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Sample records for arabidopsis wrky2 transcription

  1. Isolation, Expression, and Promoter Analysis of GbWRKY2: A Novel Transcription Factor Gene from Ginkgo biloba

    Directory of Open Access Journals (Sweden)

    Yong-Ling Liao

    2015-01-01

    Full Text Available WRKY transcription factor is involved in multiple life activities including plant growth and development as well as biotic and abiotic responses. We identified 28 WRKY genes from transcriptome data of Ginkgo biloba according to conserved WRKY domains and zinc finger structure and selected three WRKY genes, which are GbWRKY2, GbWRKY16, and GbWRKY21, for expression pattern analysis. GbWRKY2 was preferentially expressed in flowers and strongly induced by methyl jasmonate. Here, we cloned the full-length cDNA and genomic DNA of GbWRKY2. The full-length cDNA of GbWRKY2 was 1,713 bp containing a 1,014 bp open reading frame encoding a polypeptide of 337 amino acids. The GbWRKY2 genomic DNA had one intron and two exons. The deduced GbWRKY2 contained one WRKY domain and one zinc finger motif. GbWRKY2 was classified into Group II WRKYs. Southern blot analysis revealed that GbWRKY2 was a single copy gene in G. biloba. Many cis-acting elements related to hormone and stress responses were identified in the 1,363 bp-length 5′-flanking sequence of GbWRKY2, including W-box, ABRE-motif, MYBCOREs, and PYRIMIDINE-boxes, revealing the molecular mechanism of upregulated expression of GbWRKY2 by hormone and stress treatments. Further functional characterizations in transiently transformed tobacco leaves allowed us to identify the region that can be considered as the minimal promoter.

  2. Isolation, Expression, and Promoter Analysis of GbWRKY2: A Novel Transcription Factor Gene from Ginkgo biloba

    Science.gov (United States)

    Liao, Yong-Ling; Shen, Yong-Bao; Chang, Jie; Zhang, Wei-Wei; Cheng, Shui-Yuan; Xu, Feng

    2015-01-01

    WRKY transcription factor is involved in multiple life activities including plant growth and development as well as biotic and abiotic responses. We identified 28 WRKY genes from transcriptome data of Ginkgo biloba according to conserved WRKY domains and zinc finger structure and selected three WRKY genes, which are GbWRKY2, GbWRKY16, and GbWRKY21, for expression pattern analysis. GbWRKY2 was preferentially expressed in flowers and strongly induced by methyl jasmonate. Here, we cloned the full-length cDNA and genomic DNA of GbWRKY2. The full-length cDNA of GbWRKY2 was 1,713 bp containing a 1,014 bp open reading frame encoding a polypeptide of 337 amino acids. The GbWRKY2 genomic DNA had one intron and two exons. The deduced GbWRKY2 contained one WRKY domain and one zinc finger motif. GbWRKY2 was classified into Group II WRKYs. Southern blot analysis revealed that GbWRKY2 was a single copy gene in G. biloba. Many cis-acting elements related to hormone and stress responses were identified in the 1,363 bp-length 5′-flanking sequence of GbWRKY2, including W-box, ABRE-motif, MYBCOREs, and PYRIMIDINE-boxes, revealing the molecular mechanism of upregulated expression of GbWRKY2 by hormone and stress treatments. Further functional characterizations in transiently transformed tobacco leaves allowed us to identify the region that can be considered as the minimal promoter. PMID:26351628

  3. 青花菜转录因子基因 BoWRKY2的克隆与表达分析%Cloning and expression analysis of a transcription factor gene BoWRKY2 from broccoli

    Institute of Scientific and Technical Information of China (English)

    蒋明; 陈贝贝; 管铭; 李金枝; 黄笑梅; 顾云吉

    2015-01-01

    Summary Broccoli ( Brassica oleracea var . italica) , which belongs to Cruciferae family , is a cash crop widely cultivated in China , and it is regarded as one of the most consumed vegetables in the world . The flower head of broccoli is rich in minerals , vitamins , fibers as well as anti‐oxidants , so it is recognized as a healthy vegetable with anti‐cancer properties . As a major broccoli production center in China , the average plantation areas reach to 8 000 hm2 in Taizhou of Zhejiang Province . However , broccoli cultivation suffered from plant diseases of downy mildew and stalk break which were caused by Hyaloperonospora parasitica and Sclerotinia sclerotiorum , respectively , resulting in yield and quality loss . WRKY transcription factors played important roles in plant stress responses , and WRKY domains were defined as an approximately 60‐amino acid motif named WRKYGQK as well as a zinc finger structure of C‐X4‐5‐C‐X2223‐H‐X1‐HattheirC‐terminus.TheWRKYdomainbindsspecificallytoDNAsequenceof(T)(T)TGAC(C/T) known as the W‐box which exists in defense‐related promoters . Enhanced disease resistance by overexpression of WRKY genes in different crop plants has been reported in recent years . Inthisstudy,aWRKYgenedesignatedasBoWRKY2,wasisolatedfromB.oleraceavar.italica.Basedon sequence analysis , expression patterns of BoWRKY2 were detected using reverse transcription‐polymerase chain reaction(RT‐PCR) methodwhilechallengedby H.parasiticaand S.sclerotiorum,respectively. The results showed that the genome DNA sequence was 1 507 bp in length with two introns and a complete coding sequence of 987 bp , and the length of two introns were 425 and 95 bp , respectively ; BoWRKY2 encoded 328 amino acids with a WRKYGQK residue and a zinc finger structure of C‐X5‐C‐X23‐H‐X1‐H . The WRKY domain located between 247 and 313 residues , and several DNA binding sites were found at sites of 66 , 67 , 69 , 71 , 74 , 281 , 282 , 283 and 317

  4. LeWRKY2基因的克隆及功能分析%Molecular Cloning and Analysis of LeWRKY2 Gene

    Institute of Scientific and Technical Information of China (English)

    孙清鹏; 李娜; 于涌鲲; 赵福宽; 万善霞; 潘金豹

    2012-01-01

    [目的]克隆番茄WRKY2转录因子,为研究番茄抗病反应的分子机理和分子育种奠定基础.[方法]根据克隆出的番茄LeWRKY2基因特异片段(GenBank登录号:EU755368.1),运用cDNA末端快速扩增(rapid amplification of cNDA ends,RACE)技术克隆番茄LeWRKY2 cDNA全长,并用生物信息学的方法对其进行分析.用实时荧光定量PCR方法检测番茄经JA、番茄灰霉菌(Botrytis cinerea)、放线菌酮(cycloheximide)刺激时LeWRKY2基因的表达情况.[结果]①从番茄中克隆到一条金长为1007 bp的cDNA序列,命名为LeWRKY2基因,阅读框471 bp,编码1 56个氨基酸.②LeWRKY2蛋白含有1个WRKY结构域和1个C2H2型锌指结构,可能具有转录、转录调控、信号传导功能.③100 μmol·L-1茉莉酸(jasmonic acid,JA)刺激番茄幼苗0-60 min时,LeWRKY2基因的相对含量与JA刺激时间成正比;而刺激60-150 min时,LeWRKY2基因的相对含量与JA刺激时间成反比;④番茄灰霉菌可以诱导LeWRKY2基因的的表达,且在4h时表达量达到最高;⑤LeWRKY2基因的转录产物的合成不依赖于蛋白质的从头合成.[结论]LeWRKY2是一种参与番茄防御反应的早期快速反应基因.%[Objective] Cloning of WRKY transcription factor from tomato can provide a basis for molecular mechanism of pathogen reaction in tomato. [Method] Using RT-PCR and RACE technology, the LeWRKY2 full length cDNA was cloned (GenBank accession: EU755368.1), and its function was predicted by bioinformatics tools. The real-time PCR technology was used to analyze the expression levels of LeWRKY2 gene when treated with JA, Botryiis cinerea and cycloheximide. [Result] The LeWRKY2 full length cDNA, consisted of 1 007 bp, was isolated from tomato. The bioinformatics analysis showed that it included an ORF of 471 bp. LeWRKY2 protein contained a WRKY domain and a C2H2 zinc finger motif, and it might have the function of transcription, transcriptional regulation and signal transduction. The LeWRKY

  5. 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.

  6. Cloning and expression pattern research under abiotic stress of theWRKY2 in potato%马铃薯WRKY2基因的克隆和非生物逆境下的表达模式

    Institute of Scientific and Technical Information of China (English)

    李立芹; 王西瑶

    2015-01-01

    Function of StWRKY2 has not been reported.Plant WRKY proteins are found as an important class of transcription factors in recent years,which are widely involved in biotic stress,abiotic stress and growth development regulation,and they are mainly divided into three groups.WRKY2 was cloned from potato by homology cloning, with length of the coding region 1 065 bp,encoding 355 amino acids by DNA sequencing.With the amino acid se-quence of StWRKY2 blasting in NCBI,19 homology amino acid sequences were selected to analysis conservative do-main.Amino acid analysis showed that the StWRKY2 contained 1 conserved WRKY domain (TTGACC)and be-longed to the second group of WRKY family members,and its zinc-finger structure was C-X5-C-X23 H-X-H.Phylog-eny tree results showed StWRKY2 was the most closest to SlWRKY7 (Solanum lycopersicum )with 96%similarity,and the similarity of a WRKY protein of tobacco was 86%.The protein-GST (glutathione-S-transferase) complex was obtained in Escherichia coli by using the method of prokaryotic expression.StWRKY2-GST could com-bine W-box in vivo by Electrophoretic Mobility Shift Assay analysis,but only GST protein could not combine W-box.StWRKY2-GST combination with W-box could be competed by cold probe(unlabeled probe).And the experi-ment results also showed that StWRKY2-GST could not combine mutation W-box,this suggested StWRKY2-GST combined W-box with specificity.Analysis of StWRKY2 expression level in the root,stem and leaf tissue through the real-time fluorescence quantitative PCR,the results showed that the gene was mainly expressed in the root.Next was leaf and stem.In order to further study the possible function of the gene,potato seeding from tissue culture were treated under 10 μmol/L low phosphorus,10 μmol/L low potassium,200 mmol/L NaCl,400 mmol/L PEG solution and 4 ℃ low-temperature treatment for 6 h,real-time fluorescence quantitative PCR showed that this gene expression level decreased significantly after low phosphorus

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

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

    2015-10-01

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

  8. Transcriptional Wiring of Cell Wall-Related Genes in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Marek Mutwil; Colin Ruprecht; Federico M. Giorgi; Martin Bringmann; Bj(o)rn Usadel; Staffan Persson

    2009-01-01

    Transcriptional coordination, or co-expression, of genes may signify functional relatedness of the correspond-ing proteins. For example, several genes involved in secondary cell wall cellulose biosynthesis are co-expressed with genes engaged in the synthesis of xylan, which is a major component of the secondary cell wall. To extend these types of anal-yses, we investigated the co-expression relationships of all Carbohydrate-Active enZYmes (CAZy)-related genes for Arabidopsis thaliana. Thus, the intention was to transcriptionally link different cell wall-related processes to each other, and also to other biological functions. To facilitate easy manual inspection, we have displayed these interactions as networks and matrices, and created a web-based interface (http://aranet.mpimp-golm.mpg.de/corecarb) containing downloadable files for all the transcriptional associations.

  9. Reference genes for normalizing transcription in diploid and tetraploid Arabidopsis.

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    Wang, Haibin; Wang, Jingjing; Jiang, Jiafu; Chen, Sumei; Guan, Zhiyong; Liao, Yuan; Chen, Fadi

    2014-10-27

    Published transcription data from a set of 19 diploid Arabidopsis thaliana and 5 tetraploid (3 allo- and 2 auto- tetraploid) Arabidopsis accessions were re-analysed to identify reliable reference genes for normalization purposes. Five conventional and 16 novel reference genes previously derived from microarray data covering a wide range of abundance in absolute expression levels in diploid A. thaliana Col-0 were employed. Transcript abundance was well conserved for all 21 potential reference genes in the diploid A. thaliana accessions, with geNorm and NormFinder analysis indicating that AT5G46630, AT1G13320, AT4G26410, AT5G60390 and AT5G08290 were the most stable. However, conservation was less good among the tetraploid accessions, with the transcription of seven of the 21 genes being undetectable in all allotetraploids. The most stable gene was AT5G46630, while AT1G13440 was the unstable one. Hence, the choice of reference gene(s) for A. thaliana is quite wide, but with respect to the analysis of transcriptomic data derived from the tetraploids, it is probably necessary to select more than one reference gene.

  10. Rethinking transcriptional activation in the Arabidopsis circadian clock.

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    Karl Fogelmark

    2014-07-01

    Full Text Available Circadian clocks are biological timekeepers that allow living cells to time their activity in anticipation of predictable daily changes in light and other environmental factors. The complexity of the circadian clock in higher plants makes it difficult to understand the role of individual genes or molecular interactions, and mathematical modelling has been useful in guiding clock research in model organisms such as Arabidopsis thaliana. We present a model of the circadian clock in Arabidopsis, based on a large corpus of published time course data. It appears from experimental evidence in the literature that most interactions in the clock are repressive. Hence, we remove all transcriptional activation found in previous models of this system, and instead extend the system by including two new components, the morning-expressed activator RVE8 and the nightly repressor/activator NOX. Our modelling results demonstrate that the clock does not need a large number of activators in order to reproduce the observed gene expression patterns. For example, the sequential expression of the PRR genes does not require the genes to be connected as a series of activators. In the presented model, transcriptional activation is exclusively the task of RVE8. Predictions of how strongly RVE8 affects its targets are found to agree with earlier interpretations of the experimental data, but generally we find that the many negative feedbacks in the system should discourage intuitive interpretations of mutant phenotypes. The dynamics of the clock are difficult to predict without mathematical modelling, and the clock is better viewed as a tangled web than as a series of loops.

  11. Rethinking transcriptional activation in the Arabidopsis circadian clock.

    Science.gov (United States)

    Fogelmark, Karl; Troein, Carl

    2014-07-01

    Circadian clocks are biological timekeepers that allow living cells to time their activity in anticipation of predictable daily changes in light and other environmental factors. The complexity of the circadian clock in higher plants makes it difficult to understand the role of individual genes or molecular interactions, and mathematical modelling has been useful in guiding clock research in model organisms such as Arabidopsis thaliana. We present a model of the circadian clock in Arabidopsis, based on a large corpus of published time course data. It appears from experimental evidence in the literature that most interactions in the clock are repressive. Hence, we remove all transcriptional activation found in previous models of this system, and instead extend the system by including two new components, the morning-expressed activator RVE8 and the nightly repressor/activator NOX. Our modelling results demonstrate that the clock does not need a large number of activators in order to reproduce the observed gene expression patterns. For example, the sequential expression of the PRR genes does not require the genes to be connected as a series of activators. In the presented model, transcriptional activation is exclusively the task of RVE8. Predictions of how strongly RVE8 affects its targets are found to agree with earlier interpretations of the experimental data, but generally we find that the many negative feedbacks in the system should discourage intuitive interpretations of mutant phenotypes. The dynamics of the clock are difficult to predict without mathematical modelling, and the clock is better viewed as a tangled web than as a series of loops.

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

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    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.

  13. Potential role of Arabidopsis PHP as an accessory subunit of the PAF1 transcriptional cofactor.

    Science.gov (United States)

    Park, Sunchung; Ek-Ramos, Maria Julissa; Oh, Sookyung; van Nocker, Steven

    2011-08-01

    Paf1C is a transcriptional cofactor that has been implicated in various transcription-associated mechanisms spanning initiation, elongation and RNA processing, and is important for multiple aspects of development in Arabidopsis. Our recent studies suggest Arabidopsis Paf1C is crucial for proper regulation of genes within H3K27me3-enriched chromatin, and that a protein named PHP may act as an accessory subunit of Paf1C that promotes this function.

  14. The Arabidopsis thaliana Nuclear Factor Y Transcription Factors

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

    2017-01-01

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

  15. Analysis of a transcription factor using transient assay in Arabidopsis protoplasts.

    Science.gov (United States)

    Iwata, Yuji; Lee, Mi-Hyun; Koizumi, Nozomu

    2011-01-01

    Regulation of gene expression by transcription factors is a fundamental mechanism in essentially all aspects of cellular processes. Transient expression assay of a reporter plasmid containing a reporter gene driven by a promoter of interest and an effector plasmid expressing a transcription factor has been a powerful tool for analyzing transcription factors. Here we present a protocol for polyethylene glycol (PEG)-mediated transformation of Arabidopsis protoplasts. It details preparation of protoplasts from Arabidopsis suspension cultured cells or leaves of soil-grown Arabidopsis plants and subsequent PEG-mediated transformation with reporter and effector plasmids. This protocol can be completed within 24 h from protoplast preparation to reporter assay. As an example, analysis of the membrane-bound transcription factor AtbZIP60 and its target BiP3 promoter is shown.

  16. A High-Throughput Screening System for Arabidopsis Transcription Factors and Its Application to Med25-Dependent Transcriptional Regulation

    Institute of Scientific and Technical Information of China (English)

    Bin Ou; Minami Matsui; Hong-Ya Gu; Li-Jia Qu; Kang-Quan Yin; Sai-Nan Liu; Yan Yang; Tren Gu; Jennifer Man Wing Hui; Li Zhang; Jin Miao; Youichi Kondou

    2011-01-01

    T The activities of transcription factors (TFs) require interactions with specific DNA sequences and other regulatory proteins. To detect such interactions in Arabidopsis, we developed a high-throughput screening system with a Gateway-compatible Gal4-AD-TF library of 1589 Arabidopsis TFs, which can be easily screened by mating-based yeast-one-hybrid (Y1H) and yeast-two-hybrid (Y2H) methods. The efficiency of the system was validated by examining two well-characterized TF-DNA and TF-protein interactions: the CHE-CCA1 promoter interaction by Y1H and NPR1-TGAs interactions by Y2H. We used this system to identify eight TFs that interact with a Mediator subunit, Med25, a key regulator in JA signaling. We identified five TFs that interacted with the GCC-box cis-element in the promoter of PDF1.2, a downstream gene of Med25. We found that three of these TFs, all from the AP2-EREBP family, interact directly both with Med25 and the GCC-box of PDF1.2, suggesting that Med25 regulates PDF1.2 expression through these three TFs.These results demonstrate that this high-throughput Y1H/Y2H screening system is an efficient tool for studying transcriptional regulation networks in Arabidopsis. This system will be available for other Arabidopsis researchers, and thus it provides a vital resource for the Arabidopsis community.

  17. Agrobacterium-Mediated In Planta Transformation of BcWRKY2 Gene of Maize Shoot Apical Meristem for Enhancing Resistance to Drought%农杆菌介导的BcWRKY2基因原位转化玉米茎尖的初步研究

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    曹士亮; 李文滨; 王石; 林忠平; 卢翠华

    2013-01-01

    利用农杆菌介导的原位转化方法将植物抗旱相关转录因子BcWRKY2基因导入优良玉米自交系郑58、K10、黄早四和M017.采用正交设计对玉米品种、菌液浓度、乙酰丁香酮浓度(AS)、真空处理时间和表面活性剂Silwet-77浓度进行了优化.研究结果表明,各因素对转化率影响顺序依次是菌液浓度>品种> AS浓度>真空处理时间>Silwet-77浓度.确定了最优转化条件为品种郑58、真空处理时间20min、菌液浓度为OD600=0.9、AS浓度100μmol/L、Silwet-77浓度0.05%.PCR及RT-PCR分子检测试验说明,BcWRKY2基因已经整合到玉米基因组中,并且得到表达.%In this study,drought tolerance related transcription factor BcWRKY2 gene was transformed into elite maize inbred lines(Zheng 58,K10,Huangzaosi,and Mo17) by in planta transformation mediated by Agrobacterium.Five factors,including varieties,concentration of Agrobacterium,concentration of acetosyringone (AS),time of vacuum processing,concentration of surfactant Silwet-77 were optimized by orthogonal tests.The result showed that the importance of factors ranged as the concentration of Agrobacterium > varieties > the concentration of acetosyringone (AS) > the time of vacuum processing > the concentration of surfactant Silwet-77.the combination of variety Zheng 58,OD600 value 0.9,100μmol/L acetosyringone,20min vacuum processing and 0.05% (v/v) Silwet-77 was optimal.The herbicide-resistant plants were further detected by PCR and RT-PCR.It showed that BcWRKY2 gene was inserted into the genome of the transgenic plants preliminarily.

  18. JUNGBRUNNEN1, a Reactive Oxygen Species–Responsive NAC Transcription Factor, Regulates Longevity in Arabidopsis

    NARCIS (Netherlands)

    Wu, A.; Devi Allu, A.; Garapati, P.; Siddiqui, H.; Dortay, H.; Zanor, M.I.; Amparo Asensi-Fabado, M.; Munne´ -Bosch, S.; Antonio, C.; Tohge, T.; Fernie, A.R.; Kaufmann, K.; Xue, G.P.; Mueller-Roeber, B.; Balazadeh, S.

    2012-01-01

    The transition from juvenility through maturation to senescence is a complex process that involves the regulation of longevity. Here, we identify JUNGBRUNNEN1 (JUB1), a hydrogen peroxide (H2O2)-induced NAC transcription factor, as a central longevity regulator in Arabidopsis thaliana. JUB1 overexpre

  19. Expression and Protein Interaction Analyses Reveal Combinatorial Interactions of LBD Transcription Factors During Arabidopsis Pollen Development.

    Science.gov (United States)

    Kim, Mirim; Kim, Min-Jung; Pandey, Shashank; Kim, Jungmook

    2016-11-01

    LATERAL ORGAN BOUNDARIES DOMAIN (LBD) transcription factor gene family members play key roles in diverse aspects of plant development. LBD10 and LBD27 have been shown to be essential for pollen development in Arabidopsis thaliana. From the previous RNA sequencing (RNA-Seq) data set of Arabidopsis pollen, we identified the mRNAs of LBD22, LBD25 and LBD36 in addition to LBD10 and LBD27 in Arabidopsis pollen. Here we conducted expression and cellular analysis using GFP:GUS (green fluorescent protein:β-glucuronidase) reporter gene and subcellular localization assays using LBD:GFP fusion proteins expressed under the control of their own promoters in Arabidopsis. We found that these LBD proteins display spatially and temporally distinct and overlapping expression patterns during pollen development. Bimolecular fluorescence complementation and GST (glutathione S-transferase) pull-down assays demonstrated that protein-protein interactions occur among the LBDs exhibiting overlapping expression during pollen development. We further showed that LBD10, LBD22, LBD25, LBD27 and LBD36 interact with each other to form heterodimers, which are localized to the nucleus in Arabidopsis protoplasts. Taken together, these results suggest that combinatorial interactions among LBD proteins may be important for their function in pollen development in Arabidopsis.

  20. A Genome-Scale Resource for the Functional Characterization of Arabidopsis Transcription Factors

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    Jose L. Pruneda-Paz

    2014-07-01

    Full Text Available Extensive transcriptional networks play major roles in cellular and organismal functions. Transcript levels are in part determined by the combinatorial and overlapping functions of multiple transcription factors (TFs bound to gene promoters. Thus, TF-promoter interactions provide the basic molecular wiring of transcriptional regulatory networks. In plants, discovery of the functional roles of TFs is limited by an increased complexity of network circuitry due to a significant expansion of TF families. Here, we present the construction of a comprehensive collection of Arabidopsis TFs clones created to provide a versatile resource for uncovering TF biological functions. We leveraged this collection by implementing a high-throughput DNA binding assay and identified direct regulators of a key clock gene (CCA1 that provide molecular links between different signaling modules and the circadian clock. The resources introduced in this work will significantly contribute to a better understanding of the transcriptional regulatory landscape of plant genomes.

  1. Genome wide analysis of stress responsive WRKY transcription factors in Arabidopsis thaliana

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    Shaiq Sultan

    2016-04-01

    Full Text Available WRKY transcription factors are a class of DNA-binding proteins that bind with a specific sequence C/TTGACT/C known as W-Box found in promoters of genes which are regulated by these WRKYs. From previous studies, 43 different stress responsive WRKY transcription factors in Arabidopsis thaliana, identified and then categorized in three groups viz., abiotic, biotic and both of these stresses. A comprehensive genome wide analysis including chromosomal localization, gene structure analysis, multiple sequence alignment, phylogenetic analysis and promoter analysis of these WRKY genes was carried out in this study to determine the functional homology in Arabidopsis. This analysis led to the classification of these WRKY family members into 3 major groups and subgroups and showed evolutionary relationship among these groups on the base of their functional WRKY domain, chromosomal localization and intron/exon structure. The proposed groups of these stress responsive WRKY genes and annotation based on their position on chromosomes can also be explored to determine their functional homology in other plant species in relation to different stresses. The result of the present study provides indispensable genomic information for the stress responsive WRKY transcription factors in Arabidopsis and will pave the way to explain the precise role of various AtWRKYs in plant growth and development under stressed conditions.

  2. Deciphering the Molecular Mechanisms Underpinning the Transcriptional Control of Gene Expression by Master Transcriptional Regulators in Arabidopsis Seed.

    Science.gov (United States)

    Baud, Sébastien; Kelemen, Zsolt; Thévenin, Johanne; Boulard, Céline; Blanchet, Sandrine; To, Alexandra; Payre, Manon; Berger, Nathalie; Effroy-Cuzzi, Delphine; Franco-Zorrilla, Jose Manuel; Godoy, Marta; Solano, Roberto; Thevenon, Emmanuel; Parcy, François; Lepiniec, Loïc; Dubreucq, Bertrand

    2016-06-01

    In Arabidopsis (Arabidopsis thaliana), transcriptional control of seed maturation involves three related regulators with a B3 domain, namely LEAFY COTYLEDON2 (LEC2), ABSCISIC ACID INSENSITIVE3 (ABI3), and FUSCA3 (ABI3/FUS3/LEC2 [AFLs]). Although genetic analyses have demonstrated partially overlapping functions of these regulators, the underlying molecular mechanisms remained elusive. The results presented here confirmed that the three proteins bind RY DNA elements (with a 5'-CATG-3' core sequence) but with different specificities for flanking nucleotides. In planta as in the moss Physcomitrella patens protoplasts, the presence of RY-like (RYL) elements is necessary but not sufficient for the regulation of the OLEOSIN1 (OLE1) promoter by the B3 AFLs. G box-like domains, located in the vicinity of the RYL elements, also are required for proper activation of the promoter, suggesting that several proteins are involved. Consistent with this idea, LEC2 and ABI3 showed synergistic effects on the activation of the OLE1 promoter. What is more, LEC1 (a homolog of the NF-YB subunit of the CCAAT-binding complex) further enhanced the activation of this target promoter in the presence of LEC2 and ABI3. Finally, recombinant LEC1 and LEC2 proteins produced in Arabidopsis protoplasts could form a ternary complex with NF-YC2 in vitro, providing a molecular explanation for their functional interactions. Taken together, these results allow us to propose a molecular model for the transcriptional regulation of seed genes by the L-AFL proteins, based on the formation of regulatory multiprotein complexes between NF-YBs, which carry a specific aspartate-55 residue, and B3 transcription factors.

  3. Transcription factor movement and tissue patterning in Arabidopsis root meristem

    NARCIS (Netherlands)

    Long, Y.

    2015-01-01

    Cell-cell communication is key to coordinated cellular functions in multicellular organisms. In addition to the signaling molecules found in animals, plants also frequently recruit mobile transcription factors to deliver positional information. The best studied example is SHORT-ROOT (SHR), a transcr

  4. The role of transcriptional coactivator ADA2b in Arabidopsis abiotic stress responses.

    Science.gov (United States)

    Vlachonasios, Konstantinos E; Kaldis, Athanasios; Nikoloudi, Adriana; Tsementzi, Despoina

    2011-10-01

    Plant growth and crop production can be greatly affected by common environmental stresses such as drought, high salinity and low temperatures. Gene expression is affected by several abiotic stresses. Stress-inducible genes are regulated by transcription factors and epigenetic mechanisms such as histone modifications. In this Mini-Review, we have explored the role of transcriptional adaptor ADA2b in Arabidopsis responses to abiotic stress. ADA2b is required for the expression of genes involved in abiotic stress either by controlling H3 and H4 acetylation in the case of salt stress or affecting nucleosome occupancy in low temperatures response.

  5. The Transcriptional Coregulator LEUNIG_HOMOLOG Inhibits Light-Dependent Seed Germination in Arabidopsis.

    Science.gov (United States)

    Lee, Nayoung; Park, Jeongmoo; Kim, Keunhwa; Choi, Giltsu

    2015-08-01

    PHYTOCHROME-INTERACTING FACTOR1 (PIF1) is a basic helix-loop-helix transcription factor that inhibits light-dependent seed germination in Arabidopsis thaliana. However, it remains unclear whether PIF1 requires other factors to regulate its direct targets. Here, we demonstrate that LEUNIG_HOMOLOG (LUH), a Groucho family transcriptional corepressor, binds to PIF1 and coregulates its targets. Not only are the transcriptional profiles of the luh and pif1 mutants remarkably similar, more than 80% of the seeds of both genotypes germinate in the dark. We show by chromatin immunoprecipitation that LUH binds a subset of PIF1 targets in a partially PIF1-dependent manner. Unexpectedly, we found LUH binds and coregulates not only PIF1-activated targets but also PIF1-repressed targets. Together, our results indicate LUH functions with PIF1 as a transcriptional coregulator to inhibit seed germination.

  6. Transcriptional analysis of the Arabidopsis ovule by massively parallel signature sequencing

    Science.gov (United States)

    Sánchez-León, Nidia; Arteaga-Vázquez, Mario; Alvarez-Mejía, César; Mendiola-Soto, Javier; Durán-Figueroa, Noé; Rodríguez-Leal, Daniel; Rodríguez-Arévalo, Isaac; García-Campayo, Vicenta; García-Aguilar, Marcelina; Olmedo-Monfil, Vianey; Arteaga-Sánchez, Mario; Martínez de la Vega, Octavio; Nobuta, Kan; Vemaraju, Kalyan; Meyers, Blake C.; Vielle-Calzada, Jean-Philippe

    2012-01-01

    The life cycle of flowering plants alternates between a predominant sporophytic (diploid) and an ephemeral gametophytic (haploid) generation that only occurs in reproductive organs. In Arabidopsis thaliana, the female gametophyte is deeply embedded within the ovule, complicating the study of the genetic and molecular interactions involved in the sporophytic to gametophytic transition. Massively parallel signature sequencing (MPSS) was used to conduct a quantitative large-scale transcriptional analysis of the fully differentiated Arabidopsis ovule prior to fertilization. The expression of 9775 genes was quantified in wild-type ovules, additionally detecting >2200 new transcripts mapping to antisense or intergenic regions. A quantitative comparison of global expression in wild-type and sporocyteless (spl) individuals resulted in 1301 genes showing 25-fold reduced or null activity in ovules lacking a female gametophyte, including those encoding 92 signalling proteins, 75 transcription factors, and 72 RNA-binding proteins not reported in previous studies based on microarray profiling. A combination of independent genetic and molecular strategies confirmed the differential expression of 28 of them, showing that they are either preferentially active in the female gametophyte, or dependent on the presence of a female gametophyte to be expressed in sporophytic cells of the ovule. Among 18 genes encoding pentatricopeptide-repeat proteins (PPRs) that show transcriptional activity in wild-type but not spl ovules, CIHUATEOTL (At4g38150) is specifically expressed in the female gametophyte and necessary for female gametogenesis. These results expand the nature of the transcriptional universe present in the ovule of Arabidopsis, and offer a large-scale quantitative reference of global expression for future genomic and developmental studies. PMID:22442422

  7. Transcriptional analysis of the Arabidopsis ovule by massively parallel signature sequencing.

    Science.gov (United States)

    Sánchez-León, Nidia; Arteaga-Vázquez, Mario; Alvarez-Mejía, César; Mendiola-Soto, Javier; Durán-Figueroa, Noé; Rodríguez-Leal, Daniel; Rodríguez-Arévalo, Isaac; García-Campayo, Vicenta; García-Aguilar, Marcelina; Olmedo-Monfil, Vianey; Arteaga-Sánchez, Mario; de la Vega, Octavio Martínez; Nobuta, Kan; Vemaraju, Kalyan; Meyers, Blake C; Vielle-Calzada, Jean-Philippe

    2012-06-01

    The life cycle of flowering plants alternates between a predominant sporophytic (diploid) and an ephemeral gametophytic (haploid) generation that only occurs in reproductive organs. In Arabidopsis thaliana, the female gametophyte is deeply embedded within the ovule, complicating the study of the genetic and molecular interactions involved in the sporophytic to gametophytic transition. Massively parallel signature sequencing (MPSS) was used to conduct a quantitative large-scale transcriptional analysis of the fully differentiated Arabidopsis ovule prior to fertilization. The expression of 9775 genes was quantified in wild-type ovules, additionally detecting >2200 new transcripts mapping to antisense or intergenic regions. A quantitative comparison of global expression in wild-type and sporocyteless (spl) individuals resulted in 1301 genes showing 25-fold reduced or null activity in ovules lacking a female gametophyte, including those encoding 92 signalling proteins, 75 transcription factors, and 72 RNA-binding proteins not reported in previous studies based on microarray profiling. A combination of independent genetic and molecular strategies confirmed the differential expression of 28 of them, showing that they are either preferentially active in the female gametophyte, or dependent on the presence of a female gametophyte to be expressed in sporophytic cells of the ovule. Among 18 genes encoding pentatricopeptide-repeat proteins (PPRs) that show transcriptional activity in wild-type but not spl ovules, CIHUATEOTL (At4g38150) is specifically expressed in the female gametophyte and necessary for female gametogenesis. These results expand the nature of the transcriptional universe present in the ovule of Arabidopsis, and offer a large-scale quantitative reference of global expression for future genomic and developmental studies.

  8. Identification of transcription-factor genes expressed in the Arabidopsis female gametophyte

    Directory of Open Access Journals (Sweden)

    Kang Il-Ho

    2010-06-01

    Full Text Available Abstract Background In flowering plants, the female gametophyte is typically a seven-celled structure with four cell types: the egg cell, the central cell, the synergid cells, and the antipodal cells. These cells perform essential functions required for double fertilization and early seed development. Differentiation of these distinct cell types likely involves coordinated changes in gene expression regulated by transcription factors. Therefore, understanding female gametophyte cell differentiation and function will require dissection of the gene regulatory networks operating in each of the cell types. These efforts have been hampered because few transcription factor genes expressed in the female gametophyte have been identified. To identify such genes, we undertook a large-scale differential expression screen followed by promoter-fusion analysis to detect transcription-factor genes transcribed in the Arabidopsis female gametophyte. Results Using quantitative reverse-transcriptase PCR, we analyzed 1,482 Arabidopsis transcription-factor genes and identified 26 genes exhibiting reduced mRNA levels in determinate infertile 1 mutant ovaries, which lack female gametophytes, relative to ovaries containing female gametophytes. Spatial patterns of gene transcription within the mature female gametophyte were identified for 17 transcription-factor genes using promoter-fusion analysis. Of these, ten genes were predominantly expressed in a single cell type of the female gametophyte including the egg cell, central cell and the antipodal cells whereas the remaining seven genes were expressed in two or more cell types. After fertilization, 12 genes were transcriptionally active in the developing embryo and/or endosperm. Conclusions We have shown that our quantitative reverse-transcriptase PCR differential-expression screen is sufficiently sensitive to detect transcription-factor genes transcribed in the female gametophyte. Most of the genes identified in this

  9. Transcriptional Regulation of Arabidopsis in Response to Salt Stress

    Institute of Scientific and Technical Information of China (English)

    Zhulong Chan

    2012-01-01

    Salt stress is a major factor limiting agricultural productivity worldwide.Adaptations to salt stress include avoidance by reduced sodium uptake,sequestration of toxic sodium ions away from the cytoplasm,or production of compatible solutes or osmoprotectants to reduce molecular disruption.Approaches to engineer salt stress resistance have included regulation of ion transport through introduction of Na+/H+ antiporter; synthesis of compatible solutes; or the introduction of transcription factors regulating expression of stress-responsive genes.On the other hand,naturally occurring variation among wild-type populations of plants also can be used to understand plant adaptive responses to their environments.In this study,we compared phenotypic and transcriptomic effects of constitutive expression of genes intended to confer salt stress tolerance by three different mechanisms:a transcription factor,CBF3/DREB1a; a metabolic gene,M6PR,for mannitol biosynthesis; and the Na+/H+ antiporter,SOS1.In the absence of salt,M6PR and SOS1 lines performed comparably with wild type; CBF3 lines exhibited dwarfing as reported previously.All three transgenes conferred fitness advantage when subjected to 100 mmol/L NaCI in the growth chamber.CBF3 and M6PR affected transcription of numerous abiotic stress-related genes as measured by Affymetrix microarray analysis.M6PR additionally modified expression of biotic stress and oxidative stress genes.Transcriptional effects of SOS1 were smaller and primarily limited to redox-related genes.In addition,we compared natural variations in salt tolerance between Ler and Sha ecotypes based on their responses to salt treatments and the results indicated that Ler was salt-sensitive,but Sha,which obtained a truncated RAS1 protein,was salt-tolerant.Transcriptome analysis revealed that many genes involved in secondary metabolism,photosynthesis,and protein synthesis were mainly down-regulated by salinity effects,while transposable element genes,microRNA and

  10. Ectopic expression of MYB46 identifies transcriptional regulatory genes involved in secondary wall biosynthesis in Arabidopsis.

    Science.gov (United States)

    Ko, Jae-Heung; Kim, Won-Chan; Han, Kyung-Hwan

    2009-11-01

    MYB46 functions as a transcriptional switch that turns on the genes necessary for secondary wall biosynthesis. Elucidating the transcriptional regulatory network immediately downstream of MYB46 is crucial to our understanding of the molecular and biochemical processes involved in the biosynthesis and deposition of secondary walls in plants. To gain insights into MYB46-mediated transcriptional regulation, we first established an inducible secondary wall thickening system in Arabidopsis by expressing MYB46 under the control of dexamethasone-inducible promoter. Then, we used an ATH1 GeneChip microarray and Illumina digital gene expression system to obtain a series of transcriptome profiles with regard to the induction of secondary wall development. These analyses allowed us to identify a group of transcription factors whose expression coincided with or preceded the induction of secondary wall biosynthetic genes. A transient transcriptional activation assay was used to confirm the hierarchical relationships among the transcription factors in the network. The in vivo assay showed that MYB46 transcriptionally activates downstream target transcription factors, three of which (AtC3H14, MYB52 and MYB63) were shown to be able to activate secondary wall biosynthesis genes. AtC3H14 activated the transcription of all of the secondary wall biosynthesis genes tested, suggesting that AtC3H14 may be another master regulator of secondary wall biosynthesis. The transcription factors identified here may include direct activators of secondary wall biosynthesis genes. The present study discovered novel hierarchical relationships among the transcription factors involved in the transcriptional regulation of secondary wall biosynthesis, and generated several testable hypotheses.

  11. Control of trichome formation in Arabidopsis by poplar single-repeat R3 MYB transcription factors

    Directory of Open Access Journals (Sweden)

    Limei eZhou

    2014-06-01

    Full Text Available In Arabidopsis, trichome formation is regulated by the interplay of R3 MYBs and several others transcription factors including the WD40-repeat protein TRANSPARENT TESTA GLABRA1 (TTG1, the R2R3 MYB transcription factor GLABRA1 (GL1, the bHLH transcription factor GLABRA3 (GL3 or ENHANCER OF GLABRA3 (EGL3, and the homeodomain protein GLABRA2 (GL2. R3 MYBs including TRICHOMELESS1 (TCL1, TRYPTICHON (TRY, CAPRICE (CPC, ENHANCER OF TRY AND CPC1 (ETC1, ETC2 and ETC3 negatively regulate trichome formation by competing with GL1 for binding GL3 or EGL3, thus blocking the formation of TTG1-GL3/EGL3-GL1, an activator complex required for the activation of the trichome positive regulator gene GL2. However, it is largely unknown if R3 MYBs in other plant species especially woody plants have similar functions. By BLASTing the Populus trichocarpa protein database using the entire amino acid sequence of TCL1, an Arabidopsis R3 MYB transcription factor, we identified a total of eight R3 MYB transcription factor genes in poplar, namely Populus trichocarpa TRICHOMELESS1through 8 (PtrTCL1-PtrTCL8. The amino acid signature required for interacting with bHLH transcription factors and the amino acids required for cell-to-cell movement of R3 MYBs are not fully conserved in all PtrTCLs. When tested in Arabidopsis protoplasts, however, all PtrTCL interacted with GL3. Expressing each of the eight PtrTCLs genes in Arabidopsis resulted in either glabrous phenotypes or plants with reduced trichome numbers, and expression levels of GL2 in all transgenic plants tested were greatly reduced. Expression of PtrTCL1 under the control of TCL1 native promoter almost completely complemented the mutant phenotype of tcl. In contrast, expression of PtrTCL1 under the control of TRY native promoter in the try mutant, or under the control of CPC native promoter in the cpc mutant resulted in glabrous phenotypes, suggesting that PtrTCL1 functions similarly to TCL1, but not TRY and CPC.

  12. The transcriptional response of Arabidopsis leaves to Fe deficiency

    Directory of Open Access Journals (Sweden)

    Jorge eRodriguez-Celma

    2013-07-01

    Full Text Available Due to its ease to donate or accept electrons, iron (Fe plays a crucial role in respiration and metabolism, including tetrapyrrole synthesis, in virtually all organisms. In plants, Fe is a component of the photosystems and thus essential for photosynthesis. Fe deficiency compromises chlorophyll (Chl synthesis, leading to interveinal chlorosis in developing leaves and decreased photosynthetic activity. To gain insights into the responses of photosynthetically active cells to Fe deficiency, we conducted transcriptional profiling experiments on leaves from Fe-sufficient and Fe-deficient plants using the RNA-seq technology. As anticipated, genes associated with photosynthesis and tetrapyrrole metabolism were dramatically down-regulated by Fe deficiency. A sophisticated response comprising the down-regulation of HEMA1 and NYC1, which catalyze the first committed step in tetrapyrrole biosynthesis and the conversion of Chl b to Chl a at the commencement of Chl breakdown, respectively, and the up-regulation of CGLD27, which is conserved in plastid-containing organisms and putatively involved in xanthophyll biosynthesis, indicates a carefully orchestrated balance of potentially toxic tetrapyrrole intermediates and functional end products to avoid photo-oxidative damage. Comparing the responses to Fe deficiency in leaves to that in roots confirmed subgroup 1b bHLH transcription factors and POPEYE/BRUTUS as important regulators of Fe homeostasis in both leaf and root cells, and indicated six novel players with putative roles in Fe homeostasis that were highly expressed in leaves and roots and greatly induced by Fe deficiency. The data further revealed down-regulation of organ-specific subsets of genes encoding ribosomal proteins, which may be indicative of a change in ribosomal composition that could bias translation. It is concluded that Fe deficiency causes a massive reorganization of plastid activity, which is adjusting leaf function to the availability

  13. The transcriptional response of Arabidopsis leaves to Fe deficiency.

    Science.gov (United States)

    Rodríguez-Celma, Jorge; Pan, I Chun; Li, Wenfeng; Lan, Ping; Buckhout, Thomas J; Schmidt, Wolfgang

    2013-01-01

    Due to its ease to donate or accept electrons, iron (Fe) plays a crucial role in respiration and metabolism, including tetrapyrrole synthesis, in virtually all organisms. In plants, Fe is a component of the photosystems and thus essential for photosynthesis. Fe deficiency compromises chlorophyll (Chl) synthesis, leading to interveinal chlorosis in developing leaves and decreased photosynthetic activity. To gain insights into the responses of photosynthetically active cells to Fe deficiency, we conducted transcriptional profiling experiments on leaves from Fe-sufficient and Fe-deficient plants using the RNA-seq technology. As anticipated, genes associated with photosynthesis and tetrapyrrole metabolism were dramatically down-regulated by Fe deficiency. A sophisticated response comprising the down-regulation of HEMA1 and NYC1, which catalyze the first committed step in tetrapyrrole biosynthesis and the conversion of Chl b to Chl a at the commencement of Chl breakdown, respectively, and the up-regulation of CGLD27, which is conserved in plastid-containing organisms and putatively involved in xanthophyll biosynthesis, indicates a carefully orchestrated balance of potentially toxic tetrapyrrole intermediates and functional end products to avoid photo-oxidative damage. Comparing the responses to Fe deficiency in leaves to that in roots confirmed subgroup 1b bHLH transcription factors and POPEYE/BRUTUS as important regulators of Fe homeostasis in both leaf and root cells, and indicated six novel players with putative roles in Fe homeostasis that were highly expressed in leaves and roots and greatly induced by Fe deficiency. The data further revealed down-regulation of organ-specific subsets of genes encoding ribosomal proteins, which may be indicative of a change in ribosomal composition that could bias translation. It is concluded that Fe deficiency causes a massive reorganization of plastid activity, which is adjusting leaf function to the availability of Fe.

  14. Overexpression of the Rap2.4f transcriptional factor in Arabidopsis promotes leaf senescence

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Senescence is a complex and highly regulated process. Leaf senescence is influenced by endogenous developmental and external environmental signals. In this work, we found that expression of an Ap2/DREB-type transcription factor gene, Arabidopsis Rap2.4f (At4g28140), was upregulated by salt, mannitol, and dark treatments. Constitutively overexpressing Rap2.4f under the control of the CaMV 35S promoter led to an increased chlorophyll degradation rate and upregulation of many senescence-associated genes in the transgenic Arabidopsis lines. Our results show that Rap2.4f is a positive regulator of senescence, promoting both developmental and dark-induced leaf senescence.

  15. Characterization and pilot functional study of a rootspecific MYB transcription factor of Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    An MYB transcription factor (AtMYB305) ofArabidopsis was structurally characterized. The biochemical activity of the protein was tested and its in vivo function was preliminarily analyzed. AtMYB305 contains two imperfect repeats (R2, R3) in its DNA binding domain. Gel mobility shift assay demonstrated that GST-AtMYB305 fusion protein bound specifically to the DNA fragment that included a consensus MYB recognition sequence (TAACTG). Overexpression of AtMYB305 in the fission yeast caused the formation of elongated cells with one condensed nucleus.Semi-quantitative RT-PCR analysis revealed that AtMYB305was expressed specifically in the roots of Arabidopsis.

  16. Comprehensive transcriptional profiling of NaCl-stressed Arabidopsis roots reveals novel classes of responsive genes

    Directory of Open Access Journals (Sweden)

    Deyholos Michael K

    2006-10-01

    Full Text Available Abstract Background Roots are an attractive system for genomic and post-genomic studies of NaCl responses, due to their primary importance to agriculture, and because of their relative structural and biochemical simplicity. Excellent genomic resources have been established for the study of Arabidopsis roots, however, a comprehensive microarray analysis of the root transcriptome following NaCl exposure is required to further understand plant responses to abiotic stress and facilitate future, systems-based analyses of the underlying regulatory networks. Results We used microarrays of 70-mer oligonucleotide probes representing 23,686 Arabidopsis genes to identify root transcripts that changed in relative abundance following 6 h, 24 h, or 48 h of hydroponic exposure to 150 mM NaCl. Enrichment analysis identified groups of structurally or functionally related genes whose members were statistically over-represented among up- or down-regulated transcripts. Our results are consistent with generally observed stress response themes, and highlight potentially important roles for underappreciated gene families, including: several groups of transporters (e.g. MATE, LeOPT1-like; signalling molecules (e.g. PERK kinases, MLO-like receptors, carbohydrate active enzymes (e.g. XTH18, transcription factors (e.g. members of ZIM, WRKY, NAC, and other proteins (e.g. 4CL-like, COMT-like, LOB-Class 1. We verified the NaCl-inducible expression of selected transcription factors and other genes by qRT-PCR. Conclusion Micorarray profiling of NaCl-treated Arabidopsis roots revealed dynamic changes in transcript abundance for at least 20% of the genome, including hundreds of transcription factors, kinases/phosphatases, hormone-related genes, and effectors of homeostasis, all of which highlight the complexity of this stress response. Our identification of these transcriptional responses, and groups of evolutionarily related genes with either similar or divergent

  17. In Silico Identification of Co-transcribed Core Cell Cycle Regulators and Transcription Factors in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Regulatory networks involving transcription factors and core cell cycle regulators are expected to play crucial roles in plant growth and development. In this report, we describe the identification of two groups of co-transcribed core cell cycle regulators and transcription factors via a two-step in silico screening. The core cell cycle regulators include TARDY ASYNCHRONOUS MEIOSIS (CYCA1;2), CYCB1;1, CYCB2;1, CDKB1;2, and CDKB2;2 while the transcription factors include CURLY LEAF, AINTEGUMENTA, a MYB protein, two Forkhead-associated domain proteins, and a SCARECROW family protein. Promoter analysis revealed a potential web of cross- and self-regulations among the identified proteins. Because one criterion for screening for these genes is that they are predominantly transcribed in young organs but not in mature organs, these genes are likely to be particularly involved in Arabidopsis organ growth.

  18. HORMONOMETER: a tool for discerning transcript signatures of hormone action in the Arabidopsis transcriptome.

    Science.gov (United States)

    Volodarsky, Dina; Leviatan, Noam; Otcheretianski, Andrei; Fluhr, Robert

    2009-08-01

    Plant hormones regulate growth and responses to environmental change. Hormone action ultimately modifies cellular physiological processes and gene activity. To facilitate transcriptome evaluation of novel mutants and environmental responses, there is a need to rapidly assess the possible contribution of hormone action to changes in the levels of gene transcripts. We developed a vector-based algorithm that rapidly compares lists of transcripts yielding correlation values. The application as described here, called HORMONOMETER, was used to analyze hormone-related activity in a transcriptome of Arabidopsis (Arabidopsis thaliana). The veracity of the resultant analysis was established by comparison with cognate and noncognate hormone transcriptomes as well as with mutants and selected plant-environment interactions. The HORMONOMETER accurately predicted correlations between hormone action and biosynthetic mutants for which transcriptome data are available. A high degree of correlation was detected between many hormones, particularly at early time points of hormone action. Unforeseen complexity was detected in the analysis of mutants and in plant-herbivore interactions. The HORMONOMETER provides a diagnostic tool for evaluating the physiological state of being of the plant from the point of view of transcripts regulated by hormones and yields biological insight into the multiple response components that enable plant adaptation to the environment. A Web-based interface has been developed to facilitate external interfacing with this platform.

  19. Analysis of functional redundancies within the Arabidopsis TCP transcription factor family.

    Science.gov (United States)

    Danisman, Selahattin; van Dijk, Aalt D J; Bimbo, Andrea; van der Wal, Froukje; Hennig, Lars; de Folter, Stefan; Angenent, Gerco C; Immink, Richard G H

    2013-12-01

    Analyses of the functions of TEOSINTE-LIKE1, CYCLOIDEA, and PROLIFERATING CELL FACTOR1 (TCP) transcription factors have been hampered by functional redundancy between its individual members. In general, putative functionally redundant genes are predicted based on sequence similarity and confirmed by genetic analysis. In the TCP family, however, identification is impeded by relatively low overall sequence similarity. In a search for functionally redundant TCP pairs that control Arabidopsis leaf development, this work performed an integrative bioinformatics analysis, combining protein sequence similarities, gene expression data, and results of pair-wise protein-protein interaction studies for the 24 members of the Arabidopsis TCP transcription factor family. For this, the work completed any lacking gene expression and protein-protein interaction data experimentally and then performed a comprehensive prediction of potential functional redundant TCP pairs. Subsequently, redundant functions could be confirmed for selected predicted TCP pairs by genetic and molecular analyses. It is demonstrated that the previously uncharacterized class I TCP19 gene plays a role in the control of leaf senescence in a redundant fashion with TCP20. Altogether, this work shows the power of combining classical genetic and molecular approaches with bioinformatics predictions to unravel functional redundancies in the TCP transcription factor family.

  20. Transcriptional regulation of LUX by CBF1 mediates cold input to the circadian clock in Arabidopsis.

    Science.gov (United States)

    Chow, Brenda Y; Sanchez, Sabrina E; Breton, Ghislain; Pruneda-Paz, Jose L; Krogan, Naden T; Kay, Steve A

    2014-07-07

    Circadian clocks allow organisms to anticipate daily changes in the environment to enhance overall fitness. Transcription factors (TFs) play a prominent role in the molecular mechanism but are incompletely described possibly due to functional redundancy, gene family proliferation, and/or lack of context-specific assays. To overcome these, we performed a high-throughput yeast one-hybrid screen using the LUX ARRYHTHMO (LUX) gene promoter as bait against an Arabidopsis TF library. LUX is a unique gene because its mutation causes severe clock defects and transcript maintains high-amplitude cycling in the cold. We report the well-characterized cold-inducible C-repeat (CRT)/drought-responsive element (DRE) binding factor CBF1/DREB1b is a transcriptional regulator of LUX. We show that CBF1 binds the CRT in the LUX promoter, and both genes overlap in temporal and spatial expression. CBF1 overexpression causes upregulation of LUX and also alters other clock gene transcripts. LUX promoter regions including the CRT and Evening Element (EE) are sufficient for high-amplitude transcriptional cycling in the cold, and cold-acclimated lux seedlings are sensitive to freezing stress. Our data show cold signaling is integrated into the clock by CBF-mediated regulation of LUX expression, thereby defining a new transcriptional mechanism for temperature input to the circadian clock.

  1. Arabidopsis MAP Kinase 4 regulates gene expression via transcription factor release in the nucleus

    DEFF Research Database (Denmark)

    Qiu, Jin-Long; Fiil, Berthe Katrine; Petersen, Klaus

    2008-01-01

    Plant and animal perception of microbes through pathogen surveillance proteins leads to MAP kinase signalling and the expression of defence genes. However, little is known about how plant MAP kinases regulate specific gene expression. We report that, in the absence of pathogens, Arabidopsis MAP...... supported by the suppression of PAD3 expression in mpk4-wrky33 double mutant backgrounds. Our data establish direct links between MPK4 and innate immunity and provide an example of how a plant MAP kinase can regulate gene expression by releasing transcription factors in the nucleus upon activation....

  2. Intronic T-DNA insertion in Arabidopsis NBR1 conditionally affects wild-type transcript level

    OpenAIRE

    Rodríguez, Milagros Collados; Wawrzyńska, Anna; Sirko, Agnieszka

    2014-01-01

    Abstract The SALK_135513 line of Arabidopsis thaliana is annotated by GenBank to have the T-DNA insertion in the fourth exon of NBR1 (At4g24690). Careful molecular analyses of the homozygous plants of SALK_135513 line indicated the place of T-DNA insertion in the fourth intron. Unexpectedly, 2 kinds of NBR1 transcripts, the wild-type and the mutated, resulting from alternative splicing events, were detected in those plants. Our findings explain the problems encountered by us with phenotypic e...

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

    DEFF Research Database (Denmark)

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

    2013-01-01

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

  4. Transcription factors that directly regulate the expression of CSLA9 encoding mannan synthase in Arabidopsis thaliana.

    Science.gov (United States)

    Kim, Won-Chan; Reca, Ida-Barbara; Kim, Yongsig; Park, Sunchung; Thomashow, Michael F; Keegstra, Kenneth; Han, Kyung-Hwan

    2014-03-01

    Mannans are hemicellulosic polysaccharides that have a structural role and serve as storage reserves during plant growth and development. Previous studies led to the conclusion that mannan synthase enzymes in several plant species are encoded by members of the cellulose synthase-like A (CSLA) gene family. Arabidopsis has nine members of the CSLA gene family. Earlier work has shown that CSLA9 is responsible for the majority of glucomannan synthesis in both primary and secondary cell walls of Arabidopsis inflorescence stems. Little is known about how expression of the CLSA9 gene is regulated. Sequence analysis of the CSLA9 promoter region revealed the presence of multiple copies of a cis-regulatory motif (M46RE) recognized by transcription factor MYB46, leading to the hypothesis that MYB46 (At5g12870) is a direct regulator of the mannan synthase CLSA9. We obtained several lines of experimental evidence in support of this hypothesis. First, the expression of CSLA9 was substantially upregulated by MYB46 overexpression. Second, electrophoretic mobility shift assay (EMSA) was used to demonstrate the direct binding of MYB46 to the promoter of CSLA9 in vitro. This interaction was further confirmed in vivo by a chromatin immunoprecipitation assay. Finally, over-expression of MYB46 resulted in a significant increase in mannan content. Considering the multifaceted nature of MYB46-mediated transcriptional regulation of secondary wall biosynthesis, we reasoned that additional transcription factors are involved in the CSLA9 regulation. This hypothesis was tested by carrying out yeast-one hybrid screening, which identified ANAC041 and bZIP1 as direct regulators of CSLA9. Transcriptional activation assays and EMSA were used to confirm the yeast-one hybrid results. Taken together, we report that transcription factors ANAC041, bZIP1 and MYB46 directly regulate the expression of CSLA9.

  5. Employing libraries of zinc finger artificial transcription factors to screen for homologous recombination mutants in Arabidopsis.

    Science.gov (United States)

    Lindhout, Beatrice I; Pinas, Johan E; Hooykaas, Paul J J; van der Zaal, Bert J

    2006-11-01

    A library of genes for zinc finger artificial transcription factors (ZF-ATF) was generated by fusion of DNA sequences encoding three-finger Cys(2)His(2) ZF domains to the VP16 activation domain under the control of the promoter of the ribosomal protein gene RPS5A from Arabidopsis thaliana. After introduction of this library into an Arabidopsis homologous recombination (HR) indicator line, we selected primary transformants exhibiting multiple somatic recombination events. After PCR-mediated rescue of ZF sequences, reconstituted ZF-ATFs were re-introduced in the target line. In this manner, a ZF-ATF was identified that led to a 200-1000-fold increase in somatic HR (replicated in an independent second target line). A mutant plant line expressing the HR-inducing ZF-ATF exhibited increased resistance to the DNA-damaging agent bleomycin and was more sensitive to methyl methanesulfonate (MMS), a combination of traits not described previously. Our results demonstrate that the use of ZF-ATF pools is highly rewarding when screening for novel dominant phenotypes in Arabidopsis.

  6. Transcription factor families in Arabidopsis: major progress and outstanding issues for future research.

    Science.gov (United States)

    Qu, Li-Jia; Zhu, Yu-Xian

    2006-10-01

    Transcription factors (TFs) are a group of proteins that control cellular processes by regulating the expression of downstream target genes. Recent progress has been made in the cloning and characterization of Arabidopsis TFs on the genome scale, especially on the cloning of open reading frames (ORFs), sequence analysis and the expression profiling of different TF families. Huge difference in numbers of subfamily members were found for Arabidopsis MYB, C2H2 (Zn), C3H-type 1 (Zn), C3H-type 2 (Zn) TFs by independent research groups, mainly because of differences in bioinformatic search stringency. However, the Arabidopsis and rice genomes contain very different numbers of TFs in the WRKY, NAC, bZIP, MADS, ALFIN-like, GRAS and C2C2 (Zn)-dof families, indicating a possible divergence of biological functions from dicots to monocots. TFs have also been found to play key roles in the biosynthesis and signaling of plant hormones, in cell growth and differentiation, and in photomorphogenesis.

