly proliferating basal unicellular and photosynthetic organism Ostreococcus tauri. A large expansion of the WOX family was observed after the separation of mosses from other land plants and before monocots and dicots have arisen. In Arabidopsis thaliana, AtWOX13 was dynamically expressed during primary and lateral root initiation and development, in gynoecium and during embryo development. AtWOX13 appeared to affect the floral transition. An intriguing clade, represented by the functional AtWOX14 gene inside the WOX13 OG, was only found in the Brassicaceae. Compared to AtWOX13, the gene expression profile of AtWOX14 was restricted to the early stages of lateral root formation and specific to developing anthers. A mutational insertion upstream of the AtWOX14 homeodomain sequence led to abnormal root development, a delay in the floral transition and premature anther differentiation. Conclusion Our data provide evidence in favor of the WOX13 OG as the clade containing the most conserved WOX genes and established a functional link to organ initiation and development in Arabidopsis, most

  18. Arabidopsis cryptochrome 1 is a soluble protein mediating blue light-dependent regulation of plant growth and development

    International Nuclear Information System (INIS)

    Lin ChenTao; Ahmad, M.; Cashmore, A.R.

    1996-01-01

    Cryptochrome 1 (CRY1) is a flavin-type blue type receptor of Arabidopsis thaliana which mediates inhibition of hypocotyl elongation. In the work described in this report it is demonstrated that CRY1 is a soluble protein expressed in both young seedlings grown either in the dark or under light, and in different organs of adult plants. The functional role of CRY1 was further investigated using transgenic Arabidopsis plants overexpressing CRY1. It is demonstrated that overexpression of CRY1 resulted in hypersensitivity to blue, UV-A, and green light for the inhibition of hypocotyl elongation response. Transgenic plants overexpressing CRY1 also exhibited a dwarf phenotype with reduced size in almost every organ. This was in keeping with the previous observation of reciprocal alterations found in hy4 mutant plants and is consistent with a hypothesis that CRY1 mediates a light-dependent process resulting in a general inhibitory effect on plant growth. In addition, transgenic plants overexpressing CRY1 showed increased anthocyanin accumulation in response to blue, UV-A, and green light in a fluence rate-dependent manner. This increase in anthocyanin accumulation in transgenic plants was shown to be concomitant with increased blue light-induction of CHS gene expression. It is concluded that CRY1 is a photoreceptor mediating blue light-dependent regulation of gene expression in addition to its affect on plant growth. (author)

  19. Carbon partitioning in Arabidopsis thaliana is a dynamic process controlled by the plants metabolic status and its circadian clock

    Science.gov (United States)

    Kölling, Katharina; Thalmann, Matthias; Müller, Antonia; Jenny, Camilla; Zeeman, Samuel C

    2015-01-01

    Abstract Plant growth involves the coordinated distribution of carbon resources both towards structural components and towards storage compounds that assure a steady carbon supply over the complete diurnal cycle. We used 14CO2 labelling to track assimilated carbon in both source and sink tissues. Source tissues exhibit large variations in carbon allocation throughout the light period. The most prominent change was detected in partitioning towards starch, being low in the morning and more than double later in the day. Export into sink tissues showed reciprocal changes. Fewer and smaller changes in carbon allocation occurred in sink tissues where, in most respects, carbon was partitioned similarly, whether the sink leaf assimilated it through photosynthesis or imported it from source leaves. Mutants deficient in the production or remobilization of leaf starch exhibited major alterations in carbon allocation. Low-starch mutants that suffer from carbon starvation at night allocated much more carbon into neutral sugars and had higher rates of export than the wild type, partly because of the reduced allocation into starch, but also because of reduced allocation into structural components. Moreover, mutants deficient in the plant’s circadian system showed considerable changes in their carbon partitioning pattern suggesting control by the circadian clock. This work focusses on the temporal changes in the allocation and transport of photoassimilates within Arabidopsis rosettes, helping to fill a gap in our understanding of plant growth. Using short pulses of 14C-labelled carbon dioxide, we quantified how much carbon is used for growth and how much is stored as starch for use at night. In source leaves, partitioning is surprisingly dynamic during the day, even though photosynthesis is relatively constant, while in sink leaves, utilisation is more constant. Furthermore, by analysing metabolic mutants and clock mutants, and by manipulating the growth conditions, we show that

  20. A moso bamboo WRKY gene PeWRKY83 confers salinity tolerance in transgenic Arabidopsis plants.

    Science.gov (United States)

    Wu, Min; Liu, Huanlong; Han, Guomin; Cai, Ronghao; Pan, Feng; Xiang, Yan

    2017-09-15

    The WRKY family are transcription factors, involved in plant development, and response to biotic and abiotic stresses. Moso bamboo is an important bamboo that has high ecological, economic and cultural value and is widely distributed in the south of China. In this study, we performed a genome-wide identification of WRKY members in moso bamboo and identified 89 members. By comparative analysis in six grass genomes, we found the WRKY gene family may have experienced or be experiencing purifying selection. Based on relative expression levels among WRKY IIc members under three abiotic stresses, PeWRKY83 functioned as a transcription factor and was selected for detailed analysis. The transgenic Arabidopsis of PeWRKY83 showed superior physiological properties compared with the WT under salt stress. Overexpression plants were less sensitive to ABA at both germination and postgermination stages and accumulated more endogenous ABA under salt stress conditions. Further studies demonstrated that overexpression of PeWRKY83 could regulate the expression of some ABA biosynthesis genes (AtAAO3, AtNCED2, AtNCED3), signaling genes (AtABI1, AtPP2CA) and responsive genes (AtRD29A, AtRD29B, AtABF1) under salt stress. Together, these results suggested that PeWRKY83 functions as a novel WRKY-related TF which plays a positive role in salt tolerance by regulating stress-induced ABA synthesis.

  1. The evolutionary response of plants to increased UV-B radiation: Field studies with Arabidopsis thaliana

    International Nuclear Information System (INIS)

    Trumbull, V.L.; Paige, K.N.

    1995-01-01

    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

  2. The role of microRNA399 and sucrose in physiological responses to phosphate deficiency in Arabidopsis thalina plant

    Directory of Open Access Journals (Sweden)

    Farzaneh Mohammadsaleh

    2015-03-01

    Full Text Available microRNAs (miRNAs are noncoding small RNAs that generally function as posttranscriptional negative regulators. The miRNAs play a direct role in plant responses to many types of environmental stresses. For example miR399 had a role in response to Pi deficiency. The aim of this study was to investigate the role of miR399 and sucrose in some physiological responses of Arabidopsis thaliana plants to phosphate deficiency. Therefore, miR399-overexpressing transgenic and wild type Arabidopsis plants were used. The plant seeds were cultured on the Suc+Pi+ (S+P+, Suc-Pi+ (S-P+, Suc+Pi- (S+P- and Suc-Pi- (S-P- media. Pi+ and Pi- refer to 1.2 mM and 10 µM Pi, respectively and Suc+ or Suc- are media culture with 1% sucrose or without. The results showed that sucrose and miR399 had a dramatic effect on root architecture so that primary root length and its branches on S-P+ medium were significantly reduced in over expressed as compared with wild type plants. The highest anthocyanin and starch accumulation was achieved in S+P- media in both plant types. However, miR399 over expression was resulted in significant rise in anthocyanin accumulation on S-P- medium in transgenic relative to wild type plants. In addition, miR399 was resulted in significant rise in free phosphorous level in all types' media. compared to wild type. These results were probably due to the role of sucrose and miR399 in signalling pathway during phosphate starvation in Arabidopsis plant.

  3. 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

  4. TRANSPARENT TESTA GLABRA 1 ubiquitously regulates plant growth and development from Arabidopsis to foxtail millet (Setaria italica).

    Science.gov (United States)

    Liu, Kaige; Qi, Shuanghui; Li, Dong; Jin, Changyu; Gao, Chenhao; Duan, Shaowei; Feng, Baili; Chen, Mingxun

    2017-01-01

    TRANSPARENT TESTA GLABRA 1 of Arabidopsis thaliana (AtTTG1) is a WD40 repeat transcription factor that plays multiple roles in plant growth and development, particularly in seed metabolite production. In the present study, to determine whether SiTTG1 of the phylogenetically distant monocot foxtail millet (Setaria italica) has similar functions, we used transgenic Arabidopsis and Nicotiana systems to explore its activities. We found that SiTTG1 functions as a transcription factor. Overexpression of the SiTTG1 gene rescued many of the mutant phenotypes in Arabidopsis ttg1-13 plants. Additionally, SiTTG1 overexpression fully corrected the reduced expression of mucilage biosynthetic genes, and the induced expression of genes involved in accumulation of seed fatty acids and storage proteins in developing seeds of ttg1-13 plants. Ectopic expression of SiTTG1 restored the sensitivity of the ttg1-13 mutant to salinity and high glucose stresses during germination and seedling establishment, and restored altered expression levels of some stress-responsive genes in ttg1-13 seedlings to the wild type level under salinity and glucose stresses. Our results provide information that will be valuable for understanding the function of TTG1 from monocot to dicot species and identifying a promising target for genetic manipulation of foxtail millet to improve the amount of seed metabolites. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  5. Arabidopsis ECERIFERUM9 involvement in cuticle formation and maintenance of plant water status

    KAUST Repository

    Lu, Shiyou; Zhao, Huayan; Des Marais, David L.; Parsons, Eugene P.; Wen, Xiaoxue; Xu, Xiaojing; Bangarusamy, Dhinoth Kumar; Wang, Guangchao; Rowland, Owen; Juenger, Thomas E.; Bressan, Ray Anthony; Jenks, Matthew A.

    2012-01-01

    Mutation of the ECERIFERUM9 (CER9) gene in Arabidopsis (Arabidopsis thaliana) causes elevated amounts of 18-carbon-length cutin monomers and a dramatic shift in the cuticular wax profile (especially on leaves) toward the very-long-chain free fatty

  6. Overexpressing Exogenous 5-Enolpyruvylshikimate-3-Phosphate Synthase (EPSPS Genes Increases Fecundity and Auxin Content of Transgenic Arabidopsis Plants

    Directory of Open Access Journals (Sweden)

    Jia Fang

    2018-02-01

    Full Text Available Transgenic glyphosate-tolerant plants overproducing EPSPS (5-enolpyruvylshikimate-3-phosphate synthase may exhibit enhanced fitness in glyphosate-free environments. If so, introgression of transgenes overexpressing EPSPS into wild relative species may lead to increased competitiveness of crop-wild hybrids, resulting in unpredicted environmental impact. Assessing fitness effects of transgenes overexpressing EPSPS in a model plant species can help address this question, while elucidating how overproducing EPSPS affects the fitness-related traits of plants. We produced segregating T2 and T3Arabidopsis thaliana lineages with or without a transgene overexpressing EPSPS isolated from rice or Agrobacterium (CP4. For each of the three transgenes, we compared glyphosate tolerance, some fitness-related traits, and auxin (indole-3-acetic acid content in transgene-present, transgene-absent, empty vector (EV, and parental lineages in a common-garden experiment. We detected substantially increased glyphosate tolerance in T2 plants of transgene-present lineages that overproduced EPSPS. We also documented significant increases in fecundity, which was associated with increased auxin content in T3 transgene-present lineages containing rice EPSPS genes, compared with their segregating transgene-absent lineages, EV, and parental controls. Our results from Arabidopsis with nine transgenic events provide a strong support to the hypothesis that transgenic plants overproducing EPSPS can benefit from a fecundity advantage in glyphosate-free environments. Stimulated biosynthesis of auxin, an important plant growth hormone, by overproducing EPSPS may play a role in enhanced fecundity of the transgenic Arabidopsis plants. The obtained knowledge is useful for assessing environmental impact caused by introgression of transgenes overproducing EPSPS from any GE crop into populations of its wild relatives.

  7. Overexpressing Exogenous 5-Enolpyruvylshikimate-3-Phosphate Synthase (EPSPS) Genes Increases Fecundity and Auxin Content of Transgenic Arabidopsis Plants.

    Science.gov (United States)

    Fang, Jia; Nan, Peng; Gu, Zongying; Ge, Xiaochun; Feng, Yu-Qi; Lu, Bao-Rong

    2018-01-01

    Transgenic glyphosate-tolerant plants overproducing EPSPS (5-enolpyruvylshikimate-3-phosphate synthase) may exhibit enhanced fitness in glyphosate-free environments. If so, introgression of transgenes overexpressing EPSPS into wild relative species may lead to increased competitiveness of crop-wild hybrids, resulting in unpredicted environmental impact. Assessing fitness effects of transgenes overexpressing EPSPS in a model plant species can help address this question, while elucidating how overproducing EPSPS affects the fitness-related traits of plants. We produced segregating T 2 and T 3 Arabidopsis thaliana lineages with or without a transgene overexpressing EPSPS isolated from rice or Agrobacterium ( CP4 ). For each of the three transgenes, we compared glyphosate tolerance, some fitness-related traits, and auxin (indole-3-acetic acid) content in transgene-present, transgene-absent, empty vector (EV), and parental lineages in a common-garden experiment. We detected substantially increased glyphosate tolerance in T 2 plants of transgene-present lineages that overproduced EPSPS. We also documented significant increases in fecundity, which was associated with increased auxin content in T 3 transgene-present lineages containing rice EPSPS genes, compared with their segregating transgene-absent lineages, EV, and parental controls. Our results from Arabidopsis with nine transgenic events provide a strong support to the hypothesis that transgenic plants overproducing EPSPS can benefit from a fecundity advantage in glyphosate-free environments. Stimulated biosynthesis of auxin, an important plant growth hormone, by overproducing EPSPS may play a role in enhanced fecundity of the transgenic Arabidopsis plants. The obtained knowledge is useful for assessing environmental impact caused by introgression of transgenes overproducing EPSPS from any GE crop into populations of its wild relatives.

  8. An overview of the gene regulatory network controlling trichome development in the model plant, Arabidopsis

    Directory of Open Access Journals (Sweden)

    Sitakanta ePattanaik

    2014-06-01

    Full Text Available Trichomes are specialized epidermal cells located on aerial parts of plants and are associated with a wide array of biological processes. Trichomes protect plants from adverse conditions including UV light and herbivore attack and are also an important source of a number of phytochemicals. The simple unicellular trichomes of Arabidopsis serve as an excellent model to study molecular mechanism of cell differentiation and pattern formation in plants. The emerging picture suggests that the developmental process is controlled by a transcriptional network involving three major groups of transcription factors: the R2R3 MYB, basic helix-loop-helix (bHLH and WD40 repeat (WDR protein. These regulatory proteins form a trimeric activator complex that positively regulates trichome development. The single repeat R3 MYBs act as negative regulators of trichome development. They compete with the R2R3 MYBs to bind the bHLH factor and form a repressor complex. In addition to activator-repressor mechanism, a depletion mechanism may operate in parallel during trichome development. In this mechanism, the bHLH factor traps the WDR protein which results in depletion of WDR protein in neighboring cells. Consequently, the cells with high levels of bHLH and WDR proteins are developed into trichomes. A group of C2H2 zinc finger TFs has also been implicated in trichome development. Phytohormones, including gibberellins and jasmonic acid, play significant roles in this developmental process. Recently, microRNAs have been shown to be involved in trichome development. Furthermore, it has been demonstrated that the activities of the key regulatory proteins involved in trichome development are controlled by the 26S/ubiquitin proteasome system (UPS, highlighting the complexity of the regulatory network controlling this developmental process. To complement several excellent recent relevant reviews, this review focuses on the transcriptional network and hormonal interplay

  9. 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)

    van de Mortel, Judith E.; Schat, Henk; Moerland, Perry D.; Ver Loren van Themaat, Emiel; van der Ent, Sjoerd; Blankestijn, Hetty; Ghandilyan, Artak; Tsiatsiani, Styliani; Aarts, Mark 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

  10. Heterologous expression of the yeast Tpo1p or Pdr5p membrane transporters in Arabidopsis confers plant xenobiotic tolerance.

    Science.gov (United States)

    Remy, Estelle; Niño-González, María; Godinho, Cláudia P; Cabrito, Tânia R; Teixeira, Miguel C; Sá-Correia, Isabel; Duque, Paula

    2017-07-03

    Soil contamination is a major hindrance for plant growth and development. The lack of effective strategies to remove chemicals released into the environment has raised the need to increase plant resilience to soil pollutants. Here, we investigated the ability of two Saccharomyces cerevisiae plasma-membrane transporters, the Major Facilitator Superfamily (MFS) member Tpo1p and the ATP-Binding Cassette (ABC) protein Pdr5p, to confer Multiple Drug Resistance (MDR) in Arabidopsis thaliana. Transgenic plants expressing either of the yeast transporters were undistinguishable from the wild type under control conditions, but displayed tolerance when challenged with the herbicides 2,4-D and barban. Plants expressing ScTPO1 were also more resistant to the herbicides alachlor and metolachlor as well as to the fungicide mancozeb and the Co 2+ , Cu 2+ , Ni 2+ , Al 3+ and Cd 2+ cations, while ScPDR5-expressing plants exhibited tolerance to cycloheximide. Yeast mutants lacking Tpo1p or Pdr5p showed increased sensitivity to most of the agents tested in plants. Our results demonstrate that the S. cerevisiae Tpo1p and Pdr5p transporters are able to mediate resistance to a broad range of compounds of agricultural interest in yeast as well as in Arabidopsis, underscoring their potential in future biotechnological applications.

  11. Assimilation and transformation of benzene by higher plants

    Energy Technology Data Exchange (ETDEWEB)

    Durmishidze, S V; Ugrekhelidze, D Sh; Dzhikiya, A N

    1974-01-01

    Higher plants are capable of assimilating benzene, the molecules of which are subjected to deep chemical transformations; the products of its metabolism move along the plant. Taking part in total metabolism, carbon atoms of benzene molecules incorporate into composition of low-molecular compounds of the plant cell. The bulk of benzene carbon incorporates into composition of organic acids and a comparatively small part - into composition of amino acids. In the metabolism process benzene carbon localizes mainly in the chloroplasts. Phenol, muconic acid and CO/sub 2/ are isolated and identified from the products of benzene enzymatic oxidation. A range of benzene assimilation by higher plants is extremely wide. 9 references, 5 tables.

  12. Ecological Risk Assessment of Genetically Modified Higher Plants (GMHP)

    DEFF Research Database (Denmark)

    Kjær, C.; Damgaard, C.; Kjellsson, G.

    Preface This publication is a first version of a manual identifying the data needs for ecological risk assessment of genetically modified higher plants (GMHP). It is the intention of the authors to stimulate further discussion of what data are needed in order to conduct a proper ecological risk...... of the project Biotechnology: elements in environmental risk assessment of genetically modified plants. December 1999 Christian Kjær Introduction In ecological risk assessment of transgenic plants, information on a wide range of subjects is needed for an effective and reliable assessment procedure...... in the amendment to the directive. This report suggests a structured way to identify the type of data needed to perform a sound ecological risk assessment for genetically modified higher plants (GMHP). The identified data types are intended to support the evaluation of the following risks: risk of invasion...

  13. Higher Plants in Space: Microgravity Perception, Response, and Adaptation

    Science.gov (United States)

    Zheng, Hui Qiong; Han, Fei; Le, Jie

    2015-11-01

    Microgravity is a major abiotic stress in space. Its effects on plants may depend on the duration of exposure. We focused on two different phases of microgravity responses in space. When higher plants are exposed to short-term (seconds to hours) microgravity, such as on board parabolic flights and sounding rockets, their cells usually exhibit abiotic stress responses. For example, Ca 2+-, lipid-, and pH-signaling are rapidly enhanced, then the production of reactive oxygen species and other radicals increase dramatically along with changes in metabolism and auxin signaling. Under long-term (days to months) microgravity exposure, plants acclimatize to the stress by changing their metabolism and oxidative response and by enhancing other tropic responses. We conclude by suggesting that a systematic analysis of regulatory networks at the molecular level of higher plants is needed to understand the molecular signals in the distinct phases of the microgravity response and adaptation.

  14. Data integration for plant genomics--exemplars from the integration of Arabidopsis thaliana databases.

    Science.gov (United States)

    Lysenko, Artem; Lysenko, Atem; Hindle, Matthew Morritt; Taubert, Jan; Saqi, Mansoor; Rawlings, Christopher John

    2009-11-01

    The development of a systems based approach to problems in plant sciences requires integration of existing information resources. However, the available information is currently often incomplete and dispersed across many sources and the syntactic and semantic heterogeneity of the data is a challenge for integration. In this article, we discuss strategies for data integration and we use a graph based integration method (Ondex) to illustrate some of these challenges with reference to two example problems concerning integration of (i) metabolic pathway and (ii) protein interaction data for Arabidopsis thaliana. We quantify the degree of overlap for three commonly used pathway and protein interaction information sources. For pathways, we find that the AraCyc database contains the widest coverage of enzyme reactions and for protein interactions we find that the IntAct database provides the largest unique contribution to the integrated dataset. For both examples, however, we observe a relatively small amount of data common to all three sources. Analysis and visual exploration of the integrated networks was used to identify a number of practical issues relating to the interpretation of these datasets. We demonstrate the utility of these approaches to the analysis of groups of coexpressed genes from an individual microarray experiment, in the context of pathway information and for the combination of coexpression data with an integrated protein interaction network.

  15. Overexpression of Arabidopsis thaliana gibberellic acid 20 oxidase (AtGA20ox) gene enhance the vegetative growth and fiber quality in kenaf (Hibiscus cannabinus L.) plants

    Science.gov (United States)

    Withanage, Samanthi Priyanka; Hossain, Md Aktar; Kumar M., Sures; Roslan, Hairul Azman B; Abdullah, Mohammad Puad; Napis, Suhaimi B.; Shukor, Nor Aini Ab.

    2015-01-01

    Kenaf (Hibiscus cannabinus L.; Family: Malvaceae), is multipurpose crop, one of the potential alternatives of natural fiber for biocomposite materials. Longer fiber and higher cellulose contents are required for good quality biocomposite materials. However, average length of kenaf fiber (2.6 mm in bast and 1.28 mm in whole plant) is below the critical length (4 mm) for biocomposite production. Present study describes whether fiber length and cellulose content of kenaf plants could be enhanced by increasing GA biosynthesis in plants by overexpressing Arabidopsis thaliana Gibberellic Acid 20 oxidase (AtGA20ox) gene. AtGA20ox gene with intron was overexpressed in kenaf plants under the control of double CaMV 35S promoter, followed by in planta transformation into V36 and G4 varieties of kenaf. The lines with higher levels of bioactive GA (0.3–1.52 ng g−1 fresh weight) were further characterized for their morphological and biochemical traits including vegetative and reproductive growth, fiber dimension and chemical composition. Positive impact of increased gibberellins on biochemical composition, fiber dimension and their derivative values were demonstrated in some lines of transgenic kenaf including increased cellulose content (91%), fiber length and quality but it still requires further study to confirm the critical level of this particular bioactive GA in transgenic plants. PMID:26175614

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

    Science.gov (United States)

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

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

  17. Predicting molybdenum toxicity to higher plants: Influence of soil properties

    Energy Technology Data Exchange (ETDEWEB)

    McGrath, S.P., E-mail: steve.mcgrath@bbsrc.ac.u [Soil Science Department, Centre for Soils and Ecosystems Functions, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ (United Kingdom); Mico, C. [Soil Science Department, Centre for Soils and Ecosystems Functions, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ (United Kingdom); Curdy, R. [Laboratory for Environmental Biotechnology (LBE), Swiss Federal Institute of Technology Lausanne (EPFL) Station 6 CH, 1015 Lausanne (Switzerland); Zhao, F.J. [Soil Science Department, Centre for Soils and Ecosystems Functions, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ (United Kingdom)

    2010-10-15

    The effect of soil properties on the toxicity of molybdenum (Mo) to four plant species was investigated. Soil organic carbon or ammonium-oxalate extractable Fe oxides were found to be the best predictors of the 50% effective dose (ED{sub 50}) of Mo in different soils, explaining > 65% of the variance in ED{sub 50} for four species except for ryegrass (26-38%). Molybdenum concentrations in soil solution and consequently plant uptake were increased when soil pH was artificially raised because sorption of Mo to amorphous oxides is greatly reduced at high pH. The addition of sulphate significantly decreased Mo uptake by oilseed rape. For risk assessment, we suggest that Mo toxicity values for plants should be normalised using soil amorphous iron oxide concentrations. - Amorphous iron oxides or organic carbon were found to be the best predictors of the toxicity threshold values of Mo to higher plants on different soils.

  18. Predicting molybdenum toxicity to higher plants: Influence of soil properties

    International Nuclear Information System (INIS)

    McGrath, S.P.; Mico, C.; Curdy, R.; Zhao, F.J.

    2010-01-01

    The effect of soil properties on the toxicity of molybdenum (Mo) to four plant species was investigated. Soil organic carbon or ammonium-oxalate extractable Fe oxides were found to be the best predictors of the 50% effective dose (ED 50 ) of Mo in different soils, explaining > 65% of the variance in ED 50 for four species except for ryegrass (26-38%). Molybdenum concentrations in soil solution and consequently plant uptake were increased when soil pH was artificially raised because sorption of Mo to amorphous oxides is greatly reduced at high pH. The addition of sulphate significantly decreased Mo uptake by oilseed rape. For risk assessment, we suggest that Mo toxicity values for plants should be normalised using soil amorphous iron oxide concentrations. - Amorphous iron oxides or organic carbon were found to be the best predictors of the toxicity threshold values of Mo to higher plants on different soils.

  19. Chlorine-containing natural compounds in higher plants

    DEFF Research Database (Denmark)

    Engvild, Kjeld Christensen

    1986-01-01

    More than 130 chlorine-containing compounds have been isolated from higher plants and ferns; about half are polyacetylenes, thiophenes and sesquiterpene lactones from the Asteraceae. A chlorinated chlorophyll may be an important part of photosystem 1. High biological activity is found in 4...

  20. Higher plant vegetation changes during Pliocene sapropel formation

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Menzel, D.; Schouten, S.; Bergen, P.F. van

    2004-01-01

    The 13C values of higher plant wax C27 33 n-alkanes were determined in three, time-equivalent Pliocene (2.943 Ma) sapropels and homogeneous calcareous ooze from three different sites forming an east-west transect in the eastern Mediterranean Basin in order to study the composition of the vegetation

  1. Functional architecture of higher plant photosystem II supercomplexes

    NARCIS (Netherlands)

    Caffarri, Stefano; Kouril, Roman; Kereiche, Sami; Boekema, Egbert J.; Croce, Roberta; Kereïche, Sami

    2009-01-01

    Photosystem II ( PSII) is a large multiprotein complex, which catalyses water splitting and plastoquinone reduction necessary to transform sunlight into chemical energy. Detailed functional and structural studies of the complex from higher plants have been hampered by the impossibility to purify it

  2. Uptake and distribution of mercury within higher plants

    Energy Technology Data Exchange (ETDEWEB)

    Beauford, W; Barber, J; Barringer, A R

    1977-04-15

    The uptake and distribution of inorganic mercury (HgCl/sub 2/) within higher plants (Pisum sativum and Mentha spicata) was examined using solution culture and radiotracer techniques. Plants were found to tolerate an external level of 1 mgHg/kg of solution but both physiological and biochemical processes were affected at 5 mgHg/kg and 10 mgHg/kg. The uptake of Hg into plants grown in hydroponic solution was a function of external concentration. Over the concentration range considered the accumulation of Hg in the roots was linear on a log-log basis although the uptake of the element into the shoots appeared to be two-phased. The distribution of Hg in plants was asymmetrical with much greater amounts of the element in the roots than the shoots. Although the level of Hg increased generally in plant tissues with increasing external levels, the proportion retained in the roots, relative to the shoots, was constant (approximately 95%). Two binding characteristics of the Hg within plant tissue were detected. A major proportion of Hg was tightly bound, being unaffected by treatment with ethanol and hydrochloric acid. The remaining Hg in the tissue was removed by either water or hydrochloric acid treatment. Cell fractionation indicated that the major binding component of Hg in plant tissues was the cell wall.

  3. Arabidopsis ATP A2 peroxidase. Expression and high-resolution structure of a plant peroxidase with implications for lignification

    DEFF Research Database (Denmark)

    Ostergaard, L; Teilum, K; Mirza, O

    2000-01-01

    Lignins are phenolic biopolymers synthesized by terrestrial, vascular plants for mechanical support and in response to pathogen attack. Peroxidases have been proposed to catalyse the dehydrogenative polymerization of monolignols into lignins, although no specific isoenzyme has been shown...... to be involved in lignin biosynthesis. Recently we isolated an extracellular anionic peroxidase, ATP A2, from rapidly lignifying Arabidopsis cell suspension culture and cloned its cDNA. Here we show that the Atp A2 promoter directs GUS reporter gene expression in lignified tissues of transgenic plants. Moreover......-coumaryl and coniferyl alcohols are preferred by ATP A2, while the oxidation of sinapyl alcohol will be sterically hindered in ATP A2 as well as in all other plant peroxidases due to an overlap with the conserved Pro-139. We suggest ATP A2 is involved in a complex regulation of the covalent cross-linking in the plant...

  4. Action of Gibberellins on Growth and Metabolism of Arabidopsis Plants Associated with High Concentration of Carbon Dioxide1[W

    Science.gov (United States)

    Ribeiro, Dimas M.; Araújo, Wagner L.; Fernie, Alisdair R.; Schippers, Jos H.M.; Mueller-Roeber, Bernd

    2012-01-01

    Although the positive effect of elevated CO2 concentration [CO2] on plant growth is well known, it remains unclear whether global climate change will positively or negatively affect crop yields. In particular, relatively little is known about the role of hormone pathways in controlling the growth responses to elevated [CO2]. Here, we studied the impact of elevated [CO2] on plant biomass and metabolism in Arabidopsis (Arabidopsis thaliana) in relation to the availability of gibberellins (GAs). Inhibition of growth by the GA biosynthesis inhibitor paclobutrazol (PAC) at ambient [CO2] (350 µmol CO2 mol−1) was reverted by elevated [CO2] (750 µmol CO2 mol−1). Thus, we investigated the metabolic adjustment and modulation of gene expression in response to changes in growth of plants imposed by varying the GA regime in ambient and elevated [CO2]. In the presence of PAC (low-GA regime), the activities of enzymes involved in photosynthesis and inorganic nitrogen assimilation were markedly increased at elevated [CO2], whereas the activities of enzymes of organic acid metabolism were decreased. Under ambient [CO2], nitrate, amino acids, and protein accumulated upon PAC treatment; however, this was not the case when plants were grown at elevated [CO2]. These results suggest that only under ambient [CO2] is GA required for the integration of carbohydrate and nitrogen metabolism underlying optimal biomass determination. Our results have implications concerning the action of the Green Revolution genes in future environmental conditions. PMID:23090585

  5. The potential of text mining in data integration and network biology for plant research: a case study on Arabidopsis.

    Science.gov (United States)

    Van Landeghem, Sofie; De Bodt, Stefanie; Drebert, Zuzanna J; Inzé, Dirk; Van de Peer, Yves

    2013-03-01

    Despite the availability of various data repositories for plant research, a wealth of information currently remains hidden within the biomolecular literature. Text mining provides the necessary means to retrieve these data through automated processing of texts. However, only recently has advanced text mining methodology been implemented with sufficient computational power to process texts at a large scale. In this study, we assess the potential of large-scale text mining for plant biology research in general and for network biology in particular using a state-of-the-art text mining system applied to all PubMed abstracts and PubMed Central full texts. We present extensive evaluation of the textual data for Arabidopsis thaliana, assessing the overall accuracy of this new resource for usage in plant network analyses. Furthermore, we combine text mining information with both protein-protein and regulatory interactions from experimental databases. Clusters of tightly connected genes are delineated from the resulting network, illustrating how such an integrative approach is essential to grasp the current knowledge available for Arabidopsis and to uncover gene information through guilt by association. All large-scale data sets, as well as the manually curated textual data, are made publicly available, hereby stimulating the application of text mining data in future plant biology studies.

  6. MicroRNA160 Modulates Plant Development and Heat Shock Protein Gene Expression to Mediate Heat Tolerance in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Jeng-Shane Lin

    2018-02-01

    Full Text Available Global warming is causing a negative impact on plant growth and adversely impacts on crop yield. MicroRNAs (miRNAs are critical in regulating the expression of genes involved in plant development as well as defense responses. The effects of miRNAs on heat-stressed Arabidopsis warrants further investigation. Heat stress increased the expression of miR160 and its precursors but considerably reduced that of its targets, ARF10, ARF16, and ARF17. To study the roles of miR160 during heat stress, transgenic Arabidopsis plants overexpressing miR160 precursor a (160OE and artificial miR160 (MIM160, which mimics an inhibitor of miR160, were created. T-DNA insertion mutants of miR160 targets were also used to examine their tolerances to heat stress. Results presented that overexpressing miR160 improved seed germination and seedling survival under heat stress. The lengths of hypocotyl elongation and rachis were also longer in 160OE than the wild-type (WT plants under heat stress. Interestingly, MIM160 plants showed worse adaption to heat. In addition, arf10, arf16, and arf17 mutants presented similar phenotypes to 160OE under heat stress to advance abilities of thermotolerance. Moreover, transcriptome and qRT-PCR analyses revealed that HSP17.6A, HSP17.6II, HSP21, and HSP70B expression levels were regulated by heat in 160OE, MIM160, arf10, arf16, and arf17 plants. Hence, miR160 altered the expression of the heat shock proteins and plant development to allow plants to survive heat stress.

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

    Science.gov (United States)

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

    2016-01-01

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

  8. Roles of arabidopsis WRKY18, WRKY40 and WRKY60 transcription factors in plant responses to abscisic acid and abiotic stress

    OpenAIRE

    Chen Zhixiang; Xiao Yong; Shi Junwei; Lai Zhibing; Chen Han; Xu Xinping

    2010-01-01

    Abstract Background WRKY transcription factors are involved in plant responses to both biotic and abiotic stresses. Arabidopsis WRKY18, WRKY40, and WRKY60 transcription factors interact both physically and functionally in plant defense responses. However, their role in plant abiotic stress response has not been directly analyzed. Results We report that the three WRKYs are involved in plant responses to abscisic acid (ABA) and abiotic stress. Through analysis of single, double, and triple muta...

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

    Directory of Open Access Journals (Sweden)

    Youli eYao

    2013-03-01

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

  10. Co-overexpressing a Plasma Membrane and a Vacuolar Membrane Sodium/Proton Antiporter Significantly Improves Salt Tolerance in Transgenic Arabidopsis Plants.

    Science.gov (United States)

    Pehlivan, Necla; Sun, Li; Jarrett, Philip; Yang, Xiaojie; Mishra, Neelam; Chen, Lin; Kadioglu, Asim; Shen, Guoxin; Zhang, Hong

    2016-05-01

    The Arabidopsis gene AtNHX1 encodes a vacuolar membrane-bound sodium/proton (Na(+)/H(+)) antiporter that transports Na(+) into the vacuole and exports H(+) into the cytoplasm. The Arabidopsis gene SOS1 encodes a plasma membrane-bound Na(+)/H(+) antiporter that exports Na(+) to the extracellular space and imports H(+) into the plant cell. Plants rely on these enzymes either to keep Na(+) out of the cell or to sequester Na(+) into vacuoles to avoid the toxic level of Na(+) in the cytoplasm. Overexpression of AtNHX1 or SOS1 could improve salt tolerance in transgenic plants, but the improved salt tolerance is limited. NaCl at concentration >200 mM would kill AtNHX1-overexpressing or SOS1-overexpressing plants. Here it is shown that co-overexpressing AtNHX1 and SOS1 could further improve salt tolerance in transgenic Arabidopsis plants, making transgenic Arabidopsis able to tolerate up to 250 mM NaCl treatment. Furthermore, co-overexpression of AtNHX1 and SOS1 could significantly reduce yield loss caused by the combined stresses of heat and salt, confirming the hypothesis that stacked overexpression of two genes could substantially improve tolerance against multiple stresses. This research serves as a proof of concept for improving salt tolerance in other plants including crops. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists.

  11. 3D Plant Cell Architecture of Arabidopsis thaliana (Brassicaceae Using Focused Ion Beam–Scanning Electron Microscopy

    Directory of Open Access Journals (Sweden)

    Bhawana

    2014-06-01

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

  12. Novel Occurrence of Uncommon Polyamines in Higher Plants 1

    Science.gov (United States)

    Kuehn, Glenn D.; Rodriguez-Garay, Benjamin; Bagga, Suman; Phillips, Gregory C.

    1990-01-01

    Diamines and polyamines are ubiquitous components of living cells, and apparently are involved in numerous cellular and physiological processes. Certain “uncommon” polyamines have limited distribution in nature and have been associated primarily with organisms adapted to extreme environments, although the precise function of these polyamines in such organisms is unknown. This article summarizes current knowledge regarding the occurrence in higher plants of the uncommon polyamines related to and including norspermidine and norspermine. A putative biosynthetic pathway to account for the occurrences of these uncommon polyamines in higher plants is presented, with a summary of the supporting evidence indicating the existence of the requisite enzymatic activities in alfalfa, Medicago sativa L. PMID:16667862

  13. Effects of Light Intensity on Development and Chlorophyll Content in the Arabidopsis Mutant Plants with Defects in Photosynthesis

    Directory of Open Access Journals (Sweden)

    E.Yu. Garnik

    2015-12-01

    Full Text Available The developmental stages and adaptability to different light intensity (150 µmol*m-2*s-1 and 100 µmol*m-2*s-1 in Arabidopsis mutant lines with defects of photosynthetic apparatus were analyzed. Plant development in the mutant lines depended on the light intensity to varying degrees. Lines ch1-1 (lack of the chlorophyllide a oxygenase and rtn16 (decreased chlorophyll a and b amounts were the most susceptible to the light decrease. No one of the investigated lines demonstrated chlorophyll a/b rate alteration under the different light conditions. The depleted chlorophyll content has had the major effect on the mutant plants development under the different light conditions. The different chlorophyll a/b rate correlated with the different adaptability of mutant plants to low light.

  14. Inositol trisphosphate receptor in higher plants: is it real?

    Czech Academy of Sciences Publication Activity Database

    Krinke, Ondřej; Novotná, Z.; Valentová, O.; Martinec, Jan

    2007-01-01

    Roč. 58, č. 3 (2007), s. 361-376 ISSN 0022-0957 R&D Projects: GA MŠk(CZ) LC06034 Institutional research plan: CEZ:AV0Z50380511 Source of funding: V - iné verejné zdroje Keywords : Ca2+ signalling * higher plants * inositol trisphosphate receptor Subject RIV: EF - Botanics Impact factor: 3.917, year: 2007

  15. Functional architecture of higher plant photosystem II supercomplexes

    OpenAIRE

    Caffarri, Stefano; Kouřil, Roman; Kereïche, Sami; Boekema, Egbert J; Croce, Roberta

    2009-01-01

    Photosystem II (PSII) is a large multiprotein complex, which catalyses water splitting and plastoquinone reduction necessary to transform sunlight into chemical energy. Detailed functional and structural studies of the complex from higher plants have been hampered by the impossibility to purify it to homogeneity. In this work, homogeneous preparations ranging from a newly identified particle composed by a monomeric core and antenna proteins to the largest C2S2M2 supercomplex were isolated. Ch...

  16. Use of higher plants as screens for toxicity assessment.

    Science.gov (United States)

    Kristen, U

    1997-01-01

    This review deals with the use of entire plants, seedlings, cell suspension cultures and pollen tubes for the estimation of potential toxicity in the environment, and for risk assessment of chemicals and formulations of human relevance. It is shown that the roots of onions and various crop seedlings, as well as in vitro growing pollen tubes of some mono- and dicotyledonous plants, are most frequently used to obtain toxicity data by determination of root and tube growth inhibition. Both roots and pollen tubes are chloroplast free, non-photosynthetic systems and, therefore, with regard to their cytotoxic reactions are closer to vertebrate tissues and cells than are chloroplast-containing plant organs. Root tips and anthers of flower buds are shown to be applicable to genotoxicity screening by microscopic analysis of mitotic or meiotic aberrations during cell division or microspore development, respectively. The processes of mitosis and meiosis are similar in plants and animals. Therefore, meristematic and sporogenic tissues of plants generally show patterns of cytotoxic response similar to those of embryogenic and spermatogenic tissues of vertebrates. The suitability of root tips, cell suspensions and pollen tubes for the investigation of mechanisms of toxic action and for the analysis of structure-activity relationships is also demonstrated. Two plant-based assays, the Allium test and the pollen tube growth test, both currently being evaluated alongside with established mammalian in vivo and in vitro protocols, are emphasized with regard to their potential use as alternatives to animal in vivo toxicity tests. For both assays, preliminary results indicate that the tips of growing roots and the rapidly elongating pollen tubes of certain higher plant species are as reliable as mammalian cell lines for detecting basal cytotoxicity. It is suggested that seeds and pollen grains, in particular, provide easily storable and convenient systems for inexpensive, relatively

  17. Overexpression of a Panax ginseng tonoplast aquaporin alters salt tolerance, drought tolerance and cold acclimation ability in transgenic Arabidopsis plants.

    Science.gov (United States)

    Peng, Yanhui; Lin, Wuling; Cai, Weiming; Arora, Rajeev

    2007-08-01

    Water movement across cellular membranes is regulated largely by a family of water channel proteins called aquaporins (AQPs). Since several abiotic stresses such as, drought, salinity and freezing, manifest themselves via altering water status of plant cells and are linked by the fact that they all result in cellular dehydration, we overexpressed an AQP (tonoplast intrinsic protein) from Panax ginseng, PgTIP1, in transgenic Arabidopsis thaliana plants to test its role in plant's response to drought, salinity and cold acclimation (induced freezing tolerance). Under favorable conditions, PgTIP1 overexpression significantly increased plant growth as determined by the biomass production, and leaf and root morphology. PgTIP1 overexpression had beneficial effect on salt-stress tolerance as indicated by superior growth status and seed germination of transgenic plants under salt stress; shoots of salt-stressed transgenic plants also accumulated greater amounts of Na(+) compared to wild-type plants. Whereas PgTIP1 overexpression diminished the water-deficit tolerance of plants grown in shallow (10 cm deep) pots, the transgenic plants were significantly more tolerant to water stress when grown in 45 cm deep pots. The rationale for this contrasting response, apparently, comes from the differences in the root morphology and leaf water channel activity (speed of dehydration/rehydration) between the transgenic and wild-type plants. Plants overexpressed with PgTIP1 exhibited lower (relative to wild-type control) cold acclimation ability; however, this response was independent of cold-regulated gene expression. Our results demonstrate a significant function of PgTIP1 in growth and development of plant cells, and suggest that the water movement across tonoplast (via AQP) represents a rate-limiting factor for plant vigor under favorable growth conditions and also significantly affect responses of plant to drought, salt and cold stresses.

  18. An endoplasmic reticulum-localized Coffea arabica BURP domain-containing protein affects the response of transgenic Arabidopsis plants to diverse abiotic stresses.

    Science.gov (United States)

    Dinh, Sy Nguyen; Kang, Hunseung

    2017-11-01

    The Coffea arabica BURP domain-containing gene plays an important role in the response of transgenic Arabidopsis plants to abiotic stresses via regulating the level of diverse proteins. Although the functions of plant-specific BURP domain-containing proteins (BDP) have been determined for a few plants, their roles in the growth, development, and stress responses of most plant species, including coffee plant (Coffea arabica), are largely unknown. In this study, the function of a C. arabica BDP, designated CaBDP1, was investigated in transgenic Arabidopsis plants. The expression of CaBDP1 was highly modulated in coffee plants subjected to drought, cold, salt, or ABA. Confocal analysis of CaBDP1-GFP fusion proteins revealed that CaBDP1 is localized in the endoplasmic reticulum. The ectopic expression of CaBDP1 in Arabidopsis resulted in delayed germination of the transgenic plants under abiotic stress and in the presence of ABA. Cotyledon greening and seedling growth of the transgenic plants were inhibited in the presence of ABA due to the upregulation of ABA signaling-related genes like ABI3, ABI4, and ABI5. Proteome analysis revealed that the levels of several proteins are modulated in CaBDP1-expressing transgenic plants. The results of this study underscore the importance of BURP domain proteins in plant responses to diverse abiotic stresses.

  19. Co-overexpressing a Plasma Membrane and a Vacuolar Membrane Sodium/Proton Antiporter Significantly Improves Salt Tolerance in Transgenic Arabidopsis Plants

    Science.gov (United States)

    Pehlivan, Necla; Sun, Li; Jarrett, Philip; Yang, Xiaojie; Mishra, Neelam; Chen, Lin; Kadioglu, Asim; Shen, Guoxin; Zhang, Hong

    2016-01-01

    The Arabidopsis gene AtNHX1 encodes a vacuolar membrane-bound sodium/proton (Na+/H+) antiporter that transports Na+ into the vacuole and exports H+ into the cytoplasm. The Arabidopsis gene SOS1 encodes a plasma membrane-bound Na+/H+ antiporter that exports Na+ to the extracellular space and imports H+ into the plant cell. Plants rely on these enzymes either to keep Na+ out of the cell or to sequester Na+ into vacuoles to avoid the toxic level of Na+ in the cytoplasm. Overexpression of AtNHX1 or SOS1 could improve salt tolerance in transgenic plants, but the improved salt tolerance is limited. NaCl at concentration >200 mM would kill AtNHX1-overexpressing or SOS1-overexpressing plants. Here it is shown that co-overexpressing AtNHX1 and SOS1 could further improve salt tolerance in transgenic Arabidopsis plants, making transgenic Arabidopsis able to tolerate up to 250 mM NaCl treatment. Furthermore, co-overexpression of AtNHX1 and SOS1 could significantly reduce yield loss caused by the combined stresses of heat and salt, confirming the hypothesis that stacked overexpression of two genes could substantially improve tolerance against multiple stresses. This research serves as a proof of concept for improving salt tolerance in other plants including crops. PMID:26985021

  20. Comparative interactomics: analysis of arabidopsis 14-3-3 complexes reveals highly conserved 14-3-3 interactions between humans and plants.

    Science.gov (United States)

    Paul, Anna-Lisa; Liu, Li; McClung, Scott; Laughner, Beth; Chen, Sixue; Ferl, Robert J

    2009-04-01

    As a first step in the broad characterization of plant 14-3-3 multiprotein complexes in vivo, stringent and specific antibody affinity purification was used to capture 14-3-3s together with their interacting proteins from extracts of Arabidopsis cell suspension cultures. Approximately 120 proteins were identified as potential in vivo 14-3-3 interacting proteins by mass spectrometry of the recovered complexes. Comparison of the proteins in this data set with the 14-3-3 interacting proteins from a similar study in human embryonic kidney cell cultures revealed eight interacting proteins that likely represent reasonably abundant, fundamental 14-3-3 interaction complexes that are highly conserved across all eukaryotes. The Arabidopsis 14-3-3 interaction data set was also compared to a yeast in vivo 14-3-3 interaction data set. Four 14-3-3 interacting proteins are conserved in yeast, humans, and Arabidopsis. Comparisons of the data sets based on biochemical function revealed many additional similarities in the human and Arabidopsis data sets that represent conserved functional interactions, while also leaving many proteins uniquely identified in either Arabidopsis or human cells. In particular, the Arabidopsis interaction data set is enriched for proteins involved in metabolism.

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

    Science.gov (United States)

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

    2017-07-01

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

  2. Plant-plant interactions influence developmental phase transitions, grain productivity and root system architecture in Arabidopsis via auxin and PFT1/MED25 signalling.

    Science.gov (United States)

    Muñoz-Parra, Edith; Pelagio-Flores, Ramón; Raya-González, Javier; Salmerón-Barrera, Guadalupe; Ruiz-Herrera, León Francisco; Valencia-Cantero, Eduardo; López-Bucio, José

    2017-09-01

    Transcriptional regulation of gene expression influences plant growth, environmental interactions and plant-plant communication. Here, we report that population density is a key factor for plant productivity and a major root architectural determinant in Arabidopsis thaliana. When grown in soil at varied densities from 1 to 32 plants, high number of individuals decreased stem growth and accelerated senescence, which negatively correlated with total plant biomass and seed production at the completion of the life cycle. Root morphogenesis was also a major trait modulated by plant density, because an increasing number of individuals grown in vitro showed repression of primary root growth, lateral root formation and root hair development while affecting auxin-regulated gene expression and the levels of auxin transporters PIN1 and PIN2. We also found that mutation of the Mediator complex subunit PFT1/MED25 renders plants insensitive to high density-modulated root traits. Our results suggest that plant density is critical for phase transitions, productivity and root system architecture and reveal a role of Mediator in self-plant recognition. © 2017 John Wiley & Sons Ltd.

  3. Consideration of higher seismic loads at existing plants

    Energy Technology Data Exchange (ETDEWEB)

    Liebig, J.; Pellissetti, M.