  7. Calmodulin-binding transcription activator (CAMTA) 3 mediates biotic defense responses in Arabidopsis.

    Science.gov (United States)

    Galon, Yael; Nave, Roy; Boyce, Joy M; Nachmias, Dikla; Knight, Marc R; Fromm, Hillel

    2008-03-19

    Calmodulin-binding transcription activator (CAMTA) 3 (also called SR1) is a calmodulin-binding transcription factor in Arabidopsis. Two homozygous T-DNA insertion mutants (camta3-1, camta3-2) showed enhanced spontaneous lesions. Transcriptome analysis of both mutants revealed 6 genes with attenuated expression and 99 genes with elevated expression. Of the latter, 32 genes are related to defense against pathogens (e.g. WRKY33, PR1 and chitinase). Propagation of a virulent strain of the bacterial pathogen Pseudomonas syringae and the fungal pathogen Botrytis cinerea were attenuated in both mutants. Moreover, both mutants accumulated high levels of H2O2. We suggest that CAMTA3 regulates the expression of a set of genes involved in biotic defense responses.

  8. Gibberellic acid and cGMP-dependent transcriptional regulation in arabidopsis thaliana

    KAUST Repository

    Bastian, René

    2010-03-01

    An ever increasing amount of transcriptomic data and analysis tools provide novel insight into complex responses of biological systems. Given these resources we have undertaken to review aspects of transcriptional regulation in response to the plant hormone gibberellic acid (GA) and its second messenger guanosine 3\\',5\\'-cyclic monophosphate (cGMP) in Arabidopsis thaliana, both wild type and selected mutants. Evidence suggests enrichment of GA-responsive (GARE) elements in promoters of genes that are transcriptionally upregulated in response to cGMP but downregulated in a GA insensitive mutant (ga1-3). In contrast, in the genes upregulated in the mutant, no enrichment in the GARE is observed suggesting that GARE motifs are diagnostic for GA-induced and cGMP-dependent transcriptional upregulation. Further, we review how expression studies of GA-dependent transcription factors and transcriptional networks based on common promoter signatures derived from ab initio analyses can contribute to our understanding of plant responses at the systems level. © 2010 Landes Bioscience.

  9. Regulation of CAPRICE transcription by MYB proteins for root epidermis differentiation in Arabidopsis.

    Science.gov (United States)

    Koshino-Kimura, Yoshihiro; Wada, Takuji; Tachibana, Tatsuhiko; Tsugeki, Ryuji; Ishiguro, Sumie; Okada, Kiyotaka

    2005-06-01

    Epidermal cell differentiation in Arabidopsis root is studied as a model system for understanding cell fate specification. Two types of MYB-related transcription factors are involved in this cell differentiation. One of these, CAPRICE (CPC), encoding an R3-type MYB protein, is a positive regulator of hair cell differentiation and is preferentially transcribed in hairless cells. We analyzed the regulatory mechanism of CPC transcription. Deletion analyses of the CPC promoter revealed that hairless cell-specific transcription of the CPC gene required a 69 bp sequence, and a tandem repeat of this region was sufficient for its expression in epidermis. This region includes two MYB-binding sites, and the epidermis-specific transcription of CPC was abolished when base substitutions were introduced in these sites. We showed by gel mobility shift experiments and by yeast one-hybrid assay that WEREWOLF (WER), which is an R2R3-type MYB protein, directly binds to this region. We showed that WER also binds to the GL2 promoter region, indicating that WER directly regulates CPC and GL2 transcription by binding to their promoter regions.

  10. Regulation of WRKY46 transcription factor function by mitogen-activated protein kinases in Arabidopsis thaliana.

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    Arsheed Hussain Sheikh

    2016-02-01

    Full Text Available AbstractMitogen-activated protein kinase (MAPK cascades are central signalling pathways activated in plants after sensing internal developmental and external stress cues. Knowledge about the downstream substrate proteins of MAPKs is still limited in plants. We screened Arabidopsis WRKY transcription factors as potential targets downstream of MAPKs, and concentrated on characterizing WRKY46 as a substrate of the MAPK, MPK3. Mass spectrometry revealed in vitro phosphorylation of WRKY46 at amino acid position S168 by MPK3. However, mutagenesis studies showed that a second phosphosite, S250, can also be phosphorylated. Elicitation with pathogen-associated molecular patterns (PAMPs, such as the bacterial flagellin-derived flg22 peptide led to in vivo destabilization of WRKY46 in Arabidopsis protoplasts. Mutation of either phosphorylation site reduced the PAMP-induced degradation of WRKY46. Furthermore, the protein for the double phosphosite mutant is expressed at higher levels compared to wild-type proteins or single phosphosite mutants. In line with its nuclear localization and predicted function as a transcriptional activator, overexpression of WRKY46 in protoplasts raised basal plant defence as reflected by the increase in promoter activity of the PAMP-responsive gene, NHL10, in a MAPK-dependent manner. Thus, MAPK-mediated regulation of WRKY46 is a mechanism to control plant defence.

  11. LATERAL ORGAN BOUNDARIES DOMAIN transcription factors direct callus formation in Arabidopsis regeneration

    Institute of Scientific and Technical Information of China (English)

    Mingzhu Fan; Chongyi Xu; Ke Xu; Yuxin Hu

    2012-01-01

    The remarkable regeneration capability of plant tissues or organs under culture conditions has underlain an extensive practice for decades.The initial step in plant in vitro regeneration often involves the induction of a pluripotent cell mass termed callus,which is driven by the phytohormone auxin and occurs via a root development pathway.However,the key molecules governing callus formation remain unknown.Here we demonstrate that Arabidopsis LATERAL ORGAN BOUNDARIES DOMAIN (LBD)/ASYMMETRIC LEAVES2-LIKE (ASL) transcription factors are involved in the control of callus formation program.The four LBD genes downstream of AUXIN RESPONSE FACTORs (ARFs),LBD16,LBD17,LBD18 and LBD29,are rapidly and dramatically induced by callus-inducing medium (CIM) in multiple organs.Ectopic expression of each of the four LBD genes in Arabidopsis is sufficient to trigger spontaneous callus formation without exogenous phytohormones,whereas suppression of LBD function inhibits the callus formation induced by CIM.Moreover,the callus triggered by LBD resembles that induced by CIM by characteristics of ectopically activated root meristem genes and efficient regeneration capacity.These findings define LBD transcription factors as key regulators in the callus induction process,thereby establishing a molecular link between auxin signaling and the plant regeneration program.

  12. Differential contribution of transcription factors to Arabidopsis thaliana defence against Spodoptera littoralis.

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    Fabian eSchweizer

    2013-02-01

    Full Text Available In response to insect herbivory, Arabidopsis plants activate the synthesis of the phytohormone jasmonate-isoleucine (JA-Ile, which binds to a complex consisting of the receptor COI1 and JAZ repressors. Upon proteasome-mediated JAZ degradation, basic helix-loop-helix transcription factors (TFs MYC2, MYC3, and MYC4 become activated and this results in the expression of defence genes. Although the jasmonate (JA pathway is known to be essential for the massive transcriptional reprogramming that follows herbivory, there is however little information on other TFs that are required for defence against herbivores and whether they contribute significantly to JA-dependent defence gene expression. By transcriptome profiling, we identified 41 TFs that were induced in response to herbivory by the generalist Spodoptera littoralis. Among them, nine genes, including WRKY18, WRKY40, ANAC019, ANAC055, ZAT10, ZAT12, AZF2, ERF13, and RRTF1, were found to play a significant role in resistance to S. littoralis herbivory. However, compared to the triple mutant myc234 that is as sensitive as coi1-1 to herbivory, knockout lines of these nine TFs were only partially more sensitive to S. littoralis and showed only minor gene expression changes at the whole genome level. Data thus reveal that MYC2, MYC3, and MYC4 are master regulators of Arabidopsis resistance to a generalist herbivore and identify new genes involved in insect defence.

  13. Two Arabidopsis orthologs of the transcriptional coactivator ADA2 have distinct biological functions.

    Science.gov (United States)

    Hark, Amy T; Vlachonasios, Konstantinos E; Pavangadkar, Kanchan A; Rao, Sumana; Gordon, Hillary; Adamakis, Ioannis-Dimosthenis; Kaldis, Athanasios; Thomashow, Michael F; Triezenberg, Steven J

    2009-02-01

    Histone acetylation is an example of covalent modification of chromatin structure that has the potential to regulate gene expression. Gcn5 is a prototypical histone acetyltransferase that associates with the transcriptional coactivator Ada2. In Arabidopsis, two genes encode proteins that resemble yeast ADA2 and share approximately 45% amino acid sequence identity. We previously reported that plants harboring a T-DNA insertion in the ADA2b gene display a dwarf phenotype with developmental defects in several organs. Here we describe T-DNA insertion alleles in the ADA2a gene, which result in no dramatic growth or developmental phenotype. Both ADA2a and ADA2b are expressed in a variety of plant tissues; moreover, expression of ADA2a from a constitutive promoter fails to complement the ada2b-1 mutant phenotype, consistent with the hypothesis that the two proteins have distinct biochemical roles. To further probe the cellular roles of ADA2a and ADA2b, we studied the response of the transcriptional coactivator mutants to abiotic stress. Although ada2b seedlings display hypersensitivity to salt and abscisic acid and altered responses to low temperature stress, the responses of ada2a seedlings to abiotic stress generally parallel those of wildtype plants. Intriguingly, ada2a;ada2b double mutant plants display an intermediate, gcn5-like phenotype, suggesting that ADA2a and ADA2b each work independently with GCN5 to affect genome function in Arabidopsis.

  14. The transcription factor WIN1/SHN1 regulates Cutin biosynthesis in Arabidopsis thaliana.

    Science.gov (United States)

    Kannangara, Rubini; Branigan, Caroline; Liu, Yan; Penfield, Teresa; Rao, Vijaya; Mouille, Grégory; Höfte, Herman; Pauly, Markus; Riechmann, José Luis; Broun, Pierre

    2007-04-01

    The composition and permeability of the cuticle has a large influence on its ability to protect the plant against various forms of biotic and abiotic stress. WAX INDUCER1 (WIN1) and related transcription factors have recently been shown to trigger wax production, enhance drought tolerance, and modulate cuticular permeability when overexpressed in Arabidopsis thaliana. We found that WIN1 influences the composition of cutin, a polyester that forms the backbone of the cuticle. WIN1 overexpression induces compositional changes and an overall increase in cutin production in vegetative and reproductive organs, while its downregulation has the opposite effect. Changes in cutin composition are preceded by the rapid and coordinated induction of several genes known or likely to be involved in cutin biosynthesis. This transcriptional response is followed after a delay by the induction of genes associated with wax biosynthesis, suggesting that the regulation of cutin and wax production by WIN1 is a two-step process. We demonstrate that at least one of the cutin pathway genes, which encodes long-chain acyl-CoA synthetase LACS2, is likely to be directly targeted by WIN1. Overall, our results suggest that WIN1 modulates cuticle permeability in Arabidopsis by regulating genes encoding cutin pathway enzymes.

  15. Deciphering transcriptional and metabolic networks associated with lysine metabolism during Arabidopsis seed development.

    Science.gov (United States)

    Angelovici, Ruthie; Fait, Aaron; Zhu, Xiaohong; Szymanski, Jedrzej; Feldmesser, Ester; Fernie, Alisdair R; Galili, Gad

    2009-12-01

    In order to elucidate transcriptional and metabolic networks associated with lysine (Lys) metabolism, we utilized developing Arabidopsis (Arabidopsis thaliana) seeds as a system in which Lys synthesis could be stimulated developmentally without application of chemicals and coupled this to a T-DNA insertion knockout mutation impaired in Lys catabolism. This seed-specific metabolic perturbation stimulated Lys accumulation starting from the initiation of storage reserve accumulation. Our results revealed that the response of seed metabolism to the inducible alteration of Lys metabolism was relatively minor; however, that which was observable operated in a modular manner. They also demonstrated that Lys metabolism is strongly associated with the operation of the tricarboxylic acid cycle while largely disconnected from other metabolic networks. In contrast, the inducible alteration of Lys metabolism was strongly associated with gene networks, stimulating the expression of hundreds of genes controlling anabolic processes that are associated with plant performance and vigor while suppressing a small number of genes associated with plant stress interactions. The most pronounced effect of the developmentally inducible alteration of Lys metabolism was an induction of expression of a large set of genes encoding ribosomal proteins as well as genes encoding translation initiation and elongation factors, all of which are associated with protein synthesis. With respect to metabolic regulation, the inducible alteration of Lys metabolism was primarily associated with altered expression of genes belonging to networks of amino acids and sugar metabolism. The combined data are discussed within the context of network interactions both between and within metabolic and transcriptional control systems.

  16. DELLA-induced early transcriptional changes during etiolated development in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Javier Gallego-Bartolomé

    Full Text Available The hormones gibberellins (GAs control a wide variety of processes in plants, including stress and developmental responses. This task largely relies on the activity of the DELLA proteins, nuclear-localized transcriptional regulators that do not seem to have DNA binding capacity. The identification of early target genes of DELLA action is key not only to understand how GAs regulate physiological responses, but also to get clues about the molecular mechanisms by which DELLAs regulate gene expression. Here, we have investigated the global, early transcriptional response triggered by the Arabidopsis DELLA protein GAI during skotomorphogenesis, a developmental program tightly regulated by GAs. Our results show that the induction of GAI activity has an almost immediate effect on gene expression. Although this transcriptional regulation is largely mediated by the PIFs and HY5 transcription factors based on target meta-analysis, additional evidence points to other transcription factors that would be directly involved in DELLA regulation of gene expression. First, we have identified cis elements recognized by Dofs and type-B ARRs among the sequences enriched in the promoters of GAI targets; and second, an enrichment in additional cis elements appeared when this analysis was extended to a dataset of early targets of the DELLA protein RGA: CArG boxes, bound by MADS-box proteins, and the E-box CACATG that links the activity of DELLAs to circadian transcriptional regulation. Finally, Gene Ontology analysis highlights the impact of DELLA regulation upon the homeostasis of the GA, auxin, and ethylene pathways, as well as upon pre-existing transcriptional networks.

  17. A Protein Complex Required for Polymerase V Transcripts and RNA- Directed DNA Methylation in Arabidopsis

    KAUST Repository

    Law, Julie A.

    2010-05-01

    DNA methylation is an epigenetic modification associated with gene silencing. In Arabidopsis, DNA methylation is established by DOMAINS REARRANGED METHYLTRANSFERASE 2 (DRM2), which is targeted by small interfering RNAs through a pathway termed RNA-directed DNA methylation (RdDM) [1, 2]. Recently, RdDM was shown to require intergenic noncoding (IGN) transcripts that are dependent on the Pol V polymerase. These transcripts are proposed to function as scaffolds for the recruitment of downstream RdDM proteins, including DRM2, to loci that produce both siRNAs and IGN transcripts [3]. However, the mechanism(s) through which Pol V is targeted to specific genomic loci remains largely unknown. Through affinity purification of two known RdDM components, DEFECTIVE IN RNA-DIRECTED DNA METHYLATION 1 (DRD1) [4] and DEFECTIVE IN MERISTEM SILENCING 3 (DMS3) [5, 6], we found that they copurify with each other and with a novel protein, RNA-DIRECTED DNA METHYLATION 1 (RDM1), forming a complex we term DDR. We also found that DRD1 copurified with Pol V subunits and that RDM1, like DRD1 [3] and DMS3 [7], is required for the production of Pol V-dependent transcripts. These results suggest that the DDR complex acts in RdDM at a step upstream of the recruitment or activation of Pol V. © 2010 Elsevier Ltd. All rights reserved.

  18. A trihelix DNA binding protein counterbalances hypoxia-responsive transcriptional activation in Arabidopsis.

    Science.gov (United States)

    Giuntoli, Beatrice; Lee, Seung Cho; Licausi, Francesco; Kosmacz, Monika; Oosumi, Teruko; van Dongen, Joost T; Bailey-Serres, Julia; Perata, Pierdomenico

    2014-09-01

    Transcriptional activation in response to hypoxia in plants is orchestrated by ethylene-responsive factor group VII (ERF-VII) transcription factors, which are stable during hypoxia but destabilized during normoxia through their targeting to the N-end rule pathway of selective proteolysis. Whereas the conditionally expressed ERF-VII genes enable effective flooding survival strategies in rice, the constitutive accumulation of N-end-rule-insensitive versions of the Arabidopsis thaliana ERF-VII factor RAP2.12 is maladaptive. This suggests that transcriptional activation under hypoxia that leads to anaerobic metabolism may need to be fine-tuned. However, it is presently unknown whether a counterbalance of RAP2.12 exists. Genome-wide transcriptome analyses identified an uncharacterized trihelix transcription factor gene, which we named HYPOXIA RESPONSE ATTENUATOR1 (HRA1), as highly up-regulated by hypoxia. HRA1 counteracts the induction of core low oxygen-responsive genes and transcriptional activation of hypoxia-responsive promoters by RAP2.12. By yeast-two-hybrid assays and chromatin immunoprecipitation we demonstrated that HRA1 interacts with the RAP2.12 protein but with only a few genomic DNA regions from hypoxia-regulated genes, indicating that HRA1 modulates RAP2.12 through protein-protein interaction. Comparison of the low oxygen response of tissues characterized by different levels of metabolic hypoxia (i.e., the shoot apical zone versus mature rosette leaves) revealed that the antagonistic interplay between RAP2.12 and HRA1 enables a flexible response to fluctuating hypoxia and is of importance to stress survival. In Arabidopsis, an effective low oxygen-sensing response requires RAP2.12 stabilization followed by HRA1 induction to modulate the extent of the anaerobic response by negative feedback regulation of RAP2.12. This mechanism is crucial for plant survival under suboptimal oxygenation conditions. The discovery of the feedback loop regulating the oxygen

  19. Repression of Seed Maturation Genes by a Trihelix Transcriptional Repressor in Arabidopsis Seedlings[W

    Science.gov (United States)

    Gao, Ming-Jun; Lydiate, Derek J.; Li, Xiang; Lui, Helen; Gjetvaj, Branimir; Hegedus, Dwayne D.; Rozwadowski, Kevin

    2009-01-01

    The seed maturation program is repressed during germination and seedling development so that embryonic genes are not expressed in vegetative organs. Here, we describe a regulator that represses the expression of embryonic seed maturation genes in vegetative tissues. ASIL1 (for Arabidopsis 6b-interacting protein 1-like 1) was isolated by its interaction with the Arabidopsis thaliana 2S3 promoter. ASIL1 possesses domains conserved in the plant-specific trihelix family of DNA binding proteins and belongs to a subfamily of 6b-interacting protein 1-like factors. The seedlings of asil1 mutants exhibited a global shift in gene expression to a profile resembling late embryogenesis. LEAFY COTYLEDON1 and 2 were markedly derepressed during early germination, as was a large subset of seed maturation genes, such as those encoding seed storage proteins and oleosins, in seedlings of asil1 mutants. Consistent with this, asil1 seedlings accumulated 2S albumin and oil with a fatty acid composition similar to that of seed-derived lipid. Moreover, ASIL1 specifically recognized a GT element that overlaps the G-box and is in close proximity to the RY repeats of the 2S promoters. We suggest that ASIL1 targets GT-box–containing embryonic genes by competing with the binding of transcriptional activators to this promoter region. PMID:19155348

  20. Fusarium oxysporum triggers tissue-specific transcriptional reprogramming in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Rebecca Lyons

    Full Text Available Some of the most devastating agricultural diseases are caused by root-infecting pathogens, yet the majority of studies on these interactions to date have focused on the host responses of aerial tissues rather than those belowground. Fusarium oxysporum is a root-infecting pathogen that causes wilt disease on several plant species including Arabidopsis thaliana. To investigate and compare transcriptional changes triggered by F. oxysporum in different Arabidopsis tissues, we infected soil-grown plants with F. oxysporum and subjected root and leaf tissue harvested at early and late timepoints to RNA-seq analyses. At least half of the genes induced or repressed by F. oxysporum showed tissue-specific regulation. Regulators of auxin and ABA signalling, mannose binding lectins and peroxidases showed strong differential expression in root tissue. We demonstrate that ARF2 and PRX33, two genes regulated in the roots, promote susceptibility to F. oxysporum. In the leaves, defensins and genes associated with the response to auxin, cold and senescence were strongly regulated while jasmonate biosynthesis and signalling genes were induced throughout the plant.

  1. DEWAX-mediated transcriptional repression of cuticular wax biosynthesis in Arabidopsis thaliana.

    Science.gov (United States)

    Suh, Mi Chung; Go, Young Sam

    2014-06-06

    The aerial parts of plants are covered with a cuticular wax layer, which is the first barrier between a plant and its environment. Although cuticular wax deposition increases more in the light than in the dark, little is known about the molecular mechanisms underlying the regulation of cuticular wax biosynthesis. Recently DEWAX (Decrease Wax Biosynthesis) encoding an AP2/ERF transcription factor was found to be preferentially expressed in the epidermis and induced by darkness. Wax analysis of the dewax knockout mutant, wild type, and DEWAX overexpression lines (OX) indicates that DEWAX is a negative regulator of cuticular wax biosynthesis. DEWAX represses the expression of wax biosynthetic genes CER1, LACS2, ACLA2, and ECR via direct interaction with their promoters. Cuticular wax biosynthesis is negatively regulated twice a day by the expression of DEWAX; throughout the night and another for stomata closing. Taken together, it is evident that DEWAX-mediated negative regulation of the wax biosynthetic genes plays role in determining the total wax loads produced in Arabidopsis during daily dark and light cycles. In addition, significantly higher levels of DEWAX transcripts in leaves than stems suggest that DEWAX-mediated transcriptional repression might be involved in the organ-specific regulation of total wax amounts on plant surfaces.

  2. Inference of transcriptional networks in Arabidopsis through conserved noncoding sequence analysis.

    Science.gov (United States)

    Van de Velde, Jan; Heyndrickx, Ken S; Vandepoele, Klaas

    2014-07-01

    Transcriptional regulation plays an important role in establishing gene expression profiles during development or in response to (a)biotic stimuli. Transcription factor binding sites (TFBSs) are the functional elements that determine transcriptional activity, and the identification of individual TFBS in genome sequences is a major goal to inferring regulatory networks. We have developed a phylogenetic footprinting approach for the identification of conserved noncoding sequences (CNSs) across 12 dicot plants. Whereas both alignment and non-alignment-based techniques were applied to identify functional motifs in a multispecies context, our method accounts for incomplete motif conservation as well as high sequence divergence between related species. We identified 69,361 footprints associated with 17,895 genes. Through the integration of known TFBS obtained from the literature and experimental studies, we used the CNSs to compile a gene regulatory network in Arabidopsis thaliana containing 40,758 interactions, of which two-thirds act through binding events located in DNase I hypersensitive sites. This network shows significant enrichment toward in vivo targets of known regulators, and its overall quality was confirmed using five different biological validation metrics. Finally, through the integration of detailed expression and function information, we demonstrate how static CNSs can be converted into condition-dependent regulatory networks, offering opportunities for regulatory gene annotation.

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

    Directory of Open Access Journals (Sweden)

    Li Maofu

    2016-01-01

    Full Text Available Flowering time is usually regulated by many environmental factors and endogenous signals. TGA family members are bZIP transcription factors that bind to the octopine synthase element, which has been closely linked to defense/stress responses. Most TGA factors interact with non-expressor of PR1 (NPR1 and plant defense responses are strengthened by this interaction. TGA1and TGA4factors bind to NPR1 only in salicylic acid (SA-induced leaves, suggesting that TGA4 has another function during plant development. Here, we isolated a bZIP transcription factor gene, TGA4, from Capsella rubella. TGA4transcripts were detected in most tissues, with high expression in leaves, low expression in stems and flowering buds, and undetectable in siliques. CruTGA4was over expressed in Arabidopsis thaliana wild typeCol-0 plants. Flowering time and total leaf number in the transgenic plants showed that overexpression of CruTGA4could delay flowering in A. thaliana. Our findings suggest that TGA4 may act as flowering regulator that controls plant flowering.

  4. Arabidopsis WRKY33 transcription factor is required for resistance to necrotrophic fungal pathogens.

    Science.gov (United States)

    Zheng, Zuyu; Qamar, Synan Abu; Chen, Zhixiang; Mengiste, Tesfaye

    2006-11-01

    Plant WRKY transcription factors are key regulatory components of plant responses to microbial infection. In addition to regulating the expression of defense-related genes, WRKY transcription factors have also been shown to regulate cross-talk between jasmonate- and salicylate-regulated disease response pathways. The two pathways mediate resistance against different types of microbial pathogens, and there are numerous reports of antagonistic interactions between them. Here we show that mutations of the Arabidopsis WRKY33 gene encoding a WRKY transcription factor cause enhanced susceptibility to the necrotrophic fungal pathogens Botrytis cinerea and Alternaria brassicicola concomitant with reduced expression of the jasmonate-regulated plant defensin PDF1.2 gene. Ectopic over-expression of WRKY33, on the other hand, increases resistance to the two necrotrophic fungal pathogens. The wrky33 mutants do not show altered responses to a virulent strain of the bacterial pathogen Pseudomonas syringae, although the ectopic expression of WRKY33 results in enhanced susceptibility to this pathogen. The susceptibility of WRKY33-over-expressing plants to P. syringae is associated with reduced expression of the salicylate-regulated PR-1 gene. The WRKY33 transcript is induced in response to pathogen infection, or treatment with salicylate or the paraquat herbicide that generates activated oxygen species in exposed cells. WRKY33 is localized to the nucleus of plant cells and recognizes DNA molecules containing the TTGACC W-box sequence. Together, these results indicate that pathogen-induced WRKY33 is an important transcription factor that regulates the antagonistic relationship between defense pathways mediating responses to P. syringae and necrotrophic pathogens.

  5. Regulatory Network of Transcription Factors in Response to Drought in Arabidopsis and Crops

    Institute of Scientific and Technical Information of China (English)

    Chen Li-miao; Li Wen-bin; Zhou Xin-an

    2012-01-01

    Drought is one of the most important environmental constraints limiting plant growth, development and crop yield. Many drought-inducible genes have been identified by molecular and genomic analyses in Arabidopsis, rice and other crops. To better understand reaction mechanism of plant to drought tolerance, we mainly focused on introducing the research of transcription factors (TFs) in signal transduction and regulatory network of gene expression conferring drought. A TF could bind multiple target genes to increase one or more kinds of stress tolerance. Sometimes, several TFs might act together with a target gene. So drought-tolerance genes or TFs might respond to high-salinity, cold or other stresses. The crosstalk of multiple stresses signal pathways is a crucial aspect of understanding stress signaling.

  6. Differential control of seed primary dormancy in Arabidopsis ecotypes by the transcription factor SPATULA.

    Science.gov (United States)

    Vaistij, Fabián E; Gan, Yinbo; Penfield, Steven; Gilday, Alison D; Dave, Anuja; He, Zhesi; Josse, Eve-Marie; Choi, Giltsu; Halliday, Karen J; Graham, Ian A

    2013-06-25

    Freshly matured seeds exhibit primary dormancy, which prevents germination until environmental conditions are favorable. The establishment of dormancy occurs during seed development and involves both genetic and environmental factors that impact on the ratio of two antagonistic phytohormones: abscisic acid (ABA), which promotes dormancy, and gibberellic acid, which promotes germination. Although our understanding of dormancy breakage in mature seeds is well advanced, relatively little is known about the mechanisms involved in establishing dormancy during seed maturation. We previously showed that the SPATULA (SPT) transcription factor plays a key role in regulating seed germination. Here we investigate its role during seed development and find that, surprisingly, it has opposite roles in setting dormancy in Landsberg erecta and Columbia Arabidopsis ecotypes. We also find that SPT regulates expression of five transcription factor encoding genes: ABA-INSENSITIVE4 (ABI4) and ABI5, which mediate ABA signaling; REPRESSOR-OF-GA (RGA) and RGA-LIKE3 involved in gibberellic acid signaling; and MOTHER-OF-FT-AND-TFL1 (MFT) that we show here promotes Arabidopsis seed dormancy. Although ABI4, RGA, and MFT are repressed by SPT, ABI5 and RGL3 are induced. Furthermore, we show that RGA, MFT, and ABI5 are direct targets of SPT in vivo. We present a model in which SPT drives two antagonistic "dormancy-repressing" and "dormancy-promoting" routes that operate simultaneously in freshly matured seeds. Each of these routes has different impacts and this in turn explains the opposite effect of SPT on seed dormancy of the two ecotypes analyzed here.

  7. Tissue-specific expression patterns of Arabidopsis NF-Y transcription factors suggest potential for extensive combinatorial complexity.

    Science.gov (United States)

    Siefers, Nicholas; Dang, Kristen K; Kumimoto, Roderick W; Bynum, William Edwards; Tayrose, Gregory; Holt, Ben F

    2009-02-01

    All aspects of plant and animal development are controlled by complex networks of transcription factors. Transcription factors are essential for converting signaling inputs, such as changes in daylength, into complex gene regulatory outputs. While some transcription factors control gene expression by binding to cis-regulatory elements as individual subunits, others function in a combinatorial fashion. How individual subunits of combinatorial transcription factors are spatially and temporally deployed (e.g. expression-level, posttranslational modifications and subcellular localization) has profound effects on their control of gene expression. In the model plant Arabidopsis (Arabidopsis thaliana), we have identified 36 Nuclear Factor Y (NF-Y) transcription factor subunits (10 NF-YA, 13 NF-YB, and 13 NF-YC subunits) that can theoretically combine to form 1,690 unique complexes. Individual plant subunits have functions in flowering time, embryo maturation, and meristem development, but how they combine to control these processes is unknown. To assist in the process of defining unique NF-Y complexes, we have created promoter:beta-glucuronidase fusion lines for all 36 Arabidopsis genes. Here, we show NF-Y expression patterns inferred from these promoter:beta-glucuronidase lines for roots, light- versus dark-grown seedlings, rosettes, and flowers. Additionally, we review the phylogenetic relationships and examine protein alignments for each NF-Y subunit family. The results are discussed with a special emphasis on potential roles for NF-Y subunits in photoperiod-controlled flowering time.

  8. Serine acts as a metabolic signal for the transcriptional control of photorespiration-related genes in Arabidopsis.

    Science.gov (United States)

    Timm, Stefan; Florian, Alexandra; Wittmiß, Maria; Jahnke, Kathrin; Hagemann, Martin; Fernie, Alisdair R; Bauwe, Hermann

    2013-05-01

    Photosynthetic carbon assimilation including photorespiration is dynamically regulated during the day/night cycle. This includes transcriptional regulation, such as the light induction of corresponding genes, but little is known about the contribution of photorespiratory metabolites to the regulation of gene expression. Here, we examined diurnal changes in the levels of photorespiratory metabolites, of enzymes of the photorespiratory carbon cycle, and of corresponding transcripts in wild-type plants of Arabidopsis (Arabidopsis thaliana) and in a mutant with altered photorespiratory flux due to the absence of the peroxisomal enzyme Hydroxypyruvate Reductase1 (HPR1). Metabolomics of the wild type showed that the relative amounts of most metabolites involved in photorespiration increased after the onset of light, exhibited maxima at the end of the day, and decreased during the night. In accordance with those findings, both the amounts of messenger RNAs encoding photorespiratory enzymes and the respective protein contents showed a comparable accumulation pattern. Deletion of HPR1 did not significantly alter most of the metabolite patterns relative to wild-type plants; only serine accumulated to a constitutively elevated amount in this mutant. In contrast, the hpr1 mutation resulted in considerable deregulation of the transcription of photorespiration-related genes. This transcriptional deregulation could also be induced by the external application of l-serine but not glycine to the Arabidopsis wild type, suggesting that serine acts as a metabolic signal for the transcriptional regulation of photorespiration, particularly in the glycine-to-serine interconversion reactions.

  9. Broad-spectrum acquired resistance in barley induced by the Pseudomonas pathosystem shares transcriptional components with Arabidopsis systemic acquired resistance.

    Science.gov (United States)

    Colebrook, E H; Creissen, G; McGrann, G R D; Dreos, R; Lamb, C; Boyd, L A

    2012-05-01

    Inducible resistance responses play a central role in the defense of plants against pathogen attack. Acquired resistance (AR) is induced alongside defense toward primary attack, providing broad-spectrum protection against subsequent pathogen challenge. The localization and molecular basis of AR in cereals is poorly understood, in contrast with the well-characterized systemic acquired resistance (SAR) response in Arabidopsis. Here, we use Pseudomonas syringae as a biological inducer of AR in barley, providing a clear frame of reference to the Arabidopsis-P. syringae pathosystem. Inoculation of barley leaf tissue with the nonadapted P. syringae pv. tomato avrRpm1 (PstavrRpm1) induced an active local defense response. Furthermore, inoculation of barley with PstavrRpm1 resulted in the induction of broad-spectrum AR at a distance from the local lesion, "adjacent" AR, effective against compatible isolates of P. syringae and Magnaporthe oryzae. Global transcriptional profiling of this adjacent AR revealed similarities with the transcriptional profile of SAR in Arabidopsis, as well as transcripts previously associated with chemically induced AR in cereals, suggesting that AR in barley and SAR in Arabidopsis may be mediated by analogous pathways.

  10. ATM-mediated transcriptional and developmental responses to gamma-rays in Arabidopsis.

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    Lilian Ricaud

    Full Text Available ATM (Ataxia Telangiectasia Mutated is an essential checkpoint kinase that signals DNA double-strand breaks in eukaryotes. Its depletion causes meiotic and somatic defects in Arabidopsis and progressive motor impairment accompanied by several cell deficiencies in patients with ataxia telangiectasia (AT. To obtain a comprehensive view of the ATM pathway in plants, we performed a time-course analysis of seedling responses by combining confocal laser scanning microscopy studies of root development and genome-wide expression profiling of wild-type (WT and homozygous ATM-deficient mutants challenged with a dose of gamma-rays (IR that is sublethal for WT plants. Early morphologic defects in meristematic stem cells indicated that AtATM, an Arabidopsis homolog of the human ATM gene, is essential for maintaining the quiescent center and controlling the differentiation of initial cells after exposure to IR. Results of several microarray experiments performed with whole seedlings and roots up to 5 h post-IR were compiled in a single table, which was used to import gene information and extract gene sets. Sequence and function homology searches; import of spatio-temporal, cell cycling, and mutant-constitutive expression characteristics; and a simplified functional classification system were used to identify novel genes in all functional classes. The hundreds of radiomodulated genes identified were not a random collection, but belonged to functional pathways such as those of the cell cycle; cell death and repair; DNA replication, repair, and recombination; and transcription; translation; and signaling, indicating the strong cell reprogramming and double-strand break abrogation functions of ATM checkpoints. Accordingly, genes in all functional classes were either down or up-regulated concomitantly with downregulation of chromatin deacetylases or upregulation of acetylases and methylases, respectively. Determining the early transcriptional indicators of

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

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    Iqbal M Javed

    2008-09-01

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

  12. DNA replication factor C1 mediates genomic stability and transcriptional gene silencing in Arabidopsis

    KAUST Repository

    Liu, Qian

    2010-07-01

    Genetic screening identified a suppressor of ros1-1, a mutant of REPRESSOR OF SILENCING1 (ROS1; encoding a DNA demethylation protein). The suppressor is a mutation in the gene encoding the largest subunit of replication factor C (RFC1). This mutation of RFC1 reactivates the unlinked 35S-NPTII transgene, which is silenced in ros1 and also increases expression of the pericentromeric Athila retrotransposons named transcriptional silent information in a DNA methylationindependent manner. rfc1 is more sensitive than the wild type to the DNA-damaging agent methylmethane sulphonate and to the DNA inter- and intra- cross-linking agent cisplatin. The rfc1 mutant constitutively expresses the G2/M-specific cyclin CycB1;1 and other DNA repair-related genes. Treatment with DNA-damaging agents mimics the rfc1 mutation in releasing the silenced 35S-NPTII, suggesting that spontaneously induced genomic instability caused by the rfc1 mutation might partially contribute to the released transcriptional gene silencing (TGS). The frequency of somatic homologous recombination is significantly increased in the rfc1 mutant. Interestingly, ros1 mutants show increased telomere length, but rfc1 mutants show decreased telomere length and reduced expression of telomerase. Our results suggest that RFC1 helps mediate genomic stability and TGS in Arabidopsis thaliana. © 2010 American Society of Plant Biologists.

  13. Arabidopsis MAP kinase 4 regulates gene expression through transcription factor release in the nucleus.

    Science.gov (United States)

    Qiu, Jin-Long; Fiil, Berthe Katrine; Petersen, Klaus; Nielsen, Henrik Bjørn; Botanga, Christopher J; Thorgrimsen, Stephan; Palma, Kristoffer; Suarez-Rodriguez, Maria Cristina; Sandbech-Clausen, Signe; Lichota, Jacek; Brodersen, Peter; Grasser, Klaus D; Mattsson, Ole; Glazebrook, Jane; Mundy, John; Petersen, Morten

    2008-08-20

    Plant and animal perception of microbes through pathogen surveillance proteins leads to MAP kinase signalling and the expression of defence genes. However, little is known about how plant MAP kinases regulate specific gene expression. We report that, in the absence of pathogens, Arabidopsis MAP kinase 4 (MPK4) exists in nuclear complexes with the WRKY33 transcription factor. This complex depends on the MPK4 substrate MKS1. Challenge with Pseudomonas syringae or flagellin leads to the activation of MPK4 and phosphorylation of MKS1. Subsequently, complexes with MKS1 and WRKY33 are released from MPK4, and WRKY33 targets the promoter of PHYTOALEXIN DEFICIENT3 (PAD3) encoding an enzyme required for the synthesis of antimicrobial camalexin. Hence, wrky33 mutants are impaired in the accumulation of PAD3 mRNA and camalexin production upon infection. That WRKY33 is an effector of MPK4 is further supported by the suppression of PAD3 expression in mpk4-wrky33 double mutant backgrounds. Our data establish direct links between MPK4 and innate immunity and provide an example of how a plant MAP kinase can regulate gene expression by releasing transcription factors in the nucleus upon activation.

  14. Soybean GmPHD-type transcription regulators improve stress tolerance in transgenic Arabidopsis plants.

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    Wei Wei

    Full Text Available BACKGROUND: Soybean [Glycine max (L. Merr.] is one of the most important crops for oil and protein resource. Improvement of stress tolerance will be beneficial for soybean seed production. PRINCIPAL FINDINGS: Six GmPHD genes encoding Alfin1-type PHD finger protein were identified and their expressions differentially responded to drought, salt, cold and ABA treatments. The six GmPHDs were nuclear proteins and showed ability to bind the cis-element "GTGGAG". The N-terminal domain of GmPHD played a major role in DNA binding. Using a protoplast assay system, we find that GmPHD1 to GmPHD5 had transcriptional suppression activity whereas GmPHD6 did not have. In yeast assay, the GmPHD6 can form homodimer and heterodimer with the other GmPHDs except GmPHD2. The N-terminal plus the variable regions but not the PHD-finger is required for the dimerization. Transgenic Arabidopsis plants overexpressing the GmPHD2 showed salt tolerance when compared with the wild type plants. This tolerance was likely achieved by diminishing the oxidative stress through regulation of downstream genes. SIGNIFICANCE: These results provide important clues for soybean stress tolerance through manipulation of PHD-type transcription regulator.

  15. β-amylase-like proteins function as transcription factors in Arabidopsis, controlling shoot growth and development.

    Science.gov (United States)

    Reinhold, Heike; Soyk, Sebastian; Simková, Klára; Hostettler, Carmen; Marafino, John; Mainiero, Samantha; Vaughan, Cara K; Monroe, Jonathan D; Zeeman, Samuel C

    2011-04-01

    Plants contain β-amylase-like proteins (BAMs; enzymes usually associated with starch breakdown) present in the nucleus rather than targeted to the chloroplast. They possess BRASSINAZOLE RESISTANT1 (BZR1)-type DNA binding domains--also found in transcription factors mediating brassinosteroid (BR) responses. The two Arabidopsis thaliana BZR1-BAM proteins (BAM7 and BAM8) bind a cis-regulatory element that both contains a G box and resembles a BR-responsive element. In protoplast transactivation assays, these BZR1-BAMs activate gene expression. Structural modeling suggests that the BAM domain's glucan binding cleft is intact, but the recombinant proteins are at least 1000 times less active than chloroplastic β-amylases. Deregulation of BZR1-BAMs (the bam7bam8 double mutant and BAM8-overexpressing plants) causes altered leaf growth and development. Of the genes upregulated in plants overexpressing BAM8 and downregulated in bam7bam8 plants, many carry the cis-regulatory element in their promoters. Many genes that respond to BRs are inversely regulated by BZR1-BAMs. We propose a role for BZR1-BAMs in controlling plant growth and development through crosstalk with BR signaling. Furthermore, we speculate that BZR1-BAMs may transmit metabolic signals by binding a ligand in their BAM domain, although diurnal changes in the concentration of maltose, a candidate ligand produced by chloroplastic β-amylases, do not influence their transcription factor function.

  16. Unraveling the WRKY transcription factors network in Arabidopsis Thaliana by integrative approach

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    Mouna Choura

    2015-06-01

    Full Text Available The WRKY transcription factors superfamily are involved in diverse biological processes in plants including response to biotic and abiotic stresses and plant immunity. Protein-protein interaction network is a useful approach for understanding these complex processes. The availability of Arabidopsis Thaliana interactome offers a good opportunity to do get a global view of protein network. In this work, we have constructed the WRKY transcription factor network by combining different sources of evidence and we characterized its topological features using computational tools. We found that WRKY network is a hub-based network involving multifunctional proteins denoted as hubs such as WRKY 70, WRKY40, WRKY 53, WRKY 60, WRKY 33 and WRKY 51. Functional annotation showed seven functional modules particularly involved in biotic stress and defense responses. Furthermore, the gene ontology and pathway enrichment analysis revealed that WRKY proteins are mainly involved in plant-pathogen interaction pathways and their functions are directly related to the stress response and immune system process.

  17. Isolation of transcription factor complexes from Arabidopsis cell suspension cultures by tandem affinity purification.

    Science.gov (United States)

    Van Leene, Jelle; Eeckhout, Dominique; Persiau, Geert; Van De Slijke, Eveline; Geerinck, Jan; Van Isterdael, Gert; Witters, Erwin; De Jaeger, Geert

    2011-01-01

    Defining protein complexes is critical to virtually all aspects of cell biology because most cellular processes are regulated by stable or more dynamic protein interactions. Elucidation of the protein-protein interaction network around transcription factors is essential to fully understand their function and regulation. In the last decade, new technologies have emerged to study protein-protein interactions under near-physiological conditions. We have developed a high-throughput tandem affinity purification (TAP)/mass spectrometry (MS) platform for cell suspension cultures to analyze protein complexes in Arabidopsis thaliana. This streamlined platform follows an integrated approach comprising generic Gateway-based vectors with high cloning flexibility, the fast generation of transgenic suspension cultures, TAP adapted for plant cells, and tandem matrix-assisted laser desorption ionization MS for the identification of purified proteins. Recently, we evaluated the GS tag, originally developed to study mammalian protein complexes, that combines two IgG-binding domains of protein G with a streptavidin-binding peptide, separated by two tobacco etch virus cleavage sites. We found that this GS tag outperforms the traditional TAP tag in plant cells, regarding both specificity and complex yield. Here, we provide detailed protocols of the GS-based TAP platform that allowed us to characterize transcription factor complexes involved in signaling in response to the plant phytohormone jasmonate.

  18. Regulation of Arabidopsis Early Anther Development by Putative Cell-Cell Signaling Molecules and Transcriptional Regulators

    Institute of Scientific and Technical Information of China (English)

    Yu-Jin Sun; Carey LH Hord; Chang-Bin Chen; Hong Ma

    2007-01-01

    Anther development in flowering plants involves the formation of several cell types, including the tapetal and pollen mother cells. The use of genetic and molecular tools has led to the identification and characterization of genes that are critical for normal cell division and differentiation in Arabidopsis early anther development. We review here several recent studies on these genes, including the demonstration that the putative receptor protein kinases BAM1 and BAM2 together play essential roles in the control of early cell division and differentiation. In addition, we discuss the hypothesis that BAM1/2 may form a positive-negative feedback regulatory loop with a previously identified key regulator, SPOROCYTELESS (also called NOZZLE),to control the balance between sporogenous and somatic cell types in the anther. Furthermore, we summarize the isolation and functional analysis of the DYSFUNCTIONAL TAPETUM1 (DYT1) gene in promoting proper tapetal cell differentiation. Our finding that DYT1 encodes a putative transcription factor of the bHLH family, as well as relevant expression analyses, strongly supports a model that DYT1 serves as a critical link between upstream factors and downstream target genes that are critical for normal tapetum development and function. These studies, together with other recently published works, indicate that cell-cell communication and transcriptional control are key processes essential for cell fate specification in anther development.

  19. The HIRA complex that deposits the histone H3.3 is conserved in Arabidopsis and facilitates transcriptional dynamics

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    Xin Nie

    2014-08-01

    Full Text Available In animals, replication-independent incorporation of nucleosomes containing the histone variant H3.3 enables global reprogramming of histone modifications and transcriptional profiles. H3.3 enrichment over gene bodies correlates with gene transcription in animals and plants. In animals, H3.3 is deposited into chromatin by specific protein complexes, including the HIRA complex. H3.3 variants evolved independently and acquired similar properties in animals and plants, questioning how the H3.3 deposition machinery evolved in plants and what are its biological functions. We performed phylogenetic analyses in the plant kingdom and identified in Arabidopsis all orthologs of human genes encoding members of the HIRA complex. Genetic analyses, biochemical data and protein localisation suggest that these proteins form a complex able to interact with H3.3 in Arabidopsis in a manner similar to that described in mammals. In contrast to animals, where HIRA is required for fertilization and early development, loss of function of HIRA in Arabidopsis causes mild phenotypes in the adult plant and does not perturb sexual reproduction and embryogenesis. Rather, HIRA function is required for transcriptional reprogramming during dedifferentiation of plant cells that precedes vegetative propagation and for the appropriate transcription of genes responsive to biotic and abiotic factors. We conclude that the molecular function of the HIRA complex is conserved between plants and animals. Yet plants diversified HIRA functions to enable asexual reproduction and responsiveness to the environment in response to the plant sessile lifestyle.

  20. The WEREWOLF MYB protein directly regulates CAPRICE transcription during cell fate specification in the Arabidopsis root epidermis.

    Science.gov (United States)

    Ryu, Kook Hui; Kang, Yeon Hee; Park, Young-hwan; Hwang, Ildoo; Schiefelbein, John; Lee, Myeong Min

    2005-11-01

    The Arabidopsis root epidermis is composed of two types of cells, hair cells and non-hair cells, and their fate is determined in a position-dependent manner. WEREWOLF (WER), a R2R3 MYB protein, has been shown genetically to function as a master regulator to control both of the epidermal cell fates. To directly test the proposed role of WER in this system, we examined its subcellular localization and defined its transcriptional activation properties. We show that a WER-GFP fusion protein is functional and accumulates in the nucleus of the N-position cells in the Arabidopsis root epidermis, as expected for a transcriptional regulator. We also find that a modified WER protein with a strong activation domain (WER-VP16) promotes the formation of both epidermal cell types, supporting the view that WER specifies both cell fates. In addition, we used the glucocorticoid receptor (GR) inducible system to show that CPC transcription is regulated directly by WER. Using EMSA, we found two WER-binding sites (WBSs; WBSI and WBSII) in the CPC promoter. WER-WBSI binding was confirmed in vivo using the yeast one-hybrid assay. Binding between the WER protein and both WBSs (WBSI and WBSII), and the importance of the two WBSs in CPC promoter activity were confirmed in Arabidopsis. These results provide experimental support for the proposed role of WER as an activator of gene transcription during the specification of both epidermal cell fates.

  1. CATMA, a comprehensive genome-scale resource for silencing and transcript profiling of Arabidopsis genes

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    Moreau Yves

    2007-10-01

    Full Text Available Abstract Background The Complete Arabidopsis Transcript MicroArray (CATMA initiative combines the efforts of laboratories in eight European countries 1 to deliver gene-specific sequence tags (GSTs for the Arabidopsis research community. The CATMA initiative offers the power and flexibility to regularly update the GST collection according to evolving knowledge about the gene repertoire. These GST amplicons can easily be reamplified and shared, subsets can be picked at will to print dedicated arrays, and the GSTs can be cloned and used for other functional studies. This ongoing initiative has already produced approximately 24,000 GSTs that have been made publicly available for spotted microarray printing and RNA interference. Results GSTs from the CATMA version 2 repertoire (CATMAv2, created in 2002 were mapped onto the gene models from two independent Arabidopsis nuclear genome annotation efforts, TIGR5 and PSB-EuGène, to consolidate a list of genes that were targeted by previously designed CATMA tags. A total of 9,027 gene models were not tagged by any amplified CATMAv2 GST, and 2,533 amplified GSTs were no longer predicted to tag an updated gene model. To validate the efficacy of GST mapping criteria and design rules, the predicted and experimentally observed hybridization characteristics associated to GST features were correlated in transcript profiling datasets obtained with the CATMAv2 microarray, confirming the reliability of this platform. To complete the CATMA repertoire, all 9,027 gene models for which no GST had yet been designed were processed with an adjusted version of the Specific Primer and Amplicon Design Software (SPADS. A total of 5,756 novel GSTs were designed and amplified by PCR from genomic DNA. Together with the pre-existing GST collection, this new addition constitutes the CATMAv3 repertoire. It comprises 30,343 unique amplified sequences that tag 24,202 and 23,009 protein-encoding nuclear gene models in the TAIR6 and Eu

  2. Structural and functional analysis of VQ motif-containing proteins in Arabidopsis as interacting proteins of WRKY transcription factors.

    Science.gov (United States)

    Cheng, Yuan; Zhou, Yuan; Yang, Yan; Chi, Ying-Jun; Zhou, Jie; Chen, Jian-Ye; Wang, Fei; Fan, Baofang; Shi, Kai; Zhou, Yan-Hong; Yu, Jing-Quan; Chen, Zhixiang

    2012-06-01

    WRKY transcription factors are encoded by a large gene superfamily with a broad range of roles in plants. Recently, several groups have reported that proteins containing a short VQ (FxxxVQxLTG) motif interact with WRKY proteins. We have recently discovered that two VQ proteins from Arabidopsis (Arabidopsis thaliana), SIGMA FACTOR-INTERACTING PROTEIN1 and SIGMA FACTOR-INTERACTING PROTEIN2, act as coactivators of WRKY33 in plant defense by specifically recognizing the C-terminal WRKY domain and stimulating the DNA-binding activity of WRKY33. In this study, we have analyzed the entire family of 34 structurally divergent VQ proteins from Arabidopsis. Yeast (Saccharomyces cerevisiae) two-hybrid assays showed that Arabidopsis VQ proteins interacted specifically with the C-terminal WRKY domains of group I and the sole WRKY domains of group IIc WRKY proteins. Using site-directed mutagenesis, we identified structural features of these two closely related groups of WRKY domains that are critical for interaction with VQ proteins. Quantitative reverse transcription polymerase chain reaction revealed that expression of a majority of Arabidopsis VQ genes was responsive to pathogen infection and salicylic acid treatment. Functional analysis using both knockout mutants and overexpression lines revealed strong phenotypes in growth, development, and susceptibility to pathogen infection. Altered phenotypes were substantially enhanced through cooverexpression of genes encoding interacting VQ and WRKY proteins. These findings indicate that VQ proteins play an important role in plant growth, development, and response to environmental conditions, most likely by acting as cofactors of group I and IIc WRKY transcription factors.

  3. Transcription factor veracity: is GBF3 responsible for ABA-regulated expression of Arabidopsis Adh?

    Science.gov (United States)

    Lu, G; Paul, A L; McCarty, D R; Ferl, R J

    1996-01-01

    Assignment of particular transcription factors to specific roles in promoter elements can be problematic, especially in systems such as the G-box, where multiple factors of overlapping specificity exist. In the Arabidopsis alcohol dehydrogenase (Adh) promoter, the G-box regulates expression in response to cold and dehydration, presumably through the action of abscisic acid (ABA), and is bound by a nuclear protein complex in vivo during expression in cell cultures. In this report, we test the conventional wisdom of biochemical approaches used to identify DNA binding proteins and assess their specific interactions by using the G-box and a nearby half G-box element of the Arabidopsis Adh promoter as a model system. Typical in vitro assays demonstrated specific interaction of G-box factor 3 (GBF3) with both the G-box and the half G-box element. Dimethyl sulfate footprint analysis confirmed that the in vitro binding signature of GBF3 essentially matches the footprint signature detected in vivo at the G-box. Because RNA gel blot data indicated that GBF3 is itself induced by ABA, we might have concluded that GBF3 is indeed the GBF responsible in cell cultures for binding to the Adh G-box and is therefore responsible for ABA-regulated expression of Adh. Potential limitations of this conclusion are exposed by the fact that other GBFs bind the G-box with the same signature as GBF3, and subtle differences between in vivo and in vitro footprint signatures indicate that factors other than or in addition to GBF3 interact with the half G-box element. PMID:8672884

  4. Photosynthesis of root chloroplasts developed in Arabidopsis lines overexpressing GOLDEN2-LIKE transcription factors.

    Science.gov (United States)

    Kobayashi, Koichi; Sasaki, Daichi; Noguchi, Ko; Fujinuma, Daiki; Komatsu, Hirohisa; Kobayashi, Masami; Sato, Mayuko; Toyooka, Kiminori; Sugimoto, Keiko; Niyogi, Krishna K; Wada, Hajime; Masuda, Tatsuru

    2013-08-01

    In plants, genes involved in photosynthesis are encoded separately in nuclei and plastids, and tight cooperation between these two genomes is therefore required for the development of functional chloroplasts. Golden2-like (GLK) transcription factors are involved in chloroplast development, directly targeting photosynthesis-associated nuclear genes for up-regulation. Although overexpression of GLKs leads to chloroplast development in non-photosynthetic organs, the mechanisms of coordination between the nuclear gene expression influenced by GLKs and the photosynthetic processes inside chloroplasts are largely unknown. To elucidate the impact of GLK-induced expression of photosynthesis-associated nuclear genes on the construction of photosynthetic systems, chloroplast morphology and photosynthetic characteristics in greenish roots of Arabidopsis thaliana lines overexpressing GLKs were compared with those in wild-type roots and leaves. Overexpression of GLKs caused up-regulation of not only their direct targets but also non-target nuclear and plastid genes, leading to global induction of chloroplast biogenesis in the root. Large antennae relative to reaction centers were observed in wild-type roots and were further enhanced by GLK overexpression due to the increased expression of target genes associated with peripheral light-harvesting antennae. Photochemical efficiency was lower in the root chloroplasts than in leaf chloroplasts, suggesting that the imbalance in the photosynthetic machinery decreases the efficiency of light utilization in root chloroplasts. Despite the low photochemical efficiency, root photosynthesis contributed to carbon assimilation in Arabidopsis. Moreover, GLK overexpression increased CO₂ fixation and promoted phototrophic performance of the root, showing the potential of root photosynthesis to improve effective carbon utilization in plants.

  5. Tomato Whole Genome Transcriptional Response to Tetranychus urticae Identifies Divergence of Spider Mite-Induced Responses Between Tomato and Arabidopsis.

    Science.gov (United States)

    Martel, Catherine; Zhurov, Vladimir; Navarro, Marie; Martinez, Manuel; Cazaux, Marc; Auger, Philippe; Migeon, Alain; Santamaria, M Estrella; Wybouw, Nicky; Diaz, Isabel; Van Leeuwen, Thomas; Navajas, Maria; Grbic, Miodrag; Grbic, Vojislava

    2015-03-01

    The two-spotted spider mite Tetranychus urticae is one of the most significant mite pests in agriculture, feeding on more than 1,100 plant hosts, including model plants Arabidopsis thaliana and tomato, Solanum lycopersicum. Here, we describe timecourse tomato transcriptional responses to spider mite feeding and compare them with Arabidopsis in order to determine conserved and divergent defense responses to this pest. To refine the involvement of jasmonic acid (JA) in mite-induced responses and to improve tomato Gene Ontology annotations, we analyzed transcriptional changes in the tomato JA-signaling mutant defenseless1 (def-1) upon JA treatment and spider mite herbivory. Overlay of differentially expressed genes (DEG) identified in def-1 onto those from the timecourse experiment established that JA controls expression of the majority of genes differentially regulated by herbivory. Comparison of defense responses between tomato and Arabidopsis highlighted 96 orthologous genes (of 2,133 DEG) that were recruited for defense against spider mites in both species. These genes, involved in biosynthesis of JA, phenylpropanoids, flavonoids, and terpenoids, represent the conserved core of induced defenses. The remaining tomato DEG support the establishment of tomato-specific defenses, indicating profound divergence of spider mite-induced responses between tomato and Arabidopsis.

  6. SHINE transcription factors act redundantly to pattern the archetypal surface of Arabidopsis flower organs.

    Science.gov (United States)

    Shi, Jian Xin; Malitsky, Sergey; De Oliveira, Sheron; Branigan, Caroline; Franke, Rochus B; Schreiber, Lukas; Aharoni, Asaph

    2011-05-01

    Floral organs display tremendous variation in their exterior that is essential for organogenesis and the interaction with the environment. This diversity in surface characteristics is largely dependent on the composition and structure of their coating cuticular layer. To date, mechanisms of flower organ initiation and identity have been studied extensively, while little is known regarding the regulation of flower organs surface formation, cuticle composition, and its developmental significance. Using a synthetic microRNA approach to simultaneously silence the three SHINE (SHN) clade members, we revealed that these transcription factors act redundantly to shape the surface and morphology of Arabidopsis flowers. It appears that SHNs regulate floral organs' epidermal cell elongation and decoration with nanoridges, particularly in petals. Reduced activity of SHN transcription factors results in floral organs' fusion and earlier abscission that is accompanied by a decrease in cutin load and modified cell wall properties. SHN transcription factors possess target genes within four cutin- and suberin-associated protein families including, CYP86A cytochrome P450s, fatty acyl-CoA reductases, GSDL-motif lipases, and BODYGUARD1-like proteins. The results suggest that alongside controlling cuticular lipids metabolism, SHNs act to modify the epidermis cell wall through altering pectin metabolism and structural proteins. We also provide evidence that surface formation in petals and other floral organs during their growth and elongation or in abscission and dehiscence through SHNs is partially mediated by gibberellin and the DELLA signaling cascade. This study therefore demonstrates the need for a defined composition and structure of the cuticle and cell wall in order to form the archetypal features of floral organs surfaces and control their cell-to-cell separation processes. Furthermore, it will promote future investigation into the relation between the regulation of organ

  7. ABSCISIC ACID-INSENSITIVE 4 negatively regulates flowering through directly promoting Arabidopsis FLOWERING LOCUS C transcription

    Science.gov (United States)

    Shu, Kai; Chen, Qian; Wu, Yaorong; Liu, Ruijun; Zhang, Huawei; Wang, Shengfu; Tang, Sanyuan; Yang, Wenyu; Xie, Qi

    2016-01-01

    During the life cycle of a plant, one of the major biological processes is the transition from the vegetative to the reproductive stage. In Arabidopsis, flowering time is precisely controlled by extensive environmental and internal cues. Gibberellins (GAs) promote flowering, while abscisic acid (ABA) is considered as a flowering suppressor. However, the detailed mechanism through which ABA inhibits the floral transition is poorly understood. Here, we report that ABSCISIC ACID-INSENSITIVE 4 (ABI4), a key component in the ABA signalling pathway, negatively regulates floral transition by directly promoting FLOWERING LOCUS C (FLC) transcription. The abi4 mutant showed the early flowering phenotype whereas ABI4-overexpressing (OE-ABI4) plants had delayed floral transition. Consistently, quantitative reverse transcription–PCR (qRT–PCR) assay revealed that the FLC transcription level was down-regulated in abi4, but up-regulated in OE-ABI4. The change in FT level was consistent with the pattern of FLC expression. Chromatin immunoprecipitation-qPCR (ChIP-qPCR), electrophoretic mobility shift assay (EMSA), and tobacco transient expression analysis showed that ABI4 promotes FLC expression by directly binding to its promoter. Genetic analysis demonstrated that OE-ABI4::flc-3 could not alter the flc-3 phenotype. OE-FLC::abi4 showed a markedly delayed flowering phenotype, which mimicked OE-FLC::WT, and suggested that ABI4 acts upstream of FLC in the same genetic pathway. Taken together, these findings suggest that ABA inhibits the floral transition by activating FLC transcription through ABI4. PMID:26507894

  8. SHINE transcription factors act redundantly to pattern the archetypal surface of Arabidopsis flower organs.

    Directory of Open Access Journals (Sweden)

    Jian Xin Shi

    2011-05-01

    Full Text Available Floral organs display tremendous variation in their exterior that is essential for organogenesis and the interaction with the environment. This diversity in surface characteristics is largely dependent on the composition and structure of their coating cuticular layer. To date, mechanisms of flower organ initiation and identity have been studied extensively, while little is known regarding the regulation of flower organs surface formation, cuticle composition, and its developmental significance. Using a synthetic microRNA approach to simultaneously silence the three SHINE (SHN clade members, we revealed that these transcription factors act redundantly to shape the surface and morphology of Arabidopsis flowers. It appears that SHNs regulate floral organs' epidermal cell elongation and decoration with nanoridges, particularly in petals. Reduced activity of SHN transcription factors results in floral organs' fusion and earlier abscission that is accompanied by a decrease in cutin load and modified cell wall properties. SHN transcription factors possess target genes within four cutin- and suberin-associated protein families including, CYP86A cytochrome P450s, fatty acyl-CoA reductases, GSDL-motif lipases, and BODYGUARD1-like proteins. The results suggest that alongside controlling cuticular lipids metabolism, SHNs act to modify the epidermis cell wall through altering pectin metabolism and structural proteins. We also provide evidence that surface formation in petals and other floral organs during their growth and elongation or in abscission and dehiscence through SHNs is partially mediated by gibberellin and the DELLA signaling cascade. This study therefore demonstrates the need for a defined composition and structure of the cuticle and cell wall in order to form the archetypal features of floral organs surfaces and control their cell-to-cell separation processes. Furthermore, it will promote future investigation into the relation between the

  9. Arabidopsis MALE STERILITY1 encodes a PHD-type transcription factor and regulates pollen and tapetum development.

    Science.gov (United States)

    Ito, Takuya; Nagata, Noriko; Yoshiba, Yoshu; Ohme-Takagi, Masaru; Ma, Hong; Shinozaki, Kazuo

    2007-11-01

    The Arabidopsis thaliana MALE STERILITY1 (MS1) gene encodes a nuclear protein with Leu zipper-like and PHD-finger motifs and is important for postmeiotic pollen development. Here, we examined MS1 function using both cell biological and molecular biological approaches. We introduced a fusion construct of MS1 and a transcriptional repression domain (MS1-SRDX) into wild-type Arabidopsis, and the transgenic plants showed a semisterile phenotype similar to that of ms1. Since the repression domain can convert various kinds of transcriptional activators to dominant repressors, this suggested that MS1 functioned as a transcriptional activator. The Leu zipper-like region and the PHD motif were required for the MS1 function. Phenotypic analysis of the ms1 mutant and the MS1-SRDX transgenic Arabidopsis indicated that MS1 was involved in formation of pollen exine and pollen cytosolic components as well as tapetum development. Next, we searched for MS1 downstream genes by analyzing publicly available microarray data and identified 95 genes affected by MS1. Using a transgenic ms1 plant showing dexamethasone-inducible recovery of fertility, we further examined whether these genes were immediately downstream of MS1. From these results, we discuss a role of MS1 in pollen and tapetum development and the conservation of MS1 function in flowering plants.

  10. Dominant Repression by Arabidopsis Transcription Factor MYB44 Causes Oxidative Damage and Hypersensitivity to Abiotic Stress

    Directory of Open Access Journals (Sweden)

    Helene Persak

    2014-02-01

    Full Text Available In any living species, stress adaptation is closely linked with major changes of the gene expression profile. As a substrate protein of the rapidly stress-induced mitogen-activated protein kinase MPK3, Arabidopsis transcription factor MYB44 likely acts at the front line of stress-induced re-programming. We recently characterized MYB44 as phosphorylation-dependent positive regulator of salt stress signaling. Molecular events downstream of MYB44 are largely unknown. Although MYB44 binds to the MBSII element in vitro, it has no discernible effect on MBSII-driven reporter gene expression in plant co-transfection assays. This may suggest limited abundance of a synergistic co-regulator. MYB44 carries a putative transcriptional repression (Ethylene responsive element binding factor-associated Amphiphilic Repression, EAR motif. We employed a dominant repressor strategy to gain insights into MYB44-conferred stress resistance. Overexpression of a MYB44-REP fusion markedly compromised salt and drought stress tolerance—the opposite was seen in MYB44 overexpression lines. MYB44-mediated resistance likely results from induction of tolerance-enhancing, rather than from repression of tolerance-diminishing factors. Salt stress-induced accumulation of destructive reactive oxygen species is efficiently prevented in transgenic MYB44, but accelerated in MYB44-REP lines. Furthermore, heterologous overexpression of MYB44-REP caused tissue collapse in Nicotiana. A mechanistic model of MAPK-MYB-mediated enhancement in the antioxidative capacity and stress tolerance is proposed. Genetic engineering of MYB44 variants with higher trans-activating capacity may be a means to further raise stress resistance in crops.

  11. The maternally expressed WRKY transcription factor TTG2 controls lethality in interploidy crosses of Arabidopsis.

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    Brian P Dilkes

    2008-12-01

    Full Text Available The molecular mechanisms underlying lethality of F1 hybrids between diverged parents are one target of speciation research. Crosses between diploid and tetraploid individuals of the same genotype can result in F1 lethality, and this dosage-sensitive incompatibility plays a role in polyploid speciation. We have identified variation in F1 lethality in interploidy crosses of Arabidopsis thaliana and determined the genetic architecture of the maternally expressed variation via QTL mapping. A single large-effect QTL, DR. STRANGELOVE 1 (DSL1, was identified as well as two QTL with epistatic relationships to DSL1. DSL1 affects the rate of postzygotic lethality via expression in the maternal sporophyte. Fine mapping placed DSL1 in an interval encoding the maternal effect transcription factor TTG2. Maternal parents carrying loss-of-function mutations in TTG2 suppressed the F1 lethality caused by paternal excess interploidy crosses. The frequency of cellularization in the endosperm was similarly affected by both natural variation and ttg2 loss-of-function mutants. The simple genetic basis of the natural variation and effects of single-gene mutations suggests that F1 lethality in polyploids could evolve rapidly. Furthermore, the role of the sporophytically active TTG2 gene in interploidy crosses indicates that the developmental programming of the mother regulates the viability of interploidy hybrid offspring.

  12. Functional characterization of Arabidopsis NaCl-inducible WRKY25 and WRKY33 transcription factors in abiotic stresses.

    Science.gov (United States)

    Jiang, Yuanqing; Deyholos, Michael K

    2009-01-01

    Previous microarray analyses of Arabidopsis roots identified two closely related WRKY transcription factors (WRKY25 and WRKY33) among the transcripts that increased in abundance following treatment with NaCl. Here, we report further characterization of these genes, which we found to be inducible by a variety of abiotic stresses in an SOS-pathway independent manner, although WRKY33 induction was dependent on ABA signaling. Transcripts of both genes were detected in roots and leaves, while specific patterns of enrichment were observed in stems and floral buds for WRKY25 and WRKY33, respectively. We also identified upstream intergenic regions from each gene that were sufficient to confer stress-inducible expression on a reporter gene. However, the stress sensitivity of wrky25 null mutants did not differ from wild-type under any assay condition, while wrky33 null mutants and wrky25wrky33 double mutants showed only a moderate increase in NaCl-sensitivity, suggesting functional redundancy with other transcription factors. Nevertheless, overexpression of WRKY25 or WRKY33 was sufficient to increase Arabidopsis NaCl tolerance, while increasing sensitivity to ABA. Through microarray analyses of relevant genotypes, we identified 31 and 208 potential downstream targets of WRKY25 and WRKY33, respectively, most of which contained a W-box in their upstream regions.

  13. AGO6 functions in RNA-mediated transcriptional gene silencing in shoot and root meristems in Arabidopsis thaliana.

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    Changho Eun

    Full Text Available RNA-directed DNA methylation (RdDM is a small interfering RNA (siRNA-mediated epigenetic modification that contributes to transposon silencing in plants. RdDM requires a complex transcriptional machinery that includes specialized RNA polymerases, named Pol IV and Pol V, as well as chromatin remodelling proteins, transcription factors, RNA binding proteins, and other plant-specific proteins whose functions are not yet clarified. In Arabidopsis thaliana, DICER-LIKE3 and members of the ARGONAUTE4 group of ARGONAUTE (AGO proteins are involved, respectively, in generating and using 24-nt siRNAs that trigger methylation and transcriptional gene silencing of homologous promoter sequences. AGO4 is the main AGO protein implicated in the RdDM pathway. Here we report the identification of the related AGO6 in a forward genetic screen for mutants defective in RdDM and transcriptional gene silencing in shoot and root apical meristems in Arabidopsis thaliana. The identification of AGO6, and not AGO4, in our screen is consistent with the primary expression of AGO6 in shoot and root growing points.

  14. Arabidopsis WRKY33 is a key transcriptional regulator of hormonal and metabolic responses toward Botrytis cinerea infection.

    Science.gov (United States)

    Birkenbihl, Rainer P; Diezel, Celia; Somssich, Imre E

    2012-05-01

    The Arabidopsis (Arabidopsis thaliana) transcription factor WRKY33 is essential for defense toward the necrotrophic fungus Botrytis cinerea. Here, we aimed at identifying early transcriptional responses mediated by WRKY33. Global expression profiling on susceptible wrky33 and resistant wild-type plants uncovered massive differential transcriptional reprogramming upon B. cinerea infection. Subsequent detailed kinetic analyses revealed that loss of WRKY33 function results in inappropriate activation of the salicylic acid (SA)-related host response and elevated SA levels post infection and in the down-regulation of jasmonic acid (JA)-associated responses at later stages. This down-regulation appears to involve direct activation of several jasmonate ZIM-domain genes, encoding repressors of the JA-response pathway, by loss of WRKY33 function and by additional SA-dependent WRKY factors. Moreover, genes involved in redox homeostasis, SA signaling, ethylene-JA-mediated cross-communication, and camalexin biosynthesis were identified as direct targets of WRKY33. Genetic studies indicate that although SA-mediated repression of the JA pathway may contribute to the susceptibility of wrky33 plants to B. cinerea, it is insufficient for WRKY33-mediated resistance. Thus, WRKY33 apparently directly targets other still unidentified components that are also critical for establishing full resistance toward this necrotroph.

  15. HORMONOMETER: A Tool for Discerning Transcript Signatures of Hormone Action in the Arabidopsis Transcriptome1[W][OA

    Science.gov (United States)

    Volodarsky, Dina; Leviatan, Noam; Otcheretianski, Andrei; Fluhr, Robert

    2009-01-01

    Plant hormones regulate growth and responses to environmental change. Hormone action ultimately modifies cellular physiological processes and gene activity. To facilitate transcriptome evaluation of novel mutants and environmental responses, there is a need to rapidly assess the possible contribution of hormone action to changes in the levels of gene transcripts. We developed a vector-based algorithm that rapidly compares lists of transcripts yielding correlation values. The application as described here, called HORMONOMETER, was used to analyze hormone-related activity in a transcriptome of Arabidopsis (Arabidopsis thaliana). The veracity of the resultant analysis was established by comparison with cognate and noncognate hormone transcriptomes as well as with mutants and selected plant-environment interactions. The HORMONOMETER accurately predicted correlations between hormone action and biosynthetic mutants for which transcriptome data are available. A high degree of correlation was detected between many hormones, particularly at early time points of hormone action. Unforeseen complexity was detected in the analysis of mutants and in plant-herbivore interactions. The HORMONOMETER provides a diagnostic tool for evaluating the physiological state of being of the plant from the point of view of transcripts regulated by hormones and yields biological insight into the multiple response components that enable plant adaptation to the environment. A Web-based interface has been developed to facilitate external interfacing with this platform. PMID:19535475

  16. EBE, an AP2/ERF transcription factor highly expressed in proliferating cells, affects shoot architecture in Arabidopsis.

    Science.gov (United States)

    Mehrnia, Mohammad; Balazadeh, Salma; Zanor, María-Inés; Mueller-Roeber, Bernd

    2013-06-01

    We report about ERF BUD ENHANCER (EBE; At5g61890), a transcription factor that affects cell proliferation as well as axillary bud outgrowth and shoot branching in Arabidopsis (Arabidopsis thaliana). EBE encodes a member of the APETALA2/ETHYLENE RESPONSE FACTOR (AP2/ERF) transcription factor superfamily; the gene is strongly expressed in proliferating cells and is rapidly and transiently up-regulated in axillary meristems upon main stem decapitation. Overexpression of EBE promotes cell proliferation in growing calli, while the opposite is observed in EBE-RNAi lines. EBE overexpression also stimulates axillary bud formation and outgrowth, while repressing it results in inhibition of bud growth. Global transcriptome analysis of estradiol-inducible EBE overexpression lines revealed 48 EBE early-responsive genes, of which 14 were up-regulated and 34 were down-regulated. EBE activates several genes involved in cell cycle regulation and dormancy breaking, including D-type cyclin CYCD3;3, transcription regulator DPa, and BRCA1-ASSOCIATED RING DOMAIN1. Among the down-regulated genes were DORMANCY-ASSOCIATED PROTEIN1 (AtDRM1), AtDRM1 homolog, MEDIATOR OF ABA-REGULATED DORMANCY1, and ZINC FINGER HOMEODOMAIN5. Our data indicate that the effect of EBE on shoot branching likely results from an activation of genes involved in cell cycle regulation and dormancy breaking.

  17. Different transcript patterns in response to specialist and generalist herbivores in the wild Arabidopsis relative Boechera divaricarpa.

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    Heiko Vogel

    Full Text Available BACKGROUND: Plants defend themselves against herbivorous insects, utilizing both constitutive and inducible defenses. Induced defenses are controlled by several phytohormone-mediated signaling pathways. Here, we analyze transcriptional changes in the North American Arabidopsis relative Boechera divaricarpa in response to larval herbivory by the crucifer specialist lepidopteran Plutella xylostella (diamondback moth and by the generalist lepidopteran Trichoplusia ni (cabbage semilooper, and compare them to wounding and exogenous phytohormone application. METHODOLOGY/PRINCIPAL FINDINGS: We use a custom macroarray constructed from B. divaricarpa herbivory-regulated cDNAs identified by suppression subtractive hybridization and from known stress-responsive A. thaliana genes for transcript profiling after insect herbivory, wounding and in response to jasmonate, salicylate and ethylene. In addition, we introduce path analysis as a novel approach to analyze transcript profiles. Path analyses reveal that transcriptional responses to the crucifer specialist P. xylostella are primarily determined by direct effects of the ethylene and salicylate pathways, whereas responses to the generalist T. ni are influenced by the ethylene and jasmonate pathways. Wound-induced transcriptional changes are influenced by all three pathways, with jasmonate having the strongest effect. CONCLUSIONS/SIGNIFICANCE: Our results show that insect herbivory is distinct from simple mechanical plant damage, and that different lepidopteran herbivores elicit different transcriptional responses.

  18. Protein intrinsic disorder in Arabidopsis NAC transcription factors: transcriptional activation by ANAC013 and ANAC046 and their interactions with RCD1.

    Science.gov (United States)

    O'Shea, Charlotte; Kryger, Mikael; Stender, Emil G P; Kragelund, Birthe B; Willemoës, Martin; Skriver, Karen

    2015-01-15

    Protein ID (intrinsic disorder) plays a significant, yet relatively unexplored role in transcription factors (TFs). In the present paper, analysis of the transcription regulatory domains (TRDs) of six phylogenetically representative, plant-specific NAC [no apical meristem, ATAF (Arabidopsis transcription activation factor), cup-shaped cotyledon] TFs shows that the domains are present in similar average pre-molten or molten globule-like states, but have different patterns of order/disorder and MoRFs (molecular recognition features). ANAC046 (Arabidopsis NAC 046) was selected for further studies because of its simple MoRF pattern and its ability to interact with RCD1 (radical-induced cell death 1). Experiments in yeast and thermodynamic characterization suggest that its single MoRF region is sufficient for both transcriptional activation and interaction with RCD1. The remainder of the large regulatory domain is unlikely to contribute to the interaction, since the domain and truncations thereof have similar affinities for RCD1, which are also similar for ANAC013-RCD1 interactions. However, different enthalpic and entropic contributions to binding were revealed for ANAC046 and ANAC013, suggestive of differences in binding mechanisms. Although substitution of both hydrophobic and acidic residues of the ANAC046 MoRF region abolished binding, substitution of other residues, even with α-helix-breaking proline, was less disruptive. Together, the biophysical analyses suggest that RCD1-ANAC046 complex formation does not involve folding-upon-binding, but rather fuzziness or an unknown structure in ANAC046. We suggest that the ANAC046 regulatory domain functions as an entropic chain with a terminal hot spot interacting with RCD1. RCD1, a cellular hub, may be able to interact with many different TFs by exploiting their ID-based flexibility, as demonstrated for its interactions with ANAC046 and ANAC013.

  19. Phosphorylation of an ERF transcription factor by Arabidopsis MPK3/MPK6 regulates plant defense gene induction and fungal resistance.

    Science.gov (United States)

    Meng, Xiangzong; Xu, Juan; He, Yunxia; Yang, Kwang-Yeol; Mordorski, Breanne; Liu, Yidong; Zhang, Shuqun

    2013-03-01

    Arabidopsis thaliana MPK3 and MPK6, two mitogen-activated protein kinases (MAPKs or MPKs), play critical roles in plant disease resistance by regulating multiple defense responses. Previously, we characterized the regulation of phytoalexin biosynthesis by Arabidopsis MPK3/MPK6 cascade and its downstream WRKY33 transcription factor. Here, we report another substrate of MPK3/MPK6, ETHYLENE RESPONSE FACTOR6 (ERF6), in regulating Arabidopsis defense gene expression and resistance to the necrotrophic fungal pathogen Botrytis cinerea. Phosphorylation of ERF6 by MPK3/MPK6 in either the gain-of-function transgenic plants or in response to B. cinerea infection increases ERF6 protein stability in vivo. Phospho-mimicking ERF6 is able to constitutively activate defense-related genes, especially those related to fungal resistance, including PDF1.1 and PDF1.2, and confers enhanced resistance to B. cinerea. By contrast, expression of ERF6-EAR, in which ERF6 was fused to the ERF-associated amphiphilic repression (EAR) motif, strongly suppresses B. cinerea-induced defense gene expression, leading to hypersusceptibility of the ERF6-EAR transgenic plants to B. cinerea. Different from ERF1, the regulation and function of ERF6 in defensin gene activation is independent of ethylene. Based on these data, we conclude that ERF6, another substrate of MPK3 and MPK6, plays important roles downstream of the MPK3/MPK6 cascade in regulating plant defense against fungal pathogens.

  20. Genome-wide analysis of basic leucine zipper transcription factor families in Arabidopsis thaliana, Oryza saliva and Populus trichocarpa

    Institute of Scientific and Technical Information of China (English)

    JI Qian; ZHANG Liang-sheng; WANG Yi-fei; WANG Jian

    2009-01-01

    The basic leucine zipper (bZIP) transcription factors form a large gene family that is important in pathogen defense, light and stress signaling, etc. The Completed whole genome sequences of model plants Arabidopsis (Arabidopsis thaliana), rice (Oryza saliva) and poplar (Populus trichocarpa) constitute a valuable resource for genome-wide analysis and genomic comparative analysis, as they are representatives of the two major evolutionary lineages within the angiosperms: the monocotyledons and the dicotyledons. In this study, bioinformatics analysis identified 74, 89 and 88 bZIP genes respectively in Arabidopsis, rice and poplar. Moreover, a comprehensive overview of this gene family is presented, including the gene structure, phylogeny, chromosome distribution, conserved motifs. As a result, the plant bZIPs were organized into 10 subfamilies on basis of phylogenetic relationship. Gene duplication events during the family evolution history were also investigated. And it was further concluded that chromosomal/segmental duplication might have played a key role in gene expansion of bZIP gene family.

  1. ZmSOC1, a MADS-box transcription factor from Zea mays, promotes flowering in Arabidopsis.

    Science.gov (United States)

    Zhao, Suzhou; Luo, Yanzhong; Zhang, Zhanlu; Xu, Miaoyun; Wang, Weibu; Zhao, Yangmin; Zhang, Lan; Fan, Yunliu; Wang, Lei

    2014-11-03

    Zea mays is an economically important crop, but its molecular mechanism of flowering remains largely uncharacterized. The gene, SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (SOC1), integrates multiple flowering signals to regulate floral transition in Arabidopsis. In this study, ZmSOC1 was isolated from Zea mays. Sequence alignment and phylogenetic analysis demonstrated that the ZmSOC1 protein contained a highly conserved MADS domain and a typical SOC1 motif. ZmSOC1 protein was localized in the nucleus in protoplasts and showed no transcriptional activation activity in yeast cells. ZmSOC1 was highly expressed in maize reproductive organs, including filaments, ear and endosperm, but expression was very low in embryos; on the other hand, the abiotic stresses could repress ZmSOC1 expression. Overexpression of ZmSOC1 resulted in early flowering in Arabidopsis through increasing the expression of AtLFY and AtAP1. Overall, these results suggest that ZmSOC1 is a flowering promoter in Arabidopsis.

  2. Constitutive production of nitric oxide leads to enhanced drought stress resistance and extensive transcriptional reprogramming in Arabidopsis.

    Science.gov (United States)

    Shi, Haitao; Ye, Tiantian; Zhu, Jian-Kang; Chan, Zhulong

    2014-08-01

    Nitric oxide (NO) is involved in plant responses to many environmental stresses. Transgenic Arabidopsis lines that constitutively express rat neuronal NO synthase (nNOS) were described recently. In this study, it is reported that the nNOS transgenic Arabidopsis plants displayed high levels of osmolytes and increased antioxidant enzyme activities. Transcriptomic analysis identified 601 or 510 genes that were differentially expressed as a consequence of drought stress or nNOS transformation, respectively. Pathway and gene ontology (GO) term enrichment analyses revealed that genes involved in photosynthesis, redox, stress, and phytohormone and secondary metabolism were greatly affected by the nNOS transgene. Several CBF genes and members of zinc finger gene families, which are known to regulate transcription in the stress response, were changed by the nNOS transgene. Genes regulated by both the nNOS transgene and abscisic acid (ABA) treatments were compared and identified, including those for two ABA receptors (AtPYL4 and AtPYL5). Moreover, overexpression of AtPYL4 and AtPYL5 enhanced drought resistance, antioxidant enzyme activity, and osmolyte levels. These observations increase our understanding of the role of NO in drought stress response in Arabidopsis.

  3. An Arabidopsis F-box protein acts as a transcriptional co-factor to regulate floral development.

    Science.gov (United States)

    Chae, Eunyoung; Tan, Queenie K-G; Hill, Theresa A; Irish, Vivian F

    2008-04-01

    Plants flower in response to both environmental and endogenous signals. The Arabidopsis LEAFY (LFY) transcription factor is crucial in integrating these signals, and acts in part by activating the expression of multiple floral homeotic genes. LFY-dependent activation of the homeotic APETALA3 (AP3) gene requires the activity of UNUSUAL FLORAL ORGANS (UFO), an F-box component of an SCF ubiquitin ligase, yet how this regulation is effected has remained unclear. Here, we show that UFO physically interacts with LFY both in vitro and in vivo, and this interaction is necessary to recruit UFO to the AP3 promoter. Furthermore, a transcriptional repressor domain fused to UFO reduces endogenous LFY activity in plants, supporting the idea that UFO acts as part of a transcriptional complex at the AP3 promoter. Moreover, chemical or genetic disruption of proteasome activity compromises LFY-dependent AP3 activation, indicating that protein degradation is required to promote LFY activity. These results define an unexpected role for an F-box protein in functioning as a DNA-associated transcriptional co-factor in regulating floral homeotic gene expression. These results suggest a novel mechanism for promoting flower development via protein degradation and concomitant activation of the LFY transcription factor. This mechanism may be widely conserved, as homologs of UFO and LFY have been identified in a wide array of plant species.

  4. Variation at the transcriptional level among Chinese natural populations of Arabidopsis thaliana in response to cold stress

    Institute of Scientific and Technical Information of China (English)

    HE Fei; KANG JiuQing; ZHOU Xin; SU Zhen; QU LiJia; GU HongYa

    2008-01-01

    The Arabidopsis 25K GeneChip (ATH1, Affymetrix) was used to make a survey of the variation of the transcriptional profiles among 5 Chinese natural populations of Arabidopsis thaliana under cold treatment. In normal growth condition, the expression level of 2.26% (513 genes in the population from Jiujiang, Jiangxi, JXjjx)to 6.52% (1482 genes in the population from Tongliang, Chongqing, CQtlx) genes was 2-fold higher than that of Col ecotype. Under cold treatment, the expression of 12.84% (2920 genes in the population from Chenggu, Shaanxi, SXcgx) to 19.46% (4426 genes in the population from Qinghe, Xinjiang, XJqhx) genes was up- or down-regulated by at least two-fold that of their controls. In general, most of up-regulated genes might be the genes essential for plant surviving at low temperature, such as genes in CBF pathway and the genes responsible for synthesizing molecules accumulated for cold tolerance. However, each natural population had some specific genes induced under cold treat-ment. The data indicated that some of the cold-responding genes were differentiated among the popu-lations distributed in the natural habitats with different climate conditions. CBF3, one of the key tran-scription factor genes in cold responding pathway, showed significant differences in expression among populations. The sequence analysis indicated that the changes in its regulation region caused the dramatic difference in the expression pattern. Further studies on the correlation of the function of the differentially expressed genes and the cold tolerance in different populations may provide some new insight into the molecular mechanism of adaptation to local environment in Arabidopsis thaliana in China.

  5. Phosphorylation of a WRKY transcription factor by two pathogen-responsive MAPKs drives phytoalexin biosynthesis in Arabidopsis.

    Science.gov (United States)

    Mao, Guohong; Meng, Xiangzong; Liu, Yidong; Zheng, Zuyu; Chen, Zhixiang; Zhang, Shuqun

    2011-04-01

    Plant sensing of invading pathogens triggers massive metabolic reprogramming, including the induction of secondary antimicrobial compounds known as phytoalexins. We recently reported that MPK3 and MPK6, two pathogen-responsive mitogen-activated protein kinases, play essential roles in the induction of camalexin, the major phytoalexin in Arabidopsis thaliana. In search of the transcription factors downstream of MPK3/MPK6, we found that WRKY33 is required for MPK3/MPK6-induced camalexin biosynthesis. In wrky33 mutants, both gain-of-function MPK3/MPK6- and pathogen-induced camalexin production are compromised, which is associated with the loss of camalexin biosynthetic gene activation. WRKY33 is a pathogen-inducible transcription factor, whose expression is regulated by the MPK3/MPK6 cascade. Chromatin immunoprecipitation assays reveal that WRKY33 binds to its own promoter in vivo, suggesting a potential positive feedback regulatory loop. Furthermore, WRKY33 is a substrate of MPK3/MPK6. Mutation of MPK3/MPK6 phosphorylation sites in WRKY33 compromises its ability to complement the camalexin induction in the wrky33 mutant. Using a phospho-protein mobility shift assay, we demonstrate that WRKY33 is phosphorylated by MPK3/MPK6 in vivo in response to Botrytis cinerea infection. Based on these data, we conclude that WRKY33 functions downstream of MPK3/MPK6 in reprogramming the expression of camalexin biosynthetic genes, which drives the metabolic flow to camalexin production in Arabidopsis challenged by pathogens.

  6. Stress-and Pathogen-Induced Arabidopsis WRKY48 is a Transcriptional Activator that Represses Plant Basal Defense

    Institute of Scientific and Technical Information of China (English)

    Deng-Hui Xing; Zi-Bing Lai; Zu-Yu Zheng; K. M. Vinod; Bao-Fang Fan; Zhi-Xiang Chen

    2008-01-01

    Plant WRKY transcription factors can function as either positive or negative regulators of plant basal disease resistance. Arabidopsis WRKY48 is induced by mechanical and/or osmotic stress due to infiltration and pathogen infection and, therefore, may play a role in plant defense responses. WRKY48 is localized to the nucleus, recognizes the TrGACC Wbox sequence with a high affinity in vitro and functions in plant cells as a strong transcriptional activator. To determine the biological functions directly, we have isolated loss-of-function T-DNA insertion mutants and generated gain-of-function transgenic overexpression plants for WRKY48 in Arabidopsis. Growth of a virulent strain of the bacterial pathogen Pseudomonas syringae was decreased in the wrky48T-DNA insertion mutants. The enhanced resistance of the loss-of-function mutants was associated with increased induction of salicylic acid-regulated PR1 by the bacterial pathogen. By contrast, transgenic WRKY48-0verexpressing plants support enhanced growth of P syringae and the enhanced susceptibility was associated with reduced expression of defense-related PR genes. These results suggest that WRKY48 is a negative regulator of PR gene expression and basal resistance to the bacterial pathogen P syringae.

  7. Overexpression of Arabidopsis and rice stress genes' inducible transcription factor confers drought and salinity tolerance to rice.

    Science.gov (United States)

    Datta, Karabi; Baisakh, Niranjan; Ganguly, Moumita; Krishnan, Sellapan; Yamaguchi Shinozaki, Kazuko; Datta, Swapan K

    2012-06-01

    Rice yield is greatly affected by environmental stresses such as drought and salinity. In response to the challenge of producing rice plants tolerant to these stresses, we introduced cDNA encoding the transcription factors DREB1A and DREB1B under the control of the stress inducible rd29 promoter. Two different indica rice cultivars were used, BR29, an improved commercially cultivated variety from Bangladesh and IR68899B, an IRRI bred maintainer line for hybrid rice. Agrobacterium mediated transformation of BR29 was done independently with DREB1A isolated from rice and Arabidopsis and DREB1B isolated from rice, whereas biolistic transformation was done with rice- DREB1B in the case of IR68899B. Initial genetic integration was confirmed by PCR and Southern blot analysis. Salinity tolerance was assayed in very young seedlings. Drought stress tests were found to be more reliable when they were carried out at the pre-flowering booting stage. RNA gel blot analysis as well as quantitative PCR analysis was performed to estimate the transcription level under stressed and unstressed conditions. Agronomic performance studies were done with stressed and unstressed plants to compare the yield losses due to dehydration and salt loading stresses. Noticeably enhanced tolerance to dehydration was observed in the plants transformed with DREB1A isolated from Arabidopsis while DREB1B was found to be more effective for salt tolerance.

  8. MIXTA-like transcription factors and WAX INDUCER1/SHINE1 coordinately regulate cuticle development in Arabidopsis and Torenia fournieri.

    Science.gov (United States)

    Oshima, Yoshimi; Shikata, Masahito; Koyama, Tomotsugu; Ohtsubo, Norihiro; Mitsuda, Nobutaka; Ohme-Takagi, Masaru

    2013-05-01

    The waxy plant cuticle protects cells from dehydration, repels pathogen attack, and prevents organ fusion during development. The transcription factor WAX INDUCER1/SHINE1 (WIN1/SHN1) regulates the biosynthesis of waxy substances in Arabidopsis thaliana. Here, we show that the MIXTA-like MYB transcription factors MYB106 and MYB16, which regulate epidermal cell morphology, also regulate cuticle development coordinately with WIN1/SHN1 in Arabidopsis and Torenia fournieri. Expression of a MYB106 chimeric repressor fusion (35S:MYB106-SRDX) and knockout/down of MYB106 and MYB16 induced cuticle deficiencies characterized by organ adhesion and reduction of epicuticular wax crystals and cutin nanoridges. A similar organ fusion phenotype was produced by expression of a WIN1/SHN1 chimeric repressor. Conversely, the dominant active form of MYB106 (35S:MYB106-VP16) induced ectopic production of cutin nanoridges and increased expression of WIN1/SHN1 and wax biosynthetic genes. Microarray experiments revealed that MYB106 and WIN1/SHN1 regulate similar sets of genes, predominantly those involved in wax and cutin biosynthesis. Furthermore, WIN1/SHN1 expression was induced by MYB106-VP16 and repressed by MYB106-SRDX. These results indicate that the regulatory cascade of MIXTA-like proteins and WIN1/SHN1 coordinately regulate cutin biosynthesis and wax accumulation. This study reveals an additional key aspect of MIXTA-like protein function and suggests a unique relationship between cuticle development and epidermal cell differentiation.

  9. Interaction with diurnal and circadian regulation results in dynamic metabolic and transcriptional changes during cold acclimation in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Carmen Espinoza

    Full Text Available In plants, there is a large overlap between cold and circadian regulated genes and in Arabidopsis, we have shown that cold (4°C affects the expression of clock oscillator genes. However, a broader insight into the significance of diurnal and/or circadian regulation of cold responses, particularly for metabolic pathways, and their physiological relevance is lacking. Here, we performed an integrated analysis of transcripts and primary metabolites using microarrays and gas chromatography-mass spectrometry. As expected, expression of diurnally regulated genes was massively affected during cold acclimation. Our data indicate that disruption of clock function at the transcriptional level extends to metabolic regulation. About 80% of metabolites that showed diurnal cycles maintained these during cold treatment. In particular, maltose content showed a massive night-specific increase in the cold. However, under free-running conditions, maltose was the only metabolite that maintained any oscillations in the cold. Furthermore, although starch accumulates during cold acclimation we show it is still degraded at night, indicating significance beyond the previously demonstrated role of maltose and starch breakdown in the initial phase of cold acclimation. Levels of some conventional cold induced metabolites, such as γ-aminobutyric acid, galactinol, raffinose and putrescine, exhibited diurnal and circadian oscillations and transcripts encoding their biosynthetic enzymes often also cycled and preceded their cold-induction, in agreement with transcriptional regulation. However, the accumulation of other cold-responsive metabolites, for instance homoserine, methionine and maltose, did not have consistent transcriptional regulation, implying that metabolic reconfiguration involves complex transcriptional and post-transcriptional mechanisms. These data demonstrate the importance of understanding cold acclimation in the correct day-night context, and are further

  10. A brassinosteroid transcriptional network revealed by genome-wide identification of BESI target genes in Arabidopsis thaliana.

    Science.gov (United States)

    Yu, Xiaofei; Li, Lei; Zola, Jaroslaw; Aluru, Maneesha; Ye, Huaxun; Foudree, Andrew; Guo, Hongqing; Anderson, Sarah; Aluru, Srinivas; Liu, Peng; Rodermel, Steve; Yin, Yanhai

    2011-02-01

    Brassinosteroids (BRs) are important regulators for plant growth and development. BRs signal to control the activities of the BES1 and BZR1 family transcription factors. The transcriptional network through which BES1 and BZR regulate large number of target genes is mostly unknown. By combining chromatin immunoprecipitation coupled with Arabidopsis tiling arrays (ChIP-chip) and gene expression studies, we have identified 1609 putative BES1 target genes, 404 of which are regulated by BRs and/or in gain-of-function bes1-D mutant. BES1 targets contribute to BR responses and interactions with other hormonal or light signaling pathways. Computational modeling of gene expression data using Algorithm for the Reconstruction of Accurate Cellular Networks (ARACNe) reveals that BES1-targeted transcriptional factors form a gene regulatory network (GRN). Mutants of many genes in the network displayed defects in BR responses. Moreover, we found that BES1 functions to inhibit chloroplast development by repressing the expression of GLK1 and GLK2 transcription factors, confirming a hypothesis generated from the GRN. Our results thus provide a global view of BR regulated gene expression and a GRN that guides future studies in understanding BR-regulated plant growth.

  11. Arabidopsis BRCA2 and RAD51 proteins are specifically involved in defense gene transcription during plant immune responses

    Science.gov (United States)

    Wang, Shui; Durrant, Wendy E.; Song, Junqi; Spivey, Natalie W.; Dong, Xinnian

    2010-01-01

    Systemic acquired resistance (SAR) is a plant immune response associated with both transcriptional reprogramming and increased homologous DNA recombination (HR). SNI1 is a negative regulator of SAR and HR, as indicated by the increased basal expression of defense genes and HR in sni1. We found that the sni1 phenotypes are rescued by mutations in BREAST CANCER 2 (BRCA2). In humans, BRCA2 is a mediator of RAD51 in pairing of homologous DNA. Mutations in BRCA2 cause predisposition to breast/ovarian cancers; however, the role of the BRCA2–RAD51 complex in transcriptional regulation remains unclear. In Arabidopsis, both brca2 and rad51 were found to be hypersusceptible not only to genotoxic substances, but also to pathogen infections. A whole-genome microarray analysis showed that downstream of NPR1, BRCA2A is a major regulator of defense-related gene transcription. ChIP demonstrated that RAD51 is specifically recruited to the promoters of defense genes during SAR. This recruitment is dependent on the SAR signal salicylic acid (SA) and on the function of BRCA2. This study provides the molecular evidence showing that the BRCA2–RAD51 complex, known for its function in HR, also plays a direct and specific role in transcription regulation during plant immune responses. PMID:21149701

  12. Tracking transcription factor mobility and interaction in arabidopsis roots with fluorescence correlation spectroscopy

    NARCIS (Netherlands)

    Clark, Natalie M.; Hinde, Elizabeth; Hinde, Elizabeth; Fisher, Adam P.; Crosti, Giuseppe; Blilou, Ikram; Gratton, Enrico; Benfey, Philip N.; Sozzani, Rosangela

    2016-01-01

    To understand complex regulatory processes in multicellular organisms, it is critical to be able to quantitatively analyze protein movement and protein-protein interactions in time and space. During Arabidopsis development, the intercellular movement of SHORTROOT (SHR) and subsequent interaction

  13. Arabidopsis TRANSPARENT TESTA GLABRA2 is directly regulated by R2R3 MYB transcription factors and is involved in regulation of GLABRA2 transcription in epidermal differentiation.

    Science.gov (United States)

    Ishida, Tetsuya; Hattori, Sayoko; Sano, Ryosuke; Inoue, Kayoko; Shirano, Yumiko; Hayashi, Hiroaki; Shibata, Daisuke; Sato, Shusei; Kato, Tomohiko; Tabata, Satoshi; Okada, Kiyotaka; Wada, Takuji

    2007-08-01

    Arabidopsis thaliana TRANSPARENT TESTA GLABRA2 (TTG2) encodes a WRKY transcription factor and is expressed in young leaves, trichomes, seed coats, and root hairless cells. An examination of several trichome and root hair mutants indicates that MYB and bHLH genes regulate TTG2 expression. Two MYB binding sites in the TTG2 5' regulatory region act as cis regulatory elements and as direct targets of R2R3 MYB transcription factors such as WEREWOLF, GLABRA1, and TRANSPARENT TESTA2. Mutations in TTG2 cause phenotypic defects in trichome development and seed color pigmentation. Transgenic plants expressing a chimeric repressor version of the TTG2 protein (TTG2:SRDX) showed defects in trichome formation, anthocyanin accumulation, seed color pigmentation, and differentiation of root hairless cells. GLABRA2 (GL2) expression was markedly reduced in roots of ProTTG2:TTG2:SRDX transgenic plants, suggesting that TTG2 is involved in the regulation of GL2 expression, although GL2 expression in the ttg2 mutant was similar to that in the wild type. Our analysis suggests a new step in a regulatory cascade of epidermal differentiation, in which complexes containing R2R3 MYB and bHLH transcription factors regulate the expression of TTG2, which then regulates GL2 expression with complexes containing R2R3 MYB and bHLH in the differentiation of trichomes and root hairless cells.

  14. Melatonin induces the transcripts of CBF/DREB1s and their involvement in both abiotic and biotic stresses in Arabidopsis.

    Science.gov (United States)

    Shi, Haitao; Qian, Yongqiang; Tan, Dun-Xian; Reiter, Russel J; He, Chaozu

    2015-10-01

    Melatonin (N-acetyl-5-methoxytryptamine) is a naturally occurring small molecule that acts as an important secondary messenger in plant stress responses. However, the mechanism underlying the melatonin-mediated signaling pathway in plant stress responses has not been established. C-repeat-binding factors (CBFs)/Drought response element Binding 1 factors (DREB1s) encode transcription factors that play important roles in plant stress responses. This study has determined that endogenous melatonin and transcripts level of CBFs (AtCBF1, AtCBF2, and AtCBF3) in Arabidopsis leaves were significantly induced by salt, drought, and cold stresses and by pathogen Pseudomonas syringe pv. tomato (Pst) DC3000 infection. Moreover, both exogenous melatonin treatment and overexpression of CBFs conferred enhanced resistance to both abiotic and biotic stresses in Arabidopsis. Notably, AtCBFs and exogenous melatonin treatment positively regulated the mRNA expression of several stress-responsive genes (COR15A, RD22, and KIN1) and accumulation of soluble sugars content such as sucrose in Arabidopsis under control and stress conditions. Additionally, exogenous sucrose also conferred improved resistance to both abiotic and biotic stresses in Arabidopsis. Taken together, this study indicates that AtCBFs confer enhanced resistance to both abiotic and biotic stresses, and AtCBF-mediated signaling pathway and sugar accumulation may be involved in melatonin-mediated stress response in Arabidopsis, at least partially.

  15. TCP transcription factors are critical for the coordinated regulation of isochorismate synthase 1 expression in Arabidopsis thaliana.

    Science.gov (United States)

    Wang, Xiaoyan; Gao, Jiong; Zhu, Zheng; Dong, Xianxin; Wang, Xiaolei; Ren, Guodong; Zhou, Xin; Kuai, Benke

    2015-04-01

    Salicylic acid (SA) plays an important role in various aspects of plant development and responses to stresses. To elucidate the sophisticated regulatory mechanism of SA synthesis and signaling, we used a yeast one-hybrid system to screen for regulators of isochorismate synthase 1 (ICS1), a gene encoding the key enzyme in SA biosynthesis in Arabidopsis thaliana. A TCP family transcription factor AtTCP8 was initially identified as a candidate regulator of ICS1. The regulation of ICS1 by TCP proteins is supported by the presence of a typical TCP binding site in the ICS1 promoter. The binding of TCP8 to this site was confirmed by in vitro and in vivo assays. Expression patterns of TCP8 and its corresponding gene TCP9 largely overlapped with ICS1 under pathogen attack. A significant reduction in the expression of ICS1 during immune responses was observed in the tcp8 tcp9 double mutant. We also detected strong interactions between TCP8 and SAR deficient 1 (SARD1), WRKY family transcription factor 28 (WRKY28), NAC (NAM/ATAF1,ATAF2/CUC2) family transcription factor 019 (NAC019), as well as among TCP8, TCP9 and TCP20, suggesting a complex coordinated regulatory mechanism underlying ICS1 expression. Our results collectively demonstrate that TCP proteins are involved in the orchestrated regulation of ICS1 expression, with TCP8 and TCP9 being verified as major representatives.

  16. A wheat salinity-induced WRKY transcription factor TaWRKY93 confers multiple abiotic stress tolerance in Arabidopsis thaliana.

    Science.gov (United States)

    Qin, Yuxiang; Tian, Yanchen; Liu, Xiuzhi

    2015-08-21

    Wheat is an important crop in the world. But most of the cultivars are salt sensitive, and often adversely affected by salt stress. WRKY transcription factors play a major role in plant responses to salt stress, but the effective salinity regulatory WRKYs identified in bread wheat are limited and the mechanism of salt stress tolerance is also not well explored. Here, we identified a salt (NaCl) induced class II WRKY transcription factor TaWRKY93. Its transcript level was strongly induced by salt (NaCl) and exogenous abscisic acid (ABA). Over-expression of TaWRKY93 in Arabidopsis thaliana enhanced salt (NaCl), drought, low temperature and osmotic (mannitol) stress tolerance, mainly demonstrated by transgenic plants forming longer primary roots or more lateral roots on MS plates supplemented with NaCl and mannitol individually, higher survival rate under drought and low temperature stress. Further, transgenic plants maintained a more proline content, higher relative water content and less electrolyte leakage than the wild type plants. The transcript abundance of a series of abiotic stress-related genes was up-regulated in the TaWRKY93 transgenic plants. In summary, TaWRKY93 is a new positive regulator of abiotic stress, it may increase salinity, drought and low temperature stress tolerance through enhancing osmotic adjustment, maintaining membrane stability and increasing transcription of stress related genes, and contribute to the superior agricultural traits of SR3 through promoting root development. It can be used as a candidate gene for wheat transgenic engineering breeding against abiotic stress.

  17. Arabidopsis Ovate Family Proteins, a Novel Transcriptional Repressor Family, Control Multiple Aspects of Plant Growth and Development

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shucai [University of British Columbia, Vancouver; Chang, Ying [Northeast Agricultural University; Guo, Jianjun [Harvard University; Zeng, Qingning [University of British Columbia, Vancouver; Ellis, Brian [University of British Columbia, Vancouver; Chen, Jay [ORNL

    2011-01-01

    BACKGROUND: The Arabidopsis genome contains 18 genes that are predicted to encode Ovate Family Proteins (AtOFPs), a protein family characterized by a conserved OVATE domain, an approximately 70-amino acid domain that was originally found in tomato OVATE protein. Among AtOFP family members, AtOFP1 has been shown to suppress cell elongation, in part, by suppressing the expression of AtGA20ox1, AtOFP4 has been shown to regulate secondary cell wall formation by interact with KNOTTED1-LIKE HOMEODOMAIN PROTEIN 7 (KNAT7), and AtOFP5 has been shown to regulate the activity of a BEL1-LIKEHOMEODOMAIN 1(BLH1)-KNAT3 complex during early embryo sac development, but little is known about the function of other AtOFPs. METHODOLOGY/PRINCIPAL FINDINGS: We demonstrated here that AtOFP proteins could function as effective transcriptional repressors in the Arabidopsis protoplast transient expression system. The analysis of loss-of-function alleles of AtOFPs suggested AtOFP genes may have overlapping function in regulating plant growth and development, because none of the single mutants identified, including T-DNA insertion mutants in AtOFP1, AtOFP4, AtOFP8, AtOFP10, AtOFP15 and AtOFP16, displayed any apparent morphological defects. Further, Atofp1 Atofp4 and Atofp15 Atofp16 double mutants still did not differ significantly from wild-type. On the other hand, plants overexpressing AtOFP genes displayed a number of abnormal phenotypes, which could be categorized into three distinct classes, suggesting that AtOFP genes may also have diverse functions in regulating plant growth and development. Further analysis suggested that AtOFP1 regulates cotyledon development in a postembryonic manner, and global transcript profiling revealed that it suppress the expression of many other genes. CONCLUSIONS/SIGNIFICANCE: Our results showed that AtOFPs function as transcriptional repressors and they regulate multiple aspects of plant growth and development. These results provided the first overview of a

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

    Directory of Open Access Journals (Sweden)

    Nair Prasanth

    2012-11-01

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

  19. Post-transcriptional regulation of ethylene perception and signaling in Arabidopsis

    Energy Technology Data Exchange (ETDEWEB)

    Schaller, George Eric

    2014-03-19

    The simple gas ethylene functions as an endogenous regulator of plant growth and development, and modulates such energy relevant processes as photosynthesis and biomass accumulation. Ethylene is perceived in the plant Arabidopsis by a five-member family of receptors related to bacterial histidine kinases. Our data support a general model in which the receptors exist as parts of larger protein complexes. Our goals have been to (1) characterize physical interactions among members of the signaling complex; (2) the role of histidine-kinase transphosphorylation in signaling by the complex; and (3) the role of a novel family of proteins that regulate signal output by the receptors.

  20. Density-dependent interference of aphids with caterpillar-induced defenses in Arabidopsis: involvement of phytohormones and transcription factors.

    Science.gov (United States)

    Kroes, Anneke; van Loon, Joop J A; Dicke, Marcel

    2015-01-01

    In nature, plants are exposed to attacks by multiple herbivore species at the same time. To cope with these attacks, plants regulate defenses with the production of hormones such as salicylic acid (SA) and jasmonic acid (JA). Because herbivore densities are dynamic in time, this may affect plant-mediated interactions between different herbivores attacking at the same time. In Arabidopsis thaliana, feeding by Brevicoryne brassicae aphids interferes with induced defenses against Plutella xylostella caterpillars. This is density dependent: at a low aphid density, the growth rate of P. xylostella was increased, whereas caterpillars feeding on plants colonized by aphids at a high density have a reduced growth rate. Growth of P. xylostella larvae was unaffected on sid2-1 or on dde2-2 mutant plants when feeding simultaneously with a low or high aphid density. This shows that aphid interference with caterpillar-induced defenses requires both SA and JA signal transduction pathways. Transcriptional analysis revealed that simultaneous feeding by caterpillars and aphids at a low density induced the expression of the SA transcription factor gene WRKY70 whereas expression of WRKY70 was lower in plants induced with both caterpillars and a high aphid density. Interestingly, the expression of the JA transcription factor gene MYC2 was significantly higher in plants simultaneously attacked by aphids at a high density and caterpillars. These results indicate that a lower expression level of WRKY70 leads to significantly higher MYC2 expression through SA-JA cross-talk. Thus, plant-mediated interactions between aphids and caterpillars are density dependent and involve phytohormonal cross-talk and differential activation of transcription factors.

  1. The DOF transcription factor Dof5.1 influences leaf axial patterning by promoting Revoluta transcription in Arabidopsis

    KAUST Repository

    Kim, Hyungsae

    2010-10-05

    Dof proteins are transcription factors that have a conserved single zinc finger DNA-binding domain. In this study, we isolated an activation tagging mutant Dof5.1-D exhibiting an upward-curling leaf phenotype due to enhanced expression of the REV gene that is required for establishing adaxialabaxial polarity. Dof5.1-D plants also had reduced transcript levels for IAA6 and IAA19 genes, indicating an altered auxin biosynthesis in Dof5.1-D. An electrophoretic mobility shift assay using the Dof5.1 DNA-binding motif and the REV promoter region indicated that the DNA-binding domain of Dof5.1 binds to a TAAAGT motif located in the 5′-distal promoter region of the REV promoter. Further, transient and chromatin immunoprecipitation assays verified binding activity of the Dof5.1 DNA-binding motif with the REV promoter. Consistent with binding assays, constitutive over-expression of the Dof5.1 DNA-binding domain in wild-type plants caused a downward-curling phenotype, whereas crossing Dof5.1-D to a rev mutant reverted the upward-curling phenotype of the Dof5.1-D mutant leaf to the wild-type. These results suggest that the Dof5.1 protein directly binds to the REV promoter and thereby regulates adaxialabaxial polarity. © 2010 Blackwell Publishing Ltd.

  2. Biphasic regulation of the transcription factor ABORTED MICROSPORES (AMS) is essential for tapetum and pollen development in Arabidopsis.

    Science.gov (United States)

    Ferguson, Alison C; Pearce, Simon; Band, Leah R; Yang, Caiyun; Ferjentsikova, Ivana; King, John; Yuan, Zheng; Zhang, Dabing; Wilson, Zoe A

    2017-01-01

    Viable pollen is essential for plant reproduction and crop yield. Its production requires coordinated expression at specific stages during anther development, involving early meiosis-associated events and late pollen wall formation. The ABORTED MICROSPORES (AMS) transcription factor is a master regulator of sporopollenin biosynthesis, secretion and pollen wall formation in Arabidopsis. Here we show that it has complex regulation and additional essential roles earlier in pollen formation. An inducible-AMS reporter was created for functional rescue, protein expression pattern analysis, and to distinguish between direct and indirect targets. Mathematical modelling was used to create regulatory networks based on wild-type RNA and protein expression. Dual activity of AMS was defined by biphasic protein expression in anther tapetal cells, with an initial peak around pollen meiosis and then later during pollen wall development. Direct AMS-regulated targets exhibit temporal regulation, indicating that additional factors are associated with their regulation. We demonstrate that AMS biphasic expression is essential for pollen development, and defines distinct functional activities during early and late pollen development. Mathematical modelling suggests that AMS may competitively form a protein complex with other tapetum-expressed transcription factors, and that biphasic regulation is due to repression of upstream regulators and promotion of AMS protein degradation.

  3. MYB56 Encoding a R2R3 MYB Transcription Factor Regulates Seed Size in Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    Yanjie Zhang; Wanqi Liang; Jianxin Shi; Jie Xu; Dabing Zhang

    2013-01-01

    Plant seed size is tightly regulated by the development of seed coat, embryo, and endosperm;however, currently, its underlying mechanism remains unclear. In this study, we revealed a regulatory role of an R2R3 MYB transcription factor MYB56 in controlling seed size specifically in Arabidopsis thaliana L. Loss-of-function or knock-down of MYB56 yielded smaller seeds as compared with the wild type. Conversely, overexpression of MYB56 produced larger seeds. Further observation using semi-thin sections showed that myb56 developed smaller contracted endothelial cells and reduced cell number in the outer integument layer of the seed coat during the seed development;by contrast, MYB56 overexpressing lines had expanded endothelial cells and increased cell number in the outer integument layer of the seed coat, suggesting the essential role of MYB56 in regulating seed development. In addition, reciprocal cross-analysis showed that MYB56 affected the seed development maternally. MYB56 was shown to be dominantly expressed in developing seeds, consistently with its function in seed development. Moreover, quantitative reverse transcription polymerase chain reaction analysis revealed that MYB56 regulates the expression of genes involved in cell wall metabolism such as cell division and expansion. Altogether, our results demonstrated that MYB56 represents an unknown pathway for positively controlling the seed size.

  4. The Arabidopsis AP2/ERF Transcription Factor RAP2.11 Modulates Plant Response to Low-Potassium Conditions

    Institute of Scientific and Technical Information of China (English)

    Min Jung Kim; Daniel Ruzicka; Ryoung Shin; Daniel P.Schachtman

    2012-01-01

    Plants respond to low-nutrient conditions through metabolic and morphology changes that increase their ability to survive and grow.The transcription factor RAP2.11 was identified as a component in the response to low potassium through regulation of the high-affinity K+ uptake transporter AtHAK5 and other components of the lowpotassium signal transduction pathway.RAP2.11 was identified through the activation tagging of Arabidopsis lines that contained a luciferase marker driven by the AtHAK5 promoter that is normally only induced by low potassium.This factor bound to a GCC-box of the AtHAK5 promoter in vitro and in vivo.Transcript profiling revealed that a large number of genes were up-regulated in roots by RAP2.11 overexpression.Many regulated genes were identified to be in functional categories that are important in low-K+ signaling.These categories included ethylene signaling,reactive oxygen species production,and calcium signaling.Promoter regions of the up-regulated genes were enriched in the GCCGGC motif also contained in the AtHAK5 promoter.These results suggest that RAP2.11 regulates AtHAK5 expression under low-K+ conditions and also contributes to a coordinated response to low-potassium conditions through the regulation of other genes in the low-K+ signaling cascade.

  5. ZmNAC55, a maize stress-responsive NAC transcription factor, confers drought resistance in transgenic Arabidopsis.

    Science.gov (United States)

    Mao, Hude; Yu, Lijuan; Han, Ran; Li, Zhanjie; Liu, Hui

    2016-08-01

    Abiotic stress has been shown to significantly limit the growth and productivity of crops. NAC transcription factors play essential roles in response to various abiotic stresses. However, only little information regarding stress-related NAC genes is available in maize. Here, we cloned a maize NAC transcription factor ZmNAC55 and identified its function in drought stress. Transient expression and transactivation assay demonstrated that ZmNAC55 was localized in the nucleus and had transactivation activity. Expression analysis of ZmNAC55 in maize showed that this gene was induced by drought, high salinity and cold stresses and by abscisic acid (ABA). Promoter analysis demonstrated that multiple stress-related cis-acting elements exist in promoter region of ZmNAC55. Overexpression of ZmNAC55 in Arabidopsis led to hypersensitivity to ABA at the germination stage, but enhanced drought resistence compared to wild-type seedlings. Transcriptome analysis identified a number of differentially expressed genes between 35S::ZmNAC55 transgenic and wild-type plants, and many of which are involved in stress response, including twelve qRT-PCR confirmed well-known drought-responsive genes. These results highlight the important role of ZmNAC55 in positive regulates of drought resistence, and may have potential applications in transgenic breeding of drought-tolerant crops.