    2015-07-01

    Because of advancement of methods in probabilistic seismic hazard analysis, plenty of existing plants face higher seismic loads as an obligation from the national authorities. In case of such obligations safety related structures and equipment have to be reevaluated or requalified for the increased seismic loads. The paper provides solutions for different kinds of structures and equipment inside the plant, avoiding cost intensive hardware exchange. Due to higher seismic loads different kinds of structures and equipment inside a plant have to be reevaluated. For civil structures, primary components, mechanical components, distribution lines and electrical and I&C equipment different innovative concepts will be applied to keep structures and equipment qualified for the higher seismic loads. Detailed analysis, including the modeling of non-linear phenomena, or minor structural upgrades are cost competitive, compared to cost intensive hardware exchanges. Several case studies regarding the re-evaluation and requalification of structures and equipment due to higher seismic loads are presented. It is shown how the creation of coupled finite element models and the consistent propagation of acceleration time histories through the soil, building and primary circuit lead to a significant load reduction Electrical and I&C equipment is reinforced by smart upgrades which increase the natural equipment frequencies. Therefore for all devices inside the cabinets the local acceleration will not increase and the seismic qualification will be maintained. The case studies cover both classical deterministic and probabilistic re-evaluations (fragility analysis). Furthermore, the substantial benefits of non-linear limit load evaluation, such as push-over analysis of buildings and limit load analysis of fuel assemblies, are demonstrated. (Author)

  4. Mutation induction by ion beams in higher plants

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Atsushi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2003-04-01

    This review mainly describes study results obtained in the Takasaki ion-beam (IB) irradiation facility (TIARA) on the mutation induction in higher plants. Biological effects like lethality and on budding of IBs (carbon, Ne and Ar) are discussed in relation with their linear energy transfer (LET), relative biological effectiveness and the developmental states in shepherd's-purse and tobacco. Induced mutation by IB are characterized by those findings that the mutation rate by C beam is 1.9 x 10{sup -6}, being 17 times higher than the electron beam, in the shepherd's-purse, that C beam induces larger structural changes than electron beam when examined by molecular mechanism of tt and gl gene mutations, and that mutation spectrum of IB is different from that of {gamma}-ray and is wider. Novel mutants are described on shepherd's-purse (pigment mutants, ultraviolet (UV)-resistant and sensitive ones, and flowering ones), disease-resistant rice, barley and tobacco plants, and flowering plants. IB mutation is possibly useful for solving the problems of environment and foods in future. (N.I.)

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

    DEFF Research Database (Denmark)

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

    2005-01-01

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

  6. Overexpression of ARGOS Genes Modifies Plant Sensitivity to Ethylene, Leading to Improved Drought Tolerance in Both Arabidopsis and Maize[OPEN

    Science.gov (United States)

    Shi, Jinrui; Habben, Jeffrey E.; Archibald, Rayeann L.; Drummond, Bruce J.; Chamberlin, Mark A.; Williams, Robert W.; Lafitte, H. Renee; Weers, Ben P.

    2015-01-01

    Lack of sufficient water is a major limiting factor to crop production worldwide, and the development of drought-tolerant germplasm is needed to improve crop productivity. The phytohormone ethylene modulates plant growth and development as well as plant response to abiotic stress. Recent research has shown that modifying ethylene biosynthesis and signaling can enhance plant drought tolerance. Here, we report novel negative regulators of ethylene signal transduction in Arabidopsis (Arabidopsis thaliana) and maize (Zea mays). These regulators are encoded by the ARGOS gene family. In Arabidopsis, overexpression of maize ARGOS1 (ZmARGOS1), ZmARGOS8, Arabidopsis ARGOS homolog ORGAN SIZE RELATED1 (AtOSR1), and AtOSR2 reduced plant sensitivity to ethylene, leading to enhanced drought tolerance. RNA profiling and genetic analysis suggested that the ZmARGOS1 transgene acts between an ethylene receptor and CONSTITUTIVE TRIPLE RESPONSE1 in the ethylene signaling pathway, affecting ethylene perception or the early stages of ethylene signaling. Overexpressed ZmARGOS1 is localized to the endoplasmic reticulum and Golgi membrane, where the ethylene receptors and the ethylene signaling protein ETHYLENE-INSENSITIVE2 and REVERSION-TO-ETHYLENE SENSITIVITY1 reside. In transgenic maize plants, overexpression of ARGOS genes also reduces ethylene sensitivity. Moreover, field testing showed that UBIQUITIN1:ZmARGOS8 maize events had a greater grain yield than nontransgenic controls under both drought stress and well-watered conditions. PMID:26220950

  7. Gaseous 3-pentanol primes plant immunity against a bacterial speck pathogen, Pseudomonas syringae pv. tomato via salicylic acid and jasmonic acid-dependent signaling pathways in Arabidopsis.

    Science.gov (United States)

    Song, Geun C; Choi, Hye K; Ryu, Choong-Min

    2015-01-01

    3-Pentanol is an active organic compound produced by plants and is a component of emitted insect sex pheromones. A previous study reported that drench application of 3-pentanol elicited plant immunity against microbial pathogens and an insect pest in crop plants. Here, we evaluated whether 3-pentanol and the derivatives 1-pentanol and 2-pentanol induced plant systemic resistance using the in vitro I-plate system. Exposure of Arabidopsis seedlings to 10 μM and 100 nM 3-pentanol evaporate elicited an immune response to Pseudomonas syringae pv. tomato DC3000. We performed quantitative real-time PCR to investigate the 3-pentanol-mediated Arabidopsis immune responses by determining Pathogenesis-Related (PR) gene expression levels associated with defense signaling through salicylic acid (SA), jasmonic acid (JA), and ethylene signaling pathways. The results show that exposure to 3-pentanol and subsequent pathogen challenge upregulated PDF1.2 and PR1 expression. Selected Arabidopsis mutants confirmed that the 3-pentanol-mediated immune response involved SA and JA signaling pathways and the NPR1 gene. Taken together, this study indicates that gaseous 3-pentanol triggers induced resistance in Arabidopsis by priming SA and JA signaling pathways. To our knowledge, this is the first report that a volatile compound of an insect sex pheromone triggers plant systemic resistance against a bacterial pathogen.

  8. A plant small polypeptide is a novel component of DNA-binding protein phosphatase 1-mediated resistance to plum pox virus in Arabidopsis.

    Science.gov (United States)

    Castelló, María José; Carrasco, Jose Luis; Navarrete-Gómez, Marisa; Daniel, Jacques; Granot, David; Vera, Pablo

    2011-12-01

    DNA-binding protein phosphatases (DBPs) have been identified as a novel class of plant-specific regulatory factors playing a role in plant-virus interactions. NtDBP1 from tobacco (Nicotiana tabacum) was shown to participate in transcriptional regulation of gene expression in response to virus infection in compatible interactions, and AtDBP1, its closest relative in the model plant Arabidopsis (Arabidopsis thaliana), has recently been found to mediate susceptibility to potyvirus, one of the most speciose taxa of plant viruses. Here, we report on the identification of a novel family of highly conserved small polypeptides that interact with DBP1 proteins both in tobacco and Arabidopsis, which we have designated DBP-interacting protein 2 (DIP2). The interaction of AtDIP2 with AtDBP1 was demonstrated in vivo by bimolecular fluorescence complementation, and AtDIP2 was shown to functionally interfere with AtDBP1 in yeast. Furthermore, reducing AtDIP2 gene expression leads to increased susceptibility to the potyvirus Plum pox virus and to a lesser extent also to Turnip mosaic virus, whereas overexpression results in enhanced resistance. Therefore, we describe a novel family of conserved small polypeptides in plants and identify AtDIP2 as a novel host factor contributing to resistance to potyvirus in Arabidopsis.

  9. Gaseous 3-pentanol primes plant immunity against a bacterial speck pathogen, Pseudomonas syringae pv. tomato via salicylic acid and jasmonic acid-dependent signaling pathways in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Geun Cheol eSong

    2015-10-01

    Full Text Available 3-Pentanol is an active organic compound produced by plants and is a component of emitted insect sex pheromones. A previous study reported that drench application of 3-pentanol elicited plant immunity against microbial pathogens and an insect pest in crop plants. Here, we evaluated whether 3-pentanol and the derivatives 1-pentanol and 2-pentanol induced plant systemic resistance using the in vitro I-plate system. Exposure of Arabidopsis seedlings to 10 M and 100 nM 3-pentanol evaporate elicited an immune response to Pseudomonas syringae pv. tomato DC3000. We performed quantitative real-time PCR to investigate the 3-pentanol-mediated Arabidopsis immune responses by determining Pathogenesis-Related (PR gene expression levels associated with defense signaling through SA, JA, and ethylene signaling pathways. The results show that exposure to 3-pentanol and subsequent pathogen challenge upregulated PDF1.2 and PR1 expression. Selected Arabidopsis mutants confirmed that the 3-pentanol-mediated immune response involved salicylic acid (SA and jasmonic acid (JA signaling pathways and the NPR1 gene. Taken together, this study indicates that gaseous 3-pentanol triggers induced resistance in Arabidopsis by priming SA and JA signaling pathways. To our knowledge, this is the first report that a volatile compound of an insect sex pheromone triggers plant systemic resistance against a bacterial pathogen.

  10. Cloning higher plants from aseptically cultured tissues and cells

    Science.gov (United States)

    Krikorian, A. D.

    1982-01-01

    A review of aseptic culture methods for higher plants is presented, which focuses on the existing problems that limit or prevent the full realization of cloning plants from free cells. It is shown that substantial progress in clonal multiplication has been made with explanted stem tips or lateral buds which can be stimulated to produce numerous precocious axillary branches. These branches can then be separated or subdivided and induced to root in order to yield populations of genetically and phenotypically uniorm plantlets. Similarly, undifferentiated calluses can sometimes be induced to form shoots and/or roots adventitiously. Although the cell culture techniques required to produce somatic embryos are presently rudimentary, steady advances are being made in learning how to stimulate formation of somatic or adventive embryos from totipotent cells grown in suspension cultures. It is concluded that many problems exist in the producing and growing of totipotent or morphogenetically competent cell suspensions, but the potential benefits are great.

  11. Overexpression of an Arabidopsis heterogeneous nuclear ribonucleoprotein gene, AtRNP1, affects plant growth and reduces plant tolerance to drought and salt stresses

    International Nuclear Information System (INIS)

    Wang, Zhenyu; Zhao, Xiuyang; Wang, Bing; Liu, Erlong; Chen, Ni; Zhang, Wei; Liu, Heng

    2016-01-01

    Heterogeneous nuclear ribonucleoproteins (hnRNPs) participate in diverse regulations of plant growth and environmental stress responses. In this work, an Arabidopsis hnRNP of unknown function, AtRNP1, was investigated. We found that AtRNP1 gene is highly expressed in rosette and cauline leaves, and slightly induced under drought, salt, osmotic and ABA stresses. AtRNP1 protein is localized to both the nucleus and cytoplasm. We performed homologous overexpression of AtRNP1 and found that the transgenic plants showed shortened root length and plant height, and accelerated flowering. In addition, the transgenic plants also showed reduced tolerance to drought, salt, osmotic and ABA stresses. Further studies revealed that under both normal and stress conditions, the proline contents in the transgenic plants are markedly decreased, associated with reduced expression levels of a proline synthase gene and several stress-responsive genes. These results suggested that the overexpression of AtRNP1 negatively affects plant growth and abiotic stress tolerance. - Highlights: • AtRNP1 is a widely expressed gene and its expression is slightly induced under abiotic stresses. • AtRNP1 protein is localized to both the nucleus and cytoplasm. • Overexpression of AtRNP1 affects plant growth. • Overexpression of AtRNP1 reduces plant tolerance to drought and salt stresses. • AtRNP1 overexpression plants show decreased proline accumulation and stress-responsive gene expressions.

  12. Overexpression of an Arabidopsis heterogeneous nuclear ribonucleoprotein gene, AtRNP1, affects plant growth and reduces plant tolerance to drought and salt stresses

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhenyu, E-mail: wzy72609@163.com [Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730030 (China); Zhao, Xiuyang, E-mail: xiuzh@psb.vib-ugent.be [Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730030 (China); Wang, Bing, E-mail: wangbing@ibcas.ac.cn [Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730030 (China); Liu, Erlong, E-mail: liuel14@lzu.edu.cn [Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730030 (China); Chen, Ni, E-mail: 63710156@qq.com [Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730030 (China); Zhang, Wei, E-mail: wzhang1216@yahoo.com [Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai 200444 (China); Liu, Heng, E-mail: hengliu@lzu.edu.cn [Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730030 (China)

    2016-04-01

    Heterogeneous nuclear ribonucleoproteins (hnRNPs) participate in diverse regulations of plant growth and environmental stress responses. In this work, an Arabidopsis hnRNP of unknown function, AtRNP1, was investigated. We found that AtRNP1 gene is highly expressed in rosette and cauline leaves, and slightly induced under drought, salt, osmotic and ABA stresses. AtRNP1 protein is localized to both the nucleus and cytoplasm. We performed homologous overexpression of AtRNP1 and found that the transgenic plants showed shortened root length and plant height, and accelerated flowering. In addition, the transgenic plants also showed reduced tolerance to drought, salt, osmotic and ABA stresses. Further studies revealed that under both normal and stress conditions, the proline contents in the transgenic plants are markedly decreased, associated with reduced expression levels of a proline synthase gene and several stress-responsive genes. These results suggested that the overexpression of AtRNP1 negatively affects plant growth and abiotic stress tolerance. - Highlights: • AtRNP1 is a widely expressed gene and its expression is slightly induced under abiotic stresses. • AtRNP1 protein is localized to both the nucleus and cytoplasm. • Overexpression of AtRNP1 affects plant growth. • Overexpression of AtRNP1 reduces plant tolerance to drought and salt stresses. • AtRNP1 overexpression plants show decreased proline accumulation and stress-responsive gene expressions.

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

    Directory of Open Access Journals (Sweden)

    Hushna Ara Naznin

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

  14. Respective contribution of CML8 and CML9, two arabidopsis calmodulin-like proteins, to plant stress responses.

    Science.gov (United States)

    Zhu, Xiaoyang; Perez, Manon; Aldon, Didier; Galaud, Jean-Philippe

    2017-05-04

    In their natural environment, plants have to continuously face constraints such as biotic and abiotic stresses. To achieve their life cycle, plants have to perceive and interpret the nature, but also the strength of environmental stimuli to activate appropriate physiological responses. Nowadays, it is well established that signaling pathways are crucial steps in the implementation of rapid and efficient plant responses such as genetic reprogramming. It is also reported that rapid raises in calcium (Ca 2+ ) levels within plant cells participate in these early signaling steps and are essential to coordinate adaptive responses. However, to be informative, calcium increases need to be decoded and relayed by calcium-binding proteins also referred as calcium sensors to carry-out the appropriate responses. In a recent study, we showed that CML8, an Arabidopsis calcium sensor belonging to the calmodulin-like (CML) protein family, promotes plant immunity against the phytopathogenic bacteria Pseudomonas syringae pv tomato (strain DC3000). Interestingly, other CML proteins such as CML9 were also reported to contribute to plant immunity using the same pathosystem. In this addendum, we propose to discuss about the specific contribution of these 2 CMLs in stress responses.

  15. Arabidopsis PCaP2 Functions as a Linker Between ABA and SA Signals in Plant Water Deficit Tolerance

    Directory of Open Access Journals (Sweden)

    Xianling Wang

    2018-05-01

    Full Text Available Water stress has a major influence on plant growth, development, and productivity. However, the cross-talk networks involved in drought tolerance are not well understood. Arabidopsis PCaP2 is a plasma membrane-associated Ca2+-binding protein. In this study, we employ qRT-PCR and β-glucuronidase (GUS histochemical staining to demonstrate that PCaP2 expression was strongly induced in roots, cotyledons, true leaves, lateral roots, and whole plants under water deficit conditions. Compared with the wild type (WT plants, PCaP2-overexpressing (PCaP2-OE plants displayed enhanced water deficit tolerance in terms of seed germination, seedling growth, and plant survival status. On the contrary, PCaP2 mutation and reduction via PCaP2-RNAi rendered plants more sensitive to water deficit. Furthermore, PCaP2-RNAi and pcap2 seedlings showed shorter root hairs and lower relative water content compared to WT under normal conditions and these phenotypes were exacerbated under water deficit. Additionally, the expression of PCaP2 was strongly induced by exogenous abscisic acid (ABA and salicylic acid (SA treatments. PCaP2-OE plants showed insensitive to exogenous ABA and SA treatments, in contrast to the susceptible phenotypes of pcap2 and PCaP2-RNAi. It is well-known that SNF1-related kinase 2s (SnRK2s and pathogenesis-related (PRs are major factors that influence plant drought tolerance by ABA- and SA-mediated pathways, respectively. Interestingly, PCaP2 positively regulated the expression of drought-inducible genes (RD29A, KIN1, and KIN2, ABA-mediated drought responsive genes (SnRK2.2, -2.3, -2.6, ABF1, -2, -3, -4, and SA-mediated drought responsive genes (PR1, -2, -5 under water deficit, ABA, or SA treatments. Taken together, our results showed that PCaP2 plays an important and positive role in Arabidopsis water deficit tolerance by involving in response to both ABA and SA signals and regulating root hair growth. This study provides novel insights into the

  16. The Voltage-Dependent Anion Channel 1 (AtVDAC1 Negatively Regulates Plant Cold Responses during Germination and Seedling Development in Arabidopsis and Interacts with Calcium Sensor CBL1

    Directory of Open Access Journals (Sweden)

    Zhi-Yong Li

    2013-01-01

    Full Text Available The voltage-dependent anion channel (VDAC, a highly conserved major mitochondrial outer membrane protein, plays crucial roles in energy metabolism and metabolite transport. However, knowledge about the roles of the VDAC family in plants is limited. In this study, we investigated the expression pattern of VDAC1 in Arabidopsis and found that cold stress promoted the accumulation of VDAC1 transcripts in imbibed seeds and mature plants. Overexpression of VDAC1 reduced tolerance to cold stress in Arabidopsis. Phenotype analysis of VDAC1 T-DNA insertion mutant plants indicated that a vdac1 mutant line had faster germination kinetics under cold treatment and showed enhanced tolerance to freezing. The yeast two-hybrid system revealed that VDAC1 interacts with CBL1, a calcium sensor in plants. Like the vdac1, a cbl1 mutant also exhibited a higher seed germination rate. We conclude that both VDAC1 and CBL1 regulate cold stress responses during seed germination and plant development.

  17. Durum wheat dehydrin (DHN-5) confers salinity tolerance to transgenic Arabidopsis plants through the regulation of proline metabolism and ROS scavenging system.

    Science.gov (United States)

    Saibi, Walid; Feki, Kaouthar; Ben Mahmoud, Rihem; Brini, Faiçal

    2015-11-01

    The wheat dehydrin (DHN-5) gives birth to salinity tolerance to transgenic Arabidopsis plants by the regulation of proline metabolism and the ROS scavenging system. Dehydrins (DHNs) are involved in plant abiotic stress tolerance. In this study, we reported that salt tolerance of transgenic Arabidopsis plants overexpressing durum wheat dehydrin (DHN-5) was closely related to the activation of the proline metabolism enzyme (P5CS) and some antioxidant biocatalysts. Indeed, DHN-5 improved P5CS activity in the transgenic plants generating a significant proline accumulation. Moreover, salt tolerance of Arabidopsis transgenic plants was accompanied by an excellent activation of antioxidant enzymes like catalase (CAT), superoxide dismutase (SOD) and peroxide dismutase (POD) and generation of a lower level of hydrogen peroxide (H2O2) in leaves compared to the wild-type plants. The enzyme activities were enhanced in these transgenic plants in the presence of exogenous proline. Nevertheless, proline accumulation was slightly reduced in transgenic plants promoting chlorophyll levels. All these results suggest the crucial role of DHN-5 in response to salt stress through the activation of enzymes implicated in proline metabolism and in ROS scavenging enzymes.

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

    NARCIS (Netherlands)

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

    2004-01-01

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

  19. Phenotypic analyses of Arabidopsis T-DNA insertion lines and expression profiling reveal that multiple L-type lectin receptor kinases are involved in plant immunity

    NARCIS (Netherlands)

    Wang, Y.; Bouwmeester, K.; Beseh, P.; Shan, W.; Govers, F.

    2014-01-01

    L-type lectin receptor kinases (LecRKs) are membrane-spanning receptor-like kinases with putative roles in biotic and abiotic stress responses and in plant development. In Arabidopsis, 45 LecRKs were identified but their functions are largely unknown. Here, a systematic functional analysis was

  20. MALDI-TOF MS and CE-LIF Fingerprinting of Plant Cell Wall Polysaccharide Digests as a Screening Tool for Arabidopsis Cell Wall Mutants

    NARCIS (Netherlands)

    Westphal, Y.; Schols, H.A.; Voragen, A.G.J.; Gruppen, H.

    2010-01-01

    Cell wall materials derived from leaves and hypocotyls of Arabidopsis mutant and wild type plants have been incubated with a mixture of pure and well-defined pectinases, hemicellulases, and cellulases. The resulting oligosaccharides have been subjected to MALDI-TOF MS and CE-LIF analysis. MALDI-TOF

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

    DEFF Research Database (Denmark)

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

    1996-01-01

    Seedlings of Arabidopsis thaliana were germinated and grown in medium containing ß-glucosyl Yariv reagent (ßGlcY), a synthetic phenyl glycoside that interacts specifically with arabinogalactan-proteins (AGPs), a class of plant cell surface proteoglycans. The effect of ßGlcY on the seedlings...

  2. The Arabidopsis mutant iop1 exhibits induced over-expression of the plant defensin gene PDF1.2 and enhanced pathogen resistance

    NARCIS (Netherlands)

    Penninckx, I.A.M.A.; Eggermont, K.; Schenk, P.M.; Ackerveken, van den G.; Cammue, B.P.A.; Thomma, B.P.H.J.

    2003-01-01

    Jasmonate and ethylene are concomitantly involved in the induction of the Arabidopsis plant defensin gene PDF1.2. To define genes in the signal transduction pathway leading to the induction of PDF1.2, we screened for mutants with induced over-expression of a β-glucuronidase reporter, under the

  3. Cytokinin-Deficient Transgenic Arabidopsis Plants Show Multiple Developmental Alterations Indicating Opposite Functions of Cytokinins in the Regulation of Shoot and Root Meristem Activity

    Czech Academy of Sciences Publication Activity Database

    Werner, T.; Motyka, Václav; Laucou, V.; Smets, R.; Onckelen, H. V.; Schmülling, T.

    2003-01-01

    Roč. 15, č. 11 (2003), s. 2532-2550 ISSN 1040-4651 R&D Projects: GA AV ČR IAA6038002 Institutional research plan: CEZ:AV0Z5038910 Keywords : Transgenic Arabidopsis Plants * Cytokinins * Root Meristem Activity Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 10.679, year: 2003

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

    Science.gov (United States)

    Zheng, Zhi-Liang

    2006-01-01

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

  5. Overexpression of a cotton (Gossypium hirsutum) WRKY gene, GhWRKY34, in Arabidopsis enhances salt-tolerance of the transgenic plants.

    Science.gov (United States)

    Zhou, Li; Wang, Na-Na; Gong, Si-Ying; Lu, Rui; Li, Yang; Li, Xue-Bao

    2015-11-01

    Soil salinity is one of the most serious threats in world agriculture, and often influences cotton growth and development, resulting in a significant loss in cotton crop yield. WRKY transcription factors are involved in plant response to high salinity stress, but little is known about the role of WRKY transcription factors in cotton so far. In this study, a member (GhWRKY34) of cotton WRKY family was functionally characterized. This protein containing a WRKY domain and a zinc-finger motif belongs to group III of cotton WRKY family. Subcellular localization assay indicated that GhWRKY34 is localized to the cell nucleus. Overexpression of GhWRKY34 in Arabidopsis enhanced the transgenic plant tolerance to salt stress. Several parameters (such as seed germination, green cotyledons, root length and chlorophyll content) in the GhWRKY34 transgenic lines were significantly higher than those in wild type under NaCl treatment. On the contrary, the GhWRKY34 transgenic plants exhibited a substantially lower ratio of Na(+)/K(+) in leaves and roots dealing with salt stress, compared with wild type. Growth status of the GhWRKY34 transgenic plants was much better than that of wild type under salt stress. Expressions of the stress-related genes were remarkably up-regulated in the transgenic plants under salt stress, compared with those in wild type. Based on the data presented in this study, we hypothesize that GhWRKY34 as a positive transcription regulator may function in plant response to high salinity stress through maintaining the Na(+)/K(+) homeostasis as well as activating the salt stress-related genes in cells. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  6. Arabidopsis thaliana plants expressing Rift Valley fever virus antigens: Mice exhibit systemic immune responses as the result of oral administration of the transgenic plants.

    Science.gov (United States)

    Kalbina, Irina; Lagerqvist, Nina; Moiane, Bélisario; Ahlm, Clas; Andersson, Sören; Strid, Åke; Falk, Kerstin I

    2016-11-01

    The zoonotic Rift Valley fever virus affects livestock and humans in Africa and on the Arabian Peninsula. The economic impact of this pathogen due to livestock losses, as well as its relevance to public health, underscores the importance of developing effective and easily distributed vaccines. Vaccines that can be delivered orally are of particular interest. Here, we report the expression in transformed plants (Arabidopsis thaliana) of Rift Valley fever virus antigens. The antigens used in this study were the N protein and a deletion mutant of the Gn glycoprotein. Transformed lines were analysed for specific mRNA and protein content by RT-PCR and Western blotting, respectively. Furthermore, the plant-expressed antigens were evaluated for their immunogenicity in mice fed the transgenic plants. After oral intake of fresh transgenic plant material, a proportion of the mice elicited specific IgG antibody responses, as compared to the control animals that were fed wild-type plants and of which none sero-converted. Thus, we show that transgenic plants can be readily used to express and produce Rift Valley Fever virus proteins, and that the plants are immunogenic when given orally to mice. These are promising findings and provide a basis for further studies on edible plant vaccines against the Rift Valley fever virus. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Distribution, congruence, and hotspots of higher plants in China.

    Science.gov (United States)

    Zhao, Lina; Li, Jinya; Liu, Huiyuan; Qin, Haining

    2016-01-11

    Identifying biodiversity hotspots has become a central issue in setting up priority protection areas, especially as financial resources for biological diversity conservation are limited. Taking China's Higher Plants Red List (CHPRL), including Bryophytes, Ferns, Gymnosperms, Angiosperms, as the data source, we analyzed the geographic patterns of species richness, endemism, and endangerment via data processing at a fine grid-scale with an average edge length of 30 km based on three aspects of richness information: species richness, endemic species richness, and threatened species richness. We sought to test the accuracy of hotspots used in identifying conservation priorities with regard to higher plants. Next, we tested the congruence of the three aspects and made a comparison of the similarities and differences between the hotspots described in this paper and those in previous studies. We found that over 90% of threatened species in China are concentrated. While a high spatial congruence is observed among the three measures, there is a low congruence between two different sets of hotspots. Our results suggest that biodiversity information should be considered when identifying biological hotspots. Other factors, such as scales, should be included as well to develop biodiversity conservation plans in accordance with the region's specific conditions.

  8. Reference: 774 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available an essential gene, the disruption of which causes embryonic lethality. Plants carrying a hypomorphic smg7 mu...e progression from anaphase to telophase in the second meiotic division in Arabidopsis. Arabidopsis SMG7 is

  9. Characterization of Arabidopsis thaliana FLAVONOL SYNTHASE 1 (FLS1) -overexpression plants in response to abiotic stress.

    Science.gov (United States)

    Nguyen, Nguyen Hoai; Kim, Jun Hyeok; Kwon, Jaeyoung; Jeong, Chan Young; Lee, Wonje; Lee, Dongho; Hong, Suk-Whan; Lee, Hojoung

    2016-06-01

    Flavonoids are an important group of secondary metabolites that are involved in plant growth and contribute to human health. Many studies have focused on the biosynthesis pathway, biochemical characters, and biological functions of flavonoids. In this report, we showed that overexpression of FLS1 (FLS1-OX) not only altered seed coat color (resulting in a light brown color), but also affected flavonoid accumulation. Whereas fls1-3 mutants accumulated higher anthocyanin levels, FLS1-OX seedlings had lower levels than those of the wild-type. Besides, shoot tissues of FLS1-OX plants exhibited lower flavonol levels than those of the wild-type. However, growth performance and abiotic stress tolerance of FLS1-OX, fls1-3, and wild-type plants were not significantly different. Taken together, FLS1 can be manipulated (i.e., silenced or overexpressed) to redirect the flavonoid biosynthetic pathway toward anthocyanin production without negative effects on plant growth and development. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  10. Mercuric ion reduction and resistance in transgenic Arabidopsis thaliana plants expressing a modified bacterial merA gene.

    Science.gov (United States)

    Rugh, C L; Wilde, H D; Stack, N M; Thompson, D M; Summers, A O; Meagher, R B

    1996-01-01

    With global heavy metal contamination increasing, plants that can process heavy metals might provide efficient and ecologically sound approaches to sequestration and removal. Mercuric ion reductase, MerA, converts toxic Hg2+ to the less toxic, relatively inert metallic mercury (Hg0) The bacterial merA sequence is rich in CpG dinucleotides and has a highly skewed codon usage, both of which are particularly unfavorable to efficient expression in plants. We constructed a mutagenized merA sequence, merApe9, modifying the flanking region and 9% of the coding region and placing this sequence under control of plant regulatory elements. Transgenic Arabidopsis thaliana seeds expressing merApe9 germinated, and these seedlings grew, flowered, and set seed on medium containing HgCl2 concentrations of 25-100 microM (5-20 ppm), levels toxic to several controls. Transgenic merApe9 seedlings evolved considerable amounts of Hg0 relative to control plants. The rate of mercury evolution and the level of resistance were proportional to the steady-state mRNA level, confirming that resistance was due to expression of the MerApe9 enzyme. Plants and bacteria expressing merApe9 were also resistant to toxic levels of Au3+. These and other data suggest that there are potentially viable molecular genetic approaches to the phytoremediation of metal ion pollution. Images Fig. 2 Fig. 3 Fig. 4 PMID:8622910

  11. Transgenerational changes in plant physiology and in transposon expression in response to UV-C stress in Arabidopsis thaliana.

    Science.gov (United States)

    Migicovsky, Zoe; Kovalchuk, Igor

    2014-01-01

    Stress has a negative impact on crop yield by altering a gain in biomass and affecting seed set. Recent reports suggest that exposure to stress also influences the response of the progeny. In this paper, we analyzed seed size, leaf size, bolting time and transposon expression in 2 consecutive generations of Arabidopsis thaliana plants exposed to moderate UV-C stress. Since previous reports suggested a potential role of Dicer-like (DCL) proteins in the establishment of transgenerational response, we used dcl2, dcl3 and dcl4 mutants in parallel with wild-type plants. These studies revealed that leaf number decreased in the progeny of UV-C stressed plants, and bolting occurred later. Transposons were also re-activated in the progeny of stressed plants. Changes in the dcl mutants were less prominent than in wild-type plants. DCL2 and DCL3 appeared to be more important in the transgenerational stress memory than DCL4 because transgenerational changes were less profound in the dcl2 and dcl3 mutants.

  12. Predicted global warming scenarios impact on the mother plant to alter seed dormancy and germination behaviour in Arabidopsis.

    Science.gov (United States)

    Huang, Z; Footitt, S; Tang, A; Finch-Savage, W E

    2018-01-01

    Seed characteristics are key components of plant fitness that are influenced by temperature in their maternal environment, and temperature will change with global warming. To study the effect of such temperature changes, Arabidopsis thaliana plants were grown to produce seeds along a uniquely designed polyethylene tunnel having a thermal gradient reflecting local global warming predictions. Plants therefore experienced the same variations in temperature and light conditions but different mean temperatures. A range of seed-related plant fitness estimates were measured. There were dramatic non-linear temperature effects on the germination behaviour in two contrasting ecotypes. Maternal temperatures lower than 15-16 °C resulted in significantly greater primary dormancy. In addition, the impact of nitrate in the growing media on dormancy was shown only by seeds produced below 15-16 °C. However, there were no consistent effects on seed yield, number, or size. Effects on germination behaviour were shown to be a species characteristic responding to temperature and not time of year. Elevating temperature above this critical value during seed development has the potential to dramatically alter the timing of subsequent seed germination and the proportion entering the soil seed bank. This has potential consequences for the whole plant life cycle and species fitness. © 2017 John Wiley & Sons Ltd.

  13. Zinc tolerance and accumulation in stable cell suspension cultures and in vitro regenerated plants of the emerging model plant Arabidopsis halleri (Brassicaceae).

    Science.gov (United States)

    Vera-Estrella, Rosario; Miranda-Vergara, Maria Cristina; Barkla, Bronwyn J

    2009-03-01

    Arabidopsis halleri is increasingly employed as a model plant for studying heavy metal hyperaccumulation. With the aim of providing valuable tools for studies on cellular physiology and molecular biology of metal tolerance and transport, this study reports the development of successful and highly efficient methods for the in vitro regeneration of A. halleri plants and production of stable cell suspension lines. Plants were regenerated from leaf explants of A. halleri via a three-step procedure: callus induction, somatic embryogenesis and shoot development. Efficiency of callus proliferation and regeneration depended on the initial callus induction media and was optimal in the presence of 1 mg L(-1) 2,4-dichlorophenoxyacetic acid, and 0.05 mg L(-1) benzylaminopurine. Subsequent shoot and root regeneration from callus initiated under these conditions reached levels of 100% efficiency. High friability of the callus supported the development of cell suspension cultures with minimal cellular aggregates. Characterization of regenerated plants and cell cultures determined that they maintained not only the zinc tolerance and requirement of the whole plant but also the ability to accumulate zinc; with plants accumulating up to 50.0 micromoles zinc g(-1) FW, and cell suspension cultures 30.9 micromoles zinc g(-1) DW. Together this work will provide the experimental basis for furthering our knowledge of A. halleri as a model heavy metal hyperaccumulating plant.

  14. The efficiency of Arabidopsis thaliana floral dip transformation is determined not only by the Agrobacterium strain used but also by the physiology and the ecotype of the dipped plant.

    Science.gov (United States)

    Ghedira, Rim; De Buck, Sylvie; Nolf, Jonah; Depicker, Ann

    2013-07-01

    To evaluate the chromosomal background of different Agrobacterium strains on floral dip transformation frequency, eight wild-type Agrobacterium strains, provided by Laboratorium voor Microbiologie Gent (LMG) and classified in different genomic groups, were compared with the commonly used Agrobacterium strains C58C1 Rif(r) (pMP90) and LBA4404 in Arabidopsis thaliana Columbia (Col-0) and C24 ecotypes. The C58C1 Rif(r) chromosomal background in combination with the pMP90 virulence plasmid showed high Col-0 floral dip transformation frequencies (0.76 to 1.57%). LMG201, which is genetically close to the Agrobacterium C58 strain, with the same virulence plasmid showed comparable or even higher transformation frequencies (1.22 to 2.28%), whereas the LBA4404 strain displayed reproducibly lower transformation frequencies (Agrobacterium chromosomal backgrounds had transformation frequencies between those of the C58C1 Rif(r) (pMP90) and LBA4404 reference strains. None of the strains could transform the C24 ecotype with a frequency higher than 0.1%. Strikingly, all Arabidopsis Col-0 floral dip transformation experiments showed a high transformation variability from plant to plant (even more than 50-fold) within and across the performed biological repeats for all analyzed Agrobacterium strains. Therefore, the physiology of the plant and, probably, the availability of competent flowers to be transformed determine, to a large extent, floral dip transformation frequencies.

  15. Functional architecture of higher plant photosystem II supercomplexes.

    Science.gov (United States)

    Caffarri, Stefano; Kouril, Roman; Kereïche, Sami; Boekema, Egbert J; Croce, Roberta

    2009-10-07

    Photosystem II (PSII) is a large multiprotein complex, which catalyses water splitting and plastoquinone reduction necessary to transform sunlight into chemical energy. Detailed functional and structural studies of the complex from higher plants have been hampered by the impossibility to purify it to homogeneity. In this work, homogeneous preparations ranging from a newly identified particle composed by a monomeric core and antenna proteins to the largest C(2)S(2)M(2) supercomplex were isolated. Characterization by biochemical methods and single particle electron microscopy allowed to relate for the first time the supramolecular organization to the protein content. A projection map of C(2)S(2)M(2) at 12 A resolution was obtained, which allowed determining the location and the orientation of the antenna proteins. Comparison of the supercomplexes obtained from WT and Lhcb-deficient plants reveals the importance of the individual subunits for the supramolecular organization. The functional implications of these findings are discussed and allow redefining previous suggestions on PSII energy transfer, assembly, photoinhibition, state transition and non-photochemical quenching.

  16. Features of fatty acid synthesis in higher plants

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, M [Tokyo Univ. (Japan). Coll. of General Education; Nakamura, Y

    1975-07-01

    In the biosynthesis of fatty acid in the presence of /sup 3/H/sub 2/O, /sup 3/H is incorporated into the hydrocarbon chain of the fatty acid. The features in the fatty acid synthesis of higher plants were investigated by applying /sup 3/H/sub 2/O method to the measurement of the ability of spinach leaves synthesizing fatty acid. Sucrose, acetate, pyruvate, PGA, PEP, OAA, citrate, etc. were employed as the substrates of fatty acid synthesis to trace the process of synthesis of each fatty acid. The demand of various cofactors related to the ability of spinach chloroplast fatty acid synthesizing was also examined. Light dependence of the fatty acid synthesis of chloroplast as well as the influences of N,N'-dicyclohexyl carbodiimide, carbonylcyanide-4-trifluoromethoxy phenyl hydrazone and NH/sub 4/Cl were discussed. The results were compared with the reports on the fatty acid synthesis of avocado pear, castor bean, etc.

  17. Divergent regulation of CBF regulon on cold tolerance and plant phenotype in cassava overexpressing Arabidopsis CBF3 gene

    Directory of Open Access Journals (Sweden)

    Dong An

    2016-12-01

    Full Text Available Cassava is a tropical origin plant that is sensitive to chilling stress. In order to understand the CBF cold response pathway, a well-recognized regulatory mechanism in temperate plants, in cassava, overexpression of an Arabidopsis CBF3 gene is studied. This gene renders cassava increasingly tolerant to cold and drought stresses but is associated with retarded plant growth, leaf curling, reduced storage root yield, and reduced anthocyanin accumulation in a transcript abundance-dependent manner. Physiological analysis revealed that the transgenic cassava increased proline accumulation, reduced malondialdehyde production, and electrolyte leakage under cold stress. These transgenic lines also showed high relative water content when faced with drought. The expression of partial CBF-targeted genes in response to cold displayed temporal and spatial variations in the wild-type and transgenic plants: highly inducible in leaves and less altered in apical buds. In addition, anthocyanin accumulation was inhibited by downregulating the expression of genes involved in its biosynthesis and by interplaying between the CBF3 and the endogenous transcription factors. Thus, the heterologous CBF3 modulates the expression of stress-related genes and carries out a series of physiological adjustments under stressful conditions, showing a varied regulation pattern of CBF regulon from that of cassava CBFs.

  18. Phosphate, phytate and phytases in plants: from fundamental knowledge gained in Arabidopsis to potential biotechnological applications in wheat.

    Science.gov (United States)

    Secco, David; Bouain, Nadia; Rouached, Aida; Prom-U-Thai, Chanakan; Hanin, Moez; Pandey, Ajay K; Rouached, Hatem

    2017-11-01

    Phosphorus (P) is an essential macronutrient for all living organisms. In plants, P is taken up from the rhizosphere by the roots mainly as inorganic phosphate (Pi), which is required in large and sufficient quantities to maximize crop yields. In today's agricultural society, crop yield is mostly ensured by the excessive use of Pi fertilizers, a costly practice neither eco-friendly or sustainable. Therefore, generating plants with improved P use efficiency (PUE) is of major interest. Among the various strategies employed to date, attempts to engineer genetically modified crops with improved capacity to utilize phytate (PA), the largest soil P form and unfortunately not taken up by plants, remains a key challenge. To meet these challenges, we need a better understanding of the mechanisms regulating Pi sensing, signaling, transport and storage in plants. In this review, we summarize the current knowledge on these aspects, which are mainly gained from investigations conducted in Arabidopsis thaliana, and we extended it to those available on an economically important crop, wheat. Strategies to enhance the PA use, through the use of bacterial or fungal phytases and other attempts of reducing seed PA levels, are also discussed. We critically review these data in terms of their potential for use as a technology for genetic manipulation of PUE in wheat, which would be both economically and environmentally beneficial.

  19. Exogenous glucosinolate produced by Arabidopsis thaliana has an impact on microbes in the rhizosphere and plant roots.

    Science.gov (United States)

    Bressan, Mélanie; Roncato, Marie-Anne; Bellvert, Floriant; Comte, Gilles; Haichar, Feth Zahar; Achouak, Wafa; Berge, Odile

    2009-11-01

    A specificity of Brassicaceous plants is the production of sulphur secondary metabolites called glucosinolates that can be hydrolysed into glucose and biocidal products. Among them, isothiocyanates are toxic to a wide range of microorganisms and particularly soil-borne pathogens. The aim of this study was to investigate the role of glucosinolates and their breakdown products as a factor of selection on rhizosphere microbial community associated with living Brassicaceae. We used a DNA-stable isotope probing approach to focus on the active microbial populations involved in root exudates degradation in rhizosphere. A transgenic Arabidopsis thaliana line producing an exogenous glucosinolate and the associated wild-type plant associated were grown under an enriched (13)CO(2) atmosphere in natural soil. DNA from the rhizospheric soil was separated by density gradient centrifugation. Bacterial (Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria and Acidobacteria), Archaea and fungal community structures were analysed by DGGE fingerprints of amplified 16S and 18S rRNA gene sequences. Specific populations were characterized by sequencing DGGE fragments. Roots of the transgenic plant line presented an altered profile of glucosinolates and other minor additional modifications. These modifications significantly influenced microbial community on roots and active populations in the rhizosphere. Alphaproteobacteria, particularly Rhizobiaceae, and fungal communities were mainly impacted by these Brassicaceous metabolites, in both structure and composition. Our results showed that even a minor modification in plant root could have important repercussions for soil microbial communities.

  20. Cell-specific vacuolar calcium storage mediated by CAX1 regulates apoplastic calcium concentration, gas exchange, and plant productivity in Arabidopsis.

    Science.gov (United States)

    Conn, Simon J; Gilliham, Matthew; Athman, Asmini; Schreiber, Andreas W; Baumann, Ute; Moller, Isabel; Cheng, Ning-Hui; Stancombe, Matthew A; Hirschi, Kendal D; Webb, Alex A R; Burton, Rachel; Kaiser, Brent N; Tyerman, Stephen D; Leigh, Roger A

    2011-01-01

    The physiological role and mechanism of nutrient storage within vacuoles of specific cell types is poorly understood. Transcript profiles from Arabidopsis thaliana leaf cells differing in calcium concentration ([Ca], epidermis 60 mM) were compared using a microarray screen and single-cell quantitative PCR. Three tonoplast-localized Ca(2+) transporters, CAX1 (Ca(2+)/H(+)-antiporter), ACA4, and ACA11 (Ca(2+)-ATPases), were identified as preferentially expressed in Ca-rich mesophyll. Analysis of respective loss-of-function mutants demonstrated that only a mutant that lacked expression of both CAX1 and CAX3, a gene ectopically expressed in leaves upon knockout of CAX1, had reduced mesophyll [Ca]. Reduced capacity for mesophyll Ca accumulation resulted in reduced cell wall extensibility, stomatal aperture, transpiration, CO(2) assimilation, and leaf growth rate; increased transcript abundance of other Ca(2+) transporter genes; altered expression of cell wall-modifying proteins, including members of the pectinmethylesterase, expansin, cellulose synthase, and polygalacturonase families; and higher pectin concentrations and thicker cell walls. We demonstrate that these phenotypes result from altered apoplastic free [Ca(2+)], which is threefold greater in cax1/cax3 than in wild-type plants. We establish CAX1 as a key regulator of apoplastic [Ca(2+)] through compartmentation into mesophyll vacuoles, a mechanism essential for optimal plant function and productivity.

  1. Xrcc1-dependent and Ku-dependent DNA double-strand break repair kinetics in Arabidopsis plants.

    Science.gov (United States)

    Charbonnel, Cyril; Gallego, Maria E; White, Charles I

    2010-10-01

    Double-strand breakage (DSB) of DNA involves loss of information on the two strands of the DNA fibre and thus cannot be repaired by simple copying of the complementary strand which is possible with single-strand DNA damage. Homologous recombination (HR) can precisely repair DSB using another copy of the genome as template and non-homologous recombination (NHR) permits repair of DSB with little or no dependence on DNA sequence homology. In addition to the well-characterised Ku-dependent non-homologous end-joining (NHEJ) pathway, much recent attention has been focused on Ku-independent NHR. The complex interrelationships and regulation of NHR pathways remain poorly understood, even more so in the case of plants, and we present here an analysis of Ku-dependent and Ku-independent repair of DSB in Arabidopsis thaliana. We have characterised an Arabidopsis xrcc1 mutant and developed quantitative analysis of the kinetics of appearance and loss of γ-H2AX foci as a tool to measure DSB repair in dividing root tip cells of γ-irradiated plants in vivo. This approach has permitted determination of DSB repair kinetics in planta following a short pulse of γ-irradiation, establishing the existence of a Ku-independent, Xrcc1-dependent DSB repair pathway. Furthermore, our data show a role for Ku80 during the first minutes post-irradiation and that Xrcc1 also plays such a role, but only in the absence of Ku. The importance of Xrcc1 is, however, clearly visible at later times in the presence of Ku, showing that alternative end-joining plays an important role in DSB repair even in the presence of active NHEJ. © 2010 The Authors. Journal compilation © 2010 Blackwell Publishing Ltd.

  2. Wheat chloroplast targeted sHSP26 promoter confers heat and abiotic stress inducible expression in transgenic Arabidopsis Plants.

    Directory of Open Access Journals (Sweden)

    Neetika Khurana

    Full Text Available The small heat shock proteins (sHSPs have been found to play a critical role in physiological stress conditions in protecting proteins from irreversible aggregation. To characterize the hloroplast targeted sHSP26 promoter in detail, deletion analysis of the promoter is carried out and analysed via transgenics in Arabidopsis. In the present study, complete assessment of the importance of CCAAT-box elements along with Heat shock elements (HSEs in the promoter of sHSP26 was performed. Moreover, the importance of 5' untranslated region (UTR has also been established in the promoter via Arabidopsis transgenics. An intense GUS expression was observed after heat stress in the transgenics harbouring a full-length promoter, confirming the heat-stress inducibility of the promoter. Transgenic plants without UTR showed reduced GUS expression when compared to transgenic plants with UTR as was confirmed at the RNA and protein levels by qRT-PCR and GUS histochemical assays, thus suggesting the possible involvement of some regulatory elements present in the UTR in heat-stress inducibility of the promoter. Promoter activity was also checked under different abiotic stresses and revealed differential expression in different deletion constructs. Promoter analysis based on histochemical assay, real-time qPCR and fluorimetric analysis revealed that HSEs alone could not transcribe GUS gene significantly in sHSP26 promoter and CCAAT box elements contribute synergistically to the transcription. Our results also provide insight into the importance of 5`UTR of sHsp26 promoter thus emphasizing the probable role of imperfect CCAAT-box element or some novel cis-element with respect to heat stress.

  3. Alleviation of salt stress by enterobacter sp. EJ01 in tomato and Arabidopsis is accompanied by up-regulation of conserved salinity responsive factors in plants.

    Science.gov (United States)

    Kim, Kangmin; Jang, Ye-Jin; Lee, Sang-Myeong; Oh, Byung-Taek; Chae, Jong-Chan; Lee, Kui-Jae

    2014-02-01

    Microbiota in the niches of the rhizosphere zones can affect plant growth and responses to environmental stress conditions via mutualistic interactions with host plants. Specifically, some beneficial bacteria, collectively referred to as Plant Growth Promoting Rhizobacteria (PGPRs), increase plant biomass and innate immunity potential. Here, we report that Enterobacter sp. EJ01, a bacterium isolated from sea china pink (Dianthus japonicus thunb) in reclaimed land of Gyehwa-do in Korea, improved the vegetative growth and alleviated salt stress in tomato and Arabidopsis. EJ01 was capable of producing 1-aminocy-clopropane-1-carboxylate (ACC) deaminase and also exhibited indole-3-acetic acid (IAA) production. The isolate EJ01 conferred increases in fresh weight, dry weight, and plant height of tomato and Arabidopsis under both normal and high salinity conditions. At the molecular level, short-term treatment with EJ01 increased the expression of salt stress responsive genes such as DREB2b, RD29A, RD29B, and RAB18 in Arabidopsis. The expression of proline biosynthetic genes (i.e. P5CS1 and P5CS2) and of genes related to priming processes (i.e. MPK3 and MPK6) were also up-regulated. In addition, reactive oxygen species scavenging activities were enhanced in tomatoes treated with EJ01 in stressed conditions. GFP-tagged EJ01 displayed colonization in the rhizosphere and endosphere in the roots of Arabidopsis. In conclusion, the newly isolated Enterobacter sp. EJ01 is a likely PGPR and alleviates salt stress in host plants through multiple mechanisms, including the rapid up-regulation of conserved plant salt stress responsive signaling pathways.