  6. A transcriptional analysis of carotenoid, chlorophyll and plastidial isoprenoid biosynthesis genes during development and osmotic stress responses in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Vallabhaneni Ratnakar

    2011-05-01

    Full Text Available Abstract Background The carotenoids are pure isoprenoids that are essential components of the photosynthetic apparatus and are coordinately synthesized with chlorophylls in chloroplasts. However, little is known about the mechanisms that regulate carotenoid biosynthesis or the mechanisms that coordinate this synthesis with that of chlorophylls and other plastidial synthesized isoprenoid-derived compounds, including quinones, gibberellic acid and abscisic acid. Here, a comprehensive transcriptional analysis of individual carotenoid and isoprenoid-related biosynthesis pathway genes was performed in order to elucidate the role of transcriptional regulation in the coordinated synthesis of these compounds and to identify regulatory components that may mediate this process in Arabidopsis thaliana. Results A global microarray expression correlation analysis revealed that the phytoene synthase gene, which encodes the first dedicated and rate-limiting enzyme of carotenogenesis, is highly co-expressed with many photosynthesis-related genes including many isoprenoid-related biosynthesis pathway genes. Chemical and mutant analysis revealed that induction of the co-expressed genes following germination was dependent on gibberellic acid and brassinosteroids (BR but was inhibited by abscisic acid (ABA. Mutant analyses further revealed that expression of many of the genes is suppressed in dark grown plants by Phytochrome Interacting transcription Factors (PIFs and activated by photoactivated phytochromes, which in turn degrade PIFs and mediate a coordinated induction of the genes. The promoters of PSY and the co-expressed genes were found to contain an enrichment in putative BR-auxin response elements and G-boxes, which bind PIFs, further supporting a role for BRs and PIFs in regulating expression of the genes. In osmotically stressed root tissue, transcription of Calvin cycle, methylerythritol 4-phosphate pathway and carotenoid biosynthesis genes is induced

  7. A transcriptional analysis of carotenoid, chlorophyll and plastidial isoprenoid biosynthesis genes during development and osmotic stress responses in Arabidopsis thaliana

    KAUST Repository

    Meier, Stuart

    2011-05-19

    Background: The carotenoids are pure isoprenoids that are essential components of the photosynthetic apparatus and are coordinately synthesized with chlorophylls in chloroplasts. However, little is known about the mechanisms that regulate carotenoid biosynthesis or the mechanisms that coordinate this synthesis with that of chlorophylls and other plastidial synthesized isoprenoid-derived compounds, including quinones, gibberellic acid and abscisic acid. Here, a comprehensive transcriptional analysis of individual carotenoid and isoprenoid-related biosynthesis pathway genes was performed in order to elucidate the role of transcriptional regulation in the coordinated synthesis of these compounds and to identify regulatory components that may mediate this process in Arabidopsis thaliana.Results: A global microarray expression correlation analysis revealed that the phytoene synthase gene, which encodes the first dedicated and rate-limiting enzyme of carotenogenesis, is highly co-expressed with many photosynthesis-related genes including many isoprenoid-related biosynthesis pathway genes. Chemical and mutant analysis revealed that induction of the co-expressed genes following germination was dependent on gibberellic acid and brassinosteroids (BR) but was inhibited by abscisic acid (ABA). Mutant analyses further revealed that expression of many of the genes is suppressed in dark grown plants by Phytochrome Interacting transcription Factors (PIFs) and activated by photoactivated phytochromes, which in turn degrade PIFs and mediate a coordinated induction of the genes. The promoters of PSY and the co-expressed genes were found to contain an enrichment in putative BR-auxin response elements and G-boxes, which bind PIFs, further supporting a role for BRs and PIFs in regulating expression of the genes. In osmotically stressed root tissue, transcription of Calvin cycle, methylerythritol 4-phosphate pathway and carotenoid biosynthesis genes is induced and uncoupled from that of

  8. A membrane-tethered transcription factor ANAC089 negatively regulates floral initiation in Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The plant-specific NAC (NAM, ATAF1/2,and CUC2) transcription factors have a regulatory function in developmental processes and stress responses. Notably a group of NAC members named NTLs (NTM1-Like) are membrane-tethered, ensuring plants rapidly respond to developmental changes and environmental stimuli. Our results indicated that ANAC089 was a membrane-tethered transcription factor and its truncated form was responsible for the physiological function in flowering time control.

  9. Diverse Transcriptional Programs Associated with Environmental Stress and Hormones in the Arabidopsis Receptor-Like Kinase Gene Family

    Institute of Scientific and Technical Information of China (English)

    Lee Chae; Sylvia Sudat; Sandrine Dudoit; Tong Zhu; Sheng Luan

    2009-01-01

    The genome of Arabidopsis thaliana encodes more than 600 receptor-like kinase (RLK) genes, by far the dominant class of receptors found in land plants. Although similar to the mammalian receptor tyrosine kinases, plant RLKs are serine/threonine kinases that represent a novel signaling innovation unique to plants and, consequently, an excellent opportunity to understand how extracellular signaling evolved and functions in plants as opposed to animals. RLKs are predicted to be major components of the signaling pathways that allow plants to respond to environmental and developmental conditions. However, breakthroughs in identifying these processes have been limited to only a handful of individual RLKs. Here, we used a Syngenta custom Arabidopsis GeneChip array to compile a detailed profile of the transcriptional activity of 604 receptor-like kinase genes after exposure to a cross-section of known signaling factors in plants,including abiotic stresses, biotic stresses, and hormones. In the 68 experiments comprising the study, we found that 582 of the 604 RLK genes displayed a two-fold or greater change in expression to at least one of 12 types of treatments, thereby providing a large body of experimental evidence for targeted functional screens of individual RLK genes. We investigated whether particular subfamilies of RLK genes are responsive to specific types of signals and found that each subfamily displayed broad ranges of expression, as opposed to being targeted towards particular signal classes. Finally, by analyzing the divergence of sequence and gene expression among the RLK subfamilies, we present evidence as to the functional basis for the expansion of the RLKs and how this expansion may have affected conservation and divergences in their function. Taken as a whole, our study represents a preliminary, working model of processes and interactions in which the members of the RLK gene family may be involved, where such information has remained elusive for so many

  10. Transcription factors WRKY70 and WRKY11 served as regulators in rhizobacterium Bacillus cereus AR156-induced systemic resistance to Pseudomonas syringae pv. tomato DC3000 in Arabidopsis.

    Science.gov (United States)

    Jiang, Chun-Hao; Huang, Zi-Yang; Xie, Ping; Gu, Chun; Li, Ke; Wang, Da-Chen; Yu, Yi-Yang; Fan, Zhi-Hang; Wang, Chun-Juan; Wang, Yun-Peng; Guo, Ya-Hui; Guo, Jian-Hua

    2016-01-01

    The activation of both the SA and JA/ETsignalling pathways may lead to more efficient general and broad resistance to Pst DC3000 by non-pathogenic rhizobacteria. However, the mechanisms that govern this simultaneous activation are unclear. Using Arabidopsis as a model system, two transcription factors, WRKY11 and WRKY70, were identified as important regulators involved in Induced Systemic Resistance (ISR) triggered by Bacillus cereus AR156. The results revealed that AR156 treatment significantly stimulated the transcription of WRKY70, but suppressed that of WRKY11 in Arabidopsis leaves. Furthermore, they were shown to be required for AR156 enhancing the activation of cellular defence responses and the transcription level of the plant defence response gene. Overexpression of the two transcription factors in Arabidopsis also showed that they were essential for AR156 to elicit ISR. AR156-triggered ISR was completely abolished in the double mutant of the two transcription factors, but still partially retained in the single mutants, indicating that the regulation of the two transcription factors depend on two different pathways. The target genes of the two transcription factors and epistasis analysis suggested that WRKY11 regulated AR156-triggered ISR through activating the JA signalling pathway, and WRKY70 regulated the ISR through activating the SA signalling pathway. In addition, both WRKY11 and WRKY70 modulated AR156-triggered ISR in a NPR1-dependent manner. In conclusion, WRKY11 and WRKY70 played an important role in regulating the signalling transduction pathways involved in AR156-triggered ISR. This study is the first to illustrate the mechanism by which a single rhizobacterium elicits ISR by simultaneously activating both the SA and JA/ET signalling pathways.

  11. Within and between whorls: comparative transcriptional profiling of Aquilegia and Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Claudia Voelckel

    Full Text Available BACKGROUND: The genus Aquilegia is an emerging model system in plant evolutionary biology predominantly because of its wide variation in floral traits and associated floral ecology. The anatomy of the Aquilegia flower is also very distinct. There are two whorls of petaloid organs, the outer whorl of sepals and the second whorl of petals that form nectar spurs, as well as a recently evolved fifth whorl of staminodia inserted between stamens and carpels. METHODOLOGY/PRINCIPAL FINDINGS: We designed an oligonucleotide microarray based on EST sequences from a mixed tissue, normalized cDNA library of an A. formosa x A. pubescens F2 population representing 17,246 unigenes. We then used this array to analyze floral gene expression in late pre-anthesis stage floral organs from a natural A. formosa population. In particular, we tested for gene expression patterns specific to each floral whorl and to combinations of whorls that correspond to traditional and modified ABC model groupings. Similar analyses were performed on gene expression data of Arabidopsis thaliana whorls previously obtained using the Ath1 gene chips (data available through The Arabidopsis Information Resource. CONCLUSIONS/SIGNIFICANCE: Our comparative gene expression analyses suggest that 1 petaloid sepals and petals of A. formosa share gene expression patterns more than either have organ-specific patterns, 2 petals of A. formosa and A. thaliana may be independently derived, 3 staminodia express B and C genes similar to stamens but the staminodium genetic program has also converged on aspects of the carpel program and 4 staminodia have unique up-regulation of regulatory genes and genes that have been implicated with defense against microbial infection and herbivory. Our study also highlights the value of comparative gene expression profiling and the Aquilegia microarray in particular for the study of floral evolution and ecology.

  12. The bHLH transcription factor POPEYE regulates response to iron deficiency in Arabidopsis roots.

    Science.gov (United States)

    Long, Terri A; Tsukagoshi, Hironaka; Busch, Wolfgang; Lahner, Brett; Salt, David E; Benfey, Philip N

    2010-07-01

    Global population increases and climate change underscore the need for better comprehension of how plants acquire and process nutrients such as iron. Using cell type-specific transcriptional profiling, we identified a pericycle-specific iron deficiency response and a bHLH transcription factor, POPEYE (PYE), that may play an important role in this response. Functional analysis of PYE suggests that it positively regulates growth and development under iron-deficient conditions. Chromatin immunoprecipitation-on-chip analysis and transcriptional profiling reveal that PYE helps maintain iron homeostasis by regulating the expression of known iron homeostasis genes and other genes involved in transcription, development, and stress response. PYE interacts with PYE homologs, including IAA-Leu Resistant3 (ILR3), another bHLH transcription factor that is involved in metal ion homeostasis. Moreover, ILR3 interacts with a third protein, BRUTUS (BTS), a putative E3 ligase protein, with metal ion binding and DNA binding domains, which negatively regulates the response to iron deficiency. PYE and BTS expression is also tightly coregulated. We propose that interactions among PYE, PYE homologs, and BTS are important for maintaining iron homeostasis under low iron conditions.

  13. A non canonical subtilase attenuates the transcriptional activation of defence responses in Arabidopsis thaliana

    Science.gov (United States)

    Serrano, Irene; Buscaill, Pierre; Audran, Corinne; Pouzet, Cécile; Jauneau, Alain; Rivas, Susana

    2016-01-01

    Proteases play crucial physiological functions in all organisms by controlling the lifetime of proteins. Here, we identified an atypical protease of the subtilase family [SBT5.2(b)] that attenuates the transcriptional activation of plant defence independently of its protease activity. The SBT5.2 gene produces two distinct transcripts encoding a canonical secreted subtilase [SBT5.2(a)] and an intracellular protein [SBT5.2(b)]. Concomitant to SBT5.2(a) downregulation, SBT5.2(b) expression is induced after bacterial inoculation. SBT5.2(b) localizes to endosomes where it interacts with and retains the defence-related transcription factor MYB30. Nuclear exclusion of MYB30 results in its reduced transcriptional activation and, thus, suppressed resistance. sbt5.2 mutants, with abolished SBT5.2(a) and SBT5.2(b) expression, display enhanced defence that is suppressed in a myb30 mutant background. Moreover, overexpression of SBT5.2(b), but not SBT5.2(a), in sbt5.2 plants reverts the phenotypes displayed by sbt5.2 mutants. Overall, we uncover a regulatory mode of the transcriptional activation of defence responses previously undescribed in eukaryotes. DOI: http://dx.doi.org/10.7554/eLife.19755.001 PMID:27685353

  14. AtRTD2: A Reference Transcript Dataset for accurate quantification of alternative splicing and expression changes in Arabidopsis thaliana RNA-seq data

    KAUST Repository

    Zhang, Runxuan

    2016-05-06

    Background Alternative splicing is the major post-transcriptional mechanism by which gene expression is regulated and affects a wide range of processes and responses in most eukaryotic organisms. RNA-sequencing (RNA-seq) can generate genome-wide quantification of individual transcript isoforms to identify changes in expression and alternative splicing. RNA-seq is an essential modern tool but its ability to accurately quantify transcript isoforms depends on the diversity, completeness and quality of the transcript information. Results We have developed a new Reference Transcript Dataset for Arabidopsis (AtRTD2) for RNA-seq analysis containing over 82k non-redundant transcripts, whereby 74,194 transcripts originate from 27,667 protein-coding genes. A total of 13,524 protein-coding genes have at least one alternatively spliced transcript in AtRTD2 such that about 60% of the 22,453 protein-coding, intron-containing genes in Arabidopsis undergo alternative splicing. More than 600 putative U12 introns were identified in more than 2,000 transcripts. AtRTD2 was generated from transcript assemblies of ca. 8.5 billion pairs of reads from 285 RNA-seq data sets obtained from 129 RNA-seq libraries and merged along with the previous version, AtRTD, and Araport11 transcript assemblies. AtRTD2 increases the diversity of transcripts and through application of stringent filters represents the most extensive and accurate transcript collection for Arabidopsis to date. We have demonstrated a generally good correlation of alternative splicing ratios from RNA-seq data analysed by Salmon and experimental data from high resolution RT-PCR. However, we have observed inaccurate quantification of transcript isoforms for genes with multiple transcripts which have variation in the lengths of their UTRs. This variation is not effectively corrected in RNA-seq analysis programmes and will therefore impact RNA-seq analyses generally. To address this, we have tested different genome

  15. Thirty-seven transcription factor genes differentially respond to a harpin protein and affect resistance to the green peach aphid in Arabidopsis

    Indian Academy of Sciences (India)

    Ruoxue Liu; Beibei Lü; Xiaomeng Wang; Chunling Zhang; Shuping Zhang; Jun Qian; Lei Chen; Haojie Shi; Hansong Dong

    2010-09-01

    The harpin protein HrpNEa induces Arabidopsis resistance to the green peach aphid by activating the ethylene signalling pathway and by recruiting EIN2, an essential regulator of ethylene signalling, for a defence response in the plant. We investigated 37 ethylene-inducible Arabidopsis transcription factor genes for their effects on the activation of ethylene signalling and insect defence. Twenty-eight of the 37 genes responded to both ethylene and HrpNEa, and showed either increased or inhibited transcription, while 18 genes showed increased transcription not only by ethylene but also by HrpNEa. In response to HrpNEa, transcription levels of 22 genes increased, with AtMYB44 being the most inducible, six genes had decreased transcript levels, and nine remained unchanged. When Arabidopsis mutants previously generated by mutagenicity at the 37 genes were surveyed, 24 mutants were similar to the wild type plant while four mutants were more resistant and nine mutants were more susceptible than wild type to aphid infestation. Aphid-susceptible mutants showed a greater susceptibility for atmyb15, atmyb38 and atmyb44, which were generated previously by T-DNA insertion into the exon region of AtMYB15 and the promoter regions of AtMYB38 and AtMYB44. The atmyb44 mutant was the most susceptible to aphid infestation and most compromised in induced resistance. Resistance accompanied the expression of PDF1.2, an ethylene signalling marker gene that requires EIN2 for transcription in wild type but not in atmyb15, atmyb38, and atmyb44, suggesting a disruption of ethylene signalling in the mutants. However, only atmyb44 incurred an abrogation in induced EIN2 expression, suggesting a close relationship between AtMYB44 and EIN2.

  16. Transcriptional characteristics and differences in Arabidopsis stigmatic papilla cells pre- and post-pollination.

    Science.gov (United States)

    Matsuda, Tomoki; Matsushima, Mai; Nabemoto, Moe; Osaka, Masaaki; Sakazono, Satomi; Masuko-Suzuki, Hiromi; Takahashi, Hirokazu; Nakazono, Mikio; Iwano, Megumi; Takayama, Seiji; Shimizu, Kentaro K; Okumura, Katsuzumi; Suzuki, Go; Watanabe, Masao; Suwabe, Keita

    2015-04-01

    Pollination is an important early step in sexual plant reproduction. In Arabidopsis thaliana, sequential pollination events, from pollen adhesion onto the stigma surface to pollen tube germination and elongation, occur on the stigmatic papilla cells. Following successful completion of these events, the pollen tube penetrates the stigma and finally fertilizes a female gametophyte. The pollination events are thought to be initiated and regulated by interactions between papilla cells and pollen. Here, we report the characterization of gene expression profiles of unpollinated (UP), compatible pollinated (CP) and incompatible pollinated (IP) papilla cells in A. thaliana. Based on cell type-specific transcriptome analysis from a combination of laser microdissection and RNA sequencing, 15,475, 17,360 and 16,918 genes were identified as expressed in UP, CP and IP papilla cells, respectively, and, of these, 14,392 genes were present in all three data sets. Differentially expressed gene (DEG) analyses identified 147 and 71 genes up-regulated in CP and IP papilla cells, respectively, and 115 and 46 genes down-regulated. Gene Ontology and metabolic pathway analyses revealed that papilla cells play an active role as the female reproductive component in pollination, particularly in information exchange, signal transduction, internal physiological changes and external morphological modification. This study provides fundamental information on the molecular mechanisms involved in pollination in papilla cells, furthering our understanding of the reproductive role of papilla cells.

  17. Microarray Analysis of Transcriptional Responses to Abscisic Acid and Salt Stress in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Yucheng Wang

    2013-05-01

    Full Text Available Abscisic acid (ABA plays a crucial role in plant responses to abiotic stress. To investigate differences in plant responses to salt and ABA stimulus, differences in gene expression in Arabidopsis in response to salt and ABA were compared using an Agilent oligo microarray. A total of 144 and 139 genes were significantly up- and downregulated, respectively, under NaCl stress, while 406 and 381 genes were significantly up- and downregulated, respectively, under ABA stress conditions. In addition, 31 genes were upregulated by both NaCl and ABA stresses, and 23 genes were downregulated by these stressors, suggesting that these genes may play similar roles in plant responses to salt and ABA stress. Gene ontology (GO analysis revealed four subgroups of genes, including genes in the GO categories “Molecular transducer activity”, “Growth”, “Biological adhesion” and “Pigmentation”, which were expressed in response to ABA stress but not NaCl stress. In addition, genes that play specific roles during salt or ABA stress were identified. Our results may help elucidate differences in the response of plants to salt and ABA stress.

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

    Indian Academy of Sciences (India)

    Swadhin Swain; Nidhi Singh; Ashis Kumar Nandi

    2015-03-01

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

  19. Tracking transcription factor mobility and interaction in Arabidopsis roots with fluorescence correlation spectroscopy.

    Science.gov (United States)

    Clark, Natalie M; Hinde, Elizabeth; Winter, Cara M; Fisher, Adam P; Crosti, Giuseppe; Blilou, Ikram; Gratton, Enrico; Benfey, Philip N; Sozzani, Rosangela

    2016-06-11

    To understand complex regulatory processes in multicellular organisms, it is critical to be able to quantitatively analyze protein movement and protein-protein interactions in time and space. During Arabidopsis development, the intercellular movement of SHORTROOT (SHR) and subsequent interaction with its downstream target SCARECROW (SCR) control root patterning and cell fate specification. However, quantitative information about the spatio-temporal dynamics of SHR movement and SHR-SCR interaction is currently unavailable. Here, we quantify parameters including SHR mobility, oligomeric state, and association with SCR using a combination of Fluorescent Correlation Spectroscopy (FCS) techniques. We then incorporate these parameters into a mathematical model of SHR and SCR, which shows that SHR reaches a steady state in minutes, while SCR and the SHR-SCR complex reach a steady-state between 18 and 24 hr. Our model reveals the timing of SHR and SCR dynamics and allows us to understand how protein movement and protein-protein stoichiometry contribute to development.

  20. Arabidopsis transcriptional response to extracellular Ca2þ depletion involves a transient rise in cytosolic Ca2þ

    Institute of Scientific and Technical Information of China (English)

    Zhi Qi

    2015-01-01

    Ecological evidence indicates a worldwide trend of dramatical y decreased soil Ca2þ levels caused by increased acid deposition and massive timber harvesting. Little is known about the genetic and cel ular mechanism of plants’ responses to Ca2þ depletion. In this study, transcriptional profiling analysis helped identify multiple extracel ular Ca2þ ([Ca2þ]ext) depletion‐respon-sive genes in Arabidopsis thaliana L., many of which are involved in response to other environmental stresses. Interestingly, a group of genes encoding putative cytosolic Ca2þ ([Ca2þ]cyt) sensors were significantly upregulated, implying that [Ca2þ]cyt has a role in sensing [Ca2þ]ext depletion. Consistent with this observation, [Ca2þ]ext depletion stimulated a transient rise in [Ca2þ]cyt that was negatively influenced by [Kþ]ext, suggesting the involvement of a membrane potential‐sensitive component. The [Ca2þ]cyt response to [Ca2þ]ext depletion was significantly desensitized after the initial treatment, which is typical of a receptor‐mediated signaling event. The response was insensi-tive to an animal Ca2þ sensor antagonist, but was suppressed by neomycin, an inhibitor of phospholipase C. Gd3þ, an inhibitor of Ca2þ channels, suppressed the [Ca2þ]ext‐triggered rise in [Ca2þ]cyt and downstream changes in gene expression. Taken together, this study demonstrates that [Ca2þ]cyt plays an important role in the putative receptor‐mediated cel ular and transcriptional response to [Ca2þ]ext depletion of plant cel s.

  1. Improvement of enzymatic saccharification yield in Arabidopsis thaliana by ectopic expression of the rice SUB1A-1 transcription factor

    Directory of Open Access Journals (Sweden)

    Lizeth Núñez-López

    2015-03-01

    Full Text Available Saccharification of polysaccharides releases monosaccharides that can be used by ethanol-producing microorganisms in biofuel production. To improve plant biomass as a raw material for saccharification, factors controlling the accumulation and structure of carbohydrates must be identified. Rice SUB1A-1 is a transcription factor that represses the turnover of starch and postpones energy-consuming growth processes under submergence stress. Arabidopsis was employed to test if heterologous expression of SUB1A-1 or SUB1C-1 (a related gene can be used to improve saccharification. Cellulolytic and amylolytic enzymatic treatments confirmed that SUB1A-1 transgenics had better saccharification yield than wild-type (Col-0, mainly from accumulated starch. This improved saccharification yield was developmentally controlled; when compared to Col-0, young transgenic vegetative plants yielded 200–300% more glucose, adult vegetative plants yielded 40–90% more glucose and plants in reproductive stage had no difference in yield. We measured photosynthetic parameters, starch granule microstructure, and transcript abundance of genes involved in starch degradation (SEX4, GWD1, juvenile transition (SPL3-5 and meristematic identity (FUL, SOC1 but found no differences to Col-0, indicating that starch accumulation may be controlled by down-regulation of CONSTANS and FLOWERING LOCUS T by SUB1A-1 as previously reported. SUB1A-1 transgenics also offered less resistance to deformation than wild-type concomitant to up-regulation of AtEXP2 expansin and BGL2 glucan-1,3,-beta-glucosidase. We conclude that heterologous SUB1A-1 expression can improve saccharification yield and softness, two traits needed in bioethanol production.

  2. Interaction of Arabidopsis Trihelix-Domain Transcription Factors VFP3 and VFP5 with Agrobacterium Virulence Protein VirF.

    Directory of Open Access Journals (Sweden)

    Elena García-Cano

    Full Text Available Agrobacterium is a natural genetic engineer of plants that exports several virulence proteins into host cells in order to take advantage of the cell machinery to facilitate transformation and support bacterial growth. One of these effectors is the F-box protein VirF, which presumably uses the host ubiquitin/proteasome system (UPS to uncoat the packaging proteins from the invading bacterial T-DNA. By analogy to several other bacterial effectors, VirF most likely has several functions in the host cell and, therefore, several interacting partners among host proteins. Here we identify one such interactor, an Arabidopsis trihelix-domain transcription factor VFP3, and further show that its very close homolog VFP5 also interacted with VirF. Interestingly, interactions of VirF with either VFP3 or VFP5 did not activate the host UPS, suggesting that VirF might play other UPS-independent roles in bacterial infection. To better understand the potential scope of VFP3 function, we used RNAi to reduce expression of the VFP3 gene. Transcriptome profiling of these VFP3-silenced plants using high-throughput cDNA sequencing (RNA-seq revealed that VFP3 substantially affected plant gene expression; specifically, 1,118 genes representing approximately 5% of all expressed genes were significantly either up- or down-regulated in the VFP3 RNAi line compared to wild-type Col-0 plants. Among the 507 up-regulated genes were genes implicated in the regulation of transcription, protein degradation, calcium signaling, and hormone metabolism, whereas the 611 down-regulated genes included those involved in redox regulation, light reactions of photosynthesis, and metabolism of lipids, amino acids, and cell wall. Overall, this pattern of changes in gene expression is characteristic of plants under stress. Thus, VFP3 likely plays an important role in controlling plant homeostasis.

  3. An SGS3-like protein functions in RNA-directed DNA methylation and transcriptional gene silencing in Arabidopsis

    KAUST Repository

    Zheng, Zhimin

    2010-01-06

    RNA-directed DNA methylation (RdDM) is an important epigenetic mechanism for silencing transgenes and endogenous repetitive sequences such as transposons. The RD29A promoter-driven LUCIFERASE transgene and its corresponding endogenous RD29A gene are hypermethylated and silenced in the Arabidopsis DNA demethylase mutant ros1. By screening for second-site suppressors of ros1, we identified the RDM12 locus. The rdm12 mutation releases the silencing of the RD29A-LUC transgene and the endogenous RD29A gene by reducing the promoter DNA methylation. The rdm12 mutation also reduces DNA methylation at endogenous RdDM target loci, including transposons and other repetitive sequences. In addition, the rdm12 mutation affects the levels of small interfering RNAs (siRNAs) from some of the RdDM target loci. RDM12 encodes a protein with XS and coiled-coil domains, and is similar to SGS3, which is a partner protein of RDR6 and can bind to double-stranded RNAs with a 5′ overhang, and is required for several post-transcriptional gene silencing pathways. Our results show that RDM12 is a component of the RdDM pathway, and suggest that RdDM may involve double-stranded RNAs with a 5′ overhang and the partnering between RDM12 and RDR2. © 2010 Blackwell Publishing Ltd.

  4. Arabidopsis IRE1 catalyses unconventional splicing of bZIP60 mRNA to produce the active transcription factor

    KAUST Repository

    Nagashima, Yukihiro

    2011-07-01

    IRE1 plays an essential role in the endoplasmic reticulum (ER) stress response in yeast and mammals. We found that a double mutant of Arabidopsis IRE1A and IRE1B (ire1a/ire1b) is more sensitive to the ER stress inducer tunicamycin than the wild-type. Transcriptome analysis revealed that genes whose induction was reduced in ire1a/ire1b largely overlapped those in the bzip60 mutant. We observed that the active form of bZIP60 protein detected in the wild-type was missing in ire1a/ire1b. We further demonstrated that bZIP60 mRNA is spliced by ER stress, removing 23 ribonucleotides and therefore causing a frameshift that replaces the C-terminal region of bZIP60 including the transmembrane domain (TMD) with a shorter region without a TMD. This splicing was detected in ire1a and ire1b single mutants, but not in the ire1a/ire1b double mutant. We conclude that IRE1A and IRE1B catalyse unconventional splicing of bZIP60 mRNA to produce the active transcription factor.

  5. Comparative physiology and transcriptional networks underlying the heat shock response in Populus trichocarpa, Arabidopsis thaliana and Glycine max

    Energy Technology Data Exchange (ETDEWEB)

    Weston, David [ORNL; Wullschleger, Stan D [ORNL; Yang, Xiaohan [ORNL; Karve, Abhijit A [ORNL; Gunter, Lee E [ORNL; Jawdy, Sara [ORNL; Allen, Sara M [ORNL

    2011-01-01

    The heat shock response continues to be layered with additional complexity as interactions and crosstalk among heat shock proteins (HSPs), the reactive oxygen network and hormonal signalling are discovered. However, comparative analyses exploring variation in each of these processes among species remain relatively unexplored. In controlled environment experiments, photosynthetic response curves were conducted from 22 to 42 C and indicated that temperature optimum of light-saturated photosynthesis was greater for Glycine max relative to Arabidopsis thaliana or Populus trichocarpa. Transcript profiles were taken at defined states along the temperature response curves, and inferred pathway analysis revealed species-specific variation in the abiotic stress and the minor carbohydrate raffinose/galactinol pathways. A weighted gene co-expression network approach was used to group individual genes into network modules linking biochemical measures of the antioxidant system to leaf-level photosynthesis among P. trichocarpa, G. max and A. thaliana. Network-enabled results revealed an expansion in the G. max HSP17 protein family and divergence in the regulation of the antioxidant and heat shock modules relative to P. trichocarpa and A. thaliana. These results indicate that although the heat shock response is highly conserved, there is considerable species-specific variation in its regulation.

  6. Negative Regulation of Anthocynanin Biosynthesis in Arabidopsis by a miR156-Targeted SPL Transcription Factor

    Energy Technology Data Exchange (ETDEWEB)

    Gou, J.Y.; Liu, C.; Felippes, F. F.; Weigel, D.; Wang, J.-W.

    2011-04-01

    Flavonoids are synthesized through an important metabolic pathway that leads to the production of diverse secondary metabolites, including anthocyanins, flavonols, flavones, and proanthocyanidins. Anthocyanins and flavonols are derived from Phe and share common precursors, dihydroflavonols, which are substrates for both flavonol synthase and dihydroflavonol 4-reductase. In the stems of Arabidopsis thaliana, anthocyanins accumulate in an acropetal manner, with the highest level at the junction between rosette and stem. We show here that this accumulation pattern is under the regulation of miR156-targeted SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPL) genes, which are deeply conserved and known to have important roles in regulating phase change and flowering. Increased miR156 activity promotes accumulation of anthocyanins, whereas reduced miR156 activity results in high levels of flavonols. We further provide evidence that at least one of the miR156 targets, SPL9, negatively regulates anthocyanin accumulation by directly preventing expression of anthocyanin biosynthetic genes through destabilization of a MYB-bHLH-WD40 transcriptional activation complex. Our results reveal a direct link between the transition to flowering and secondary metabolism and provide a potential target for manipulation of anthocyanin and flavonol content in plants.

  7. The Arabidopsis transcription factor ABIG1 relays ABA signaled growth inhibition and drought induced senescence

    Science.gov (United States)

    Liu, Tie; Longhurst, Adam D; Talavera-Rauh, Franklin; Hokin, Samuel A; Barton, M Kathryn

    2016-01-01

    Drought inhibits plant growth and can also induce premature senescence. Here we identify a transcription factor, ABA INSENSITIVE GROWTH 1 (ABIG1) required for abscisic acid (ABA) mediated growth inhibition, but not for stomatal closure. ABIG1 mRNA levels are increased both in response to drought and in response to ABA treatment. When treated with ABA, abig1 mutants remain greener and produce more leaves than comparable wild-type plants. When challenged with drought, abig1 mutants have fewer yellow, senesced leaves than wild-type. Induction of ABIG1 transcription mimics ABA treatment and regulates a set of genes implicated in stress responses. We propose a model in which drought acts through ABA to increase ABIG1 transcription which in turn restricts new shoot growth and promotes leaf senescence. The results have implications for plant breeding: the existence of a mutant that is both ABA resistant and drought resistant points to new strategies for isolating drought resistant genetic varieties. DOI: http://dx.doi.org/10.7554/eLife.13768.001 PMID:27697148

  8. The Arabidopsis bHLH25 and bHLH27 transcription factors contribute to susceptibility to the cyst nematode Heterodera schachtii.

    Science.gov (United States)

    Jin, Jing; Hewezi, Tarek; Baum, Thomas J

    2011-01-01

    Successful cyst nematode parasitism depends on the formation and maintenance of feeding sites (syncytia) in host roots, and these processes are highly regulated by the interaction between the cyst nematode and the host. Using an integrated research approach and the Arabidopsis-Beta vulgaris (sugar beet) cyst nematode (Heterodera schachtii) pathosystem, we have determined that the two Arabidopsis basic helix-loop-helix transcription factors bHLH25 and bHLH27 positively influence cyst nematode parasitism. Promoter studies indicated that as early as 1 day post-inoculation, both transcription factor genes were upregulated in developing syncytia, whereas in non-infected plants, these two promoters were not found to be active in the same cells. By using yeast two-hybrid analyses and bimolecular fluorescence complementation assays, we documented that the two bHLH transcription factors can dimerize in planta. Transgenic Arabidopsis plants overexpressing either one or both of the bHLH genes exhibited altered morphology of roots and shoots, as well as an increased susceptibility to H. schachtii. bhlh25 or bhlh27 single mutants were without strong phenotypes, presumably because of functional redundancies in this gene family. However, the bhlh25 bhlh27 double mutant was less susceptible to H. schachtii, confirming an important conducive role of the co-expression of both transcription factor genes for cyst nematode parasitism. Our results document an example of pathogen-induced ectopic co-expression of two regulatory genes to enhance pathogen success, although these transcription factors apparently do not function in concert in non-infected plants. This is an intriguing biological phenomenon that highlights the complexity of obligate biotrophic plant-pathogen interactions, like those of cyst nematodes.

  9. Transcriptional co-regulation of secondary metabolism enzymes in Arabidopsis: functional and evolutionary implications.

    Science.gov (United States)

    Gachon, Claire M M; Langlois-Meurinne, Mathilde; Henry, Yves; Saindrenan, Patrick

    2005-05-01

    The combined knowledge of the Arabidopsis genome and transcriptome now allows to get an integrated view of the dynamics and evolution of metabolic pathways in plants. We used publicly available sets of microarray data obtained in a wide range of different stress and developmental conditions to investigate the co-expression of genes encoding enzymes of secondary metabolism pathways, in particular indoles, phenylpropanoids, and flavonoids. We performed hierarchical clustering of gene expression profiles and found that major enzymes of each pathway display a clear and robust co-expression throughout all the conditions studied. Moreover, detailed analysis evidenced that some genes display co-regulation in particular physiological conditions only, certainly reflecting their modular recruitment into stress- or developmentally regulated biosynthetic pathways. The combination of these microarray data with sequence analysis allows to draw very precise hypotheses on the function of otherwise uncharacterized genes. To illustrate this approach, we focused our analysis on secondary metabolism glycosyltransferases (UGTs), a multigenic family involved in the conjugation of small molecules to sugars like glucose. We propose that UGT74B1 and UGT74C1 may be involved in aromatic and aliphatic glucosinolates synthesis, respectively. We also suggest that UGT75C1 may function as an anthocyanin-5-O-glucosyltransferase in planta. Therefore, this data-mining approach appears very powerful for the functional prediction of unknown genes, and could be transposed to virtually any other gene family. Finally, we suggest that analysis of expression pattern divergence of duplicated genes also provides some insight into the mechanisms of metabolic pathway evolution.

  10. Protein intrinsic disorder in Arabidopsis NAC transcription factors

    DEFF Research Database (Denmark)

    O'Shea, Charlotte; Jensen, Mikael Kryger; Stender, Emil G.P.;

    2015-01-01

    because of its simple MoRF pattern and its ability to interact with RCD1 (radical-induced cell death 1). Experiments in yeast and thermodynamic characterization suggest that its single MoRF region is sufficient for both transcriptional activation and interaction with RCD1. The remainder of the large...... regulatory domain is unlikely to contribute to the interaction, since the domain and truncations thereof have similar affinities for RCD1, which are also similar for ANAC013-RCD1 interactions. However, different enthalpic and entropic contributions to binding were revealed for ANAC046 and ANAC013, suggestive...

  11. Transcriptional and metabolic insights into the differential physiological responses of arabidopsis to optimal and supraoptimal atmospheric CO2.

    Directory of Open Access Journals (Sweden)

    Fatma Kaplan

    Full Text Available BACKGROUND: In tightly closed human habitats such as space stations, locations near volcano vents and closed culture vessels, atmospheric CO(2 concentration may be 10 to 20 times greater than Earth's current ambient levels. It is known that super-elevated (SE CO(2 (>1,200 µmol mol(-1 induces physiological responses different from that of moderately elevated CO(2 (up to 1,200 µmol mol(-1, but little is known about the molecular responses of plants to supra-optimal [CO(2]. METHODOLOGY/PRINCIPAL FINDINGS: To understand the underlying molecular causes for differential physiological responses, metabolite and transcript profiles were analyzed in aerial tissue of Arabidopsis plants, which were grown under ambient atmospheric CO(2 (400 µmol mol(-1, elevated CO(2 (1,200 µmol mol(-1 and SE CO(2 (4,000 µmol mol(-1, at two developmental stages early and late vegetative stage. Transcript and metabolite profiling revealed very different responses to elevated versus SE [CO(2]. The transcript profiles of SE CO(2 treated plants were closer to that of the control. Development stage had a clear effect on plant molecular response to elevated and SE [CO(2]. Photosynthetic acclimation in terms of down-regulation of photosynthetic gene expression was observed in response to elevated [CO(2], but not that of SE [CO(2] providing the first molecular evidence that there appears to be a fundamental disparity in the way plants respond to elevated and SE [CO(2]. Although starch accumulation was induced by both elevated and SE [CO(2], the increase was less at the late vegetative stage and accompanied by higher soluble sugar content suggesting an increased starch breakdown to meet sink strength resulting from the rapid growth demand. Furthermore, many of the elevated and SE CO(2-responsive genes found in the present study are also regulated by plant hormone and stress. CONCLUSIONS/SIGNIFICANCE: This study provides new insights into plant acclimation to elevated and SE [CO

  12. Regulation of secondary cell wall biosynthesis by poplar R2R3 MYB transcription factor PtrMYB152 in Arabidopsis.

    Science.gov (United States)

    Wang, Shucai; Li, Eryang; Porth, Ilga; Chen, Jin-Gui; Mansfield, Shawn D; Douglas, Carl J

    2014-05-23

    Poplar has 192 annotated R2R3 MYB genes, of which only three have been shown to play a role in the regulation of secondary cell wall formation. Here we report the characterization of PtrMYB152, a poplar homolog of the Arabidopsis R2R3 MYB transcription factor AtMYB43, in the regulation of secondary cell wall biosynthesis. The expression of PtrMYB152 in secondary xylem is about 18 times of that in phloem. When expressed in Arabidopsis under the control of either 35S or PtrCesA8 promoters, PtrMYB152 increased secondary cell wall thickness, which is likely caused by increased lignification. Accordingly, elevated expression of genes encoding sets of enzymes in secondary wall biosynthesis were observed in transgenic plants expressing PtrMYB152. Arabidopsis protoplast transfection assays suggested that PtrMYB152 functions as a transcriptional activator. Taken together, our results suggest that PtrMYB152 may be part of a regulatory network activating expression of discrete sets of secondary cell wall biosynthesis genes.

  13. Regulation of secondary cell wall biosynthesis by poplar R2R3 MYB transcription factor PtrMYB152 in Arabidopsis

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shucai [Northeast Normal Univ., Changchun (China); Univ. of British Columbia, Vancouver, BC (Canada); Li, Eryang [Univ. of British Columbia, Vancouver, BC (Canada); Porth, Ilga [Univ. of British Columbia, Vancouver, BC (Canada); Chen, Jin-Gui [Univ. of British Columbia, Vancouver, BC (Canada); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Mansfield, Shawn D. [Univ. of British Columbia, Vancouver, BC (Canada); Douglas, Carl [Univ. of British Columbia, Vancouver, BC (Canada)

    2014-05-23

    Poplar has 192 annotated R2R3 MYB genes, of which only three have been shown to play a role in the regulation of secondary cell wall formation. Here we report the characterization of PtrMYB152, a poplar homolog of the Arabidopsis R2R3 MYB transcription factor AtMYB43, in the regulation of secondary cell wall biosynthesis. The expression of PtrMYB152 in secondary xylem is about 18 times of that in phloem. When expressed in Arabidopsis under the control of either 35S or PtrCesA8 promoters, PtrMYB152 increased secondary cell wall thickness, which is likely caused by increased lignification. Accordingly, elevated expression of genes encoding sets of enzymes in secondary wall biosynthesis were observed in transgenic plants expressing PtrMYB152. Arabidopsis protoplast transfection assays suggested that PtrMYB152 functions as a transcriptional activator. Taken together, our results suggest that PtrMYB152 may be part of a regulatory network activating expression of discrete sets of secondary cell wall biosynthesis genes.

  14. SEUSS Integrates Gibberellin Signaling with Transcriptional Inputs from the SHR-SCR-SCL3 Module to Regulate Middle Cortex Formation in the Arabidopsis Root.

    Science.gov (United States)

    Gong, Xue; Flores-Vergara, Miguel A; Hong, Jing Han; Chu, Huangwei; Lim, Jun; Franks, Robert G; Liu, Zhongchi; Xu, Jian

    2016-03-01

    A decade of studies on middle cortex (MC) formation in the root endodermis of Arabidopsis (Arabidopsis thaliana) have revealed a complex regulatory network that is orchestrated by several GRAS family transcription factors, including SHORT-ROOT (SHR), SCARECROW (SCR), and SCARECROW-LIKE3 (SCL3). However, how their functions are regulated remains obscure. Here we show that mutations in the SEUSS (SEU) gene led to a higher frequency of MC formation. seu mutants had strongly reduced expression of SHR, SCR, and SCL3, suggesting that SEU positively regulates these genes. Our results further indicate that SEU physically associates with upstream regulatory sequences of SHR, SCR, and SCL3; and that SEU has distinct genetic interactions with these genes in the control of MC formation, with SCL3 being epistatic to SEU. Similar to SCL3, SEU was repressed by the phytohormone GA and induced by the GA biosynthesis inhibitor paclobutrazol, suggesting that SEU acts downstream of GA signaling to regulate MC formation. Consistently, we found that SEU mediates the regulation of SCL3 by GA signaling. Together, our study identifies SEU as a new critical player that integrates GA signaling with transcriptional inputs from the SHR-SCR-SCL3 module to regulate MC formation in the Arabidopsis root.

  15. The Solanum lycopersicum Zinc Finger2 cysteine-2/histidine-2 repressor-like transcription factor regulates development and tolerance to salinity in tomato and Arabidopsis.

    Science.gov (United States)

    Hichri, Imène; Muhovski, Yordan; Žižkova, Eva; Dobrev, Petre I; Franco-Zorrilla, Jose Manuel; Solano, Roberto; Lopez-Vidriero, Irene; Motyka, Vaclav; Lutts, Stanley

    2014-04-01

    The zinc finger superfamily includes transcription factors that regulate multiple aspects of plant development and were recently shown to regulate abiotic stress tolerance. Cultivated tomato (Solanum lycopersicum Zinc Finger2 [SIZF2]) is a cysteine-2/histidine-2-type zinc finger transcription factor bearing an ERF-associated amphiphilic repression domain and binding to the ACGTCAGTG sequence containing two AGT core motifs. SlZF2 is ubiquitously expressed during plant development, and is rapidly induced by sodium chloride, drought, and potassium chloride treatments. Its ectopic expression in Arabidopsis (Arabidopsis thaliana) and tomato impaired development and influenced leaf and flower shape, while causing a general stress visible by anthocyanin and malonyldialdehyde accumulation. SlZF2 enhanced salt sensitivity in Arabidopsis, whereas SlZF2 delayed senescence and improved tomato salt tolerance, particularly by maintaining photosynthesis and increasing polyamine biosynthesis, in salt-treated hydroponic cultures (125 mm sodium chloride, 20 d). SlZF2 may be involved in abscisic acid (ABA) biosynthesis/signaling, because SlZF2 is rapidly induced by ABA treatment and 35S::SlZF2 tomatoes accumulate more ABA than wild-type plants. Transcriptome analysis of 35S::SlZF2 revealed that SlZF2 both increased and reduced expression of a comparable number of genes involved in various physiological processes such as photosynthesis, polyamine biosynthesis, and hormone (notably ABA) biosynthesis/signaling. Involvement of these different metabolic pathways in salt stress tolerance is discussed.

  16. Promotion of growth by elevated carbon dioxide is coordinated through a flexible transcriptional network in Arabidopsis.

    Science.gov (United States)

    Ribeiro, Dimas M; Mueller-Roeber, Bernd; Schippers, Jos H M

    2013-03-01

    Although gibberellins (GAs) promote many developmental responses in plants, little is known about how the hormone interacts with environmental signals at the molecular level for regulating plant growth. Recently, we have demonstrated that inhibition of growth by the GA biosynthesis inhibitor paclobutrazol (PAC) at ambient [CO₂] (350 µmol CO₂ mol(-1)) is reverted by elevated [CO₂] (750 μmol CO₂ mol(-1)). Our finding points to an important role of elevated [CO₂] as a signal allowing higher growth rates of low-GA plants. GA promotes plant growth via a complex transcriptional network that integrates multiple signaling pathways. Herein, we discuss how elevated [CO₂] stimulates biomass accumulation in a GA-independent manner by regulating the expression of growth-related genes.

  17. Overexpression of the poplar NF-YB7 transcription factor confers drought tolerance and improves water-use efficiency in Arabidopsis.

    Science.gov (United States)

    Han, Xiao; Tang, Sha; An, Yi; Zheng, Dong-Chao; Xia, Xin-Li; Yin, Wei-Lun

    2013-11-01

    Water deficit is a serious environmental factor limiting the growth and productivity of plants worldwide. Improvement of drought tolerance and efficient water use are significant strategies to overcome this dilemma. In this study, a drought-responsive transcription factor, nuclear factor Y subunit B 7 (PdNF-YB7), induced by osmotic stress (PEG6000) and abscisic acid, was isolated from fast-growing poplar clone NE-19 [Populus nigra × (Populus deltoides × Populus nigra)]. Ectopic overexpression of PdNF-YB7 (oxPdB7) in Arabidopsis enhanced drought tolerance and whole-plant and instantaneous leaf water-use efficiency (WUE, the ratio of biomass produced to water consumed). Overexpressing lines had an increase in germination rate and root length and decrease in water loss and displayed higher photosynthetic rate, instantaneous leaf WUE, and leaf water potential to exhibit enhanced drought tolerance under water scarcity. Additionally, overexpression of PdNF-YB7 in Arabidopsis improved whole-plant WUE by increasing carbon assimilation and reducing transpiration with water abundance. These drought-tolerant, higher WUE transgenic Arabidopsis had earlier seedling establishment and higher biomass than controls under normal and drought conditions. In contrast, Arabidopsis mutant nf-yb3 was more sensitive to drought stress with lower WUE. However, complementation analysis indicated that complementary lines (nf-yb3/PdB7) had almost the same drought response and WUE as wild-type Col-0. Taken together, these results suggest that PdNF-YB7 positively confers drought tolerance and improves WUE in Arabidopsis; thus it could potentially be used in breeding drought-tolerant plants with increased production even under water deficiency.

  18. A compatible interaction of Alternaria brassicicola with Arabidopsis thaliana ecotype DiG: evidence for a specific transcriptional signature

    Directory of Open Access Journals (Sweden)

    Gepstein Shimon

    2009-03-01

    Full Text Available Abstract Background The interaction of Arabidopsis with Alternaria brassicicola provides a model for disease caused by necrotrophs, but a drawback has been the lack of a compatible pathosystem. Infection of most ecotypes, including the widely-studied line Col-0, with this pathogen generally leads to a lesion that does not expand beyond the inoculated area. This study examines an ecotype, Dijon G (DiG, which is considered sensitive to A. brassicicola. Results We show that the interaction has the characteristics of a compatible one, with expanding rather than limited lesions. To ask whether DiG is merely more sensitive to the pathogen or, rather, interacts in distinct manner, we identified genes whose regulation differs between Col-0 and DiG challenged with A. brassicicola. Suppression subtractive hybridization was used to identify differentially expressed genes, and their expression was verified using semi-quantitative PCR. We also tested a set of known defense-related genes for differential regulation in the two plant-pathogen interactions. Several known pathogenesis-related (PR genes are up-regulated in both interactions. PR1, and a monooxygenase gene identified in this study, MO1, are preferentially up-regulated in the compatible interaction. In contrast, GLIP1, which encodes a secreted lipase, and DIOX1, a pathogen-response related dioxygenase, are preferentially up-regulated in the incompatible interaction. Conclusion The results show that DiG is not only more susceptible, but demonstrate that its interaction with A. brassicicola has a specific transcriptional signature.

  19. High REDOX RESPONSIVE TRANSCRIPTION FACTOR1 Levels Result in Accumulation of Reactive Oxygen Species in Arabidopsis thaliana Shoots and Roots.

    Science.gov (United States)

    Matsuo, Mitsuhiro; Johnson, Joy Michal; Hieno, Ayaka; Tokizawa, Mutsutomo; Nomoto, Mika; Tada, Yasuomi; Godfrey, Rinesh; Obokata, Junichi; Sherameti, Irena; Yamamoto, Yoshiharu Y; Böhmer, Frank-D; Oelmüller, Ralf

    2015-08-01

    Redox Responsive Transcription Factor1 (RRTF1) in Arabidopsis is rapidly and transiently upregulated by H2O2, as well as biotic- and abiotic-induced redox signals. RRTF1 is highly conserved in angiosperms, but its physiological role remains elusive. Here we show that inactivation of RRTF1 restricts and overexpression promotes reactive oxygen species (ROS) accumulation in response to stress. Transgenic lines overexpressing RRTF1 are impaired in root and shoot development, light sensitive, and susceptible to Alternaria brassicae infection. These symptoms are diminished by the beneficial root endophyte Piriformospora indica, which reduces ROS accumulation locally in roots and systemically in shoots, and by antioxidants and ROS inhibitors that scavenge ROS. More than 800 genes were detected in mature leaves and seedlings of transgenic lines overexpressing RRTF1; ∼ 40% of them have stress-, redox-, ROS-regulated-, ROS-scavenging-, defense-, cell death- and senescence-related functions. Bioinformatic analyses and in vitro DNA binding assays demonstrate that RRTF1 binds to GCC-box-like sequences in the promoter of RRTF1-responsive genes. Upregulation of RRTF1 by stress stimuli and H2O2 requires WRKY18/40/60. RRTF1 is co-regulated with the phylogenetically related RAP2.6, which contains a GCC-box-like sequence in its promoter, but transgenic lines overexpressing RAP2.6 do not accumulate higher ROS levels. RRTF1 also stimulates systemic ROS accumulation in distal non-stressed leaves. We conclude that the elevated levels of the highly conserved RRTF1 induce ROS accumulation in response to ROS and ROS-producing abiotic and biotic stress signals.

  20. Arabidopsis sigma factor binding proteins are activators of the WRKY33 transcription factor in plant defense.

    Science.gov (United States)

    Lai, Zhibing; Li, Ying; Wang, Fei; Cheng, Yuan; Fan, Baofang; Yu, Jing-Quan; Chen, Zhixiang

    2011-10-01

    Necrotrophic pathogens are important plant pathogens that cause many devastating plant diseases. Despite their impact, our understanding of the plant defense response to necrotrophic pathogens is limited. The WRKY33 transcription factor is important for plant resistance to necrotrophic pathogens; therefore, elucidation of its functions will enhance our understanding of plant immunity to necrotrophic pathogens. Here, we report the identification of two WRKY33-interacting proteins, nuclear-encoded SIGMA FACTOR BINDING PROTEIN1 (SIB1) and SIB2, which also interact with plastid-encoded plastid RNA polymerase SIGMA FACTOR1. Both SIB1 and SIB2 contain an N-terminal chloroplast targeting signal and a putative nuclear localization signal, suggesting that they are dual targeted. Bimolecular fluorescence complementation indicates that WRKY33 interacts with SIBs in the nucleus of plant cells. Both SIB1 and SIB2 contain a short VQ motif that is important for interaction with WRKY33. The two VQ motif-containing proteins recognize the C-terminal WRKY domain and stimulate the DNA binding activity of WRKY33. Like WRKY33, both SIB1 and SIB2 are rapidly and strongly induced by the necrotrophic pathogen Botrytis cinerea. Resistance to B. cinerea is compromised in the sib1 and sib2 mutants but enhanced in SIB1-overexpressing transgenic plants. These results suggest that dual-targeted SIB1 and SIB2 function as activators of WRKY33 in plant defense against necrotrophic pathogens.

  1. The Arabidopsis thaliana TCP transcription factors: A broadening horizon beyond development.

    Science.gov (United States)

    Li, Shutian

    2015-01-01

    The TCP family of transcription factors is named after the first 4 characterized members, namely TEOSINTE BRANCHED1 (TB1) from maize (Zea mays), CYCLOIDEA (CYC) from snapdragon (Antirrhinum majus), as well as PROLIFERATING CELL NUCLEAR ANTIGEN FACTOR1 (PCF1) and PCF2 from rice (Oryza sativa). Phylogenic analysis of this plant-specific protein family unveils a conserved bHLH-containing DNA-binding motif known as the TCP domain. In accordance with the structure of this shared domain, TCP proteins are grouped into class I (TCP-P) and class II (TCP-C), which are suggested to antagonistically modulate plant growth and development via competitively binding similar cis-regulatory modules called site II elements. Over the last decades, TCPs across the plant kingdom have been demonstrated to control a plethora of plant processes. Notably, TCPs also regulate plant development and defense responses via stimulating the biosynthetic pathways of bioactive metabolites, such as brassinosteroid (BR), jasmonic acid (JA) and flavonoids. Besides, mutagenesis analysis coupled with biochemical experiments identifies several crucial amino acids located within the TCP domain, which confer the redox sensitivity of class I TCPs and determine the distinct DNA-binding properties of TCPs. In this review, developmental functions of TCPs in various biological pathways are briefly described with an emphasis on their involvement in the synthesis of bioactive substances. Furthermore, novel biochemical aspects of TCPs with respect to redox regulation and DNA-binding preferences are elaborated. In addition, the unexpected participation of TCPs in effector-triggered immunity (ETI) and defense against insects indicates that the widely recognized developmental regulators are capable of fine-tuning defense signaling and thereby enable plants to evade deleterious developmental phenotypes. Altogether, these recent impressive breakthroughs remarkably advance our understanding as to how TCPs integrate

  2. Efficient use of artificial micro-RNA to downregulate the expression of genes at the post-transcriptional level in Arabidopsis thaliana.

    Science.gov (United States)

    Ud-Din, A; Rauf, M; Ghafoor, S; Khattak, M N K; Hameed, M W; Shah, H; Jan, S; Muhammad, K; Rehman, A; Inamullah

    2016-04-07

    Micro-RNAs are cellular components regulating gene expression at the post-transcription level. In the present study, artificial micro-RNAs were used to decrease the transcript level of two genes, AtExpA8 (encoding an expansin) and AHL25 (encoding an AT-hook motif nuclear localized protein) in Arabidopsis thaliana. The backbone of the Arabidopsis endogenous MIR319a micro-RNA was used in a site-directed mutagenesis approach for the generation of artificial micro-RNAs targeting two genes. The recombinant cassettes were expressed under the control of the CaMV 35S promoter in individual A. thaliana plants. Transgenic lines of the third generation were tested by isolating total RNA and by subsequent cDNA synthesis using oligo-dT18 primers and mRNAs as templates. The expression of the two target genes was checked through quantitative real-time polymerase chain reaction to confirm reduced transcript levels for AtExpA8 and AHL25. Downregulation of AtExpA8 resulted in the formation of short hypocotyls compared with those of the wild-type control in response to low pH and high salt concentration. This technology could be used to prevent the expression of exogenous and invading genes posing a threat to the normal cellular physiology of the host plant.

  3. Iron and FER-LIKE IRON DEFICIENCY-INDUCED TRANSCRIPTION FACTOR-dependent regulation of proteins and genes in Arabidopsis thaliana roots.

    Science.gov (United States)

    Mai, Hans-Jörg; Lindermayr, Christian; von Toerne, Christine; Fink-Straube, Claudia; Durner, Jörg; Bauer, Petra

    2015-09-01

    Iron is an essential micronutrient for plants, and iron deficiency requires a variety of physiological adaptations. FIT (FER-LIKE IRON DEFICIENCY-INDUCED TRANSCRIPTION FACTOR) is essential for the regulation of iron uptake in Arabidopsis thaliana roots. FIT is transcriptionally as well as posttranscriptionally regulated in response to iron supply. To investigate to which extent posttranscriptional regulation upon iron deficiency applies to proteins and to determine the dependency on FIT, we performed a parallel proteomic and transcriptomic study with wild-type, a fit knock-out mutant, and a FIT overexpressing Arabidopsis line. Among 92 proteins differentially regulated by iron and/or FIT, we identified 30 proteins, which displayed differential regulation at the transcriptional level. Eleven protein spots were regulated in at least one of the data points even contrary to the respective genes dependent on FIT. We found ten proteins in at least two forms. The analysis of functional classification showed enriched GO terms among the posttranscriptionally regulated genes and of proteins, that were downregulated or absent in the fit knock-out mutant. Taken together, we provide evidence for iron and FIT-dependent posttranscriptional regulation in iron homeostasis in A. thaliana.

  4. Arabidopsis WRKY6 Transcription Factor Acts as a Positive Regulator of Abscisic Acid Signaling during Seed Germination and Early Seedling Development.

    Science.gov (United States)

    Huang, Yun; Feng, Cui-Zhu; Ye, Qing; Wu, Wei-Hua; Chen, Yi-Fang

    2016-02-01

    The phytohormone abscisic acid (ABA) plays important roles during seed germination and early seedling development. Here, we characterized the function of the Arabidopsis WRKY6 transcription factor in ABA signaling. The transcript of WRKY6 was repressed during seed germination and early seedling development, and induced by exogenous ABA. The wrky6-1 and wrky6-2 mutants were ABA insensitive, whereas WRKY6-overexpressing lines showed ABA-hypersensitive phenotypes during seed germination and early seedling development. The expression of RAV1 was suppressed in the WRKY6-overexpressing lines and elevated in the wrky6 mutants, and the expression of ABI3, ABI4, and ABI5, which was directly down-regulated by RAV1, was enhanced in the WRKY6-overexpressing lines and repressed in the wrky6 mutants. Electrophoretic mobility shift and chromatin immunoprecipitation assays showed that WRKY6 could bind to the RAV1 promoter in vitro and in vivo. Overexpression of RAV1 in WRKY6-overexpressing lines abolished their ABA-hypersensitive phenotypes, and the rav1 wrky6-2 double mutant showed an ABA-hypersensitive phenotype, similar to rav1 mutant. Together, the results demonstrated that the Arabidopsis WRKY6 transcription factor played important roles in ABA signaling by directly down-regulating RAV1 expression.