  4. Alleviation of Salt Stress by Enterobacter sp. EJ01 in Tomato and Arabidopsis Is Accompanied by Up-Regulation of Conserved Salinity Responsive Factors in Plants

    Science.gov (United States)

    Kim, Kangmin; Jang, Ye-Jin; Lee, Sang-Myeong; Oh, Byung-Taek; Chae, Jong-Chan; Lee, Kui-Jae

    2014-01-01

    Microbiota in the niches of the rhizosphere zones can affect plant growth and responses to environmental stress conditions via mutualistic interactions with host plants. Specifically, some beneficial bacteria, collectively referred to as Plant Growth Promoting Rhizobacteria (PGPRs), increase plant biomass and innate immunity potential. Here, we report that Enterobacter sp. EJ01, a bacterium isolated from sea china pink (Dianthus japonicus thunb) in reclaimed land of Gyehwa-do in Korea, improved the vegetative growth and alleviated salt stress in tomato and Arabidopsis. EJ01 was capable of producing 1-aminocy-clopropane-1-carboxylate (ACC) deaminase and also exhibited indole-3-acetic acid (IAA) production. The isolate EJ01 conferred increases in fresh weight, dry weight, and plant height of tomato and Arabidopsis under both normal and high salinity conditions. At the molecular level, short-term treatment with EJ01 increased the expression of salt stress responsive genes such as DREB2b, RD29A, RD29B, and RAB18 in Arabidopsis. The expression of proline biosynthetic genes (i.e. P5CS1 and P5CS2) and of genes related to priming processes (i.e. MPK3 and MPK6) were also up-regulated. In addition, reactive oxygen species scavenging activities were enhanced in tomatoes treated with EJ01 in stressed conditions. GFP-tagged EJ01 displayed colonization in the rhizosphere and endosphere in the roots of Arabidopsis. In conclusion, the newly isolated Enterobacter sp. EJ01 is a likely PGPR and alleviates salt stress in host plants through multiple mechanisms, including the rapid up-regulation of conserved plant salt stress responsive signaling pathways. PMID:24598995

  5. DNA repair in mutagen-injured higher plants

    International Nuclear Information System (INIS)

    Veleminsky, J.; Gichner, T.

    1978-01-01

    Data are summarized proving the occurrence of photoreactivation of UV-induced pyrimidine dimers in cells of Nicotiana tabucum, Gingko and carrot, the excision of dimers in cells of Nicotiana tabacum, Gingko and carrot, the excision of dimers in protoplasts of carrot and in embryos of Lathyrus sativus, and the repair of DNA single-strand breaks induced in carrot protoplasts and barley embryonic cells by ionizing radiation. In irradiated barley embryos the unscheduled DNA synthesis and higher accessibility of induced primers to DNA polymerase I of E. coli were observed preferentially in G 1 cells with diffused chromatin. These reactions were inhibited by caffeine and EDTA. Unscheduled DNA synthesis was also observed in synchronized irradiated root cuttings of Vicia faba and in barley embryos treated with 4-nitroquinoline oxide, the latter being inhibited by caffeine and hydroxyurea. Repair synthesis was also established in barley embryos treated with mutagenic N-methyl-N-nitrosourea under conditions that postponed the onset of germination after the treatment. The same conditions enhanced the repair of DNA single-strand breaks induced by this mutagen and several other monofunctional alkylating compounds. From tissues of barley and of Phaseolus multiflorus, endonucleases for apurinic sites were isolated and characterized. Some of them are located in chromatin, others in chloroplasts. The relation between DNA repair and genetic effects of mutagens in higher plants is also discussed. (Auth.)

  6. Photosystem II repair and plant immunity: Lessons learned from Arabidopsis mutant lacking the THYLAKOID LUMEN PROTEIN 18.3

    Directory of Open Access Journals (Sweden)

    Sari eJärvi

    2016-03-01

    Full Text Available Chloroplasts play an important role in the cellular sensing of abiotic and biotic stress. Signals originating from photosynthetic light reactions, in the form of redox and pH changes, accumulation of reactive oxygen and electrophile species or stromal metabolites are of key importance in chloroplast retrograde signaling. These signals initiate plant acclimation responses to both abiotic and biotic stresses. To reveal the molecular responses activated by rapid fluctuations in growth light intensity, gene expression analysis was performed with Arabidopsis thaliana wild type and the tlp18.3 mutant plants, the latter showing a stunted growth phenotype under fluctuating light conditions (Biochem. J, 406, 415-425. Expression pattern of genes encoding components of the photosynthetic electron transfer chain did not differ between fluctuating and constant light conditions, neither in wild type nor in tlp18.3 plants, and the composition of the thylakoid membrane protein complexes likewise remained unchanged. Nevertheless, the fluctuating light conditions repressed in wild-type plants a broad spectrum of genes involved in immune responses, which likely resulted from shade-avoidance responses and their intermixing with hormonal signaling. On the contrary, in the tlp18.3 mutant plants there was an imperfect repression of defense-related transcripts upon growth under fluctuating light, possibly by signals originating from minor malfunction of the photosystem II (PSII repair cycle, which directly or indirectly modulated the transcript abundances of genes related to light perception via phytochromes. Consequently, a strong allocation of resources to defense reactions in the tlp18.3 mutant plants presumably results in the stunted growth phenotype under fluctuating light.

  7. Genetic dissection of the Arabidopsis spaceflight transcriptome: Are some responses dispensable for the physiological adaptation of plants to spaceflight?

    Directory of Open Access Journals (Sweden)

    Anna-Lisa Paul

    Full Text Available Experimentation on the International Space Station has reached the stage where repeated and nuanced transcriptome studies are beginning to illuminate the structural and metabolic differences between plants grown in space compared to plants on the Earth. Genes that are important in establishing the spaceflight responses are being identified, their roles in spaceflight physiological adaptation are increasingly understood, and the fact that different genotypes adapt differently is recognized. However, the basic question of whether these spaceflight responses are actually required for survival has yet to be posed, and the fundamental notion that spaceflight responses may be non-adaptive has yet to be explored. Therefore the experiments presented here were designed to ask if portions of the plant spaceflight response can be genetically removed without causing loss of spaceflight survival and without causing increased stress responses. The CARA experiment compared the spaceflight transcriptome responses in the root tips of two Arabidopsis ecotypes, Col-0 and WS, as well as that of a PhyD mutant of Col-0. When grown with the ambient light of the ISS, phyD plants displayed a significantly reduced spaceflight transcriptome response compared to Col-0, suggesting that altering the activity of a single gene can actually improve spaceflight adaptation by reducing the transcriptome cost of physiological adaptation. The WS genotype showed an even simpler spaceflight transcriptome response in the ambient light of the ISS, more broadly indicating that the plant genotype can be manipulated to reduce the cost of spaceflight adaptation, as measured by transcriptional response. These differential genotypic responses suggest that genetic manipulation could further reduce, or perhaps eliminate the metabolic cost of spaceflight adaptation. When plants were germinated and then left in the dark on the ISS, the WS genotype actually mounted a larger transcriptome response

  8. Role of stress-related hormones in plant defence during early infection of the cyst nematode Heterodera schachtii in Arabidopsis

    Science.gov (United States)

    Kammerhofer, Nina; Radakovic, Zoran; Regis, Jully M A; Dobrev, Petre; Vankova, Radomira; Grundler, Florian M W; Siddique, Shahid; Hofmann, Julia; Wieczorek, Krzysztof

    2015-01-01

    Heterodera schachtii, a plant-parasitic cyst nematode, invades host roots and induces a specific syncytial feeding structure, from which it withdraws all required nutrients, causing severe yield losses. The system H. schachtii–Arabidopsis is an excellent research model for investigating plant defence mechanisms. Such responses are suppressed in well-established syncytia, whereas they are induced during early parasitism. However, the mechanisms by which the defence responses are modulated and the role of phytohormones are largely unknown. The aim of this study was to elucidate the role of hormone-based defence responses at the onset of nematode infection. First, concentrations of main phytohormones were quantified and the expression of several hormone-related genes was analysed using quantitative real-time (qRT)-PCR or GeneChip. Further, the effects of individual hormones were evaluated via nematode attraction and infection assays using plants with altered endogenous hormone concentrations. Our results suggest a pivotal and positive role for ethylene during nematode attraction, whereas jasmonic acid triggers early defence responses against H. schachtii. Salicylic acid seems to be a negative regulator during later syncytium and female development. We conclude that nematodes are able to impose specific changes in hormone pools, thus modulating hormone-based defence and signal transduction in strict dependence on their parasitism stage. PMID:25825039

  9. The Arabidopsis eukaryotic initiation factor (iso)4E is dispensable for plant growth but required for susceptibility to potyviruses.

    Science.gov (United States)

    Duprat, Anne; Caranta, Carole; Revers, Frédéric; Menand, Benoît; Browning, Karen S; Robaglia, Christophe

    2002-12-01

    An Arabidopsis thaliana line bearing a transposon insertion in the gene coding for the isozyme form of the plant-specific cap-binding protein, eukaryotic initiation factor (iso) 4E (eIF (iso) 4E), has been isolated. This mutant line completely lacks both eIF(iso)4E mRNA and protein, but was found to have a phenotype and fertility indistinguishable from wild-type plants under standard laboratory conditions. In contrast, the amount of the related eIF4E protein was found to increase in seedling extracts. Furthermore, polysome analysis shows that the mRNA encoding eIF4E was being translated at increased levels. Given the known interaction between cap-binding proteins and potyviral genome-linked proteins (VPg), this plant line was challenged with two potyviruses, Turnip mosaic virus (TuMV) and Lettuce mosaic virus (LMV) and was found resistant to both, but not to the Nepovirus, Tomato black ring virus (TBRV) and the Cucumovirus, Cucumber mosaic virus (CMV). Together with previous data showing that the VPg-eIF4E interaction is necessary for virus infectivity and upregulates genome amplification, this shows that the eIF4E proteins are specifically recruited for the replication cycle of potyviruses.

  10. Impact of SO(2) on Arabidopsis thaliana transcriptome in wildtype and sulfite oxidase knockout plants analyzed by RNA deep sequencing.

    Science.gov (United States)

    Hamisch, Domenica; Randewig, Dörte; Schliesky, Simon; Bräutigam, Andrea; Weber, Andreas P M; Geffers, Robert; Herschbach, Cornelia; Rennenberg, Heinz; Mendel, Ralf R; Hänsch, Robert

    2012-12-01

    High concentrations of sulfur dioxide (SO(2) ) as an air pollutant, and its derivative sulfite, cause abiotic stress that can lead to cell death. It is currently unknown to what extent plant fumigation triggers specific transcriptional responses. To address this question, and to test the hypothesis that sulfite oxidase (SO) is acting in SO(2) detoxification, we compared Arabidopsis wildtype (WT) and SO knockout lines (SO-KO) facing the impact of 600 nl l(-1) SO(2) , using RNAseq to quantify absolute transcript abundances. These transcriptome data were correlated to sulfur metabolism-related enzyme activities and metabolites obtained from identical samples in a previous study. SO-KO plants exhibited remarkable and broad regulative responses at the mRNA level, especially in transcripts related to sulfur metabolism enzymes, but also in those related to stress response and senescence. Focusing on SO regulation, no alterations were detectable in the WT, whereas in SO-KO plants we found up-regulation of two splice variants of the SO gene, although this gene is not functional in this line. Our data provide evidence for the highly specific coregulation between SO and sulfur-related enzymes like APS reductase, and suggest two novel candidates for involvement in SO(2) detoxification: an apoplastic peroxidase, and defensins as putative cysteine mass storages. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

  11. Identification of the arabidopsis RAM/MOR signalling network: adding new regulatory players in plant stem cell maintenance and cell polarization

    Science.gov (United States)

    Zermiani, Monica; Begheldo, Maura; Nonis, Alessandro; Palme, Klaus; Mizzi, Luca; Morandini, Piero; Nonis, Alberto; Ruperti, Benedetto

    2015-01-01

    Background and Aims The RAM/MOR signalling network of eukaryotes is a conserved regulatory module involved in co-ordination of stem cell maintenance, cell differentiation and polarity establishment. To date, no such signalling network has been identified in plants. Methods Genes encoding the bona fide core components of the RAM/MOR pathway were identified in Arabidopsis thaliana (arabidopsis) by sequence similarity searches conducted with the known components from other species. The transcriptional network(s) of the arabidopsis RAM/MOR signalling pathway were identified by running in-depth in silico analyses for genes co-regulated with the core components. In situ hybridization was used to confirm tissue-specific expression of selected RAM/MOR genes. Key Results Co-expression data suggested that the arabidopsis RAM/MOR pathway may include genes involved in floral transition, by co-operating with chromatin remodelling and mRNA processing/post-transcriptional gene silencing factors, and genes involved in the regulation of pollen tube polar growth. The RAM/MOR pathway may act upstream of the ROP1 machinery, affecting pollen tube polar growth, based on the co-expression of its components with ROP-GEFs. In silico tissue-specific co-expression data and in situ hybridization experiments suggest that different components of the arabidopsis RAM/MOR are expressed in the shoot apical meristem and inflorescence meristem and may be involved in the fine-tuning of stem cell maintenance and cell differentiation. Conclusions The arabidopsis RAM/MOR pathway may be part of the signalling cascade that converges in pollen tube polarized growth and in fine-tuning stem cell maintenance, differentiation and organ polarity. PMID:26078466

  12. Higher plants as biomonitors of radionuclides in urban air

    International Nuclear Information System (INIS)

    Ajtic, J.; Todorovic, D.; Popovic, D.; Nikolic, J.

    2011-01-01

    Two deciduous tree genera, linden (Tilia tomentosa L. and Tilia cordata Mill.) and chestnut (Aesculus hippocastanum L.), are analysed as biomonitors of 210 Pb and 7 Be in air. In a multi year study (2002 - 2009), conducted in three city parks in Belgrade, the content of 210 Pb and 7 Be in samples of leaves of linden and chestnut trees, and aerosols was determined on an HPGe detector by standard gamma spectrometry. The differences seen in the radionuclides' activities across the measurement sites and between the tree genera are not significant, suggesting that the micro climate, level of air pollution and physiological characteristics of the trees have a negligible effect on the radionuclides' activities in leaves. Linear Pearson's correlation coefficients are used to correlate the 210 Pb and 7 Be activities in aerosols and in leaves. The results show that linden could be used as a 210 Pb biomonitor which provides information on the recent history of exposure. No large positive correlation is found for the 7 Be activities in leaves and aerosols, indicating that higher plants are not a suitable biomonitor for this radionuclide. [sr

  13. Plant design aspects of catalytic biosyngas conversion to higher alcohols

    International Nuclear Information System (INIS)

    Atsonios, K.; Christodoulou, Ch.; Koytsoumpa, E.-I.; Panopoulos, K.D.; Kakaras, Em.

    2013-01-01

    Although biomethanol production has attracted most of the attention in the past years, there is a current trend for the synthesis of higher alcohols (i.e. ethanol, plus C 3 –C 4 ) from biomass gasification. These compounds could be used directly as fuel or fuel additives for octane or cetane number enhancement. These also serve as important intermediates for the chemical industry. In this paper a comparison is performed between the different process configurations a higher alcohols production plant from biomass gasification can take. These options are modelled in Aspenplus™; all steps and important unit operations are presented with the aim to correctly evaluate the peripheral energy requirements and conclude with the overall thermodynamic limitations of the processes. The differentiation between black liquor and solid biomass gasification, the type of catalyst employed, and the effect of the recycling scheme adopted for the reutilization of unreacted syngas are evaluated. The design has to cope with the limited yields and poor selectivity of catalysts developed so far. The gas cleaning is different depending on the different requirements of the catalysts as far as H 2 S purity. The process modelling results reveal that the hydrogenation of CO to higher alcohols is favoured by high pressure, temperature around 325 °C and high reactor residence times. A biorefinery using modified Fisher–Tropsch (FT) catalysts (MoS 2 ) prevail over modified MeOH catalyst (Cu–Zn based) for HA production. The efficiency of HA production in HHV terms can reach up to 25%. -- Graphical abstract: Process flow diagrams of different biorefinery systems derived from a) woody biomass and b) black liquor. Highlights: ► An integrated gasification/gas-cleaning/synthesis system was modelled in Aspenplus. ► HA production from wood and black liquor gasification is compared. ► Modified FT catalysts prevail over modified methanol catalyst for HA production. ► HA productivity is

  14. Arabidopsis and Brachypodium distachyon Transgenic Plants Expressing Aspergillus nidulans Acetylesterases Have Decreased Degree of Polysaccharide Acetylation and Increased Resistance to Pathogens1[C][W][OA

    Science.gov (United States)

    Pogorelko, Gennady; Lionetti, Vincenzo; Fursova, Oksana; Sundaram, Raman M.; Qi, Mingsheng; Whitham, Steven A.; Bogdanove, Adam J.; Bellincampi, Daniela; Zabotina, Olga A.

    2013-01-01

    The plant cell wall has many significant structural and physiological roles, but the contributions of the various components to these roles remain unclear. Modification of cell wall properties can affect key agronomic traits such as disease resistance and plant growth. The plant cell wall is composed of diverse polysaccharides often decorated with methyl, acetyl, and feruloyl groups linked to the sugar subunits. In this study, we examined the effect of perturbing cell wall acetylation by making transgenic Arabidopsis (Arabidopsis thaliana) and Brachypodium (Brachypodium distachyon) plants expressing hemicellulose- and pectin-specific fungal acetylesterases. All transgenic plants carried highly expressed active Aspergillus nidulans acetylesterases localized to the apoplast and had significant reduction of cell wall acetylation compared with wild-type plants. Partial deacetylation of polysaccharides caused compensatory up-regulation of three known acetyltransferases and increased polysaccharide accessibility to glycosyl hydrolases. Transgenic plants showed increased resistance to the fungal pathogens Botrytis cinerea and Bipolaris sorokiniana but not to the bacterial pathogens Pseudomonas syringae and Xanthomonas oryzae. These results demonstrate a role, in both monocot and dicot plants, of hemicellulose and pectin acetylation in plant defense against fungal pathogens. PMID:23463782

  15. Structure of the higher plant light harvesting complex I: in vivo characterization and structural interdependence of the Lhca proteins.

    Science.gov (United States)

    Klimmek, Frank; Ganeteg, Ulrika; Ihalainen, Janne A; van Roon, Henny; Jensen, Poul E; Scheller, Henrik V; Dekker, Jan P; Jansson, Stefan

    2005-03-01

    We have investigated the structure of the higher plant light harvesting complex of photosystem I (LHCI) by analyzing PSI-LHCI particles isolated from a set of Arabidopsis plant lines, each lacking a specific Lhca (Lhca1-4) polypeptide. Functional antenna size measurements support the recent finding that there are four Lhca proteins per PSI in the crystal structure [Ben-Shem, A., Frolow, F., and Nelson, N. (2003) Nature 426, 630-635]. According to HPLC analyses the number of pigment molecules bound within the LHCI is higher than expected from reconstitution studies or analyses of isolated native LHCI. Comparison of the spectra of the particles from the different lines reveals chlorophyll absorption bands peaking at 696, 688, 665, and 655 nm that are not present in isolated PSI or LHCI. These bands presumably originate from "gap" or "linker" pigments that are cooperatively coordinated by the Lhca and/or PSI proteins, which we have tentatively localized in the PSI-LHCI complex.

  16. Absorption and conversion of nitrogen dioxide by higher plants

    International Nuclear Information System (INIS)

    Durmishidze, S.V.; Nutsubidze, N.N.

    1976-01-01

    An investigation was performed to study the ability of plants to absorb and metabolize NO 2 , as well as to reduce and incorporate nitrogen into amino acid molecules. Experiments on the absorption of NO 2 labeled with 15 N were conducted in special chambers, both on whole plants and on fresh-cut branches. NO 2 was used in various concentrations from 0.01 to 5% of the volume. The exposure of the experiments ranged from 5 min to 7 days, involving more than 60 species of perennial and annual plants. The processes of assimilation and conversion of NO 2 from the air to amino acids by plants are related. The conversion scheme showed close association with physiological state of the plant and with external factors of its vital activity. It is conceivable that plants that intensively absorb and convert oxides of nitrogen and give a large biomass can be used for the purification air

  17. Characterization of the vacuolar H sup + -ATPase of higher plants

    Energy Technology Data Exchange (ETDEWEB)

    Manolson, M F

    1988-01-01

    The tonoplast H{sup +}-ATPase of Beta vulgaris L. was partially purified by Triton X-100 solubilization and Sepharose 4B chromatography resulting in the enrichment of two polypeptides. Kinetic analysis of ({alpha}-{sup 32}P) BzATP labeling identified the 57 kDa polypeptide as a nucleotide-binding subunit with a possible regulatory function. In addition, ({sup 14}C) DCCD-labeling identified a 16 kDa polypeptide as a putative transmembrane proton channel. It is concluded that the tonoplast H{sup +}-ATPase is a multimer composed of at least three polypeptides. Anti-57 and anti-67 kDa sera reacted with polypeptides of the corresponding size in bovine chromaffin granules, bovine clathrin-coated vesicles, and yeast vacuolar membranes, suggesting common structural features and common ancestry for endomembrane H{sup +}-ATPase of different organelles and different phyla. Anti-57 serum was used to isolate a cDNA encoding the corresponding subunit from Arabidopsis. Protein sequence analysis revealed homologies between endomembrane, F{sub 0}F{sub 1} and archaebacterial ATPases, suggesting that these different classes of ATPases have evolved from a common ancestor.

  18. The Arabidopsis spaceflight transcriptome: a comparison of whole plants to discrete root hypocotyl and shoot responses to the orbital environment

    Data.gov (United States)

    National Aeronautics and Space Administration — Arabidopsis thaliana was evaluated for its response to the spaceflight environment in three replicated experiments on the International Space Station. Two approaches...

  19. Towards annotating the plant epigenome: the Arabidopsis thaliana small RNA locus map.

    Science.gov (United States)

    Hardcastle, Thomas J; Müller, Sebastian Y; Baulcombe, David C

    2018-04-20

    Based on 98 public and internal small RNA high throughput sequencing libraries, we mapped small RNAs to the genome of the model organism Arabidopsis thaliana and defined loci based on their expression using an empirical Bayesian approach. The resulting loci were subsequently classified based on their genetic and epigenetic context as well as their expression properties. We present the results of this classification, which broadly conforms to previously reported divisions between transcriptional and post-transcriptional gene silencing small RNAs, and to PolIV and PolV dependencies. However, we are able to demonstrate the existence of further subdivisions in the small RNA population of functional significance. Moreover, we present a framework for similar analyses of small RNA populations in all species.

  20. The molecular basis of disease resistance in higher plants

    African Journals Online (AJOL)

    xxxxxx

    Therefore, manipulating a single transcription factor could have the same effect as manipulating a set of specific genes within the plant. As highlighted above, transgenic plants allow the targeted ... including molecular techniques and genetics will provide insights into pathogen-defense mechanism and subsequent disease ...

  1. The plant cuticle is required for osmotic stress regulation of abscisic acid biosynthesis and osmotic stress tolerance in Arabidopsis

    KAUST Repository

    Wang, Zhenyu

    2011-05-01

    Osmotic stress activates the biosynthesis of abscisic acid (ABA). One major step in ABA biosynthesis is the carotenoid cleavage catalyzed by a 9-cis epoxycarotenoid dioxygenase (NCED). To understand the mechanism for osmotic stress activation of ABA biosynthesis, we screened for Arabidopsis thaliana mutants that failed to induce the NCED3 genee xpression in response to osmotic stress treatments. The ced1 (for 9-cis epoxycarotenoid dioxy genase defective 1) mutant isolated in this study showed markedly reduced expression of NCED3 in response to osmotic stress (polyethylene glycol)treatments compared with the wild type. Other ABA biosynthesis genes are also greatly reduced in ced1 under osmotic stress. ced1 mutant plants are very sensitive to even mild osmotic stress. Map-based cloning revealed unexpectedly thatCED1 encodes a putative a/b hydrolase domain-containing protein and is allelic to the BODYGUARD gene that was recently shown to be essential for cuticle biogenesis. Further studies discovered that other cut in biosynthesis mutants are also impaired in osmotic stress induction of ABA biosynthesis genes and are sensitive to osmotic stress. Our work demonstrates that the cuticle functions not merely as a physical barrier to minimize water loss but also mediates osmotic stress signaling and tolerance by regulating ABA biosynthesis and signaling. © 2011 American Society of Plant Biologists. All rights reserved.

  2. Study on transfer and effects of radioactive materials into plants. Study on transfer and effects of radioactive materials into arabidopsis thaliana (L.) Heynh

    International Nuclear Information System (INIS)

    Tsurudome, Koji; Tokizawa, Takayuki

    2000-05-01

    The method of evaluating genetic effects and the measuring method of radiation dose distribution were studied. DNA was extracted from the arabidopsis thaliana (L.) Heynh (A. thaliana) grow in mine soil. The sequence of chalcone synthase gene and cinnamate-4-hydroxylase gene were analysed. No gene mutation was observed. Radiation dose distribution was studied by using x-ray films and imaging plates. No biologically concentrated region was observed in plants. (A. Yamamoto)

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

    OpenAIRE

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

    2011-01-01

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

  4. Evolutionary Dynamics of Microsatellite Distribution in Plants: Insight from the Comparison of Sequenced Brassica, Arabidopsis and Other Angiosperm Species

    Science.gov (United States)

    Shi, Jiaqin; Huang, Shunmou; Fu, Donghui; Yu, Jinyin; Wang, Xinfa; Hua, Wei; Liu, Shengyi; Liu, Guihua; Wang, Hanzhong

    2013-01-01

    Despite their ubiquity and functional importance, microsatellites have been largely ignored in comparative genomics, mostly due to the lack of genomic information. In the current study, microsatellite distribution was characterized and compared in the whole genomes and both the coding and non-coding DNA sequences of the sequenced Brassica, Arabidopsis and other angiosperm species to investigate their evolutionary dynamics in plants. The variation in the microsatellite frequencies of these angiosperm species was much smaller than those for their microsatellite numbers and genome sizes, suggesting that microsatellite frequency may be relatively stable in plants. The microsatellite frequencies of these angiosperm species were significantly negatively correlated with both their genome sizes and transposable elements contents. The pattern of microsatellite distribution may differ according to the different genomic regions (such as coding and non-coding sequences). The observed differences in many important microsatellite characteristics (especially the distribution with respect to motif length, type and repeat number) of these angiosperm species were generally accordant with their phylogenetic distance, which suggested that the evolutionary dynamics of microsatellite distribution may be generally consistent with plant divergence/evolution. Importantly, by comparing these microsatellite characteristics (especially the distribution with respect to motif type) the angiosperm species (aside from a few species) all clustered into two obviously different groups that were largely represented by monocots and dicots, suggesting a complex and generally dichotomous evolutionary pattern of microsatellite distribution in angiosperms. Polyploidy may lead to a slight increase in microsatellite frequency in the coding sequences and a significant decrease in microsatellite frequency in the whole genome/non-coding sequences, but have little effect on the microsatellite distribution with

  5. Multiple abiotic stress tolerance of the transformants yeast cells and the transgenic Arabidopsis plants expressing a novel durum wheat catalase.

    Science.gov (United States)

    Feki, Kaouthar; Kamoun, Yosra; Ben Mahmoud, Rihem; Farhat-Khemakhem, Ameny; Gargouri, Ali; Brini, Faiçal

    2015-12-01

    Catalases are reactive oxygen species scavenging enzymes involved in response to abiotic and biotic stresses. In this study, we described the isolation and functional characterization of a novel catalase from durum wheat, designed TdCAT1. Molecular Phylogeny analyses showed that wheat TdCAT1 exhibited high amino acids sequence identity to other plant catalases. Sequence homology analysis showed that TdCAT1 protein contained the putative calmodulin binding domain and a putative conserved internal peroxisomal targeting signal PTS1 motif around its C-terminus. Predicted three-dimensional structural model revealed the presence of four putative distinct structural regions which are the N-terminal arm, the β-barrel, the wrapping and the α-helical domains. TdCAT1 protein had the heme pocket that was composed by five essential residues. TdCAT1 gene expression analysis showed that this gene was induced by various abiotic stresses in durum wheat. The expression of TdCAT1 in yeast cells and Arabidopsis plants conferred tolerance to several abiotic stresses. Compared with the non-transformed plants, the transgenic lines maintained their growth and accumulated more proline under stress treatments. Furthermore, the amount of H2O2 was lower in transgenic lines, which was due to the high CAT and POD activities. Taken together, these data provide the evidence for the involvement of durum wheat catalase TdCAT1 in tolerance to multiple abiotic stresses in crop plants. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  6. Evolutionary dynamics of microsatellite distribution in plants: insight from the comparison of sequenced brassica, Arabidopsis and other angiosperm species.

    Directory of Open Access Journals (Sweden)

    Jiaqin Shi

    Full Text Available Despite their ubiquity and functional importance, microsatellites have been largely ignored in comparative genomics, mostly due to the lack of genomic information. In the current study, microsatellite distribution was characterized and compared in the whole genomes and both the coding and non-coding DNA sequences of the sequenced Brassica, Arabidopsis and other angiosperm species to investigate their evolutionary dynamics in plants. The variation in the microsatellite frequencies of these angiosperm species was much smaller than those for their microsatellite numbers and genome sizes, suggesting that microsatellite frequency may be relatively stable in plants. The microsatellite frequencies of these angiosperm species were significantly negatively correlated with both their genome sizes and transposable elements contents. The pattern of microsatellite distribution may differ according to the different genomic regions (such as coding and non-coding sequences. The observed differences in many important microsatellite characteristics (especially the distribution with respect to motif length, type and repeat number of these angiosperm species were generally accordant with their phylogenetic distance, which suggested that the evolutionary dynamics of microsatellite distribution may be generally consistent with plant divergence/evolution. Importantly, by comparing these microsatellite characteristics (especially the distribution with respect to motif type the angiosperm species (aside from a few species all clustered into two obviously different groups that were largely represented by monocots and dicots, suggesting a complex and generally dichotomous evolutionary pattern of microsatellite distribution in angiosperms. Polyploidy may lead to a slight increase in microsatellite frequency in the coding sequences and a significant decrease in microsatellite frequency in the whole genome/non-coding sequences, but have little effect on the microsatellite

  7. Engineered silver nanoparticles are sensed at the plasma membrane and dramatically modify the physiology of Arabidopsis thaliana plants.

    Science.gov (United States)

    Sosan, Arifa; Svistunenko, Dimitri; Straltsova, Darya; Tsiurkina, Katsiaryna; Smolich, Igor; Lawson, Tracy; Subramaniam, Sunitha; Golovko, Vladimir; Anderson, David; Sokolik, Anatoliy; Colbeck, Ian; Demidchik, Vadim

    2016-01-01

    Silver nanoparticles (Ag NPs) are the world's most important nanomaterial and nanotoxicant. The aim of this study was to determine the early stages of interactions between Ag NPs and plant cells, and to investigate their physiological roles. We have shown that the addition of Ag NPs to cultivation medium, at levels above 300 mg L(-1) , inhibited Arabidopsis thaliana root elongation and leaf expansion. This also resulted in decreased photosynthetic efficiency and the extreme accumulation of Ag in tissues. Acute application of Ag NPs induced a transient elevation of [Ca(2+) ]cyt and the accumulation of reactive oxygen species (ROS; partially generated by NADPH oxidase). Whole-cell patch-clamp measurements on root cell protoplasts demonstrated that Ag NPs slightly inhibited plasma membrane K(+) efflux and Ca(2+) influx currents, or caused membrane breakdown; however, in excised outside-out patches, Ag NPs activated Gd(3+) -sensitive Ca(2+) influx channels with unitary conductance of approximately 56 pS. Bulk particles did not modify the plasma membrane currents. Tests with electron paramagnetic resonance spectroscopy showed that Ag NPs were not able to catalyse hydroxyl radical generation, but that they directly oxidized the major plant antioxidant, l-ascorbic acid. Overall, the data presented shed light on mechanisms of the impact of nanosilver on plant cells, and show that these include the induction of classical stress signalling reactions (mediated by [Ca(2+) ]cyt and ROS) and a specific effect on the plasma membrane conductance and the reduced ascorbate. © 2015 The Authors The Plant Journal © 2015 John Wiley & Sons Ltd.

  8. Genotype x environment interaction QTL mapping in plants: lessons from Arabidopsis

    NARCIS (Netherlands)

    El-Soda, M.; Malosetti, M.; Zwaan, B.J.; Koornneef, M.; Aarts, M.G.M.

    2014-01-01

    Plant growth and development are influenced by the genetic composition of the plant (G), the environment (E), and the interaction between them (G × E). To produce suitable genotypes for multiple environments, G × E should be accounted for and assessed in plant-breeding programs. Here, we review the

  9. Cesium-137 accumulation in higher plants before and after Chernobyl

    International Nuclear Information System (INIS)

    Sawidis, T.; Drossos, E.; Papastefanou, C.; Heinrick, G.

    1990-01-01

    Cesium-137 concentrations in plant species of three biotypes of northern Greece, differing in location as well as in vegetation, are reported following the Chernobyl reactor accident. The cesium uptake by plants was due to the foliar deposition rather than the root uptake. The highest level of cesium in plants was found in Ranunculus sardous, a pubescent plant. The 137 Cs concentration was about 22kBq kg -1 d.w. A high level of cesium was also found in Salix alba ( 137 Cs: 19.6 kBq kg -1 d.w.), a deciduous tree showing that hairy leaves or leaves having rough and large surfaces can absorb greater amounts of radioactivity (surface effect). A comparison is also made between the results of measurements of the present study and the results of measurements of some herbarium plants collected one year before the accident as well as the results of measurements of some new plants grown and collected one year after the accident resulting in a natural removal rate of 137 Cs in plants varying from 14 to 130 days

  10. Reconciling functions and evolution of isoprene emission in higher plants.

    Science.gov (United States)

    Loreto, Francesco; Fineschi, Silvia

    2015-04-01

    Compilation and analysis of existing inventories reveal that isoprene is emitted by c. 20% of the perennial vegetation of tropical and temperate regions of the world. Isoprene emitters are found across different plant families without any clear phylogenetic thread. However, by critically appraising information in inventories, several ecological patterns of isoprene emission can be highlighted, including absence of emission from C4 and annual plants, and widespread emission from perennial and deciduous plants of temperate environments. Based on this analysis, and on available information on biochemistry, ecology and functional roles of isoprene, it is suggested that isoprene may not have evolved to help plants face heavy or prolonged stresses, but rather assists C3 plants to run efficient photosynthesis and to overcome transient and mild stresses, especially during periods of active plant growth in warm seasons. When the stress status persists, or when evergreen leaves cope with multiple and repeated stresses, isoprene biosynthesis is replaced by the synthesis of less volatile secondary compounds, in part produced by the same biochemical pathway, thus indicating causal determinism in the evolution of isoprene-emitting plants in response to the environment. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  11. The maize INDETERMINATE1 flowering time regulator defines a highly conserved zinc finger protein family in higher plants

    Directory of Open Access Journals (Sweden)

    Colasanti Joseph

    2006-06-01

    Full Text Available Abstract Background The maize INDETERMINATE1 gene, ID1, is a key regulator of the transition to flowering and the founding member of a transcription factor gene family that encodes a protein with a distinct arrangement of zinc finger motifs. The zinc fingers and surrounding sequence make up the signature ID domain (IDD, which appears to be found in all higher plant genomes. The presence of zinc finger domains and previous biochemical studies showing that ID1 binds to DNA suggests that members of this gene family are involved in transcriptional regulation. Results Comparison of IDD genes identified in Arabidopsis and rice genomes, and all IDD genes discovered in maize EST and genomic databases, suggest that ID1 is a unique member of this gene family. High levels of sequence similarity amongst all IDD genes from maize, rice and Arabidopsis suggest that they are derived from a common ancestor. Several unique features of ID1 suggest that it is a divergent member of the maize IDD family. Although no clear ID1 ortholog was identified in the Arabidopsis genome, highly similar genes that encode proteins with identity extending beyond the ID domain were isolated from rice and sorghum. Phylogenetic comparisons show that these putative orthologs, along with maize ID1, form a group separate from other IDD genes. In contrast to ID1 mRNA, which is detected exclusively in immature leaves, several maize IDD genes showed a broad range of expression in various tissues. Further, Western analysis with an antibody that cross-reacts with ID1 protein and potential orthologs from rice and sorghum shows that all three proteins are detected in immature leaves only. Conclusion Comparative genomic analysis shows that the IDD zinc finger family is highly conserved among both monocots and dicots. The leaf-specific ID1 expression pattern distinguishes it from other maize IDD genes examined. A similar leaf-specific localization pattern was observed for the putative ID1 protein

  12. CRISPR/Cas9-mediated gene targeting in Arabidopsis using sequential transformation.

    Science.gov (United States)

    Miki, Daisuke; Zhang, Wenxin; Zeng, Wenjie; Feng, Zhengyan; Zhu, Jian-Kang

    2018-05-17

    Homologous recombination-based gene targeting is a powerful tool for precise genome modification and has been widely used in organisms ranging from yeast to higher organisms such as Drosophila and mouse. However, gene targeting in higher plants, including the most widely used model plant Arabidopsis thaliana, remains challenging. Here we report a sequential transformation method for gene targeting in Arabidopsis. We find that parental lines expressing the bacterial endonuclease Cas9 from the egg cell- and early embryo-specific DD45 gene promoter can improve the frequency of single-guide RNA-targeted gene knock-ins and sequence replacements via homologous recombination at several endogenous sites in the Arabidopsis genome. These heritable gene targeting can be identified by regular PCR. Our approach enables routine and fine manipulation of the Arabidopsis genome.

  13. Higher plant acclimation to solar ultraviolet-B radiation

    International Nuclear Information System (INIS)

    Robberecht, R.

    1981-01-01

    The objectives of this study were to determine: (1) the relationship between plant sensitivity and epidermal uv attenuation, (2) the effect of phenotypic changes in the leaf epidermis, resulting from uv-B exposure, on plant sensitivity to uv radiation, and (3) the platicity of these changes in the epidermis leading to plant acclimation to uv-B radiation. A mechanism of uv-B attenuation, possibly involving the biosynthesis of uv-absorbing flavonoid compounds in the epidermis and mesophyll under the stress of uv-B radiation, and a subsequent increase in the uv-B attenuation capacity of the epidermis, is suggested. The degree of plant sensitivity and acclimation to natural and intensified solar uv-B radiation may involve a dynamic balance between the capacity for uv-B attenuation and uv-radiation-repair mechanisms in the leaf

  14. An Intergenic Region Shared by At4g35985 and At4g35987 in Arabidopsis thaliana Is a Tissue Specific and Stress Inducible Bidirectional Promoter Analyzed in Transgenic Arabidopsis and Tobacco Plants

    Science.gov (United States)

    Banerjee, Joydeep; Sahoo, Dipak Kumar; Dey, Nrisingha; Houtz, Robert L.; Maiti, Indu Bhushan

    2013-01-01

    On chromosome 4 in the Arabidopsis genome, two neighboring genes (calmodulin methyl transferase At4g35987 and senescence associated gene At4g35985) are located in a head-to-head divergent orientation sharing a putative bidirectional promoter. This 1258 bp intergenic region contains a number of environmental stress responsive and tissue specific cis-regulatory elements. Transcript analysis of At4g35985 and At4g35987 genes by quantitative real time PCR showed tissue specific and stress inducible expression profiles. We tested the bidirectional promoter-function of the intergenic region shared by the divergent genes At4g35985 and At4g35987 using two reporter genes (GFP and GUS) in both orientations in transient tobacco protoplast and Agro-infiltration assays, as well as in stably transformed transgenic Arabidopsis and tobacco plants. In transient assays with GFP and GUS reporter genes the At4g35985 promoter (P85) showed stronger expression (about 3.5 fold) compared to the At4g35987 promoter (P87). The tissue specific as well as stress responsive functional nature of the bidirectional promoter was evaluated in independent transgenic Arabidopsis and tobacco lines. Expression of P85 activity was detected in the midrib of leaves, leaf trichomes, apical meristemic regions, throughout the root, lateral roots and flowers. The expression of P87 was observed in leaf-tip, hydathodes, apical meristem, root tips, emerging lateral root tips, root stele region and in floral tissues. The bidirectional promoter in both orientations shows differential up-regulation (2.5 to 3 fold) under salt stress. Use of such regulatory elements of bidirectional promoters showing spatial and stress inducible promoter-functions in heterologous system might be an important tool for plant biotechnology and gene stacking applications. PMID:24260266

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

    Directory of Open Access Journals (Sweden)

    Joydeep Banerjee

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

  16. Root excretions in tobacco plants and possible implications on the Iron nutrition of higher plants

    Energy Technology Data Exchange (ETDEWEB)

    Wallace, A

    1969-01-01

    Several pieces of evidence indicate that riboflavin produced in roots and perhaps other compounds produced either in roots or in microorganisms can facilitate either or both the absorption and translocation of iron in higher plants. Riboflavin production and increased iron transport are characteristic of iron-deficient plants, both are decreased by nitrogen deficiency, both evidently can be regulated by a microorganism. When large amounts of iron was transported in the xylem exudate of tobacco, riboflavin was also. An excess of the chelating agent, EDTA, without iron seems to increase the iron uptake from an iron chelate, EDDHA. All these effects are probably related and knowledge of them may help solve iron deficiency problems in horticultural crops.

  17. Regulation of phosphate starvation responses in higher plants.

    Science.gov (United States)

    Yang, Xiao Juan; Finnegan, Patrick M

    2010-04-01

    Phosphorus (P) is often a limiting mineral nutrient for plant growth. Many soils worldwide are deficient in soluble inorganic phosphate (P(i)), the form of P most readily absorbed and utilized by plants. A network of elaborate developmental and biochemical adaptations has evolved in plants to enhance P(i) acquisition and avoid starvation. Controlling the deployment of adaptations used by plants to avoid P(i) starvation requires a sophisticated sensing and regulatory system that can integrate external and internal information regarding P(i) availability. In this review, the current knowledge of the regulatory mechanisms that control P(i) starvation responses and the local and long-distance signals that may trigger P(i) starvation responses are discussed. Uncharacterized mutants that have P(i)-related phenotypes and their potential to give us additional insights into regulatory pathways and P(i) starvation-induced signalling are also highlighted and assessed. An impressive list of factors that regulate P(i) starvation responses is now available, as is a good deal of knowledge regarding the local and long-distance signals that allow a plant to sense and respond to P(i) availability. However, we are only beginning to understand how these factors and signals are integrated with one another in a regulatory web able to control the range of responses demonstrated by plants grown in low P(i) environments. Much more knowledge is needed in this agronomically important area before real gains can be made in improving P(i) acquisition in crop plants.

  18. Apple latent spherical virus vectors for reliable and effective virus-induced gene silencing among a broad range of plants including tobacco, tomato, Arabidopsis thaliana, cucurbits, and legumes

    International Nuclear Information System (INIS)

    Igarashi, Aki; Yamagata, Kousuke; Sugai, Tomokazu; Takahashi, Yukari; Sugawara, Emiko; Tamura, Akihiro; Yaegashi, Hajime; Yamagishi, Noriko; Takahashi, Tsubasa; Isogai, Masamichi; Takahashi, Hideki; Yoshikawa, Nobuyuki

    2009-01-01

    Apple latent spherical virus (ALSV) vectors were evaluated for virus-induced gene silencing (VIGS) of endogenous genes among a broad range of plant species. ALSV vectors carrying partial sequences of a subunit of magnesium chelatase (SU) and phytoene desaturase (PDS) genes induced highly uniform knockout phenotypes typical of SU and PDS inhibition on model plants such as tobacco and Arabidopsis thaliana, and economically important crops such as tomato, legume, and cucurbit species. The silencing phenotypes persisted throughout plant growth in these plants. In addition, ALSV vectors could be successfully used to silence a meristem gene, proliferating cell nuclear antigen and disease resistant N gene in tobacco and RCY1 gene in A. thaliana. As ALSV infects most host plants symptomlessly and effectively induces stable VIGS for long periods, the ALSV vector is a valuable tool to determine the functions of interested genes among a broad range of plant species.

  19. Lack of mitochondrial thioredoxin o1 is compensated by antioxidant components under salinity in Arabidopsis thaliana plants.

    Science.gov (United States)

    Calderón, Aingeru; Sánchez-Guerrero, Antonio; Ortiz-Espín, Ana; Martínez-Alcalá, Isabel; Camejo, Daymi; Jiménez, Ana; Sevilla, Francisca

    2018-02-15

    In a changing environment, plants are able to acclimate to the new conditions by regulating their metabolism through the antioxidant and redox systems involved in the stress response. Here we studied a mitochondrial thioredoxin in wild type (WT) Arabidopis thaliana and two Attrxo1 mutant lines grown in the absence or presence of 100 mM NaCl. Compared to WT plants, no evident phenotype was observed in the mutant plants in control condition, although they had higher number of stomata, loss of water, nitric oxide and carbonyl protein contents as well as higher activity of superoxide dismutase (SOD) and catalase enzymes than WT plants. Under salinity, the mutants presented lower water loss and higher stomatal closure, H 2 O 2 and lipid peroxidation levels accompanied by higher enzymatic activity of catalase and the different SOD isoenzymes compared to WT plants. These inductions may collaborate in the maintenance of plant integrity and growth observed under saline conditions, possibly as a way to compensate the lack of TRXo1. We discuss the potential of TRXo1 to influence the development of the whole plant under saline conditions, which have great value for the agronomy of plants growing under unfavourable environment. This article is protected by copyright. All rights reserved.

  20. Influence of surface polysaccharides of Escherichia coli O157:H7 on plant defense response and survival of the human enteric pathogen on Arabidopsis thaliana and lettuce (Lactuca sativa).

    Science.gov (United States)

    Jang, Hyein; Matthews, Karl R

    2018-04-01

    This study aimed to determine the influence of bacterial surface polysaccharides (cellulose, colanic acid, and lipopolysaccharide; LPS) on the colonization or survival of Escherichia coli O157:H7 on plants and the plant defense response. Survival of E. coli O157:H7 were evaluated on Arabidopsis thaliana and romaine lettuce as a model plant and an edible crop (leafy vegetable), respectively. The population of the wild-type strain of E. coli O157:H7 on Arabidopsis plants and lettuce was significantly (P lettuce regardless of day post-inoculation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Plant phenotype - Arabidopsis Phenome Database | LSDB Archive [Life Science Database Archive metadata

    Lifescience Database Archive (English)

    Full Text Available of organs, tissues, development stages. The vocabulary is defined in Plant Ontology(PO). Qualities: Characte...ristics, attributes of entities. The vocabulary is defined in Phenotype Ontology(PATO). Data file File name:...w/riken_piam_phenome#en Data acquisition method Plant Ontology, Phenotype Ontology Data analysis method - Nu

  2. Validation of the high-throughput marker technology DArT using the model plant Arabidopsis thaliana.

    Science.gov (United States)

    Wittenberg, Alexander H J; van der Lee, Theo; Cayla, Cyril; Kilian, Andrzej; Visser, Richard G F; Schouten, Henk J

    2005-08-01

    Diversity Arrays Technology (DArT) is a microarray-based DNA marker technique for genome-wide discovery and genotyping of genetic variation. DArT allows simultaneous scoring of hundreds of restriction site based polymorphisms between genotypes and does not require DNA sequence information or site-specific oligonucleotides. This paper demonstrates the potential of DArT for genetic mapping by validating the quality and molecular basis of the markers, using the model plant Arabidopsis thaliana. Restriction fragments from a genomic representation of the ecotype Landsberg erecta (Ler) were amplified by PCR, individualized by cloning and spotted onto glass slides. The arrays were then hybridized with labeled genomic representations of the ecotypes Columbia (Col) and Ler and of individuals from an F(2) population obtained from a Col x Ler cross. The scoring of markers with specialized software was highly reproducible and 107 markers could unambiguously be ordered on a genetic linkage map. The marker order on the genetic linkage map coincided with the order on the DNA sequence map. Sequencing of the Ler markers and alignment with the available Col genome sequence confirmed that the polymorphism in DArT markers is largely a result of restriction site polymorphisms.

  3. Plant-specific Histone Deacetylases HDT½ Regulate GIBBERELLIN 2-OXIDASE 2 Expression to Control Arabidopsis Root Meristem Cell Number

    KAUST Repository

    Li, Huchen

    2017-08-31

    Root growth is modulated by environmental factors and depends on cell production in the root meristem (RM). New cells in the meristem are generated by stem cells and transit-amplifying cells, which together determine RM cell number. Transcription factors and chromatin-remodelling factors have been implicated in regulating the switch from stem cells to transit-amplifying cells. Here we show that two Arabidopsis thaliana paralogs encoding plant-specific histone deacetylases, HDT1 and HDT2, regulate a second switch from transit-amplifying cells to expanding cells. Knockdown of HDT½ (hdt1,2i) results in an earlier switch and causes a reduced RM cell number. Our data show that HDT½ negatively regulate the acetylation level of the C19-GIBBERELLIN 2-OXIDASE 2 (GA2ox2) locus and repress the expression of GA2ox2 in the RM and elongation zone. Overexpression of GA2ox2 in the RM phenocopies the hdt1,2i phenotype. Conversely, knockout of GA2ox2 partially rescues the root growth defect of hdt1,2i. These results suggest that by repressing the expression of GA2ox2, HDT½ likely fine-tune gibberellin metabolism and they are crucial for regulating the switch from cell division to expansion to determine RM cell number. We propose that HDT½ function as part of a mechanism that modulates root growth in response to environmental factors.

  4. Risks of increased UV-B radiation: higher plants

    International Nuclear Information System (INIS)

    Rau, W.; Hofmann, H.

    1994-01-01

    The question pursued within the Bavarian climate research programme (BayFORKLIM) in the present context was as follows: Does the fact that UV-B radiation increases with growing site elevation mean that the low sensitivity of predominantly alpine plants compared with that of lowland plants is attributable to their different genetic constitution, possibly as a result of selective pressure and/or de alpine species have a greater capacity to develop protective mechanisms? Pairs and triplets of species belonging to the same genus but occuring at different site elevations were grown from seeds in a greenhouse that is, without UV-B. In order to determine their capacity to adapt to UV-B radiation, some of the plants were additionally exposed to UV-B for 5-6 weeks prior to sensitivity testing. Sensitivity was tested by exposing the plants to additional UV-B of different intensities in test chambers. Visible damage, ranging from light bronzing or yellowing to withering, served as an assessment criterion. Levels of UV-B absorbing substances (phenylpropane species, usually flavonoids) were also measured in these plants. The results obtained permit the following conclusions: The greater UV-B resistance of alpine species compared with that of lowland species of the same genus is not attributable to their genetic constitution but rather to their superior adaptability. Superior resistance is in part due to a greater accumulation of UV-B absorbing substances. Distinct differences in sensitivity between different genera could lead to population shifts within ecosystems as a result of increased UV-B radiation. (orig./KW) [de

  5. Expression of TpNRAMP5, a metal transporter from Polish wheat (Triticum polonicum L.), enhances the accumulation of Cd, Co and Mn in transgenic Arabidopsis plants.

    Science.gov (United States)

    Peng, Fan; Wang, Chao; Zhu, Jianshu; Zeng, Jian; Kang, Houyang; Fan, Xing; Sha, Lina; Zhang, Haiqin; Zhou, Yonghong; Wang, Yi

    2018-06-01

    TpRNAMP5 is mainly expressed in the plasma membrane of roots and basal stems. It functions as a metal transporter for Cd, Mn and Co accumulation. Numerous natural resistance-associated macrophage proteins (NRAMPs) have been functionally identified in various plant species, including Arabidopsis, rice, soybean and tobacco, but no information is available on NRAMP genes in wheat. In this study, we isolated a TpNRAMP5 from dwarf Polish wheat (DPW, Triticum polonicum L.), a species with high tolerance to Cd and Zn. Expression pattern analysis revealed that TpNRAMP5 is mainly expressed in roots and basal stems of DPW. TpNRAMP5 was localized at the plasma membrane of Arabidopsis leaf protoplast. Expression of TpNRAMP5 in yeast significantly increased yeast sensitivity to Cd and Co, but not Zn, and enhanced Cd and Co concentrations. Expression of TpNRAMP5 in Arabidopsis significantly increased Cd, Co and Mn concentrations in roots, shoots and whole plants, but had no effect on Fe and Zn concentrations. These results indicate that TpNRAMP5 is a metal transporter enhancing the accumulation of Cd, Co and Mn, but not Zn and Fe. Genetic manipulation of TpNRAMP5 can be applied in the future to limit the transfer of Cd from soil to wheat grains, thereby protecting human health.

  6. Flowering responses to light-breaks in photomorphogenic mutants of Arabidopsis thaliana, a long-day plant

    International Nuclear Information System (INIS)

    Goto, N.; Kumagai, T.; Koornneef, M.

    1991-01-01

    Flowering response and plant form of photomorphogenic mutants (hy1, hy2, hy3, hy4 and hy5) of Arabidopsis thaliana (L.), a long-day plant, were examined in long and short days. There were only slight differences among genotypes including Landsberg wild type with respect to the flowering time under long days. The effect of 1 h light-(night)-breaks of far-red, red, blue and white light given in the middle of the dark period of plants grown under short days, was studied. Effects of far-red light applied at the end or the beginning of the main photoperiod on flowering and plant form were also examined. The light-breaks with all the above mentioned light qualities promoted floral initiation of all the genotypes including the wild type in terms of both the flowering time and the number of rosette leaves. In general, far-red light was most effective. It is possible to classify the hy-mutants into 3 groups by their responses to light-breaks under short day conditions: (a) Mutants hy2 and hy3, which have a reduced number of rosette leaves, and flower early. Red light is as effective as far-red light. The wavelength of light-breaks is relatively unimportant for flowering response. (b) Mutants hy4, hy5 and Landsberg wild type, which have a greater number of rosette leaves, and flower relatively late. The effectiveness of light-breaks is in the following order, far-red, blue, and red light, which is in reverse order to the transformation of phytochrome to the P fr form. (c) Mutant hy1, which behaves anomalously with respect to relations between flowering time and number of rosette leaves; late flowering with reduced number of rosette leaves. Red, blue and far-red light are effective, but white light is ineffective for reducing the number of rosette leaves. When far-red light was given in the middle of the night or at the end of the main photoperiod, it markedly reduced the number of rosette leaves compared to those grown under short days for all the genotypes, while when

  7. PHYSIOLOGY OF ION TRANSPORT ACROSS THE TONOPLAST OF HIGHER PLANTS.

    Science.gov (United States)

    Barkla, Bronwyn J.; Pantoja, Omar

    1996-06-01

    The vacuole of plant cells plays an important role in the homeostasis of the cell. It is involved in the regulation of cytoplasmic pH, sequestration of toxic ions and xenobiotics, regulation of cell turgor, storage of amino acids, sugars and CO2 in the form of malate, and possibly as a source for elevating cytoplasmic calcium. All these activities are driven by two primary active transport mechanisms present in the vacuolar membrane (tonoplast). These two mechanisms employ high-energy metabolites to pump protons into the vacuole, establishing a proton electrochemical potential that mediates the transport of a diverse range of solutes. Within the past few years, great advances at the molecular and functional levels have been made on the characterization and identification of these mechanisms. The aim of this review is to summarize these studies in the context of the physiology of the plant cell.

  8. An expanding universe of circadian networks in higher plants.

    Science.gov (United States)

    Pruneda-Paz, Jose L; Kay, Steve A

    2010-05-01

    Extensive circadian clock networks regulate almost every biological process in plants. Clock-controlled physiological responses are coupled with daily oscillations in environmental conditions resulting in enhanced fitness and growth vigor. Identification of core clock components and their associated molecular interactions has established the basic network architecture of plant clocks, which consists of multiple interlocked feedback loops. A hierarchical structure of transcriptional feedback overlaid with regulated protein turnover sets the pace of the clock and ultimately drives all clock-controlled processes. Although originally described as linear entities, increasing evidence suggests that many signaling pathways can act as both inputs and outputs within the overall network. Future studies will determine the molecular mechanisms involved in these complex regulatory loops. 2010 Elsevier Ltd. All rights reserved.

  9. The genome of Arabidopsis thaliana.

    OpenAIRE

    Goodman, H M; Ecker, J R; Dean, C

    1995-01-01

    Arabidopsis thaliana is a small flowering plant that is a member of the family cruciferae. It has many characteristics--diploid genetics, rapid growth cycle, relatively low repetitive DNA content, and small genome size--that recommend it as the model for a plant genome project. The current status of the genetic and physical maps, as well as efforts to sequence the genome, are presented. Examples are given of genes isolated by using map-based cloning. The importance of the Arabidopsis project ...

  10. Northern glacial refugia and altitudinal niche divergence shape genome-wide differentiation in the emerging plant model Arabidopsis arenosa

    Czech Academy of Sciences Publication Activity Database

    Kolář, Filip; Fuxová, G.; Záveská, E.; Nagano, A. J.; Hyklová, L.; Lučanová, Magdalena; Kudoh, H.; Marhold, K.

    2016-01-01

    Roč. 25, č. 16 (2016), s. 3929-3949 ISSN 0962-1083 Institutional support: RVO:67985939 Keywords : approximate Bayesian computatuion * niche differentiation * phytogeography * Arabidopsis Subject RIV: EF - Botanics Impact factor: 6.086, year: 2016

  11. Comparative studies on the photosynthesis of higher plants, 4

    International Nuclear Information System (INIS)

    Imai, Hideo; Iwai, Sumio; Yamada, Yoshio.

    1975-01-01

    In this paper, studies were carried out to confirm whether carbon atoms except C-4 of C 4 -compounds were involved in the photosynthetic sugar formation in C 4 plants. In feeding of uniformly-labeled malate to maize leaves, sugar formation under aerobic conditions was 3 times as large as that under anaerobic conditions. There was no detectable difference in the amount of activity in the sugar formed from β-carboxyl-labeled malate between aerobic and anaerobic conditions; however. Under anaerobic conditions, sugar was formed from alanine-1- 14 C in maize but not in rice leaves. Sugar formation of this case might have occurred by the direct conversion of pyruvate to sugar via PEP and PGA. From these results, we assume that the following three pathways function cooperatively in the photosynthetic sugar formation in C 4 -plants. 1) One carbon atom at number 4 in C 4 -dicarboxylic acid is transferred to RuDP, resulting in the formation of PGA and this is metabolized into sugar. 2) After transferring C-4 of C 4 -dicarboxylic acid, the remaining C 3 -compound is introduced into the TCA cycle and completely degradated there, and thus-produced CO 2 is refixed by PEP carboxylase in the mesophyll and metabolized into sugar the same pathway as in atmospheric CO 2 fixation. 3) The remaining C 3 -compound is directly converted to PEP and then to sugar via PGA. (auth.)

  12. Mechanistic studies of ethylene biosynthesis in higher plants

    International Nuclear Information System (INIS)

    McGeehan, G.M.

    1986-01-01

    Ethylene is a plant hormone that elicits a wide variety of responses in plant tissue. Among these responses are the hastening of abscission, ripening and senescence. In 1979 it was discovered that 1-amino-1-cyclopropane carboxylic acid is the immediate biosynthetic precursor to ethylene. Given the obvious economic significance of ethylene production the authors concentrated their studies on the conversion of ACC to ethylene. They delved into mechanistic aspects of ACC oxidation and they studied potential inhibitors of ethylene forming enzyme (EFE). They synthesized various analogs of ACC and found that EFE shows good stereodiscrimination among alkyl substituted ACC analogs with the 1R, 2S stereoisomer being processed nine times faster than the 1S, 2R isomer in the MeACC series. They also synthesized 2-cyclopropyl ACC which is a good competitive inhibitor of EFE. This compound also causes time dependent loss of EFE activity leading us to believe it is an irreversible inhibitor of ethylene formation. The synthesis of these analogs has also allowed them to develop a spectroscopic technique to assign the relative stereochemistry of alkyl groups. 13 C NMR allows them to assign the alkyl stereochemistry based upon gamma-shielding effects on the carbonyl resonance. Lastly, they measured kinetic isotope effects on the oxidation of ACC in vivo and in vitro and found that ACC is oxidized by a rate-determining 1-electron removal from nitrogen in close accord with mechanisms for the oxidation of other alkyl amines

  13. Molecular aspects of plant disease susceptibility: Arabidopsis genes affecting downy mildew infection

    NARCIS (Netherlands)

    Lapin, D.

    2013-01-01

    Interactions of plants with pathogenic microorganisms are influenced by multiple biotic and abiotic factors. The host immune system can detect pathogens and restrict their growth and development, but also non-immunity related host factors and processes can contribute to pathogenesis by attracting

  14. Pivoting from Arabidopsis to wheat to understand how agricultural plants integrate responses to biotic stress

    Science.gov (United States)

    Here we argue for a research initiative on gene-for-gene (g-f-g) interactions between wheat and its parasites. One aim is to begin a conversation between the disparate communities of plant pathology and entomology. Another is to understand how responses to biotic stress are integrated in an import...

  15. Unearthing Bacillus endophytes from desert plants that enhance growth of Arabidopsis thaliana under abiotic stress conditions

    KAUST Repository

    Bokhari, Ameerah

    2018-01-01

    that these bacteria can confer resilience to plants under salt stress conditions. B. circulans (PK3-15 and PK3-109), B. cereus (PK6-15) B. subtilis (PK3-9) and B. licheniformis (PK5-26) displayed the ability to increased the fresh weight of A. thaliana under salt

  16. The Potential of Text Mining in Data Integration and Network Biology for Plant Research: A Case Study on Arabidopsis[C][W

    Science.gov (United States)

    Van Landeghem, Sofie; De Bodt, Stefanie; Drebert, Zuzanna J.; Inzé, Dirk; Van de Peer, Yves

    2013-01-01

    Despite the availability of various data repositories for plant research, a wealth of information currently remains hidden within the biomolecular literature. Text mining provides the necessary means to retrieve these data through automated processing of texts. However, only recently has advanced text mining methodology been implemented with sufficient computational power to process texts at a large scale. In this study, we assess the potential of large-scale text mining for plant biology research in general and for network biology in particular using a state-of-the-art text mining system applied to all PubMed abstracts and PubMed Central full texts. We present extensive evaluation of the textual data for Arabidopsis thaliana, assessing the overall accuracy of this new resource for usage in plant network analyses. Furthermore, we combine text mining information with both protein–protein and regulatory interactions from experimental databases. Clusters of tightly connected genes are delineated from the resulting network, illustrating how such an integrative approach is essential to grasp the current knowledge available for Arabidopsis and to uncover gene information through guilt by association. All large-scale data sets, as well as the manually curated textual data, are made publicly available, hereby stimulating the application of text mining data in future plant biology studies. PMID:23532071

  17. Transgenic tobacco plants having a higher level of methionine are more sensitive to oxidative stress.

    Science.gov (United States)

    Hacham, Yael; Matityahu, Ifat; Amir, Rachel

    2017-07-01

    Methionine is an essential amino acid the low level of which limits the nutritional quality of plants. We formerly produced transgenic tobacco (Nicotiana tabacum) plants overexpressing CYSTATHIONE γ-SYNTHASE (CGS) (FA plants), methionine's main regulatory enzyme. These plants accumulate significantly higher levels of methionine compared with wild-type (WT) plants. The aim of this study was to gain more knowledge about the effect of higher methionine content on the metabolic profile of vegetative tissue and on the morphological and physiological phenotypes. FA plants exhibit slightly reduced growth, and metabolic profiling analysis shows that they have higher contents of stress-related metabolites. Despite this, FA plants were more sensitive to short- and long-term oxidative stresses. In addition, compared with WT plants and transgenic plants expressing an empty vector, the primary metabolic profile of FA was altered less during oxidative stress. Based on morphological and metabolic phenotypes, we strongly proposed that FA plants having higher levels of methionine suffer from stress under non-stress conditions. This might be one of the reasons for their lesser ability to cope with oxidative stress when it appeared. The observation that their metabolic profiling is much less responsive to stress compared with control plants indicates that the delta changes in metabolite contents between non-stress and stress conditions is important for enabling the plants to cope with stress conditions. © 2017 Scandinavian Plant Physiology Society.

  18. The Arabidopsis Rho of Plants GTPase AtROP6 Functions in Developmental and Pathogen Response Pathways1[C][W][OA

    Science.gov (United States)

    Poraty-Gavra, Limor; Zimmermann, Philip; Haigis, Sabine; Bednarek, Paweł; Hazak, Ora; Stelmakh, Oksana Rogovoy; Sadot, Einat; Schulze-Lefert, Paul; Gruissem, Wilhelm; Yalovsky, Shaul

    2013-01-01

    How plants coordinate developmental processes and environmental stress responses is a pressing question. Here, we show that Arabidopsis (Arabidopsis thaliana) Rho of Plants6 (AtROP6) integrates developmental and pathogen response signaling. AtROP6 expression is induced by auxin and detected in the root meristem, lateral root initials, and leaf hydathodes. Plants expressing a dominant negative AtROP6 (rop6DN) under the regulation of its endogenous promoter are small and have multiple inflorescence stems, twisted leaves, deformed leaf epidermis pavement cells, and differentially organized cytoskeleton. Microarray analyses of rop6DN plants revealed that major changes in gene expression are associated with constitutive salicylic acid (SA)-mediated defense responses. In agreement, their free and total SA levels resembled those of wild-type plants inoculated with a virulent powdery mildew pathogen. The constitutive SA-associated response in rop6DN was suppressed in mutant backgrounds defective in SA signaling (nonexpresser of PR genes1 [npr1]) or biosynthesis (salicylic acid induction deficient2 [sid2]). However, the rop6DN npr1 and rop6DN sid2 double mutants retained the aberrant developmental phenotypes, indicating that the constitutive SA response can be uncoupled from ROP function(s) in development. rop6DN plants exhibited enhanced preinvasive defense responses to a host-adapted virulent powdery mildew fungus but were impaired in preinvasive defenses upon inoculation with a nonadapted powdery mildew. The host-adapted powdery mildew had a reduced reproductive fitness on rop6DN plants, which was retained in mutant backgrounds defective in SA biosynthesis or signaling. Our findings indicate that both the morphological aberrations and altered sensitivity to powdery mildews of rop6DN plants result from perturbations that are independent from the SA-associated response. These perturbations uncouple SA-dependent defense signaling from disease resistance execution. PMID

  19. Cycling of clock genes entrained to the solar rhythm enables plants to tell time: data from Arabidopsis.

    Science.gov (United States)

    Yeang, Hoong-Yeet

    2015-07-01

    An endogenous rhythm synchronized to dawn cannot time photosynthesis-linked genes to peak consistently at noon since the interval between sunrise and noon changes seasonally. In this study, a solar clock model that circumvents this limitation is proposed using two daily timing references synchronized to noon and midnight. Other rhythmic genes that are not directly linked to photosynthesis, and which peak at other times, also find an adaptive advantage in entrainment to the solar rhythm. Fourteen datasets extracted from three published papers were used in a meta-analysis to examine the cyclic behaviour of the Arabidopsis thaliana photosynthesis-related gene CAB2 and the clock oscillator genes TOC1 and LHY in T cycles and N-H cycles. Changes in the rhythms of CAB2, TOC1 and LHY in plants subjected to non-24-h light:dark cycles matched the hypothesized changes in their behaviour as predicted by the solar clock model, thus validating it. The analysis further showed that TOC1 expression peaked ∼5·5 h after mid-day, CAB2 peaked close to noon, while LHY peaked ∼7·5 h after midnight, regardless of the cycle period, the photoperiod or the light:dark period ratio. The solar clock model correctly predicted the zeitgeber timing of these genes under 11 different lighting regimes comprising combinations of seven light periods, nine dark periods, four cycle periods and four light:dark period ratios. In short cycles that terminated before LHY could be expressed, the solar clock correctly predicted zeitgeber timing of its expression in the following cycle. Regulation of gene phases by the solar clock enables the plant to tell the time, by which means a large number of genes are regulated. This facilitates the initiation of gene expression even before the arrival of sunrise, sunset or noon, thus allowing the plant to 'anticipate' dawn, dusk or mid-day respectively, independently of the photoperiod. © The Author 2015. Published by Oxford University Press on behalf of the

  20. Cycling of clock genes entrained to the solar rhythm enables plants to tell time: data from arabidopsis

    Science.gov (United States)

    Yeang, Hoong-Yeet

    2015-01-01

    Background and Aims An endogenous rhythm synchronized to dawn cannot time photosynthesis-linked genes to peak consistently at noon since the interval between sunrise and noon changes seasonally. In this study, a solar clock model that circumvents this limitation is proposed using two daily timing references synchronized to noon and midnight. Other rhythmic genes that are not directly linked to photosynthesis, and which peak at other times, also find an adaptive advantage in entrainment to the solar rhythm. Methods Fourteen datasets extracted from three published papers were used in a meta-analysis to examine the cyclic behaviour of the Arabidopsis thaliana photosynthesis-related gene CAB2 and the clock oscillator genes TOC1 and LHY in T cycles and N–H cycles. Key Results Changes in the rhythms of CAB2, TOC1 and LHY in plants subjected to non-24-h light:dark cycles matched the hypothesized changes in their behaviour as predicted by the solar clock model, thus validating it. The analysis further showed that TOC1 expression peaked ∼5·5 h after mid-day, CAB2 peaked close to noon, while LHY peaked ∼7·5 h after midnight, regardless of the cycle period, the photoperiod or the light:dark period ratio. The solar clock model correctly predicted the zeitgeber timing of these genes under 11 different lighting regimes comprising combinations of seven light periods, nine dark periods, four cycle periods and four light:dark period ratios. In short cycles that terminated before LHY could be expressed, the solar clock correctly predicted zeitgeber timing of its expression in the following cycle. Conclusions Regulation of gene phases by the solar clock enables the plant to tell the time, by which means a large number of genes are regulated. This facilitates the initiation of gene expression even before the arrival of sunrise, sunset or noon, thus allowing the plant to ‘anticipate’ dawn, dusk or mid-day respectively, independently of the photoperiod. PMID:26070640

  1. Unearthing Bacillus endophytes from desert plants that enhance growth of Arabidopsis thaliana under abiotic stress conditions

    KAUST Repository

    Bokhari, Ameerah M

    2018-04-01

    Here, we embarked a bioprospecting project that focuses on the isolation and characterization of plant root endophytes, collected from the Thar Desert. A total of 381 endophytes were isolated and based on their 16S rRNA gene sequences, genus Bacillus (58 strains) was identified as the major taxon and only endophytes from this genus were isolated from all plant types. Of the 58 Bacillus strains, only 16 strains were selected for screening of plant growth promotion traits such as P and Zn solubilization, indole-3-acetic acid and siderophore production, and antimicrobial activity. Based on the presence of specific plant growth promotion traits 10 strains were shortlisted for further in vitro screening with A. thaliana; to confirm that these bacteria can confer resilience to plants under salt stress conditions. B. circulans (PK3-15 and PK3-109), B. cereus (PK6-15) B. subtilis (PK3-9) and B. licheniformis (PK5-26) displayed the ability to increased the fresh weight of A. thaliana under salt stress conditions by more than 50 % compared to the uninoculated control. An interesting observation was that B. circulans (PK3-109) (shown to produce IAA exopolysaccharide) and B. circulans (PK3-138) (shown to produce IAA) in vitro results were substantially different as B. circulans (PK3-138) decreased the total fresh weight of A. thaliana by 47 %, whilst B. circulans (PK3-109) was one of the best performing strains. Thus, the genomes of these two strains were sequences to unravel the molecular versatility of B. circulans strains, specifically with respect to their interaction with plants. Most of the genome of these strains is identical but the most interesting feature was the presence of 1/ the DegS–DegU two-component system that is known to mediate the salt stress response and DegU also represses toxin wapA similar to antitoxin wapI, and 2/ YxiG, a gene in the unique orthogroup of PK3-109 was found to be linked to WapI. Thus, PK3-138 substantially decreasing the total fresh

  2. Linkage disequilibrium between incompatibility locus region genes in the plant Arabidopsis lyrata

    DEFF Research Database (Denmark)

    Hagenblad, Jenny; Bechsgaard, Jesper Smærup; Charlesworth, Deborah

    2006-01-01

    to the incompatibility locus, one being a pseudogene. We determined the phase of multiple haplotypes in families of plants from Icelandic and other populations. Different Aly8 sequence types are associated with different SRK alleles, while haplotypes with the same SRK sequences tend to have the same Aly8 sequence...... the evolutionary history of these populations. Overall, the results suggest that recombination rarely occurs in the interval between the S-loci and Aly8 and that linkage to the S-loci can probably account for the observed high Aly8 diversity....

  3. Key Components of Different Plant Defense Pathways Are Dispensable for Powdery Mildew Resistance of the Arabidopsis mlo2 mlo6 mlo12 Triple Mutant.

    Science.gov (United States)

    Kuhn, Hannah; Lorek, Justine; Kwaaitaal, Mark; Consonni, Chiara; Becker, Katia; Micali, Cristina; Ver Loren van Themaat, Emiel; Bednarek, Paweł; Raaymakers, Tom M; Appiano, Michela; Bai, Yuling; Meldau, Dorothea; Baum, Stephani; Conrath, Uwe; Feussner, Ivo; Panstruga, Ralph

    2017-01-01

    Loss of function mutations of particular plant MILDEW RESISTANCE LOCUS O ( MLO ) genes confer durable and broad-spectrum penetration resistance against powdery mildew fungi. Here, we combined genetic, transcriptomic and metabolomic analyses to explore the defense mechanisms in the fully resistant Arabidopsis thaliana mlo2 mlo6 mlo12 triple mutant. We found that this genotype unexpectedly overcomes the requirement for indolic antimicrobials and defense-related secretion, which are critical for incomplete resistance of mlo2 single mutants. Comparative microarray-based transcriptome analysis of mlo2 mlo6 mlo12 mutants and wild type plants upon Golovinomyces orontii inoculation revealed an increased and accelerated accumulation of many defense-related transcripts. Despite the biotrophic nature of the interaction, this included the non-canonical activation of a jasmonic acid/ethylene-dependent transcriptional program. In contrast to a non-adapted powdery mildew pathogen, the adapted powdery mildew fungus is able to defeat the accumulation of defense-relevant indolic metabolites in a MLO protein-dependent manner. We suggest that a broad and fast activation of immune responses in mlo2 mlo6 mlo12 plants can compensate for the lack of single or few defense pathways. In addition, our results point to a role of Arabidopsis MLO2, MLO6, and MLO12 in enabling defense suppression during invasion by adapted powdery mildew fungi.

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

    International Nuclear Information System (INIS)

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

    2015-01-01

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

  5. Analysis of plant growth-promoting properties of Bacillus amyloliquefaciens UCMB5113 using Arabidopsis thaliana as host plant

    Czech Academy of Sciences Publication Activity Database

    Asari, S.; Tarkowská, Danuše; Rolčík, Jakub; Novák, Ondřej; Palmero, D. V.; Bejai, S.; Meijer, J.

    2017-01-01

    Roč. 245, č. 1 (2017), s. 15-30 ISSN 0032-0935 R&D Projects: GA MŠk LK21306; GA MŠk(CZ) LO1204; GA ČR GA14-34792S Institutional support: RVO:61389030 Keywords : rape brassica-napus * cell elongation * root-growth * rhizobacteria * gibberellins * bacteria * cytokinin * seedlings * defense * stress * Beneficial bacteria * Biocontrol * Growth promotion * Phytohormones * Rhizosphere * Root structure Subject RIV: EF - Botanics OBOR OECD: Plant sciences, botany Impact factor: 3.361, year: 2016

  6. Effects of the Extraterrestrial Environment on Plants: Recommendations for Future Space Experiments for the MELiSSA Higher Plant Compartment

    Directory of Open Access Journals (Sweden)

    Silje A. Wolff

    2014-05-01

    Full Text Available Due to logistical challenges, long-term human space exploration missions require a life support system capable of regenerating all the essentials for survival. Higher plants can be utilized to provide a continuous supply of fresh food, atmosphere revitalization, and clean water for humans. Plants can adapt to extreme environments on Earth, and model plants have been shown to grow and develop through a full life cycle in microgravity. However, more knowledge about the long term effects of the extraterrestrial environment on plant growth and development is necessary. The European Space Agency (ESA has developed the Micro-Ecological Life Support System Alternative (MELiSSA program to develop a closed regenerative life support system, based on micro-organisms and higher plant processes, with continuous recycling of resources. In this context, a literature review to analyze the impact of the space environments on higher plants, with focus on gravity levels, magnetic fields and radiation, has been performed. This communication presents a roadmap giving directions for future scientific activities within space plant cultivation. The roadmap aims to identify the research activities required before higher plants can be included in regenerative life support systems in space.

  7. Polyploidization increases meiotic recombination frequency in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Rehmsmeier Marc

    2011-04-01

    Full Text Available Abstract Background Polyploidization is the multiplication of the whole chromosome complement and has occurred frequently in vascular plants. Maintenance of stable polyploid state over generations requires special mechanisms to control pairing and distribution of more than two homologous chromosomes during meiosis. Since a minimal number of crossover events is essential for correct chromosome segregation, we investigated whether polyploidy has an influence on the frequency of meiotic recombination. Results Using two genetically linked transgenes providing seed-specific fluorescence, we compared a high number of progeny from diploid and tetraploid Arabidopsis plants. We show that rates of meiotic recombination in reciprocal crosses of genetically identical diploid and autotetraploid Arabidopsis plants were significantly higher in tetraploids compared to diploids. Although male and female gametogenesis differ substantially in meiotic recombination frequency, both rates were equally increased in tetraploids. To investigate whether multivalent formation in autotetraploids was responsible for the increased recombination rates, we also performed corresponding experiments with allotetraploid plants showing strict bivalent pairing. We found similarly increased rates in auto- and allotetraploids, suggesting that the ploidy effect is independent of chromosome pairing configurations. Conclusions The evolutionary success of polyploid plants in nature and under domestication has been attributed to buffering of mutations and sub- and neo-functionalization of duplicated genes. Should the data described here be representative for polyploid plants, enhanced meiotic recombination, and the resulting rapid creation of genetic diversity, could have also contributed to their prevalence.

  8. The Arabidopsis halophytic relative Thellungiella halophila tolerates nitrogen-limiting conditions by maintaining growth, nitrogen uptake, and assimilation.

    Science.gov (United States)

    Kant, Surya; Bi, Yong-Mei; Weretilnyk, Elizabeth; Barak, Simon; Rothstein, Steven J

    2008-07-01

    A comprehensive knowledge of mechanisms regulating nitrogen (N) use efficiency is required to reduce excessive input of N fertilizers while maintaining acceptable crop yields under limited N supply. Studying plant species that are naturally adapted to low N conditions could facilitate the identification of novel regulatory genes conferring better N use efficiency. Here, we show that Thellungiella halophila, a halophytic relative of Arabidopsis (Arabidopsis thaliana), grows better than Arabidopsis under moderate (1 mm nitrate) and severe (0.4 mm nitrate) N-limiting conditions. Thellungiella exhibited a lower carbon to N ratio than Arabidopsis under N limitation, which was due to Thellungiella plants possessing higher N content, total amino acids, total soluble protein, and lower starch content compared with Arabidopsis. Furthermore, Thellungiella had higher amounts of several metabolites, such as soluble sugars and organic acids, under N-sufficient conditions (4 mm nitrate). Nitrate reductase activity and NR2 gene expression in Thellungiella displayed less of a reduction in response to N limitation than in Arabidopsis. Thellungiella shoot GS1 expression was more induced by low N than in Arabidopsis, while in roots, Thellungiella GS2 expression was maintained under N limitation but was decreased in Arabidopsis. Up-regulation of NRT2.1 and NRT3.1 expression was higher and repression of NRT1.1 was lower in Thellungiella roots under N-limiting conditions compared with Arabidopsis. Differential transporter gene expression was correlated with higher nitrate influx in Thellungiella at low (15)NO(3)(-) supply. Taken together, our results suggest that Thellungiella is tolerant to N-limited conditions and could act as a model system to unravel the mechanisms for low N tolerance.

  9. Induction of early long-range epigenetic changes by α-irradiation in arabidopsis thaliana plants

    International Nuclear Information System (INIS)

    Xu Shuyan; Li Fanghua; Wang Ting; Bian Po; Wu Yuejin

    2011-01-01

    Along the way, the mutagenic mechanism of low-energy ions irradiation is a debatable issue. Recently, the existence of radiation induced long-range (mutagenic) effects in vivo in plants has been performed in a series of studies of our group, which account for the mutagenesis of low-energy ions irradiation in a new perspective. However, numerous distinct biology phenomena remain to be addressed, which bear obvious characteristics to epigenetic.In the present study, using the expression of methylation-related AtDML3 gene and methylation level of specific gene segments as end points, the methylation of cytosine, the most important feature of epigenetic,was investigated. It was shown that, in A. thaliana, root-localized α-irradiation could induce epigenetic changes in aerial parts which avoided the direct irradiation. The radiation induced long-range epigenetic changes were confirmed in this study, which supplied innovative ideas for the further investigation of the mutagenetic mechanism of low-energy ions irradiation. (authors)

  10. Transgenic Arabidopsis Gene Expression System

    Science.gov (United States)

    Ferl, Robert; Paul, Anna-Lisa

    2009-01-01

    The Transgenic Arabidopsis Gene Expression System (TAGES) investigation is one in a pair of investigations that use the Advanced Biological Research System (ABRS) facility. TAGES uses Arabidopsis thaliana, thale cress, with sensor promoter-reporter gene constructs that render the plants as biomonitors (an organism used to determine the quality of the surrounding environment) of their environment using real-time nondestructive Green Fluorescent Protein (GFP) imagery and traditional postflight analyses.

  11. Structure-function relationship of a plant NCS1 member - Homology modeling and mutagenesis identified residues critical for substrate specificity of PLUTO, a nucleobase transporter from arabidopsis

    KAUST Repository

    Witz, Sandra

    2014-03-12

    Plastidic uracil salvage is essential for plant growth and development. So far, PLUTO, the plastidic nucleobase transporter from Arabidopsis thaliana is the only known uracil importer at the inner plastidic membrane which represents the permeability barrier of this organelle. We present the first homology model of PLUTO, the sole plant NCS1 member from Arabidopsis based on the crystal structure of the benzyl hydantoin transporter MHP1 from Microbacterium liquefaciens and validated by molecular dynamics simulations. Polar side chains of residues Glu-227 and backbones of Val-145, Gly-147 and Thr-425 are proposed to form the binding site for the three PLUTO substrates uracil, adenine and guanine. Mutational analysis and competition studies identified Glu-227 as an important residue for uracil and to a lesser extent for guanine transport. A differential response in substrate transport was apparent with PLUTO double mutants E227Q G147Q and E227Q T425A, both of which most strongly affected adenine transport, and in V145A G147Q, which markedly affected guanine transport. These differences could be explained by docking studies, showing that uracil and guanine exhibit a similar binding mode whereas adenine binds deep into the catalytic pocket of PLUTO. Furthermore, competition studies confirmed these results. The present study defines the molecular determinants for PLUTO substrate binding and demonstrates key differences in structure-function relations between PLUTO and other NCS1 family members. 2014 Witz et al.

  12. The fungicidal and phytotoxic properties of benomyl and PPM in supplemented agar media supporting transgenic arabidopsis plants for a Space Shuttle flight experiment

    Science.gov (United States)

    Paul, A. L.; Semer, C.; Kucharek, T.; Ferl, R. J.

    2001-01-01

    Fungal contamination is a significant problem in the use of sucrose-enriched agar-based media for plant culture, especially in closed habitats such as the Space Shuttle. While a variety of fungicides are commercially available, not all are equal in their effectiveness in inhibiting fungal contamination. In addition, fungicide effectiveness must be weighed against its phytotoxicity and in this case, its influence on transgene expression. In a series of experiments designed to optimize media composition for a recent shuttle mission, the fungicide benomyl and the biocide "Plant Preservative Mixture" (PPM) were evaluated for effectiveness in controlling three common fungal contaminants, as well as their impact on the growth and development of arabidopsis seedlings. Benomyl proved to be an effective inhibitor of all three contaminants in concentrations as low as 2 ppm (parts per million) within the agar medium, and no evidence of phytotoxicity was observed until concentrations exceeded 20 ppm. The biocide mix PPM was effective as a fungicide only at concentrations that had deleterious effects on arabidopsis seedlings. As a result of these findings, a concentration of 3 ppm benomyl was used in the media for experiment PGIM-01 which flew on shuttle Columbia mission STS-93 in July 1999.

  13. The sunflower transcription factor HaHB11 confers tolerance to water deficit and salinity to transgenic Arabidopsis and alfalfa plants.

    Science.gov (United States)

    Cabello, Julieta V; Giacomelli, Jorge I; Gómez, María C; Chan, Raquel L

    2017-09-10

    Homeodomain-leucine zipper (HD-Zip) transcription factors are unique to the plant kingdom; members of subfamily I are known to be involved in abiotic stress responses. HaHB11 belongs to this subfamily and it was previously shown that it is able to confer improved yield and tolerance to flooding via a quiescent strategy. Here we show that HaHB11 expression is induced by ABA, NaCl and water deficit in sunflower seedlings and leaves. Arabidopsis transgenic plants expressing HaHB11, controlled either by its own promoter or by the constitutive 35S CaMV, presented rolled leaves and longer roots than WT when grown under standard conditions. In addition, these plants showed wider stems and more vascular bundles. To deal with drought, HaHB11 transgenic plants closed their stomata faster and lost less water than controls, triggering an enhanced tolerance to such stress condition and also to salinity stress. Concomitantly, ABA-synthesis and sensing related genes were differentially regulated in HaHB11 transgenic plants. Either under long-term salinity stress or mild drought stress, HaHB11 transgenic plants did not exhibit yield penalties. Moreover, alfalfa transgenic plants were generated which also showed enhanced drought tolerance. Altogether, the results indicated that HaHB11 was able to confer drought and salinity tolerance via a complex mechanism which involves morphological, physiological and molecular changes. Copyright © 2016 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

    Kjaersgård, I V; Jespersen, H M; Rasmussen, S K; Welinder, K G

    1997-03-01

    cDNA clones encoding two new Arabidopsis thaliana peroxidases, ATP 1a and ATP 2a, have been identified by searching the Arabidopsis database of expressed sequence tags (dbEST). They represent a novel branch of hitherto uncharacterized plant peroxidases which is only 35% identical in amino acid sequence to the well characterized group of basic plant peroxidases represented by the horseradish (Armoracia rusticana) isoperoxidases HRP C, HRP E5 and the similar Arabidopsis isoperoxidases ATP Ca, ATP Cb, and ATP Ea. However ATP 1a is 87% identical in amino acid sequence to a peroxidase encoded by an mRNA isolated from cotton (Gossypium hirsutum). As cotton and Arabidopsis belong to rather diverse families (Malvaceae and Crucifereae, respectively), in contrast with Arabidopsis and horseradish (both Crucifereae), the high degree of sequence identity indicates that this novel type of peroxidase, albeit of unknown function, is likely to be widespread in plant species. The atp 1 and atp 2 types of cDNA sequences were the most redundant among the 28 different isoperoxidases identified among about 200 peroxidase encoding ESTs. Interestingly, 8 out of totally 38 EST sequences coding for ATP 1 showed three identical nucleotide substitutions. This variant form is designated ATP 1b. Similarly, six out of totally 16 EST sequences coding for ATP 2 showed a number of deletions and nucleotide changes. This variant form is designated ATP 2b. The selected EST clones are full-length and contain coding regions of 993 nucleotides for atp 1a, and 984 nucleotides for atp 2a. These regions show 61% DNA sequence identity. The predicted mature proteins ATP 1a, and ATP 2a are 57% identical in sequence and contain the structurally and functionally important residues, characteristic of the plant peroxidase superfamily. However, they do show two differences of importance to peroxidase catalysis: (1) the asparagine residue linked with the active site distal histidine via hydrogen bonding is absent

  15. The nucleobase cation symporter 1 of Chlamydomonas reinhardtii and that of the evolutionarily distant Arabidopsis thaliana display parallel function and establish a plant-specific solute transport profile.

    Science.gov (United States)

    Schein, Jessica R; Hunt, Kevin A; Minton, Janet A; Schultes, Neil P; Mourad, George S

    2013-09-01

    The single cell alga Chlamydomonas reinhardtii is capable of importing purines as nitrogen sources. An analysis of the annotated C. reinhardtii genome reveals at least three distinct gene families encoding for known nucleobase transporters. In this study the solute transport and binding properties for the lone C. reinhardtii nucleobase cation symporter 1 (CrNCS1) are determined through heterologous expression in Saccharomyces cerevisiae. CrNCS1 acts as a transporter of adenine, guanine, uracil and allantoin, sharing similar - but not identical - solute recognition specificity with the evolutionary distant NCS1 from Arabidopsis thaliana. The results suggest that the solute specificity for plant NCS1 occurred early in plant evolution and are distinct from solute transport specificities of single cell fungal NCS1 proteins. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  16. Database Description - Arabidopsis Phenome Database | LSDB Archive [Life Science Database Archive metadata

    Lifescience Database Archive (English)

    Full Text Available List Contact us Arabidopsis Phenome Database Database Description General information of database Database n... BioResource Center Hiroshi Masuya Database classification Plant databases - Arabidopsis thaliana Organism T...axonomy Name: Arabidopsis thaliana Taxonomy ID: 3702 Database description The Arabidopsis thaliana phenome i...heir effective application. We developed the new Arabidopsis Phenome Database integrating two novel database...seful materials for their experimental research. The other, the “Database of Curated Plant Phenome” focusing

  17. In vitro culture of higher plants as a tool in the propagation of horticultural crops.

    NARCIS (Netherlands)

    Pierik, R.L.M.

    1988-01-01

    In vitro culture of higher plants is the culture, under sterile conditions, of plants, seeds, embryos, organs, explants, tissues, cells and protoplasts on nutrient media. This type of culture has shown spectacular development since 1975, resulting in the production and regeneration of viable

  18. Two Arabidopsis cytochrome P450 monooxygenases, CYP714A1 and CYP714A2, function redundantly in plant development through gibberellin deactivation.

    Science.gov (United States)

    Zhang, Yingying; Zhang, Baichen; Yan, Dawei; Dong, Weixin; Yang, Weibing; Li, Qun; Zeng, Longjun; Wang, Jianjun; Wang, Linyou; Hicks, Leslie M; He, Zuhua

    2011-07-01

    The rice gene ELONGATED UPPERMOST INTERNODE1 (EUI1) encodes a P450 monooxygenase that epoxidizes gibberellins (GAs) in a deactivation reaction. The Arabidopsis genome contains a tandemly duplicated gene pair ELA1 (CYP714A1) and ELA2 (CYP714A2) that encode EUI homologs. In this work, we dissected the functions of the two proteins. ELA1 and ELA2 exhibited overlapping yet distinct gene expression patterns. We showed that while single mutants of ELA1 or ELA2 exhibited no obvious morphological phenotype, simultaneous elimination of ELA1 and ELA2 expression in ELA1-RNAi/ela2 resulted in increased biomass and enlarged organs. By contrast, transgenic plants constitutively expressing either ELA1 or ELA2 were dwarfed, similar to those overexpressing the rice EUI gene. We also discovered that overexpression of ELA1 resulted in a severe dwarf phenotype, while overexpression of ELA2 gave rise to a breeding-favored semi-dwarf phenotype in rice. Consistent with the phenotypes, we found that the ELA1-RNAi/ela2 plants increased amounts of biologically active GAs that were decreased in the internodes of transgenic rice with ELA1 and ELA2 overexpression. In contrast, the precursor GA(12) slightly accumulated in the transgenic rice, and GA(19) highly accumulated in the ELA2 overexpression rice. Taken together, our study strongly suggests that the two Arabidopsis EUI homologs subtly regulate plant growth most likely through catalyzing deactivation of bioactive GAs similar to rice EUI. The two P450s may also function in early stages of the GA biosynthetic pathway. Our results also suggest that ELA2 could be an excellent tool for molecular breeding for high yield potential in cereal crops. © 2011 The Authors. The Plant Journal © 2011 Blackwell Publishing Ltd.

  19. A GRAS-like gene of sunflower (Helianthus annuus L.) alters the gibberellin content and axillary meristem outgrowth in transgenic Arabidopsis plants.

    Science.gov (United States)

    Fambrini, M; Mariotti, L; Parlanti, S; Salvini, M; Pugliesi, C

    2015-11-01

    The GRAS proteins belong to a plant transcriptional regulator family that function in the regulation of plant growth and development. Despite their important roles, in sunflower only one GRAS gene (HaDella1) with the DELLA domain has been reported. Here, we provide a functional characterisation of a GRAS-like gene from Helianthus annuus (Ha-GRASL) lacking the DELLA motif. The Ha-GRASL gene contains an intronless open reading frame of 1,743 bp encoding 580 amino acids. Conserved motifs in the GRAS domain are detected, including VHIID, PFYRE, SAW and two LHR motifs. Within the VHII motif, the P-H-N-D-Q-L residues are entirely maintained. Phylogenetic analysis reveals that Ha-GRASL belongs to the SCARECROW LIKE4/7 (SCL4/7) subfamily of the GRAS consensus tree. Accumulation of Ha-GRASL mRNA at the adaxial boundaries from P6/P7 leaf primordia suggests a role of Ha-GRASL in the initiation of median and basal axillary meristems (AMs) of sunflower. When Ha-GRASL is over-expressed in Arabidopsis wild-type plants, the number of lateral bolts increases differently from untransformed plants. However, Ha-GRASL slightly affects the lateral suppressor (las-4-) mutation. Therefore, we hypothesise that Ha-GRASL and LAS are not functionally equivalent. The over-expression of Ha-GRASL reduces metabolic flow of gibberellins (GAs) in Arabidopsis and this modification could be relevant in AM development. Phylogenetic analysis includes LAS and SCL4/7 in the same major clade, suggesting a more recent separation of these genes with respect to other GRAS members. We propose that some features of their ancestor, as well as AM initiation and outgrowth, are partially retained in both LAS and SCL4/7. © 2015 German Botanical Society and The Royal Botanical Society of the Netherlands.

  20. Bioinformatics analysis of the predicted polyprenol reductase genes in higher plants

    Science.gov (United States)

    Basyuni, M.; Wati, R.

    2018-03-01

    The present study evaluates the bioinformatics methods to analyze twenty-four predicted polyprenol reductase genes from higher plants on GenBank as well as predicted the structure, composition, similarity, subcellular localization, and phylogenetic. The physicochemical properties of plant polyprenol showed diversity among the observed genes. The percentage of the secondary structure of plant polyprenol genes followed the ratio order of α helix > random coil > extended chain structure. The values of chloroplast but not signal peptide were too low, indicated that few chloroplast transit peptide in plant polyprenol reductase genes. The possibility of the potential transit peptide showed variation among the plant polyprenol reductase, suggested the importance of understanding the variety of peptide components of plant polyprenol genes. To clarify this finding, a phylogenetic tree was drawn. The phylogenetic tree shows several branches in the tree, suggested that plant polyprenol reductase genes grouped into divergent clusters in the tree.

  1. FRIENDLY regulates mitochondrial distribution, fusion, and quality control in Arabidopsis.

    Science.gov (United States)

    El Zawily, Amr M; Schwarzländer, Markus; Finkemeier, Iris; Johnston, Iain G; Benamar, Abdelilah; Cao, Yongguo; Gissot, Clémence; Meyer, Andreas J; Wilson, Ken; Datla, Raju; Macherel, David; Jones, Nick S; Logan, David C

    2014-10-01

    Mitochondria are defining components of most eukaryotes. However, higher plant mitochondria differ biochemically, morphologically, and dynamically from those in other eukaryotes. FRIENDLY, a member of the CLUSTERED MITOCHONDRIA superfamily, is conserved among eukaryotes and is required for correct distribution of mitochondria within the cell. We sought to understand how disruption of FRIENDLY function in Arabidopsis (Arabidopsis thaliana) leads to mitochondrial clustering and the effects of this aberrant chondriome on cell and whole-plant physiology. We present evidence for a role of FRIENDLY in mediating intermitochondrial association, which is a necessary prelude to mitochondrial fusion. We demonstrate that disruption of mitochondrial association, motility, and chondriome structure in friendly affects mitochondrial quality control and leads to mitochondrial stress, cell death, and strong growth phenotypes. © 2014 American Society of Plant Biologists. All Rights Reserved.

  2. Identification of reference genes for quantitative expression analysis using large-scale RNA-seq data of Arabidopsis thaliana and model crop plants.