  5. Zinc-Finger Transcription Factor ZAT6 Positively Regulates Cadmium Tolerance through the Glutathione-Dependent Pathway in Arabidopsis1[OPEN

    Science.gov (United States)

    Chen, Jian; Yan, Xingxing; Liu, Yunlei; Wang, Ren; Fan, Tingting; Ren, Yongbing; Tang, Xiaofeng; Xiao, Fangming

    2016-01-01

    Cadmium (Cd) is an environmental pollutant with high toxicity to animals and plants. It has been established that the glutathione (GSH)-dependent phytochelatin (PC) synthesis pathway is one of the most important mechanisms contributing to Cd accumulation and tolerance in plants. However, the transcription factors involved in regulating GSH-dependent PC synthesis pathway remain largely unknown. Here, we identified an Arabidopsis (Arabidopsis thaliana) Cd-resistant mutant xcd2-D (XVE system-induced cadmium-tolerance2) using a forward genetics approach. The mutant gene underlying xcd2-D mutation was revealed to encode a known zinc-finger transcription factor, ZAT6. Transgenic plants overexpressing ZAT6 showed significant increase of Cd tolerance, whereas loss of function of ZAT6 led to decreased Cd tolerance. Increased Cd accumulation and tolerance in ZAT6-overexpressing lines was GSH dependent and associated with Cd-activated synthesis of PC, which was correlated with coordinated activation of PC-synthesis related gene expression. By contrast, loss of function of ZAT6 reduced Cd accumulation and tolerance, which was accompanied by abolished PC synthesis and gene expression. Further analysis revealed that ZAT6 positively regulates the transcription of GSH1, GSH2, PCS1, and PCS2, but ZAT6 is capable of specifically binding to GSH1 promoter in vivo. Consistently, overexpression of GSH1 has been shown to restore Cd sensitivity in the zat6-1 mutant, suggesting that GSH1 is a key target of ZAT6. Taken together, our data provide evidence that ZAT6 coordinately activates PC synthesis-related gene expression and directly targets GSH1 to positively regulate Cd accumulation and tolerance in Arabidopsis. PMID:26983992

  6. ZINC FINGER OF ARABIDOPSIS THALIANA12 (ZAT12) Interacts with FER-LIKE IRON DEFICIENCY-INDUCED TRANSCRIPTION FACTOR (FIT) Linking Iron Deficiency and Oxidative Stress Responses.

    Science.gov (United States)

    Le, Cham Thi Tuyet; Brumbarova, Tzvetina; Ivanov, Rumen; Stoof, Claudia; Weber, Eva; Mohrbacher, Julia; Fink-Straube, Claudia; Bauer, Petra

    2016-01-01

    Plants grown under iron (Fe)-deficient conditions induce a set of genes that enhance the efficiency of Fe uptake by the roots. In Arabidopsis (Arabidopsis thaliana), the central regulator of this response is the basic helix-loop-helix transcription factor FER-LIKE IRON DEFICIENCY-INDUCED TRANSCRIPTION FACTOR (FIT). FIT activity is regulated by protein-protein interactions, which also serve to integrate external signals that stimulate and possibly inhibit Fe uptake. In the search of signaling components regulating FIT function, we identified ZINC FINGER OF ARABIDOPSIS THALIANA12 (ZAT12), an abiotic stress-induced transcription factor. ZAT12 interacted with FIT, dependent on the presence of the ethylene-responsive element-binding factor-associated amphiphilic repression motif. ZAT12 protein was found expressed in the root early differentiation zone, where its abundance was modulated in a root layer-specific manner. In the absence of ZAT12, FIT expression was upregulated, suggesting a negative effect of ZAT12 on Fe uptake. Consistently, zat12 loss-of-function mutants had higher Fe content than the wild type at sufficient Fe. We found that under Fe deficiency, hydrogen peroxide (H2O2) levels were enhanced in a FIT-dependent manner. FIT protein, in turn, was stabilized by H2O2 but only in the presence of ZAT12, showing that H2O2 serves as a signal for Fe deficiency responses. We propose that oxidative stress-induced ZAT12 functions as a negative regulator of Fe acquisition. A model where H2O2 mediates the negative regulation of plant responses to prolonged stress might be applicable to a variety of stress conditions.

  7. Studies on Differential Nuclear Translocation Mechanism and Assembly of the Three Subunits of the Arabidopsis thaliana Transcription Factor NF-Y

    Institute of Scientific and Technical Information of China (English)

    Dieter Hackenberg; Yanfang Wu; Andrea Voigt; Robert Adams; Peter Schramm; Bernhard Grimm

    2012-01-01

    The eukaryotic transcription factor NF-Y consists of three subunits(A,B,and C),which are encoded in Arabidopsis thaliana in multigene families consisting of 10,13,and 13 genes,respectively.In principle,all potential combinations of the subunits are possible for the assembly of the heterotrimeric complex.We aimed at assessing the probability of each subunit to participate in the assembly of NF-Y.The evaluation of physical interactions among all members of the NF-Y subunit families indicate a strong requirement for NF-YB/NF-YC heterodimerization before the entire complex can be accomplished.By means of a modified yeast two-hybrid system assembly of all three subunits to a heterotrimeric complex was demonstrated.Using GFP fusion constructs,NF-YA and NF-YC localization in the nucleus was demonstrated,while NFYB is solely imported into the nucleus as a NF-YC-associated heterodimer NF-YC.This piggyback transport of the two Arabidopsis subunits differs from the import of the NF-Y heterotrimer of heterotrophic organisms.Based on a peptide structure model of the histone-fold-motifs,disulfide bonding among intramolecular conserved cysteine residues of NF-YB,which is responsible for the redox-regulated assembly of NF-YB and NF-YC in human and Aspergillus nidulans,can be excluded for Arabidopsis NF-YB.

  8. The Arabidopsis SET-domain protein ASHR3 is involved in stamen development and interacts with the bHLH transcription factor ABORTED MICROSPORES (AMS).

    Science.gov (United States)

    Thorstensen, Tage; Grini, Paul E; Mercy, Inderjit S; Alm, Vibeke; Erdal, Sigrid; Aasland, Rein; Aalen, Reidunn B

    2008-01-01

    The Arabidopsis thaliana genome contains more than 30 genes encoding SET-domain proteins that are thought to be epigenetic regulators of gene expression and chromatin structure. SET-domain proteins can be divided into subgroups, and members of the Polycomb group (PcG) and trithorax group (trxG) have been shown to be important regulators of development. Both in animals and plants some of these proteins are components of multimeric protein complexes. Here, we have analyzed the Arabidopsis trxG protein ASHR3 which has a SET domain and pre- and post-SET domains similar to that of Ash1 in Drosophila. In addition to the SET domain, a divergent PHD finger is found in the N-terminus of the ASHR3 protein. As expected from SET-domain proteins involved in transcriptional activation, ASHR3 (coupled to GFP) localizes to euchromatin. A yeast two-hybrid screening revealed that the ASHR3 protein interacts with the putative basic helix-loop-helix (bHLH) transcription factor ABORTED MICROSPORES (AMS), which is involved in anther and stamen development in Arabidopsis. Deletion mapping indicated that both the PHD finger and the SET domain mediate the interaction between the two proteins. Overexpression of ASHR3 led in general to growth arrest, and specifically to degenerated anthers and male sterility. Expression analyses demonstrated that ASHR3 like AMS is expressed in the anther and in stamen filaments. We therefore propose that AMS can target ASHR3 to chromatin and regulate genes involved in stamen development and function.

  9. Transcriptional responses to polycyclic aromatic hydrocarbon-induced stress in Arabidopsis thaliana reveal the involvement of hormone and defense signaling pathways

    Directory of Open Access Journals (Sweden)

    Colón-Carmona Adán

    2010-04-01

    Full Text Available Abstract Background Polycyclic aromatic hydrocarbons (PAHs are toxic, widely-distributed, environmentally persistent, and carcinogenic byproducts of carbon-based fuel combustion. Previously, plant studies have shown that PAHs induce oxidative stress, reduce growth, and cause leaf deformation as well as tissue necrosis. To understand the transcriptional changes that occur during these processes, we performed microarray experiments on Arabidopsis thaliana L. under phenanthrene treatment, and compared the results to published Arabidopsis microarray data representing a variety of stress and hormone treatments. In addition, to probe hormonal aspects of PAH stress, we assayed transgenic ethylene-inducible reporter plants as well as ethylene pathway mutants under phenanthrene treatment. Results Microarray results revealed numerous perturbations in signaling and metabolic pathways that regulate reactive oxygen species (ROS and responses related to pathogen defense. A number of glutathione S-transferases that may tag xenobiotics for transport to the vacuole were upregulated. Comparative microarray analyses indicated that the phenanthrene response was closely related to other ROS conditions, including pathogen defense conditions. The ethylene-inducible transgenic reporters were activated by phenanthrene. Mutant experiments showed that PAH inhibits growth through an ethylene-independent pathway, as PAH-treated ethylene-insensitive etr1-4 mutants exhibited a greater growth reduction than WT. Further, phenanthrene-treated, constitutive ethylene signaling mutants had longer roots than the untreated control plants, indicating that the PAH inhibits parts of the ethylene signaling pathway. Conclusions This study identified major physiological systems that participate in the PAH-induced stress response in Arabidopsis. At the transcriptional level, the results identify specific gene targets that will be valuable in finding lead compounds and engineering increased

  10. Transcriptional regulation of heat shock proteins and ascorbate peroxidase by CtHsfA2b from African bermudagrass conferring heat tolerance in Arabidopsis

    Science.gov (United States)

    Wang, Xiuyun; Huang, Wanlu; Yang, Zhimin; Liu, Jun; Huang, Bingru

    2016-01-01

    Heat stress transcription factor A2s (HsfA2s) are key regulators in plant response to high temperature. Our objectives were to isolate an HsfA2 gene (CtHsfA2b) from a warm-season grass species, African bermudagrass (Cynodon transvaalensis Burtt-Davy), and to determine the physiological functions and transcriptional regulation of HsfA2 for improving heat tolerance. Gene expression analysis revealed that CtHsfA2b was heat-inducible and exhibited rapid response to increasing temperature. Ectopic expression of CtHsfA2b improved heat tolerance in Arabidopsis and restored heat-sensitive defects of Arabidopsis hsfa2 mutant, which was demonstrated by higher survival rate and photosynthetic parameters, and lower electrolyte leakage in transgenic plants compared to the WT or hsfa2 mutant. CtHsfA2b transgenic plants showed elevated transcriptional regulation of several downstream genes, including those encoding ascorbate peroxidase (AtApx2) and heat shock proteins [AtHsp18.1-CI, AtHsp22.0-ER, AtHsp25.3-P and AtHsp26.5-P(r), AtHsp70b and AtHsp101-3]. CtHsfA2b was found to bind to the heat shock element (HSE) on the promoter of AtApx2 and enhanced transcriptional activity of AtApx2. These results suggested that CtHsfA2b could play positive roles in heat protection by up-regulating antioxidant defense and chaperoning mechanisms. CtHsfA2b has the potential to be used as a candidate gene to genetically modify cool-season species for improving heat tolerance. PMID:27320381

  11. Identification of the minimal repression domain of SUPERMAN shows that the DLELRL hexapeptide is both necessary and sufficient for repression of transcription in Arabidopsis.

    Science.gov (United States)

    Hiratsu, Keiichiro; Mitsuda, Nobutaka; Matsui, Kyoko; Ohme-Takagi, Masaru

    2004-08-13

    We reported previously that the carboxy-terminal 30 amino acids of SUPERMAN (SUPRD) function as a repression domain in Arabidopsis. In this study, we identified the peptide sequences in SUPRD that is both necessary and sufficient for repression of transcription. To our surprise, the hexapeptide DLELRL was sufficient, by itself, to confer the ability to repress transcription on a DNA-binding domain. A database search revealed that there are 32 TFIIIA-type zinc finger proteins in the Arabidopsis genome that contain a hexapeptide sequence similar or identical to that of DLELRL. These peptides acted as repression domains, suggesting that these zinc finger proteins might function as active repressors. Further mutational analysis within DLELRL revealed that an amphiphilic motif composed of six amino acids (XLxLXL) with preferences at the first and fifth positions is necessary and sufficient for strong repression. An assay of positional effects suggested that GAL4DB-DLELRL might function as a short-range repressor. A possible mechanism of the DLELRL-mediated repression is discussed.

  12. Improvement of drought and salt tolerance in Arabidopsis and Lotus corniculatus by overexpression of a novel DREB transcription factor from Populus euphratica.

    Science.gov (United States)

    Zhou, Mei-Liang; Ma, Jiang-Tao; Zhao, Yang-Min; Wei, Ya-Hui; Tang, Yi-Xiong; Wu, Yan-Min

    2012-09-10

    A novel DREB (dehydration-responsive element binding) gene, designated PeDREB2a, was isolated from the desert-grown tree, Populus euphratica Oliv. PeDREB2a is classified into the A-5 group of DREB subfamily based on multiple sequence alignment and phylogenetic characterization. Using semi-quantitative RT-PCR, we found that the PeDREB2a was greatly induced by drought, NaCl, low temperature, 1-naphthaleneacetic acid (NAA), 6-benzyl aminopurine (6-BA) and gibberellic acid (GA3) treatments in P. euphratica seedling. Yeast transactivity assay demonstrated that PeDREB2a gene encodes a transcription activator. Overexpression of PeDREB2a under the stress-inducible rd29A promotor in transgenic Arabidopsis and Lotus corniculatus forage plants resulted in enhanced tolerance to salt and drought stresses. The PeDREB2a overexpressing Arabidopsis lines showed higher root length and plant height and had elevated levels of soluble sugars and lower levels of malondialdehyde under stress conditions compared to control plants. The results revealed that PeDREB2a play an essential role as a DREB transcription factor in regulation of stress-responsive signaling in P. euphratica.

  13. Application of HB17, an Arabidopsis class II homeodomain-leucine zipper transcription factor, to regulate chloroplast number and photosynthetic capacity.

    Science.gov (United States)

    Hymus, Graham J; Cai, Suqin; Kohl, Elizabeth A; Holtan, Hans E; Marion, Colleen M; Tiwari, Shiv; Maszle, Don R; Lundgren, Marjorie R; Hong, Melissa C; Channa, Namitha; Loida, Paul; Thompson, Rebecca; Taylor, J Philip; Rice, Elena; Repetti, Peter P; Ratcliffe, Oliver J; Reuber, T Lynne; Creelman, Robert A

    2013-11-01

    Transcription factors are proposed as suitable targets for the control of traits such as yield or food quality in plants. This study reports the results of a functional genomics research effort that identified ATHB17, a transcription factor from the homeodomain-leucine zipper class II family, as a novel target for the enhancement of photosynthetic capacity. It was shown that ATHB17 is expressed natively in the root quiescent centre (QC) from Arabidopsis embryos and seedlings. Analysis of the functional composition of genes differentially expressed in the QC from a knockout mutant (athb17-1) compared with its wild-type sibling revealed the over-representation of genes involved in auxin stimulus, embryo development, axis polarity specification, and plastid-related processes. While no other phenotypes were observed in athb17-1 plants, overexpression of ATHB17 produced a number of phenotypes in Arabidopsis including enhanced chlorophyll content. Image analysis of isolated mesophyll cells of 35S::ATHB17 lines revealed an increase in the number of chloroplasts per unit cell size, which is probably due to an increase in the number of proplastids per meristematic cell. Leaf physiological measurements provided evidence of improved photosynthetic capacity in 35S::ATHB17 lines on a per unit leaf area basis. Estimates of the capacity for ribulose-1,5-bisphosphate-saturated and -limited photosynthesis were significantly higher in 35S::ATHB17 lines.

  14. Systematic analysis of phloem-feeding insect-induced transcriptional reprogramming in Arabidopsis highlights common features and reveals distinct responses to specialist and generalist insects.

    Science.gov (United States)

    Foyer, Christine H; Verrall, Susan R; Hancock, Robert D

    2015-02-01

    Phloem-feeding insects (PFIs), of which aphids are the largest group, are major agricultural pests causing extensive damage to crop plants. In contrast to chewing insects, the nature of the plant response to PFIs remains poorly characterized. Scrutiny of the literature concerning transcriptional responses of model and crop plant species to PFIs reveals surprisingly little consensus with respect to the transcripts showing altered abundance following infestation. Nevertheless, core features of the transcriptional response to PFIs can be defined in Arabidopsis thaliana. This comparison of the PFI-associated transcriptional response observed in A. thaliana infested by the generalists Myzus persicae and Bemisia tabaci with the specialist Brevicoryne brassicae highlights the importance of calcium-dependent and receptor kinase-associated signalling. We discuss these findings within the context of the complex cross-talk between the different hormones regulating basal immune response mechanisms in plants. We identify PFI-responsive genes, highlighting the importance of cell wall-associated kinases in plant-PFI interactions, as well as the significant role of kinases containing the domain of unknown function 26. A common feature of plant-PFI interaction is enhanced abundance of transcripts encoding WRKY transcription factors. However, significant divergence was observed with respect to secondary metabolism dependent upon the insect attacker. Transcripts encoding enzymes and proteins associated with glucosinolate metabolism were decreased following attack by the generalist M. persicae but not by the specialist B. brassicae. This analysis provides a comprehensive overview of the molecular patterns associated with the plant response to PFIs and suggests that plants recognize and respond to perturbations in the cell wall occurring during PFI infestation.

  15. Intercellular communication in Arabidopsis thaliana pollen discovered via AHG3 transcript movement from the vegetative cell to sperm

    Science.gov (United States)

    An Arabidopsis pollen grain (male gametophyte) consists of three cells: the vegetative cell, which forms the pollen tube, and two sperm cells enclosed within the vegetative cell. It is still unclear if there is intercellular communication between the vegetative cell and the sperm cells. Here we show...

  16. The Clock Protein CCA1 and the bZIP Transcription Factor HY5 Physically Interact to Regulate Gene Expression in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Christos Andronis; Simon Barak; Stephen M.Knowles; Shoji Sugano; Elaine M.Tobin

    2008-01-01

    The circadian clock regulates the expression of an array of Arabidopsis genes such as those encoding the LIGHT-HARVESTING CHLOROPHYLL A/B (Lhcb) proteins. We have previously studied the promoters of two of these Arabidopsis genes-Lhcb1*1 and Lhcb1*3-and identified a sequence that binds the clock protein CIRCADIAN CLOCK ASSOCIATED 1 (CCA1). This sequence, designated CCAl-binding site (CBS), is necessary for phytochrome and circadian responsiveness of these genes. In close proximity to this sequence, there exists a G-box core element that has been shown to bind the bZIP transcription factor HY5 in other light-regulated plant promoters. In the present study, we examined the importance of the interaction of transcription factors binding the CBS and the G-box core element in the control of normal circadian rhythmic expression of Lhcb genes. Our results show that HY5 is able to specifically bind the G-box element in the Lhcb promoters and that CCA1 can alter the binding activity of HY5. We further show that CCA1 and HY5 can physically interact and that they can act synergistically on transcription in a yeast reporter gene assay. An absence of HY5 leads to a shorter period of Lhcb1*1 circadian expression but does not affect the circadian expression of CATALASE3 (CAT3), whose promoter lacks a G-box element. Our results suggest that interaction of the HY5 and CCA1 proteins on Lhcb promoters is necessary for normal circadian expression of the Lhcb genes.

  17. 拟南芥B3转录因子基因超家族%Research progress of Arabidopsis B3 transcription factor gene superfamily

    Institute of Scientific and Technical Information of China (English)

    罗光宇; 叶玲飞; 陈信波

    2013-01-01

    B3类转录因子基因组成了植物所特有的B3基因超家族,按照其结构和功能的特征可将其进一步分为LAV(LEAFY COTYLEDON2 [LEC2]-ABSCISIC ACID INSENSITIVE3 [ABI3]-VAL)、RF(AUXINRESPONSE FACTOR)、RAV(RELATED TO ABI3 and VPl)和REM(REPRODUCTIVE MERISTEM)等4个家族.B3基因超家族主要存在于裸子植物、苔藓和绿藻类植物中,并在植物逆境胁迫响应和生长发育过程中起着极其重要的作用.目前已在拟南芥中发现了118个B3类转录因子,本文综述了拟南芥中B3转录因子基因超家族的系统发育和功能鉴定方面的研究进展.%The B3 transcription factor genes form a plant-specific B3 gene superfamily and can be further classified into four families:LAV (LEAFY COTYLEDON2 [LEC2]-ABSCISIC ACID INSENSITIVE3 [ABI3]-VAL),ARF (AUXIN RESPONSE FACTOR),RAV (RELATED TO ABI3 and VP1) and REM (REPRODUCTIVE MERISTEM) family.The B3 transcription factor genes exist mainly in gymnosperms,mosses and green algae and play extremely important roles in plant stress responses and plant growth and development.In Arabidopsis,118 B3 superfamily transcription factor genes have been identified.This review aims to overview the research progress of the phylogenetical and functional characterization of the B3 gene superfamily in Arabidopsis.

  18. The Development of Protein Microarrays and Their Applications in DNA-Protein and Protein-Protein Interaction Analyses of Arabidopsis Transcription Factors

    Institute of Scientific and Technical Information of China (English)

    Wei Gong; Kun He; Mike Covington; S.R Dinesh-Kumar; Michael Snyder; Stacey L.Harmer; Yu-Xian Zhu; Xing Wang Deng

    2008-01-01

    We used our collection of Arabidopsis transcription factor (TF) ORFeome clones to constructprotein microarrays containing as many as 802 TF proteins. These protein microarrays were used for both protein-DNA and proteinprotein interaction analyses. For protein-DNA interaction studies, we examined AP2/ERF family TFs and their cognate cis-elements. By careful comparison of the DNA-binding specificity of 13 TFs on the protein microarray with previous non-microarray data, we showed that protein microarrays provide an efficient and high throughput tool for genome-wide analysis of TF-DNA interactions. This microarray protein-DNA interaction analysis allowed us to derive a comprehensive view of DNA-binding profiles of AP2/ERF family proteins in Arabidopsis. It also revealed four TFs that bound the EE (evening element) and had the expected phased gene expression under clock-regulation, thus providing a basis for further functional analysis of their roles in clock regulation of gene expression. We also developed procedures for detecting protein interactions using this TF protein microarray and discovered four novel partners that interact with HY5, which can be validated by yeast two-hybrid assays. Thus, plant TF protein microarrays offer an attractive high-throughput alternative to traditional techniques for TF functional characterization on a global scale.

  19. The beet cyst nematode Heterodera schachtii modulates the expression of WRKY transcription factors in syncytia to favour its development in Arabidopsis roots.

    Science.gov (United States)

    Ali, Muhammad Amjad; Wieczorek, Krzysztof; Kreil, David P; Bohlmann, Holger

    2014-01-01

    Cyst nematodes invade the roots of their host plants as second stage juveniles and induce a syncytium which is the only source of nutrients throughout their life. A recent transcriptome analysis of syncytia induced by the beet cyst nematode Heterodera schachtii in Arabidopsis roots has shown that thousands of genes are up-regulated or down-regulated in syncytia as compared to root segments from uninfected plants. Among the down-regulated genes are many which code for WRKY transcription factors. Arabidopsis contains 66 WRKY genes with 59 represented by the ATH1 GeneChip. Of these, 28 were significantly down-regulated and 6 up-regulated in syncytia as compared to control root segments. We have studied here the down-regulated genes WRKY6, WRKY11, WRKY17 and WRKY33 in detail. We confirmed the down-regulation in syncytia with promoter::GUS lines. Using various overexpression lines and mutants it was shown that the down-regulation of these WRKY genes is important for nematode development, probably through interfering with plant defense reactions. In case of WRKY33, this might involve the production of the phytoalexin camalexin.

  20. The beet cyst nematode Heterodera schachtii modulates the expression of WRKY transcription factors in syncytia to favour its development in Arabidopsis roots.

    Directory of Open Access Journals (Sweden)

    Muhammad Amjad Ali

    Full Text Available Cyst nematodes invade the roots of their host plants as second stage juveniles and induce a syncytium which is the only source of nutrients throughout their life. A recent transcriptome analysis of syncytia induced by the beet cyst nematode Heterodera schachtii in Arabidopsis roots has shown that thousands of genes are up-regulated or down-regulated in syncytia as compared to root segments from uninfected plants. Among the down-regulated genes are many which code for WRKY transcription factors. Arabidopsis contains 66 WRKY genes with 59 represented by the ATH1 GeneChip. Of these, 28 were significantly down-regulated and 6 up-regulated in syncytia as compared to control root segments. We have studied here the down-regulated genes WRKY6, WRKY11, WRKY17 and WRKY33 in detail. We confirmed the down-regulation in syncytia with promoter::GUS lines. Using various overexpression lines and mutants it was shown that the down-regulation of these WRKY genes is important for nematode development, probably through interfering with plant defense reactions. In case of WRKY33, this might involve the production of the phytoalexin camalexin.

  1. The development of protein microarrays and their applications in DNA-protein and protein-protein interaction analyses of Arabidopsis transcription factors.

    Science.gov (United States)

    Gong, Wei; He, Kun; Covington, Mike; Dinesh-Kumar, S P; Snyder, Michael; Harmer, Stacey L; Zhu, Yu-Xian; Deng, Xing Wang

    2008-01-01

    We used our collection of Arabidopsis transcription factor (TF) ORFeome clones to construct protein microarrays containing as many as 802 TF proteins. These protein microarrays were used for both protein-DNA and protein-protein interaction analyses. For protein-DNA interaction studies, we examined AP2/ERF family TFs and their cognate cis-elements. By careful comparison of the DNA-binding specificity of 13 TFs on the protein microarray with previous non-microarray data, we showed that protein microarrays provide an efficient and high throughput tool for genome-wide analysis of TF-DNA interactions. This microarray protein-DNA interaction analysis allowed us to derive a comprehensive view of DNA-binding profiles of AP2/ERF family proteins in Arabidopsis. It also revealed four TFs that bound the EE (evening element) and had the expected phased gene expression under clock-regulation, thus providing a basis for further functional analysis of their roles in clock regulation of gene expression. We also developed procedures for detecting protein interactions using this TF protein microarray and discovered four novel partners that interact with HY5, which can be validated by yeast two-hybrid assays. Thus, plant TF protein microarrays offer an attractive high-throughput alternative to traditional techniques for TF functional characterization on a global scale.

  2. The Arabidopsis MYB96 Transcription Factor Is a Positive Regulator of ABSCISIC ACID-INSENSITIVE4 in the Control of Seed Germination.

    Science.gov (United States)

    Lee, Kyounghee; Lee, Hong Gil; Yoon, Seongmun; Kim, Hyun Uk; Seo, Pil Joon

    2015-06-01

    Seed germination is a key developmental transition that initiates the plant life cycle. The timing of germination is determined by the coordinated action of two phytohormones, gibberellin and abscisic acid (ABA). In particular, ABA plays a key role in integrating environmental information and inhibiting the germination process. The utilization of embryonic lipid reserves contributes to seed germination by acting as an energy source, and ABA suppresses lipid degradation to modulate the germination process. Here, we report that the ABA-responsive R2R3-type MYB transcription factor MYB96, which is highly expressed in embryo, regulates seed germination by controlling the expression of abscisic acid-insensitive4 (ABI4) in Arabidopsis (Arabidopsis thaliana). In the presence of ABA, germination was accelerated in MYB96-deficient myb96-1 seeds, whereas the process was significantly delayed in MYB96-overexpressing activation-tagging myb96-ox seeds. Consistently, myb96-1 seeds degraded a larger extent of lipid reserves even in the presence of ABA, while reduced lipid mobilization was observed in myb96-ox seeds. MYB96 directly regulates ABI4, which acts as a repressor of lipid breakdown, to define its spatial and temporal expression. Genetic analysis further demonstrated that ABI4 is epistatic to MYB96 in the control of seed germination. Taken together, the MYB96-ABI4 module regulates lipid mobilization specifically in the embryo to ensure proper seed germination under suboptimal conditions.

  3. CFLAP1 and CFLAP2 Are Two bHLH Transcription Factors Participating in Synergistic Regulation of AtCFL1-Mediated Cuticle Development in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Shibai Li

    2016-01-01

    Full Text Available The cuticle is a hydrophobic lipid layer covering the epidermal cells of terrestrial plants. Although many genes involved in Arabidopsis cuticle development have been identified, the transcriptional regulation of these genes is largely unknown. Previously, we demonstrated that AtCFL1 negatively regulates cuticle development by interacting with the HD-ZIP IV transcription factor HDG1. Here, we report that two bHLH transcription factors, AtCFL1 associated protein 1 (CFLAP1 and CFLAP2, are also involved in AtCFL1-mediated regulation of cuticle development. CFLAP1 and CFLAP2 interact with AtCFL1 both in vitro and in vivo. Overexpression of either CFLAP1 or CFLAP2 led to expressional changes of genes involved in fatty acids, cutin and wax biosynthesis pathways and caused multiple cuticle defective phenotypes such as organ fusion, breakage of the cuticle layer and decreased epicuticular wax crystal loading. Functional inactivation of CFLAP1 and CFLAP2 by chimeric repression technology caused opposite phenotypes to the CFLAP1 overexpressor plants. Interestingly, we find that, similar to the transcription factor HDG1, the function of CFLAP1 in cuticle development is dependent on the presence of AtCFL1. Furthermore, both HDG1 and CFLAP1/2 interact with the same C-terminal C4 zinc finger domain of AtCFL1, a domain that is essential for AtCFL1 function. These results suggest that AtCFL1 may serve as a master regulator in the transcriptional regulation of cuticle development, and that CFLAP1 and CFLAP2 are involved in the AtCFL1-mediated regulation pathway, probably through competing with HDG1 to bind to AtCFL1.

  4. STOP2 Activates Transcription of Several Genesfor AI- and Low pH-Tolerance that Are Regulatedby STOP1 in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    The zinc-finger protein STOP1 (sensitive to proton rhizotoxicity 1) regulates transcription of multiple genescritical for tolerance to aluminum (AI) and low pH in Arabidopsis. We evaluated the contributions of genes that are sup-pressed in the stop1 mutant to AI- and low pH-tolerance using T-DNA-inserted disruptants, and transgenic stop1 mutantsexpressing each of the suppressed genes. STOP2, a STOP1 homolog, partially recovered AI- and low pH-tolerance byrecovering the expression of genes regulated by STOP1. Growth and root tip viability under proton stress were partiallyrescued in the STOP2-complemented line. STOP2 localized in the nucleus and regulated transcription of two genes (PGIP1and PGIP2) associated with cell wall stabilization at low pH. GUS assays revealed that STOP1 and STOP2 showed similarcellular expression in the root. However, the expression level of STOP2 was much lower than that of STOP1. In a STOP1promoter::STOP2-complemented line, AI tolerance was slightly recovered, concomitant with the recovery of expressionof ALS3 (aluminum sensitive 3) and AtMATE (Arabidopsis thaliana multidrug and toxic compound extrusion), while theexpression of AtALMT1 (aluminum-activated malate transporter 1) was not recovered. These analyses indicated thatSTOP2 is a physiologically minor isoform of STOP1, but it can activate expression of some genes regulated by STOP1.

  5. The WRKY6 transcription factor modulates PHOSPHATE1 expression in response to low Pi stress in Arabidopsis.

    Science.gov (United States)

    Chen, Yi-Fang; Li, Li-Qin; Xu, Qian; Kong, You-Han; Wang, Hui; Wu, Wei-Hua

    2009-11-01

    Arabidopsis thaliana WRKY family comprises 74 members and some of them are involved in plant responses to biotic and abiotic stresses. This study demonstrated that WRKY6 is involved in Arabidopsis responses to low-Pi stress through regulating PHOSPHATE1 (PHO1) expression. WRKY6 overexpression lines, similar to the pho1 mutant, were more sensitive to low Pi stress and had lower Pi contents in shoots compared with wild-type seedlings and the wrky6-1 mutant. Immunoprecipitation assays demonstrated that WRKY6 can bind to two W-boxes of the PHO1 promoter. RNA gel blot and beta-glucuronidase activity assays showed that PHO1 expression was repressed in WRKY6-overexpressing lines and enhanced in the wrky6-1 mutant. Low Pi treatment reduced WRKY6 binding to the PHO1 promoter, which indicates that PHO1 regulation by WRKY6 is Pi dependent and that low Pi treatment may release inhibition of PHO1 expression. Protein gel blot analysis showed that the decrease in WRKY6 protein induced by low Pi treatment was inhibited by a 26S proteosome inhibitor, MG132, suggesting that low Pi-induced release of PHO1 repression may result from 26S proteosome-mediated proteolysis. In addition, WRKY42 also showed binding to W-boxes of the PHO1 promoter and repressed PHO1 expression. Our results demonstrate that WRKY6 and WRKY42 are involved in Arabidopsis responses to low Pi stress by regulation of PHO1 expression.

  6. Arabidopsis inositol pentakisphosphate 2-kinase, AtIPK1, is required for growth and modulates phosphate homeostasis at the transcriptional level.

    Science.gov (United States)

    Kuo, Hui-Fen; Chang, Tzu-Yun; Chiang, Su-Fen; Wang, Wei-Di; Charng, Yee-Yung; Chiou, Tzyy-Jen

    2014-11-01

    Inositol hexakisphosphate (IP6 ) provides a phosphorous reservoir in plant seeds; in addition, along with its biosynthesis intermediates and derivatives, IP6 also plays important roles in diverse developmental and physiological processes. Disruption of the Arabidopsis inositol pentakisphosphate 2-kinase coding gene AtIPK1 was previously shown to reduce IP6 content in vegetative tissues and affect phosphate (Pi) sensing. Here we show that AtIPK1 is required for sustaining plant growth, as null mutants are non-viable. An incomplete loss-of-function mutant, atipk1-1, exhibited disturbed Pi homeostasis and overaccumulated Pi as a consequence of increased Pi uptake activity and root-to-shoot Pi translocation. The atipk1-1 mutants also showed a Pi deficiency-like root system architecture with reduced primary root and enhanced lateral root growth. Transcriptome analysis indicated that a subset of Pi starvation-responsive genes was transcriptionally perturbed in the atipk1-1 mutants and the expression of multiple genes involved in Pi uptake, allocation, and remobilization was increased. Genetic and transcriptional analyses suggest that disturbance of Pi homeostasis caused by atipk1 mutation involved components in addition to PHR1(-like) transcription factors. Notably, the transcriptional increase of a number of Pi starvation-responsive genes in the atipk1-1 mutants is correlated with the reduction of histone variant H2A.Z occupation in chromatin. The myo-inositol-1-phosphate synthase mutants, atmips1 and atmips2 with comparable reduction in vegetative IP6 to that in the atipk1-1 mutants did not overaccumulate Pi, suggesting that Pi homeostasis modulated by AtIPK1 is not solely attributable to IP6 level. This study reveals that AtIPK1 has important roles in growth and Pi homeostasis.

  7. The BEACH Domain Protein SPIRRIG Is Essential for Arabidopsis Salt Stress Tolerance and Functions as a Regulator of Transcript Stabilization and Localization.

    Directory of Open Access Journals (Sweden)

    Alexandra Steffens

    2015-07-01

    Full Text Available Members of the highly conserved class of BEACH domain containing proteins (BDCPs have been established as broad facilitators of protein-protein interactions and membrane dynamics in the context of human diseases like albinism, bleeding diathesis, impaired cellular immunity, cancer predisposition, and neurological dysfunctions. Also, the Arabidopsis thaliana BDCP SPIRRIG (SPI is important for membrane integrity, as spi mutants exhibit split vacuoles. In this work, we report a novel molecular function of the BDCP SPI in ribonucleoprotein particle formation. We show that SPI interacts with the P-body core component DECAPPING PROTEIN 1 (DCP1, associates to mRNA processing bodies (P-bodies, and regulates their assembly upon salt stress. The finding that spi mutants exhibit salt hypersensitivity suggests that the local function of SPI at P-bodies is of biological relevance. Transcriptome-wide analysis revealed qualitative differences in the salt stress-regulated transcriptional response of Col-0 and spi. We show that SPI regulates the salt stress-dependent post-transcriptional stabilization, cytoplasmic agglomeration, and localization to P-bodies of a subset of salt stress-regulated mRNAs. Finally, we show that the PH-BEACH domains of SPI and its human homolog FAN (Factor Associated with Neutral sphingomyelinase activation interact with DCP1 isoforms from plants, mammals, and yeast, suggesting the evolutionary conservation of an association of BDCPs and P-bodies.

  8. Enhancement of Chlorogenic Acid Production in Hairy Roots of Platycodon grandiflorum by Over-Expression of An Arabidopsis thaliana Transcription Factor AtPAP1

    Directory of Open Access Journals (Sweden)

    Pham Anh Tuan

    2014-08-01

    Full Text Available To improve the production of chlorogenic acid (CGA in hairy roots of Platycodon grandiflorum, we induced over-expression of Arabidopsis thaliana transcription factor production of anthocyanin pigment (AtPAP1 using an Agrobacterium rhizogenes-mediated transformation system. Twelve hairy root lines showing over-expression of AtPAP1 were generated. In order to investigate the regulation of AtPAP1 on the activities of CGA biosynthetic genes, the expression levels of seven P. grandiflorum CGA biosynthetic genes were analyzed in the hairy root line that had the greatest accumulation of AtPAP1 transcript, OxPAP1-1. The introduction of AtPAP1 increased the mRNA levels of all examined CGA biosynthetic genes and resulted in a 900% up-regulation of CGA accumulation in OxPAP1-1 hairy roots relative to controls. This suggests that P. grandiflorum hairy roots that over-express the AtPAP1 gene are a potential alternative source of roots for the production of CGA.

  9. Enhancement of chlorogenic acid production in hairy roots of Platycodon grandiflorum by over-expression of an Arabidopsis thaliana transcription factor AtPAP1.

    Science.gov (United States)

    Tuan, Pham Anh; Kwon, Do Yeon; Lee, Sanghyun; Arasu, Mariadhas Valan; Al-Dhabi, Naif Abdullah; Park, Nam Il; Park, Sang Un

    2014-08-22

    To improve the production of chlorogenic acid (CGA) in hairy roots of Platycodon grandiflorum, we induced over-expression of Arabidopsis thaliana transcription factor production of anthocyanin pigment (AtPAP1) using an Agrobacterium rhizogenes-mediated transformation system. Twelve hairy root lines showing over-expression of AtPAP1 were generated. In order to investigate the regulation of AtPAP1 on the activities of CGA biosynthetic genes, the expression levels of seven P. grandiflorum CGA biosynthetic genes were analyzed in the hairy root line that had the greatest accumulation of AtPAP1 transcript, OxPAP1-1. The introduction of AtPAP1 increased the mRNA levels of all examined CGA biosynthetic genes and resulted in a 900% up-regulation of CGA accumulation in OxPAP1-1 hairy roots relative to controls. This suggests that P. grandiflorum hairy roots that over-express the AtPAP1 gene are a potential alternative source of roots for the production of CGA.

  10. A DNA-binding-site landscape and regulatory network analysis for NAC transcription factors in Arabidopsis thaliana

    DEFF Research Database (Denmark)

    Lindemose, Søren; Jensen, Michael Krogh; de Velde, Jan Van

    2014-01-01

    regulatory networks of 12 NAC transcription factors. Our data offer specific single-base resolution fingerprints for most TFs studied and indicate that NAC DNA-binding specificities might be predicted from their DNA-binding domain's sequence. The developed methodology, including the application...... of complementary functional genomics filters, makes it possible to translate, for each TF, protein binding microarray data into a set of high-quality target genes. With this approach, we confirm NAC target genes reported from independent in vivo analyses. We emphasize that candidate target gene sets together......Target gene identification for transcription factors is a prerequisite for the systems wide understanding of organismal behaviour. NAM-ATAF1/2-CUC2 (NAC) transcription factors are amongst the largest transcription factor families in plants, yet limited data exist from unbiased approaches to resolve...

  11. Dual-level regulation of ACC synthase activity by MPK3/MPK6 cascade and its downstream WRKY transcription factor during ethylene induction in Arabidopsis.

    Science.gov (United States)

    Li, Guojing; Meng, Xiangzong; Wang, Ruigang; Mao, Guohong; Han, Ling; Liu, Yidong; Zhang, Shuqun

    2012-06-01

    Plants under pathogen attack produce high levels of ethylene, which plays important roles in plant immunity. Previously, we reported the involvement of ACS2 and ACS6, two Type I ACS isoforms, in Botrytis cinerea-induced ethylene biosynthesis and their regulation at the protein stability level by MPK3 and MPK6, two Arabidopsis pathogen-responsive mitogen-activated protein kinases (MAPKs). The residual ethylene induction in the acs2/acs6 double mutant suggests the involvement of additional ACS isoforms. It is also known that a subset of ACS genes, including ACS6, is transcriptionally induced in plants under stress or pathogen attack. However, the importance of ACS gene activation and the regulatory mechanism(s) are not clear. In this report, we demonstrate using genetic analysis that ACS7 and ACS11, two Type III ACS isoforms, and ACS8, a Type II ACS isoform, also contribute to the B. cinerea-induced ethylene production. In addition to post-translational regulation, transcriptional activation of the ACS genes also plays a critical role in sustaining high levels of ethylene induction. Interestingly, MPK3 and MPK6 not only control the stability of ACS2 and ACS6 proteins via direct protein phosphorylation but also regulate the expression of ACS2 and ACS6 genes. WRKY33, another MPK3/MPK6 substrate, is involved in the MPK3/MPK6-induced ACS2/ACS6 gene expression based on genetic analyses. Furthermore, chromatin-immunoprecipitation assay reveals the direct binding of WRKY33 to the W-boxes in the promoters of ACS2 and ACS6 genes in vivo, suggesting that WRKY33 is directly involved in the activation of ACS2 and ACS6 expression downstream of MPK3/MPK6 cascade in response to pathogen invasion. Regulation of ACS activity by MPK3/MPK6 at both transcriptional and protein stability levels plays a key role in determining the kinetics and magnitude of ethylene induction.

  12. The bacterial effector HopX1 targets JAZ transcriptional repressors to activate jasmonate signaling and promote infection in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Selena Gimenez-Ibanez

    2014-02-01

    Full Text Available Pathogenicity of Pseudomonas syringae is dependent on a type III secretion system, which secretes a suite of virulence effector proteins into the host cytoplasm, and the production of a number of toxins such as coronatine (COR, which is a mimic of the plant hormone jasmonate-isoleuce (JA-Ile. Inside the plant cell, effectors target host molecules to subvert the host cell physiology and disrupt defenses. However, despite the fact that elucidating effector action is essential to understanding bacterial pathogenesis, the molecular function and host targets of the vast majority of effectors remain largely unknown. Here, we found that effector HopX1 from Pseudomonas syringae pv. tabaci (Pta 11528, a strain that does not produce COR, interacts with and promotes the degradation of JAZ proteins, a key family of JA-repressors. We show that hopX1 encodes a cysteine protease, activity that is required for degradation of JAZs by HopX1. HopX1 associates with JAZ proteins through its central ZIM domain and degradation occurs in a COI1-independent manner. Moreover, ectopic expression of HopX1 in Arabidopsis induces the expression of JA-dependent genes, represses salicylic acid (SA-induced markers, and complements the growth of a COR-deficient P. syringae pv. tomato (Pto DC3000 strain during natural bacterial infections. Furthermore, HopX1 promoted susceptibility when delivered by the natural type III secretion system, to a similar extent as the addition of COR, and this effect was dependent on its catalytic activity. Altogether, our results indicate that JAZ proteins are direct targets of bacterial effectors to promote activation of JA-induced defenses and susceptibility in Arabidopsis. HopX1 illustrates a paradigm of an alternative evolutionary solution to COR with similar physiological outcome.

  13. Integration of genome-scale modeling and transcript profiling reveals metabolic pathways underlying light and temperature acclimation in Arabidopsis.

    Science.gov (United States)

    Töpfer, Nadine; Caldana, Camila; Grimbs, Sergio; Willmitzer, Lothar; Fernie, Alisdair R; Nikoloski, Zoran

    2013-04-01

    Understanding metabolic acclimation of plants to challenging environmental conditions is essential for dissecting the role of metabolic pathways in growth and survival. As stresses involve simultaneous physiological alterations across all levels of cellular organization, a comprehensive characterization of the role of metabolic pathways in acclimation necessitates integration of genome-scale models with high-throughput data. Here, we present an integrative optimization-based approach, which, by coupling a plant metabolic network model and transcriptomics data, can predict the metabolic pathways affected in a single, carefully controlled experiment. Moreover, we propose three optimization-based indices that characterize different aspects of metabolic pathway behavior in the context of the entire metabolic network. We demonstrate that the proposed approach and indices facilitate quantitative comparisons and characterization of the plant metabolic response under eight different light and/or temperature conditions. The predictions of the metabolic functions involved in metabolic acclimation of Arabidopsis thaliana to the changing conditions are in line with experimental evidence and result in a hypothesis about the role of homocysteine-to-Cys interconversion and Asn biosynthesis. The approach can also be used to reveal the role of particular metabolic pathways in other scenarios, while taking into consideration the entirety of characterized plant metabolism.

  14. The bHLH transcription factor bHLH104 interacts with IAA-LEUCINE RESISTANT3 and modulates iron homeostasis in Arabidopsis.

    Science.gov (United States)

    Zhang, Jie; Liu, Bing; Li, Mengshu; Feng, Dongru; Jin, Honglei; Wang, Peng; Liu, Jun; Xiong, Feng; Wang, Jinfa; Wang, Hong-Bin

    2015-03-01

    Iron (Fe) is an indispensable micronutrient for plant growth and development. The regulation of Fe homeostasis in plants is complex and involves a number of transcription factors. Here, we demonstrate that a basic helix-loop-helix (bHLH) transcription factor, bHLH104, belonging to the IVc subgroup of bHLH family, acts as a key component positively regulating Fe deficiency responses. Knockout of bHLH104 in Arabidopsis thaliana greatly reduced tolerance to Fe deficiency, whereas overexpression of bHLH104 had the opposite effect and led to accumulation of excess Fe in soil-grown conditions. The activation of Fe deficiency-inducible genes was substantially suppressed by loss of bHLH104. Further investigation showed that bHLH104 interacted with another IVc subgroup bHLH protein, IAA-LEUCINE RESISTANT3 (ILR3), which also plays an important role in Fe homeostasis. Moreover, bHLH104 and ILR3 could bind directly to the promoters of Ib subgroup bHLH genes and POPEYE (PYE) functioning in the regulation of Fe deficiency responses. Interestingly, genetic analysis showed that loss of bHLH104 could decrease the tolerance to Fe deficiency conferred by the lesion of BRUTUS, which encodes an E3 ligase and interacts with bHLH104. Collectively, our data support that bHLH104 and ILR3 play pivotal roles in the regulation of Fe deficiency responses via targeting Ib subgroup bHLH genes and PYE expression.

  15. Arabidopsis ABA Receptor RCAR1/PYL9 Interacts with an R2R3-Type MYB Transcription Factor, AtMYB44

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    Dekuan Li

    2014-05-01

    Full Text Available Abscisic acid (ABA signaling plays important roles in plant growth, development and adaptation to various stresses. RCAR1/PYL9 has been known as a cytoplasm and nuclear ABA receptor in Arabidopsis. To obtain further insight into the regulatory mechanism of RCAR1/PYL9, a yeast two-hybrid approach was performed to screen for RCAR1/PYL9-interacting proteins and an R2R3-type MYB transcription factor, AtMYB44, was identified. The interaction between RCAR1/PYL9 and AtMYB44 was further confirmed by glutathione S-transferase (GST pull-down and bimolecular fluorescence complementation (BiFC assays. Gene expression analysis showed that AtMYB44 negatively regulated the expression of ABA-responsive gene RAB18, in contrast to the opposite role reported for RCAR1/PYL9. Competitive GST pull-down assay and analysis of phosphatase activity demonstrated that AtMYB44 and ABI1 competed for binding to RCAR1/PYL9 and thereby reduced the inhibitory effect of RCAR1/PYL9 on ABI1 phosphatase activity in the presence of ABA in vitro. Furthermore, transient activation assay in protoplasts revealed AtMYB44 probably also decreased RCAR1/PYL9-mediated inhibition of ABI1 activity in vivo. Taken together, our work provides a reasonable molecular mechanism of AtMYB44 in ABA signaling.

  16. Induction of dormancy in Arabidopsis summer annuals requires parallel regulation of DOG1 and hormone metabolism by low temperature and CBF transcription factors.

    Science.gov (United States)

    Kendall, Sarah L; Hellwege, Anja; Marriot, Poppy; Whalley, Celina; Graham, Ian A; Penfield, Steven

    2011-07-01

    Summer annuals overwinter as seeds in the soil seed bank. This is facilitated by a cold-induced increase in dormancy during seed maturation followed by a switch to a state during seed imbibition in which cold instead promotes germination. Here, we show that the seed maturation transcriptome in Arabidopsis thaliana is highly temperature sensitive and reveal that low temperature during seed maturation induces several genes associated with dormancy, including DELAY OF GERMINATION1 (DOG1), and influences gibberellin and abscisic acid levels in mature seeds. Mutants lacking DOG1, or with altered gibberellin or abscisic acid synthesis or signaling, in turn show reduced ability to enter the deeply dormant states in response to low seed maturation temperatures. In addition, we find that DOG1 promotes gibberellin catabolism during maturation. We show that C-REPEAT BINDING FACTORS (CBFs) are necessary for regulation of dormancy and of GA2OX6 and DOG1 expression caused by low temperatures. However, the temperature sensitivity of CBF transcription is markedly reduced in seeds and is absent in imbibed seeds. Our data demonstrate that inhibition of CBF expression is likely a critical feature allowing cold to promote rather than inhibit germination and support a model in which CBFs act in parallel to a low-temperature signaling pathway in the regulation of dormancy.

  17. Induction of Dormancy in Arabidopsis Summer Annuals Requires Parallel Regulation of DOG1 and Hormone Metabolism by Low Temperature and CBF Transcription Factors[W][OA

    Science.gov (United States)

    Kendall, Sarah L.; Hellwege, Anja; Marriot, Poppy; Whalley, Celina; Graham, Ian A.; Penfield, Steven

    2011-01-01

    Summer annuals overwinter as seeds in the soil seed bank. This is facilitated by a cold-induced increase in dormancy during seed maturation followed by a switch to a state during seed imbibition in which cold instead promotes germination. Here, we show that the seed maturation transcriptome in Arabidopsis thaliana is highly temperature sensitive and reveal that low temperature during seed maturation induces several genes associated with dormancy, including DELAY OF GERMINATION1 (DOG1), and influences gibberellin and abscisic acid levels in mature seeds. Mutants lacking DOG1, or with altered gibberellin or abscisic acid synthesis or signaling, in turn show reduced ability to enter the deeply dormant states in response to low seed maturation temperatures. In addition, we find that DOG1 promotes gibberellin catabolism during maturation. We show that C-REPEAT BINDING FACTORS (CBFs) are necessary for regulation of dormancy and of GA2OX6 and DOG1 expression caused by low temperatures. However, the temperature sensitivity of CBF transcription is markedly reduced in seeds and is absent in imbibed seeds. Our data demonstrate that inhibition of CBF expression is likely a critical feature allowing cold to promote rather than inhibit germination and support a model in which CBFs act in parallel to a low-temperature signaling pathway in the regulation of dormancy. PMID:21803937

  18. 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

    2016-11-22

    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.

  19. AtTGA4, a bZIP transcription factor, confers drought resistance by enhancing nitrate transport and assimilation in Arabidopsis thaliana.

    Science.gov (United States)

    Zhong, Li; Chen, Dandan; Min, Donghong; Li, Weiwei; Xu, Zhaoshi; Zhou, Yongbin; Li, Liancheng; Chen, Ming; Ma, Youzhi

    2015-02-13

    To cope with environmental stress caused by global climate change and excessive nitrogen application, it is important to improve water and nitrogen use efficiencies in crop plants. It has been reported that higher nitrogen uptake could alleviate the damaging impact of drought stress. However, there is scant evidence to explain how nitrogen uptake affects drought resistance. In this study we observed that bZIP transcription factor AtTGA4 (TGACG motif-binding factor 4) was induced by both drought and low nitrogen stresses, and that overexpression of AtTGA4 simultaneously improved drought resistance and reduced nitrogen starvation in Arabidopsis. Following drought stress there were higher nitrogen and proline contents in transgenic AtTGA4 plants than in wild type controls, and activity of the key enzyme nitrite reductase (NIR) involved in nitrate assimilation processes was also higher. Expressions of the high-affinity nitrate transporter genes NRT2.1 and NRT2.2 and nitrate reductase genes NIA1 and NIA2 in transgenic plants were all higher than in wild type indicating that higher levels of nitrate transport and assimilation activity contributed to enhanced drought resistance of AtTGA4 transgenic plants. Thus genetic transformation with AtTGA4 may provide a new approach to simultaneously improve crop tolerance to drought and low nitrogen stresses.

  20. Phloem parenchyma transfer cells in Arabidopsis – an experimental system to identify transcriptional regulators of wall ingrowth formation

    OpenAIRE

    Arun Chinnappa, Kiruba S.; Nguyen, Thi Thu S.; Hou, Jiexi; Wu, Yuzhou; McCurdy, David W.

    2013-01-01

    In species performing apoplasmic loading, phloem cells adjacent to sieve elements often develop into transfer cells (TCs) with wall ingrowths. The highly invaginated wall ingrowths serve to amplify plasma membrane surface area to achieve increased rates of apoplasmic transport, and may also serve as physical barriers to deter pathogen invasion. Wall ingrowth formation in TCs therefore plays an important role in phloem biology, however, the transcriptional switches regulating the deposition of...

  1. Dual-level regulation of ACC synthase activity by MPK3/MPK6 cascade and its downstream WRKY transcription factor during ethylene induction in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Guojing Li

    2012-06-01

    Full Text Available Plants under pathogen attack produce high levels of ethylene, which plays important roles in plant immunity. Previously, we reported the involvement of ACS2 and ACS6, two Type I ACS isoforms, in Botrytis cinerea-induced ethylene biosynthesis and their regulation at the protein stability level by MPK3 and MPK6, two Arabidopsis pathogen-responsive mitogen-activated protein kinases (MAPKs. The residual ethylene induction in the acs2/acs6 double mutant suggests the involvement of additional ACS isoforms. It is also known that a subset of ACS genes, including ACS6, is transcriptionally induced in plants under stress or pathogen attack. However, the importance of ACS gene activation and the regulatory mechanism(s are not clear. In this report, we demonstrate using genetic analysis that ACS7 and ACS11, two Type III ACS isoforms, and ACS8, a Type II ACS isoform, also contribute to the B. cinerea-induced ethylene production. In addition to post-translational regulation, transcriptional activation of the ACS genes also plays a critical role in sustaining high levels of ethylene induction. Interestingly, MPK3 and MPK6 not only control the stability of ACS2 and ACS6 proteins via direct protein phosphorylation but also regulate the expression of ACS2 and ACS6 genes. WRKY33, another MPK3/MPK6 substrate, is involved in the MPK3/MPK6-induced ACS2/ACS6 gene expression based on genetic analyses. Furthermore, chromatin-immunoprecipitation assay reveals the direct binding of WRKY33 to the W-boxes in the promoters of ACS2 and ACS6 genes in vivo, suggesting that WRKY33 is directly involved in the activation of ACS2 and ACS6 expression downstream of MPK3/MPK6 cascade in response to pathogen invasion. Regulation of ACS activity by MPK3/MPK6 at both transcriptional and protein stability levels plays a key role in determining the kinetics and magnitude of ethylene induction.

  2. HFR1 sequesters PIF1 to govern the transcriptional network underlying light-initiated seed germination in Arabidopsis.

    Science.gov (United States)

    Shi, Hui; Zhong, Shangwei; Mo, Xiaorong; Liu, Na; Nezames, Cynthia D; Deng, Xing Wang

    2013-10-01

    Seed germination is the first step for seed plants to initiate a new life cycle. Light plays a predominant role in promoting seed germination, where the initial phase is mediated by photoreceptor phytochrome B (phyB). Previous studies showed that phytochrome-interacting factor1 (PIF1) represses seed germination downstream of phyB. Here, we identify a positive regulator of phyB-dependent seed germination, long hypocotyl in far-red1 (HFR1). HFR1 blocks PIF1 transcriptional activity by forming a heterodimer with PIF1 that prevents PIF1 from binding to DNA. Our whole-genomic analysis shows that HFR1 and PIF1 oppositely mediate the light-regulated transcriptome in imbibed seeds. Through the HFR1-PIF1 module, light regulates expression of numerous genes involved in cell wall loosening, cell division, and hormone pathways to initiate seed germination. The functionally antagonistic HFR1-PIF1 pair constructs a fail-safe mechanism for fine-tuning seed germination during low-level illumination, ensuring a rapid response to favorable environmental changes. This study identifies the HFR1-PIF1 pair as a central module directing the whole genomic transcriptional network to rapidly initiate light-induced seed germination.

  3. Phosphatidic Acid Interacts with a MYB Transcription Factor and Regulates Its Nuclear Localization and Function in Arabidopsis[C][W

    Science.gov (United States)

    Yao, Hongyan; Wang, Geliang; Guo, Liang; Wang, Xuemin

    2013-01-01

    Phosphatidic acid (PA) has emerged as a class of cellular mediators involved in various cellular and physiological processes, but little is known about its mechanism of action. Here we show that PA interacts with WEREWOLF (WER), a R2R3 MYB transcription factor involved in root hair formation. The PA-interacting region is confined to the end of the R2 subdomain. The ablation of the PA binding motif has no effect on WER binding to DNA, but abolishes its nuclear localization and its function in regulating epidermal cell fate. Inhibition of PA production by phospholipase Dζ also suppresses WER’s nuclear localization, root hair formation, and elongation. These results suggest a role for PA in promoting protein nuclear localization. PMID:24368785

  4. Phosphatidic acid interacts with a MYB transcription factor and regulates its nuclear localization and function in Arabidopsis.

    Science.gov (United States)

    Yao, Hongyan; Wang, Geliang; Guo, Liang; Wang, Xuemin

    2013-12-01

    Phosphatidic acid (PA) has emerged as a class of cellular mediators involved in various cellular and physiological processes, but little is known about its mechanism of action. Here we show that PA interacts with werewolf (WER), a R2R3 MYB transcription factor involved in root hair formation. The PA-interacting region is confined to the end of the R2 subdomain. The ablation of the PA binding motif has no effect on WER binding to DNA, but abolishes its nuclear localization and its function in regulating epidermal cell fate. Inhibition of PA production by phospholipase Dζ also suppresses WER's nuclear localization, root hair formation, and elongation. These results suggest a role for PA in promoting protein nuclear localization.

  5. GBF1, a transcription factor of blue light signaling in Arabidopsis, is degraded in the dark by a proteasome-mediated pathway independent of COP1 and SPA1.

    Science.gov (United States)

    Mallappa, Chandrashekara; Singh, Aparna; Ram, Hathi; Chattopadhyay, Sudip

    2008-12-19

    Arabidopsis GBF1/ZBF2 is a bZIP transcription factor that plays dual but opposite regulatory roles in cryptochrome-mediated blue light signaling. Here, we show the genetic and molecular interrelation of GBF1 with two well characterized negative regulators of light signaling, COP1 and SPA1, in photomorphogenic growth and light-regulated gene expression. Our results further reveal that GBF1 protein is less abundant in the dark-grown seedlings and is degraded by a proteasome-mediated pathway independent of COP1 and SPA1. Furthermore, COP1 physically interacts with GBF1 and is required for the optimum accumulation of GBF1 protein in light-grown seedlings. Taken together, this study provides a mechanistic view of concerted function of three important regulators in Arabidopsis seedling development.