    Science.gov (United States)

    Kudo, Toru; Sasaki, Yohei; Terashima, Shin; Matsuda-Imai, Noriko; Takano, Tomoyuki; Saito, Misa; Kanno, Maasa; Ozaki, Soichi; Suwabe, Keita; Suzuki, Go; Watanabe, Masao; Matsuoka, Makoto; Takayama, Seiji; Yano, Kentaro

    2016-10-13

    In quantitative gene expression analysis, normalization using a reference gene as an internal control is frequently performed for appropriate interpretation of the results. Efforts have been devoted to exploring superior novel reference genes using microarray transcriptomic data and to evaluating commonly used reference genes by targeting analysis. However, because the number of specifically detectable genes is totally dependent on probe design in the microarray analysis, exploration using microarray data may miss some of the best choices for the reference genes. Recently emerging RNA sequencing (RNA-seq) provides an ideal resource for comprehensive exploration of reference genes since this method is capable of detecting all expressed genes, in principle including even unknown genes. We report the results of a comprehensive exploration of reference genes using public RNA-seq data from plants such as Arabidopsis thaliana (Arabidopsis), Glycine max (soybean), Solanum lycopersicum (tomato) and Oryza sativa (rice). To select reference genes suitable for the broadest experimental conditions possible, candidates were surveyed by the following four steps: (1) evaluation of the basal expression level of each gene in each experiment; (2) evaluation of the expression stability of each gene in each experiment; (3) evaluation of the expression stability of each gene across the experiments; and (4) selection of top-ranked genes, after ranking according to the number of experiments in which the gene was expressed stably. Employing this procedure, 13, 10, 12 and 21 top candidates for reference genes were proposed in Arabidopsis, soybean, tomato and rice, respectively. Microarray expression data confirmed that the expression of the proposed reference genes under broad experimental conditions was more stable than that of commonly used reference genes. These novel reference genes will be useful for analyzing gene expression profiles across experiments carried out under various

  3. Efficient Plastid Transformation in Arabidopsis.

    Science.gov (United States)

    Yu, Qiguo; Lutz, Kerry Ann; Maliga, Pal

    2017-09-01

    Plastid transformation is routine in tobacco ( Nicotiana tabacum ) but 100-fold less frequent in Arabidopsis ( Arabidopsis thaliana ), preventing its use in plastid biology. A recent study revealed that null mutations in ACC2 , encoding a plastid-targeted acetyl-coenzyme A carboxylase, cause hypersensitivity to spectinomycin. We hypothesized that plastid transformation efficiency should increase in the acc2 background, because when ACC2 is absent, fatty acid biosynthesis becomes dependent on translation of the plastid-encoded ACC β-carboxylase subunit. We bombarded ACC2 -defective Arabidopsis leaves with a vector carrying a selectable spectinomycin resistance ( aadA ) gene and gfp , encoding the green fluorescence protein GFP. Spectinomycin-resistant clones were identified as green cell clusters on a spectinomycin medium. Plastid transformation was confirmed by GFP accumulation from the second open reading frame of a polycistronic messenger RNA, which would not be translated in the cytoplasm. We obtained one to two plastid transformation events per bombarded sample in spectinomycin-hypersensitive Slavice and Columbia acc2 knockout backgrounds, an approximately 100-fold enhanced plastid transformation frequency. Slavice and Columbia are accessions in which plant regeneration is uncharacterized or difficult to obtain. A practical system for Arabidopsis plastid transformation will be obtained by creating an ACC2 null background in a regenerable Arabidopsis accession. The recognition that the duplicated ACCase in Arabidopsis is an impediment to plastid transformation provides a rational template to implement plastid transformation in related recalcitrant crops. © 2017 American Society of Plant Biologists. All Rights Reserved.

  4. Arabidopsis NATA1 Acetylates Putrescine and Decreases Defense-Related Hydrogen Peroxide Accumulation1[OPEN

    Science.gov (United States)

    Preuss, Aileen S.

    2016-01-01

    Biosynthesis of the polyamines putrescine, spermidine, and spermine is induced in response to pathogen infection of plants. Putrescine, which is produced from Arg, serves as a metabolic precursor for longer polyamines, including spermidine and spermine. Polyamine acetylation, which has important regulatory functions in mammalian cells, has been observed in several plant species. Here we show that Arabidopsis (Arabidopsis thaliana) N-ACETYLTRANSFERASE ACTIVITY1 (NATA1) catalyzes acetylation of putrescine to N-acetylputrescine and thereby competes with spermidine synthase for a common substrate. NATA1 expression is strongly induced by the plant defense signaling molecule jasmonic acid and coronatine, an effector molecule produced by DC3000, a Pseudomonas syringae strain that initiates a virulent infection in Arabidopsis ecotype Columbia-0. DC3000 growth is reduced in nata1 mutant Arabidopsis, suggesting a role for NATA1-mediated putrescine acetylation in suppressing antimicrobial defenses. During infection by P. syringae and other plant pathogens, polyamine oxidases use spermidine and spermine as substrates for the production of defense-related H2O2. Compared to wild-type Columbia-0 Arabidopsis, the response of nata1mutants to P. syringae infection includes reduced accumulation of acetylputrescine, greater abundance of nonacetylated polyamines, elevated H2O2 production by polyamine oxidases, and higher expression of genes related to pathogen defense. Together, these results are consistent with a model whereby P. syringae growth is improved in a targeted manner through coronatine-induced putrescine acetylation by NATA1. PMID:27208290

  5. Disruption of the Arabidopsis CGI-58 homologue produces Chanarin–Dorfman-like lipid droplet accumulation in plants

    OpenAIRE

    James, Christopher N.; Horn, Patrick J.; Case, Charlene R.; Gidda, Satinder K.; Zhang, Daiyuan; Mullen, Robert T.; Dyer, John M.; Anderson, Richard G. W.; Chapman, Kent D.

    2010-01-01

    CGI-58 is the defective gene in the human neutral lipid storage disease called Chanarin-Dorfman syndrome. This disorder causes intracellular lipid droplets to accumulate in nonadipose tissues, such as skin and blood cells. Here, disruption of the homologous CGI-58 gene in Arabidopsis thaliana resulted in the accumulation of neutral lipid droplets in mature leaves. Mass spectroscopy of isolated lipid droplets from cgi-58 loss-of-function mutants showed they contain triacylglycerols with common...

  6. Acute exposure to UV-B sensitizes cucumber, tomato, and Arabidopsis plants to photooxidative stress by inhibiting thermal energy dissipation and antioxidant defense

    International Nuclear Information System (INIS)

    Moon, Yu-Ran; Lee, Min-Hee; Chung, Byung-Yeoup; Kim, Jin-Hong; Tovuu, Altanzaya; Lee, Choon-Hwan; Park, Youn-Il

    2011-01-01

    The purpose of this study was to characterize a change in Non-photochemical quenching (NPQ) upon exposure to ultraviolet-B (UV-B), the xanthophyll cycle-dependent and -independent NPQs were compared in Cucumis sativus, Lycopersicum esculentum, and Arabidopsis thaliana leaves. The xanthophyll cycle-dependent NPQ was dramatically but reversibly suppressed by UV-B radiation. This suppression was correlated more strongly with a marked decrease in photosynthetic electron transport rather than changes in xanthophyll cycle enzymes such as violaxanthin de-epoxidase and zeaxanthin epoxidase. Accordingly, the UV-B-induced suppression of NPQ cannot be attributed to changes in expressions of violaxanthin de-epoxidase (VDE) and zeaxanthin epoxidase (ZEP). However, suppression of the xanthophyll cycle-dependent NPQ could only account for the 77 K fluorescence emission spectra of thylakoid membranes and the increased level of 1 O 2 production, but not for the decreased levels of hydroxyl radical O 2 - production and H 2 O 2 scavenging. These results suggest that a gradual reduction of H 2 O 2 scavenging activity as well as a transient and reversible suppression of thermal energy dissipation may contribute differentially to increased photooxidative damages in cucumber, tomato, and Arabidopsis plants after acute exposure to UV-B radiation. (author)

  7. The ways of controlling microbiota of the higher plant link in LSS

    Science.gov (United States)

    Tirranen, L. S.; Gitelson, I. I.

    The ways of controlling microbiota of the higher plant link have been considered, as the sterile plant growth in closed ecological human life support systems is impossible. One of the ways of controlling the link microbial community - building sterile intrasystem barriers between the system links - is problematic and dangerous. An accidental breach of microorganisms through the barrier can lead to disastrous consequences - either unrestrained reproduction of microbes including pathogenic and conditionally pathogenic species or, on the contrary, elimination of species most valuable for the given microbial community. Another way of control is maintaining suitable conditions for human and plant habitat, creating some constructive system properties directed at microbial exchange weakening. The use of catalytic furnace for oxidizing organic impurities in system atmosphere, UV processing of air and plants in the phytotron before and in the beginning of the experiments promoted decrease of microorganism amount in the link. To restrict the distribution of microorganisms of the higher plant link in other system links the module for yield processing being under constant suction was isolated. To prevent the introduction of microorganisms into the system we applied the UV processing of all objects transferred to the system and continuous atmosphere overpressure inside the system. It is important to detect the ultimate amount of microorganism indicator groups in the higher plant link biocenosis. It would indicate the microbial pollution of the link and be the signal for regulation of its microbial population or processing technologies in the studied objects. There were two 4-month experiments with the "human - higher plants" closed ecosystem carried out. There was no progressive deterioration for plants, decrease of wheat yield to zero and rapid growth of microorganisms in the higher plant link after making all listed arrangements. Microbiological analyses of the studied

  8. GOLDEN2-LIKE transcription factors coordinate the tolerance to Cucumber mosaic virus in Arabidopsis

    Energy Technology Data Exchange (ETDEWEB)

    Han, Xue-Ying; Li, Peng-Xu; Zou, Li-Juan; Tan, Wen-rong; Zheng, Ting; Zhang, Da-Wei, E-mail: yuanmiao1892@163.com; Lin, Hong-Hui, E-mail: hhlin@scu.edu.cn

    2016-09-02

    Arabidopsis thaliana GOLDEN2-LIKE (GLKs) transcription factors play important roles in regulation of photosynthesis-associated nuclear genes, as well as participate in chloroplast development. However, the involvement of GLKs in plants resistance to virus remains largely unknown. Here, the relationship between GLKs and Cucumber mosaic virus (CMV) stress response was investigated. Our results showed that the Arabidopsis glk1glk2 double-mutant was more susceptible to CMV infection and suffered more serious damages (such as higher oxidative damages, more compromised in PSII photochemistry and more reactive oxygen species accumulation) when compared with the wild-type plants. Interestingly, there was little difference between single mutant (glk1 or glk2) and wild-type plants in response to CMV infection, suggesting GLK1 and GLK2 might function redundant in virus resistance in Arabidopsis. Furthermore, the induction of antioxidant system and defense-associated genes expression in the double mutant were inhibited when compared with single mutant or wild-type plants after CMV infection. Further evidences showed that salicylic acid (SA) and jasmonic acid (JA) might be involved in GLKs-mediated virus resistance, as SA or JA level and synthesis-related genes transcription were impaired in glk1glk2 mutant. Taken together, our results indicated that GLKs played a positively role in virus resistance in Arabidopsis. - Highlights: • GLKs play a positive role in CMV resistance in Arabidopsis. • Defective of GLKs suffered more ROS accumulation. • Arabidopsis lacking GLKs have damaged photosynthesis. • Arabidopsis lacking GLKs show low SA and JA accumulation.

  9. GOLDEN2-LIKE transcription factors coordinate the tolerance to Cucumber mosaic virus in Arabidopsis

    International Nuclear Information System (INIS)

    Han, Xue-Ying; Li, Peng-Xu; Zou, Li-Juan; Tan, Wen-rong; Zheng, Ting; Zhang, Da-Wei; Lin, Hong-Hui

    2016-01-01

    Arabidopsis thaliana GOLDEN2-LIKE (GLKs) transcription factors play important roles in regulation of photosynthesis-associated nuclear genes, as well as participate in chloroplast development. However, the involvement of GLKs in plants resistance to virus remains largely unknown. Here, the relationship between GLKs and Cucumber mosaic virus (CMV) stress response was investigated. Our results showed that the Arabidopsis glk1glk2 double-mutant was more susceptible to CMV infection and suffered more serious damages (such as higher oxidative damages, more compromised in PSII photochemistry and more reactive oxygen species accumulation) when compared with the wild-type plants. Interestingly, there was little difference between single mutant (glk1 or glk2) and wild-type plants in response to CMV infection, suggesting GLK1 and GLK2 might function redundant in virus resistance in Arabidopsis. Furthermore, the induction of antioxidant system and defense-associated genes expression in the double mutant were inhibited when compared with single mutant or wild-type plants after CMV infection. Further evidences showed that salicylic acid (SA) and jasmonic acid (JA) might be involved in GLKs-mediated virus resistance, as SA or JA level and synthesis-related genes transcription were impaired in glk1glk2 mutant. Taken together, our results indicated that GLKs played a positively role in virus resistance in Arabidopsis. - Highlights: • GLKs play a positive role in CMV resistance in Arabidopsis. • Defective of GLKs suffered more ROS accumulation. • Arabidopsis lacking GLKs have damaged photosynthesis. • Arabidopsis lacking GLKs show low SA and JA accumulation.

  10. PsbS-specific zeaxanthin-independent changes in fluorescence emission spectrum as a signature of energy-dependent non-photochemical quenching in higher plants.

    Science.gov (United States)

    Zulfugarov, Ismayil S; Tovuu, Altanzaya; Dogsom, Bolormaa; Lee, Chung Yeol; Lee, Choon-Hwan

    2010-05-01

    The PsbS protein of photosystem II is necessary for the development of energy-dependent quenching of chlorophyll (Chl) fluorescence (qE), and PsbS-deficient Arabidopsis plant leaves failed to show qE-specific changes in the steady-state 77 K fluorescence emission spectra observed in wild-type leaves. The difference spectrum between the quenched and un-quenched states showed a negative peak at 682 nm. Although the level of qE development in the zeaxanthin-less npq1-2 mutant plants, which lacked violaxanthin de-epoxidase enzyme, was only half that of wild type, there were no noticeable changes in this qE-dependent difference spectrum. This zeaxanthin-independent DeltaF682 signal was not dependent on state transition, and the signal was not due to photobleaching of pigments either. These results suggest that DeltaF682 signal is formed due to PsbS-specific conformational changes in the quenching site of qE and is a new signature of qE generation in higher plants.

  11. Three pectin methylesterase inhibitors protect cell wall integrity for arabidopsis immunity to Botrytis

    DEFF Research Database (Denmark)

    Lionetti, Vincenzo; Fabri, Eleonora; Caroli, Monica De

    2017-01-01

    to the control plants. A higher stimulation of the fungal oxalic acid biosynthetic pathway also can contribute to the higher susceptibility of pmei mutants. The lack of PMEI expression does not affect hemicellulose strengthening, callose deposition, and the synthesis of structural defense proteins, proposed...... is posttranscriptionally regulated by endogenous protein inhibitors (PMEIs). Here, AtPMEI10, AtPMEI11, and AtPMEI12 are identified as functional PMEIs induced in Arabidopsis (Arabidopsis thaliana) during B. cinerea infection. AtPMEI expression is strictly regulated by jasmonic acid and ethylene signaling, while only At...

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

    Directory of Open Access Journals (Sweden)

    Silué, S.

    2011-01-01

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

  13. Arabidopsis: an adequate model for dicot root systems?

    Directory of Open Access Journals (Sweden)

    Richard W Zobel

    2016-02-01

    Full Text Available The Arabidopsis root system is frequently considered to have only three classes of root: primary, lateral, and adventitious. Research with other plant species has suggested up to 8 different developmental/functional classes of root for a given plant root system. If Arabidopsis has only three classes of root, it may not be an adequate model for eudicot plant root systems. Recent research, however, can be interpreted to suggest that pre-flowering Arabidopsis does have at least five (5 of these classes of root. This then suggests that Arabidopsis root research can be considered an adequate model for eudicot plant root systems.

  14. A database of PCR primers for the chloroplast genomes of higher plants

    Science.gov (United States)

    Heinze, Berthold

    2007-01-01

    Background Chloroplast genomes evolve slowly and many primers for PCR amplification and analysis of chloroplast sequences can be used across a wide array of genera. In some cases 'universal' primers have been designed for the purpose of working across species boundaries. However, the essential information on these primer sequences is scattered throughout the literature. Results A database is presented here which assembles published primer information for chloroplast DNA. Additional primers were designed to fill gaps where little or no primer information could be found. Amplicons are either the genes themselves (typically useful in studies of sequence variation in higher-order phylogeny) or they are spacers, introns, and intergenic regions (for studies of phylogeographic patterns within and among species). The current list of 'generic' primers consists of more than 700 sequences. Wherever possible, we give the locations of the primers in the thirteen fully sequenced chloroplast genomes (Nicotiana tabacum, Atropa belladonna, Spinacia oleracea, Arabidopsis thaliana, Populus trichocarpa, Oryza sativa, Pinus thunbergii, Marchantia polymorpha, Zea mays, Oenothera elata, Acorus calamus, Eucalyptus globulus, Medicago trunculata). Conclusion The database described here is designed to serve as a resource for researchers who are venturing into the study of poorly described chloroplast genomes, whether for large- or small-scale DNA sequencing projects, to study molecular variation or to investigate chloroplast evolution. PMID:17326828

  15. A database of PCR primers for the chloroplast genomes of higher plants

    Directory of Open Access Journals (Sweden)

    Heinze Berthold

    2007-02-01

    Full Text Available Abstract Background Chloroplast genomes evolve slowly and many primers for PCR amplification and analysis of chloroplast sequences can be used across a wide array of genera. In some cases 'universal' primers have been designed for the purpose of working across species boundaries. However, the essential information on these primer sequences is scattered throughout the literature. Results A database is presented here which assembles published primer information for chloroplast DNA. Additional primers were designed to fill gaps where little or no primer information could be found. Amplicons are either the genes themselves (typically useful in studies of sequence variation in higher-order phylogeny or they are spacers, introns, and intergenic regions (for studies of phylogeographic patterns within and among species. The current list of 'generic' primers consists of more than 700 sequences. Wherever possible, we give the locations of the primers in the thirteen fully sequenced chloroplast genomes (Nicotiana tabacum, Atropa belladonna, Spinacia oleracea, Arabidopsis thaliana, Populus trichocarpa, Oryza sativa, Pinus thunbergii, Marchantia polymorpha, Zea mays, Oenothera elata, Acorus calamus, Eucalyptus globulus, Medicago trunculata. Conclusion The database described here is designed to serve as a resource for researchers who are venturing into the study of poorly described chloroplast genomes, whether for large- or small-scale DNA sequencing projects, to study molecular variation or to investigate chloroplast evolution.

  16. AtMRP1 gene of Arabidopsis encodes a glutathione S-conjugate pump: isolation and functional definition of a plant ATP-binding cassette transporter gene.

    Science.gov (United States)

    Lu, Y P; Li, Z S; Rea, P A

    1997-07-22

    Because plants produce cytotoxic compounds to which they, themselves, are susceptible and are exposed to exogenous toxins (microbial products, allelochemicals, and agrochemicals), cell survival is contingent on mechanisms for detoxifying these agents. One detoxification mechanism is the glutathione S-transferase-catalyzed glutathionation of the toxin, or an activated derivative, and transport of the conjugate out of the cytosol. We show here that a transporter responsible for the removal of glutathione S-conjugates from the cytosol, a specific Mg2+-ATPase, is encoded by the AtMRP1 gene of Arabidopsis thaliana. The sequence of AtMRP1 and the transport capabilities of membranes prepared from yeast cells transformed with plasmid-borne AtMRP1 demonstrate that this gene encodes an ATP-binding cassette transporter competent in the transport of glutathione S-conjugates of xenobiotics and endogenous substances, including herbicides and anthocyanins.

  17. An efficient and reproducible protocol for the production of salt tolerant transgenic wheat plants expressing the Arabidopsis AtNHX1 gene.

    Science.gov (United States)

    Moghaieb, Reda E A; Sharaf, Ahmed N; Soliman, Mohamed H; El-Arabi, Nagwa I; Momtaz, Osama A

    2014-01-01

    We present an efficient method for the production of transgenic salt tolerant hexaploid wheat plants expressing the Arabidopsis AtNHX1 gene. Wheat mature zygotic embryos were isolated from two hexaploid bread wheat (Triticum aestivum) cultivars (namely: Gemmeiza 9 and Gemmeiza 10) and were transformed with the A. tumefaciens LBA4404 harboring the pBI-121 vector containing the AtNHX1 gene. Transgenic wheat lines that express the gus intron was obtained and used as control. The results confirmed that npt-II gene could be transmitted and expressed in the T2 following 3:1 Mendelian segregation while the control plant couldn't. The data indicate that, the AtNHX1 gene was integrated in a stable manner into the wheat genome and the corresponding transcripts were expressed. The transformation efficiency was 5.7 and 7.5% for cultivars Gemmeiza 10 and Gemmeiza 9, respectively. A greenhouse experiment was conducted to investigate the effect of AtNHX1 gene in wheat salt tolerance. The transgenic wheat lines could maintain high growth rate under salt stress condition (350 mM NaCl) while the control plant couldn't. The results confirmed that Na(+)/H(+) antiporter gene AtNHX1 increased salt tolerance by increasing Na(+) accumulation and keeping K+/Na(+) balance. Thus, transgenic plants showed high tolerance to salt stress and can be considered as a new genetic resource in breeding programs.

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

    Directory of Open Access Journals (Sweden)

    Gutiérrez Rodrigo A

    2008-09-01

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

  19. Abiotic stress leads to somatic and heritable changes in homologous recombination frequency, point mutation frequency and microsatellite stability in Arabidopsis plants

    International Nuclear Information System (INIS)

    Yao Youli; Kovalchuk, Igor

    2011-01-01

    In earlier studies, we showed that abiotic stresses, such as ionizing radiation, heavy metals, temperature and water, trigger an increase in homologous recombination frequency (HRF). We also demonstrated that many of these stresses led to inheritance of high-frequency homologous recombination, HRF. Although an increase in recombination frequency is an important indicator of genome rearrangements, it only represents a minor portion of possible stress-induced mutations. Here, we analyzed the influence of heat, cold, drought, flood and UVC abiotic stresses on two major types of mutations in the genome, point mutations and small deletions/insertions. We used two transgenic lines of Arabidopsis thaliana, one allowing an analysis of reversions in a stop codon-containing inactivated β-glucuronidase transgene and another one allowing an analysis of repeat stability in a microsatellite-interrupted β-glucuronidase transgene. The transgenic Arabidopsis line carrying the β-glucuronidase-based homologous recombination substrate was used as a positive control. We showed that the majority of stresses increased the frequency of point mutations, homologous recombination and microsatellite instability in somatic cells, with the frequency of homologous recombination being affected the most. The analysis of transgenerational changes showed an increase in HRF to be the most prominent effect observed in progeny. Significant changes in recombination frequency were observed upon exposure to all types of stress except drought, whereas changes in microsatellite instability were observed upon exposure to UVC, heat and cold. The frequency of point mutations in the progeny of stress-exposed plants was the least affected; an increase in mutation frequency was observed only in the progeny of plants exposed to UVC. We thus conclude that transgenerational changes in genome stability in response to stress primarily involve an increase in recombination frequency.

  20. The Arabidopsis Halophytic Relative Thellungiella halophila Tolerates Nitrogen-Limiting Conditions by Maintaining Growth, Nitrogen Uptake, and Assimilation1[W][OA

    Science.gov (United States)

    Kant, Surya; Bi, Yong-Mei; Weretilnyk, Elizabeth; Barak, Simon; Rothstein, Steven J.

    2008-01-01

    A comprehensive knowledge of mechanisms regulating nitrogen (N) use efficiency is required to reduce excessive input of N fertilizers while maintaining acceptable crop yields under limited N supply. Studying plant species that are naturally adapted to low N conditions could facilitate the identification of novel regulatory genes conferring better N use efficiency. Here, we show that Thellungiella halophila, a halophytic relative of Arabidopsis (Arabidopsis thaliana), grows better than Arabidopsis under moderate (1 mm nitrate) and severe (0.4 mm nitrate) N-limiting conditions. Thellungiella exhibited a lower carbon to N ratio than Arabidopsis under N limitation, which was due to Thellungiella plants possessing higher N content, total amino acids, total soluble protein, and lower starch content compared with Arabidopsis. Furthermore, Thellungiella had higher amounts of several metabolites, such as soluble sugars and organic acids, under N-sufficient conditions (4 mm nitrate). Nitrate reductase activity and NR2 gene expression in Thellungiella displayed less of a reduction in response to N limitation than in Arabidopsis. Thellungiella shoot GS1 expression was more induced by low N than in Arabidopsis, while in roots, Thellungiella GS2 expression was maintained under N limitation but was decreased in Arabidopsis. Up-regulation of NRT2.1 and NRT3.1 expression was higher and repression of NRT1.1 was lower in Thellungiella roots under N-limiting conditions compared with Arabidopsis. Differential transporter gene expression was correlated with higher nitrate influx in Thellungiella at low 15NO3− supply. Taken together, our results suggest that Thellungiella is tolerant to N-limited conditions and could act as a model system to unravel the mechanisms for low N tolerance. PMID:18467466

  1. Aquatic food production modules in bioregenerative life support systems based on higher plants

    Science.gov (United States)

    Bluem, V.; Paris, F.

    Most bioregenerative life support systems (BLSS) are based on gravitropic higher plants which exhibit growth and seed generation disturbances in microgravity. Even when used for a lunar or martian base the reduced gravity may induce a decreased productivity in comparison to Earth. Therefore, the implementation of aquatic biomass production modules in higher plant and/or hybrid BLSS may compensate for this and offer, in addition, the possibility to produce animal protein for human nutrition. It was shown on the SLS-89 and SLS-90 space shuttle missions with the C.E.B.A.S.-MINI MODULE that the edible non gravitropic rootless higher aquatic plant Ceratophyllum demeresum exhibits an undisturbed high biomass production rate in space and that the teleost fish species, Xiphophorus helleri, adapts rapidly to space conditions without loss of its normal reproductive functions. Based on these findings a series of ground-based aquatic food production systems were developed which are disposed for utilization in space. These are plant production bioreactors for the species mentioned above and another suitable candidate, the lemnacean (duckweed) species, Wolffia arrhiza. Moreover, combined intensive aquaculture systems with a closed food loop between herbivorous fishes and aquatic and land plants are being developed which may be suitable for integration into a BLSS of higher complexity.

  2. Overexpression of WsSGTL1 Gene of Withania somnifera Enhances Salt Tolerance, Heat Tolerance and Cold Acclimation Ability in Transgenic Arabidopsis Plants

    Science.gov (United States)

    Mishra, Manoj K.; Chaturvedi, Pankaj; Singh, Ruchi; Singh, Gaurav; Sharma, Lokendra K.; Pandey, Vibha; Kumari, Nishi; Misra, Pratibha

    2013-01-01

    Background Sterol glycosyltrnasferases (SGT) are enzymes that glycosylate sterols which play important role in plant adaptation to stress and are medicinally important in plants like Withania somnifera. The present study aims to find the role of WsSGTL1 which is a sterol glycosyltransferase from W. somnifera, in plant’s adaptation to abiotic stress. Methodology The WsSGTL1 gene was transformed in Arabidopsis thaliana through Agrobacterium mediated transformation, using the binary vector pBI121, by floral dip method. The phenotypic and physiological parameters like germination, root length, shoot weight, relative electrolyte conductivity, MDA content, SOD levels, relative electrolyte leakage and chlorophyll measurements were compared between transgenic and wild type Arabidopsis plants under different abiotic stresses - salt, heat and cold. Biochemical analysis was done by HPLC-TLC and radiolabelled enzyme assay. The promoter of the WsSGTL1 gene was cloned by using Genome Walker kit (Clontech, USA) and the 3D structures were predicted by using Discovery Studio Ver. 2.5. Results The WsSGTL1 transgenic plants were confirmed to be single copy by Southern and homozygous by segregation analysis. As compared to WT, the transgenic plants showed better germination, salt tolerance, heat and cold tolerance. The level of the transgene WsSGTL1 was elevated in heat, cold and salt stress along with other marker genes such as HSP70, HSP90, RD29, SOS3 and LEA4-5. Biochemical analysis showed the formation of sterol glycosides and increase in enzyme activity. When the promoter of WsSGTL1 gene was cloned from W. somnifera and sequenced, it contained stress responsive elements. Bioinformatics analysis of the 3D structure of the WsSGTL1 protein showed functional similarity with sterol glycosyltransferase AtSGT of A. thaliana. Conclusions Transformation of WsSGTL1 gene in A. thaliana conferred abiotic stress tolerance. The promoter of the gene in W.somnifera was found to have stress

  3. Reference: 306 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available of the endoreduplication cycle in Arabidopsis requires a plant homologue of archaeal DNA topoisomerase (topo) VI. To further understa...nd how DNA is endoreduplicated and how this process is r

  4. Which plant trait explains the variations in relative growth rate and its response to elevated carbon dioxide concentration among Arabidopsis thaliana ecotypes derived from a variety of habitats?

    Science.gov (United States)

    Oguchi, Riichi; Ozaki, Hiroshi; Hanada, Kousuke; Hikosaka, Kouki

    2016-03-01

    Elevated atmospheric carbon dioxide (CO2) concentration ([CO2]) enhances plant growth, but this enhancement varies considerably. It is still uncertain which plant traits are quantitatively related to the variation in plant growth. To identify the traits responsible, we developed a growth analysis model that included primary parameters associated with morphology, nitrogen (N) use, and leaf and root activities. We analysed the vegetative growth of 44 ecotypes of Arabidopsis thaliana L. grown at ambient and elevated [CO2] (800 μmol mol(-1)). The 44 ecotypes were selected such that they were derived from various altitudes and latitudes. Relative growth rate (RGR; growth rate per unit plant mass) and its response to [CO2] varied by 1.5- and 1.7-fold among ecotypes, respectively. The variation in RGR at both [CO2]s was mainly explained by the variation in leaf N productivity (LNP; growth rate per leaf N),which was strongly related to photosynthetic N use efficiency (PNUE). The variation in the response of RGR to [CO2] was also explained by the variation in the response of LNP to [CO2]. Genomic analyses indicated that there was no phylogenetic constraint on inter-ecotype variation in the CO2 response of RGR or LNP. We conclude that the significant variation in plant growth and its response to [CO2] among ecotypes reflects the variation in N use for photosynthesis among ecotypes, and that the response of PNUE to CO2 is an important target for predicting and/or breeding plants that have high growth rates at elevated [CO2].

  5. Responses of transgenic Arabidopsis plants and recombinant yeast cells expressing a novel durum wheat manganese superoxide dismutase TdMnSOD to various abiotic stresses.

    Science.gov (United States)

    Kaouthar, Feki; Ameny, Farhat-Khemakhem; Yosra, Kamoun; Walid, Saibi; Ali, Gargouri; Faiçal, Brini

    2016-07-01

    In plant cells, the manganese superoxide dismutase (Mn-SOD) plays an elusive role in the response to oxidative stress. In this study, we describe the isolation and functional characterization of a novel Mn-SOD from durum wheat (Triticum turgidum L. subsp. Durum), named TdMnSOD. Molecular phylogeny analysis showed that the durum TdMnSOD exhibited high amino acids sequence identity with other Mn-SOD plants. The three-dimensional structure showed that TdMnSOD forms a homotetramer and each subunit is composed of a predominantly α-helical N-terminal domain and a mixed α/β C-terminal domain. TdMnSOD gene expression analysis showed that this gene was induced by various abiotic stresses in durum wheat. The expression of TdMnSOD enhances tolerance of the transformed yeast cells to salt, osmotic, cold and H2O2-induced oxidative stresses. Moreover, the analysis of TdMnSOD transgenic Arabidopsis plants subjected to different environmental stresses revealed low H2O2 and high proline levels as compared to the wild-type plants. Compared with the non-transformed plants, an increase in the total SOD and two other antioxidant enzyme activities including catalase (CAT) and peroxidases (POD) was observed in the three transgenic lines subjected to abiotic stress. Taken together, these data provide evidence for the involvement of durum wheat TdMnSOD in tolerance to multiple abiotic stresses in crop plants. Copyright © 2016 Elsevier GmbH. All rights reserved.

  6. Co-localisation studies of Arabidopsis SR splicing factors reveal different types of speckles in plant cell nuclei

    International Nuclear Information System (INIS)

    Lorkovic, Zdravko J.; Hilscher, Julia; Barta, Andrea

    2008-01-01

    SR proteins are multidomain splicing factors which are important for spliceosome assembly and for regulation of alternative splicing. In mammalian nuclei these proteins localise to speckles from where they are recruited to transcription sites. By using fluorescent protein fusion technology and different experimental approaches it has been shown that Arabidopsis SR proteins, in addition to diffuse nucleoplasmic staining, localise into an irregular nucleoplasmic network resembling speckles in mammalian cells. As Arabidopsis SR proteins fall into seven conserved sub-families we investigated co-localisation of members of the different sub-families in transiently transformed tobacco protoplast. Here we demonstrate the new finding that members of different SR protein sub-families localise into distinct populations of nuclear speckles with no, partial or complete co-localisation. This is particularly interesting as we also show that these proteins do interact in a yeast two-hybrid assay as well as in pull-down and in co-immunopreciptiation assays. Our data raise the interesting possibility that SR proteins are partitioned into distinct populations of nuclear speckles to allow a more specific recruitment to the transcription/pre-mRNA processing sites of particular genes depending on cell type and developmental stage

  7. Research and higher education background of the Paks Nuclear Power Plant, Hungary. Past and present

    International Nuclear Information System (INIS)

    Csom, Gy.

    2002-01-01

    The connection of the Paks Nuclear Power Plant, Hungary, with research and development as well as with higher education is discussed. The main research areas include reactor physics, thermohydraulics, radiochemistry and radiochemical analysis, electronics and nuclear instruments, computers, materials science. The evolution of relations with higher education in Hungary and the PNPP is presented, before and after the installation of the various units. (R.P.)

  8. Role of algae and higher aquatic plants in decontamination of cyanide-containing waters

    International Nuclear Information System (INIS)

    Timofeeva, S.S.; Kraeva, V.Z.; Men'shikova, O.A.

    1986-01-01

    Cyanide compounds and especially free cyanides stand out among components of wastewaters of hydrometallurgy, electroforming, and other such enterprises with respect to toxicity and danger for man and fauna of water bodies. In this article data on a study of the regularities of decontamination of cyanide-containing wastewaters by hydrophytes are given, the mechanisms of this process are examined, and the results of testing the hydrobotanical method of treating wastewaters of a goldrecovery plant are examined. The experiments were carried out with hydrophytes from the Angara River, Lake Baikal, and small lakes and ponds in the vicinity of Irkutsk and Tashkent. The series of experiments established that algae and higher aquatic plants are resistant to cyanides. A table shows the kinetic parameters of the removal of cyanide by algae and higher aquatic plants collected in Baikal. Of the multitude of species investigated for detoxifying ability, the most resistant were detected in the experimental basins and the most suitable were charophytes

  9. Diurnal adjustment in ultraviolet sunscreen protection is widespread among higher plants.

    Science.gov (United States)

    Barnes, Paul W; Flint, Stephan D; Tobler, Mark A; Ryel, Ronald J

    2016-05-01

    The accumulation of ultraviolet (UV)-absorbing compounds (flavonoids and related phenylpropanoids) in the epidermis of higher plants reduces the penetration of solar UV radiation to underlying tissues and is a primary mechanism of acclimation to changing UV conditions resulting from ozone depletion and climate change. Previously we reported that several herbaceous plant species were capable of rapid, diurnal adjustments in epidermal UV transmittance (T UV), but how widespread this phenomenon is among plants has been unknown. In the present study, we tested the generality of this response by screening 37 species of various cultivated and wild plants growing in four locations spanning a gradient of ambient solar UV and climate (Hawaii, Utah, Idaho and Louisiana). Non-destructive measurements of adaxial T UV indicated that statistically significant midday decreases in T UV occurred in 49 % of the species tested, including both herbaceous and woody growth forms, and there was substantial interspecific variation in the magnitude of these changes. In general, plants in Louisiana exhibited larger diurnal changes in T UV than those in the other locations. Moreover, across all taxa, the magnitude of these changes was positively correlated with minimum daily air temperatures but not daily UV irradiances. Results indicate that diurnal changes in UV shielding are widespread among higher plants, vary both within and among species and tend to be greatest in herbaceous plants growing in warm environments. These findings suggest that plant species differ in their UV protection "strategies" though the functional and ecological significance of this variation in UV sunscreen protection remains unclear at present.

  10. Phototolerance of lichens, mosses and higher plants in an alpine environment: analysis of photoreactions.

    Science.gov (United States)

    Heber, U; Bilger, W; Bligny, R; Lange, O L

    2000-11-01

    Adaptation to excessive light is one of the requirements of survival in an alpine environment particularly for poikilohydric organisms which in contrast to the leaves of higher plants tolerate full dehydration. Changes in modulated chlorophyll fluorescence and 820-nm absorption were investigated in the lichens Xanthoria elegans (Link) Th. Fr. and Rhizocarpon geographicum (L.) DC, in the moss Grimmia alpestris Limpr. and the higher plants Geum montanum L., Gentiana lutea L. and Pisum sativum L., all collected at altitudes higher than 2000 m above sea level. In the dehydrated state, chlorophyll fluorescence was very low in the lichens and the moss, but high in the higher plants. It increased on rehydration in the lichens and the moss, but decreased in the higher plants. Light-induced charge separation in photosystem II was indicated by pulse-induced fluorescence increases only in dried leaves, not in the dry moss and dry lichens. Strong illumination caused photodamage in the dried leaves, but not in the dry moss and dry lichens. Light-dependent increases in 820-nm absorption revealed formation of potential quenchers of chlorophyll fluorescence in all dehydrated plants, but energy transfer to quenchers decreased chlorophyll fluorescence only in the moss and the lichens, not in the higher plants. In hydrated systems, coupled cyclic electron transport is suggested to occur concurrently with linear electron transport under strong actinic illumination particularly in the lichens because far more electrons became available after actinic illumination for the reduction of photo-oxidized P700 than were available in the pool of electron carriers between photosystems II and I. In the moss Grimmia, but not in the lichens or in leaves, light-dependent quenching of chlorophyll fluorescence was extensive even under nitrogen, indicating anaerobic thylakoid acidification by persistent cyclic electron transport. In the absence of actinic illumination, acidification by ca. 8% CO2 in

  11. 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.

  12. Overexpression of Nictaba-Like Lectin Genes from Glycine max Confers Tolerance towards Pseudomonas syringae Infection, Aphid Infestation and Salt Stress in Transgenic Arabidopsis Plants

    Directory of Open Access Journals (Sweden)

    Sofie Van Holle

    2016-10-01

    Full Text Available Plants have evolved a sophisticated immune system that allows them to recognize invading pathogens by specialized receptors. Carbohydrate-binding proteins or lectins are part of this immune system and especially the lectins that reside in the nucleocytoplasmic compartment are known to be implicated in biotic and abiotic stress responses. The class of Nictaba-like lectins (NLL groups all proteins with homology to the tobacco (Nicotiana tabacum lectin, known as a stress-inducible lectin. Here we focus on two Nictaba homologs from soybean (Glycine max, referred to as GmNLL1 and GmNLL2. Confocal laser scanning microscopy of fusion constructs with the green fluorescent protein either transiently expressed in Nicotiana benthamiana leaves or stably transformed in tobacco BY-2 suspension cells revealed a nucleocytoplasmic localization for the GmNLLs under study. RT-qPCR analysis of the transcript levels for the Nictaba-like lectins in soybean demonstrated that the genes are expressed in several tissues throughout the development of the plant. Furthermore, it was shown that salt treatment, Phytophthora sojae infection and Aphis glycines infestation trigger the expression of particular NLL genes. Stress experiments with Arabidopsis lines overexpressing the NLLs from soybean yielded an enhanced tolerance of the plant towards bacterial infection (Pseudomonas syringae, insect infestation (Myzus persicae and salinity. Our data showed a better performance of the transgenic lines compared to wild type plants, indicating that the NLLs from soybean are implicated in the stress response. These data can help to further elucidate the physiological importance of the Nictaba-like lectins from soybean, which can ultimately lead to the design of crop plants with a better tolerance to changing environmental conditions.

  13. Enhanced Botrytis cinerea resistance of Arabidopsis plants grown in compost may be explained by increased expression of defense-related genes, as revealed by microarray analysis.

    Directory of Open Access Journals (Sweden)

    Guillem Segarra

    Full Text Available Composts are the products obtained after the aerobic degradation of different types of organic matter waste and can be used as substrates or substrate/soil amendments for plant cultivation. There is a small but increasing number of reports that suggest that foliar diseases may be reduced when using compost, rather than standard substrates, as growing medium. The purpose of this study was to examine the gene expression alteration produced by the compost to gain knowledge of the mechanisms involved in compost-induced systemic resistance. A compost from olive marc and olive tree leaves was able to induce resistance against Botrytis cinerea in Arabidopsis, unlike the standard substrate, perlite. Microarray analyses revealed that 178 genes were differently expressed, with a fold change cut-off of 1, of which 155 were up-regulated and 23 were down-regulated in compost-grown, as against perlite-grown plants. A functional enrichment study of up-regulated genes revealed that 38 Gene Ontology terms were significantly enriched. Response to stress, biotic stimulus, other organism, bacterium, fungus, chemical and abiotic stimulus, SA and ABA stimulus, oxidative stress, water, temperature and cold were significantly enriched, as were immune and defense responses, systemic acquired resistance, secondary metabolic process and oxireductase activity. Interestingly, PR1 expression, which was equally enhanced by growing the plants in compost and by B. cinerea inoculation, was further boosted in compost-grown pathogen-inoculated plants. Compost triggered a plant response that shares similarities with both systemic acquired resistance and ABA-dependent/independent abiotic stress responses.

  14. The embryogenesis in Arabidopsis thaliana following the γ-irradiation of the plants in the generative phase

    International Nuclear Information System (INIS)

    Akhundova, G.G.; Grinich, L.I.; Shevchenko, V.V.

    1978-01-01

    The flowers and young pods of the Arabidopsis thaliana (B 3 -B 7 phases of development) were subjected to the γ-irradiation with the dose of 4kr. The irradiation did not influence upon duration of phases of flower development, independently of the phase it has been conducted. Cytological characteristics of embryos are given for each phase under study. The duration of embyogenesis (from zygote up to spherical stage) under control and after irradiation was practically identical. The irradiation excited various anomalies of development. The most frequently met type of violations is the first division of apical cell by transverse septum instead of longitudinal one. Observed were the irregular division of suspensor cells, arrest of embryo apical cell division at normal suspensor division, irregular septum location and irregular form of embryo body. Maximum of violations in seed-lobe formation was marked after irradiation of young pods (B 6 -B 7 phases)

  15. Plant species richness sustains higher trophic levels of soil nematode communities after consecutive environmental perturbations.

    Science.gov (United States)

    Cesarz, Simone; Ciobanu, Marcel; Wright, Alexandra J; Ebeling, Anne; Vogel, Anja; Weisser, Wolfgang W; Eisenhauer, Nico

    2017-07-01

    The magnitude and frequency of extreme weather events are predicted to increase in the future due to ongoing climate change. In particular, floods and droughts resulting from climate change are thought to alter the ecosystem functions and stability. However, knowledge of the effects of these weather events on soil fauna is scarce, although they are key towards functioning of terrestrial ecosystems. Plant species richness has been shown to affect the stability of ecosystem functions and food webs. Here, we used the occurrence of a natural flood in a biodiversity grassland experiment that was followed by a simulated summer drought experiment, to investigate the interactive effects of plant species richness, a natural flood, and a subsequent summer drought on nematode communities. Three and five months after the natural flooding, effects of flooding severity were still detectable in the belowground system. We found that flooding severity decreased soil nematode food-web structure (loss of K-strategists) and the abundance of plant feeding nematodes. However, high plant species richness maintained higher diversity and abundance of higher trophic levels compared to monocultures throughout the flood. The subsequent summer drought seemed to be of lower importance but reversed negative flooding effects in some cases. This probably occurred because the studied grassland system is well adapted to drought, or because drought conditions alleviated the negative impact of long-term soil waterlogging. Using soil nematodes as indicator taxa, this study suggests that high plant species richness can maintain soil food web complexity after consecutive environmental perturbations.

  16. Research on mutation generation in higher plants with heavy ions at NIRS-HIMAC

    International Nuclear Information System (INIS)

    Okamura, M.; Watanabe, S.; Watanabe, M.; Toguri, T.; Furusawa, Y.

    2006-01-01

    Plants are closely related to medical treatment in medicine, foods, herbs and medical care by gardening. Ion beams have much higher linear energy transfer (LET) and relative biological effectiveness than those of gamma rays and X-rays. Ion beams are supposed to be useful as new mutagen to obtain novel mutants with superior characteristics in higher plants. In this study, the influence of heavy ions irradiation on bud growth was examined in carnation and the mutation generation was inspected in babies' breath. The growth of carnation buds began to decrease at 10 Gy and the median growth dose was estimated at 35 Gy for 290 Mev/u carbon ion beams. Mutants with petaloid leaves were observed in babies' breath by the irradiation of 290 Mev/u carbon ion beams at 20Gy. We will examine the mutation rates and spectrum for 290 MeV/u carbon, 400 MeV/u neon and 500 MeV/u argon ion beams to find optimum use of the beams in plant breeding. The efficient system to generate useful mutants using heavy ions at NIRS-HIMAC will be developed in higher plants. (author)

  17. Higher plants and UV-B radiation: balancing damage, repair and acclimation

    International Nuclear Information System (INIS)

    Jansen, M.A.K.; Gaba, V.; Greenberg, B.M.

    1998-01-01

    Although UV-B is a minor component of sunlight, it has a disproportionately damaging effect on higher plants. Ultraviolet-sensitive targets include DNA, proteins and membranes, and these must be protected for normal growth and development. DNA repair and secondary metabolite accumulation during exposure to UV-B have been characterized in considerable detail, but little is known about the recovery of photosynthesis, induction of free-radical scavenging and morphogenic changes. A future challenge is to elucidate how UV-B-exposed plants balance damage, repair, acclimation and adaptation responses in a photobiologically dynamic environment. (author)

  18. Cadmium against higher plant photosynthesis - a variety of effects and where do they possibly come from?

    International Nuclear Information System (INIS)

    Krupa, Z.

    1999-01-01

    The complexity of in vivo toxic effects of Cd on higher plants makes almost impossible an accurate distinction between direct and indirect mechanisms of its action on the photosynthetic apparatus. We, therefore, postulate that multiple Cd effects on plant physiological and metabolic processes may finally be focused on photosynthesis. This would also explain the phenomenon that only a small fraction of Cd entering chloroplasts may cause such disastrous changes in their structure and function. In return, the inhibition of photosynthesis affects numerous metabolic pathways dependent on the primary carbon metabolism. (orig.)

  19. Abscisic acid and ethylene in mutants of Arabidopsis thaliana differing in their resistance to ultraviolet (UV-B) radiation stress

    International Nuclear Information System (INIS)

    Rakitina, T.Ya.; Vlasov, P.V.; Jalilova, F.Kh.; Kefeli, V.I.

    1994-01-01

    The effects of ultraviolet irradiation (between 280 and 320 nm) on plant survival, ethylene evolution, and abscisic acid (ABA) content were studied in Arabidopsis thaliana (L.) Heunh. plants. Three genetic lines of Arabidopsis differing in their resistance to ultraviolet (UV-B) radiation stress were used. UV-B irradiation had detrimental effects on plant survival, enhanced ethylene evolution, and increased ABA content in the plants of all three lines. The higher ultraviolet dose was absorbed, the less was the number of surviving plants and the higher were the levels of both phytohormones. The maximum ethylene evolution occurred during the initial two to four hours after irradiation, but the ABA content peaked only after 24 h. The most resistant line showed the highest ABA content and the fastest ethylene evolution, whereas, in the susceptible line, both indices were the lowest. After UV-B treatment, the ABA-deficient Arabidopsis mutant evolved four to six times more ethylene than the plants with normal ABA content. Stress ethylene production evidently did not depend on the level of endogenous ABA as the kinetics of ethylene evolution was similar in the ABA-deficient mutant and in other studied Arabidopsis lines

  20. Induction of Systemic Resistance against Aphids by Endophytic Bacillus velezensis YC7010 via Expressing PHYTOALEXIN DEFICIENT4 in Arabidopsis.

    Science.gov (United States)

    Rashid, Md Harun-Or-; Khan, Ajmal; Hossain, Mohammad T; Chung, Young R

    2017-01-01

    Aphids are the most destructive insect pests. They suck the sap and transmit plant viruses, causing widespread yield loss of many crops. A multifunctional endophytic bacterial strain Bacillus velezensis YC7010 has been found to induce systemic resistance against bacterial and fungal pathogens of rice. However, its activity against insects attack and underlying cellular and molecular defense mechanisms are not elucidated yet. Here, we show that root drenching of Arabidopsis seedlings with B. velezensis YC7010 can induce systemic resistance against green peach aphid (GPA), Myzus persicae . Treatment of bacterial suspension of B. velezensis YC7010 at 2 × 10 7 CFU/ml to Arabidopsis rhizosphere induced higher accumulation of hydrogen peroxide, cell death, and callose deposition in leaves compared to untreated plants at 6 days after infestation of GPA. Salicylic acid, jasmonic acid, ethylene, and abscisic acid were not required to confer defense against GPA in Arabidopsis plants treated by B. velezensis YC7010. Bacterial treatment with B. velezensis YC7010 significantly reduced settling, feeding and reproduction of GPA on Arabidopsis leaves via strongly expressing senescence-promoting gene PHYTOALEXIN DEFICIENT4 ( PAD4 ) while suppressing BOTRYTIS-INDUCED KINASE1 ( BIK1 ). These results indicate that B. velezensis YC7010-induced systemic resistance to the GPA is a hypersensitive response mainly dependent on higher expression of PAD4 with suppression of BIK1 , resulting in more accumulation of hydrogen peroxide, cell death, and callose deposition in Arabidopsis .

  1. Induction of Systemic Resistance against Aphids by Endophytic Bacillus velezensis YC7010 via Expressing PHYTOALEXIN DEFICIENT4 in Arabidopsis

    Science.gov (United States)

    Rashid, Md. Harun-Or-; Khan, Ajmal; Hossain, Mohammad T.; Chung, Young R.

    2017-01-01

    Aphids are the most destructive insect pests. They suck the sap and transmit plant viruses, causing widespread yield loss of many crops. A multifunctional endophytic bacterial strain Bacillus velezensis YC7010 has been found to induce systemic resistance against bacterial and fungal pathogens of rice. However, its activity against insects attack and underlying cellular and molecular defense mechanisms are not elucidated yet. Here, we show that root drenching of Arabidopsis seedlings with B. velezensis YC7010 can induce systemic resistance against green peach aphid (GPA), Myzus persicae. Treatment of bacterial suspension of B. velezensis YC7010 at 2 × 107 CFU/ml to Arabidopsis rhizosphere induced higher accumulation of hydrogen peroxide, cell death, and callose deposition in leaves compared to untreated plants at 6 days after infestation of GPA. Salicylic acid, jasmonic acid, ethylene, and abscisic acid were not required to confer defense against GPA in Arabidopsis plants treated by B. velezensis YC7010. Bacterial treatment with B. velezensis YC7010 significantly reduced settling, feeding and reproduction of GPA on Arabidopsis leaves via strongly expressing senescence-promoting gene PHYTOALEXIN DEFICIENT4 (PAD4) while suppressing BOTRYTIS-INDUCED KINASE1 (BIK1). These results indicate that B. velezensis YC7010-induced systemic resistance to the GPA is a hypersensitive response mainly dependent on higher expression of PAD4 with suppression of BIK1, resulting in more accumulation of hydrogen peroxide, cell death, and callose deposition in Arabidopsis. PMID:28261260

  2. Circadian Stress Regimes Affect the Circadian Clock and Cause Jasmonic Acid-Dependent Cell Death in Cytokinin-Deficient Arabidopsis Plants[OPEN

    Science.gov (United States)

    Nitschke, Silvia; Cortleven, Anne; Iven, Tim; Havaux, Michel; Schmülling, Thomas

    2016-01-01

    The circadian clock helps plants measure daylength and adapt to changes in the day-night rhythm. We found that changes in the light-dark regime triggered stress responses, eventually leading to cell death, in leaves of Arabidopsis thaliana plants with reduced cytokinin levels or defective cytokinin signaling. Prolonged light treatment followed by a dark period induced stress and cell death marker genes while reducing photosynthetic efficiency. This response, called circadian stress, is also characterized by altered expression of clock and clock output genes. In particular, this treatment strongly reduced the expression of CIRCADIAN CLOCK ASSOCIATED1 (CCA1) and LATE ELONGATED HYPOCOTYL (LHY). Intriguingly, similar changes in gene expression and cell death were observed in clock mutants lacking proper CCA1 and LHY function. Circadian stress caused strong changes in reactive oxygen species- and jasmonic acid (JA)-related gene expression. The activation of the JA pathway, involving the accumulation of JA metabolites, was crucial for the induction of cell death, since the cell death phenotype was strongly reduced in the jasmonate resistant1 mutant background. We propose that adaptation to circadian stress regimes requires a normal cytokinin status which, acting primarily through the AHK3 receptor, supports circadian clock function to guard against the detrimental effects of circadian stress. PMID:27354555

  3. Early Effects of Altered Gravity Environments on Plant Cell Growth and Cell Proliferation: Characterization of Morphofunctional Nucleolar Types in an Arabidopsis Cell Culture System

    Energy Technology Data Exchange (ETDEWEB)

    Manzano, Ana I.; Herranz, Raúl; Manzano, Aránzazu [Centro de Investigaciones Biológicas (CSIC), Madrid (Spain); Loon, Jack J. W. A. van [Department of Oral and Maxillofacial Surgery/Oral Pathology, Dutch Experiment Support Center, VU University Medical Center, Amsterdam (Netherlands); Academic Centre for Dentistry Amsterdam (ACTA), Amsterdam (Netherlands); ESA-ESTEC, TEC-MMG, Noordwijk (Netherlands); Medina, F. Javier, E-mail: fjmedina@cib.csic.es [Centro de Investigaciones Biológicas (CSIC), Madrid (Spain)

    2016-02-05

    Changes in the cell growth rate of an in vitro cellular system in Arabidopsis thaliana induced by short exposure to an altered gravity environment have been estimated by a novel approach. The method consisted of defining three structural nucleolar types which are easy and reliable indicators of the ribosome biogenesis activity and, consequently, of protein biosynthesis, a parameter strictly correlated to cell growth in this cellular system. The relative abundance of each nucleolar type was statistically assessed in different conditions of gravity. Samples exposed to simulated microgravity for 200 min showed a significant decrease in nucleolar activity compared to 1g controls, whereas samples exposed to hypergravity (2g) for the same period showed nucleolar activity slightly increased. These effects could be considered as an early cellular response to the environmental alteration, given the short duration of the treatment. The functional significance of the structural data was validated by a combination of several different well-known parameters, using microscopical, flow cytometry, qPCR, and proteomic approaches, which showed that the decreased cell growth rate was decoupled from an increased cell proliferation rate under simulated microgravity, and the opposite trend was observed under hypergravity. Actually, not all parameters tested showed the same quantitative changes, indicating that the response to the environmental alteration is time-dependent. These results are in agreement with previous observations in root meristematic cells and they show the ability of plant cells to produce a response to gravity changes, independently of their integration into plant organs.

  4. 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; Nishino, Tsuneyo; Iwano, Megumi; Takayama, Seiji; Koizumi, Nozomu

    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.

  5. The complete mitochondrial genome of Gossypium hirsutum and evolutionary analysis of higher plant mitochondrial genomes.

    Science.gov (United States)

    Liu, Guozheng; Cao, Dandan; Li, Shuangshuang; Su, Aiguo; Geng, Jianing; Grover, Corrinne E; Hu, Songnian; Hua, Jinping

    2013-01-01

    Mitochondria are the main manufacturers of cellular ATP in eukaryotes. The plant mitochondrial genome contains large number of foreign DNA and repeated sequences undergone frequently intramolecular recombination. Upland Cotton (Gossypium hirsutum L.) is one of the main natural fiber crops and also an important oil-producing plant in the world. Sequencing of the cotton mitochondrial (mt) genome could be helpful for the evolution research of plant mt genomes. We utilized 454 technology for sequencing and combined with Fosmid library of the Gossypium hirsutum mt genome screening and positive clones sequencing and conducted a series of evolutionary analysis on Cycas taitungensis and 24 angiosperms mt genomes. After data assembling and contigs joining, the complete mitochondrial genome sequence of G. hirsutum was obtained. The completed G.hirsutum mt genome is 621,884 bp in length, and contained 68 genes, including 35 protein genes, four rRNA genes and 29 tRNA genes. Five gene clusters are found conserved in all plant mt genomes; one and four clusters are specifically conserved in monocots and dicots, respectively. Homologous sequences are distributed along the plant mt genomes and species closely related share the most homologous sequences. For species that have both mt and chloroplast genome sequences available, we checked the location of cp-like migration and found several fragments closely linked with mitochondrial genes. The G. hirsutum mt genome possesses most of the common characters of higher plant mt genomes. The existence of syntenic gene clusters, as well as the conservation of some intergenic sequences and genic content among the plant mt genomes suggest that evolution of mt genomes is consistent with plant taxonomy but independent among different species.

  6. Interaction between sugar and abscisic acid signalling during early seedling development in Arabidopsis

    NARCIS (Netherlands)

    Dekkers, B.J.W.; Schuurmans, J.A.M.J.; Smeekens, J.C.M.

    2008-01-01

    Sugars regulate important processes and affect the expression of many genes in plants. Characterization of Arabidopsis (Arabidopsis thaliana) mutants with altered sugar sensitivity revealed the function of abscisic acid (ABA) signalling in sugar responses. However, the exact interaction between

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

    Science.gov (United States)

    Albrecht, Verónica; Ingenfeld, Anke; Apel, Klaus

    2006-03-01

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

  8. Soil mixture composition alters Arabidopsis susceptibility to Pseudomonas syringae infection

    Science.gov (United States)

    Pseudomonas syringae is a Gram-negative bacterial pathogen that causes disease on more than 100 different plant species, including the model plant Arabidopsis thaliana. Dissection of the Arabidopsis thaliana-Pseudomonas syringae pathosystem has identified many factors that contribute to successful ...

  9. Arabidopsis thaliana polyamine content is modified by the interaction with different Trichoderma species.

    Science.gov (United States)

    Salazar-Badillo, Fatima Berenice; Sánchez-Rangel, Diana; Becerra-Flora, Alicia; López-Gómez, Miguel; Nieto-Jacobo, Fernanda; Mendoza-Mendoza, Artemio; Jiménez-Bremont, Juan Francisco

    2015-10-01

    Plants are associated with a wide range of microorganisms throughout their life cycle, and some interactions result on plant benefits. Trichoderma species are plant beneficial fungi that enhance plant growth and development, contribute to plant nutrition and induce defense responses. Nevertheless, the molecules involved in these beneficial effects still need to be identify. Polyamines are ubiquitous molecules implicated in plant growth and development, and in the establishment of plant microbe interactions. In this study, we assessed the polyamine profile in Arabidopsis plants during the interaction with Trichoderma virens and Trichoderma atroviride, using a system that allows direct plant-fungal contact or avoids their physical interaction (split system). The plantlets that grew in the split system exhibited higher biomass than the ones in direct contact with Trichoderma species. After 3 days of interaction, a significant decrease in Arabidopsis polyamine levels was observed in both systems (direct contact and split). After 5 days of interaction polyamine levels were increased. The highest levels were observed with T. atroviride (split system), and with T. virens (direct contact). The expression levels of Arabidopsis ADC1 and ADC2 genes during the interaction with the fungi were also assessed. We observed a time dependent regulation of ADC1 and ADC2 genes, which correlates with polyamine levels. Our data show an evident change in polyamine profile during Arabidopsis - Trichoderma interaction, accompanied by evident alterations in plant root architecture. Polyamines could be involved in the changes undergone by plant during the interaction with this beneficial fungus. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  10. An Arabidopsis callose synthase

    DEFF Research Database (Denmark)

    Ostergaard, Lars; Petersen, Morten; Mattsson, Ole

    2002-01-01

    in the Arabidopsis mpk4 mutant which exhibits systemic acquired resistance (SAR), elevated beta-1,3-glucan synthase activity, and increased callose levels. In addition, AtGsl5 is a likely target of salicylic acid (SA)-dependent SAR, since AtGsl5 mRNA accumulation is induced by SA in wild-type plants, while...... expression of the nahG salicylate hydroxylase reduces AtGsl5 mRNA levels in the mpk4 mutant. These results indicate that AtGsl5 is likely involved in callose synthesis in flowering tissues and in the mpk4 mutant....

  11. A Novel Sugar Transporter from Dianthus spiculifolius, DsSWEET12, Affects Sugar Metabolism and Confers Osmotic and Oxidative Stress Tolerance in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Aimin Zhou

    2018-02-01

    Full Text Available Plant SWEETs (sugars will eventually be exported transporters play a role in plant growth and plant response to biotic and abiotic stresses. In the present study, DsSWEET12 from Dianthus spiculifolius was identified and characterized. Real-time quantitative PCR analysis revealed that DsSWEET12 expression was induced by sucrose starvation, mannitol, and hydrogen peroxide. Colocalization experiment showed that the DsSWEET12-GFP fusion protein was localized to the plasma membrane, which was labeled with FM4-64 dye, in Arabidopsis and suspension cells of D. spiculifolius. Compared to wild type plants, transgenic Arabidopsis seedlings overexpressing DsSWEET12 have longer roots and have a greater fresh weight, which depends on sucrose content. Furthermore, a relative root length analysis showed that transgenic Arabidopsis showed higher tolerance to osmotic and oxidative stresses. Finally, a sugar content analysis showed that the sucrose content in transgenic Arabidopsis was less than that in the wild type, while fructose and glucose contents were higher than those in the wild type. Taken together, our results suggest that DsSWEET12 plays an important role in seedling growth and plant response to osmotic and oxidative stress in Arabidopsis by influencing sugar metabolism.

  12. A Novel Sugar Transporter from Dianthus spiculifolius, DsSWEET12, Affects Sugar Metabolism and Confers Osmotic and Oxidative Stress Tolerance in Arabidopsis.

    Science.gov (United States)

    Zhou, Aimin; Ma, Hongping; Feng, Shuang; Gong, Shufang; Wang, Jingang

    2018-02-07

    Plant SWEETs (sugars will eventually be exported transporters) play a role in plant growth and plant response to biotic and abiotic stresses. In the present study, DsSWEET12 from Dianthus spiculifolius was identified and characterized. Real-time quantitative PCR analysis revealed that DsSWEET12 expression was induced by sucrose starvation, mannitol, and hydrogen peroxide. Colocalization experiment showed that the DsSWEET12-GFP fusion protein was localized to the plasma membrane, which was labeled with FM4-64 dye, in Arabidopsis and suspension cells of D. spiculifolius . Compared to wild type plants, transgenic Arabidopsis seedlings overexpressing DsSWEET12 have longer roots and have a greater fresh weight, which depends on sucrose content. Furthermore, a relative root length analysis showed that transgenic Arabidopsis showed higher tolerance to osmotic and oxidative stresses. Finally, a sugar content analysis showed that the sucrose content in transgenic Arabidopsis was less than that in the wild type, while fructose and glucose contents were higher than those in the wild type. Taken together, our results suggest that DsSWEET12 plays an important role in seedling growth and plant response to osmotic and oxidative stress in Arabidopsis by influencing sugar metabolism.

  13. Importance of molybdenum in the nitrogen metabolism of microorganisms and higher plants

    Energy Technology Data Exchange (ETDEWEB)

    Mulder, E G

    1948-01-01

    The effect of molybdenum on the growth of microorganisms and higher plants and on some well-defined biochemical reactions was investigated. Results indicate that Aspergillus niger requires small amounts of molybdenum when growing in a culture solution supplied with nitrate nitrogen. With ammonium sulfate as a source of nitrogen, the response of the fungus to molybdenum was much smaller. It was shown that this different response of Aspergillus to molybdenum was not brought about by a difference in purity of both nitrogen compounds used, nor by a difference in absorption of the molybdenum impurity, but by a considerably higher requirement of molybdenum in a medium with nitrate nitrogen. The growth-rate curve and the increasing sporulation of Aspergillus niger with increasing amounts of molybdenum were used in estimating very small amounts of this element in various materials. In culture solution experiments with tomato, barley and oat plants the effect of traces of molybdenum on the growth of these plants was investigated. In good agreement with the results of the experiments with Aspergillus and denitrifying bacteria it could be shown that in the green plant as in these microorganisms molybdenum is acting as a catalyst in nitrate reduction. In experiments with Azotobacter chroococcum and leguminous plants the effect of molybdenum on the fixation of gaseous N/sub 2/ was studied. In culture solutions with pea plants the effect of molybdenum on the nitrogen fixation of the nodules was investigated. In the absence of molybdenum as well as in a complete nutrient medium many nodules were formed. 30 references, 6 figures, 16 tables.

  14. Higher plant modelling for life support applications: first results of a simple mechanistic model

    Science.gov (United States)

    Hezard, Pauline; Dussap, Claude-Gilles; Sasidharan L, Swathy

    2012-07-01

    In the case of closed ecological life support systems, the air and water regeneration and food production are performed using microorganisms and higher plants. Wheat, rice, soybean, lettuce, tomato or other types of eatable annual plants produce fresh food while recycling CO2 into breathable oxygen. Additionally, they evaporate a large quantity of water, which can be condensed and used as potable water. This shows that recycling functions of air revitalization and food production are completely linked. Consequently, the control of a growth chamber for higher plant production has to be performed with efficient mechanistic models, in order to ensure a realistic prediction of plant behaviour, water and gas recycling whatever the environmental conditions. Purely mechanistic models of plant production in controlled environments are not available yet. This is the reason why new models must be developed and validated. This work concerns the design and test of a simplified version of a mathematical model coupling plant architecture and mass balance purposes in order to compare its results with available data of lettuce grown in closed and controlled chambers. The carbon exchange rate, water absorption and evaporation rate, biomass fresh weight as well as leaf surface are modelled and compared with available data. The model consists of four modules. The first one evaluates plant architecture, like total leaf surface, leaf area index and stem length data. The second one calculates the rate of matter and energy exchange depending on architectural and environmental data: light absorption in the canopy, CO2 uptake or release, water uptake and evapotranspiration. The third module evaluates which of the previous rates is limiting overall biomass growth; and the last one calculates biomass growth rate depending on matter exchange rates, using a global stoichiometric equation. All these rates are a set of differential equations, which are integrated with time in order to provide

  15. Preliminary Modelling of Mass Flux at the Surface of Plant Leaves within the MELiSSA Higher Plant Compartments

    Science.gov (United States)

    Holmberg, Madeleine; Paille, Christel; Lasseur, Christophe

    The ESA project Micro Ecological Life Support System Alternative (MELiSSA) is an ecosystem of micro-organisms and higher plants, constructed with the objective of being operated as a tool to understand artificial ecosystems to be used for a long-term or permanent manned planetary base (e.g. Moon or Mars). The purpose of such a system is to provide for generation of food, water recycling, atmospheric regeneration and waste management within defined standards of quality and reliability. As MELiSSA consists of individual compartments which are connected to each other, the robustness of the system is fully dependent on the control of each compartment, as well as the flow management between them. Quality of consumables and reliability of the ecosystem rely on the knowledge, understanding and control of each of the components. This includes the full understanding of all processes related to the higher plants. To progress in that direction, this paper focuses on the mechanical processes driving the gas and liquid exchanges between the plant leaf and its environment. The process responsible for the mass transfer on the surface of plant leaves is diffusion. The diffusion flux is dependent on the behaviour of the stoma of the leaf and also on the leaf boundary layer (BL). In this paper, the physiology of the leaf is briefly examined in order to relate parameters such as light quality, light quantity, CO2 concentration, temperature, leaf water potential, humidity, vapour pressure deficit (VPD) gradients and pollutants to the opening or closing of stomata. The diffusion process is described theoretically and the description is compared to empirical approaches. The variables of the BL are examined and the effect airflow in the compartment has on the BL is investigated. Also presented is the impact changes in different environmental parameters may have on the fluid exchanges. Finally, some tests, to evaluate the accuracy of the concluded model, are suggested.

  16. Chloroplast Signaling Gates Thermotolerance in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Patrick J. Dickinson

    2018-02-01

    Full Text Available Temperature is a key environmental variable influencing plant growth and survival. Protection against high temperature stress in eukaryotes is coordinated by heat shock factors (HSFs, transcription factors that activate the expression of protective chaperones such as HEAT SHOCK PROTEIN 70 (HSP70; however, the pathway by which temperature is sensed and integrated with other environmental signals into adaptive responses is not well understood. Plants are exposed to considerable diurnal variation in temperature, and we have found that there is diurnal variation in thermotolerance in Arabidopsis thaliana, with maximal thermotolerance coinciding with higher HSP70 expression during the day. In a forward genetic screen, we identified a key role for the chloroplast in controlling this response, suggesting that light-induced chloroplast signaling plays a key role. Consistent with this, we are able to globally activate binding of HSFA1a to its targets by altering redox status in planta independently of a heat shock.

  17. Co-overexpressing a plasma membrane and a vacuolar membrane sodium/proton antiporter significantly improves salt tolerance in transgenic Arabidopsis plants.

    Science.gov (United States)

    The Arabidopsis gene AtNHX1 encodes a vacuolar membrane bound sodium/proton (Sodium/Hydrogen) antiporter that transports sodium into the vacuole and exports hydrogen into the cytoplasm. The Arabidopsis gene SOS1 encodes a plasma membrane bound sodium/hydrogen antiporter that exports sodium to the ex...

  18. Evolutionary history and stress regulation of the lectin superfamily in higher plants

    Directory of Open Access Journals (Sweden)

    Ramachandran Srinivasan

    2010-03-01

    Full Text Available Abstract Background Lectins are a class of carbohydrate-binding proteins. They play roles in various biological processes. However, little is known about their evolutionary history and their functions in plant stress regulation. The availability of full genome sequences from various plant species makes it possible to perform a whole-genome exploration for further understanding their biological functions. Results Higher plant genomes encode large numbers of lectin proteins. Based on their domain structures and phylogenetic analyses, a new classification system has been proposed. In this system, 12 different families have been classified and four of them consist of recently identified plant lectin members. Further analyses show that some of lectin families exhibit species-specific expansion and rapid birth-and-death evolution. Tandem and segmental duplications have been regarded as the major mechanisms to drive lectin expansion although retrogenes also significantly contributed to the birth of new lectin genes in soybean and rice. Evidence shows that lectin genes have been involved in biotic/abiotic stress regulations and tandem/segmental duplications may be regarded as drivers for plants to adapt various environmental stresses through duplication followed by expression divergence. Each member of this gene superfamily may play specialized roles in a specific stress condition and function as a regulator of various environmental factors such as cold, drought and high salinity as well as biotic stresses. Conclusions Our studies provide a new outline of the plant lectin gene superfamily and advance the understanding of plant lectin genes in lineage-specific expansion and their functions in biotic/abiotic stress-related developmental processes.

  19. The Arabidopsis-related halophyte Thellungiella halophila: boron tolerance via boron complexation with metabolites?

    Science.gov (United States)

    Lamdan, Netta Li; Attia, Ziv; Moran, Nava; Moshelion, Menachem

    2012-04-01

    Tolerance to boron (B) is still not completely understood. We tested here the hypothesis that Thellungiella halophila, an Arabidopsis thaliana-related 'extremophile' plant, with abundance of B in its natural environment, is tolerant to B, and examined the potential mechanisms of this tolerance. With 1-10 mm B applied ([B](ext)) to Thellungiella and Arabidopsis grown in hydroponics, the steady-state accumulated B concentration ([B](int)) in the root was below [B](ext), and was similar in both, suggesting both extrude B actively. Whether grown in soil or hydroponically, the shoot [B](int) was higher in Arabidopsis than in Thellungiella, suggesting more effective net B exclusion by Thellungiella root. Arabidopsis exhibited toxicity symptoms including reduced shoot fresh weight (FW), but Thellungiella was not affected, even at similar levels of shoot-accumulated [B](int) (about 10 to 40 mm B in 'shoot water'), suggesting additional B tolerance mechanism in Thellungiella shoot. At [B](ext) = 5 mm, the summed shoot concentration of the potentially B-binding polyhydroxyl metabolites (malic acid, fructose, glucose, sucrose and citric acid) in Arabidopsis was below [B](int) , but in Thellungiella it was over twofold higher than [B](int) , and therefore likely to allow appreciable 1:2 boron-metabolite complexation in the shoot. This, we suggest, is an important component of Thellungiella B tolerance mechanism. © 2011 Blackwell Publishing Ltd.

  20. Overexpression of PtABCC1 contributes to mercury tolerance and accumulation in Arabidopsis and poplar.

    Science.gov (United States)

    Sun, Liping; Ma, Yifeng; Wang, Huihong; Huang, Weipeng; Wang, Xiaozhu; Han, Li; Sun, Wanmei; Han, Erqin; Wang, Bangjun

    2018-03-18

    Mercury (Hg) is a highly biotoxic heavy metal that contaminates the environment. Phytoremediation is a green technology for environmental remediation and is used to clean up Hg contaminated soil in recent years. In this study, we isolated an ATP-binding cassette (ABC) transporter gene PtABCC1 from Populus trichocarpa and overexpressed it in Arabidopsis and poplar. The transgenic plants conferred higher Hg tolerance than wild type (WT) plants, and overexpression of PtABCC1 could lead to 26-72% or 7-160% increase of Hg accumulation in Arabidopsis or poplar plants, respectively. These results demonstrated that PtABCC1 plays a crucial role in enhancing tolerance and accumulation to Hg in plants, which provides a promising way for phytoremediation of Hg contamination. Copyright © 2018 Elsevier Inc. All rights reserved.

  1. How common is ecological speciation in plant-feeding insects? A 'Higher' Nematinae perspective

    Directory of Open Access Journals (Sweden)

    Nyman Tommi

    2010-09-01

    Full Text Available Abstract Background Ecological speciation is a process in which a transiently resource-polymorphic species divides into two specialized sister lineages as a result of divergent selection pressures caused by the use of multiple niches or environments. Ecology-based speciation has been studied intensively in plant-feeding insects, in which both sympatric and allopatric shifts onto novel host plants could speed up diversification. However, while numerous examples of species pairs likely to have originated by resource shifts have been found, the overall importance of ecological speciation in relation to other, non-ecological speciation modes remains unknown. Here, we apply phylogenetic information on sawflies belonging to the 'Higher' Nematinae (Hymenoptera: Tenthredinidae to infer the frequency of niche shifts in relation to speciation events. Results Phylogenetic trees reconstructed on the basis of DNA sequence data show that the diversification of higher nematines has involved frequent shifts in larval feeding habits and in the use of plant taxa. However, the inferred number of resource shifts is considerably lower than the number of past speciation events, indicating that the majority of divergences have occurred by non-ecological allopatric speciation; based on a time-corrected analysis of sister species, we estimate that a maximum of c. 20% of lineage splits have been triggered by a change in resource use. In addition, we find that postspeciational changes in geographic distributions have led to broad sympatry in many species having identical host-plant ranges. Conclusion Our analysis indicates that the importance of niche shifts for the diversification of herbivorous insects is at present implicitly and explicitly overestimated. In the case of the Higher Nematinae, employing a time correction for sister-species comparisons lowered the proportion of apparent ecology-based speciation events from c. 50-60% to around 20%, but such corrections are

  2. Site-directed mutagenesis of the Arabidopsis heterotrimeric G protein β subunit suggests divergent mechanisms of effector activation between plant and animal G proteins.

    Science.gov (United States)

    Chakravorty, David; Trusov, Yuri; Botella, José Ramón

    2012-03-01

    Heterotrimeric G proteins are integral components of signal transduction in humans and other mammals and have been therefore extensively studied. However, while they are known to mediate many processes, much less is currently known about the effector pathways and molecular mechanisms used by these proteins to regulate effectors in plants. We designed a complementation strategy to study G protein signaling in Arabidopsis thaliana, particularly the mechanism of action of AGB1, the sole identified β subunit. We used biochemical and effector regulation data from human G protein studies to identify four potentially important residues for site-directed mutagenesis (T65, M111, D250 and W361 of AGB1). Each residue was individually mutated and the resulting mutated protein introduced in the agb1-2 mutant background under the control of the native AGB1 promoter. Interestingly, even though these mutations have been shown to have profound effects on effector signaling in humans, all the mutated subunits were able to restore thirteen of the fifteen Gβ-deficient phenotypes characterized in this study. Only one mutated protein, T65A was unable to complement the hypersensitivity to mannitol during germination observed in agb1 mutants; while only D250A failed to restore lateral root numbers in the agb1 mutant to wild-type levels. Our results suggest that the mechanisms used in mammalian G protein signaling are not well conserved in plant G protein signaling, and that either the effectors used by plant G proteins, or the mechanisms used to activate them, are at least partially divergent from the well-studied mammalian G proteins.

  3. Ectopic expression of TaOEP16-2-5B, a wheat plastid outer envelope protein gene, enhances heat and drought stress tolerance in transgenic Arabidopsis plants.

    Science.gov (United States)

    Zang, Xinshan; Geng, Xiaoli; Liu, Kelu; Wang, Fei; Liu, Zhenshan; Zhang, Liyuan; Zhao, Yue; Tian, Xuejun; Hu, Zhaorong; Yao, Yingyin; Ni, Zhongfu; Xin, Mingming; Sun, Qixin; Peng, Huiru

    2017-05-01

    Abiotic stresses, such as heat and drought, are major environmental factors restricting crop productivity and quality worldwide. A plastid outer envelope protein gene, TaOEP16-2, was identified from our previous transcriptome analysis [1,2]. In this study, the isolation and functional characterization of the TaOEP16-2 gene was reported. Three homoeologous sequences of TaOEP16-2 were isolated from hexaploid wheat, which were localized on the chromosomes 5A, 5B and 5D, respectively. These three homoeologues exhibited different expression patterns under heat stress conditions, TaOEP16-2-5B was the dominant one, and TaOEP16-2-5B was selected for further analysis. Compared with wild type (WT) plants, transgenic Arabidopsis plants overexpressing the TaOEP16-2-5B gene exhibited enhanced tolerance to heat stress, which was supported by improved survival rate, strengthened cell membrane stability and increased sucrose content. It was also found that TaOEP16-2 was induced by drought stress and involved in drought stress tolerance. TaOEP16-2-5B has the same function in ABA-controlled seed germination as AtOEP16-2. Our results suggest that TaOEP16-2-5B plays an important role in heat and drought stress tolerance, and could be utilized in transgenic breeding of wheat and other crop plants. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Reverse genetic characterization of two paralogous acetoacetyl CoA thiolase genes in Arabidopsis reveals their importance in plant growth and development

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Huanan; Song, Zhihong; Nikolau, Basil J.

    2012-03-31

    Acetoacetyl CoA thiolase (AACT, EC 2.3.1.9) catalyzes the condensation of two acetyl CoA molecules to form acetoacetyl CoA. Two AACT‐encoding genes, At5g47720 (AACT1) and At5g48230 (AACT2), were functionally identified in the Arabidopsis genome by direct enzymological assays and functional expression in yeast. Promoter::GUS fusion experiments indicated that AACT1 is primarily expressed in the vascular system and AACT2 is highly expressed in root tips, young leaves, top stems and anthers. Characterization of T‐DNA insertion mutant alleles at each AACT locus established that AACT2 function is required for embryogenesis and for normal male gamete transmission. In contrast, plants lacking AACT1 function are completely viable and show no apparent growth phenotypes, indicating that AACT1 is functionally redundant with respect to AACT2 function. RNAi lines that express reduced levels of AACT2 show pleiotropic phenotypes, including reduced apical dominance, elongated life span and flowering duration, sterility, dwarfing, reduced seed yield and shorter root length. Microscopic analysis reveals that the reduced stature is caused by a reduction in cell size and fewer cells, and male sterility is caused by loss of the pollen coat and premature degeneration of the tapetal cells. Biochemical analyses established that the roots of AACT2 RNAi plants show quantitative and qualitative alterations in phytosterol profiles. These phenotypes and biochemical alterations are reversed when AACT2 RNAi plants are grown in the presence of mevalonate, which is consistent with the role of AACT2 in generating the bulk of the acetoacetyl CoA precursor required for the cytosol‐localized, mevalonate‐derived isoprenoid biosynthetic pathway.

  5. Overexpression of Arabidopsis NADPH-dependent thioredoxin reductase C (AtNTRC) confers freezing and cold shock tolerance to plants

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Jeong Chan [National Institute of Ecology, 1210 Geumgang-ro, Maseo-myeon, Seocheon-gun 325-813 (Korea, Republic of); Lee, Sangmin [Department of Biochemistry, College of Natural Sciences, Kangwon National University, Chuncheon (Korea, Republic of); Shin, Su Young [National Institute of Ecology, 1210 Geumgang-ro, Maseo-myeon, Seocheon-gun 325-813 (Korea, Republic of); Chae, Ho Byoung; Jung, Young Jun [Division of Applied Life Science - BK21+ program, PMBBRC, Gyeongsang National University, Jinju (Korea, Republic of); Jung, Hyun Suk [Department of Biochemistry, College of Natural Sciences, Kangwon National University, Chuncheon (Korea, Republic of); Lee, Kyun Oh [Division of Applied Life Science - BK21+ program, PMBBRC, Gyeongsang National University, Jinju (Korea, Republic of); Lee, Jung Ro, E-mail: leejr73@nie.re.kr [National Institute of Ecology, 1210 Geumgang-ro, Maseo-myeon, Seocheon-gun 325-813 (Korea, Republic of); Department of Biochemistry and Biophysics, Texas A& M University, College Station, TX (United States); Lee, Sang Yeol, E-mail: sylee@gnu.ac.kr [Division of Applied Life Science - BK21+ program, PMBBRC, Gyeongsang National University, Jinju (Korea, Republic of)

    2015-08-07

    Overexpression of AtNTRC (AtNTRC{sup OE}) in Arabidopsis thaliana led to a freezing and cold stress tolerance, whereas a knockout mutant (atntrc) showed a stress-sensitive phenotype. Biochemical analyses showed that the recombinant AtNTRC proteins exhibited a cryoprotective activity for malate dehydrogenase and lactic dehydrogenase. Furthermore, conclusive evidence of its interaction with nucleic acids in vitro is provided here on the basis of gel shift and electron microscopy analysis. Recombinant AtNTRC efficiently protected RNA and DNA from RNase A and metal catalyzed oxidation damage, respectively. The C-terminal thioredoxin domain is required for the nucleic acid–protein complex formation. From these results, it can be hypothesized that AtNTRC, which is known to be an electron donor of peroxiredoxin, contributes the stability of macromolecules under cold stress. - Highlights: • AtNTRC has a cryoprotective activity in vitro. • Overexpression of AtNTRC increases tolerance to freezing and cold shock stresses. • Thioredoxin domain of AtNTRC protects nucleic acids in vitro. • AtNTRC inhibits protein aggregation under freezing stress in vitro.

  6. Overexpression of Arabidopsis NADPH-dependent thioredoxin reductase C (AtNTRC) confers freezing and cold shock tolerance to plants

    International Nuclear Information System (INIS)

    Moon, Jeong Chan; Lee, Sangmin; Shin, Su Young; Chae, Ho Byoung; Jung, Young Jun; Jung, Hyun Suk; Lee, Kyun Oh; Lee, Jung Ro; Lee, Sang Yeol

    2015-01-01

    Overexpression of AtNTRC (AtNTRC OE ) in Arabidopsis thaliana led to a freezing and cold stress tolerance, whereas a knockout mutant (atntrc) showed a stress-sensitive phenotype. Biochemical analyses showed that the recombinant AtNTRC proteins exhibited a cryoprotective activity for malate dehydrogenase and lactic dehydrogenase. Furthermore, conclusive evidence of its interaction with nucleic acids in vitro is provided here on the basis of gel shift and electron microscopy analysis. Recombinant AtNTRC efficiently protected RNA and DNA from RNase A and metal catalyzed oxidation damage, respectively. The C-terminal thioredoxin domain is required for the nucleic acid–protein complex formation. From these results, it can be hypothesized that AtNTRC, which is known to be an electron donor of peroxiredoxin, contributes the stability of macromolecules under cold stress. - Highlights: • AtNTRC has a cryoprotective activity in vitro. • Overexpression of AtNTRC increases tolerance to freezing and cold shock stresses. • Thioredoxin domain of AtNTRC protects nucleic acids in vitro. • AtNTRC inhibits protein aggregation under freezing stress in vitro

  7. carboxylate synthase gene family in Arabidopsis, rice, grapevine

    African Journals Online (AJOL)

    Yomi

    2012-01-16

    Jan 16, 2012 ... evolutionary relationships of ACS genes in the four plant species. Chromosomal .... classification was consistent with the report from. Jakubowicz et al. ..... Analysis of the genome sequence of the flowering plant Arabidopsis ...

  8. Plastid ribosomal protein S5 plays a critical role in photosynthesis, plant development, and cold stress tolerance in arabidopsis

    Science.gov (United States)

    Plastid ribosomal proteins (RPs) are essential components for protein synthesis machinery and exert diverse roles in plant growth and development. Mutations in plastid RPs lead to a range of developmental phenotypes in plants. However, how they regulate these processes is not fully understood and th...

  9. How does a plant orchestrate defense in time and space? Using glucosinolates in Arabidopsis as case study

    DEFF Research Database (Denmark)

    Burow, Meike; Halkier, Barbara Ann

    2017-01-01

    The sessile nature of plants has caused plants to develop means to defend themselves against attacking organisms. Multiple strategies range from physical barriers to chemical warfare including pre-formed anticipins as well as phytoalexins produced only upon attack. While phytoalexins require rapid...

  10. Inter- and intracellular colonization of Arabidopsis roots by endophytic actinobacteria and the impact of plant hormones on their antimicrobial activity

    NARCIS (Netherlands)

    Meij, van der Anne; Willemse, Joost; Schneijderberg, Martinus A.; Geurts, René; Raaijmakers, Jos M.; Wezel, van Gilles P.

    2018-01-01

    Many actinobacteria live in close association with eukaryotes such as fungi, insects, animals and plants. Plant-associated actinobacteria display (endo)symbiotic, saprophytic or pathogenic life styles, and can make up a substantial part of the endophytic community. Here, we characterised endophytic

  11. Inter- and intracellular colonization of Arabidopsis roots by endophytic actinobacteria and the impact of plant hormones on their antimicrobial activity

    NARCIS (Netherlands)

    Van der Meij, Anne; Willemse, Joost; Schneijderberg, Martinus A.; Geurts, Rene; Raaijmakers, Jos; van Wezel, Gilles

    2018-01-01

    Many actinobacteria live in close association with eukaryotes like fungi, insects, animals and plants. Plant-associated actinobacteria display (endo)symbiotic, saprophytic or pathogenic life styles, and can make up a substantial part of the endophytic community. Here, we characterised endophytic

  12. SUV2, which encodes an ATR-related cell cycle checkpoint and putative plant ATRIP, is required for aluminium-dependent root growth inhibition in Arabidopsis.

    Science.gov (United States)

    Sjogren, Caroline A; Larsen, Paul B

    2017-09-01

    A suppressor mutagenesis screen was conducted in order to identify second site mutations that could reverse the extreme hypersensitivity to aluminium (Al) seen for the Arabidopsis mutant, als3-1. From this screen, it was found that a loss-of-function mutation in the previously described SUV2 (SENSITIVE TO UV 2), which encodes a putative plant ATRIP homologue that is a component of the ATR-dependent cell checkpoint response, reversed the als3-1 phenotype. This included prevention of hallmarks associated with als3-1 including Al-dependent terminal differentiation of the root tip and transition to endoreduplication. From this analysis, SUV2 was determined to be required for halting cell cycle progression and triggering loss of the quiescent centre (QC) following exposure to Al. In conjunction with this, SUV2 was found to have a similar role as ATR, ALT2 and SOG1 in Al-dependent stoppage of root growth, all of which are required for promotion of expression of a suite of genes that likely are part of an Al-dependent DNA damage transcriptional response. This work argues that these Al response factors work together to detect Al-dependent damage and subsequently activate a DNA damage response pathway that halts the cell cycle and subsequently promotes QC differentiation and entrance into endocycling. © 2017 John Wiley & Sons Ltd.

  13. Blue light alters miR167 expression and microRNA-targeted auxin response factor genes in Arabidopsis thaliana plants.

    Science.gov (United States)

    Pashkovskiy, Pavel P; Kartashov, Alexander V; Zlobin, Ilya E; Pogosyan, Sergei I; Kuznetsov, Vladimir V

    2016-07-01

    The effect of blue LED (450 nm) on the photomorphogenesis of Arabidopsis thaliana Col-0 plants and the transcript levels of several genes, including miRNAs, photoreceptors and auxin response factors (ARF) was investigated. It was observed that blue light accelerated the generative development, reduced the rosette leaf number, significantly reduced the leaf area, dry biomass and led to the disruption of conductive tissue formation. The blue LED differentially influenced the transcript levels of several phytochromes (PHY a, b, c, d, and e), cryptochromes (CRY 1 and 2) and phototropins (PHOT 1 and 2). At the same time, the blue LED significantly increased miR167 expression compared to a fluorescent lamp or white LEDs. This increase likely resulted in the enhanced transcription of the auxin response factor genes ARF4 and ARF8, which are regulated by this miRNA. These findings support the hypothesis that the effects of blue light on A. thaliana are mediated by auxin signalling pathway involving miRNA-dependent regulation of ARF gene expression. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  14. A Role for Nonsense-Mediated mRNA Decay in Plants: Pathogen Responses Are Induced in Arabidopsis thaliana NMD Mutants

    Science.gov (United States)

    Rayson, Samantha; Arciga-Reyes, Luis; Wootton, Lucie; De Torres Zabala, Marta; Truman, William; Graham, Neil; Grant, Murray; Davies, Brendan

    2012-01-01

    Nonsense-mediated mRNA decay (NMD) is a conserved mechanism that targets aberrant mRNAs for destruction. NMD has also been found to regulate the expression of large numbers of genes in diverse organisms, although the biological role for this is unclear and few evolutionarily conserved targets have been identified. Expression analyses of three Arabidopsis thaliana lines deficient in NMD reveal that the vast majority of NMD-targeted transcripts are associated with response to pathogens. Congruently, NMD mutants, in which these transcripts are elevated, confer partial resistance to Pseudomonas syringae. These findings suggest a biological rationale for the regulation of gene expression by NMD in plants and suggest that manipulation of NMD could offer a new approach for crop protection. Amongst the few non-pathogen responsive NMD-targeted genes, one potential NMD targeted signal, the evolutionarily conserved upstream open reading frame (CuORF), was found to be hugely over-represented, raising the possibility that this feature could be used to target specific physiological mRNAs for control by NMD. PMID:22384098

  15. Phytate (Inositol Hexakisphosphate in Soil and Phosphate Acquisition from Inositol Phosphates by Higher Plants. A Review

    Directory of Open Access Journals (Sweden)

    Jörg Gerke

    2015-05-01

    Full Text Available Phosphate (P fixation to the soil solid phase is considered to be important for P availability and is often attributed to the strong binding of orthophosphate anion species. However, the fixation and subsequent immobilization of inositolhexa and pentaphosphate isomers (phytate in soil is often much stronger than that of the orthosphate anion species. The result is that phytate is a main organic P form in soil and the dominating form of identifiable organic P. The reasons for the accumulation are not fully clear. Two hypothesis can be found in the literature in the last 20 years, the low activity of phytase (phosphatases in soil, which makes phytate P unavailable to the plant roots, and, on the other hand, the strong binding of phytate to the soil solid phase with its consequent stabilization and accumulation in soil. The hypothesis that low phytase activity is responsible for phytate accumulation led to the development of genetically modified plant genotypes with a higher expression of phytase activity at the root surface and research on the effect of a higher phytate activity on P acquisition. Obviously, this hypothesis has a basic assumption, that the phytate mobility in soil is not the limiting step for P acquisition of higher plants from soil phytate. This assumption is, however, not justified considering the results on the sorption, immobilization and fixation of phytate to the soil solid phase reported in the last two decades. Phytate is strongly bound, and the P sorption maximum and probably the sorption strength of phytate P to the soil solid phase is much higher, compared to that of orthophosphate P. Mobilization of phytate seems to be a promising step to make it available to the plant roots. The excretion of organic acid anions, citrate and to a lesser extend oxalate, seems to be an important way to make phytate P available to the plants. Phytase activity at the root surface seems not be the limiting step in P acquisition from phytate

  16. Formation of higher plant component microbial community in closed ecological system

    Science.gov (United States)

    Tirranen, L. S.

    2001-07-01

    Closed ecological systems (CES) place at the disposal of a researcher unique possibilities to study the role of microbial communities in individual components and of the entire system. The microbial community of the higher plant component has been found to form depending on specific conditions of the closed ecosystem: length of time the solution is reused, introduction of intrasystem waste water into the nutrient medium, effect of other component of the system, and system closure in terms of gas exchange. The higher plant component formed its own microbial complex different from that formed prior to closure. The microbial complex of vegetable polyculture is more diverse and stable than the monoculture of wheat. The composition of the components' microflora changed, species diversity decreased, individual species of bacteria and fungi whose numbers were not so great before the closure prevailed. Special attention should be paid to phytopathogenic and conditionally pathogenic species of microorganisms potentially hazardous to man or plants and the least controlled in CES. This situation can endanger creation of CES and make conjectural existence of preplanned components, man, specifically, and consequently, of CES as it is.

  17. Roles of Organic Acid Anion Secretion in Aluminium Tolerance of Higher Plants

    Science.gov (United States)

    Yang, Lin-Tong; Qi, Yi-Ping; Jiang, Huan-Xin; Chen, Li-Song

    2013-01-01

    Approximately 30% of the world's total land area and over 50% of the world's potential arable lands are acidic. Furthermore, the acidity of the soils is gradually increasing as a result of the environmental problems including some farming practices and acid rain. At mildly acidic or neutral soils, aluminium(Al) occurs primarily as insoluble deposits and is essentially biologically inactive. However, in many acidic soils throughout the tropics and subtropics, Al toxicity is a major factor limiting crop productivity. The Al-induced secretion of organic acid (OA) anions, mainly citrate, oxalate, and malate, from roots is the best documented mechanism of Al tolerance in higher plants. Increasing evidence shows that the Al-induced secretion of OA anions may be related to the following several factors, including (a) anion channels or transporters, (b) internal concentrations of OA anions in plant tissues, (d) temperature, (e) root plasma membrane (PM) H+-ATPase, (f) magnesium (Mg), and (e) phosphorus (P). Genetically modified plants and cells with higher Al tolerance by overexpressing genes for the secretion and the biosynthesis of OA anions have been obtained. In addition, some aspects needed to be further studied are also discussed. PMID:23509687

  18. 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.

  19. Reference: 398 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available modulate the photosynthetic potential of plant cells. Identification of genes required for light-induced chloroplast movement... is beginning to define the molecular machinery that controls these movement...s. In this work, we describe plastid movement impaired 2 (pmi2), a mutant in Arabidopsis (Arabi...dopsis thaliana) that displays attenuated chloroplast movements under intermediate and high light intensitie...s while maintaining a normal movement response under low light intensities. In wi

  20. Reference: 170 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available rice A et al. 2005 Mar. Plant Cell 17(3):791-803. Environmental time cues, such as photocycles (light/dark) and thermocycles...h is known about entrainment of the Arabidopsis thaliana clock to photocycles, th...e determinants of thermoperception and entrainment to thermocycles are not known. The Arabidopsis PSEUDO-RES... an oscillation after entrainment to thermocycles and to reset its clock in response to cold pulses and thus

  1. Bioavailability of nanoparticulate hematite to Arabidopsis thaliana

    International Nuclear Information System (INIS)

    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.

    2013-01-01

    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. -- 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

  2. Regulation of chloroplast number and DNA synthesis in higher plants. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Mullet, J.E.

    1995-11-10

    The long term objective of this research is to understand the process of chloroplast development and its coordination with leaf development in higher plants. This is important because the photosynthetic capacity of plants is directly related to leaf and chloroplast development. This research focuses on obtaining a detailed description of leaf development and the early steps in chloroplast development including activation of plastid DNA synthesis, changes in plastid DNA copy number, activation of chloroplast transcription and increases in plastid number per cell. The grant will also begin analysis of specific biochemical mechanisms by isolation of the plastid DNA polymerase, and identification of genetic mutants which are altered in their accumulation of plastid DNA and plastid number per cell.

  3. Molecular Characterization of the Plant Growth Promoting Bacterium Enterobacter sp. SA187 upon Contact with Arabidopsis thaliana

    KAUST Repository

    Alsharif, Wiam

    2018-01-01

    Salt stress is a severe environmental challenge in agriculture, limiting the quality and productivity of the crops around the globe. Plant growth promoting rhizobacteria (PGPR) is proposed as a friendly solution to overcome those challenges

  4. Interference of Cd2+ in functioning of the photosynthetic apparatus of higher plants

    Directory of Open Access Journals (Sweden)

    Tadeusz Baszyński

    2014-01-01

    Full Text Available The actual opinions concerning the role of Cd2+ in inhibition of photosynthesis have been reviewed. The light phase of photosynthesis, particularly the site of Cd2+ action in the photosynthetic transport chain has been given the greatest attention. Cd2+-induced inhibition of Photosystem II activity as the result of thylakoid membrane degradation has been discussed. The present studies on Cd2+-inhibited dark reactions occurring in stroma has been analysed. Attention has been drawn to the fact that the results of studies in vitro are not always compatible with the changes found in the photosynthetic apparatus of higher plants growing in a Cd2 containing medium.