  6. Overexpression of the Transcription Factors GmSHN1 and GmSHN9 Differentially Regulates Wax and Cutin Biosynthesis, Alters Cuticle Properties, and Changes Leaf Phenotypes in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Yangyang Xu

    2016-04-01

    Full Text Available SHINE (SHN/WIN clade proteins, transcription factors of the plant-specific APETALA 2/ethylene-responsive element binding factor (AP2/ERF family, have been proven to be involved in wax and cutin biosynthesis. Glycine max is an important economic crop, but its molecular mechanism of wax biosynthesis is rarely characterized. In this study, 10 homologs of Arabidopsis SHN genes were identified from soybean. These homologs were different in gene structures and organ expression patterns. Constitutive expression of each of the soybean SHN genes in Arabidopsis led to different leaf phenotypes, as well as different levels of glossiness on leaf surfaces. Overexpression of GmSHN1 and GmSHN9 in Arabidopsis exhibited 7.8-fold and 9.9-fold up-regulation of leaf cuticle wax productions, respectively. C31 and C29 alkanes contributed most to the increased wax contents. Total cutin contents of leaves were increased 11.4-fold in GmSHN1 overexpressors and 5.7-fold in GmSHN9 overexpressors, mainly through increasing C16:0 di-OH and dioic acids. GmSHN1 and GmSHN9 also altered leaf cuticle membrane ultrastructure and increased water loss rate in transgenic Arabidopsis plants. Transcript levels of many wax and cutin biosynthesis and leaf development related genes were altered in GmSHN1 and GmSHN9 overexpressors. Overall, these results suggest that GmSHN1 and GmSHN9 may differentially regulate the leaf development process as well as wax and cutin biosynthesis.

  7. Overexpression of the Transcription Factors GmSHN1 and GmSHN9 Differentially Regulates Wax and Cutin Biosynthesis, Alters Cuticle Properties, and Changes Leaf Phenotypes in Arabidopsis.

    Science.gov (United States)

    Xu, Yangyang; Wu, Hanying; Zhao, Mingming; Wu, Wang; Xu, Yinong; Gu, Dan

    2016-04-21

    SHINE (SHN/WIN) clade proteins, transcription factors of the plant-specific APETALA 2/ethylene-responsive element binding factor (AP2/ERF) family, have been proven to be involved in wax and cutin biosynthesis. Glycine max is an important economic crop, but its molecular mechanism of wax biosynthesis is rarely characterized. In this study, 10 homologs of Arabidopsis SHN genes were identified from soybean. These homologs were different in gene structures and organ expression patterns. Constitutive expression of each of the soybean SHN genes in Arabidopsis led to different leaf phenotypes, as well as different levels of glossiness on leaf surfaces. Overexpression of GmSHN1 and GmSHN9 in Arabidopsis exhibited 7.8-fold and 9.9-fold up-regulation of leaf cuticle wax productions, respectively. C31 and C29 alkanes contributed most to the increased wax contents. Total cutin contents of leaves were increased 11.4-fold in GmSHN1 overexpressors and 5.7-fold in GmSHN9 overexpressors, mainly through increasing C16:0 di-OH and dioic acids. GmSHN1 and GmSHN9 also altered leaf cuticle membrane ultrastructure and increased water loss rate in transgenic Arabidopsis plants. Transcript levels of many wax and cutin biosynthesis and leaf development related genes were altered in GmSHN1 and GmSHN9 overexpressors. Overall, these results suggest that GmSHN1 and GmSHN9 may differentially regulate the leaf development process as well as wax and cutin biosynthesis.

  8. Ethylene antagonizes salt-induced growth retardation and cell death process via transcriptional controlling of ethylene-, BAG- and senescence-associated genes in Arabidopsis

    Directory of Open Access Journals (Sweden)

    YaJie ePan

    2016-05-01

    Full Text Available The existing question whether ethylene is involved in the modulation of salt-induced cell death to mediate plant salt tolerance is important for understanding the salt tolerance mechanisms. Here, we employed Arabidopsis plants to study the possible role of ethylene in salt-induced growth inhibition and programmed cell death (PCD profiles. The root length, DNA ladder and cell death indicated by Evan’s blue detection were measured by compared to the control or salt-stressed seedlings. Secondly, the protoplasts isolated from plant leaves and dyed with Annexin V-FITC were subjected to flow cytometric (FCM assay. Our results showed that ethylene works effectively in seedling protoplasts, antagonizing salt-included root retardation and restraining cell death both in seedlings or protoplasts. Due to salinity, the entire or partial insensitivity of ethylene signaling resulted in an elevated levels of cell death in ein2-5 and ein3-1 plants and the event were amended in ctr1-1 plants after salt treatment. The subsequent experiment with exogenous ACC further corroborated that ethylene could modulate salt-induced PCD process actively. Plant Bcl-2-associated athanogene (BAG family genes are recently identified to play an extensive role in plant PCD processes ranging from growth, development to stress responses and even cell death. Our result showed that salinity alone significantly suppressed the transcripts of BAG6, BAG7 and addition of ACC in the saline solution could obviously re-activate BAG6 and BAG7 expressions, which might play a key role to inhibit the salt-induced cell death. In summary, our research implies that ethylene and salinity antagonistically control BAG family-, ethylene-, and senescence-related genes to alleviate the salt-induced cell death.

  9. Arabidopsis STO/BBX24 negatively regulates UV-B signaling by interacting with COP1 and repressing HY5 transcriptional activity

    Institute of Scientific and Technical Information of China (English)

    Lei Jiang; Yan Wang; Qian-Feng Li; Lars Olof Bj(o)rn; Jun-Xian He; Shao-Shan Li

    2012-01-01

    UV-B (280-315 nm) is an integral part of solar radiation and can act either as a stress inducer or as a developmental signal.In recent years,increasing attention has been paid to the Iow-fluence UV-B-induced photomorphogenic response and several key players in this response have been identified,which include UVR8 (a UV-B-specific photoreceptor),COPI (a WD40-repeat-containing RING finger protein),HY5 (a basic zipper transcription factor),and RUP1/2 (two UVR8-interacting proteins).Here we report that Arabidopsis SALT TOLERANCE (STO/BBX24),a known regulator for light signaling in plants,defines a new signaling component in UV-B-mediated photomorphogenesis.The bbx24 mutant is hypersensitive to UV-B radiation and becomes extremely dwarfed under UV-B treatment.By contrast,BBX24 overexpression transgenic lines respond much more weakly to UV-B than the bbx24 and wild-type plants.BBX24 expression is UV-B-inducible and its accumulation under UV-B requires COP1.Co-immunoprecipitation experiments indicate that BBX24 interacts with COP1 in planta upon UV-B illumination.Moreover,BBX24 interacts with HY5 and acts antagonistically with HY5 in UV-B-induced inhibition of hypocotyl elongation.Furthermore,BBX24 attenuates UV-B-induced HY5 accumulation and suppresses its transcription-activation activity.Taken together,our results reveal a previously uncharacterized function of the light-regulated BBX24 in UV-B responses and demonstrate that BBX24 functions as a negative regulator of photomorphogenic UV-B responses by interacting with both COP1 and HY5.The UV-B-inducible expression pattern and its suppression of HY5 activity suggest that BBX24 could be a new component of the feedback regulatory module of UV-B signaling in plants.

  10. Characterization of three Arabidopsis AP2/EREBP family transcription factors involved in ABA sensitivity,freeze and salt tolerance

    Institute of Scientific and Technical Information of China (English)

    MEI WenQian; LEI Juan; Xu Yu; WEI Gang; ZHU YuXian

    2007-01-01

    AP2/EREBP transcription factors (TFs) play very important roles in plant development,hormonal regulation and stress response. Upon genome-wide cDNA cloning,phylogenetic and expression pattern analyses of this plant specific TF family,we found that three of the members including At1g71450,At1g50680 and At5g13910,were likely involved in responses to ABA,cold and salt. Complementary DNAs containing putative full-length ORFs of these three TFs were obtained and fused individually to the GAL4 DNA-binding domains. All the 3 genes functioned effectively as trans-activators using yeast one-hybrid assays. RT-PCR experiments showed that the At1g71450 gene was induced by ABA and low temperature; the At1g50680 gene was responsive to quite a few stress conditions,but especially to freezing temperature; and the At5g13910 gene was induced by high salt treatment,drought and ethylene. By searching the ABRC T-DNA insertion mutant stocks,we obtained knockout lines for these TFs. Homozygous ko1 (At1g71450) plants showed a hypersensitive response to ABA during seed germination and also in stomata movement. Homozygous ko2 (At1g50680) plants showed a significant reduction in plant freezing tolerance compared to the wild type after chilling treatment. Homozygous ko3 (At5g13910) were less tolerant to high salinity than wild type plants. Our data suggest that At1g71450 is a negative regulator in ABA signaling,while At1g50680 and At5g13910 are positive regulators in cold and salt stress responses,respectively.

  11. The endophytic fungus Piriformospora indica stimulates the expression of nitrate reductase and the starch-degrading enzyme glucan-water dikinase in tobacco and Arabidopsis roots through a homeodomain transcription factor that binds to a conserved motif in their promoters.

    Science.gov (United States)

    Sherameti, Irena; Shahollari, Bationa; Venus, Yvonne; Altschmied, Lothar; Varma, Ajit; Oelmüller, Ralf

    2005-07-15

    Piriformospora indica, an endophytic fungus of the Sebacinaceae family, promotes growth of Arabidopsis and tobacco seedlings and stimulates nitrogen accumulation and the expression of the genes for nitrate reductase and the starch-degrading enzyme glucan-water dikinase (SEX1) in roots. Neither growth promotion nor stimulation of the two enzymes requires heterotrimeric G proteins. P. indica also stimulates the expression of the uidA gene under the control of the Arabidopsis nitrate reductase (Nia2) promoter in transgenic tobacco seedlings. At least two regions (-470/-439 and -103/-89) are important for Nia2 promoter activity in tobacco roots. One of the regions contains an element, ATGATAGATAAT, that binds to a homeodomain transcription factor in vitro. The message for this transcription factor is up-regulated by P. indica. The transcription factor also binds to a CTGATAGATCT segment in the SEX1 promoter in vitro. We propose that the growth-promoting effect initiated by P. indica is accompanied by a co-regulated stimulation of enzymes involved in nitrate and starch metabolisms.

  12. Gravitational and magnetic field variations synergize to cause subtle variations in the global transcriptional state of Arabidopsis in vitro callus cultures

    Directory of Open Access Journals (Sweden)

    Manzano Ana I

    2012-03-01

    Full Text Available Abstract Background Biological systems respond to changes in both the Earth's magnetic and gravitational fields, but as experiments in space are expensive and infrequent, Earth-based simulation techniques are required. A high gradient magnetic field can be used to levitate biological material, thereby simulating microgravity and can also create environments with a reduced or an enhanced level of gravity (g, although special attention should be paid to the possible effects of the magnetic field (B itself. Results Using diamagnetic levitation, we exposed Arabidopsis thaliana in vitro callus cultures to five environments with different levels of effective gravity and magnetic field strengths. The environments included levitation, i.e. simulated μg* (close to 0 g* at B = 10.1 T, intermediate g* (0.1 g* at B = 14.7 T and enhanced gravity levels (1.9 g* at B = 14.7 T and 2 g* at B = 10.1 T plus an internal 1 g* control (B = 16.5 T. The asterisk denotes the presence of the background magnetic field, as opposed to the effective gravity environments in the absence of an applied magnetic field, created using a Random Position Machine (simulated μg and a Large Diameter Centrifuge (2 g. Microarray analysis indicates that changes in the overall gene expression of cultured cells exposed to these unusual environments barely reach significance using an FDR algorithm. However, it was found that gravitational and magnetic fields produce synergistic variations in the steady state of the transcriptional profile of plants. Transcriptomic results confirm that high gradient magnetic fields (i.e. to create μg* and 2 g* conditions have a significant effect, mainly on structural, abiotic stress genes and secondary metabolism genes, but these subtle gravitational effects are only observable using clustering methodologies. Conclusions A detailed microarray dataset analysis, based on clustering of similarly expressed genes (GEDI software, can detect underlying global

  13. Hydrogen Peroxide-induced Cell Death in Arabidopsis : Transcriptional and Mutant Analysis Reveals a Role of an Oxoglutarate-dependent Dioxygenase Gene in the Cell Death Process

    NARCIS (Netherlands)

    Gechev, Tsanko S.; Minkov, Ivan N.; Hille, Jacques

    2005-01-01

    Hydrogen peroxide is a major regulator of plant programmed cell death (PCD) but little is known about the downstream genes from the H2O2-signaling network that mediate the cell death. To address this question, a novel system for studying H2O2-induced programmed cell death in Arabidopsis thaliana was

  14. Reference: 710 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available n factor family in Arabidopsis (Arabidopsis thaliana). Treatment with abscisic acid (ABA) induced AtMYB44 tr...anscript accumulation within 30 min. The gene was also activated under various abiotic stre...sses, such as dehydration, low temperature, and salinity. In transgenic Arabidopsis carrying an At...MYB44 promoter-driven beta-glucuronidase (GUS) construct, strong GUS activity was observed in the vasculature... and leaf epidermal guard cells. Transgenic Arabidopsis overexpressing AtMYB44 is more

  15. Overexpression of Grain Amaranth (Amaranthus hypochondriacus) AhERF or AhDOF Transcription Factors in Arabidopsis thaliana Increases Water Deficit- and Salt-Stress Tolerance, Respectively, via Contrasting Stress-Amelioration Mechanisms

    Science.gov (United States)

    Massange-Sánchez, Julio A.; Palmeros-Suárez, Paola A.; Espitia-Rangel, Eduardo; Rodríguez-Arévalo, Isaac; Sánchez-Segura, Lino; Martínez-Gallardo, Norma A.; Alatorre-Cobos, Fulgencio; Tiessen, Axel; Délano-Frier, John P.

    2016-01-01

    Two grain amaranth transcription factor (TF) genes were overexpressed in Arabidopsis plants. The first, coding for a group VII ethylene response factor TF (i.e., AhERF-VII) conferred tolerance to water-deficit stress (WS) in transgenic Arabidopsis without affecting vegetative or reproductive growth. A significantly lower water-loss rate in detached leaves coupled to a reduced stomatal opening in leaves of plants subjected to WS was associated with this trait. WS tolerance was also associated with an increased antioxidant enzyme activity and the accumulation of putative stress-related secondary metabolites. However, microarray and GO data did not indicate an obvious correlation between WS tolerance, stomatal closure, and abscisic acid (ABA)-related signaling. This scenario suggested that stomatal closure during WS in these plants involved ABA-independent mechanisms, possibly involving reactive oxygen species (ROS). WS tolerance may have also involved other protective processes, such as those employed for methyl glyoxal detoxification. The second, coding for a class A and cluster I DNA binding with one finger TF (i.e., AhDof-AI) provided salt-stress (SS) tolerance with no evident fitness penalties. The lack of an obvious development-related phenotype contrasted with microarray and GO data showing an enrichment of categories and genes related to developmental processes, particularly flowering. SS tolerance also correlated with increased superoxide dismutase activity but not with augmented stomatal closure. Additionally, microarray and GO data indicated that, contrary to AhERF-VII, SS tolerance conferred by AhDof-AI in Arabidopsis involved ABA-dependent and ABA-independent stress amelioration mechanisms. PMID:27749893

  16. Genome-Wide Mapping of Uncapped and Cleaved Transcripts Reveals a Role for the Nuclear mRNA Cap-Binding Complex in Cotranslational RNA Decay in Arabidopsis[OPEN

    Science.gov (United States)

    Willmann, Matthew R.

    2016-01-01

    RNA turnover is necessary for controlling proper mRNA levels posttranscriptionally. In general, RNA degradation is via exoribonucleases that degrade RNA either from the 5′ end to the 3′ end, such as XRN4, or in the opposite direction by the multisubunit exosome complex. Here, we use genome-wide mapping of uncapped and cleaved transcripts to reveal the global landscape of cotranslational mRNA decay in the Arabidopsis thaliana transcriptome. We found that this process leaves a clear three nucleotide periodicity in open reading frames. This pattern of cotranslational degradation is especially evident near the ends of open reading frames, where we observe accumulation of cleavage events focused 16 to 17 nucleotides upstream of the stop codon because of ribosomal pausing during translation termination. Following treatment of Arabidopsis plants with the translation inhibitor cycloheximide, cleavage events accumulate 13 to 14 nucleotides upstream of the start codon where initiating ribosomes have been stalled with these sequences in their P site. Further analysis in xrn4 mutant plants indicates that cotranslational RNA decay is XRN4 dependent. Additionally, studies in plants lacking CAP BINDING PROTEIN80/ABA HYPERSENSITIVE1, the largest subunit of the nuclear mRNA cap binding complex, reveal a role for this protein in cotranslational decay. In total, our results demonstrate the global prevalence and features of cotranslational RNA decay in a plant transcriptome. PMID:27758893

  17. Characterization and Ectopic Expression of CoWRI1, an AP2/EREBP Domain-Containing Transcription Factor from Coconut (Cocos nucifera L.) Endosperm, Changes the Seeds Oil Content in Transgenic Arabidopsis thaliana and Rice (Oryza sativa L.)

    Science.gov (United States)

    Sun, RuHao; Ye, Rongjian; Gao, Lingchao; Zhang, Lin; Wang, Rui; Mao, Ting; Zheng, Yusheng; Li, Dongdong; Lin, Yongjun

    2017-01-01

    Coconut (Cocos nucifera L.) is a key tropical crop and a member of the monocotyledonous family Arecaceae (Palmaceae). Few genes and related metabolic processes involved in coconut endosperm development have been investigated. In this study, a new member of the WRI1 gene family was isolated from coconut endosperm and was named CoWRI1. Its transcriptional activities and interactions with the acetyl-CoA carboxylase (BCCP2) promoter of CoWRI1 were confirmed by the yeast two-hybrid and yeast one-hybrid approaches, respectively. Functional characterization was carried out through seed-specific expression in Arabidopsis and endosperm-specific expression in rice. In transgenic Arabidopsis, high over-expressions of CoWRI1 in seven independent T2 lines were detected by quantitative real-time PCR. The relative mRNA accumulation of genes encoding enzymes involved in either fatty acid biosynthesis or triacylglycerols assembly (BCCP2, KASI, MAT, ENR, FATA, and GPDH) were also assayed in mature seeds. Furthermore, lipid and fatty acids C16:0 and C18:0 significantly increased. In two homozygous T2 transgenic rice lines (G5 and G2), different CoWRI1 expression levels were detected, but no CoWRI1 transcripts were detected in the wild type. Analyses of the seed oil content, starch content, and total protein content indicated that the two T2 transgenic lines showed a significant increase (P < 0.05) in seed oil content. The transgenic lines also showed a significant increase in starch content, whereas total protein content decreased significantly. Further analysis of the fatty acid composition revealed that palmitic acid (C16:0) and linolenic acid (C18:3) increased significantly in the seeds of the transgenic rice lines, but oleic acid (C18:1) levels significantly declined. PMID:28179911

  18. Characterization and Ectopic Expression of CoWRI1, an AP2/EREBP Domain-Containing Transcription Factor from Coconut (Cocos nucifera L.) Endosperm, Changes the Seeds Oil Content in Transgenic Arabidopsis thaliana and Rice (Oryza sativa L.).

    Science.gov (United States)

    Sun, RuHao; Ye, Rongjian; Gao, Lingchao; Zhang, Lin; Wang, Rui; Mao, Ting; Zheng, Yusheng; Li, Dongdong; Lin, Yongjun

    2017-01-01

    Coconut (Cocos nucifera L.) is a key tropical crop and a member of the monocotyledonous family Arecaceae (Palmaceae). Few genes and related metabolic processes involved in coconut endosperm development have been investigated. In this study, a new member of the WRI1 gene family was isolated from coconut endosperm and was named CoWRI1. Its transcriptional activities and interactions with the acetyl-CoA carboxylase (BCCP2) promoter of CoWRI1 were confirmed by the yeast two-hybrid and yeast one-hybrid approaches, respectively. Functional characterization was carried out through seed-specific expression in Arabidopsis and endosperm-specific expression in rice. In transgenic Arabidopsis, high over-expressions of CoWRI1 in seven independent T2 lines were detected by quantitative real-time PCR. The relative mRNA accumulation of genes encoding enzymes involved in either fatty acid biosynthesis or triacylglycerols assembly (BCCP2, KASI, MAT, ENR, FATA, and GPDH) were also assayed in mature seeds. Furthermore, lipid and fatty acids C16:0 and C18:0 significantly increased. In two homozygous T2 transgenic rice lines (G5 and G2), different CoWRI1 expression levels were detected, but no CoWRI1 transcripts were detected in the wild type. Analyses of the seed oil content, starch content, and total protein content indicated that the two T2 transgenic lines showed a significant increase (P < 0.05) in seed oil content. The transgenic lines also showed a significant increase in starch content, whereas total protein content decreased significantly. Further analysis of the fatty acid composition revealed that palmitic acid (C16:0) and linolenic acid (C18:3) increased significantly in the seeds of the transgenic rice lines, but oleic acid (C18:1) levels significantly declined.

  19. A novel Zea mays ssp. mexicana L. MYC-type ICE-like transcription factor gene ZmmICE1, enhances freezing tolerance in transgenic Arabidopsis thaliana.

    Science.gov (United States)

    Lu, Xiang; Yang, Lei; Yu, Mengyuan; Lai, Jianbin; Wang, Chao; McNeil, David; Zhou, Meixue; Yang, Chengwei

    2017-04-01

    The annual Zea mays ssp. mexicana L., a member of the teosinte group, is a close wild relative of maize and thus can be effectively used in maize improvement. In this study, an ICE-like gene, ZmmICE1, was isolated from a cDNA library of RNA-Seq from cold-treated seedling tissues of Zea mays ssp. mexicana L. The deduced protein of ZmmICE1 contains a highly conserved basic helix-loop-helix (bHLH) domain and C-terminal region of ICE-like proteins. The ZmmICE1 protein localizes to the nucleus and shows sumoylation when expressed in an Escherichia coli reconstitution system. In addition, yeast one hybrid assays indicated that ZmmICE1 has transactivation activities. Moreover, ectopic expression of ZmmICE1 in the Arabidopsis ice1-2 mutant increased freezing tolerance. The ZmmICE1 overexpressed plants showed lower electrolyte leakage (EL), reduced contents of malondialdehyde (MDA). The expression of downstream cold related genes of Arabidopsis C-repeat-binding factors (AtCBF1, AtCBF2 and AtCBF3), cold-responsive genes (AtCOR15A and AtCOR47), kinesin-1 member gene (AtKIN1) and responsive to desiccation gene (AtRD29A) was significantly induced when compared with wild type under low temperature treatment. Taken together, these results indicated that ZmmICE1 is the homolog of Arabidopsis inducer of CBF expression genes (AtICE1/2) and plays an important role in the regulation of freezing stress response.

  20. The functional interplay between protein kinase CK2 and CCA1 transcriptional activity is essential for clock temperature compensation in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Sergi Portolés

    2010-11-01

    Full Text Available Circadian rhythms are daily biological oscillations driven by an endogenous mechanism known as circadian clock. The protein kinase CK2 is one of the few clock components that is evolutionary conserved among different taxonomic groups. CK2 regulates the stability and nuclear localization of essential clock proteins in mammals, fungi, and insects. Two CK2 regulatory subunits, CKB3 and CKB4, have been also linked with the Arabidopsis thaliana circadian system. However, the biological relevance and the precise mechanisms of CK2 function within the plant clockwork are not known. By using ChIP and Double-ChIP experiments together with in vivo luminescence assays at different temperatures, we were able to identify a temperature-dependent function for CK2 modulating circadian period length. Our study uncovers a previously unpredicted mechanism for CK2 antagonizing the key clock regulator CIRCADIAN CLOCK-ASSOCIATED 1 (CCA1. CK2 activity does not alter protein accumulation or subcellular localization but interferes with CCA1 binding affinity to the promoters of the oscillator genes. High temperatures enhance the CCA1 binding activity, which is precisely counterbalanced by the CK2 opposing function. Altering this balance by over-expression, mutation, or pharmacological inhibition affects the temperature compensation profile, providing a mechanism by which plants regulate circadian period at changing temperatures. Therefore, our study establishes a new model demonstrating that two opposing and temperature-dependent activities (CCA1-CK2 are essential for clock temperature compensation in Arabidopsis.

  1. Arabidopsis HIT4, a regulator involved in heat-triggered reorganization of chromatin and release of transcriptional gene silencing, relocates from chromocenters to the nucleolus in response to heat stress.

    Science.gov (United States)

    Wang, Lian-Chin; Wu, Jia-Rong; Hsu, Yi-Ju; Wu, Shaw-Jye

    2015-01-01

    Arabidopsis HIT4 is known to mediate heat-induced decondensation of chromocenters and release from transcriptional gene silencing (TGS) with no change in the level of DNA methylation. It is unclear whether HIT4 and MOM1, a well-known DNA methylation-independent transcriptional silencer, have overlapping regulatory functions. A hit4-1/mom1 double mutant strain was generated. Its nuclear morphology and TGS state were compared with those of wild-type, hit4-1, and mom1 plants. Fluorescent protein tagging was employed to track the fates of HIT4, hit4-1 and MOM1 in vivo under heat stress. HIT4- and MOM1-mediated TGS were distinguishable. Both HIT4 and MOM1 were localized normally to chromocenters. Under heat stress, HIT4 relocated to the nucleolus, whereas MOM1 dispersed with the chromocenters. hit4-1 was able to relocate to the nucleolus under heat stress, but its relocation was insufficient to trigger the decompaction of chromocenters. The hypersensitivity to heat associated with the impaired reactivation of TGS in hit4-1 was not alleviated by mom1-induced release from TGS. HIT4 delineates a novel and MOM1-independent TGS regulation pathway. The involvement of a currently unidentified component that links HIT4 relocation and the large-scale reorganization of chromatin, and which is essential for heat tolerance in plants is hypothesized.

  2. Physiological, biochemical, and genome-wide transcriptional analysis reveals that elevated CO2 mitigates the impact of combined heat wave and drought stress in Arabidopsis thaliana at multiple organizational levels.

    Science.gov (United States)

    Zinta, Gaurav; AbdElgawad, Hamada; Domagalska, Malgorzata A; Vergauwen, Lucia; Knapen, Dries; Nijs, Ivan; Janssens, Ivan A; Beemster, Gerrit T S; Asard, Han

    2014-12-01

    Climate changes increasingly threaten plant growth and productivity. Such changes are complex and involve multiple environmental factors, including rising CO2 levels and climate extreme events. As the molecular and physiological mechanisms underlying plant responses to realistic future climate extreme conditions are still poorly understood, a multiple organizational level analysis (i.e. eco-physiological, biochemical, and transcriptional) was performed, using Arabidopsis exposed to incremental heat wave and water deficit under ambient and elevated CO2 . The climate extreme resulted in biomass reduction, photosynthesis inhibition, and considerable increases in stress parameters. Photosynthesis was a major target as demonstrated at the physiological and transcriptional levels. In contrast, the climate extreme treatment induced a protective effect on oxidative membrane damage, most likely as a result of strongly increased lipophilic antioxidants and membrane-protecting enzymes. Elevated CO2 significantly mitigated the negative impact of a combined heat and drought, as apparent in biomass reduction, photosynthesis inhibition, chlorophyll fluorescence decline, H2 O2 production, and protein oxidation. Analysis of enzymatic and molecular antioxidants revealed that the stress-mitigating CO2 effect operates through up-regulation of antioxidant defense metabolism, as well as by reduced photorespiration resulting in lowered oxidative pressure. Therefore, exposure to future climate extreme episodes will negatively impact plant growth and production, but elevated CO2 is likely to mitigate this effect.

  3. The Metabolic Response of Arabidopsis Roots to Oxidative Stress is Distinct from that of Heterotrophic Cells in Culture and Highlights a Complex Relationship between the Levels of Transcripts,Metabolites,and Flux

    Institute of Scientific and Technical Information of China (English)

    Martin Lehmann; Markus Schwarzl(a)inder; Toshihiro Obata; Supaart Sirikantaramas; Meike Burow; Carl Erik Olsen; Takayuki Tohge; Mark D.Fricker; Birger Lindberg Mφller; Alisdair R.Fernie; Lee J.Sweetloveb; Miriam Laxa

    2009-01-01

    Metabolic adjustments are a significant,but poorly understood,part of the response of plants to oxidative stress.In a previous study (Baxter et al.,2007),the metabolic response of Arabidopsis cells in culture to induction of ox-idative stress by menadione was characterized.An emergency survival strategy was uncovered in which anabolic primary metabolism was largely down-regulated in favour of catabolic and antioxidant metabolism.The response in whole plant tissues may be different and we have therefore investigated the response of Arabidopsis roots to menadione treatment,analyzing the transcriptome,metabolome and key metabolic fluxes with focus on primary as well as secondary metab-olism.Using a redox-sensitive GFP,it was also shown that menadione causes redox perturbation,not just in the mitochon-drion,but also in the cytosol and plastids of roots.In the first 30 min of treatment,the response was similar to the cell culture:there was a decrease in metabolites of the TCA cycle and amino acid biosynthesis and the transcriptomic response was dominated by up-regulation of DNA regulatory proteins.After 2 and 6 h of treatment,the response of the roots was different to the cell culture.Metabolite levels did not remain depressed,but instead recovered and,in the case of pyruvate,some amino acids and aliphatic glucosinolates showed a steady increase above control levels.However,no major changes in fluxes of central carbon metabolism were observed and metabolic transcripts changed largely independently of the corresponding metabolites.Together,the results suggest that root tissues can recover metabolic activity after oxidative inhibition and highlight potentially important roles for glycolysis and the oxidative pentose phosphate pathway.

  4. Arabidopsis CDS blastp result: AK318617 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK318617 J100090H20 At1g19850.1 68414.m02490 transcription factor MONOPTEROS (MP) /... auxin-responsive protein (IAA24) / auxin response factor 5 (ARF5) identical to transcription factor MONOPTEROS (MP/IAA24/ARF5) SP:P93024 from [Arabidopsis thaliana] 2e-63 ...

  5. Arabidopsis CDS blastp result: AK103452 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK103452 J033129I11 At1g19850.1 transcription factor MONOPTEROS (MP) / auxin-respon...sive protein (IAA24) / auxin response factor 5 (ARF5) identical to transcription factor MONOPTEROS (MP/IAA24/ARF5) SP:P93024 from [Arabidopsis thaliana] 1e-166 ...

  6. Arabidopsis CDS blastp result: AK243230 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK243230 J100044L04 At1g19850.1 68414.m02490 transcription factor MONOPTEROS (MP) /... auxin-responsive protein (IAA24) / auxin response factor 5 (ARF5) identical to transcription factor MONOPTEROS (MP/IAA24/ARF5) SP:P93024 from [Arabidopsis thaliana] 2e-65 ...

  7. Arabidopsis CDS blastp result: AK243428 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK243428 J100067L15 At5g14750.1 68418.m01731 myb family transcription factor (MYB66) / werewolf...iption factor (MYB66) mRNA, partial cds GI:3941491; identical to GP:9755743 myb transcription factor werewolf (WER)/ MYB66 {Arabidopsis thaliana} 8e-36 ...

  8. Arabidopsis CDS blastp result: AK288699 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK288699 J090061C22 At5g14750.1 68418.m01731 myb family transcription factor (MYB66) / werewolf...iption factor (MYB66) mRNA, partial cds GI:3941491; identical to GP:9755743 myb transcription factor werewolf (WER)/ MYB66 {Arabidopsis thaliana} 8e-36 ...

  9. Arabidopsis CDS blastp result: AK243271 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK243271 J100049K04 At5g14750.1 68418.m01731 myb family transcription factor (MYB66) / werewolf...iption factor (MYB66) mRNA, partial cds GI:3941491; identical to GP:9755743 myb transcription factor werewolf (WER)/ MYB66 {Arabidopsis thaliana} 4e-35 ...

  10. Arabidopsis CDS blastp result: AK241812 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK241812 J065210K15 At5g14750.1 68418.m01731 myb family transcription factor (MYB66) / werewolf...iption factor (MYB66) mRNA, partial cds GI:3941491; identical to GP:9755743 myb transcription factor werewolf (WER)/ MYB66 {Arabidopsis thaliana} 1e-22 ...

  11. Arabidopsis CDS blastp result: AK241549 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK241549 J065176M15 At5g14750.1 68418.m01731 myb family transcription factor (MYB66) / werewolf...iption factor (MYB66) mRNA, partial cds GI:3941491; identical to GP:9755743 myb transcription factor werewolf (WER)/ MYB66 {Arabidopsis thaliana} 3e-32 ...

  12. Arabidopsis CDS blastp result: AK241615 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK241615 J065186D02 At5g14750.1 68418.m01731 myb family transcription factor (MYB66) / werewolf...iption factor (MYB66) mRNA, partial cds GI:3941491; identical to GP:9755743 myb transcription factor werewolf (WER)/ MYB66 {Arabidopsis thaliana} 8e-35 ...

  13. Arabidopsis CDS blastp result: AK288487 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK288487 J090040H24 At5g14750.1 68418.m01731 myb family transcription factor (MYB66) / werewolf...iption factor (MYB66) mRNA, partial cds GI:3941491; identical to GP:9755743 myb transcription factor werewolf (WER)/ MYB66 {Arabidopsis thaliana} 5e-37 ...

  14. Arabidopsis CDS blastp result: AK287469 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK287469 J043021L20 At5g14750.1 68418.m01731 myb family transcription factor (MYB66) / werewolf...iption factor (MYB66) mRNA, partial cds GI:3941491; identical to GP:9755743 myb transcription factor werewolf (WER)/ MYB66 {Arabidopsis thaliana} 2e-36 ...

  15. Arabidopsis CDS blastp result: AK241370 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK241370 J065154C10 At5g14750.1 68418.m01731 myb family transcription factor (MYB66) / werewolf...iption factor (MYB66) mRNA, partial cds GI:3941491; identical to GP:9755743 myb transcription factor werewolf (WER)/ MYB66 {Arabidopsis thaliana} 2e-31 ...

  16. Arabidopsis CDS blastp result: AK288415 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK288415 J090031E07 At5g14750.1 68418.m01731 myb family transcription factor (MYB66) / werewolf...iption factor (MYB66) mRNA, partial cds GI:3941491; identical to GP:9755743 myb transcription factor werewolf (WER)/ MYB66 {Arabidopsis thaliana} 3e-37 ...

  17. Bioinformatic cis-element analyses performed in Arabidopsis and rice disclose bZIP- and MYB-related binding sites as potential AuxRE-coupling elements in auxin-mediated transcription

    Directory of Open Access Journals (Sweden)

    Berendzen Kenneth W

    2012-08-01

    Full Text Available Abstract Background In higher plants, a diverse array of developmental and growth-related processes is regulated by the plant hormone auxin. Recent publications have proposed that besides the well-characterized Auxin Response Factors (ARFs that bind Auxin Response Elements (AuxREs, also members of the bZIP- and MYB-transcription factor (TF families participate in transcriptional control of auxin-regulated genes via bZIP Response Elements (ZREs or Myb Response Elements (MREs, respectively. Results Applying a novel bioinformatic algorithm, we demonstrate on a genome-wide scale that singular motifs or composite modules of AuxREs, ZREs, MREs but also of MYC2 related elements are significantly enriched in promoters of auxin-inducible genes. Despite considerable, species-specific differences in the genome structure in terms of the GC content, this enrichment is generally conserved in dicot (Arabidopsis thaliana and monocot (Oryza sativa model plants. Moreover, an enrichment of defined composite modules has been observed in selected auxin-related gene families. Consistently, a bipartite module, which encompasses a bZIP-associated G-box Related Element (GRE and an AuxRE motif, has been found to be highly enriched. Making use of transient reporter studies in protoplasts, these findings were experimentally confirmed, demonstrating that GREs functionally interact with AuxREs in regulating auxin-mediated transcription. Conclusions Using genome-wide bioinformatic analyses, evolutionary conserved motifs have been defined which potentially function as AuxRE-dependent coupling elements to establish auxin-specific expression patterns. Based on these findings, experimental approaches can be designed to broaden our understanding of combinatorial, auxin-controlled gene regulation.

  18. A single amino acid substitution in IIIf subfamily of basic helix-loop-helix transcription factor AtMYC1 leads to trichome and root hair patterning defects by abolishing its interaction with partner proteins in Arabidopsis.

    Science.gov (United States)

    Zhao, Hongtao; Wang, Xiaoxue; Zhu, Dandan; Cui, Sujuan; Li, Xia; Cao, Ying; Ma, Ligeng

    2012-04-20

    Plant trichomes and root hairs are powerful models for the study of cell fate determination. In Arabidopsis thaliana, trichome and root hair initiation requires a combination of three groups of proteins, including the WD40 repeat protein transparent TESTA GLABRA1 (TTG1), R2R3 repeat MYB protein GLABRA1 (GL1), or werewolf (WER) and the IIIf subfamily of basic helix-loop-helix (bHLH) protein GLABRA3 (GL3) or enhancer of GLABRA3 (EGL3). The bHLH component acts as a docking site for TTG1 and MYB proteins. Here, we isolated a mutant showing defects in trichome and root hair patterning that carried a point mutation (R173H) in AtMYC1 that encodes the fourth member of IIIf bHLH family protein. Genetic analysis revealed partial redundant yet distinct function between AtMYC1 and GL3/EGL3. GLABRA2 (GL2), an important transcription factor involved in trichome and root hair control, was down-regulated in Atmyc1 plants, suggesting the requirement of AtMYC1 for appropriate GL2 transcription. Like its homologs, AtMYC1 formed a complex with TTG1 and MYB proteins but did not dimerized. In addition, the interaction of AtMYC1 with MYB proteins and TTG1 was abrogated by the R173H substitution in Atmyc1-1. We found that this amino acid (Arg) is conserved in the AtMYC1 homologs GL3/EGL3 and that it is essential for their interaction with MYB proteins and for their proper functions. Our findings indicate that AtMYC1 is an important regulator of trichome and root hair initiation, and they reveal a novel amino acid necessary for protein-protein interactions and gene function in IIIf subfamily bHLH transcription factors.

  19. AtCCR4a and AtCCR4b are Involved in Determining the Poly(A) Length of Granule-bound starch synthase 1 Transcript and Modulating Sucrose and Starch Metabolism in Arabidopsis thaliana.

    Science.gov (United States)

    Suzuki, Yuya; Arae, Toshihiro; Green, Pamela J; Yamaguchi, Junji; Chiba, Yukako

    2015-05-01

    Removing the poly(A) tail is the first and rate-limiting step of mRNA degradation and apparently an effective step not only for modulating mRNA stability but also for translation of many eukaryotic transcripts. Carbon catabolite repressor 4 (CCR4) has been identified as a major cytoplasmic deadenylase in Saccharomyces cerevisiae. The Arabidopsis thaliana homologs of the yeast CCR4, AtCCR4a and AtCCR4b, were identified by sequence-based analysis; however, their role and physiological significance in plants remain to be elucidated. In this study, we revealed that AtCCR4a and AtCCR4b are localized to cytoplasmic mRNA processing bodies, which are specific granules consisting of many enzymes involved in mRNA turnover. Double mutants of AtCCR4a and AtCCR4b exhibited tolerance to sucrose application but not to glucose. The levels of sucrose in the seedlings of the atccr4a/4b double mutants were reduced, whereas no difference was observed in glucose levels. Further, amylose levels were slightly but significantly increased in the atccr4a/4b double mutants. Consistent with this observation, we found that the transcript encoding granule-bound starch synthase 1 (GBSS1), which is responsible for amylose synthesis, is accumulated to a higher level in the atccr4a/4b double mutant plants than in the control plants. Moreover, we revealed that GBSS1 has a longer poly(A) tail in the double mutant than in the control plant, suggesting that AtCCR4a and AtCCR4b can influence the poly(A) length of transcripts related to starch metabolism. Our results collectively suggested that AtCCR4a and AtCCR4b are involved in sucrose and starch metabolism in A. thaliana.

  20. MicroRNA directs mRNA cleavage of the transcription factor NAC1 to downregulate auxin signals for arabidopsis lateral root development.

    Science.gov (United States)

    Guo, Hui-Shan; Xie, Qi; Fei, Ji-Feng; Chua, Nam-Hai

    2005-05-01

    Although several plant microRNAs (miRNAs) have been shown to play a role in plant development, no phenotype has yet been associated with a reduction or loss of expression of any plant miRNA. Arabidopsis thaliana miR164 was predicted to target five NAM/ATAF/CUC (NAC) domain-encoding mRNAs, including NAC1, which transduces auxin signals for lateral root emergence. Here, we show that miR164 guides the cleavage of endogenous and transgenic NAC1 mRNA, producing 3'-specific fragments. Cleavage was blocked by NAC1 mutations that disrupt base pairing with miR164. Compared with wild-type plants, Arabidopsis mir164a and mir164b mutant plants expressed less miR164 and more NAC1 mRNA and produced more lateral roots. These mutant phenotypes can be complemented by expression of the appropriate MIR164a and MIR164b genomic sequences. By contrast, inducible expression of miR164 in wild-type plants led to decreased NAC1 mRNA levels and reduced lateral root emergence. Auxin induction of miR164 was mirrored by an increase in the NAC1 mRNA 3' fragment, which was not observed in the auxin-insensitive mutants auxin resistant1 (axr1-12), axr2-1, and transport inhibitor response1. Moreover, the cleavage-resistant form of NAC1 mRNA was unaffected by auxin treatment. Our results indicate that auxin induction of miR164 provides a homeostatic mechanism to clear NAC1 mRNA to downregulate auxin signals.

  1. Transcriptional regulation by an NAC (NAM-ATAF1,2-CUC2) transcription factor attenuates ABA signalling for efficient basal defence towards Blumeria graminis f. sp hordei in Arabidopsis

    DEFF Research Database (Denmark)

    Jensen, Michael Krogh; Hagedorn, Peter; De Torres-Zabala, Marta

    2008-01-01

    -representation of abscisic acid (ABA)-responsive genes, including the ABA biosynthesis gene AAO3, which is significantly induced in ataf1 plants compared to wild-type plants following inoculation with Bgh. Additionally, we show that Bgh inoculation results in decreased endogenous ABA levels in an ATAF1-dependent manner......, and that the ABA biosynthetic mutant aao3 showed increased penetration resistance to Bgh compared to wild-type plants. Furthermore, we show that ataf1 plants show ABA-hyposensitive phenotypes during seedling development and germination. Our data support a negative correlation between ABA levels and penetration...... resistance, and identify ATAF1 as a new stimuli-dependent attenuator of ABA signalling for the mediation of efficient penetration resistance in Arabidopsis upon Bgh attack....

  2. Ectopic Expression of the Wild Grape WRKY Transcription Factor VqWRKY52 in Arabidopsis thaliana Enhances Resistance to the Biotrophic Pathogen Powdery Mildew But Not to the Necrotrophic Pathogen Botrytis cinerea

    Science.gov (United States)

    Wang, Xianhang; Guo, Rongrong; Tu, Mingxing; Wang, Dejun; Guo, Chunlei; Wan, Ran; Li, Zhi; Wang, Xiping

    2017-01-01

    WRKY transcription factors are known to play important roles in plant responses to biotic stresses. We previously showed that the expression of the WRKY gene, VqWRKY52, from Chinese wild Vitis quinquangularis was strongly induced 24 h post inoculation with powdery mildew. In this study, we analyzed the expression levels of VqWRKY52 following treatment with the defense related hormones salicylic acid (SA) and methyl jasmonate, revealing that VqWRKY52 was strongly induced by SA but not JA. We characterized the VqWRKY52 gene, which encodes a WRKY III gene family member, and found that ectopic expression in Arabidopsis thaliana enhanced resistance to powdery mildew and Pseudomonas syringae pv. tomato DC3000, but increased susceptibility to Botrytis cinerea, compared with wild type (WT) plants. The transgenic A. thaliana lines displayed strong cell death induced by the biotrophic powdery mildew pathogen, the hemibiotrophic P. syringe pathogen and the necrotrophic pathogen B. cinerea. In addition, the relative expression levels of various defense-related genes were compared between the transgenic A. thaliana lines and WT plants following the infection by different pathogens. Collectively, the results indicated that VqWRKY52 plays essential roles in the SA dependent signal transduction pathway and that it can enhance the hypersensitive response cell death triggered by microbial pathogens. PMID:28197166

  3. Over-expression of JcDREB, a putative AP2/EREBP domain-containing transcription factor gene in woody biodiesel plant Jatropha curcas, enhances salt and freezing tolerance in transgenic Arabidopsis thaliana.

    Science.gov (United States)

    Tang, Mingjuan; Liu, Xiaofei; Deng, Huaping; Shen, Shihua

    2011-12-01

    Jatropha curcas L. is an all-purpose biodiesel plant and is widely distributed in tropical and subtropical climates. It can grow well on poor quality soil which is not qualified for crop cultivation. This is very important for relieving land, food and energy crises. However, tropical and subtropical distribution limits the production of J. curcas seed. So it is valuable to know the molecular mechanism of J. curcas response to adverse abiotic environmental factors, especially freezing stress, in order to change the plant's characteristics. Until now there are just a few reports about J. curcas molecular biology. In this paper, we cloned and characterized a DNA binding protein from this plant, designated as JcDREB. Sequence analysis and yeast one-hybrid assays show that JcDREB can effectively function as a transcription factor of DREB protein family belonging to A-6 subgroup member. Expression patterns of JcDREB showed that it was induced by cold, salt and drought stresses, not by ABA. Over-expression of JcDREB in transgenic Arabidopsis exhibited enhanced salt and freezing stresses. Understanding the molecular mechanisms of J. curcas responses to environmental stresses, for example, high salinity, drought and low temperature, is crucial for improving their stress tolerance and productivity. This work provides more information about A-6 subgroup members of DREB subfamily.

  4. Ectopic Expression of the Wild Grape WRKY Transcription Factor VqWRKY52 in Arabidopsis thaliana Enhances Resistance to the Biotrophic Pathogen Powdery Mildew But Not to the Necrotrophic Pathogen Botrytis cinerea.

    Science.gov (United States)

    Wang, Xianhang; Guo, Rongrong; Tu, Mingxing; Wang, Dejun; Guo, Chunlei; Wan, Ran; Li, Zhi; Wang, Xiping

    2017-01-01

    WRKY transcription factors are known to play important roles in plant responses to biotic stresses. We previously showed that the expression of the WRKY gene, VqWRKY52, from Chinese wild Vitis quinquangularis was strongly induced 24 h post inoculation with powdery mildew. In this study, we analyzed the expression levels of VqWRKY52 following treatment with the defense related hormones salicylic acid (SA) and methyl jasmonate, revealing that VqWRKY52 was strongly induced by SA but not JA. We characterized the VqWRKY52 gene, which encodes a WRKY III gene family member, and found that ectopic expression in Arabidopsis thaliana enhanced resistance to powdery mildew and Pseudomonas syringae pv. tomato DC3000, but increased susceptibility to Botrytis cinerea, compared with wild type (WT) plants. The transgenic A. thaliana lines displayed strong cell death induced by the biotrophic powdery mildew pathogen, the hemibiotrophic P. syringe pathogen and the necrotrophic pathogen B. cinerea. In addition, the relative expression levels of various defense-related genes were compared between the transgenic A. thaliana lines and WT plants following the infection by different pathogens. Collectively, the results indicated that VqWRKY52 plays essential roles in the SA dependent signal transduction pathway and that it can enhance the hypersensitive response cell death triggered by microbial pathogens.

  5. Arabidopsis FHY3 and FAR1 Regulate Light-Induced myo-Inositol Biosynthesis and Oxidative Stress Responses by Transcriptional Activation of MIPS1.

    Science.gov (United States)

    Ma, Lin; Tian, Tian; Lin, Rongcheng; Deng, Xing-Wang; Wang, Haiyang; Li, Gang

    2016-04-04

    myo-Inositol-1-phosphate synthase (MIPS) catalyzes the limiting step of inositol biosynthesis and has crucial roles in plant growth and development. In response to stress, the transcription of MIPS1 is induced and the biosynthesis of inositol or inositol derivatives is promoted by unknown mechanisms. Here, we found that the light signaling protein FAR-RED ELONGATED HYPOCOTYL3 (FHY3) and its homolog FAR-RED IMPAIRED RESPONSE1 (FAR1) regulate light-induced inositol biosynthesis and oxidative stress responses by activating the transcription of MIPS1. Disruption of FHY3 and FAR1 caused light-induced cell death after dark-light transition, precocious leaf senescence, and increased sensitivity to oxidative stress. Reduction of salicylic acid (SA) accumulation by overexpression of SALICYLIC ACID 3-HYDROXYLASE largely suppressed the cell death phenotype of fhy3 far1 mutant plants, suggesting that FHY3- and FAR1-mediated cell death is dependent on SA. Furthermore, comparative analysis of chromatin immunoprecipitation sequencing and microarray results revealed that FHY3 and FAR1 directly target both MIPS1 and MIPS2. The fhy3 far1 mutant plants showed severely decreased MIPS1/2 transcript levels and reduced inositol levels. Conversely, constitutive expression of MIPS1 partially rescued the inositol contents, caused reduced transcript levels of SA-biosynthesis genes, and prevented oxidative stress in fhy3 far1. Taken together, our results indicate that the light signaling proteins FHY3 and FAR1 directly bind the promoter of MIPS1 to activate its expression and thereby promote inositol biosynthesis to prevent light-induced oxidative stress and SA-dependent cell death.

  6. Comparative analysis of drought resistance genes in Arabidopsis and rice

    NARCIS (Netherlands)

    Trijatmiko, K.R.

    2005-01-01

    Keywords: rice, Arabidopsis, drought, genetic mapping,microarray, transcription factor, AP2/ERF, SHINE, wax, stomata, comparative genetics, activation tagging, Ac/Ds, En/IThis thesis describes the use of genomics information and tools from Arabidopsis and

  7. Reactive oxygen species and transcript analysis upon excess light treatment in wild-type Arabidopsis thaliana vs a photosensitive mutant lacking zeaxanthin and lutein

    Directory of Open Access Journals (Sweden)

    Roncaglia Enrica

    2011-04-01

    Full Text Available Abstract Background Reactive oxygen species (ROS are unavoidable by-products of oxygenic photosynthesis, causing progressive oxidative damage and ultimately cell death. Despite their destructive activity they are also signalling molecules, priming the acclimatory response to stress stimuli. Results To investigate this role further, we exposed wild type Arabidopsis thaliana plants and the double mutant npq1lut2 to excess light. The mutant does not produce the xanthophylls lutein and zeaxanthin, whose key roles include ROS scavenging and prevention of ROS synthesis. Biochemical analysis revealed that singlet oxygen (1O2 accumulated to higher levels in the mutant while other ROS were unaffected, allowing to define the transcriptomic signature of the acclimatory response mediated by 1O2 which is enhanced by the lack of these xanthophylls species. The group of genes differentially regulated in npq1lut2 is enriched in sequences encoding chloroplast proteins involved in cell protection against the damaging effect of ROS. Among the early fine-tuned components, are proteins involved in tetrapyrrole biosynthesis, chlorophyll catabolism, protein import, folding and turnover, synthesis and membrane insertion of photosynthetic subunits. Up to now, the flu mutant was the only biological system adopted to define the regulation of gene expression by 1O2. In this work, we propose the use of mutants accumulating 1O2 by mechanisms different from those activated in flu to better identify ROS signalling. Conclusions We propose that the lack of zeaxanthin and lutein leads to 1O2 accumulation and this represents a signalling pathway in the early stages of stress acclimation, beside the response to ADP/ATP ratio and to the redox state of both plastoquinone pool. Chloroplasts respond to 1O2 accumulation by undergoing a significant change in composition and function towards a fast acclimatory response. The physiological implications of this signalling specificity are

  8. The Arabidopsis bZIP11 transcription factor links low-energy signalling to auxin-mediated control of primary root growth.

    Science.gov (United States)

    Weiste, Christoph; Pedrotti, Lorenzo; Selvanayagam, Jebasingh; Muralidhara, Prathibha; Fröschel, Christian; Novák, Ondřej; Ljung, Karin; Hanson, Johannes; Dröge-Laser, Wolfgang

    2017-02-01

    Plants have to tightly control their energy homeostasis to ensure survival and fitness under constantly changing environmental conditions. Thus, it is stringently required that energy-consuming stress-adaptation and growth-related processes are dynamically tuned according to the prevailing energy availability. The evolutionary conserved SUCROSE NON-FERMENTING1 RELATED KINASES1 (SnRK1) and the downstream group C/S1 basic leucine zipper (bZIP) transcription factors (TFs) are well-characterised central players in plants' low-energy management. Nevertheless, mechanistic insights into plant growth control under energy deprived conditions remains largely elusive. In this work, we disclose the novel function of the low-energy activated group S1 bZIP11-related TFs as regulators of auxin-mediated primary root growth. Whereas transgenic gain-of-function approaches of these bZIPs interfere with the activity of the root apical meristem and result in root growth repression, root growth of loss-of-function plants show a pronounced insensitivity to low-energy conditions. Based on ensuing molecular and biochemical analyses, we propose a mechanistic model, in which bZIP11-related TFs gain control over the root meristem by directly activating IAA3/SHY2 transcription. IAA3/SHY2 is a pivotal negative regulator of root growth, which has been demonstrated to efficiently repress transcription of major auxin transport facilitators of the PIN-FORMED (PIN) gene family, thereby restricting polar auxin transport to the root tip and in consequence auxin-driven primary root growth. Taken together, our results disclose the central low-energy activated SnRK1-C/S1-bZIP signalling module as gateway to integrate information on the plant's energy status into root meristem control, thereby balancing plant growth and cellular energy resources.

  9. Chromosomal proteins of Arabidopsis thaliana.

    Science.gov (United States)

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

    1988-07-01

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

  10. Prokaryotic Expression of the Arabidopsis Transcription Factor DYT1 and Preparation of Its Polyclonal Antibodies%拟南芥转录因子DYT1的原核表达与多克隆抗体制备

    Institute of Scientific and Technical Information of China (English)

    俞俞; 邢卫锋; 周茜

    2011-01-01

    以拟南芥雄性不育突变体ms157为材料,对其转录因子DYT1的原核表达进行了分析及多克隆抗体的制备.结果表明:构建的原核表达载体转化入BL21菌株后,经IPTG诱导,表达了分子量约为50 kD的重组蛋白.SDS-PAGE检测结果表明,该重组表达蛋白以可融性形式表达.用该蛋白作为抗原注射新西兰兔后,成功获取了多克隆抗体.Western blotting证实其具良好的免疫原性,ELISA结果表明融合蛋白的效价大于1:5 120.%With a male-sterile mutant ms157 of Arabidopsis as material,we analyzed prokaryotic expression of the transcription factor DYT1 and prepared its polyclonal antibodies. The results indicated that the recombination expression plasmid was constructed and transformed into Escherichia coli BL21 strain. The soluble DYT1 protein was induced with IPTG and used as the antigen to immune the rabbits. SDS-PAGE analysis showed that the fusion protein had relative molecular mass of 50 kD. ELISA assay demonstrated that the titer of prepared polyclonal antibody was over 1: 5 120. Additionally,the immunological specificity of polyclonal antibody was validated by Western blotting.

  11. The transcription factors MS188 and AMS form a complex to activate the expression of CYP703A2 for sporopollenin biosynthesis in Arabidopsis thaliana.

    Science.gov (United States)

    Xiong, Shuang-Xi; Lu, Jie-Yang; Lou, Yue; Teng, Xiao-Dong; Gu, Jing-Nan; Zhang, Cheng; Shi, Qiang-Sheng; Yang, Zhong-Nan; Zhu, Jun

    2016-12-01

    The sexine layer of pollen grain is mainly composed of sporopollenins. The sporophytic secretory tapetum is required for the biosynthesis of sporopollenin. Although several enzymes involved in sporopollenin biosynthesis have been reported, the regulatory mechanism of these enzymes in tapetal layer remains elusive. ABORTED MICROSPORES (AMS) and MALE STERILE 188/MYB103/MYB80 (MS188/MYB103/MYB80) are two tapetal cell-specific transcription factors required for pollen wall formation. AMS functions upstream of MS188. Here we report that AMS and MS188 target the CYP703A2 gene, which is involved in sporopollenin biosynthesis. We found that AMS and MS188 were localized in tapetum while CYP703A2 was localized in both tapetum and locule. Chromatin immunoprecipitation (ChIP) showed that MS188 directly bound to the promoter of CYP703A2 and luciferase-inducible assay showed that MS188 activated the expression of CYP703A2. Yeast two-hybrid and electrophoretic mobility shift assays (EMSAs) further demonstrated that MS188 complexed with AMS. The expression of CYP703A2 could be partially restored by the elevated levels of MS188 in the ams mutant. Therefore, our data reveal that MS188 coordinates with AMS to activate CYP703A2 in sporopollenin biosynthesis of plant tapetum.

  12. Modeling the global effect of the basic-leucine zipper transcription factor 1 (bZIP1 on nitrogen and light regulation in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Obertello Mariana

    2010-08-01

    Full Text Available Abstract Background Nitrogen and light are two major regulators of plant metabolism and development. While genes involved in the control of each of these signals have begun to be identified, regulators that integrate gene responses to nitrogen and light signals have yet to be determined. Here, we evaluate the role of bZIP1, a transcription factor involved in light and nitrogen sensing, by exposing wild-type (WT and bZIP1 T-DNA null mutant plants to a combinatorial space of nitrogen (N and light (L treatment conditions and performing transcriptome analysis. We use ANOVA analysis combined with clustering and Boolean modeling, to evaluate the role of bZIP1 in mediating L and N signaling genome-wide. Results This transcriptome analysis demonstrates that a mutation in the bZIP1 gene can alter the L and/or N-regulation of several gene clusters. More surprisingly, the bZIP1 mutation can also trigger N and/or L regulation of genes that are not normally controlled by these signals in WT plants. This analysis also reveals that bZIP1 can, to a large extent, invert gene regulation (e.g., several genes induced by N in WT plants are repressed by N in the bZIP1 mutant. Conclusion These findings demonstrate that the bZIP1 mutation triggers a genome-wide de-regulation in response to L and/or N signals that range from i a reduction of the L signal effect, to ii unlocking gene regulation in response to L and N combinations. This systems biology approach demonstrates that bZIP1 tunes L and N signaling relationships genome-wide, and can suppress regulatory mechanisms hypothesized to be needed at different developmental stages and/or environmental conditions.

  13. Transcription factor WRKY46 modulates the development of Arabidopsis lateral roots in osmotic/salt stress conditions via regulation of ABA signaling and auxin homeostasis.