  5. Protein Biochemistry and Expression Regulation of Cadmium/Zinc Pumping ATPases in the Hyperaccumulator Plants Arabidopsis halleri and Noccaea caerulescens

    Directory of Open Access Journals (Sweden)

    Seema Mishra

    2017-05-01

    Full Text Available P1B-ATPases are decisive for metal accumulation phenotypes, but mechanisms of their regulation are only partially understood. Here, we studied the Cd/Zn transporting ATPases NcHMA3 and NcHMA4 from Noccaea caerulescens as well as AhHMA3 and AhHMA4 from Arabidopsis halleri. Protein biochemistry was analyzed on HMA4 purified from roots of N. caerulescens in active state. Metal titration of NcHMA4 protein with an electrochromic dye as charge indicator suggested that HMA4 reaches maximal ATPase activity when all internal high-affinity Cd2+ binding sites are occupied. Although HMA4 was reported to be mainly responsible for xylem loading of heavy metals for root to shoot transport, the current study revealed high expression of NcHMA4 in shoots as well. Further, there were additional 20 and 40 kD fragments at replete Zn2+ and toxic Cd2+, but not at deficient Zn2+ concentrations. Altogether, the protein level expression analysis suggested a more multifunctional role of NcHMA4 than previously assumed. Organ-level transcription analysis through quantitative PCR of mRNA in N. caerulescens and A. halleri confirmed the strong shoot expression of both NcHMA4 and AhHMA4. Further, in shoots NcHMA4 was more abundant in 10 μM Zn2+ and AhHMA4 in Zn2+ deficiency. In roots, NcHMA4 was up-regulated in response to deficient Zn2+ when compared to replete Zn2+ and toxic Cd2+ treatment. In both species, HMA3 was much more expressed in shoots than in roots, and HMA3 transcript levels remained rather constant regardless of Zn2+ supply, but were up-regulated by 10 μM Cd2+. Analysis of cellular expression by quantitative mRNA in situ hybridisation showed that in A. halleri, both HMA3 and HMA4 mRNA levels were highest in the mesophyll, while in N. caerulescens they were highest in the bundle sheath of the vein. This is likely related to the different final storage sites for hyperaccumulated metals in both species: epidermis in N. caerulescens, mesophyll in A. halleri.

  6. Biochemical characterization of the triticale TsPAP1, a new type of plant prolyl aminopeptidase, and its impact on proline content and flowering time in transgenic Arabidopsis plants.

    Science.gov (United States)

    Zdunek-Zastocka, Edyta; Grabowska, Agnieszka; Branicki, Tomasz; Michniewska, Beata

    2017-07-01

    Proline aminopeptidase (PAP, EC 3.4.11.5) is the only enzyme that effectively releases proline from the N-termini of peptides. The amino acid sequence of the PAP from Triticosecale, TsPAP1, comprises conserved regions, characteristic of the monomeric forms of PAP found in bacteria but not yet identified in plants. Therefore, we aimed to obtain and biochemically characterize the TsPAP1 protein. The recombinant TsPAP1 protein was received through heterologous expression of the TsPAP1 coding sequence in a bacterial expression system and purified with affinity chromatography. Gel filtration chromatography and SDS electrophoresis revealed that TsPAP1 is a monomer with a molecular mass of 37.5 kDa. TsPAP1 prefers substrates with proline at the N-terminus but is also capable of hydrolyzing β-naphthylamides of hydroxyproline and alanine. Among the peptides tested, the most preferred were di- and tripeptides, especially those with glycine in the Y position. The use of diagnostic inhibitors indicated that TsPAP1 is a serine peptidase; however, further characterization revealed that the SH residues are also important for maintaining its activity. To examine the role of TsPAP1 under physiological conditions, we developed transgenic Arabidopsis plants overexpressing TsPAP1. Compared with wild-type plants, the transgenic lines accumulated more proline, flowered an average of 3.5 days earlier, and developed more siliques than did untransformed controls. Our paper is the first to describe the biochemical properties of a novel monomeric plant PAP and contributes to the functional characterization of PAP proteins in plants. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  7. Sucrose mimics the light induction of Arabidopsis nitrate reductase gene transcription

    DEFF Research Database (Denmark)

    Cheng, Chi-Lien; Acedo, Gregoria N; Kristensen, Michael

    1992-01-01

    can replace light in eliciting an increase of nitrate reductase mRNA accumulation in dark-adapted green Arabidopsis plants. We show further that sucrose alone is sufficient for the full expression of nitrate reductase genes in etiolated Arabidopsis plants. Finally, using a reporter gene, we show......Nitrate reductase, the first enzyme in nitrate assimilation, is located at the crossroad of two energy-consuming pathways: nitrate assimilation and carbon fixation. Light, which regulates the expression of many higher-plant carbon fixation genes, also regulates nitrate reductase gene expression....... Located in the cytosol, nitrate reductase obtains its reductant not from photosynthesis but from carbohydrate catabolism. This relationship prompted us to investigate the indirect role that light might play, via photosynthesis, in the regulation of nitrate reductase gene expression. We show that sucrose...

  8. Protein Biochemistry and Expression Regulation of Cadmium/Zinc Pumping ATPases in the Hyperaccumulator Plants Arabidopsis halleri and Noccaea caerulescens

    Czech Academy of Sciences Publication Activity Database

    Mishra, S.; Mishra, Archana; Küpper, Hendrik

    2017-01-01

    Roč. 8, May 22 (2017), č. článku 835. ISSN 1664-462X R&D Projects: GA MŠk EF15_003/0000336 Institutional support: RVO:60077344 Keywords : cellular compartmentation * zinc homeostasis * cadmium * metal hyperaccumulator plants Subject RIV: CE - Biochemistry OBOR OECD: Biochemistry and molecular biology Impact factor: 4.298, year: 2016

  9. Identification an characterization of QTL underlying whole plant physiology in Arabidopsis taliana: 13C, stomatal conduction and transpiration efficiency

    NARCIS (Netherlands)

    Juenger, T.E.; McKay, J.K.; Hausmann, N.; Keurentjes, J.J.B.; Sen, S.; Stowe, K.A.; Dawson, T.E.; Simms, E.L.; Richards, J.H.

    2005-01-01

    Water limitation is one of the most important factors limiting crop productivity world-wide and has likely been an important selective regime influencing the evolution of plant physiology. Understanding the genetic and physiological basis of drought adaptation is therefore important for improving

  10. Reference: 749 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available former mutant had decreased electron transport rates, a lower DeltapH gradient across the grana membranes, r...the PSII particles of these plants were organized in unusual two-dimensional arrays in the grana membranes. ...d the electron transport rate in grana membranes of Arabidopsis. 4 1012-28 18381925 2008 Apr The Plant cell

  11. Reference: 169 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available e M et al. 2005 Mar. Plant J. 41(5):744-54. The recessive Arabidopsis thalianafumonisin B1-resistant (fbr6) ...opment and sensitivity to fumonisin B1. 5 744-54 15703061 2005 Mar The Plant journal Liang Xinwen|Nekl Emily R|Stiers Justin J|Stone Julie M

  12. Reference: 632 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available Ludmila et al. 2007 Sep. Plant J. 51(5):874-85. One of the earliest responses of plants to environmental str...elopment in reaction to adverse environmental conditions. We show that the AtCHR12 chromatin-remodeling gene...R12 mediates temporary growth arrest in Arabidopsis thaliana upon perceiving environmental

  13. Consequences of variation in plant defense for biodiversity at higher trophic levels

    NARCIS (Netherlands)

    Poelman, E.H.; Loon, van J.J.A.; Dicke, M.

    2008-01-01

    Antagonistic interactions between insect herbivores and plants impose selection on plants to defend themselves against these attackers. Although selection on plant defense traits has typically been studied for pairwise plant¿attacker interactions, other community members of plant-based food webs are

  14. Photorepair mutants of Arabidopsis

    International Nuclear Information System (INIS)

    Jiang, C.Z.; Yee, J.; Mitchell, D.L.; Britt, A.B.

    1997-01-01

    UV radiation induces two major DNA damage products, the cyclobutane pyrimidine dimer (CPD) and, at a lower frequency, the pyrimidine (6-4) pyrimidinone dimer (6-4 product). Although Escherichia coli and Saccharomyces cerevisiae produce a CPD-specific photolyase that eliminates only this class of dimer, Arabidopsis thaliana, Drosophila melanogaster, Crotalus atrox, and Xenopus laevis have recently been shown to photoreactivate both CPDs and 6-4 products. We describe the isolation and characterization of two new classes of mutants of Arabidopsis, termed uvr2 and uvr3, that are defective in the photoreactivation of CPDs and 6-4 products, respectively. We demonstrate that the CPD photolyase mutation is genetically linked to a DNA sequence encoding a type II (metazoan) CPD photolyase. In addition, we are able to generate plants in which only CPDs or 6-4 products are photoreactivated in the nuclear genome by exposing these mutants to UV light and then allowing them to repair one or the other class of dimers. This provides us with a unique opportunity to study the biological consequences of each of these two major UV-induced photoproducts in an intact living system

  15. Arabidopsis peroxisome proteomics

    Directory of Open Access Journals (Sweden)

    John D. Bussell

    2013-04-01

    Full Text Available The analytical depth of investigation of the peroxisomal proteome of the model plant Arabidopsis thaliana has not yet reached that of other major cellular organelles such as chloroplasts or mitochondria. This is primarily due to the difficulties associated with isolating and obtaining purified samples of peroxisomes from Arabidopsis. So far only a handful of research groups have been successful in obtaining such fractions. To make things worse, enriched peroxisome fractions frequently suffer from significant organellar contamination, lowering confidence in localization assignment of the identified proteins. As with other cellular compartments, identification of peroxisomal proteins forms the basis for investigations of the dynamics of the peroxisomal proteome. It is therefore not surprising that, in terms of functional analyses by proteomic means, there remains a considerable gap between peroxisomes and chloroplasts or mitochondria. Alternative strategies are needed to overcome the obstacle of hard-to-obtain organellar fractions. This will help to close the knowledge gap between peroxisomes and other organelles and provide a full picture of the physiological pathways shared between organelles. In this review we briefly summarize the status quo and discuss some of the methodological alternatives to classic organelle proteomic approaches.

  16. Arabidopsis protocols

    National Research Council Canada - National Science Library

    Martínez-Zapater, José M; Salinas, Julio

    1998-01-01

    ... the interest of geneticists and molecular biologists, not only from the plant field, but from other research fields needing a novel model system. In recent years, high expectations for Plant Biotechnology in the next century, together with the need for basic information in every area of plant biology, have served to mobilize resources and orient much new...

  17. Survival and interaction of Escherichia coli O104:H4 on Arabidopsis thaliana and lettuce (Lactuca sativa) in comparison to E. coli O157:H7: Influence of plant defense response and bacterial capsular polysaccharide.

    Science.gov (United States)

    Jang, Hyein; Matthews, Karl R

    2018-06-01

    Shiga toxin-producing Escherichia coli (STEC) has been associated with illnesses and outbreaks linked to fresh vegetables, prompting a growing public health concern. Most studies regarding interactions of STEC on fresh produce focused on E. coli O157:H7. Limited information is available about survival or fitness of E. coli O104:H4, non-O157 pathogen that was linked to one of the largest outbreaks of hemolytic uremic syndrome in 2011. In this study, survival of E. coli O104:H4 was evaluated on Arabidopsis thaliana plant and lettuce for 5 days compared with E. coli O157:H7, and expression of pathogenesis-realted gene (PR1; induction of plant defense response) was examined by reverse transcription quantitative PCR, and potential influence of capsular polysaccharide (CPS) on the bacterial fitness on plant was investigated. Populations of E. coli O104:H4 strains (RG1, C3493, and LpfA) on Arabidopsis and lettuce were significantly (P E. coli O157:H7 strains (7386 and sakai) at day 5 post-inoculation, indicating E. coli O104:H4 may have better survival ability on the plants. In addition, the E. coli O104:H4 strains produced significantly (P E. coli O157:H7 strains. RG1 strain (1.5-fold) initiated significantly (P E. coli O157:H7 strains 7386 (2.9-fold) and sakai (2.7-fold). Collectively, the results in this study suggests that different level of CPS production and plant defense response initiated by each STEC strain might influence the bacterial survival or persistence on plants. The present study provides better understanding of survival behavior of STEC, particularly E. coli O104:H4, using a model plant and vegetable under pre-harvest conditions with plant defense response. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. Stochastic gene expression in Arabidopsis thaliana.

    Science.gov (United States)

    Araújo, Ilka Schultheiß; Pietsch, Jessica Magdalena; Keizer, Emma Mathilde; Greese, Bettina; Balkunde, Rachappa; Fleck, Christian; Hülskamp, Martin

    2017-12-14

    Although plant development is highly reproducible, some stochasticity exists. This developmental stochasticity may be caused by noisy gene expression. Here we analyze the fluctuation of protein expression in Arabidopsis thaliana. Using the photoconvertible KikGR marker, we show that the protein expressions of individual cells fluctuate over time. A dual reporter system was used to study extrinsic and intrinsic noise of marker gene expression. We report that extrinsic noise is higher than intrinsic noise and that extrinsic noise in stomata is clearly lower in comparison to several other tissues/cell types. Finally, we show that cells are coupled with respect to stochastic protein expression in young leaves, hypocotyls and roots but not in mature leaves. Our data indicate that stochasticity of gene expression can vary between tissues/cell types and that it can be coupled in a non-cell-autonomous manner.

  19. Plant phosphatidylcholine-hydrolyzing phospholipases C NPC3 and NPC4 with roles in root development and brassinolide signaling in Arabidopsis thaliana.

    Science.gov (United States)

    Wimalasekera, Rinukshi; Pejchar, Premysl; Holk, André; Martinec, Jan; Scherer, Günther F E

    2010-05-01

    Phosphatidylcholine-hydrolyzing phospholipase C (PC-PLC) catalyzes the hydrolysis of phosphatidylcholine (PC) to generate phosphocholine and diacylglycerol (DAG). PC-PLC has a long tradition in animal signal transduction to generate DAG as a second messenger besides the classical phosphatidylinositol splitting phospholipase C (PI-PLC). Based on amino acid sequence similarity to bacterial PC-PLC, six putative PC-PLC genes (NPC1 to NPC6) were identified in the Arabidopsis genome. RT-PCR analysis revealed overlapping expression pattern of NPC genes in root, stem, leaf, flower, and silique. In auxin-treated P(NPC3):GUS and P(NPC4):GUS seedlings, strong increase of GUS activity was visible in roots, leaves, and shoots and, to a weaker extent, in brassinolide-treated (BL) seedlings. P(NPC4):GUS seedlings also responded to cytokinin with increased GUS activity in young leaves. Compared to wild-type, T-DNA insertional knockouts npc3 and npc4 showed shorter primary roots and lower lateral root density at low BL concentrations but increased lateral root densities in response to exogenous 0.05-1.0 μM BL. BL-induced expression of TCH4 and LRX2, which are involved in cell expansion, was impaired but not impaired in repression of CPD, a BL biosynthesis gene, in BL-treated npc3 and npc4. These observations suggest NPC3 and NPC4 are important in BL-mediated signaling in root growth. When treated with 0.1 μM BL, DAG accumulation was observed in tobacco BY-2 cell cultures labeled with fluorescent PC as early as 15 min after application. We hypothesize that at least one PC-PLC is a plant signaling enzyme in BL signal transduction and, as shown earlier, in elicitor signal transduction.

  20. Biochemical studies on the effect of fluoride on higher plants. II. The effect of fluoride on sucrose-synthesizing enzymes from higher plants

    Energy Technology Data Exchange (ETDEWEB)

    Yang, S F; Miller, G W

    1963-01-01

    A study was initiated to characterize the properties of partially purified phosphoglucomutase, uridine diphosphate glucose pyrophosphorylase and uridine diphosphate glucose-fructose transglucosyalse, from various plant sources, with respect to activation by metal ions and inhibition by fluoride. Of the three enzymes studied, only phosphoglucomutase was very sensitive to fluoride. It is likely that the inhibition of sucrose synthesis in fluoride-fumigated plants might be due to the inhibition of phosphoglucomutase, which plays an important role in carbohydrate metabolism. However, at present, there is insufficient evidence to show the inhibition of phosphoglucomutase in vivo by fumigation with hydrogen fluoride.

  1. Fate of induced mutations in higher plants with special emphasis on sexually reproducing species

    International Nuclear Information System (INIS)

    Cornu, Andre

    1978-01-01

    A mutation induced in a plant somatic cell has to overcome quite many difficulties before being isolated and utilized as a marker in a mutated line. If induced in a meristem, three conditions must be fulfilled for the mutation to be transmitted to the subsequent generation: it must be compatible with normal cell multiplication, it must be located in a cell mass that will provide an inflorescence, and it must be in the sporogenetic layer (t2). Under these conditions, or if it is induced in a gamete or in a zygote, the mutation enters a first cycle of sexual reproduction. Meiosis and the subsequent haploid phase constitute severe screening steps for many chromosome aberrations. Studies on Petunia performed by means of marker genes show that male and female gametic viabilities are drastically impaired by deletions. However, a deficient chromosome can be transmitted when the losss of information is compensated for by homologous information as, for example, diploid gametes from tetraploids or disomic gametes resulting from non-disjunction. If partial or complete sterility, whether sporo- or gametophytic, is avoided, then the mutation can be transmitted to the next generation in heterozygous state. When becoming homozygous, the mutation may have effects such that its use can be most difficult. This is the case when this mutation causes rather early lethality or severe sterility. Thus, in higher plants, one faces several cases of powerful and efficient selection against mutations. On the basis of experiments carried out on Petunia, the per locus mutation rate of practical interest ranges between I and 5/10000M 1 plants. Practical conclusions are drawn about which organ should be treated, which mutagen at what dose should be used according to the scope of the research undertaken [fr

  2. Enhanced Thermostability of Arabidopsis Rubisco activase improves photosynthesis and growth rates under moderate heat stress.

    Science.gov (United States)

    Kurek, Itzhak; Chang, Thom Kai; Bertain, Sean M; Madrigal, Alfredo; Liu, Lu; Lassner, Michael W; Zhu, Genhai

    2007-10-01

    Plant photosynthesis declines when the temperature exceeds its optimum range. Recent evidence indicates that the reduction in photosynthesis is linked to ribulose-1,5-bis-phosphate carboxylase/oxygenase (Rubisco) deactivation due to the inhibition of Rubisco activase (RCA) under moderately elevated temperatures. To test the hypothesis that thermostable RCA can improve photosynthesis under elevated temperatures, we used gene shuffling technology to generate several Arabidopsis thaliana RCA1 (short isoform) variants exhibiting improved thermostability. Wild-type RCA1 and selected thermostable RCA1 variants were introduced into an Arabidopsis RCA deletion (Deltarca) line. In a long-term growth test at either constant 26 degrees C or daily 4-h 30 degrees C exposure, the transgenic lines with the thermostable RCA1 variants exhibited higher photosynthetic rates, improved development patterns, higher biomass, and increased seed yields compared with the lines expressing wild-type RCA1 and a slight improvement compared with untransformed Arabidopsis plants. These results provide clear evidence that RCA is a major limiting factor in plant photosynthesis under moderately elevated temperatures and a potential target for genetic manipulation to improve crop plants productivity under heat stress conditions.

  3. Plasmodesmata without callose and calreticulin in higher plants - open channels for fast symplastic transport?

    Directory of Open Access Journals (Sweden)

    Kirill N. Demchenko

    2014-03-01

    Full Text Available Plasmodesmata (PD represent membrane-lined channels that link adjacent plant cells across the cell wall. PD of higher plants contain a central tube of endoplasmic reticulum called desmotubule. Membrane and lumen proteins seem to be able to move through the desmotubule, but most transport processes through PD occur through the cytoplasmic annulus (Brunkard et al., 2013. Calreticulin (CRT, a highly conserved Ca2+-binding protein found in all multi-cellular eukaryotes, predominantly located in the ER, was shown to localize to PD, though not all PD accumulate CRT. In nitrogen fixing actinorhizal root nodules of the Australian tree Casuarina glauca, the primary walls of infected cells containing the microsymbiont become lignified upon infection. TEM analysis of these nodules showed that during the differentiation of infected cells, PD connecting infected cells, and connecting infected and adjacent uninfected cells, were reduced in number as well as diameter (Schubert et al., 2013. In contrast with PD connecting young infected cells, and most PD connecting mature infected and adjacent uninfected cells, PD connecting mature infected cells did not accumulate CRT. Furthermore, as shown here, these PD were not associated with callose, and based on their diameter, they probably had lost their desmotubules. We speculate that either this is a slow path to PD degradation, or that the loss of callose accumulation and presumably also desmotubules leads to the PD becoming open channels and improves metabolite exchange between cells.

  4. Effects of fluoride on mitochondrial activity in higher plants. [Glycine max, Zea mays

    Energy Technology Data Exchange (ETDEWEB)

    Miller, J E; Miller, G W

    1974-01-01

    The effects of fluoride on respiration of plant tissue and mitochondria were investigated. Fumigation of young soybean plants (Glycine max Merr. cm. Hawkeye) with 9-12 ..mu..g x m/sup -3/ HF caused a stimulation of respiration at about 2 days of treatment followed by inhibition 2 days later. Mitochondria isolated from the stimulated tissue had higher respiration rates, greater ATPase activity, and lower P/O ratios, while in mitochondria from inhibited tissue, all three were reduced. Treatment of etiolated soybean hypocotyl sections in Hoagland's solution containing KF for 3 to 10 h only resulted in inhibition of respiration. Mitochondria isolated from this tissue elicited increased respiration rates with malate as substrate and inhibited respiration with succinate. With both substrates respiratory control and ADP/O ratios were decreased. Direct treatment of mitochondria from etiolated soybean hypocotyl tissue with fluoride resulted in inhibition of state 3 respiration and lower ADP/O ratios with the substrates succinate, malate, and NADH. Fluoride was also found to increase the amount of osmotically induced swelling and cause a more rapid leakage of protein with mitochondria isolated from etiolated corn shoots (Zea mays L. cv. Golden Cross Bantam). 40 references, 1 figure, 5 tables.

  5. The use of sulphite solutions for studying the effects of SO2 on higher plants

    International Nuclear Information System (INIS)

    Garsed, S.G.

    1981-01-01

    The effects of sulphite concentration and pH on 14 CO 2 fixation or the uptake of 35 S by needle segments of Pinus sylvestris were studied in factorial experiments. In addition, changes in the chemical composition of the sulphite solutions during the experiment were measured. Uptake of 14 CO 2 was increased and standard errors decreased by incorporating 1.0 to 10 ppm of Tween 80 into the solutions used. Inhibition of 14 CO 2 fixation by sulphite was significantly greater at low pH and high sulphite concentration, with a significant interaction. Uptake of Na 2 35 SO 3 was greater at low pH and was linear with respect to the concentration of Na 2 SO 3 carrier added between 10 -3 and 10 -4 M. In the absence of carrier, recovery of 35 S at the end of the experiment was reduced. Oxidation of the sulphite solutions was rapid at high pH and low concentration, with a significant interaction. It was also accelerated by the presence of plant material. The use of sulphite solutions to predict responses of higher plants to SO 2 is discussed. (author)

  6. Studies on the application of radiation for genetic transformation in higher plants

    International Nuclear Information System (INIS)

    Lee, Young Il; Song, Hi Sup; Kim, Jae Sung; Shin, In Chul; Lee, Sang Jae; Lee, Ki Woon; Lim, Yong Taek

    1992-02-01

    Present research carried out to develop the radiation application on the mutation research of genetic engineering. Some variants selected in M1 generation derived from the plantlet by the nodal stem culture of three potato cultivars irradiated with gamma rays, and the optimum dosage for mutation induction was revealed the range of 30 - 50 Gy of gamma ray. In the rice anther culture of the plant irradiated with gamma rays at different developmental stage of microspore, the haploidy callus formation rates were much higher in gamma ray irradiated anthers than those of non-irradiated, and the occurrence of a typical pollen was significantly increased up to 47% in the anthers irradiated with 30 Gy of gamma ray compared with 11% of non-irradiated anthers at the stage of pollen mother cell. A lot of variants were selected in rice, soybean, perilla and red pepper irradiated with gamma rays for breeding of earliness, short culm, high yielding and disease resistant mutant. (Author)

  7. Electric current precedes emergence of a lateral root in higher plants.

    Science.gov (United States)

    Hamada, S; Ezaki, S; Hayashi, K; Toko, K; Yamafuji, K

    1992-10-01

    Stable electrochemical patterns appear spontaneously around roots of higher plants and are closely related to growth. An electric potential pattern accompanied by lateral root emergence was measured along the surface of the primary root of adzuki bean (Phaseolus angularis) over 21 h using a microelectrode manipulated by a newly developed apparatus. The electric potential became lower at the point where a lateral root emerged. This change preceded the emergence of the lateral root by about 10 h. A theory is presented for calculating two-dimensional patterns of electric potential and electric current density around the primary root (and a lateral root) using only data on the one-dimensional electric potential measured near the surface of the primary root. The development of the lateral root inside the primary root is associated with the influx of electric current of about 0.7 muA.cm(-2) at the surface.

  8. Overexpression of Late Embryogenesis Abundant 14 enhances Arabidopsis salt stress tolerance

    Energy Technology Data Exchange (ETDEWEB)

    Jia, Fengjuan, E-mail: jfj.5566@163.com; Qi, Shengdong, E-mail: zisexanwu@163.com; Li, Hui, E-mail: 332453593@qq.com; Liu, Pu, E-mail: banbaokezhan@163.com; Li, Pengcheng, E-mail: lpcsdau@163.com; Wu, Changai, E-mail: cawu@sdau.edu.cn; Zheng, Chengchao, E-mail: cczheng@sdau.edu.cn; Huang, Jinguang, E-mail: jghuang@sdau.edu.cn

    2014-11-28

    Highlights: • It is the first time to investigate the biological function of AtLEA14 in salt stress response. • AtLEA14 enhances the salt stress tolerance both in Arabidopsis and yeast. • AtLEA14 responses to salt stress by stabilizing AtPP2-B11, an E3 ligase, under normal or salt stress conditions. - Abstract: Late embryogenesis abundant (LEA) proteins are implicated in various abiotic stresses in higher plants. In this study, we identified a LEA protein from Arabidopsis thaliana, AtLEA14, which was ubiquitously expressed in different tissues and remarkably induced with increased duration of salt treatment. Subcellular distribution analysis demonstrated that AtLEA14 was mainly localized in the cytoplasm. Transgenic Arabidopsis and yeast overexpressing AtLEA14 all exhibited enhanced tolerance to high salinity. The transcripts of salt stress-responsive marker genes (COR15a, KIN1, RD29B and ERD10) were overactivated in AtLEA14 overexpressing lines compared with those in wild type plants under normal or salt stress conditions. In vivo and in vitro analysis showed that AtLEA14 could effectively stabilize AtPP2-B11, an important E3 ligase. These results suggested that AtLEA14 had important protective functions under salt stress conditions in Arabidopsis.

  9. Overexpression of Late Embryogenesis Abundant 14 enhances Arabidopsis salt stress tolerance

    International Nuclear Information System (INIS)

    Jia, Fengjuan; Qi, Shengdong; Li, Hui; Liu, Pu; Li, Pengcheng; Wu, Changai; Zheng, Chengchao; Huang, Jinguang

    2014-01-01

    Highlights: • It is the first time to investigate the biological function of AtLEA14 in salt stress response. • AtLEA14 enhances the salt stress tolerance both in Arabidopsis and yeast. • AtLEA14 responses to salt stress by stabilizing AtPP2-B11, an E3 ligase, under normal or salt stress conditions. - Abstract: Late embryogenesis abundant (LEA) proteins are implicated in various abiotic stresses in higher plants. In this study, we identified a LEA protein from Arabidopsis thaliana, AtLEA14, which was ubiquitously expressed in different tissues and remarkably induced with increased duration of salt treatment. Subcellular distribution analysis demonstrated that AtLEA14 was mainly localized in the cytoplasm. Transgenic Arabidopsis and yeast overexpressing AtLEA14 all exhibited enhanced tolerance to high salinity. The transcripts of salt stress-responsive marker genes (COR15a, KIN1, RD29B and ERD10) were overactivated in AtLEA14 overexpressing lines compared with those in wild type plants under normal or salt stress conditions. In vivo and in vitro analysis showed that AtLEA14 could effectively stabilize AtPP2-B11, an important E3 ligase. These results suggested that AtLEA14 had important protective functions under salt stress conditions in Arabidopsis

  10. Concepts, strategies and potentials using hypo-g and other features of the space environment for commercialization using higher plants

    Science.gov (United States)

    Krikorian, A. D.

    1985-01-01

    Opportunities for releasing, capturing, constructing and/or fixing the differential expressions or response potentials of the higher plant genome in the hypo-g environment for commercialization are explored. General strategies include improved plant-growing, crop and forestry production systems which conserve soil, water, labor and energy resources, and nutritional partitioning and mobilization of nutrients and synthates. Tissue and cell culture techniques of commercial potential include the growing and manipulation of cultured plant cells in vitro in a bioreactor to produce biologicals and secondary plants of economic value. The facilitation of plant breeding, the cloning of specific pathogen-free materials, the elimination of growing point or apex viruses, and the increase of plant yield are other O-g applications. The space environment may be advantageous in somatic embryogenesis, the culture of alkaloids, and the development of completely new crop plant germ plasm.

  11. Glufosinate ammonium selection of transformed Arabidopsis.

    Science.gov (United States)

    Weigel, Detlef; Glazebrook, Jane

    2006-12-01

    INTRODUCTIONOne of the most commonly used markers for the selection of transgenic Arabidopsis is resistance to glufosinate ammonium, an herbicide that is sold under a variety of trade names including Basta and Finale. Resistance to glufosinate ammonium is conferred by the bacterial bialophos resistance gene (BAR) encoding the enzyme phosphinotricin acetyl transferase (PAT). This protocol describes the use of glufosinate ammonium to select transformed Arabidopsis plants. The major advantage of glufosinate ammonium selection is that it can be performed on plants growing in soil and does not require the use of sterile techniques.

  12. The next generation of training for Arabidopsis researchers: bioinformatics and quantitative biology

    Science.gov (United States)

    It has been more than 50 years since Arabidopsis (Arabidopsis thaliana) was first introduced as a model organism to understand basic processes in plant biology. A well-organized scientific community has used this small reference plant species to make numerous fundamental plant biology discoveries (P...

  13. Gene expression in response to cryoprotectant and liquid nitrogen exposure in Arabidopsis shoot tips

    Science.gov (United States)

    Arabidopsis thaliana is an ideal model system to study plant cryopreservation at the molecular level. We have developed reliable cryopreservation methods for Arabidopsis shoot tips using Plant Vitrification Solution 2 and Plant Vitrification Solution 3 (PVS3) cryoprotectants. We have made use of th...

  14. Proteomic Dissection of the Mitochondrial DNA Metabolism Apparatus in Arabidopsis

    Energy Technology Data Exchange (ETDEWEB)

    SAlly A. Mackenzie

    2004-01-06

    This study involves the investigation of nuclear genetic components that regulate mitochondrial genome behavior in higher plants. The approach utilizes the advanced plant model system of Arabidopsis thaliana to identify and functionally characterize multiple components of the mitochondrial DNA replication, recombination and mismatch repair system and their interaction partners. The rationale for the research stems from the central importance of mitochondria to overall cellular metabolism and the essential nature of the mitochondrial genome to mitochondrial function. Relatively little is understood about mitochondrial DNA maintenance and transmission in higher eukaryotes, and the higher plant mitochondrial genome displays unique properties and behavior. This investigation has revealed at least three important properties of plant mitochondrial DNA metabolism components. (1) Many are dual targeted to mitochondrial and chloroplasts by novel mechanisms, suggesting that the mitochondria a nd chloroplast share their genome maintenance apparatus. (2)The MSH1 gene, originating as a component of mismatch repair, has evolved uniquely in plants to participate in differential replication of the mitochondrial genome. (3) This mitochondrial differential replication process, termed substoichiometric shifting and also involving a RecA-related gene, appears to represent an adaptive mechanism to expand plant reproductive capacity and is likely present throughout the plant kingdom.

  15. Optimization of animal manure vermicomposting based on biomass production of earthworms and higher plants.

    Science.gov (United States)

    Borges, Yan V; Alves, Luciano; Bianchi, Ivan; Espíndola, Jonas C; Oliveira, Juahil M De; Radetski, Claudemir M; Somensi, Cleder A

    2017-11-02

    The goal of this study was to optimize the mixture of swine manure (SM) and cattle manure (CM) used in the vermicomposting process, seeking to increase the manure biodegradation rate and enhance the biomass production of both earthworms and higher plants. To achieve this goal, physico-chemical parameters were determined to assess the final compost quality after 50 days of vermicomposting. The different manure ratios used to produce the composts (C) were as follows (SM:CM, % m/m basis): C1 100:0, C2 (75:25), C3 (50:50), C4 (25:75), and C5 (0:100). In addition, the earthworm biomass and the phytoproductivity of lettuce (Lactuca sativa L.) plants grown in mixtures (1:1) of natural soil and the most viable vermicomposts were investigated. The C1 and C2 compost compositions were associated with high earthworm mortality rates. The C3 compost provided the highest mineral concentrations and C5 showed the highest lettuce yield (wet biomass). The results verify that stabilized cattle manure is an excellent substrate for the vermicomposting process and that fresh swine manure must be mixed with pre-stabilized cattle manure to ensure an optimized vermicomposting process, which must be controlled in terms of temperature and ammonia levels. It is concluded that small livestock farmers could add value to swine manure by applying the vermicomposting process, without the need for high investments and with a minimal requirement for management of the biodegradation process. These are important technical aspects to be considered when circular economy principles are applied to small farms.

  16. The invasive wetland plant Alternanthera philoxeroides shows a higher tolerance to waterlogging than its native Congener Alternanthera sessilis.

    Directory of Open Access Journals (Sweden)

    Yue Chen

    Full Text Available Plant invasion is one of the major threats to natural ecosystems. Phenotypic plasticity is considered to be important for promoting plant invasiveness. High tolerance of stress can also increase survival of invasive plants in adverse habitats. Limited growth and conservation of carbohydrate are considered to increase tolerance of flooding in plants. However, few studies have examined whether invasive species shows a higher phenotypic plasticity in response to waterlogging or a higher tolerance of waterlogging (lower plasticity than native species. We conducted a greenhouse experiment to compare the growth and morphological and physiological responses to waterlogging of the invasive, clonal, wetland species Alternanthera philoxeroides with those of its co-occurring, native, congeneric, clonal species Alternanthera sessilis. Plants of A. philoxeroides and A. sessilis were subjected to three treatments (control, 0 and 60 cm waterlogging. Both A. philoxeroides and A. sessilis survived all treatments. Overall growth was lower in A. philoxeroides than in A. sessilis, but waterlogging negatively affected the growth of A. philoxeroides less strongly than that of A. sessilis. Alternanthera philoxeroides thus showed less sensitivity of growth traits (lower plasticity and higher waterlogging tolerance. Moreover, the photosynthetic capacity of A. philoxeroides was higher than that of A. sessilis during waterlogging. Alternanthera philoxeroides also had higher total non-structural and non-soluble carbohydrate concentrations than A. sessilis at the end of treatments. Our results suggest that higher tolerance to waterlogging and higher photosynthetic capacity may partly explain the invasion success of A. philoxeroides in wetlands.

  17. Early herbivore alert matters: plant-mediated effects of egg deposition on higher trophic levels benefit plant fitness

    NARCIS (Netherlands)

    Pashalidou, F.G.; Frago, E.; Griese, E.; Poelman, E.H.; Loon, van J.J.A.; Dicke, M.; Fatouros, N.E.

    2015-01-01

    Induction of plant defences, specifically in response to herbivore attack, can save costs that would otherwise be needed to maintain defences even in the absence of herbivores. However, plants may suffer considerable damage during the time required to mount these defences against an attacker. This

  18. Field Guide to Plant Model Systems

    OpenAIRE

    Chang, Caren; Bowman, John L.; Meyerowitz, Elliot M.

    2016-01-01

    For the past several decades, advances in plant development, physiology, cell biology, and genetics have relied heavily on the model (or reference) plant Arabidopsis thaliana. Arabidopsis resembles other plants, including crop plants, in many but by no means all respects. Study of Arabidopsis alone provides little information on the evolutionary history of plants, evolutionary differences between species, plants that survive in different environments, or plants that access nutrients and photo...

  19. An allele of Arabidopsis COI1 with hypo- and hypermorphic phenotypes in plant growth, defence and fertility.

    Directory of Open Access Journals (Sweden)

    Albor Dobón

    Full Text Available Resistance to biotrophic pathogens is largely dependent on the hormone salicylic acid (SA while jasmonic acid (JA regulates resistance against necrotrophs. JA negatively regulates SA and is, in itself, negatively regulated by SA. A key component of the JA signal transduction pathway is its receptor, the COI1 gene. Mutations in this gene can affect all the JA phenotypes, whereas mutations in other genes, either in JA signal transduction or in JA biosynthesis, lack this general effect. To identify components of the part of the resistance against biotrophs independent of SA, a mutagenised population of NahG plants (severely depleted of SA was screened for suppression of susceptibility. The screen resulted in the identification of intragenic and extragenic suppressors, and the results presented here correspond to the characterization of one extragenic suppressor, coi1-40. coi1-40 is quite different from previously described coi1 alleles, and it represents a strategy for enhancing resistance to biotrophs with low levels of SA, likely suppressing NahG by increasing the perception to the remaining SA. The phenotypes of coi1-40 lead us to speculate about a modular function for COI1, since we have recovered a mutation in COI1 which has a number of JA-related phenotypes reduced while others are equal to or above wild type levels.

  20. A Lipid Transfer Protein Increases the Glutathione Content and Enhances Arabidopsis Resistance to a Trichothecene Mycotoxin.

    Directory of Open Access Journals (Sweden)

    John E McLaughlin

    Full Text Available Fusarium head blight (FHB or scab is one of the most important plant diseases worldwide, affecting wheat, barley and other small grains. Trichothecene mycotoxins such as deoxynivalenol (DON accumulate in the grain, presenting a food safety risk and health hazard to humans and animals. Despite considerable breeding efforts, highly resistant wheat or barley cultivars are not available. We screened an activation tagged Arabidopsis thaliana population for resistance to trichothecin (Tcin, a type B trichothecene in the same class as DON. Here we show that one of the resistant lines identified, trichothecene resistant 1 (trr1 contains a T-DNA insertion upstream of two nonspecific lipid transfer protein (nsLTP genes, AtLTP4.4 and AtLTP4.5. Expression of both nsLTP genes was induced in trr1 over 10-fold relative to wild type. Overexpression of AtLTP4.4 provided greater resistance to Tcin than AtLTP4.5 in Arabidopsis thaliana and in Saccharomyces cerevisiae relative to wild type or vector transformed lines, suggesting a conserved protection mechanism. Tcin treatment increased reactive oxygen species (ROS production in Arabidopsis and ROS stain was associated with the chloroplast, the cell wall and the apoplast. ROS levels were attenuated in Arabidopsis and in yeast overexpressing AtLTP4.4 relative to the controls. Exogenous addition of glutathione and other antioxidants enhanced resistance of Arabidopsis to Tcin while the addition of buthionine sulfoximine, an inhibitor of glutathione synthesis, increased sensitivity, suggesting that resistance was mediated by glutathione. Total glutathione content was significantly higher in Arabidopsis and in yeast overexpressing AtLTP4.4 relative to the controls, highlighting the importance of AtLTP4.4 in maintaining the redox state. These results demonstrate that trichothecenes cause ROS accumulation and overexpression of AtLTP4.4 protects against trichothecene-induced oxidative stress by increasing the glutathione

  1. DsSWEET17, a Tonoplast-Localized Sugar Transporter from Dianthus spiculifolius, Affects Sugar Metabolism and Confers Multiple Stress Tolerance in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Aimin Zhou

    2018-05-01

    Full Text Available Plant SWEETs (Sugars Will Eventually be Exported Transporters affect the growth of plants by regulating the transport of sugar from source to sink and its intracellular transport between different organelles. In this study, DsSWEET17 from Dianthus spiculifolius was identified and characterized. Real-time quantitative PCR analysis revealed that the expression of DsSWEET17 was affected by exogenous application of fructose and glucose as well as under salt, osmotic, and oxidation stress. Colocalization experiments showed that the DsSWEET17-GFP (green fluorescent protein fusion protein was localized to the FM4-64-labeled tonoplasts in Arabidopsis. Compared to the wild type, the transgenic Arabidopsis seedlings overexpressing DsSWEET17 had longer roots, greater fresh weight, and a faster root growth upon exogenous application of fructose. Furthermore, transgenic Arabidopsis seedlings had significantly higher fructose accumulation than was observed for the wild-type seedlings. The analysis of root length revealed that transgenic Arabidopsis had higher tolerance to salt, osmotic, and oxidative stresses. Taken together, our results suggest that DsSWEET17 may be a tonoplast sugar transporter, and its overexpression affects sugar metabolism and confers multiple stress tolerance in Arabidopsis.

  2. DsSWEET17, a Tonoplast-Localized Sugar Transporter from Dianthus spiculifolius, Affects Sugar Metabolism and Confers Multiple Stress Tolerance in Arabidopsis.

    Science.gov (United States)

    Zhou, Aimin; Ma, Hongping; Feng, Shuang; Gong, Shufang; Wang, Jingang

    2018-05-24

    Plant SWEETs (Sugars Will Eventually be Exported Transporters) affect the growth of plants by regulating the transport of sugar from source to sink and its intracellular transport between different organelles. In this study, DsSWEET17 from Dianthus spiculifolius was identified and characterized. Real-time quantitative PCR analysis revealed that the expression of DsSWEET17 was affected by exogenous application of fructose and glucose as well as under salt, osmotic, and oxidation stress. Colocalization experiments showed that the DsSWEET17-GFP (green fluorescent protein) fusion protein was localized to the FM4-64-labeled tonoplasts in Arabidopsis . Compared to the wild type, the transgenic Arabidopsis seedlings overexpressing DsSWEET17 had longer roots, greater fresh weight, and a faster root growth upon exogenous application of fructose. Furthermore, transgenic Arabidopsis seedlings had significantly higher fructose accumulation than was observed for the wild-type seedlings. The analysis of root length revealed that transgenic Arabidopsis had higher tolerance to salt, osmotic, and oxidative stresses. Taken together, our results suggest that DsSWEET17 may be a tonoplast sugar transporter, and its overexpression affects sugar metabolism and confers multiple stress tolerance in Arabidopsis .

  3. Double-filter identification of vascular-expressed genes using Arabidopsis plants with vascular hypertrophy and hypotrophy.

    Science.gov (United States)

    Ckurshumova, Wenzislava; Scarpella, Enrico; Goldstein, Rochelle S; Berleth, Thomas

    2011-08-01

    Genes expressed in vascular tissues have been identified by several strategies, usually with a focus on mature vascular cells. In this study, we explored the possibility of using two opposite types of altered tissue compositions in combination with a double-filter selection to identify genes with a high probability of vascular expression in early organ primordia. Specifically, we generated full-transcriptome microarray profiles of plants with (a) genetically strongly reduced and (b) pharmacologically vastly increased vascular tissues and identified a reproducible cohort of 158 transcripts that fulfilled the dual requirement of being underrepresented in (a) and overrepresented in (b). In order to assess the predictive value of our identification scheme for vascular gene expression, we determined the expression patterns of genes in two unbiased subsamples. First, we assessed the expression patterns of all twenty annotated transcription factor genes from the cohort of 158 genes and found that seventeen of the twenty genes were preferentially expressed in leaf vascular cells. Remarkably, fifteen of these seventeen vascular genes were clearly expressed already very early in leaf vein development. Twelve genes with published leaf expression patterns served as a second subsample to monitor the representation of vascular genes in our cohort. Of those twelve genes, eleven were preferentially expressed in leaf vascular tissues. Based on these results we propose that our compendium of 158 genes represents a sample that is highly enriched for genes expressed in vascular tissues and that our approach is particularly suited to detect genes expressed in vascular cell lineages at early stages of their inception. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  4. Constitutive salicylic acid accumulation in pi4kIII beta 1 beta 2 Arabidopsis plants stunts rosette but not root growth

    Czech Academy of Sciences Publication Activity Database

    Šašek, Vladimír; Janda, Martin; Delage, E.; Puyaubert, J.; Guivarc'h, A.; Maseda, Encarnación López; Dobrev, Petre; Caius, J.; Valentová, O.; Burketová, Lenka; Zachowski, A.; Ruelland, E.

    2014-01-01

    Roč. 203, č. 3 (2014), s. 805-816 ISSN 0028-646X R&D Projects: GA ČR(CZ) GAP501/11/1654 Institutional support: RVO:61389030 Keywords : Arabidopsis * dwarf phenotype * hormone transduction Subject RIV: CE - Biochemistry Impact factor: 7.672, year: 2014

  5. Arabidopsis RecQsim, a plant-specific member of the RecQ helicase family, can suppress the MMS hypersensitivity of the yeast sgs1 mutant

    NARCIS (Netherlands)

    Bagherieh-Najjar, MB; de Vries, OMH; Kroon, JTM; Wright, EL; Elborough, KM; Hille, J; Dijkwel, PP

    The Arabidopsis genome contains seven genes that belong to the RecQ family of ATP-dependent DNA helicases. RecQ members in Saccharomyces cerevisiae (SGS1) and man (WRN, BLM and RecQL4) are involved in DNA recombination, repair and genome stability maintenance, but little is known about the function

  6. Utilization of the higher plants in a study on hereditary effect of low-dose irradiation

    International Nuclear Information System (INIS)

    Yamashita, Jun

    1976-01-01

    Some problems in a study of hereditary effect of low-dose irradiation, which used the higher plants (tradescantia, peas, etc.) as materials, were mentioned. Conditions to be used as materials were mentioned as follows: 1) the materials must have high radio-sensitivity, 2) the natural mutation of the materials must be low, 3) hereditary uniformity and stability of genes in the materials were important, and 4) in case of considering the materials as environmental radiation monitors, the observation period must be long and the duration from exposure to detection of mutation must be short. Tradescantia has most of these conditions, but the greatest fault is that the object of its observation is mutation of somatic cells, and hereditary study is impossible. Therefore, it is necessary to find out other materials in order to solve the problem whether there is a difference in relative frequency of chromosomal abnormalities, which occurrs in germinal cells and is transmitted to posterity, between low and high doses or not. (Serizawa, K.)

  7. Dual biosynthetic pathways to phytosterol via cycloartenol and lanosterol in Arabidopsis.

    Science.gov (United States)

    Ohyama, Kiyoshi; Suzuki, Masashi; Kikuchi, Jun; Saito, Kazuki; Muranaka, Toshiya

    2009-01-20

    The differences between the biosynthesis of sterols in higher plants and yeast/mammals are believed to originate at the cyclization step of oxidosqualene, which is cyclized to cycloartenol in higher plants and lanosterol in yeast/mammals. Recently, lanosterol synthase genes were identified from dicotyledonous plant species including Arabidopsis, suggesting that higher plants possess dual biosynthetic pathways to phytosterols via lanosterol, and through cycloartenol. To identify the biosynthetic pathway to phytosterol via lanosterol, and to reveal the contributions to phytosterol biosynthesis via each cycloartenol and lanosterol, we performed feeding experiments by using [6-(13)C(2)H(3)]mevalonate with Arabidopsis seedlings. Applying (13)C-{(1)H}{(2)H} nuclear magnetic resonance (NMR) techniques, the elucidation of deuterium on C-19 behavior of phytosterol provided evidence that small amounts of phytosterol were biosynthesized via lanosterol. The levels of phytosterol increased on overexpression of LAS1, and phytosterols derived from lanosterol were not observed in a LAS1-knockout plant. This is direct evidence to indicate that the biosynthetic pathway for phytosterol via lanosterol exists in plant cells. We designate the biosynthetic pathway to phytosterols via lanosterol "the lanosterol pathway." LAS1 expression is reported to be induced by the application of jasmonate and is thought to have evolved from an ancestral cycloartenol synthase to a triterpenoid synthase, such as beta-amyrin synthase and lupeol synthase. Considering this background, the lanosterol pathway may contribute to the biosynthesis of not only phytosterols, but also steroids as secondary metabolites.

  8. Effects of chronic exposure of seeds and seeds and seedlings of Arabidopsis Thaliana by low doses of γ-radiation on plant growth and development

    International Nuclear Information System (INIS)

    Litvinov, S.V.