    Science.gov (United States)

    Ding, Zhong Jie; Yan, Jing Ying; Li, Chun Xiao; Li, Gui Xin; Wu, Yun Rong; Zheng, Shao Jian

    2015-10-01

    The development of lateral roots (LR) is known to be severely inhibited by salt or osmotic stress. However, the molecular mechanisms underlying LR development in osmotic/salt stress conditions are poorly understood. Here we show that the gene encoding the WRKY transcription factor WRKY46 (WRKY46) is expressed throughout lateral root primordia (LRP) during early LR development and that expression is subsequently restricted to the stele of the mature LR. In osmotic/salt stress conditions, lack of WRKY46 (in loss-of-function wrky46 mutants) significantly reduces, while overexpression of WRKY46 enhances, LR development. We also show that exogenous auxin largely restores LR development in wrky46 mutants, and that the auxin transport inhibitor 2,3,5-triiodobenzoic acid (TIBA) inhibits LR development in both wild-type (WT; Col-0) and in a line overexpressing WRKY46 (OV46). Subsequent analysis of abscisic acid (ABA)-related mutants indicated that WRKY46 expression is down-regulated by ABA signaling, and up-regulated by an ABA-independent signal induced by osmotic/salt stress. Next, we show that expression of the DR5:GUS auxin response reporter is reduced in roots of wrky46 mutants, and that both wrky46 mutants and OV46 display altered root levels of free indole-3-acetic acid (IAA) and IAA conjugates. Subsequent RT-qPCR and ChIP-qPCR experiments indicated that WRKY46 directly regulates the expression of ABI4 and of genes regulating auxin conjugation. Finally, analysis of wrky46 abi4 double mutant plants confirms that ABI4 acts downstream of WRKY46. In summary, our results demonstrate that WRKY46 contributes to the feedforward inhibition of osmotic/salt stress-dependent LR inhibition via regulation of ABA signaling and auxin homeostasis.

  14. TBP-associated factors in Arabidopsis.

    Science.gov (United States)

    Lago, Clara; Clerici, Elena; Mizzi, Luca; Colombo, Lucia; Kater, Martin M

    2004-11-24

    Initiation of transcription mediated by RNA polymerase II requires a number of transcription factors among which TFIID is the major core promoter recognition factor. TFIID is composed of highly conserved factors which include the TATA-binding protein (TBP) and about 14 TBP-associated factors (TAFs). Since TAFs play important roles in transcription they have been extensively studied in organisms like yeast, Drosophila and human. Surprisingly, TAFs have been poorly characterized in plants. With the completion of the Arabidopsis genome sequence, it is possible to search for TAFs, since many of them have conserved amino acid sequences. Mining the genome of Arabidopsis for TAFs resulted in the identification of 18 putative Arabidopsis TAFs (AtTAFs). We have analyzed their protein structure and their genomic localisation. Expression profiling by RT-PCR showed that these TAFs are expressed in all parts of the plant which is in agreement with their general role in transcription. These analyses in combination with their evolutionary conservation with TAFs of other organisms are discussed.

  15. Mining the active proteome of Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Renier A. L. Van Der Hoorn

    2011-11-01

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

  16. Transcriptional and post-transcriptional regulation of a NAC1 transcription factor in Medicago truncatula roots.

    Science.gov (United States)

    D'haeseleer, Katrien; Den Herder, Griet; Laffont, Carole; Plet, Julie; Mortier, Virginie; Lelandais-Brière, Christine; De Bodt, Stefanie; De Keyser, Annick; Crespi, Martin; Holsters, Marcelle; Frugier, Florian; Goormachtig, Sofie

    2011-08-01

    • Legume roots develop two types of lateral organs, lateral roots and nodules. Nodules develop as a result of a symbiotic interaction with rhizobia and provide a niche for the bacteria to fix atmospheric nitrogen for the plant. • The Arabidopsis NAC1 transcription factor is involved in lateral root formation, and is regulated post-transcriptionally by miRNA164 and by SINAT5-dependent ubiquitination. We analyzed in Medicago truncatula the role of the closest NAC1 homolog in lateral root formation and in nodulation. • MtNAC1 shows a different expression pattern in response to auxin than its Arabidopsis homolog and no changes in lateral root number or nodulation were observed in plants affected in MtNAC1 expression. In addition, no interaction was found with SINA E3 ligases, suggesting that post-translational regulation of MtNAC1 does not occur in M. truncatula. Similar to what was found in Arabidopsis, a conserved miR164 target site was retrieved in MtNAC1, which reduced protein accumulation of a GFP-miR164 sensor. Furthermore, miR164 and MtNAC1 show an overlapping expression pattern in symbiotic nodules, and overexpression of this miRNA led to a reduction in nodule number. • This work suggests that regulatory pathways controlling a conserved transcription factor are complex and divergent between M. truncatula and Arabidopsis.

  17. Reference: 594 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available that serve as antiherbivore compounds in plant defence. A previously identified Arabidopsis thaliana activa...tion-tagged line, displaying altered levels of secondary metabolites, was shown here to be affe... by activation of the R2R3-MYB transcription factor gene HIG1 (HIGH INDOLIC GLUCOSINOLATE 1, also referred t...n of HIG1/MYB51 resulted in the specific accumulation of indolic glucosinolates without affecting auxin meta

  18. Arabidopsis CDS blastp result: AK101133 [KOME

    Lifescience Database Archive (English)

    Full Text Available F|00847 AP2 domain; identical to cDNA enhancer of shoot regeneration ESR1 GI:18028939, enhancer of shoot regeneration ESR1 [Arabidopsis thaliana] GI:18028940 1e-10 ... ...eneration (ESR1) similar to gb|D38124 EREBP-3 from Nicotiana tabacum and contains P...AK101133 J033026F23 At1g12980.1 AP2 domain-containing transcription factor, putative / enhancer of shoot reg

  19. Arabidopsis CDS blastp result: AK119645 [KOME

    Lifescience Database Archive (English)

    Full Text Available PF|00847 AP2 domain; identical to cDNA enhancer of shoot regeneration ESR1 GI:18028939, enhancer of shoot regeneration ESR1 [Arabidopsis thaliana] GI:18028940 1e-10 ... ...ve / enhancer of shoot regeneration (ESR1) similar to gb|D38124 EREBP-3 from Nicotiana tabacum and contains ...AK119645 002-130-G05 At1g12980.1 AP2 domain-containing transcription factor, putati

  20. Reference: 715 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available 715 http://metadb.riken.jp/db/SciNetS_ria224i/cria224u4ria224u18178585i Ito Shogo et al. 2008 Fe... role by forming a transcriptional feedback core loop together with the morning-e...rcuitry in Arabidopsis thaliana. 2 201-13 18178585 2008 Feb Plant & cell physiology Ito Shogo|Kawamura Hideaki|Mizuno Takeshi|Nakamichi Norihito|Niwa Yusuke|Yamashino Takafumi

  1. Arabidopsis hybrid speciation processes.

    Science.gov (United States)

    Schmickl, Roswitha; Koch, Marcus A

    2011-08-23

    The genus Arabidopsis provides a unique opportunity to study fundamental biological questions in plant sciences using the diploid model species Arabidopsis thaliana and Arabidopsis lyrata. However, only a few studies have focused on introgression and hybrid speciation in Arabidopsis, although polyploidy is a common phenomenon within this genus. More recently, there is growing evidence of significant gene flow between the various Arabidopsis species. So far, we know Arabidopsis suecica and Arabidopsis kamchatica as fully stabilized allopolyploid species. Both species evolved during Pleistocene glaciation and deglaciation cycles in Fennoscandinavia and the amphi-Beringian region, respectively. These hybrid studies were conducted either on a phylogeographic scale or reconstructed experimentally in the laboratory. In our study we focus at a regional and population level. Our research area is located in the foothills of the eastern Austrian Alps, where two Arabidopsis species, Arabidopsis arenosa and A. lyrata ssp. petraea, are sympatrically distributed. Our hypothesis of genetic introgression, migration, and adaptation to the changing environment during the Pleistocene has been confirmed: We observed significant, mainly unidirectional gene flow between the two species, which has given rise to the tetraploid A. lyrata. This cytotype was able to escape from the narrow ecological niche occupied by diploid A. lyrata ssp. petraea on limestone outcrops by migrating northward into siliceous areas, leaving behind a trail of genetic differentiation.

  2. NAC transcription factors in senescence

    DEFF Research Database (Denmark)

    Podzimska-Sroka, Dagmara; O'Shea, Charlotte; Gregersen, Per L.;

    2015-01-01

    Within the last decade, NAC transcription factors have been shown to play essential roles in senescence, which is the focus of this review. Transcriptome analyses associate approximately one third of Arabidopsis NAC genes and many crop NAC genes with senescence, thereby implicating NAC genes...... as important regulators of the senescence process. The consensus DNA binding site of the NAC domain is used to predict NAC target genes, and protein interaction sites can be predicted for the intrinsically disordered transcription regulatory domains of NAC proteins. The molecular characteristics...

  3. Water deficits and heat shock effects on photosynthesis of a transgenic Arabidopsis thaliana constitutively expressing ABP9, a bZIP transcription factor

    DEFF Research Database (Denmark)

    Zhang, Xia; Wollenweber, Bernd; Jiang, Dong

    2008-01-01

    The effects of water deficits (WD), heat shock (HS), and both (HSWD) on photosynthetic carbon- and light-use efficiencies together with leaf ABA content, pigment composition and expressions of stress- and light harvesting-responsive genes were investigated in ABP9 [ABA-responsive-element (ABRE......, altered expression of stress-regulated or light harvesting-responsive genes was observed. Collectively, our results indicate that constitutive expression of ABP9 improves the photosynthetic capacity of plants under stress by adjusting photosynthetic pigment composition, dissipating excess light energy......) binding protein 9] transgenic Arabidopsis (5P2). WD, HS, and HSWD significantly decreased photosynthetic rate (A) and stomatal conductance (gs) in wild-type plants (WT). A and gs of 5P2 transgenic plants were slightly reduced by a single stress and were hardly modified by HSWD. Although A and electron...

  4. Histone Deacetylase Genes in Arabidopsis Development

    Institute of Scientific and Technical Information of China (English)

    Courtney Hollender; Zhongchi Liu

    2008-01-01

    Histone acetylatlon and deacetylation are directly connected with transcriptional activation and silencing in eukaryotas.Gene families for enzymes that accomplish these histone modifications show surprising complexity in domain organization,tissue-specific expression, and function. This review is focused on the family of histone deacetylases (HDACs) that remove the acetyl group from core histone tails, resulting in a "closed" chromatin and transcriptional repression. In Arabidopsis,18 HDAC genes are divided in to three different types - RPD3-1ike, HD-tuin and sirtuin - with two or more members ineach type. The structural feature of each HDAC class, the expression profile of each HDAC gene during development and functional insights of important family members are summarized here. It is clear that HDACs are an important class of global transcriptional regulators that play crucial roles in plant development, defense, and adaptation.

  5. Gravity-regulated gene expression in Arabidopsis thaliana

    Science.gov (United States)

    Sederoff, Heike; Brown, Christopher S.; Heber, Steffen; Kajla, Jyoti D.; Kumar, Sandeep; Lomax, Terri L.; Wheeler, Benjamin; Yalamanchili, Roopa

    Plant growth and development is regulated by changes in environmental signals. Plants sense environmental changes and respond to them by modifying gene expression programs to ad-just cell growth, differentiation, and metabolism. Functional expression of genes comprises many different processes including transcription, translation, post-transcriptional and post-translational modifications, as well as the degradation of RNA and proteins. Recently, it was discovered that small RNAs (sRNA, 18-24 nucleotides long), which are heritable and systemic, are key elements in regulating gene expression in response to biotic and abiotic changes. Sev-eral different classes of sRNAs have been identified that are part of a non-cell autonomous and phloem-mobile network of regulators affecting transcript stability, translational kinetics, and DNA methylation patterns responsible for heritable transcriptional silencing (epigenetics). Our research has focused on gene expression changes in response to gravistimulation of Arabidopsis roots. Using high-throughput technologies including microarrays and 454 sequencing, we iden-tified rapid changes in transcript abundance of genes as well as differential expression of small RNA in Arabidopsis root apices after minutes of reorientation. Some of the differentially regu-lated transcripts are encoded by genes that are important for the bending response. Functional mutants of those genes respond faster to reorientation than the respective wild type plants, indicating that these proteins are repressors of differential cell elongation. We compared the gravity responsive sRNAs to the changes in transcript abundances of their putative targets and identified several potential miRNA: target pairs. Currently, we are using mutant and transgenic Arabidopsis plants to characterize the function of those miRNAs and their putative targets in gravitropic and phototropic responses in Arabidopsis.

  6. The conserved splicing factor SUA controls alternative splicing of the developmental regulator ABI3 in Arabidopsis.

    NARCIS (Netherlands)

    Sugliani, M.; Brambilla, V.; Clerkx, E.J.M.; Koornneef, M.; Soppe, W.J.J.

    2010-01-01

    ABSCISIC ACID INSENSITIVE3 (ABI3) is a major regulator of seed maturation in Arabidopsis thaliana. We detected two ABI3 transcripts, ABI3- and ABI3-ß, which encode full-length and truncated proteins, respectively. Alternative splicing of ABI3 is developmentally regulated, and the ABI3-ß transcript a

  7. SAGE ANALYSIS OF TRANSCRIPTOME RESPONSES IN ARABIDOPSIS ROOTS EXPOSED TO 2,4,6-TRINITROTOLUENE

    Science.gov (United States)

    Serial Analysis of Gene Expression (SAGE) was used to profile transcript levels in Arabidopsis thaliana roots and assess their responses to 2,4,6-trinitrotoluene (TNT) exposure. SAGE libraries representing control and TNT-exposed seedling root transcripts were constructed, and ea...

  8. The arabidopsis cyclic nucleotide interactome

    KAUST Repository

    Donaldson, Lara

    2016-05-11

    Background Cyclic nucleotides have been shown to play important signaling roles in many physiological processes in plants including photosynthesis and defence. Despite this, little is known about cyclic nucleotide-dependent signaling mechanisms in plants since the downstream target proteins remain unknown. This is largely due to the fact that bioinformatics searches fail to identify plant homologs of protein kinases and phosphodiesterases that are the main targets of cyclic nucleotides in animals. Methods An affinity purification technique was used to identify cyclic nucleotide binding proteins in Arabidopsis thaliana. The identified proteins were subjected to a computational analysis that included a sequence, transcriptional co-expression and functional annotation analysis in order to assess their potential role in plant cyclic nucleotide signaling. Results A total of twelve cyclic nucleotide binding proteins were identified experimentally including key enzymes in the Calvin cycle and photorespiration pathway. Importantly, eight of the twelve proteins were shown to contain putative cyclic nucleotide binding domains. Moreover, the identified proteins are post-translationally modified by nitric oxide, transcriptionally co-expressed and annotated to function in hydrogen peroxide signaling and the defence response. The activity of one of these proteins, GLYGOLATE OXIDASE 1, a photorespiratory enzyme that produces hydrogen peroxide in response to Pseudomonas, was shown to be repressed by a combination of cGMP and nitric oxide treatment. Conclusions We propose that the identified proteins function together as points of cross-talk between cyclic nucleotide, nitric oxide and reactive oxygen species signaling during the defence response.

  9. Dynamic antagonism between phytochromes and PIF family basic helix-loop-helix factors induces selective reciprocal responses to light and shade in a rapidly responsive transcriptional network in Arabidopsis.

    Science.gov (United States)

    Leivar, Pablo; Tepperman, James M; Cohn, Megan M; Monte, Elena; Al-Sady, Bassem; Erickson, Erika; Quail, Peter H

    2012-04-01

    Plants respond to shade-modulated light signals via phytochrome (phy)-induced adaptive changes, termed shade avoidance. To examine the roles of Phytochrome-Interacting basic helix-loop-helix Factors, PIF1, 3, 4, and 5, in relaying such signals to the transcriptional network, we compared the shade-responsive transcriptome profiles of wild-type and quadruple pif (pifq) mutants. We identify a subset of genes, enriched in transcription factor-encoding loci, that respond rapidly to shade, in a PIF-dependent manner, and contain promoter G-box motifs, known to bind PIFs. These genes are potential direct targets of phy-PIF signaling that regulate the primary downstream transcriptional circuitry. A second subset of PIF-dependent, early response genes, lacking G-box motifs, are enriched for auxin-responsive loci, and are thus potentially indirect targets of phy-PIF signaling, mediating the rapid cell expansion induced by shade. Comparing deetiolation- and shade-responsive transcriptomes identifies another subset of G-box-containing genes that reciprocally display rapid repression and induction in response to light and shade signals. These data define a core set of transcriptional and hormonal processes that appear to be dynamically poised to react rapidly to light-environment changes via perturbations in the mutually antagonistic actions of the phys and PIFs. Comparing the responsiveness of the pifq and triple pif mutants to light and shade confirms that the PIFs act with overlapping redundancy on seedling morphogenesis and transcriptional regulation but that each PIF contributes differentially to these responses.

  10. MASSUGU2 encodes Aux/IAA19, an auxin-regulated protein that functions together with the transcriptional activator NPH4/ARF7 to regulate differential growth responses of hypocotyl and formation of lateral roots in Arabidopsis thaliana.

    Science.gov (United States)

    Tatematsu, Kiyoshi; Kumagai, Satoshi; Muto, Hideki; Sato, Atsuko; Watahiki, Masaaki K; Harper, Reneé M; Liscum, Emmanuel; Yamamoto, Kotaro T

    2004-02-01

    We have isolated a dominant, auxin-insensitive mutant of Arabidopsis thaliana, massugu2 (msg2), that displays neither hypocotyl gravitropism nor phototropism, fails to maintain an apical hook as an etiolated seedling, and is defective in lateral root formation. Yet other aspects of growth and development of msg2 plants are almost normal. These characteristics of msg2 are similar to those of another auxin-insensitive mutant, non-phototropic hypocotyl4 (nph4), which is a loss-of-function mutant of AUXIN RESPONSE FACTOR7 (ARF7) (Harper et al., 2000). Map-based cloning of the MSG2 locus reveals that all four mutant alleles result in amino acid substitutions in the conserved domain II of an Auxin/Indole-3-Acetic Acid protein, IAA19. Interestingly, auxin inducibility of MSG2/IAA19 gene expression is reduced by 65% in nph4/arf7. Moreover, MSG2/IAA19 protein binds to the C-terminal domain of NPH4/ARF7 in a Saccharomyces cerevisiae (yeast) two-hybrid assay and to the whole latter protein in vitro by pull-down assay. These results suggest that MSG2/IAA19 and NPH4/ARF7 may constitute a negative feedback loop to regulate differential growth responses of hypocotyls and lateral root formation.

  11. Competitive inhibition of transcription factors by small interfering peptides.

    Science.gov (United States)

    Seo, Pil Joon; Hong, Shin-Young; Kim, Sang-Gyu; Park, Chung-Mo

    2011-10-01

    Combinatorial assortment by dynamic dimer formation diversifies gene transcriptional specificities of transcription factors. A similar but biochemically distinct mechanism is competitive inhibition in which small proteins act as negative regulators by competitively forming nonfunctional heterodimers with specific transcription factors. The most extensively studied is the negative regulation of auxin response factors by AUXIN/INDOLE-3-ACETIC ACID repressors. Similarly, Arabidopsis thaliana (Arabidopsis) little zipper and mini finger proteins act as competitive inhibitors of target transcription factors. Competitive inhibitors are also generated by alternative splicing and controlled proteolytic processing. Because they provide a way of attenuating transcription factors we propose to call them small interfering peptides (siPEPs). The siPEP-mediated strategy could be applied to deactivate specific transcription factors in crop plants.

  12. Reference: 705 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available an ample magnitude of epigenetic information for transcription regulation. In fungi, SET2 is the sole methyltransferase re...sponsible for mono-, di-, and trimethylation of H3K36. Here we sho...w that in Arabidopsis thaliana, the degree of H3K36 methylation is regulated by distinct methyltransferases.... The SET2 homologs SDG8 and SDG26 each can methylate oligonucleosomes in vitro, and both proteins are locali...zed in the nucleus. While the previously reported loss-of-function sdg8 mutants h

  13. Reference: 462 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available et al. 2007 Jan. Plant Mol. Biol. 63(2):289-305. NAC proteins are plant-specific transcriptional regulators.... ATAF1 was one of the first identified NAC proteins in Arabidopsis. In present study, we characterized the ATAF1 expre...ssion and biological function in response to water deficit stress. ATAF1 mRNA expre...ssion was strongly induced by dehydration and abscisic acid (ABA) treatment, but inhibited by water tre...atment, suggesting a general role in drought stress responses. Transient expression analysis in onio

  14. Reference: 237 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available member gene family in Arabidopsis (AtFer1-4). To investigate whether iron sequestration in ferritins is a pa...tical time points 0.5 and 24 h post-infection (p.i.). The activation of AtFer1 expression observed at 24 h p...tration of the purified siderophores chrysobactin and desferrioxamine strongly increased AtFer1 transcript a...ia et al. 2005 Jul. Plant J. 43(2):262-72. Ferritins are multimeric iron storage proteins encoded by a four-...rt of an iron-withholding defense system induced in response to bacterial invasio

  15. Transcription co-activator Arabidopsis ANGUSTIFOLIA3 (AN3) regulates water-use efficiency and drought tolerance by modulating stomatal density and improving root architecture by the transrepression of YODA (YDA).

    Science.gov (United States)

    Meng, Lai-Sheng; Yao, Shun-Qiao

    2015-09-01

    One goal of modern agriculture is the improvement of plant drought tolerance and water-use efficiency (WUE). Although stomatal density has been linked to WUE, the causal molecular mechanisms and engineered alternations of this relationship are not yet fully understood. Moreover, YODA (YDA), which is a MAPKK kinase gene, negatively regulates stomatal development. BR-INSENSITIVE 2 interacts with phosphorylates and inhibits YDA. However, whether YDA is modulated in the transcriptional level is still unclear. Plants lacking ANGUSTIFOLIA3 (AN3) activity have high drought stress tolerance because of low stomatal densities and improved root architecture. Such plants also exhibit enhanced WUE through declining transpiration without a demonstrable reduction in biomass accumulation. AN3 negatively regulated YDA expression at the transcriptional level by target-gene analysis. Chromatin immunoprecipitation analysis indicated that AN3 was associated with a region of the YDA promoter in vivo. YDA mutation significantly decreased the stomatal density and root length of an3 mutant, thus proving the participation of YDA in an3 drought tolerance and WUE enhancement. These components form an AN3-YDA complex, which allows the integration of water deficit stress signalling into the production or spacing of stomata and cell proliferation, thus leading to drought tolerance and enhanced WUE.

  16. Reference: 517 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available d isolated aleurone layers of Arabidopsis (Arabidopsis thaliana) were used in experiments designed to iden...tify components of the Arabidopsis seed that contribute to seed dormancy and to lea

  17. Prediction of anther-expressed gene resulation in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    HUANG JiFeng; YANG JingJin; WANG Guan; YU QingBo; YANG ZhongNan

    2008-01-01

    Anther development in Arabidopsis, a popular model plant for plant biology and genetics, is controlled by a complex gene network. Despite the extensive use of this genus for genetic research, little is known about its regulatory network. In this paper, the direct transcriptional regulatory relationships between genes expressed in Arabidopsis anther development were predicted with an integrated bioinformatic method that combines mining of microarray data with promoter analysis. A total of 7710 transcription factor-gene pairs were obtained. The 80 direct regulatory relationships demonstrating the highest con-fidence were screened from the initial 7710 pairs; three of the 80 were validated by previous experi-ments. The results indicate that our predicted results were reliable. The regulatory relationships re-vealed by this research and described in this paper may facilitate further investigation of the molecular mechanisms of anther development. The bioinformatic method used in this work can also be applied to the prediction of gene regulatory relationships in other organisms.

  18. 过表达转录因子 AhAREB1对拟南芥生长素分布的影响%Auxin Distribution in Arabidopsis Plants Over-Expressing AhAREB1 Encoding a Transcription Factor

    Institute of Scientific and Technical Information of China (English)

    林莹莹; 李晓云; 刘帅; 钟钰婷; 李玲

    2015-01-01

    本课题组前期研究表明,过表达AhAREB1(花生AREB转录因子基因)植株矮小,叶片卷曲,抗旱能力增强,体内IAA含量升高,推测AhAREB1可能影响植株体内IAA分布。该文采用携带3个重复IAA化学诱导启动子元件的pDR5:GUS植株与AhAREB1过表达拟南芥植株的杂交纯合后代,通过GUS组织化学染色方法,探讨AhAREB1转录因子对植株体内IAA分布的影响。结果表明,过表达AhAREB1植株体内IAA增加,主要分布在幼苗的根尖和成苗的叶片边缘;在过表达植株IAA响应基因IAA29和IAA运输蛋白基因LAX3表达均显著下调,而IAA响应蛋白基因ARF2和ARF9显著上调。过表达AhAREB1植株体内IAA分布不均衡是引起表型变化的原因之一。%Our previous study showed that Arabidopsis plants over-expressing AhAREB1 ( a peanut AREB transcrip-tion factor) displayed growth retardation, curly leaves, enhanced drought tolerance and increased IAA content.It is implied that auxin distribution may be affected by the expression of AhAREB1.In the present study, the homozy-gous transgenic Arabidopsis, generated by hybridizing the pDR5::GUS ( harboring GUS gene driven by a promoter with three repeat IAA-induced elements) plants with AhAREB1 over-expressing plants, was used to further investi-gate the effect of the expression of AhAREB1 transcription factor on auxin distribution through GUS histochemical staining .The results showed that the IAA content was increased in AhAREB1 over-expressing plants when compared with that in the controlled plants.The IAA mainly accumulated in the root tip of transgenic seedlings, instead on the edge of the leaves in mature plants.The expressions of IAA-responsive genes IAA29 and IAA-transport gene LAX3 in AhAREB1 over-expressing plants were significantly down-regulated, whereas The expressions of other two IAA-responsive genes ARF2 and ARF9 were significantly up-regulated.Take together, the unbalanced IAA distri

  19. Arabidopsis ferritin 1 (AtFer1) gene regulation by the phosphate starvation response 1 (AtPHR1) transcription factor reveals a direct molecular link between iron and phosphate homeostasis.

    Science.gov (United States)

    Bournier, Marc; Tissot, Nicolas; Mari, Stéphane; Boucherez, Jossia; Lacombe, Eric; Briat, Jean-François; Gaymard, Frédéric

    2013-08-01

    A yeast one-hybrid screening allowed the selection of PHR1 as a factor that interacted with the AtFer1 ferritin gene promoter. In mobility shift assays, PHR1 and its close homologue PHL1 (PHR1-like 1) interact with Element 2 of the AtFer1 promoter, containing a P1BS (PHR1 binding site). In a loss of function mutant for genes encoding PHR1 and PHL1 (phr1 phl1 mutant), the response of AtFer1 to phosphate starvation was completely lost, showing that the two transcription factors regulate AtFer1 expression upon phosphate starvation. This regulation does not involve the IDRS (iron-dependent regulatory sequence) present in the AtFer1 promoter and involved in the iron-dependent regulation. The phosphate starvation response of AtFer1 is not linked to the iron status of plants and is specifically initiated by phosphate deficiency. Histochemical localization of iron, visualized by Perls DAB staining, was strongly altered in a phr1 phl1 mutant, revealing that both PHR1 and PHL1 are major factors involved in the regulation of iron homeostasis.

  20. MTHFD1 controls DNA methylation in Arabidopsis

    Science.gov (United States)

    Groth, Martin; Moissiard, Guillaume; Wirtz, Markus; Wang, Haifeng; Garcia-Salinas, Carolina; Ramos-Parra, Perla A.; Bischof, Sylvain; Feng, Suhua; Cokus, Shawn J.; John, Amala; Smith, Danielle C.; Zhai, Jixian; Hale, Christopher J.; Long, Jeff A.; Hell, Ruediger; Díaz de la Garza, Rocío I.; Jacobsen, Steven E.

    2016-01-01

    DNA methylation is an epigenetic mechanism that has important functions in transcriptional silencing and is associated with repressive histone methylation (H3K9me). To further investigate silencing mechanisms, we screened a mutagenized Arabidopsis thaliana population for expression of SDCpro-GFP, redundantly controlled by DNA methyltransferases DRM2 and CMT3. Here, we identify the hypomorphic mutant mthfd1-1, carrying a mutation (R175Q) in the cytoplasmic bifunctional methylenetetrahydrofolate dehydrogenase/methenyltetrahydrofolate cyclohydrolase (MTHFD1). Decreased levels of oxidized tetrahydrofolates in mthfd1-1 and lethality of loss-of-function demonstrate the essential enzymatic role of MTHFD1 in Arabidopsis. Accumulation of homocysteine and S-adenosylhomocysteine, genome-wide DNA hypomethylation, loss of H3K9me and transposon derepression indicate that S-adenosylmethionine-dependent transmethylation is inhibited in mthfd1-1. Comparative analysis of DNA methylation revealed that the CMT3 and CMT2 pathways involving positive feedback with H3K9me are mostly affected. Our work highlights the sensitivity of epigenetic networks to one-carbon metabolism due to their common S-adenosylmethionine-dependent transmethylation and has implications for human MTHFD1-associated diseases. PMID:27291711

  1. Reference: 400 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available aintaining developmental regulators in a transcriptionally repressed state. We identified a novel flowering ...gene that is under PcG control in Arabidopsis--the MADS-box gene AGL19. AGL19 expre...ssion is maintained at very low levels by the PcG proteins MSI1, CLF, and EMF2, and AGL19 is partly respon...on of Lys 27 on histone H3 (H3K27me3) but not in H3K9me2. Repressive H3K27me3 marks were reduced by decre...ased CLF or MSI1 levels and by prolonged cold, suggesting that the PcG proteins MSI1 and CLF repre

  2. Hormonal Regulation of Leaf Morphogenesis in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Lin-Chuan Li; Ding-Ming Kang; Zhang-Liang Chen; Li-Jia Qu

    2007-01-01

    Leaf morphogenesis is strictly controlled not only by intrinsic genetic factors, such as transcriptional factors, but also by environmental cues, such as light, water and pathogens. Nevertheless, the molecular mechanism of how leaf rnorphogenesis is regulated by genetic programs and environmental cues is far from clear. Numerous series of events demonstrate that plant hormones, mostly small and simple molecules,play crucial roles in plant growth and development, and in responses of plants to environmental cues such as light. With more and more genetics and molecular evidence obtained from the model plant Arabidopsis,several fundamental aspects of leaf rnorphogenesis including the initiation of leaf primordia, the determination of leaf axes, the regulation of cell division and expansion in leaves have been gradually unveiled.Among these phytohormones, auxin is found to be essential in the regulation of leaf morphogenesis.

  3. Arabidopsis Clade I TGA Factors Regulate Apoplastic Defences against the Bacterial Pathogen Pseudomonas syringae through Endoplasmic Reticulum-Based Processes

    OpenAIRE

    Lipu Wang; Pierre R Fobert

    2013-01-01

    During the plant immune response, large-scale transcriptional reprogramming is modulated by numerous transcription (co) factors. The Arabidopsis basic leucine zipper transcription factors TGA1 and TGA4, which comprise the clade I TGA factors, have been shown to positively contribute to disease resistance against virulent strains of the bacterial pathogen Pseudomonas syringae . Despite physically interacting with the key immune regulator, NON-EXPRESSOR OF PATHOGENESIS-RELATED GENES 1 (NPR1), f...

  4. 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....

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

    DEFF Research Database (Denmark)

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

    2013-01-01

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

  6. The Functions of RNA-Dependent RNA Polymerases in Arabidopsis

    Science.gov (United States)

    Willmann, Matthew R.; Endres, Matthew W.; Cook, Rebecca T.; Gregory, Brian D.

    2011-01-01

    One recently identified mechanism that regulates mRNA abundance is RNA silencing, and pioneering work in Arabidopsis thaliana and other genetic model organisms helped define this process. RNA silencing pathways are triggered by either self-complementary fold-back structures or the production of double-stranded RNA (dsRNA) that gives rise to small RNAs (smRNAs) known as microRNAs (miRNAs) or small-interfering RNAs (siRNAs). These smRNAs direct sequence-specific regulation of various gene transcripts, repetitive sequences, viruses, and mobile elements via RNA cleavage, translational inhibition, or transcriptional silencing through DNA methylation and heterochromatin formation. Early genetic screens in Arabidopsis were instrumental in uncovering numerous proteins required for these important regulatory pathways. Among the factors identified by these studies were RNA-dependent RNA polymerases (RDRs), which are proteins that synthesize siRNA-producing dsRNA molecules using a single-stranded RNA (ssRNA) molecule as a template. Recently, a growing body of evidence has implicated RDR-dependent RNA silencing in many different aspects of plant biology ranging from reproductive development to pathogen resistance. Here, we focus on the specific functions of the six Arabidopsis RDRs in RNA silencing, their ssRNA substrates and resulting RDR-dependent smRNAs, and the numerous biological functions of these proteins in plant development and stress responses. PMID:22303271

  7. Comparative transcriptomics of early meiosis in Arabidopsis and maize.

    Science.gov (United States)

    Dukowic-Schulze, Stefanie; Harris, Anthony; Li, Junhua; Sundararajan, Anitha; Mudge, Joann; Retzel, Ernest F; Pawlowski, Wojciech P; Chen, Changbin

    2014-03-20

    Though sexually reproductive plants share the same principle and most processes in meiosis, there are distinct features detectable. To address the similarities and differences of early meiosis transcriptomes from the dicot model system Arabidopsis and monocot model system maize, we performed comparative analyses of RNA-seq data of isolated meiocytes, anthers and seedlings from both species separately and via orthologous genes. Overall gene expression showed similarities, such as an increased number of reads mapping to unannotated features, and differences, such as the amount of differentially expressed genes. We detected major similarities and differences in functional annotations of genes up-regulated in meiocytes, which point to conserved features as well as unique features. Transcriptional regulation seems to be quite similar in Arabidopsis and maize, and we could reveal known and novel transcription factors and cis-regulatory elements acting in early meiosis. Taken together, meiosis between Arabidopsis and maize is conserved in many ways, but displays key distinctions that lie in the patterns of gene expression.

  8. The Impact of the Absence of Aliphatic Glucosinolates on Insect Herbivory in Arabidopsis

    NARCIS (Netherlands)

    Beekwilder, J.; van Leeuwen, W.; Van Dam, N.M.; Bertossi, M.; Grandi, V.; Mizzi, L.; Soloviev, M.; Szabados, L.; Molthoff, J.W.; Schipper, B.; Verbocht, H.; de Vos, R.C.H.; Morandini, P.; Aarts, M.G.M.; Bovy, A.

    2008-01-01

    Aliphatic glucosinolates are compounds which occur in high concentrations in Arabidopsis thaliana and other Brassicaceae species. They are important for the resistance of the plant to pest insects. Previously, the biosynthesis of these compounds was shown to be regulated by transcription factors MYB

  9. Interacting protein partners of Arabidopsis RNA binding protein AtRBP45b

    Science.gov (United States)

    RNA binding proteins (RBPs) are important players in post-transcriptional gene regulation and shown to play an important role in normal development and in response to environmental perturbations. Arabidopsis RBP, AtRBP45b with triple RNA recognition motifs (RRMs) have are closely related to the yeas...

  10. PRR3 Is a Vascular Regulator of TOC1 Stability in the Arabidopsis Circadian Clock

    Science.gov (United States)

    The pseudoresponse regulators (PRRs) participate in the progression of the circadian clock in Arabidopsis thaliana. The founding member of the family, TIMING OF CAB EXPRESSION1 (TOC1), is an essential component of the transcriptional network that constitutes the core mechanism of the circadian oscil...

  11. Sucrose regulated translational control of bZip genes in Arabidopsis thaliana

    NARCIS (Netherlands)

    Rahmani, F.

    2007-01-01

    Sucrose can translationally regulate the expression of bZIP11 and four other S-class bZip transcription factors in Arabidopsis thaliana. Sequence encoding 28 amino acids (SC-peptide) in the leader of the bZIP11 is sufficient to mediate sucrose induced translational control. A model proposes that suc

  12. Functionally Similar WRKY Proteins Regulate Vacuolar Acidification in Petunia and Hair Development in Arabidopsis

    NARCIS (Netherlands)

    Verweij, W.; Spelt, C.E.; Bliek, M.; de Vries, M.; Wit, N.; Faraco, M.; Koes, R.; Quattrocchio, F.

    2016-01-01

    The WD40 proteins ANTHOCYANIN11 (AN11) from petunia (Petunia hybrida) and TRANSPARENT TESTA GLABRA1 (TTG1) fromArabidopsis thalianaand associated basic helix-loop-helix (bHLH) and MYB transcription factors activate a variety of differentiation processes. In petunia petals, AN11 and the bHLH protein

  13. An INDEHISCENT-Controlled Auxin Response Specifies the Separation Layer in Early Arabidopsis Fruit

    NARCIS (Netherlands)

    van Gelderen, Kasper; van Rongen, Martin; Liu, An'an; Otten, Anne; Offringa, Remko

    2016-01-01

    Seed dispersal is an important moment in the life cycle of a plant species. In Arabidopsis thaliana, it is dependent on transcription factor INDEHISCENT (IND)-mediated specification of a separation layer in the dehiscence zone found in the margin between the valves (carpel walls) and the central rep

  14. Modelling the molecular interactions in the flower developmental network of Arabidopsis thaliana

    NARCIS (Netherlands)

    Kaufmann, K.; Nagasaki, M.; Jáuregui., R.

    2010-01-01

    We present a dynamical model of the gene network controlling flower development in Arabidopsis thaliana. The network is centered at the regulation of the floral organ identity genes (AP1, AP2, AP3, PI and AG) and ends with the transcription factor complexes responsible for differentiation of floral

  15. Navigating the transcriptional roadmap regulating plant secondary cell wall deposition

    Directory of Open Access Journals (Sweden)

    Steven Grant Hussey

    2013-08-01

    Full Text Available The current status of lignocellulosic biomass as an invaluable resource in industry, agriculture and health has spurred increased interest in understanding the transcriptional regulation of secondary cell wall (SCW biosynthesis. The last decade of research has revealed an extensive network of NAC, MYB and other families of transcription factors regulating Arabidopsis SCW biosynthesis, and numerous studies have explored SCW-related transcription factors in other dicots and monocots. Whilst the general structure of the Arabidopsis network has been a topic of several reviews, they have not comprehensively represented the detailed protein-DNA and protein-protein interactions described in the literature, and an understanding of network dynamics and functionality has not yet been achieved for SCW formation. Furthermore the methodologies employed in studies of SCW transcriptional regulation have not received much attention, especially in the case of non-model organisms. In this review, we have reconstructed the most exhaustive literature-based network representations to date of SCW transcriptional regulation in Arabidopsis. We include a manipulable Cytoscape representation of the Arabidopsis SCW transcriptional network to aid in future studies, along with a list of supporting literature for each documented interaction. Amongst other topics, we discuss the various components of the network, its evolutionary conservation in plants, putative modules and dynamic mechanisms that may influence network function, and the approaches that have been employed in network inference. Future research should aim to better understand network function and its response to dynamic perturbations, whilst the development and application of genome-wide approaches such as ChIP-seq and systems genetics are in progress for the study of SCW transcriptional regulation in non-model organisms.

  16. Elucidating the germination transcriptional program using small molecules.

    Science.gov (United States)

    Bassel, George W; Fung, Pauline; Chow, Tsz-fung Freeman; Foong, Justin A; Provart, Nicholas J; Cutler, Sean R

    2008-05-01

    The transition from seed to seedling is mediated by germination, a complex process that starts with imbibition and completes with radicle emergence. To gain insight into the transcriptional program mediating germination, previous studies have compared the transcript profiles of dry, dormant, and germinating after-ripened Arabidopsis (Arabidopsis thaliana) seeds. While informative, these approaches did not distinguish the transcriptional responses due to imbibition, shifts in metabolism, or breaking of dormancy from those triggered by the initiation of germination. In this study, three mechanistically distinct small molecules that inhibit Arabidopsis seed germination (methotrexate, 2, 4-dinitrophenol, and cycloheximide) were identified using a small-molecule screen and used to probe the germination transcriptome. Germination-responsive transcripts were defined as those with significantly altered transcript abundance across all inhibitory treatments with respect to control germinating seeds, using data from ATH1 microarrays. This analysis identified numerous germination regulators as germination responsive, including the DELLA proteins GAI, RGA, and RGL3, the abscisic acid-insensitive proteins ABI4, ABI5, ABI8, and FRY1, and the gibberellin receptor GID1A. To help visualize these and other publicly available seed microarray data, we designed a seed mRNA expression browser using the electronic Fluorescent Pictograph platform. An overall decrease in gene expression and a 5-fold greater number of transcripts identified as statistically down-regulated in drug-inhibited seeds point to a role for mRNA degradation or turnover during seed germination. The genes identified in our study as responsive to germination define potential uncharacterized regulators of this process and provide a refined transcriptional signature for germinating Arabidopsis seeds.

  17. 3' Rapid Amplification of cDNA Ends (3' RACE) Using Arabidopsis Samples.

    Science.gov (United States)

    Rodríguez-Cazorla, Encarnación; Andújar, Alfonso; Ripoll, Juan José; Bailey, Lindsay J; Martínez-Laborda, Antonio; Yanofsky, Martin F; Vera, Antonio

    2015-10-05

    Production of functional eukaryotic RNA is a very elaborate process that involves a complex interplay between transcription and various RNA processing activities, including splicing, 5' capping, and 3' cleavage and polyadenylation (Bentley, 2014). Accurate mapping of RNA ends provides a valuable tool to assess transcriptional and post-transcriptional events giving rise to different gene transcripts. The abundance of such transcripts most likely depends on exogenous and developmental cues, or mutations. In the reference plant Arabidopsis, perturbation of the HUA-PEP post-transcriptional regulatory factors (Rodríguez-Cazorla et al., 2015) leads to the accumulation of aberrant transcripts of the key floral homeotic gene AGAMOUS (AG) (Yanofsky et al., 1990) that retain intronic sequence. It was determined by 3' RACE reactions that such erroneous transcripts correspond to premature processing and polyadenylation events taking place at the AG intron region. Here we describe a protocol that is suitable for analysis of relatively abundant transcripts and also for detecting aberrant RNA species that are likely prone to rapid turnover. Likewise, the method, here adapted to Arabidopsis reproductive tissues, can be applied to characterize RNA species from other organs (leaf, root) and/or other plant species. We provide a detailed protocol of our 3' RACE procedure comprising four major parts: Total RNA extraction, RNA amount determination and quality control, the RACE procedure itself, and isolation of the resulting RACE products for cloning and sequencing.

  18. Functionality of soybean CBF/DREB1 transcription factors.

    Science.gov (United States)

    Yamasaki, Yuji; Randall, Stephen K

    2016-05-01

    Soybean (Glycine max) is considered to be cold intolerant and is not able to significantly acclimate to cold/freezing stress. In most cold tolerant plants, the C-repeat/DRE Binding Factors (CBF/DREBs) are critical contributors to successful cold-responses; rapidly increasing following cold treatment and regulating the induction of many cold responsive genes. In soybean vegetative tissue, we found strong, transient accumulation of CBF transcripts in response to cold stress; however, the soybean transcripts of typical cold responsive genes (homologues to Arabidopsis genes such as dehydrins, ADH1, RAP2.1, and LEA14) were not significantly altered. Soybean CBFs were found to be functional, as when expressed constitutively in Arabidopsis they increased the levels of AtCOR47 and AtRD29a transcripts and increased freezing tolerance as measured by a decrease in leaf freezing damage and ion leakage. Furthermore the constitutive expression of GmDREB1A;2 and GmDREB1B;1 in Arabidopsis led to stronger up-regulation of downstream genes and more freezing tolerance than GmDREB1A;1, the gene whose transcript is the major contributor to total CBF/DREB1 transcripts in soybean. The inability for the soybean CBFs to significantly up regulate the soybean genes that contribute to cold tolerance is consistent with poor acclimation capability and the cold intolerance of soybean.

  19. Molecular cloning of cryptochrome 1 from apple and its functional characterization in Arabidopsis.

    Science.gov (United States)

    Li, Yuan-Yuan; Mao, Ke; Zhao, Cheng; Zhang, Rui-Fen; Zhao, Xian-Yan; Zhang, Hua-Lei; Shu, Huai-Rui; Zhao, Yu-Jin

    2013-06-01

    Cryptochromes are blue-light photoreceptors involved in regulating many aspects of plant growth and development. Investigations of cryptochromes in plants have largely focused on Arabidopsis (Arabidopsis thaliana), tomato (Solanum lycopersicum), rice (Oryza sativa) and pea (Pisum sativum). Here, we isolated the cryptochrome 1 gene from apple (Malus domestica) (MdCRY1) and analyzed its function in transgenic Arabidopsis. The predicted MdCRY1 protein was most closely homologous to strawberry CRY1. In terms of transcript levels, MdCRY1 expression was up-regulated by light. The function of MdCRY1 was analyzed through heterologous expression in Arabidopsis. Overexpression of MdCRY1 in Arabidopsis is able to rescue the cry1 mutant phenotype, inhibit hypocotyl elongation, promote root growth, and enhance anthocyanin accumulation in wild-type seedlings under blue light. These data provide functional evidence for a role of MdCRY1 in controlling photomorphogenesis under blue light and indicate that CRY1 function is conserved between Arabidopsis and apple. Furthermore, we found that MdCRY1 interacts with AtCOP1 in both yeast and onion cells. This interaction may represent an important regulatory mechanism in blue-light signaling pathway in apple.

  20. Systemic low temperature signaling in Arabidopsis.

    Science.gov (United States)

    Gorsuch, Peter A; Sargeant, Alexander W; Penfield, Steven D; Quick, W Paul; Atkin, Owen K

    2010-09-01

    When leaves are exposed to low temperature, sugars accumulate and transcription factors in the C-repeat binding factor (CBF) family are expressed, which, together with CBF-independent pathways, are known to contribute to the cold acclimation process and an increase in freezing tolerance. What is not known, however, is whether expression of these cold-regulated genes can be induced systemically in response to a localized cold treatment. To address this, pre-existing, mature leaves of warm-grown Arabidopsis thaliana were exposed to a localized cold treatment (near 10 °C) whilst conjoined newly developing leaves continued only to experience warmer temperatures. In initial experiments on wild-type A. thaliana (Col-0) using real-time reverse transcription--PCR (RT-PCR) we observed that some genes--including CBF genes, certain downstream cold-responsive (COR) targets and CBF-independent transcription factors--respond to a direct 9 °C treatment of whole plants. In subsequent experiments, we found that the treatment of expanded leaves with temperatures near 10 °C can induce cold-associated genes in conjoined warm-maintained tissues. CBF1 showed a particularly strong systemic response, although CBF-independent transcription factors also responded. Moreover, the localized cold treatment of A. thaliana (C24) plants with a luciferase reporter fused to the promoter region of KIN2 indicated that in warm-maintained leaves, KIN2 might respond to a systemic signal from remote, directly cold-treated leaves. Collectively, our study provides strong evidence that the processes involved in cold acclimation are partially mediated by a signal that acts systemically. This has the potential to act as an early-warning system to enable developing leaves to cope better with the cold environment in which they are growing.

  1. 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

  2. Reference: 398 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available plays attenuated chloroplast movements under intermediate and high light intensitie...hese movements. In this work, we describe plastid movement impaired 2 (pmi2), a mutant in Arabidopsis (Arabidopsis thaliana) that dis

  3. Reference: 173 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available mical approaches to elucidate the action mechanisms of sirtinol in Arabidopsis. A...tic and chemical analyses of the action mechanisms of sirtinol in Arabidopsis. 8 3129-34 15710899 2005 Feb P

  4. Reference: 718 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available displayed a moderate but significant decrease in germination in the presence of D...NA damage. This report links Ubc13-Uev with functions in DNA damage response in Arabidopsis. Arabidopsis UEV

  5. Arabidopsis CDS blastp result: AK068856 [KOME

    Lifescience Database Archive (English)

    Full Text Available eme oxygenase (HY1) [Arabidopsis thaliana] GI:4877362, heme oxygenase 1 [Arabidopsis thaliana] GI:4530591 GB:AF132475; annotation upd...ated per Seth J. Davis at University of Wisconsin-Madison 3e-90 ...

  6. Arabidopsis CDS blastp result: AK104955 [KOME

    Lifescience Database Archive (English)

    Full Text Available B:AF132475; annotation updated per Seth J. Davis at University of Wisconsin-Madison 3e-90 ... ...heme oxygenase (HY1) [Arabidopsis thaliana] GI:4877362, heme oxygenase 1 [Arabidopsis thaliana] GI:4530591 G

  7. Reference: 110 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available on process. Our study shows that an Arabidopsis SNM protein, although structurally closer to the SNM1/PSO2 members, shares some prope...rties with ARTEMIS but also has novel characteristics. Arabidopsis plants defective

  8. Meta-analysis of Arabidopsis KANADI1 direct target genes identifies basic growth-promoting module acting upstream of hormonal signaling pathways

    DEFF Research Database (Denmark)

    Xie, Yakun; Straub, Daniel; Eguen, Teinai Ebimienere;

    2015-01-01

    An intricate network of antagonistically acting transcription factors mediates formation of a flat leaf lamina of Arabidopsis thaliana plants. In this context, members of the class III homeodomain leucine zipper (HD-ZIPIII) transcription factor family specify the adaxial domain (future upper side...

  9. Cell fate in the Arabidopsis root epidermis is determined by competition between WEREWOLF and CAPRICE.

    Science.gov (United States)

    Song, Sang-Kee; Ryu, Kook Hui; Kang, Yeon Hee; Song, Jae Hyo; Cho, Young-Hee; Yoo, Sang-Dong; Schiefelbein, John; Lee, Myeong Min

    2011-11-01

    The root hair and nonhair cells in the Arabidopsis (Arabidopsis thaliana) root epidermis are specified by a suite of transcriptional regulators. Two of these are WEREWOLF (WER) and CAPRICE (CPC), which encode MYB transcription factors that are required for promoting the nonhair cell fate and the hair cell fate, respectively. However, the precise function and relationship between these transcriptional regulators have not been fully defined experimentally. Here, we examine these issues by misexpressing the WER gene using the GAL4-upstream activation sequence transactivation system. We find that WER overexpression in the Arabidopsis root tip is sufficient to cause epidermal cells to adopt the nonhair cell fate through direct induction of GLABRA2 (GL2) gene expression. We also show that GLABRA3 (GL3) and ENHANCER OF GLABRA3 (EGL3), two closely related bHLH proteins, are required for the action of the overexpressed WER and that WER interacts with these bHLHs in plant cells. Furthermore, we find that CPC suppresses the WER overexpression phenotype quantitatively. These results show that WER acts together with GL3/EGL3 to induce GL2 expression and that WER and CPC compete with one another to define cell fates in the Arabidopsis root epidermis.

  10. TAF13 interacts with PRC2 members and is essential for Arabidopsis seed development.

    Science.gov (United States)

    Lindner, Matias; Simonini, Sara; Kooiker, Maarten; Gagliardini, Valeria; Somssich, Marc; Hohenstatt, Mareike; Simon, Rüdiger; Grossniklaus, Ueli; Kater, Martin M

    2013-07-01

    TBP-Associated Factors (TAFs) are components of complexes like TFIID, TFTC, SAGA/STAGA and SMAT that are important for the activation of transcription, either by establishing the basic transcription machinery or by facilitating histone acetylation. However, in Drosophila embryos several TAFs were shown to be associated with the Polycomb Repressive Complex 1 (PRC1), even though the role of this interaction remains unclear. Here we show that in Arabidopsis TAF13 interacts with MEDEA and SWINGER, both members of a plant variant of Polycomb Repressive Complex 2 (PRC2). PRC2 variants play important roles during the plant life cycle, including seed development. The taf13 mutation causes seed defects, showing embryo arrest at the 8-16 cell stage and over-proliferation of the endosperm in the chalazal region, which is typical for Arabidopsis PRC2 mutants. Our data suggest that TAF13 functions together with PRC2 in transcriptional regulation during seed development.

  11. G2 Checkpoint Responses in Arabidopsis

    Energy Technology Data Exchange (ETDEWEB)

    Britt, Anne

    2013-03-18

    This project focused on the mechanism and biological significance of the G2 arrest response to replication stress in plants. We employed both forward and reverse genetic approaches to identify genes required for this response. A total of 3 different postdocs, 5 undergraduates, and 2 graduate students participated in the project. We identified several genes required for damage response in plants, including homologs of genes previously identified in animals (ATM and ATR), novel, a plant-specific genes (SOG1) and a gene known in animals but previously thought to be missing from the Arabidopsis genome (ATRIP). We characterized the transcriptome of gamma-irradiated plants, and found that plants, unlike animals, express a robust transcriptional response to damage, involving genes that regulate the cell cycle and DNA metabolism. This response requires both ATM and the transcription factor SOG1. We found that both ATM and ATR play a role in meiosis in plants. We also found that plants have a cell-type-specific programmed cell death response to ionizing radiation and UV light, and that this response requires ATR, ATM, and SOG1. These results were published in a series of 5 papers.

  12. Developmentally distinct MYB genes encode functionally equivalent proteins in Arabidopsis.

    Science.gov (United States)

    Lee, M M; Schiefelbein, J

    2001-05-01

    The duplication and divergence of developmental control genes is thought to have driven morphological diversification during the evolution of multicellular organisms. To examine the molecular basis of this process, we analyzed the functional relationship between two paralogous MYB transcription factor genes, WEREWOLF (WER) and GLABROUS1 (GL1), in Arabidopsis. The WER and GL1 genes specify distinct cell types and exhibit non-overlapping expression patterns during Arabidopsis development. Nevertheless, reciprocal complementation experiments with a series of gene fusions showed that WER and GL1 encode functionally equivalent proteins, and their unique roles in plant development are entirely due to differences in their cis-regulatory sequences. Similar experiments with a distantly related MYB gene (MYB2) showed that its product cannot functionally substitute for WER or GL1. Furthermore, an analysis of the WER and GL1 proteins shows that conserved sequences correspond to specific functional domains. These results provide new insights into the evolution of the MYB gene family in Arabidopsis, and, more generally, they demonstrate that novel developmental gene function may arise solely by the modification of cis-regulatory sequences.

  13. Comparative Proteomic Analysis of Arabidopsis Mature Pollen and Germinated Pollen

    Institute of Scientific and Technical Information of China (English)

    Junjie Zou; Lianfen Song; Wenzheng Zhang; Yi Wang; Songlin Ruan; Wei-Hua Wu

    2009-01-01

    Proteomic analysis was applied to generating the map of Arabidopsis mature pollen proteins and analyzing the differentially expressed proteins that are potentially involved in the regulation of Arabidopsis pollen germination. By applying 2-D electrophoresis and silver staining, we resolved 499 and 494 protein spots from protein samples extracted from pollen grains and pollen tubes, respectively. Using the matrix-assisted laser desorption ionization time-of-flight mass spectrometry method, we identified 189 distinct proteins from 213 protein spots expressed in mature pollen or pollen tubes, and 75 new identified proteins that had not been reported before in research into the Arabidopsis pollen proteome. Comparative analysis revealed that 40 protein spots exhibit reproducible significant changes between mature pollen and pollen tubes. And 21 proteins from 17 downregulated and six upregulated protein spots were identified. Functional category analysis indicated that these differentially expressed proteins mainly involved in signaling, cellular structure, transport, defense/stress responses, transcription, metabolism, and energy production. The patterns of changes at protein level suggested the important roles for energy metabolism-related proteins in pollen tube growth, accompanied by the activation of the stress response pathway and modifications to the cell wall.

  14. Arabidopsis thaliana peroxidase N

    DEFF Research Database (Denmark)

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

    2000-01-01

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

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

    NARCIS (Netherlands)

    Urbanus, S.L.

    2010-01-01

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

  16. Chromatin Remodeling in Stem Cell Maintenance in Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    Lin Xu; Wen-Hui Shen

    2009-01-01

    Pluripotent stem cells are able to both self-renew and generate undifferentiated cells for the formation of new tissues and organs.In higher plants,stem cells found in the shoot apical meristem (SAM) and the root apical meristem (RAM) are origins of organogenesis occurring post-embryonically.It is important to understand how the regulation of stem cell fate is coordinated to enable the meristem to constantly generate different types of lateral organs.Much knowledge has accumulated on specific transcription factors controlling SAM and RAM activity.Here,we review recent evidences for a role of chromatin remodeling in the maintenance of stable expression states of transcription factor genes and the control of stem cell activity in Arabidopsis.

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

    Science.gov (United States)

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

    2016-07-14

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

  18. Environmental History Modulates Arabidopsis Pattern-Triggered Immunity in a HISTONE ACETYLTRANSFERASE1-Dependent Manner.

    Science.gov (United States)

    Singh, Prashant; Yekondi, Shweta; Chen, Po-Wen; Tsai, Chia-Hong; Yu, Chun-Wei; Wu, Keqiang; Zimmerli, Laurent

    2014-06-01

    In nature, plants are exposed to a fluctuating environment, and individuals exposed to contrasting environmental factors develop different environmental histories. Whether different environmental histories alter plant responses to a current stress remains elusive. Here, we show that environmental history modulates the plant response to microbial pathogens. Arabidopsis thaliana plants exposed to repetitive heat, cold, or salt stress were more resistant to virulent bacteria than Arabidopsis grown in a more stable environment. By contrast, long-term exposure to heat, cold, or exposure to high concentrations of NaCl did not provide enhanced protection against bacteria. Enhanced resistance occurred with priming of Arabidopsis pattern-triggered immunity (PTI)-responsive genes and the potentiation of PTI-mediated callose deposition. In repetitively stress-challenged Arabidopsis, PTI-responsive genes showed enrichment for epigenetic marks associated with transcriptional activation. Upon bacterial infection, enrichment of RNA polymerase II at primed PTI marker genes was observed in environmentally challenged Arabidopsis. Finally, repetitively stress-challenged histone acetyltransferase1-1 (hac1-1) mutants failed to demonstrate enhanced resistance to bacteria, priming of PTI, and increased open chromatin states. These findings reveal that environmental history shapes the plant response to bacteria through the development of a HAC1-dependent epigenetic mark characteristic of a primed PTI response, demonstrating a mechanistic link between the primed state in plants and epigenetics.

  19. A near-null magnetic field affects cryptochrome-related hypocotyl growth and flowering in Arabidopsis

    Science.gov (United States)

    Xu, Chunxiao; Yin, Xiao; Lv, Yan; Wu, Changzhe; Zhang, Yuxia; Song, Tao

    2012-03-01

    The blue light receptor, cryptochrome, has been suggested to act as a magnetoreceptor based on the proposition that photochemical reactions are involved in sensing the geomagnetic field. But the effects of the geomagnetic field on cryptochrome remain unclear. Although the functions of cryptochrome have been well demonstrated for Arabidopsis, the effect of the geomagnetic field on the growth of Arabidopsis and its mechanism of action are poorly understood. We eliminated the local geomagnetic field to grow Arabidopsis in a near-null magnetic field and found that the inhibition of Arabidopsis hypocotyl growth by white light was weakened, and flowering time was delayed. The expressions of three cryptochrome-signaling-related genes, PHYB, CO and FT also changed; the transcript level of PHYB was elevated ca. 40%, and that of CO and FT was reduced ca. 40% and 50%, respectively. These data suggest that the effects of a near-null magnetic field on Arabidopsis are cryptochrome-related, which may be revealed by a modification of the active state of cryptochrome and the subsequent signaling cascade.