    2013-01-01

    Article presents the results of research on the effect of chronic γ-irradiation in small doses on A. Thaliana seedlings and seeds growth and development. Exposure rate for the seeds was 0,45 mGy/h (total absorbed dose 30 cSv) and 0,18 mGy/h for seedlings (total absorbed dose 3 cSv). Statistically significant differences in the germination capacity, in the time of primary leaf rosette formation, in the hypocotyl length were revealed between irradiated and control seedlings. Plants from irradiated seeds differed by the higher growth rate of stem, they flowered and fruited earlier, but they also characterized on average shorter vegetative cycle in comparison with control plants. In our experiments it is shown significant impact of chronic low doses of γ-irradiation of seeds and seedlings on the ontogeny in A. Thaliana and on the parameters that reflect the growth and development of the irradiated plants

  9. Processes for producing polyhydroxybutyrate and related polyhydroxyalkanoates in the plastids of higher plants

    Science.gov (United States)

    Somerville, C.R.; Nawrath, C.; Poirier, Y.

    1997-03-11

    The present invention relates to a process for producing poly-D-(-)-3-hydroxybutyric acid (PHB) and related polyhydroxyalkanoates (PHA) in the plastids of plants. The production of PHB is accomplished by genetically transforming plants with modified genes from microorganisms. The genes encode the enzymes required to synthesize PHB from acetyl-CoA or related metabolites and are fused with additional plant sequences for targeting the enzymes to the plastid. 37 figs.

  10. Brassinosteriod Insensitive 2 (BIN2) acts as a downstream effector of the Target of Rapamycin (TOR) signaling pathway to regulate photoautotrophic growth in Arabidopsis.

    Science.gov (United States)

    Xiong, Fangjie; Zhang, Rui; Meng, Zhigang; Deng, Kexuan; Que, Yumei; Zhuo, Fengping; Feng, Li; Guo, Sundui; Datla, Raju; Ren, Maozhi

    2017-01-01

    The components of the target of rapamycin (TOR) signaling pathway have been well characterized in heterotrophic organisms from yeast to humans. However, because of rapamycin insensitivity, embryonic lethality in tor null mutants and a lack of reliable ways of detecting TOR protein kinase in higher plants, the key players upstream and downstream of TOR remain largely unknown in plants. Using engineered rapamycin-sensitive Binding Protein 12-2 (BP12-2) plants, the present study showed that combined treatment with rapamycin and active-site TOR inhibitors (asTORis) results in synergistic inhibition of TOR activity and plant growth in Arabidopsis. Based on this system, we revealed that TOR signaling plays a crucial role in modulating the transition from heterotrophic to photoautotrophic growth in Arabidopsis. Ribosomal protein S6 kinase 2 (S6K2) was identified as a direct downstream target of TOR, and the growth of TOR-suppressed plants could be rescued by up-regulating S6K2. Systems, genetic, and biochemical analyses revealed that Brassinosteriod Insensitive 2 (BIN2) acts as a novel downstream effector of S6K2, and the phosphorylation of BIN2 depends on TOR-S6K2 signaling in Arabidopsis. By combining pharmacological with genetic and biochemical approaches, we determined that the TOR-S6K2-BIN2 signaling pathway plays important roles in regulating the photoautotrophic growth of Arabidopsis. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  11. Hygiene evaluation of the air conditions in the Lower Main region by means of higher and lower plants

    Energy Technology Data Exchange (ETDEWEB)

    Steubing, L; Klee, R; Kirschbaum, U

    1974-06-01

    By using the distribution patterns of natural growths of epiphytic lichens, three lichen zones can be distinguished in the Lower Main region of FRG. Each zone corresponds to different degrees of injury to lichens, and each zone is characterized by a particular pollutant load. Damage to plants is functionally correlated with the destruction of chlorophyll. Primary production, dust covering, sulfur content and conductivity of higher plants in two of the lichen zones confirm the data from test stations.

  12. The re-assimilation of ammonia produced by photorespiration and the nitrogen economy of C3 higher plants.

    Science.gov (United States)

    Keys, Alfred J

    2006-02-01

    Photorespiration involves the conversion of glycine to serine with the release of ammonia and CO(2). In C(3) terrestrial higher plants the flux through glycine and serine is so large that it results in the production of ammonia at a rate far exceeding that from reduction of new nitrogen entering the plant. The photorespiratory nitrogen cycle re-assimilates this ammonia using the enzymes glutamine synthetase and glutamine:2-oxoglutarateaminotransferase.

  13. Impact of ubiquitous inhibitors on the GUS gene reporter system: evidence from the model plants Arabidopsis, tobacco and rice and correction methods for quantitative assays of transgenic and endogenous GUS

    Directory of Open Access Journals (Sweden)

    Gerola Paolo D

    2009-12-01

    Full Text Available Abstract Background The β-glucuronidase (GUS gene reporter system is one of the most effective and employed techniques in the study of gene regulation in plant molecular biology. Improving protocols for GUS assays have rendered the original method described by Jefferson amenable to various requirements and conditions, but the serious limitation caused by inhibitors of the enzyme activity in plant tissues has thus far been underestimated. Results We report that inhibitors of GUS activity are ubiquitous in organ tissues of Arabidopsis, tobacco and rice, and significantly bias quantitative assessment of GUS activity in plant transformation experiments. Combined with previous literature reports on non-model species, our findings suggest that inhibitors may be common components of plant cells, with variable affinity towards the E. coli enzyme. The reduced inhibitory capacity towards the plant endogenous GUS discredits the hypothesis of a regulatory role of these compounds in plant cells, and their effect on the bacterial enzyme is better interpreted as a side effect due to their interaction with GUS during the assay. This is likely to have a bearing also on histochemical analyses, leading to inaccurate evaluations of GUS expression. Conclusions In order to achieve reliable results, inhibitor activity should be routinely tested during quantitative GUS assays. Two separate methods to correct the measured activity of the transgenic and endogenous GUS are presented.

  14. An Atlas of Type I MADS Box Gene Expression during Female Gametophyte and Seed Development in Arabidopsis[W].

    NARCIS (Netherlands)

    Bemer, M.; Heijmans, K.; Airoldi, C.A.; Davies, B.; Angenent, G.C.

    2010-01-01

    Members of the plant type I MADS domain subfamily have been reported to be involved in reproductive development in Arabidopsis (Arabidopsis thaliana). However, from the 61 type I genes in the Arabidopsis genome, only PHERES1, AGAMOUS-LIKE80 (AGL80), DIANA, AGL62, and AGL23 have been functionally

  15. Reference: 359 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available 359 http://metadb.riken.jp/db/SciNetS_ria224i/cria224u4ria224u16531491i Cnops Gerda...leaf development in Arabidopsis thaliana. 4 852-66 16531491 2006 Apr The Plant cell Azmi Abdelkrim|Cnops Gerda

  16. Reference: 486 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available time in many plant species through the photoperiod and vernalization pathways, re...cipates in both the photoperiod and vernalization pathways in Arabidopsis thaliana by regulating expression ... of VIN3 in a photoperiod-dependent manner. A PHD finger protein involved in both the vernalization and photoperiod pathways

  17. Reference: 751 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available 751 http://metadb.riken.jp/db/SciNetS_ria224i/cria224u4ria224u18390806i Sitaraman ...unctions during Arabidopsis embryo and floral development. 2 672-81 18390806 2008 Jun Plant physiology Bui Minh|Liu Zhongchi|Sitaraman Jayashree

  18. Reference: 356 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available 006 Mar Plant molecular biology Deng Xingwang|Dong Li|Wang Lei|Xue Yongbiao|Zhang Yansheng|Zhang Yu'e ...ein CEGENDUO negatively regulates auxin-mediated lateral root formation in Arabidopsis. 4 599-615 16525894 2

  19. Proteomics of Arabidopsis seed germination and priming

    NARCIS (Netherlands)

    Gallardo, K.; Job, C.; Groot, S.P.C.; Puype, M.; Demol, H.; Vandekerckhove, J.; Job, D.

    2003-01-01

    To better understand seed germination, a complex developmental process, we developed a proteome analysis of the model plant Arabidopsis for which complete genome sequence is now available. Among about 1,300 total seed proteins resolved in two-dimensional gels, changes in the abundance (up- and

  20. Reference: 689 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available the high affinity of MOT1 allows plants to obtain scarce Mo from soil. An Arabidopsis thaliana high-affinity... molybdate transporter required for efficient uptake of molybdate from soil. 47 18807-12 18003916 2007 Nov P

  1. Reference: 239 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available 239 http://metadb.riken.jp/db/SciNetS_ria224i/cria224u4ria224u16015335i Bundock Paul et al. 2005 Jul. Natur...functions. An Arabidopsis hAT-like transposase is essential for plant development. 7048 282-4 16015335 2005 Jul Nature Bundock Paul|Hooykaas Paul

  2. Reference: 223 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available 223 http://metadb.riken.jp/db/SciNetS_ria224i/cria224u4ria224u15923347i Dohmann Es... cause the cop/det/fus mutant phenotype in Arabidopsis. 7 1967-78 15923347 2005 Jul The Plant cell Dohmann Esther M N|Kuhnle Carola|Schwechheimer Claus

  3. Production characteristics of the "higher plants-soil-like substrate" system as an element of the bioregenerative life support system

    Science.gov (United States)

    Velichko, V. V.; Tikhomirov, A. A.; Ushakova, S. A.; Tikhomirova, N. A.; Shihov, V. N.; Tirranen, L. S.; Gribovskaya, I. A.

    2013-01-01

    The study addresses the possibility of long-duration operation of a higher plant conveyor, using a soil-like substrate (SLS) as the root zone. Chufa (Cyperus esculentus L.), radish (Raphanus sativus L.), and lettuce (Lactuca sativa L.) were used as study material. A chufa community consisting of 4 age groups and radish and lettuce communities consisting of 2 age groups were irrigated with a nutrient solution, which contained mineral elements extracted from the SLS. After each harvest, inedible biomass of the harvested plants and inedible biomasses of wheat and saltwort were added to the SLS. The amounts of the inedible biomasses of wheat and saltwort to be added to the SLS were determined based on the nitrogen content of the edible mass of harvested plants. CO2 concentration in the growth chamber was maintained within the range of 1100-1700 ppm. The results of the study show that higher plants can be grown quite successfully using the proposed process of plant waste utilization in the SLS. The addition of chufa inedible biomass to the SLS resulted in species-specific inhibition of growth of both cultivated crops and microorganisms in the "higher plants - SLS" system. There were certain differences between the amounts of some mineral elements removed from the SLS with the harvested edible biomass and those added to it with the inedible biomasses of wheat and saltwort.

  4. CEZ utility's coal-fired power plants: towards a higher environmental friendliness

    International Nuclear Information System (INIS)

    Kindl, V.; Spilkova, T.; Vanousek, I.; Stehlik, J.

    1996-01-01

    Environmental efforts of the major Czech utility, CEZ a.s., are aimed at reducing air pollution arising from electricity and heat generating facilities. There are 3 main kinds of activity in this respect: phasing out of coal fired power plants; technological provisions to reduce emissions of particulate matter, sulfur dioxide, and nitrogen oxides from those coal fired units that are to remain in operation after 1998; and completion of the Temelin nuclear power plant. In 1995, emissions of particulate matter, sulfur dioxide, nitrogen oxides, and carbon monoxide from CEZ's coal fired power plants were 19%, 79%, 59%, and 60%, respectively, with respect to the situation in 1992. The break-down of electricity generation by CEZ facilities (in GWh) was as follows in 1995: hydroelectric power plants 1673, nuclear power plants 12230, coal fired power plants without desulfurization equipment 30181, and coal fired power plants with desulfurization equipment 2277. Provisions implemented to improve the environmental friendliness of the individual CEZ's coal fired power plants are described in detail. (P.A.). 5 tabs., 1 fig

  5. Arsenic triggers the nitric oxide (NO) and S-nitrosoglutathione (GSNO) metabolism in Arabidopsis

    International Nuclear Information System (INIS)

    Leterrier, Marina; Airaki, Morad; Palma, José M.; Chaki, Mounira; Barroso, Juan B.; Corpas, Francisco J.

    2012-01-01

    Environmental contamination by arsenic constitutes a problem in many countries, and its accumulation in food crops may pose health complications for humans. Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are involved at various levels in the mechanism of responding to environmental stress in higher plants. Using Arabidopsis seedlings exposed to different arsenate concentrations, physiological and biochemical parameters were analyzed to determine the status of ROS and RNS metabolisms. Arsenate provoked a significant reduction in growth parameters and an increase in lipid oxidation. These changes were accompanied by an alteration in antioxidative enzymes and the nitric oxide (NO) metabolism, with a significant increase in NO content, S-nitrosoglutathione reductase (GSNOR) activity and protein tyrosine nitration as well as a concomitant reduction in glutathione and S-nitrosoglutathione (GSNO) content. Our results indicate that 500 μM arsenate (AsV) causes nitro-oxidative stress in Arabidopsis, being the glutathione reductase and the GSNOR activities clearly affected. - Highlights: ► In Arabidopsis, arsenate provokes damages in the membrane integrity of root cells. ► As induces an oxidative stress according to an increase in lipid oxidation. ► NO content and protein tyrosine nitration increases under arsenate stress. ► Arsenate provokes a reduction of GSH, GSSG and GSNO content. ► Arsenate induces a nitro-oxidative stress in Arabidopsis. - Arsenic stress affects nitric oxide (NO) and glutathione (GSH) metabolism which provokes a nitro-oxidative stress.

  6. AGROBEST: an efficient Agrobacterium-mediated transient expression method for versatile gene function analyses in Arabidopsis seedlings

    Science.gov (United States)

    2014-01-01

    Background Transient gene expression via Agrobacterium-mediated DNA transfer offers a simple and fast method to analyze transgene functions. Although Arabidopsis is the most-studied model plant with powerful genetic and genomic resources, achieving highly efficient and consistent transient expression for gene function analysis in Arabidopsis remains challenging. Results We developed a highly efficient and robust Agrobacterium-mediated transient expression system, named AGROBEST (Agrobacterium-mediated enhanced seedling transformation), which achieves versatile analysis of diverse gene functions in intact Arabidopsis seedlings. Using β-glucuronidase (GUS) as a reporter for Agrobacterium-mediated transformation assay, we show that the use of a specific disarmed Agrobacterium strain with vir gene pre-induction resulted in homogenous GUS staining in cotyledons of young Arabidopsis seedlings. Optimization with AB salts in plant culture medium buffered with acidic pH 5.5 during Agrobacterium infection greatly enhanced the transient expression levels, which were significantly higher than with two existing methods. Importantly, the optimized method conferred 100% infected seedlings with highly increased transient expression in shoots and also transformation events in roots of ~70% infected seedlings in both the immune receptor mutant efr-1 and wild-type Col-0 seedlings. Finally, we demonstrated the versatile applicability of the method for examining transcription factor action and circadian reporter-gene regulation as well as protein subcellular localization and protein–protein interactions in physiological contexts. Conclusions AGROBEST is a simple, fast, reliable, and robust transient expression system enabling high transient expression and transformation efficiency in Arabidopsis seedlings. Demonstration of the proof-of-concept experiments elevates the transient expression technology to the level of functional studies in Arabidopsis seedlings in addition to previous

  7. Acquisition and Homeostasis of Iron in Higher Plants and Their Probable Role in Abiotic Stress Tolerance

    Directory of Open Access Journals (Sweden)

    Durgesh K. Tripathi

    2018-02-01

    Full Text Available Iron (Fe is a micronutrient that plays an important role in agriculture worldwide because plants require a small amount of iron for its growth and development. All major functions in a plant's life from chlorophyll biosynthesis to energy transfer are performed by Fe (Brumbarova et al., 2008; Gill and Tuteja, 2011. Iron also acts as a major constituent of many plant proteins and enzymes. The acquisition of Fe in plants occurs through two strategies, i.e., strategy I and strategy II (Marschner and Römheld, 1994. Under various stress conditions, Nramp and the YSL gene families help in translocation of Fe, which further acts as a mineral regulatory element and defends plants against stresses. Iron plays an irreplaceable role in alleviating stress imposed by salinity, drought, and heavy metal stress. This is because it activates plant enzymatic antioxidants like catalase (CAT, peroxidase, and an isoform of superoxide dismutase (SOD that act as a scavenger of reactive oxygen species (ROS (Hellin et al., 1995. In addition to this, their deficiency as well as their excess amount can disturb the homeostasis of a plant's cell and result in declining of photosynthetic rate, respiration, and increased accumulation of Na+ and Ca− ions which culminate in an excessive formation of ROS. The short-range order hydrated Fe oxides and organic functional groups show affinities for metal ions. Iron plaque biofilm matrices could sequester a large amount of metals at the soil–root interface. Hence, it has attracted the attention of plant physiologists and agricultural scientists who are discovering more exciting and hidden applications of Fe and its potential in the development of bio-factories. This review looks into the recent progress made in putting forward the role of Fe in plant growth, development, and acclimation under major abiotic stresses, i.e., salinity, drought, and heavy metals.

  8. Differentiating moss from higher plants is critical in studying the carbon cycle of the boreal biome

    DEFF Research Database (Denmark)

    Yuan, Wenping; Liu, Shuguang; Dong, Wenjie

    2014-01-01

    The satellite-derived normalized difference vegetation index (NDVI), which is used for estimating gross primary production (GPP), often includes contributions from both mosses and vascular plants in boreal ecosystems. For the same NDVI, moss can generate only about one-third of the GPP...... that vascular plants can because of its much lower photosynthetic capacity. Here, based on eddy covariance measurements, we show that the difference in photosynthetic capacity between these two plant functional types has never been explicitly included when estimating regional GPP in the boreal region, resulting...

  9. Cross genome comparisons of serine proteases in Arabidopsis and rice

    Directory of Open Access Journals (Sweden)

    Sowdhamini R

    2006-08-01

    Full Text Available Abstract Background Serine proteases are one of the largest groups of proteolytic enzymes found across all kingdoms of life and are associated with several essential physiological pathways. The availability of Arabidopsis thaliana and rice (Oryza sativa genome sequences has permitted the identification and comparison of the repertoire of serine protease-like proteins in the two plant species. Results Despite the differences in genome sizes between Arabidopsis and rice, we identified a very similar number of serine protease-like proteins in the two plant species (206 and 222, respectively. Nearly 40% of the above sequences were identified as potential orthologues. Atypical members could be identified in the plant genomes for Deg, Clp, Lon, rhomboid proteases and species-specific members were observed for the highly populated subtilisin and serine carboxypeptidase families suggesting multiple lateral gene transfers. DegP proteases, prolyl oligopeptidases, Clp proteases and rhomboids share a significantly higher percentage orthology between the two genomes indicating substantial evolutionary divergence was set prior to speciation. Single domain architectures and paralogues for several putative subtilisins, serine carboxypeptidases and rhomboids suggest they may have been recruited for additional roles in secondary metabolism with spatial and temporal regulation. The analysis reveals some domain architectures unique to either or both of the plant species and some inactive proteases, like in rhomboids and Clp proteases, which could be involved in chaperone function. Conclusion The systematic analysis of the serine protease-like proteins in the two plant species has provided some insight into the possible functional associations of previously uncharacterised serine protease-like proteins. Further investigation of these aspects may prove beneficial in our understanding of similar processes in commercially significant crop plant species.

  10. Genome structures and halophyte-specific gene expression of the extremophile thellungiella parvula in comparison with Thellungiella salsuginea (Thellungiella halophila) and arabidopsis

    KAUST Repository

    Oh, Dongha

    2010-09-10

    The genome of Thellungiella parvula, a halophytic relative of Arabidopsis (Arabidopsis thaliana), is being assembled using Roche-454 sequencing. Analyses of a 10-Mb scaffold revealed synteny with Arabidopsis, with recombination and inversion and an uneven distribution of repeat sequences. T. parvula genome structure and DNA sequences were compared with orthologous regions from Arabidopsis and publicly available bacterial artificial chromosome sequences from Thellungiella salsuginea (previously Thellungiella halophila). The three-way comparison of sequences, from one abiotic stress-sensitive species and two tolerant species, revealed extensive sequence conservation and microcolinearity, but grouping Thellungiella species separately from Arabidopsis. However, the T. parvula segments are distinguished from their T. salsuginea counterparts by a pronounced paucity of repeat sequences, resulting in a 30% shorter DNA segment with essentially the same gene content in T. parvula. Among the genes is SALT OVERLY SENSITIVE1 (SOS1), a sodium/proton antiporter, which represents an essential component of plant salinity stress tolerance. Although the SOS1 coding region is highly conserved among all three species, the promoter regions show conservation only between the two Thellungiella species. Comparative transcript analyses revealed higher levels of basal as well as salt-induced SOS1 expression in both Thellungiella species as compared with Arabidopsis. The Thellungiella species and other halophytes share conserved pyrimidine-rich 5\\' untranslated region proximal regions of SOS1 that are missing in Arabidopsis. Completion of the genome structure of T. parvula is expected to highlight distinctive genetic elements underlying the extremophile lifestyle of this species. © American Society of Plant Biologists.

  11. Loss and recovery of Arabidopsis-type telomere repeat sequences 5'-(TTTAGGG)(n)-3' in the evolution of a major radiation of flowering plants.

    OpenAIRE

    Adams, S. P.; Hartman, T. P.; Lim, K. Y.; Chase, M. W.; Bennett, M. D.; Leitch, I. J.; Leitch, A. R.

    2001-01-01

    Fluorescent in situ hybridization and Southern blotting were used for showing the predominant absence of the Arabidopsis-type telomere repeat sequence (TRS) 5'-(TTTAGGG)(n)-3' (the 'typical' telomere) in a monocot clade which comprises up to 6300 species within Asparagales. Initially, two apparently disparate genera that lacked the typical telomere were identified. Here, we used the new angiosperm phylogenetic classification for predicting in which other related families such telomeres might ...

  12. Comparative Phenotypical and Molecular Analyses of Arabidopsis Grown under Fluorescent and LED Light

    Directory of Open Access Journals (Sweden)

    Franka Seiler

    2017-06-01

    Full Text Available Comparative analyses of phenotypic and molecular traits of Arabidopsis thaliana grown under standardised conditions is still a challenge using climatic devices supplied with common light sources. These are in most cases fluorescent lights, which have several disadvantages such as heat production at higher light intensities, an invariable spectral output, and relatively rapid “ageing”. This results in non-desired variations of growth conditions and lowers the comparability of data acquired over extended time periods. In this study, we investigated the growth behaviour of Arabidopsis Col0 under different light conditions, applying fluorescent compared to LED lamps, and we conducted physiological as well as gene expression analyses. By changing the spectral composition and/or light intensity of LEDs we can clearly influence the growth behaviour of Arabidopsis and thereby study phenotypic attributes under very specific light conditions that are stable and reproducible, which is not necessarily given for fluorescent lamps. By using LED lights, we can also roughly mimic the sun light emission spectrum, enabling us to study plant growth in a more natural-like light set-up. We observed distinct growth behaviour under the different light regimes which was reflected by physiological properties of the plants. In conclusion, LEDs provide variable emission spectra for studying plant growth under defined, stable light conditions.

  13. Zinc oxide and silver nanoparticles influence the antioxidative status in a higher aquatic plant, Spirodela punctata

    CSIR Research Space (South Africa)

    Thwala, Melusi

    2012-09-01

    Full Text Available during the 14-d exposure. The biochemical anti-oxidative status of the plant specimens were investigated using quantitative analysis of total antioxidant capacity, peroxidase and activity of catalase and superoxide dismutase. The anti-oxidative defence...

  14. Integration of pharmaceuticals with higher plants as a model of phytoremediation

    OpenAIRE

    Pomeislová, Alice

    2015-01-01

    The presence of pharmaceuticals in wastewater, which are not eliminated in sewage treatment plant process and thus get easily into rivers and aquatic environment in general, constitutes a severe problem to the whole society. The research into the removal of pharmaceuticals from the environment began about twenty years ago. Phytoremediation represents one of the most promising wastewater treatment methods. It is based on the ability of plants to remove xenobiotics from their environment and se...

  15. Interactions of metal-based engineered nanoparticles with aquatic higher plants: A review of the state of current knowledge.

    Science.gov (United States)

    Thwala, Melusi; Klaine, Stephen J; Musee, Ndeke

    2016-07-01

    The rising potential for the release of engineered nanoparticles (ENPs) into aquatic environments requires evaluation of risks to protect ecological health. The present review examines knowledge pertaining to the interactions of metal-based ENPs with aquatic higher plants, identifies information gaps, and raises considerations for future research to advance knowledge on the subject. The discussion focuses on ENPs' bioaccessibility; uptake, adsorption, translocation, and bioaccumulation; and toxicity effects on aquatic higher plants. An information deficit surrounds the uptake of ENPs and associated dynamics, because the influence of ENP characteristics and water quality conditions has not been well documented. Dissolution appears to be a key mechanism driving bioaccumulation of ENPs, whereas nanoparticulates often adsorb to plant surfaces with minimal internalization. However, few reports document the internalization of ENPs by plants; thus, the role of nanoparticulates' internalization in bioaccumulation and toxicity remains unclear, requiring further investigation. The toxicities of metal-based ENPs mainly have been associated with dissolution as a predominant mechanism, although nano toxicity has also been reported. To advance knowledge in this domain, future investigations need to integrate the influence of ENP characteristics and water physicochemical parameters, as their interplay determines ENP bioaccessibility and influences their risk to health of aquatic higher plants. Furthermore, harmonization of test protocols is recommended for fast tracking the generation of comparable data. Environ Toxicol Chem 2016;35:1677-1694. © 2016 SETAC. © 2016 SETAC.

  16. Enhanced Thermostability of Arabidopsis Rubisco Activase Improves Photosynthesis and Growth Rates under Moderate Heat Stress[OA

    Science.gov (United States)

    Kurek, Itzhak; Chang, Thom Kai; Bertain, Sean M.; Madrigal, Alfredo; Liu, Lu; Lassner, Michael W.; Zhu, Genhai

    2007-01-01

    Plant photosynthesis declines when the temperature exceeds its optimum range. Recent evidence indicates that the reduction in photosynthesis is linked to ribulose-1,5-bis-phosphate carboxylase/oxygenase (Rubisco) deactivation due to the inhibition of Rubisco activase (RCA) under moderately elevated temperatures. To test the hypothesis that thermostable RCA can improve photosynthesis under elevated temperatures, we used gene shuffling technology to generate several Arabidopsis thaliana RCA1 (short isoform) variants exhibiting improved thermostability. Wild-type RCA1 and selected thermostable RCA1 variants were introduced into an Arabidopsis RCA deletion (Δrca) line. In a long-term growth test at either constant 26°C or daily 4-h 30°C exposure, the transgenic lines with the thermostable RCA1 variants exhibited higher photosynthetic rates, improved development patterns, higher biomass, and increased seed yields compared with the lines expressing wild-type RCA1 and a slight improvement compared with untransformed Arabidopsis plants. These results provide clear evidence that RCA is a major limiting factor in plant photosynthesis under moderately elevated temperatures and a potential target for genetic manipulation to improve crop plants productivity under heat stress conditions. PMID:17933901

  17. Reference: 126 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available on of Hsp93 during protein import into chloroplasts, we isolated knockout mutant ...red to the wild type. Plastid protein composition, however, seems to be largely unaffected in atHsp93-V knock...out plants. Chloroplasts isolated from the atHsp93-V knockout mutant line are still able to import a variet...biogenesis of Arabidopsis chloroplasts. In contrast, knockout mutant plants for atHsp93-III, the second Arab

  18. Production characteristics of lettuce Lactuca sativa L. in the frame of the first crop tests in the Higher Plant Chamber integrated into the MELiSSA Pilot Plant

    Science.gov (United States)

    Tikhomirova, Natalia; Lawson, Jamie; Stasiak, Michael; Dixon, Mike; Paille, Christel; Peiro, Enrique; Fossen, Arnaud; Godia, Francesc

    Micro-Ecological Life Support System Alternative (MELiSSA) is an artificial closed ecosystem that is considered a tool for the development of a bioregenerative life support system for manned space missions. One of the five compartments of MELiSSA loop -Higher Plant Chamber was recently integrated into the MELiSSA Pilot Plant facility at Universitat Aut`noma deo Barcelona. The main contributions expected by integration of this photosynthetic compartment are oxygen, water, vegetable food production and CO2 consumption. Production characteristics of Lactuca sativa L., as a MELiSSA candidate crop, were investigated in this work in the first crop experiments in the MELiSSA Pilot Plant facility. The plants were grown in batch culture and totaled 100 plants with a growing area 5 m long and 1 m wide in a sealed controlled environment. Several replicates of the experiments were carried out with varying duration. It was shown that after 46 days of lettuce cultivation dry edible biomass averaged 27, 2 g per plant. However accumulation of oxygen in the chamber, which required purging of the chamber, and decrease in the food value of the plants was observed. Reducing the duration of the tests allowed uninterrupted test without opening the system and also allowed estimation of the crop's carbon balance. Results of productivity, tissue composition, nutrient uptake and canopy photosynthesis of lettuce regardless of test duration are discussed in the paper.

  19. Two bee-pollinated plant species show higher seed production when grown in gardens compared to arable farmland.

    Directory of Open Access Journals (Sweden)

    John Cussans

    2010-07-01

    Full Text Available Insect pollinator abundance, in particular that of bees, has been shown to be high where there is a super-abundance of floral resources; for example in association with mass-flowering crops and also in gardens where flowering plants are often densely planted. Since land management affects pollinator numbers, it is also likely to affect the resultant pollination of plants growing in these habitats. We hypothesised that the seed or fruit set of two plant species, typically pollinated by bumblebees and/or honeybees might respond in one of two ways: 1 pollination success could be reduced when growing in a floriferous environment, via competition for pollinators, or 2 pollination success could be enhanced because of increased pollinator abundance in the vicinity.We compared the pollination success of experimental plants of Glechoma hederacea L. and Lotus corniculatus L. growing in gardens and arable farmland. On the farms, the plants were placed either next to a mass-flowering crop (oilseed rape, Brassica napus L. or field beans, Vicia faba L. or next to a cereal crop (wheat, Triticum spp.. Seed set of G. hederacea and fruit set of L. corniculatus were significantly higher in gardens compared to arable farmland. There was no significant difference in pollination success of G. hederacea when grown next to different crops, but for L. corniculatus, fruit set was higher in the plants growing next to oilseed rape when the crop was in flower.The results show that pollination services can limit fruit set of wild plants in arable farmland, but there is some evidence that the presence of a flowering crop can facilitate their pollination (depending on species and season. We have also demonstrated that gardens are not only beneficial to pollinators, but also to the process of pollination.

  20. MOLECULAR-GENETIC BASIS OF HIGHER PLANTS TOLERANCE TO, AND ACCUMULATION OF, CADMIUM

    Directory of Open Access Journals (Sweden)

    Olga A Kulaeva

    2010-09-01

    Full Text Available Cadmium (Cd is one of the most wide-ranged and dangerous pollutants for all living organisms, including plants. At present time the intensive studies of mechanisms of Cd accumulation in plant tissues and plant tolerance to its toxic influence are performed. Data about variation of Cd tolerance and accumulation traits in natural populations of hyperaccumulators species as well as important crops were obtained. A series of mutants with changed sensitivity to Cd was obtained. In recent decade several classes of proteins involving in cell responses to Cd ions were revealed. An important role of microRNA in plant adaptation to Cd was recently demonstrated. Studies of molecular-genetic mechanisms of Cd accumulation and plant tolerance to it are theoretical basis for development of phytoremediation technologies of soil contaminated with heavy metals and breeding of crop varieties with decreased Cd accumulation.

  1. The effect of UVB on flavonoid biosynthesis in wild type and mutant petunia and arabidopsis

    International Nuclear Information System (INIS)

    Ryan, K.G.; Swinny, E.E.; Markham, K.R.; Winefield, C.

    2000-01-01

    Full text: Flavonoids may protect plants against damage by UVB radiation. Flavonoid composition and mRNA expression were determined following growth of plants under natural light, and under natural light with low UVB and with enhanced UVB. In wild-type Arabidopsis and Petunia, UVB induced an increase in total levels of flavonols and this was due to an up-regulation of, several genes coding for key enzymes in the phenylpropanoid pathway. In addition, UVB induced a higher rate of production of the di-hydroxylated si flavonol, quercetin glycoside than of the mono-hydroxylated equivalent, of kaempferol glycoside. Thus the ratio of quercetin to kaempferol increased with UVB treatment in wild type plants, and this suggests that the flavonoid r 3'hydroxylase (F3'H) enzyme, which converts dihydrokaempferol to dihydroquercetin, may play a key role in plant protection from UVB. Mutant plants of both species lacking this F3'H gene were grown under similar UV conditions. Leaves of the mutant Arabidopsis plant (tt7) did not contain quercetin, even under the enhanced UVB treatment. Under the low UVB treatment the total amount of flavonol was similar to the wild-type (Ler), but with increasing UVB, total flavonol (i.e. kaempferol) levels were significantly higher than in similarly treated wild type plants. In the Petunia F3'H mutant, low levels of quercetin were found even in the low UVB treatment, which indicates this variety may be producing some quercetin via an alternative pathway. Under UVB radiation, total flavonoids increased to levels significantly higher than in similarly treated wild type plants, and most of this material was kaempferol. These observations suggest that quercetin is the preferred protective flavonol in wild type plants, due perhaps to enhanced antioxidant or free radical scavenging activity. In mutant plants lacking the F3'H enzyme, the response is to produce a larger amount of a less effective photoprotectant

  2. Differentiating moss from higher plants is critical in studying the carbon cycle of the boreal biome.

    Science.gov (United States)

    Yuan, Wenping; Liu, Shuguang; Dong, Wenjie; Liang, Shunlin; Zhao, Shuqing; Chen, Jingming; Xu, Wenfang; Li, Xianglan; Barr, Alan; Andrew Black, T; Yan, Wende; Goulden, Mike L; Kulmala, Liisa; Lindroth, Anders; Margolis, Hank A; Matsuura, Yojiro; Moors, Eddy; van der Molen, Michiel; Ohta, Takeshi; Pilegaard, Kim; Varlagin, Andrej; Vesala, Timo

    2014-06-26

    The satellite-derived normalized difference vegetation index (NDVI), which is used for estimating gross primary production (GPP), often includes contributions from both mosses and vascular plants in boreal ecosystems. For the same NDVI, moss can generate only about one-third of the GPP that vascular plants can because of its much lower photosynthetic capacity. Here, based on eddy covariance measurements, we show that the difference in photosynthetic capacity between these two plant functional types has never been explicitly included when estimating regional GPP in the boreal region, resulting in a substantial overestimation. The magnitude of this overestimation could have important implications regarding a change from a current carbon sink to a carbon source in the boreal region. Moss abundance, associated with ecosystem disturbances, needs to be mapped and incorporated into GPP estimates in order to adequately assess the role of the boreal region in the global carbon cycle.

  3. Differentiating moss from higher plants is critical in studying the carbon cycle of the boreal biome

    Science.gov (United States)

    Yuan, Wenping; Liu, Shuguang; Dong, Wenjie; Liang, Shunlin; Zhao, Shuqing; Chen, Jingming; Xu, Wenfang; Li, Xianglan; Barr, Alan; Black, T. Andrew; Yan, Wende; Goulden, Michael; Kulmala, Liisa; Lindroth, Anders; Margolis, Hank A.; Matsuura, Yojiro; Moors, Eddy; van der Molen, Michiel; Ohta, Takeshi; Pilegaard, Kim; Varlagin, Andrej; Vesala, Timo

    2014-01-01

    The satellite-derived normalized difference vegetation index (NDVI), which is used for estimating gross primary production (GPP), often includes contributions from both mosses and vascular plants in boreal ecosystems. For the same NDVI, moss can generate only about one-third of the GPP that vascular plants can because of its much lower photosynthetic capacity. Here, based on eddy covariance measurements, we show that the difference in photosynthetic capacity between these two plant functional types has never been explicitly included when estimating regional GPP in the boreal region, resulting in a substantial overestimation. The magnitude of this overestimation could have important implications regarding a change from a current carbon sink to a carbon source in the boreal region. Moss abundance, associated with ecosystem disturbances, needs to be mapped and incorporated into GPP estimates in order to adequately assess the role of the boreal region in the global carbon cycle.

  4. Can genetically based clines in plant defence explain greater herbivory at higher latitudes?

    Science.gov (United States)

    Anstett, Daniel N; Ahern, Jeffrey R; Glinos, Julia; Nawar, Nabanita; Salminen, Juha-Pekka; Johnson, Marc T J

    2015-12-01

    Greater plant defence is predicted to evolve at lower latitudes in response to increased herbivore pressure. However, recent studies question the generality of this pattern. In this study, we tested for genetically based latitudinal clines in resistance to herbivores and underlying defence traits of Oenothera biennis. We grew plants from 137 populations from across the entire native range of O. biennis. Populations from lower latitudes showed greater resistance to multiple specialist and generalist herbivores. These patterns were associated with an increase in total phenolics at lower latitudes. A significant proportion of the phenolics were driven by the concentrations of two major ellagitannins, which exhibited opposing latitudinal clines. Our analyses suggest that these findings are unlikely to be explained by local adaptation of herbivore populations or genetic variation in phenology. Rather greater herbivory at high latitudes can be explained by latitudinal clines in the evolution of plant defences. © 2015 John Wiley & Sons Ltd/CNRS.

  5. Engineering plastid fatty acid biosynthesis to improve food quality and biofuel production in higher plants.

    Science.gov (United States)

    Rogalski, Marcelo; Carrer, Helaine

    2011-06-01

    The ability to manipulate plant fatty acid biosynthesis by using new biotechnological approaches has allowed the production of transgenic plants with unusual fatty acid profile and increased oil content. This review focuses on the production of very long chain polyunsaturated fatty acids (VLCPUFAs) and the increase in oil content in plants using molecular biology tools. Evidences suggest that regular consumption of food rich in VLCPUFAs has multiple positive health benefits. Alternative sources of these nutritional fatty acids are found in cold-water fishes. However, fish stocks are in severe decline because of decades of overfishing, and also fish oils can be contaminated by the accumulation of toxic compounds. Recently, there is also an increase in oilseed use for the production of biofuels. This tendency is partly associated with the rapidly rising costs of petroleum, increased concern about the environmental impact of fossil oil and the attractive need to develop renewable sources of fuel. In contrast to this scenario, oil derived from crop plants is normally contaminant free and less environmentally aggressive. Genetic engineering of the plastid genome (plastome) offers a number of attractive advantages, including high-level foreign protein expression, marker-gene excision and transgene containment because of maternal inheritance of plastid genome in most crops. Here, we describe the possibility to improve fatty acid biosynthesis in plastids, production of new fatty acids and increase their content in plants by genetic engineering of plastid fatty acid biosynthesis via plastid transformation. © 2011 The Authors. Plant Biotechnology Journal © 2011 Society for Experimental Biology, Association of Applied Biologists and Blackwell Publishing Ltd.

  6. Congruence and diversity of butterfly-host plant associations at higher taxonomic levels.

    Directory of Open Access Journals (Sweden)

    José R Ferrer-Paris

    Full Text Available We aggregated data on butterfly-host plant associations from existing sources in order to address the following questions: (1 is there a general correlation between host diversity and butterfly species richness?, (2 has the evolution of host plant use followed consistent patterns across butterfly lineages?, (3 what is the common ancestral host plant for all butterfly lineages? The compilation included 44,148 records from 5,152 butterfly species (28.6% of worldwide species of Papilionoidea and 1,193 genera (66.3%. The overwhelming majority of butterflies use angiosperms as host plants. Fabales is used by most species (1,007 spp. from all seven butterfly families and most subfamilies, Poales is the second most frequently used order, but is mostly restricted to two species-rich subfamilies: Hesperiinae (56.5% of all Hesperiidae, and Satyrinae (42.6% of all Nymphalidae. We found a significant and strong correlation between host plant diversity and butterfly species richness. A global test for congruence (Parafit test was sensitive to uncertainty in the butterfly cladogram, and suggests a mixed system with congruent associations between Papilionidae and magnoliids, Hesperiidae and monocots, and the remaining subfamilies with the eudicots (fabids and malvids, but also numerous random associations. The congruent associations are also recovered as the most probable ancestral states in each node using maximum likelihood methods. The shift from basal groups to eudicots appears to be more likely than the other way around, with the only exception being a Satyrine-clade within the Nymphalidae that feed on monocots. Our analysis contributes to the visualization of the complex pattern of interactions at superfamily level and provides a context to discuss the timing of changes in host plant utilization that might have promoted diversification in some butterfly lineages.

  7. Congruence and diversity of butterfly-host plant associations at higher taxonomic levels.

    Science.gov (United States)

    Ferrer-Paris, José R; Sánchez-Mercado, Ada; Viloria, Ángel L; Donaldson, John

    2013-01-01

    We aggregated data on butterfly-host plant associations from existing sources in order to address the following questions: (1) is there a general correlation between host diversity and butterfly species richness?, (2) has the evolution of host plant use followed consistent patterns across butterfly lineages?, (3) what is the common ancestral host plant for all butterfly lineages? The compilation included 44,148 records from 5,152 butterfly species (28.6% of worldwide species of Papilionoidea) and 1,193 genera (66.3%). The overwhelming majority of butterflies use angiosperms as host plants. Fabales is used by most species (1,007 spp.) from all seven butterfly families and most subfamilies, Poales is the second most frequently used order, but is mostly restricted to two species-rich subfamilies: Hesperiinae (56.5% of all Hesperiidae), and Satyrinae (42.6% of all Nymphalidae). We found a significant and strong correlation between host plant diversity and butterfly species richness. A global test for congruence (Parafit test) was sensitive to uncertainty in the butterfly cladogram, and suggests a mixed system with congruent associations between Papilionidae and magnoliids, Hesperiidae and monocots, and the remaining subfamilies with the eudicots (fabids and malvids), but also numerous random associations. The congruent associations are also recovered as the most probable ancestral states in each node using maximum likelihood methods. The shift from basal groups to eudicots appears to be more likely than the other way around, with the only exception being a Satyrine-clade within the Nymphalidae that feed on monocots. Our analysis contributes to the visualization of the complex pattern of interactions at superfamily level and provides a context to discuss the timing of changes in host plant utilization that might have promoted diversification in some butterfly lineages.

  8. Abilities of some higher plants to hydrolyze the acetates of phenols and aromatic-aliphatic alcohols

    Directory of Open Access Journals (Sweden)

    Agnieszka Mironowicz

    2014-01-01

    Full Text Available In the biotransformations carried out under the same conditions, the whole intact plants of Spirodela punctata, Nephrolepis exaltata, Cyrtomium falcatum, Nephrolepis cordifolia and the suspension cultures of Helianthus tuberosus, Daucus carota and Petunia hybrida hydrolyze (partially or totally the ester bonds of the acetates of phenols and aromatic-aliphatic alcohols and also the menthyl acetate. Nevertheless, the methyl esters of aromatic acids, structurally similar to the former substrates, do not undergo hydrolysis. At the same time, the viability of first four plants was observed for different levels of acetate concentration. The method of continuous preparative hydrolysis of the same acetates was worked out in Cyrtomium falcatum culture.

  9. Utilization of respiratory energy in higher plants : requirements for 'maintenance' and transport processes

    NARCIS (Netherlands)

    Bouma, T.J.

    1995-01-01

    Quantitative knowledge of both photosynthesis and respiration is required to understand plant growth and resulting crop yield. However, especially the nature of the energy demanding processes that are dependent on dark respiration in full-grown tissues is largely unknown. The main objective

  10. Zinc oxide and silver nanoparticles influence the antioxidative status in a higher aquatic plant, Spirodela punctata

    CSIR Research Space (South Africa)

    Thwala, Melusi

    2012-09-01

    Full Text Available The authors present evidence of free radical activity and resultant anti-oxidative defence in Spirodela plants after exposure to 0.01-1000 mg/L of ZnO and Ag nanoparticles (NPs) over 96-h and 14-d. The quantification of reactive nitrogen...

  11. Higher operational safety of nuclear power plants by evaluating the behaviour of operating personnel

    International Nuclear Information System (INIS)

    Mertins, M.; Glasner, P.

    1990-01-01

    In the GDR power reactors have been operated since 1966. Since that time operational experiences of 73 cumulative reactor years have been collected. The behaviour of operating personnel is an essential factor to guarantee the safety of operation of the nuclear power plant. Therefore a continuous analysis of the behaviour of operating personnel has been introduced at the GDR nuclear power plants. In the paper the overall system of the selection, preparation and control of the behaviour of nuclear power plant operating personnel is presented. The methods concerned are based on recording all errors of operating personnel and on analyzing them in order to find out the reasons. The aim of the analysis of reasons is to reduce the number of errors. By a feedback of experiences the nuclear safety of the nuclear power plant can be increased. All data necessary for the evaluation of errors are recorded and evaluated by a computer program. This method is explained thoroughly in the paper. Selected results of error analysis are presented. It is explained how the activities of the personnel are made safer by means of this analysis. Comparisons with other methods are made. (author). 3 refs, 4 figs

  12. Predicting molybdenum toxicity to higher plants: Estimation of toxicity threshold values

    Energy Technology Data Exchange (ETDEWEB)

    McGrath, S.P., E-mail: steve.mcgrath@bbsrc.ac.u [Soil Science Department, Centre for Soils and Ecosystems Function, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ (United Kingdom); Mico, C.; Zhao, F.J.; Stroud, J.L. [Soil Science Department, Centre for Soils and Ecosystems Function, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ (United Kingdom); Zhang, H.; Fozard, S. [Division of Environmental Science, Lancaster University, Lancaster LA1 4YQ (United Kingdom)

    2010-10-15

    Four plant species (oilseed rape, Brassica napus L.; red clover, Trifolium pratense L.; ryegrass, Lolium perenne L.; and tomato, Lycopersicon esculentum L.) were tested on ten soils varying widely in soil properties to assess molybdenum (Mo) toxicity. A larger range (66-fold-609-fold) of added Mo concentrations resulting in 50% inhibition of yield (ED{sub 50}) was found among soils than among plant species (2-fold-38-fold), which illustrated that the soils differed widely in the expression of Mo toxicity. Toxicity thresholds based on soil solution Mo narrowed the variation among soils compared to thresholds based on added Mo concentrations. We conclude that plant bioavailability of Mo in soil depends on Mo solubility, but this alone did not decrease the variability in observed toxicity enough to be used in risk assessment and that other soil properties influencing Mo toxicity to plants need to be considered. - Mo toxicity thresholds varied widely in different soils and therefore soil properties need to be taken into account in order to assess the risk of Mo exposure.

  13. Radioecological investigations of phytocommunities higher water plant in upper Kiev water reservoir

    International Nuclear Information System (INIS)

    Pan'kov, I.V.; Volkova, E.N.; Shirokaya, Z.O.; Karapish, V.A.; Dremlyuga, S.V.

    1997-01-01

    The dose loads of the highest water plants it determined and ecological role of phytocommunities in radionuclides distribution and migration in water reservoir is shown. The ' critical zones ' for characteristic types of phytocommunities are determined. It is marked that radionuclides accumulation by macrophits depends on species and ecological group

  14. The xanthophylls in light-harvesting complex II of higher plants: light harvesting and triplet quenching.

    NARCIS (Netherlands)

    Peterman, E.J.G.; Gradinaru, C.C.; Calkoen, F.; Borst, J.C.; van Grondelle, R.; van Amerongen, H.

    1997-01-01

    A spectral and functional assignment of the xanthophylls in monomeric and trimeric light-harvesting complex II of green plants has been obtained using HPLC analysis of the pigment composition, laser-flash induced triplet- minus-singlet, fluorescence excitation, and absorption spectra. It is shown

  15. Arabidopsis transcription factors: genome-wide comparative analysis among eukaryotes.

    Science.gov (United States)

    Riechmann, J L; Heard, J; Martin, G; Reuber, L; Jiang, C; Keddie, J; Adam, L; Pineda, O; Ratcliffe, O J; Samaha, R R; Creelman, R; Pilgrim, M; Broun, P; Zhang, J Z; Ghandehari, D; Sherman, B K; Yu, G

    2000-12-15

    The completion of the Arabidopsis thaliana genome sequence allows a comparative analysis of transcriptional regulators across the three eukaryotic kingdoms. Arabidopsis dedicates over 5% of its genome to code for more than 1500 transcription factors, about 45% of which are from families specific to plants. Arabidopsis transcription factors that belong to families common to all eukaryotes do not share significant similarity with those of the other kingdoms beyond the conserved DNA binding domains, many of which have been arranged in combinations specific to each lineage. The genome-wide comparison reveals the evolutionary generation of diversity in the regulation of transcription.

  16. High-resolution confocal imaging of wall ingrowth deposition in plant transfer cells: Semi-quantitat