  20. Physiological and transcriptomic aspects of urea uptake and assimilation in Arabidopsis plants.

    Science.gov (United States)

    Mérigout, Patricia; Lelandais, Maud; Bitton, Frédérique; Renou, Jean-Pierre; Briand, Xavier; Meyer, Christian; Daniel-Vedele, Françoise

    2008-07-01

    Urea is the major nitrogen (N) form supplied as fertilizer in agriculture, but it is also an important N metabolite in plants. Urea transport and assimilation were investigated in Arabidopsis (Arabidopsis thaliana). Uptake studies using (15)N-labeled urea demonstrated the capacity of Arabidopsis to absorb urea and that the urea uptake was regulated by the initial N status of the plants. Urea uptake was stimulated by urea but was reduced by the presence of ammonium nitrate in the growth medium. N deficiency in plants did not affect urea uptake. Urea exerted a repressive effect on nitrate influx, whereas urea enhanced ammonium uptake. The use of [(15)N]urea and [(15)N]ammonium tracers allowed us to show that urea and ammonium assimilation pathways were similar. Finally, urea uptake was less efficient than nitrate uptake, and urea grown-plants presented signs of N starvation. We also report the first analysis, to our knowledge, of Arabidopsis gene expression profiling in response to urea. Our transcriptomic approach revealed that nitrate and ammonium transporters were transcriptionally regulated by urea as well as key enzymes of the glutamine synthetase-glutamate synthase pathway. AtDUR3, a high-affinity urea transporter in Arabidopsis, was strongly up-regulated by urea. Moreover, our transcriptomic data suggest that other genes are also involved in urea influx.

  1. UDP-glucosyltransferase71c5, a major glucosyltransferase, mediates abscisic acid homeostasis in Arabidopsis.

    Science.gov (United States)

    Liu, Zhen; Yan, Jin-Ping; Li, De-Kuan; Luo, Qin; Yan, Qiujie; Liu, Zhi-Bin; Ye, Li-Ming; Wang, Jian-Mei; Li, Xu-Feng; Yang, Yi

    2015-04-01

    Abscisic acid (ABA) plays a key role in plant growth and development. The effect of ABA in plants mainly depends on its concentration, which is determined by a balance between biosynthesis and catabolism of ABA. In this study, we characterize a unique UDP-glucosyltransferase (UGT), UGT71C5, which plays an important role in ABA homeostasis by glucosylating ABA to abscisic acid -: glucose ester (GE) in Arabidopsis (Arabidopsis thaliana). Biochemical analyses show that UGT71C5 glucosylates ABA in vitro and in vivo. Mutation of UGT71C5 and down-expression of UGT71C5 in Arabidopsis cause delay in seed germination and enhanced drought tolerance. In contrast, overexpression of UGT71C5 accelerates seed germination and reduces drought tolerance. Determination of the content of ABA and ABA-GE in Arabidopsis revealed that mutation in UGT71C5 and down-expression of UGT71C5 resulted in increased level of ABA and reduced level of ABA-GE, whereas overexpression of UGT71C5 resulted in reduced level of ABA and increased level of ABA-GE. Furthermore, altered levels of ABA in plants lead to changes in transcript abundance of ABA-responsive genes, correlating with the concentration of ABA regulated by UGT71C5 in Arabidopsis. Our work shows that UGT71C5 plays a major role in ABA glucosylation for ABA homeostasis.

  2. The Arabidopsis NIMIN proteins affect NPR1 differentially

    Directory of Open Access Journals (Sweden)

    Meike eHermann

    2013-04-01

    Full Text Available NON-EXPRESSOR OF PATHOGENESIS-RELATED GENES1 (NPR1 is the central regulator of the pathogen defense reaction systemic acquired resistance (SAR. NPR1 acts by sensing the SAR signal molecule salicylic acid (SA to induce expression of PATHOGENESIS-RELATED (PR genes. Mechanistically, NPR1 is the core of a transcription complex interacting with TGA transcription factors and NIM1 INTERACTING (NIMIN proteins. Arabidopsis NIMIN1 has been shown to suppress NPR1 activity in transgenic plants. The Arabidopsis NIMIN family comprises four structurally related, yet distinct members. Here, we show that NIMIN1, NIMIN2 and NIMIN3 are expressed differentially, and that the encoded proteins affect expression of the SAR marker PR-1 differentially. NIMIN3 is expressed constitutively at a low level, but NIMIN2 and NIMIN1 are both responsive to SA. While NIMIN2 is an immediate early SA-induced and NPR1-independent gene, NIMIN1 is activated after NIMIN2, but clearly before PR-1. Notably, NIMIN1, like PR-1, depends on NPR1. In a transient assay system, NIMIN3 suppresses SA-induced PR-1 expression, albeit to a lesser extent than NIMIN1, whereas NIMIN2 does not negatively affect PR-1 gene activation. Furthermore, although binding to the same domain in the C-terminus, NIMIN1 and NIMIN2 interact differentially with NPR1, thus providing a molecular basis for their opposing effects on NPR1. Together, our data suggest that the Arabidopsis NIMIN proteins are regulators of the SAR response. We propose that NIMINs act in a strictly consecutive and SA-regulated manner on the SA sensor protein NPR1, enabling NPR1 to monitor progressing threat by pathogens and to promote appropriate defense gene activation at distinct stages of SAR. In this scenario, the defense gene PR-1 is repressed at the onset of SAR by SA-induced, yet instable NIMIN1.

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

    Science.gov (United States)

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

    2011-01-01

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

  4. Characterization of the Ubiquitin E2 Enzyme Variant Gene Family in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Yu Zhang; Pei Wen; On-Sun Lau; Xing-Wang Deng

    2007-01-01

    Ubiquitin E2 enzyme variant (UEV) proteins are similar to ubiquitin-conjugating enzyme (E2) in both sequence and structure, but the lack of a catalytic cysteine residue renders them incapable of forming a thiolester linkage with ubiquitin. While the functional roles of several UEVs have been defined in yeast and animal systems, Arabidopsis COP10, a photomorphogenesis repressor, is the only UEV characterized in plants. Phylogenetic analysis revealed that the eight Arabidopsis UEV genes belong to three subfamilies.The expression of those genes is supported by either the presence of ESTs or RT-PCR analysis. We also characterized the other members of the COP10 subfamily, UEV2. Semi-quantitative RT-PCR analysis indicated that the UEV2 transcripts can be detected in most organs of Arabidopsis. Analysis of UEV2::GUS transgenic lines also showed its ubiquitous expression in nearly all the developmental stages of Arabidopsis.Transient expression analysis indicated that the sGFP-UEV2 fusion protein can localize to both the cytoplasm and nucleus. A T-DNA insertion mutant, uev2-1, which abolished the transcription of UEV2, displays no visible phenotype. Further, the cop10-4 uev2-1 double mutant exhibits the same phenotype as the cop10-4mutant in darkness. UEV2 is therefore not functionally redundant with COP10.

  5. 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.

  6. Mobility of the maize transposable element En/Spm in Arabidopsis thaliana.

    Science.gov (United States)

    Cardon, G H; Frey, M; Saedler, H; Gierl, A

    1993-06-01

    The autonomous element En-1 of the maize En/Spm transposable element system is capable of frequent somatic and germinal excision in the heterologous host Arabidopsis thaliana. The pattern of En-homologous transcripts generated in transgenic Arabidopsis resembles En transcription in maize. An excision reporter construct based on NPT-II gene (pKEn2) can be used reliably for the isolation of En-1 germinal revertants by seed germination on kanamycin-containing medium. Re-insertion after germinal excision is apparently frequent. A dSpm receptor element can be efficiently trans-activated in Arabidopsis either by En-1 or by expressing cDNAs of tnpA and tnpD. Excision and re-insertion of En/Spm take place with similar characteristics as in maize. This is the first description of En/Spm transposition in Arabidopsis and the parameters analysed here suggest that transposon tagging with En should be feasible in this species.

  7. A spatial dissection of the Arabidopsis floral transcriptome by MPSS

    Directory of Open Access Journals (Sweden)

    Sanchez-Leon Nidia

    2008-04-01

    Full Text Available Abstract Background We have further characterized floral organ-localized gene expression in the inflorescence of Arabidopsis thaliana by comparison of massively parallel signature sequencing (MPSS data. Six libraries of RNA sequence tags from immature inflorescence tissues were constructed and matched to their respective loci in the annotated Arabidopsis genome. These signature libraries survey the floral transcriptome of wild-type tissue as well as the floral homeotic mutants, apetala1, apetala3, agamous, a superman/apetala1 double mutant, and differentiated ovules dissected from the gynoecia of wild-type inflorescences. Comparing and contrasting these MPSS floral expression libraries enabled demarcation of transcripts enriched in the petals, stamens, stigma-style, gynoecia, and those with predicted enrichment within the sepal/sepal-petals, petal-stamens, or gynoecia-stamens. Results By comparison of expression libraries, a total of 572 genes were found to have organ-enriched expression within the inflorescence. The bulk of characterized organ-enriched transcript diversity was noted in the gynoecia and stamens, whereas fewer genes demonstrated sepal or petal-localized expression. Validation of the computational analyses was performed by comparison with previously published expression data, in situ hybridizations, promoter-reporter fusions, and reverse transcription PCR. A number of well-characterized genes were accurately delineated within our system of transcript filtration. Moreover, empirical validations confirm MPSS predictions for several genes with previously uncharacterized expression patterns. Conclusion This extensive MPSS analysis confirms and supplements prior microarray floral expression studies and illustrates the utility of sequence survey-based expression analysis in functional genomics. Spatial floral expression data accrued by MPSS and similar methods will be advantageous in the elucidation of more comprehensive genetic

  8. Novel disease susceptibility factors for fungal necrotrophic pathogens in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Albor Dobón

    2015-04-01

    Full Text Available Host cells use an intricate signaling system to respond to invasions by pathogenic microorganisms. Although several signaling components of disease resistance against necrotrophic fungal pathogens have been identified, our understanding for how molecular components and host processes contribute to plant disease susceptibility is rather sparse. Here, we identified four transcription factors (TFs from Arabidopsis that limit pathogen spread. Arabidopsis mutants defective in any of these TFs displayed increased disease susceptibility to Botrytis cinerea and Plectosphaerella cucumerina, and a general activation of non-immune host processes that contribute to plant disease susceptibility. Transcriptome analyses revealed that the mutants share a common transcriptional signature of 77 up-regulated genes. We characterized several of the up-regulated genes that encode peptides with a secretion signal, which we named PROVIR (for provirulence factors. Forward and reverse genetic analyses revealed that many of the PROVIRs are important for disease susceptibility of the host to fungal necrotrophs. The TFs and PROVIRs identified in our work thus represent novel genetic determinants for plant disease susceptibility to necrotrophic fungal pathogens.

  9. Exploiting Natural Variation in Arabidopsis

    NARCIS (Netherlands)

    Molenaar, J.A.; Keurentjes, J.J.B.

    2014-01-01

    Natural variation for many traits is present within the species Arabidopsis thaliana . This chapter describes the use of natural variation to elucidate genes underlying the regulation of quantitative traits. It deals with the development and use of mapping populations, the detection and handling of

  10. Exploiting natural variation in Arabidopsis

    NARCIS (Netherlands)

    J.A. Molenaar; J.J.B. Keurentjes

    2014-01-01

    Natural variation for many traits is present within the species Arabidopsis thaliana. This chapter describes the use of natural variation to elucidate genes underlying the regulation of quantitative traits. It deals with the development and use of mapping populations, the detection and handling of g

  11. The salty tale of Arabidopsis.

    Science.gov (United States)

    Sanders, D

    2000-06-29

    High concentrations of sodium chloride are toxic to most plant species. New insights into the mechanisms by which plants tolerate salt have emerged from the identification of genes in Arabidopsis thaliana that play a critical part in physiological resistance to salt.

  12. Transcriptional Regulation and Signaling in Phosphorus Starvation: What About Legumes?

    Institute of Scientific and Technical Information of China (English)

    Oswaldo Valdés-Lóppez; Georgina Hernández

    2008-01-01

    The availability of soil phosphorus (P), an essential element, is one of the most important requirements for plant growth and crop production. The morphological and physiological adaptations evolved by plants to cope with P starvation have been well characterized. Several P deficiency plant responses are regulated at the transcriptional level. Microarray analysis has generated valuable information on global gene expression in Arabidopsis thaliana grown under P-stress. Despite the identification of P responsive genes, little is known about the regulation of gene expression changes. Four transcription factors, PHR1, WRKY75, ZAT6 and BHLH32, involved in P starvation signaling have been characterized in Arabidopsis, and signaling pathways are deciphered. This review analyzes the current knowledge of transcriptional regulation of P starvation responses in Arabidopsis vis-a-vis legumes such as lupine, common bean and Medicago truncatula. The knowledge on regulatory and signaling mechanisms involved in P acquisition and use in legumes will be useful for improvement of these crops, which account for a large proportion of the world's crop production, providing good nutritional quality feed and food.

  13. Epigenetic Regulation of Intronic Transgenes in Arabidopsis

    Science.gov (United States)

    Osabe, Kenji; Harukawa, Yoshiko; Miura, Saori; Saze, Hidetoshi

    2017-01-01

    Defense mechanisms of plant genomes can epigenetically inactivate repetitive sequences and exogenous transgenes. Loss of mutant phenotypes in intronic T-DNA insertion lines by interaction with another T-DNA locus, termed T-DNA suppression, has been observed in Arabidopsis thaliana, although the molecular basis of establishment and maintenance of T-DNA suppression is poorly understood. Here we show that maintenance of T-DNA suppression requires heterochromatinisation of T-DNA sequences and the nuclear proteins, INCREASED IN BONSAI METHYLATION 2 (IBM2) and ENHANCED DOWNY MILDEW 2 (EDM2), which prevent ectopic 3′ end processing of mRNA in atypically long introns containing T-DNA sequences. Initiation of T-DNA suppression is mediated by the canonical RdDM pathway after hybridisation of two T-DNA strains, accompanied by DNA hypermethylation of T-DNA sequences in the F1 generation. Our results reveal the presence of a genome surveillance mechanism through genome hybridisation that masks repetitive DNAs intruding into transcription units. PMID:28338020

  14. NFXL2 modifies cuticle properties in Arabidopsis.

    Science.gov (United States)

    Lisso, Janina; Schröder, Florian; Schippers, Jos H M; Müssig, Carsten

    2012-05-01

    Loss of the Arabidopsis NFX1-LIKE2 (NFXL2) gene (At5g05660) results in elevated ABA levels, elevated hydrogen peroxide levels, reduced stomatal aperture, and enhanced drought stress tolerance. Introduction of the NFXL2-78 isoform into the nfxl2-1 mutant is largely sufficient for complementation of the phenotype. We show here that cuticular properties are altered in the nfxl2-1 mutant. The NFXL2-78 protein binds to the SHINE1 (SHN1), SHN2, SHN3, and BODYGUARD1 (BDG1) promoters and mediates weaker expression of these genes. The SHN AP2 domain transcription factors influence cuticle properties. Stronger SHN1, SHN2, and SHN3 expression in the nfxl2-1 mutant may cause altered cuticle properties including reduced stomatal density, and partly explain the enhanced drought stress tolerance. The BDG1 protein also controls cuticle development and is essential for osmotic stress regulation of ABA biosynthesis. Stronger BDG1 expression in nfxl2-1 plants may allow elevated ABA accumulation under drought stress. We conclude that the NFXL2-78 protein is part of a regulatory network that integrates the biosynthesis and action of ABA, ROS, and cuticle components.

  15. The WRKY57 Transcription Factor Affects the Expression of Jasmonate ZIM-Domain Genes Transcriptionally to Compromise Botrytis cinerea Resistance.

    Science.gov (United States)

    Jiang, Yanjuan; Yu, Diqiu

    2016-08-01

    Although necrotrophic pathogens cause many devastating plant diseases, our understanding of the plant defense response to them is limited. Here, we found that loss of function of WRKY57 enhanced the resistance of Arabidopsis (Arabidopsis thaliana) against Botrytis cinerea infection. Further investigation suggested that the negative regulation of WRKY57 against B cinerea depends on the jasmonic acid (JA) signaling pathway. Chromatin immunoprecipitation experiments revealed that WRKY57 directly binds to the promoters of JASMONATE ZIM-DOMAIN1 (JAZ1) and JAZ5, encoding two important repressors of the JA signaling pathway, and activates their transcription. In vivo and in vitro experiments demonstrated that WRKY57 interacts with nuclear-encoded SIGMA FACTOR BINDING PROTEIN1 (SIB1) and SIB2. Further experiments display that the same domain, the VQ motif, of SIB1 and SIB2 interact with WRKY33 and WRKY57. Moreover, transient transcriptional activity assays confirmed that WRKY57 and WRKY33 competitively regulate JAZ1 and JAZ5, SIB1 and SIB2 further enhance these competitions of WRKY57 to WRKY33. Therefore, coordinated regulation of Arabidopsis against B cinerea by transcription activators and repressors would benefit plants by allowing fine regulation of defense.

  16. Arabidopsis late blight: infection of a nonhost plant by Albugo laibachii enables full colonization by Phytophthora infestans.

    Science.gov (United States)

    Belhaj, Khaoula; Cano, Liliana M; Prince, David C; Kemen, Ariane; Yoshida, Kentaro; Dagdas, Yasin F; Etherington, Graham J; Schoonbeek, Henk-Jan; van Esse, H Peter; Jones, Jonathan D G; Kamoun, Sophien; Schornack, Sebastian

    2017-01-01

    The oomycete pathogen Phytophthora infestans causes potato late blight, and as a potato and tomato specialist pathogen, is seemingly poorly adapted to infect plants outside the Solanaceae. Here, we report the unexpected finding that P. infestans can infect Arabidopsis thaliana when another oomycete pathogen, Albugo laibachii, has colonized the host plant. The behaviour and speed of P. infestans infection in Arabidopsis pre-infected with A. laibachii resemble P. infestans infection of susceptible potato plants. Transcriptional profiling of P. infestans genes during infection revealed a significant overlap in the sets of secreted-protein genes that are induced in P. infestans upon colonization of potato and susceptible Arabidopsis, suggesting major similarities in P. infestans gene expression dynamics on the two plant species. Furthermore, we found haustoria of A. laibachii and P. infestans within the same Arabidopsis cells. This Arabidopsis-A. laibachii-P. infestans tripartite interaction opens up various possibilities to dissect the molecular mechanisms of P. infestans infection and the processes occurring in co-infected Arabidopsis cells.

  17. Comprehensive analysis of alternative splicing in rice and comparative analyses with Arabidopsis

    Directory of Open Access Journals (Sweden)

    Mount Stephen M

    2006-12-01

    Full Text Available Abstract Background Recently, genomic sequencing efforts were finished for Oryza sativa (cultivated rice and Arabidopsis thaliana (Arabidopsis. Additionally, these two plant species have extensive cDNA and expressed sequence tag (EST libraries. We employed the Program to Assemble Spliced Alignments (PASA to identify and analyze alternatively spliced isoforms in both species. Results A comprehensive analysis of alternative splicing was performed in rice that started with >1.1 million publicly available spliced ESTs and over 30,000 full length cDNAs in conjunction with the newly enhanced PASA software. A parallel analysis was performed with Arabidopsis to compare and ascertain potential differences between monocots and dicots. Alternative splicing is a widespread phenomenon (observed in greater than 30% of the loci with transcript support and we have described nine alternative splicing variations. While alternative splicing has the potential to create many RNA isoforms from a single locus, the majority of loci generate only two or three isoforms and transcript support indicates that these isoforms are generally not rare events. For the alternate donor (AD and acceptor (AA classes, the distance between the splice sites for the majority of events was found to be less than 50 basepairs (bp. In both species, the most frequent distance between AA is 3 bp, consistent with reports in mammalian systems. Conversely, the most frequent distance between AD is 4 bp in both plant species, as previously observed in mouse. Most alternative splicing variations are localized to the protein coding sequence and are predicted to significantly alter the coding sequence. Conclusion Alternative splicing is widespread in both rice and Arabidopsis and these species share many common features. Interestingly, alternative splicing may play a role beyond creating novel combinations of transcripts that expand the proteome. Many isoforms will presumably have negative

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

    OpenAIRE

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

    2015-01-01

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

  19. Functional analysis of the theobroma cacao NPR1 gene in arabidopsis

    Directory of Open Access Journals (Sweden)

    Verica Joseph

    2010-11-01

    Full Text Available Abstract Background The Arabidopsis thaliana NPR1 gene encodes a transcription coactivator (NPR1 that plays a major role in the mechanisms regulating plant defense response. After pathogen infection and in response to salicylic acid (SA accumulation, NPR1 translocates from the cytoplasm into the nucleus where it interacts with other transcription factors resulting in increased expression of over 2000 plant defense genes contributing to a pathogen resistance response. Results A putative Theobroma cacao NPR1 cDNA was isolated by RT-PCR using degenerate primers based on homologous sequences from Brassica, Arabidopsis and Carica papaya. The cDNA was used to isolate a genomic clone from Theobroma cacao containing a putative TcNPR1 gene. DNA sequencing revealed the presence of a 4.5 kb coding region containing three introns and encoding a polypeptide of 591 amino acids. The predicted TcNPR1 protein shares 55% identity and 78% similarity to Arabidopsis NPR1, and contains each of the highly conserved functional domains indicative of this class of transcription factors (BTB/POZ and ankyrin repeat protein-protein interaction domains and a nuclear localization sequence (NLS. To functionally define the TcNPR1 gene, we transferred TcNPR1 into an Arabidopsis npr1 mutant that is highly susceptible to infection by the plant pathogen Pseudomonas syringae pv. tomato DC3000. Driven by the constitutive CaMV35S promoter, the cacao TcNPR1 gene partially complemented the npr1 mutation in transgenic Arabidopsis plants, resulting in 100 fold less bacterial growth in a leaf infection assay. Upon induction with SA, TcNPR1 was shown to translocate into the nucleus of leaf and root cells in a manner identical to Arabidopsis NPR1. Cacao NPR1 was also capable of participating in SA-JA signaling crosstalk, as evidenced by the suppression of JA responsive gene expression in TcNPR1 overexpressing transgenic plants. Conclusion Our data indicate that the TcNPR1 is a functional

  20. SUPPRESSOR OF APICAL DOMINANCE1 of Sporisorium reilianum Modulates Inflorescence Branching Architecture in Maize and Arabidopsis.

    Science.gov (United States)

    Ghareeb, Hassan; Drechsler, Frank; Löfke, Christian; Teichmann, Thomas; Schirawski, Jan

    2015-12-01

    The biotrophic fungus Sporisorium reilianum causes head smut of maize (Zea mays) after systemic plant colonization. Symptoms include the formation of multiple female inflorescences at subapical nodes of the stalk because of loss of apical dominance. By deletion analysis of cluster 19-1, the largest genomic divergence cluster in S. reilianum, we identified a secreted fungal effector responsible for S. reilianum-induced loss of apical dominance, which we named SUPPRESSOR OF APICAL DOMINANCE1 (SAD1). SAD1 transcript levels were highly up-regulated during biotrophic fungal growth in all infected plant tissues. SAD1-green fluorescent protein fusion proteins expressed by recombinant S. reilianum localized to the extracellular hyphal space. Transgenic Arabidopsis (Arabidopsis thaliana)-expressing green fluorescent protein-SAD1 displayed an increased number of secondary rosette-leaf branches. This suggests that SAD1 manipulates inflorescence branching architecture in maize and Arabidopsis through a conserved pathway. Using a yeast (Saccharomyces cerevisiae) two-hybrid library of S. reilianum-infected maize tissues, we identified potential plant interaction partners that had a predicted function in ubiquitination, signaling, and nuclear processes. Presence of SAD1 led to an increase of the transcript levels of the auxin transporter PIN-FORMED1 in the root and a reduction of the branching regulator TEOSINTE BRANCHED1 in the stalk. This indicates a role of SAD1 in regulation of apical dominance by modulation of branching through increasing transcript levels of the auxin transporter PIN1 and derepression of bud outgrowth.

  1. DNA binding by the plant-specific NAC transcription factors in crystal and solution

    DEFF Research Database (Denmark)

    Welner, Ditte Hededam; Lindemose, Søren; Grossmann, J. Günter;

    2012-01-01

    NAC (NAM/ATAF/CUC) plant transcription factors regulate essential processes in development, stress responses and nutrient distribution in important crop and model plants (rice, Populus, Arabidopsis), which makes them highly relevant in the context of crop optimization and bioenergy production. Th...

  2. Transcriptomic analysis of the role of carboxylic acids in metabolite signaling in Arabidopsis leaves.

    Science.gov (United States)

    Finkemeier, Iris; König, Ann-Christine; Heard, William; Nunes-Nesi, Adriano; Pham, Phuong Anh; Leister, Dario; Fernie, Alisdair R; Sweetlove, Lee J

    2013-05-01

    The transcriptional response to metabolites is an important mechanism by which plants integrate information about cellular energy and nutrient status. Although some carboxylic acids have been implicated in the regulation of gene expression for select transcripts, it is unclear whether all carboxylic acids have the same effect, how many transcripts are affected, and how carboxylic acid signaling is integrated with other metabolite signals. In this study, we demonstrate that perturbations in cellular concentrations of citrate, and to a lesser extent malate, have a major impact on nucleus-encoded transcript abundance. Functional categories of transcripts that were targeted by both organic acids included photosynthesis, cell wall, biotic stress, and protein synthesis. Specific functional categories that were only regulated by citrate included tricarboxylic acid cycle, nitrogen metabolism, sulfur metabolism, and DNA synthesis. Further quantitative real-time polymerase chain reaction analysis of specific citrate-responsive transcripts demonstrated that the transcript response to citrate is time and concentration dependent and distinct from other organic acids and sugars. Feeding of isocitrate as well as the nonmetabolizable citrate analog tricarballylate revealed that the abundance of selected marker transcripts is responsive to citrate and not downstream metabolites. Interestingly, the transcriptome response to citrate feeding was most similar to those observed after biotic stress treatments and the gibberellin biosynthesis inhibitor paclobutrazol. Feeding of citrate to mutants with defects in plant hormone signaling pathways did not completely abolish the transcript response but hinted at a link with jasmonic acid and gibberellin signaling pathways. Our results suggest that changes in carboxylic acid abundances can be perceived and signaled in Arabidopsis (Arabidopsis thaliana) by as yet unknown signaling pathways.

  3. Complex processing patterns of mRNAs of the large ATP synthase operon in Arabidopsis chloroplasts.

    Directory of Open Access Journals (Sweden)

    Mustafa Malik Ghulam

    Full Text Available Chloroplasts are photosynthetic cell organelles which have evolved from endosymbiosis of the cyanobacterial ancestor. In chloroplasts, genes are still organized into transcriptional units as in bacteria but the corresponding poly-cistronic mRNAs undergo complex processing events, including inter-genic cleavage and 5' and 3' end-definition. The current model for processing proposes that the 3' end of the upstream cistron transcripts and the 5' end of the downstream cistron transcripts are defined by the same RNA-binding protein and overlap at the level of the protein-binding site. We have investigated the processing mechanisms that operate within the large ATP synthase (atp operon, in Arabidopsis thaliana chloroplasts. This operon is transcribed by the plastid-encoded RNA polymerase starting from two promoters, which are upstream and within the operon, respectively, and harbors four potential sites for RNA-binding proteins. In order to study the functional significance of the promoters and the protein-binding sites for the maturation processes, we have performed a detailed mapping of the atp transcript ends. Our data indicate that in contrast to maize, atpI and atpH transcripts with overlapping ends are very rare in Arabidopsis. In addition, atpA mRNAs, which overlap with atpF mRNAs, are even truncated at the 3' end, thus representing degradation products. We observe, instead, that the 5' ends of nascent poly-cistronic atp transcripts are defined at the first protein-binding site which follows either one of the two transcription initiation sites, while the 3' ends are defined at the subsequent protein-binding sites or at hairpin structures that are encountered by the progressing RNA polymerase. We conclude that the overlapping mechanisms of mRNA protection have only a limited role in obtaining stable processed atp mRNAs in Arabidopsis. Our findings suggest that during evolution of different plant species as maize and Arabidopsis, chloroplasts

  4. Erasure of CpG methylation in Arabidopsis alters patterns of histone H3 methylation in heterochromatin

    DEFF Research Database (Denmark)

    Tariq, M.; Saze, H.; Probst, A.;

    2003-01-01

    DNA methylation to histone methylation, however, is less understood. Its recent examination in Arabidopsis with a partial loss of function in DNA methyltransferase 1 (responsible for maintenance of CpG methylation) yielded conflicting results. Here we report that complete removal of CpG methylation...... in an Arabidopsis mutant null for DNA maintenance methyltransferase results in a clear loss of histone H3 methylation at lysine 9 in heterochromatin and also at heterochromatic loci that remain transcriptionally silent. Surprisingly, these dramatic alterations are not reflected in heterochromatin relaxation....

  5. An NAC transcription factor controls ethylene-regulated cell expansion in flower petals.

    Science.gov (United States)

    Pei, Haixia; Ma, Nan; Tian, Ji; Luo, Jing; Chen, Jiwei; Li, Jing; Zheng, Yi; Chen, Xiang; Fei, Zhangjun; Gao, Junping

    2013-10-01

    Cell expansion is crucial for plant growth. It is well known that the phytohormone ethylene functions in plant development as a key modulator of cell expansion. However, the role of ethylene in the regulation of this process remains unclear. In this study, 2,189 ethylene-responsive transcripts were identified in rose (Rosa hybrida) petals using transcriptome sequencing and microarray analysis. Among these transcripts, an NAC (for no apical meristem [NAM], Arabidopsis transcription activation factor [ATAF], and cup-shaped cotyledon [CUC])-domain transcription factor gene, RhNAC100, was rapidly and dramatically induced by ethylene in the petals. Interestingly, accumulation of the RhNAC100 transcript was modulated by ethylene via microRNA164-dependent posttranscriptional regulation. Overexpression of RhNAC100 in Arabidopsis (Arabidopsis thaliana) substantially reduced the petal size by repressing petal cell expansion. By contrast, silencing of RhNAC100 in rose petals using virus-induced gene silencing significantly increased petal size and promoted cell expansion in the petal abaxial subepidermis (P cellulose synthase and two aquaporin genes (Rosa hybrida Cellulose Synthase2 and R. hybrida Plasma Membrane Intrinsic Protein1;1/2;1) were identified as targets of RhNAC100. Our results suggest that ethylene regulates cell expansion by fine-tuning the microRNA164/RhNAC100 module and also provide new insights into the function of NAC transcription factors.

  6. Zinc finger artificial transcription factor-based nearest inactive analogue/nearest active analogue strategy used for the identification of plant genes controlling homologous recombination

    NARCIS (Netherlands)

    Jia, Qi; van Verk, Marcel C.; Pinas, Johan E.; Lindhout, Beatrice I.; Hooykaas, Paul J.J.; Van der Zaal, Bert J.

    2013-01-01

    In previous work, we selected a particular transcription factor, designated VP16-HRU, from a pool of zinc finger artificial transcription factors (ZF-ATFs) used for genome interrogation. When expressed in Arabidopsis thaliana under control of the ribosomal protein S5A promoter, the RPS5A::VP16-HRU c

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

    Directory of Open Access Journals (Sweden)

    Mesfin Tesfaye

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

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

    Science.gov (United States)

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

    2013-01-01

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

  9. Evidences for involvement of endogenous cAMP in Arabidopsis defense responses to Verticillium toxins

    Institute of Scientific and Technical Information of China (English)

    Jing JIANG; Ling Wen FAN; Wei Hua WU

    2005-01-01

    Although there were reports suggesting the involvement of endogenous cAMP in plant defense signaling cascades,there is no direct evidence supporting this notion yet and the detailed mechanism is unclear. In the present study, we have used pathogenic fungi Verticillium dahliae and Arabidopsis plants as a model system of plant-microb interaction to demonstrate the function of endogenous cAMP in Arabidopsis defense responses. Both V. dahliae inoculation and Verticillium toxins injection induced typical "wilt" symptoms in Arabidopsis seedlings. When either 8-Br-AMP (a membrane permeable cAMP analogue) or salicylic acid (SA) was applied to Arabidopsis, the plants became resistant to V. dahliae toxins. However, addition of 8-Br-AMP did not increase the resistance of Arabidopsis transgenic plants deficient in SA to the toxins, suggesting that cAMP might act upstream of SA in plant defense signaling pathway.Indeed, 8-Br-cAMP and forskolin, an activator of adenylyl cyclase, significantly stimulated the endogenous SA level in plants, whereas DDA, an inhibitor of adenylyl cyclase dramatically reduced toxin-induced SA increase. Both the endogenous cAMP and SA increased significantly in Arabidopsis seedlings treated with toxins. Furthermore, transcription level of pathogenesis-related protein 1 gene (PR1) was strongly induced by both 8-Br-cAMP and the toxin treatment. Taken together, our data demonstrate that endogenous cAMP is involved in plant defense responses against Verticilliumsecreted toxins by regulating the production of the known signal SA in plant defense pathway.

  10. Analysis of metabolic alterations in Arabidopsis following changes in the carbon dioxide and oxygen partial pressures

    Institute of Scientific and Technical Information of China (English)

    Alexandra Florian; Stefan Timm; Zoran Nikoloski; Takayuki Tohge; Hermann Bauwe; Wagner LArajo; Alisdair RFernie

    2014-01-01

    As sessile organisms, plants are subject to a multitude of environmental variations including several which directly affect their interaction with the atmosphere. Given the indiscriminant nature of Rubisco, the relative rates of photosynthesis and photorespiration are known to be responsive to changes in gas composition. However, compre-hensive profiling methods have not yet been applied in order to characterize the wider consequences of these changes on primary metabolism in general. Moreover, although transcrip-tional profiling has revealed that a subset of photorespiratory enzymes are co-expressed, whether transcriptional responses play a role in short-term responses to atmospheric composi-tional changes remains unknown. To address these questions, plants Arabidopsis thaliana (Arabidopsis) ecotype Columbia (Col-O) grown under normal air conditions were transferred to different CO2 and O2 concentrations and characterized at the physiological, molecular, and metabolic levels fol owing this transition. The results reveal alterations in the components, which are directly involved in, or supporting, photorespiration, including transcripts and metabolite levels. The results further highlight that the majority of the regulation of these pathways is not mediated at the level of transcription and that the photorespiratory pathway is essential also in conditions in which flux through the pathway is minimized, yet suggest that flux through this pathway is not mediated at the level of transcription.

  11. Analysis of ripening-related gene expression in papaya using an Arabidopsis-based microarray

    Directory of Open Access Journals (Sweden)

    Fabi João Paulo

    2012-12-01

    Full Text Available Abstract Background Papaya (Carica papaya L. is a commercially important crop that produces climacteric fruits with a soft and sweet pulp that contain a wide range of health promoting phytochemicals. Despite its importance, little is known about transcriptional modifications during papaya fruit ripening and their control. In this study we report the analysis of ripe papaya transcriptome by using a cross-species (XSpecies microarray technique based on the phylogenetic proximity between papaya and Arabidopsis thaliana. Results Papaya transcriptome analyses resulted in the identification of 414 ripening-related genes with some having their expression validated by qPCR. The transcription profile was compared with that from ripening tomato and grape. There were many similarities between papaya and tomato especially with respect to the expression of genes encoding proteins involved in primary metabolism, regulation of transcription, biotic and abiotic stress and cell wall metabolism. XSpecies microarray data indicated that transcription factors (TFs of the MADS-box, NAC and AP2/ERF gene families were involved in the control of papaya ripening and revealed that cell wall-related gene expression in papaya had similarities to the expression profiles seen in Arabidopsis during hypocotyl development. Conclusion The cross-species array experiment identified a ripening-related set of genes in papaya allowing the comparison of transcription control between papaya and other fruit bearing taxa during the ripening process.

  12. An International Bioinformatics Infrastructure to Underpin the Arabidopsis Community

    Science.gov (United States)

    The future bioinformatics needs of the Arabidopsis community as well as those of other scientific communities that depend on Arabidopsis resources were discussed at a pair of recent meetings held by the Multinational Arabidopsis Steering Committee (MASC) and the North American Arabidopsis Steering C...

  13. Arabidopsis CDS blastp result: AK240652 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK240652 J023098G11 At5g63090.2 68418.m07919 LOB domain protein / lateral organ boundaries... protein (LOB) identical to LOBa [Arabidopsis thaliana] GI:17484100, SP|Q9FML4 LATERAL ORGAN BOUNDARIES protein {Arabidopsis thaliana} 1e-13 ...

  14. Arabidopsis CDS blastp result: AK241761 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK241761 J065205C18 At5g63090.1 68418.m07918 LOB domain protein / lateral organ boundaries... protein (LOB) identical to LOBa [Arabidopsis thaliana] GI:17484100, SP|Q9FML4 LATERAL ORGAN BOUNDARIES protein {Arabidopsis thaliana} 5e-32 ...

  15. Arabidopsis CDS blastp result: AK240652 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK240652 J023098G11 At5g63090.1 68418.m07918 LOB domain protein / lateral organ boundaries... protein (LOB) identical to LOBa [Arabidopsis thaliana] GI:17484100, SP|Q9FML4 LATERAL ORGAN BOUNDARIES protein {Arabidopsis thaliana} 1e-13 ...

  16. Arabidopsis CDS blastp result: AK240652 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK240652 J023098G11 At5g63090.4 68418.m07921 LOB domain protein / lateral organ boundaries... protein (LOB) identical to LOBa [Arabidopsis thaliana] GI:17484100, SP|Q9FML4 LATERAL ORGAN BOUNDARIES protein {Arabidopsis thaliana} 1e-13 ...

  17. Arabidopsis CDS blastp result: AK241761 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK241761 J065205C18 At5g63090.3 68418.m07920 LOB domain protein / lateral organ boundaries... protein (LOB) identical to LOBa [Arabidopsis thaliana] GI:17484100, SP|Q9FML4 LATERAL ORGAN BOUNDARIES protein {Arabidopsis thaliana} 5e-32 ...

  18. Arabidopsis CDS blastp result: AK241761 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK241761 J065205C18 At5g63090.2 68418.m07919 LOB domain protein / lateral organ boundaries... protein (LOB) identical to LOBa [Arabidopsis thaliana] GI:17484100, SP|Q9FML4 LATERAL ORGAN BOUNDARIES protein {Arabidopsis thaliana} 5e-32 ...

  19. Arabidopsis CDS blastp result: AK241761 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK241761 J065205C18 At5g63090.4 68418.m07921 LOB domain protein / lateral organ boundaries... protein (LOB) identical to LOBa [Arabidopsis thaliana] GI:17484100, SP|Q9FML4 LATERAL ORGAN BOUNDARIES protein {Arabidopsis thaliana} 5e-32 ...

  20. Arabidopsis CDS blastp result: AK240652 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK240652 J023098G11 At5g63090.3 68418.m07920 LOB domain protein / lateral organ boundaries... protein (LOB) identical to LOBa [Arabidopsis thaliana] GI:17484100, SP|Q9FML4 LATERAL ORGAN BOUNDARIES protein {Arabidopsis thaliana} 1e-13 ...

  1. Arabidopsis CDS blastp result: AK105527 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK105527 001-127-G05 At5g63090.4 LOB domain protein / lateral organ boundaries prot...ein (LOB) identical to LOBa [Arabidopsis thaliana] GI:17484100, SP|Q9FML4 LATERAL ORGAN BOUNDARIES protein {Arabidopsis thaliana} 3e-52 ...

  2. Using "Arabidopsis" Genetic Sequences to Teach Bioinformatics

    Science.gov (United States)

    Zhang, Xiaorong

    2009-01-01

    This article describes a new approach to teaching bioinformatics using "Arabidopsis" genetic sequences. Several open-ended and inquiry-based laboratory exercises have been designed to help students grasp key concepts and gain practical skills in bioinformatics, using "Arabidopsis" leucine-rich repeat receptor-like kinase (LRR…

  3. Arabidopsis CDS blastp result: AK240730 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK240730 J043030K09 At2g32440.1 68415.m03963 ent-kaurenoic acid hydroxylase, putati...ve / cytochrome P450, putative identical to ent-kaurenoic acid hydroxylase / cytochrome P450 CYP88A (GI:1302...1856) [Arabidopsis thaliana]; similar to ent-kaurenoic acid hydroxylase [Arabidopsis thaliana] GI:13021853 2e-11 ...

  4. Arabidopsis CDS blastp result: AK288052 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK288052 J075151I09 At2g32440.1 68415.m03963 ent-kaurenoic acid hydroxylase, putati...ve / cytochrome P450, putative identical to ent-kaurenoic acid hydroxylase / cytochrome P450 CYP88A (GI:1302...1856) [Arabidopsis thaliana]; similar to ent-kaurenoic acid hydroxylase [Arabidopsis thaliana] GI:13021853 6e-14 ...

  5. Arabidopsis CDS blastp result: AK240911 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK240911 J065037E05 At2g32440.1 68415.m03963 ent-kaurenoic acid hydroxylase, putati...ve / cytochrome P450, putative identical to ent-kaurenoic acid hydroxylase / cytochrome P450 CYP88A (GI:1302...1856) [Arabidopsis thaliana]; similar to ent-kaurenoic acid hydroxylase [Arabidopsis thaliana] GI:13021853 4e-22 ...

  6. Arabidopsis CDS blastp result: AK241119 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK241119 J065094C22 At2g32440.1 68415.m03963 ent-kaurenoic acid hydroxylase, putati...ve / cytochrome P450, putative identical to ent-kaurenoic acid hydroxylase / cytochrome P450 CYP88A (GI:1302...1856) [Arabidopsis thaliana]; similar to ent-kaurenoic acid hydroxylase [Arabidopsis thaliana] GI:13021853 2e-13 ...

  7. Arabidopsis CDS blastp result: AK243149 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK243149 J100032I21 At2g32440.1 68415.m03963 ent-kaurenoic acid hydroxylase, putati...ve / cytochrome P450, putative identical to ent-kaurenoic acid hydroxylase / cytochrome P450 CYP88A (GI:1302...1856) [Arabidopsis thaliana]; similar to ent-kaurenoic acid hydroxylase [Arabidopsis thaliana] GI:13021853 7e-12 ...

  8. Arabidopsis CDS blastp result: AK241581 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK241581 J065181K09 At2g32440.1 68415.m03963 ent-kaurenoic acid hydroxylase, putati...ve / cytochrome P450, putative identical to ent-kaurenoic acid hydroxylase / cytochrome P450 CYP88A (GI:1302...1856) [Arabidopsis thaliana]; similar to ent-kaurenoic acid hydroxylase [Arabidopsis thaliana] GI:13021853 4e-15 ...

  9. Arabidopsis CDS blastp result: AK287479 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK287479 J043023O14 At2g32440.1 68415.m03963 ent-kaurenoic acid hydroxylase, putati...ve / cytochrome P450, putative identical to ent-kaurenoic acid hydroxylase / cytochrome P450 CYP88A (GI:1302...1856) [Arabidopsis thaliana]; similar to ent-kaurenoic acid hydroxylase [Arabidopsis thaliana] GI:13021853 1e-17 ...

  10. Reference: 631 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available ggest that atRZ-1a has a negative impact on seed germination and seedling growth of Arabidopsis under salt o...binding protein, atRZ-1a, has a negative impact on seed germination and seedling growth of Arabidopsis thali

  11. TRANSFAC and its module TRANSCompel: transcriptional gene regulation in eukaryotes.

    Science.gov (United States)

    Matys, V; Kel-Margoulis, O V; Fricke, E; Liebich, I; Land, S; Barre-Dirrie, A; Reuter, I; Chekmenev, D; Krull, M; Hornischer, K; Voss, N; Stegmaier, P; Lewicki-Potapov, B; Saxel, H; Kel, A E; Wingender, E

    2006-01-01

    The TRANSFAC database on transcription factors, their binding sites, nucleotide distribution matrices and regulated genes as well as the complementing database TRANSCompel on composite elements have been further enhanced on various levels. A new web interface with different search options and integrated versions of Match and Patch provides increased functionality for TRANSFAC. The list of databases which are linked to the common GENE table of TRANSFAC and TRANSCompel has been extended by: Ensembl, UniGene, EntrezGene, HumanPSD and TRANSPRO. Standard gene names from HGNC, MGI and RGD, are included for human, mouse and rat genes, respectively. With the help of InterProScan, Pfam, SMART and PROSITE domains are assigned automatically to the protein sequences of the transcription factors. TRANSCompel contains now, in addition to the COMPEL table, a separate table for detailed information on the experimental EVIDENCE on which the composite elements are based. Finally, for TRANSFAC, in respect of data growth, in particular the gain of Drosophila transcription factor binding sites (by courtesy of the Drosophila DNase I footprint database) and of Arabidopsis factors (by courtesy of DATF, Database of Arabidopsis Transcription Factors) has to be stressed. The here described public releases, TRANSFAC 7.0 and TRANSCompel 7.0, are accessible under http://www.gene-regulation.com/pub/databases.html.

  12. Putrescine regulating by stress-responsive MAPK cascade contributes to bacterial pathogen defense in Arabidopsis.

    Science.gov (United States)

    Kim, Su-Hyun; Kim, Sun-Hwa; Yoo, Seung-Jin; Min, Kwang-Hyun; Nam, Seung-Hee; Cho, Baik Ho; Yang, Kwang-Yeol

    2013-08-09

    Polyamines in plants are involved in various physiological and developmental processes including abiotic and biotic stress responses. We investigated the expression of ADCs, which are key enzymes in putrescine (Put) biosynthesis, and roles of Put involving defense response in Arabidopsis. The increased expression of ADC1 and ADC2, and the induction of Put were detected in GVG-NtMEK2(DD) transgenic Arabidopsis, whereas, their performance was partially compromised in GVG-NtMEK2(DD)/mpk3 and GVG-NtMEK2(DD)/mpk6 mutant following DEX treatment. The expression of ADC2 was highly induced by Pst DC3000 inoculation, while the transcript levels of ADC1 were slightly up-regulated. Compared to the WT plant, Put content in the adc2 knock-out mutant was reduced after Pst DC3000 inoculation, and showed enhanced susceptibility to pathogen infection. The adc2 mutant exhibited reduced expression of PR-1 after bacterial infection and the growth of the pathogen was about 4-fold more than that in the WT plant. Furthermore, the disease susceptibility of the adc2 mutant was recovered by the addition of exogenous Put. Taken together, these results suggest that Arabidopsis MPK3 and MPK6 play a positive role in the regulation of Put biosynthesis, and that Put contributes to bacterial pathogen defense in Arabidopsis.

  13. Folic acid induces salicylic acid-dependent immunity in Arabidopsis and enhances susceptibility to Alternaria brassicicola.

    Science.gov (United States)

    Wittek, Finni; Kanawati, Basem; Wenig, Marion; Hoffmann, Thomas; Franz-Oberdorf, Katrin; Schwab, Wilfried; Schmitt-Kopplin, Philippe; Vlot, A Corina

    2015-08-01

    Folates are essential for one-carbon transfer reactions in all organisms and contribute, for example, to de novo DNA synthesis. Here, we detected the folate precursors 7,8-dihydropteroate (DHP) and 4-amino-4-deoxychorismate (ADC) in extracts from Arabidopsis thaliana plants by Fourier transform ion cyclotron resonance-mass spectrometry. The accumulation of DHP, but not ADC, was induced after infection of plants with Pseudomonas syringae delivering the effector protein AvrRpm1. Application of folic acid or the DHP precursor 7,8-dihydroneopterin (DHN) enhanced resistance in Arabidopsis to P. syringae and elevated the transcript accumulation of the salicylic acid (SA) marker gene pathogenesis-related1 in both the treated and systemic untreated leaves. DHN- and folic acid-induced systemic resistance was dependent on SA biosynthesis and signalling. Similar to SA, folic acid application locally enhanced Arabidopsis susceptibility to the necrotrophic fungus Alternaria brassicicola. Together, the data associate the folic acid pathway with innate immunity in Arabidopsis, simultaneously activating local and systemic SA-dependent resistance to P. syringae and suppressing local resistance to A. brassicicola.

  14. Overexpression of Nelumbo nucifera metallothioneins 2a and 3 enhances seed germination vigor in Arabidopsis.

    Science.gov (United States)

    Zhou, Yuliang; Chu, Pu; Chen, Huhui; Li, Yin; Liu, Jun; Ding, Yu; Tsang, Edward W T; Jiang, Liwen; Wu, Keqiang; Huang, Shangzhi

    2012-03-01

    Metallothioneins (MTs) are small, cysteine-rich and metal-binding proteins which are involved in metal homeostasis and scavenging of reactive oxygen species. Although plant MTs have been intensively studied, their roles in seeds remain to be clearly established. Here, we report the isolation and characterization of NnMT2a, NnMT2b and NnMT3 from sacred lotus (Nelumbo nucifera Gaertn.) and their roles in seed germination vigor. The transcripts of NnMT2a, NnMT2b and NnMT3 were highly expressed in developing and germinating sacred lotus seeds, and were dramatically up-regulated in response to high salinity, oxidative stresses and heavy metals. Analysis of transformed Arabidopsis protoplasts showed that NnMT2a-YFP and NnMT3-YFP were localized in cytoplasm and nucleoplasm. Transgenic Arabidopsis seeds overexpressing NnMT2a and NnMT3 displayed improved resistance to accelerated aging (AA) treatment, indicating their significant roles in seed germination vigor. These transgenic seeds also exhibited higher superoxide dismutase activity compared to wild-type seeds after AA treatment. In addition, we showed that NnMT2a and NnMT3 conferred improved germination ability to NaCl and methyl viologen on transgenic Arabidopsis seeds. Taken together, these data demonstrate that overexpression of NnMT2a and NnMT3 in Arabidopsis significantly enhances seed germination vigor after AA treatment and under abiotic stresses.

  15. The petunia ortholog of Arabidopsis SUPERMAN plays a distinct role in floral organ morphogenesis.

    Science.gov (United States)

    Nakagawa, Hitoshi; Ferrario, Silvia; Angenent, Gerco C; Kobayashi, Akira; Takatsuji, Hiroshi

    2004-04-01

    Arabidopsis (Arabidopsis thaliana) SUPERMAN (SUP) plays a role in establishing a boundary between whorls 3 and 4 of flowers and in ovule development. We characterized a Petunia hybrida (petunia) homolog of SUP, designated PhSUP1, to compare with SUP. Genomic DNA of the PhSUP1 partially restored the stamen number and ovule development phenotypes of the Arabidopsis sup mutant. Two P. hybrida lines of transposon (dTph1) insertion mutants of PhSUP1 exhibited increased stamen number at the cost of normal carpel development, and ovule development was defective owing to aberrant growth of the integument. Unlike Arabidopsis sup mutants, phsup1 mutants also showed extra tissues connecting stamens, a petal tube and an ovary, and aberrancies in the development of anther and placenta. PhSUP1 transcripts occurred in the basal region of wild-type flowers around developing organ primordia in whorls 2 and 3 as well as in the funiculus of the ovule, concave regions of the placenta, and interthecal regions of developing anthers. Overexpression of PhSUP1 in P. hybrida resulted in size reduction of petals, leaves, and inflorescence stems. The shortening of inflorescence stems and petal tubes was primarily attributable to suppression of cell elongation, whereas a decrease in cell number was mainly responsible for the size reduction of petal limbs.

  16. Fruit preferential activity of the tomato RIP1 gene promoter in transgenic tomato and Arabidopsis.

    Science.gov (United States)

    Agarwal, Priyanka; Kumar, Rahul; Pareek, Amit; Sharma, Arun K

    2017-02-01

    Isolation and functional characterization of tissue- and stage-specific gene promoters is beneficial for genetic improvement of economically important crops. Here, we have characterized a putative promoter of a ripening-induced gene RIP1 (Ripening induced protein 1) in tomato. Quantification of the transcript level of RIP1 showed that its expression is fruit preferential, with maximum accumulation in red ripe fruits. To test the promoter activity, we made a reporter construct by cloning 1450 bp putative RIP1 promoter driving the GUS (ß-glucuronidase) gene expression and generated stable transgenic lines in tomato and Arabidopsis. Histochemical and fluorometric assays validated the fruit-specific expression of RIP1 as the highest GUS activity was found in red ripe tomatoes. Similarly, we detected high levels of GUS activity in the siliques of Arabidopsis. On the contrary, weak GUS activity was found in the flower buds in both tomato and Arabidopsis. To characterize the specific regions of the RIP1 promoter that might be essential for its maximum activity and specificity in fruits, we made stable transgenic lines of tomato and Arabidopsis with 5'-deletion constructs. Characterization of these transgenic plants showed that the full length promoter is essential for its function. Overall, we report the identification and characterization of a ripening-induced promoter of tomato, which would be useful for the controlled manipulation of the ripening-related agronomic traits in genetic manipulation studies in future.

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

    Science.gov (United States)

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

    2010-11-01

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

  18. Brassinosteroids Are Master Regulators of Gibberellin Biosynthesis in Arabidopsis

    Science.gov (United States)

    Unterholzner, Simon J.; Rozhon, Wilfried; Papacek, Michael; Ciomas, Jennifer; Lange, Theo; Kugler, Karl G.; Mayer, Klaus F.; Sieberer, Tobias; Poppenberger, Brigitte

    2015-01-01

    Plant growth and development are highly regulated processes that are coordinated by hormones including the brassinosteroids (BRs), a group of steroids with structural similarity to steroid hormones of mammals. Although it is well understood how BRs are produced and how their signals are transduced, BR targets, which directly confer the hormone’s growth-promoting effects, have remained largely elusive. Here, we show that BRs regulate the biosynthesis of gibberellins (GAs), another class of growth-promoting hormones, in Arabidopsis thaliana. We reveal that Arabidopsis mutants deficient in BR signaling are severely impaired in the production of bioactive GA, which is correlated with defective GA biosynthetic gene expression. Expression of the key GA biosynthesis gene GA20ox1 in the BR signaling mutant bri1-301 rescues many of its developmental defects. We provide evidence that supports a model in which the BR-regulated transcription factor BES1 binds to a regulatory element in promoters of GA biosynthesis genes in a BR-induced manner to control their expression. In summary, our study underscores a role of BRs as master regulators of GA biosynthesis and shows that this function is of major relevance for the growth and development of vascular plants. PMID:26243314

  19. Functional transient genetic transformation of Arabidopsis leaves by biolistic bombardment.

    Science.gov (United States)

    Ueki, Shoko; Lacroix, Benoît; Krichevsky, Alexander; Lazarowitz, Sondra G; Citovsky, Vitaly

    2009-01-01

    Transient gene expression is an indispensable tool for studying functions of gene products. In the case of plants, transient introduction of genes by Agrobacterium infiltration is a method of choice for many species. However, this technique does not work efficiently in Arabidopsis leaf tissue, the most widely used model system for basic plant biology research. Here we present an optimized protocol for biolistic delivery of plasmid DNA into the epidermis of Arabidopsis leaves, which can be easily performed using the Bio-Rad Helios gene gun system. This protocol yields efficient and reproducible transient expression of diverse genes and is exemplified here for use in a functional assay of a transcription repressor and for the subcellular localization and cell-to-cell movement of plant viral movement protein. This protocol is suitable for studies of biological function and subcellular localization of the gene product of interest directly in planta by utilizing different types of activity-based assays. Using this procedure, the data are obtained after 2-4 d of work.

  20. Methylation of Gibberellins by Arabidopsis GAMT1 and GAMT2

    Energy Technology Data Exchange (ETDEWEB)

    Varbanova,M.; Yamaguchi, S.; Yang, Y.; McKelvey, K.; Hanada, A.; Borochov, R.; Yu, F.; Jikumaru, Y.; Ross, J.; et al

    2007-01-01

    Arabidopsis thaliana GAMT1 and GAMT2 encode enzymes that catalyze formation of the methyl esters of gibberellins (GAs). Ectopic expression of GAMT1 or GAMT2 in Arabidopsis, tobacco (Nicotiana tabacum), and petunia (Petunia hybrida) resulted in plants with GA deficiency and typical GA deficiency phenotypes, such as dwarfism and reduced fertility. GAMT1 and GAMT2 are both expressed mainly in whole siliques (including seeds), with peak transcript levels from the middle until the end of silique development. Within whole siliques, GAMT2 was previously shown to be expressed mostly in developing seeds, and we show here that GAMT1 expression is also localized mostly to seed, suggesting a role in seed development. Siliques of null single GAMT1 and GAMT2 mutants accumulated high levels of various GAs, with particularly high levels of GA1 in the double mutant. Methylated GAs were not detected in wild-type siliques, suggesting that methylation of GAs by GAMT1 and GAMT2 serves to deactivate GAs and initiate their degradation as the seeds mature. Seeds of homozygous GAMT1 and GAMT2 null mutants showed reduced inhibition of germination, compared with the wild type, when placed on plates containing the GA biosynthesis inhibitor ancymidol, with the double mutant showing the least inhibition. These results suggest that the mature mutant seeds contained higher levels of active GAs than wild-type seeds.

  1. Boosting transcription by transcription: enhancer-associated transcripts.

    Science.gov (United States)

    Darrow, Emily M; Chadwick, Brian P

    2013-12-01

    Enhancers are traditionally viewed as DNA sequences located some distance from a promoter that act in cis and in an orientation-independent fashion to increase utilization of specific promoters and thereby regulate gene expression. Much progress has been made over the last decade toward understanding how these distant elements interact with target promoters, but how transcription is enhanced remains an object of active inquiry. Recent reports convey the prevalence and diversity of enhancer transcription and transcripts and support both as key factors with mechanistically distinct, but not mutually exclusive roles in enhancer function. Decoupling the causes and effects of transcription on the local chromatin landscape and understanding the role of enhancer transcripts in the context of long-range interactions are challenges that require additional attention. In this review, we focus on the possible functions of enhancer transcription by highlighting several recent enhancer RNA papers and, within the context of other enhancer studies, speculate on the role of enhancer transcription in regulating differential gene expression.

  2. Overexpression of OsWRKY72 gene interferes in the abscisic acid signal and auxin transport pathway of Arabidopsis

    Indian Academy of Sciences (India)

    Song Yu; Chen Ligang; Zhang Liping; Yu Diqiu

    2010-09-01

    Through activating specific transcriptional programmes, plants can launch resistance mechanisms to stressful environments and acquire a new equilibrium between development and defence. To screen the rice WRKY transcription factor which functions in abiotic stress tolerance and modulates the abscisic acid (ABA) response, we generated a whole array of 35S-OsWRKY transgenic Arabidopsis. In this study, we report that 35S-OsWRKY72 transgenic Arabidopsis, whose seed germination was retarded under normal conditions, emerged more sensitive to mannitol, NaCl, ABA stresses and sugar starvation than vector plants. Meanwhile, 35S-OsWRKY72 transgenic Arabidopsis displayed early flowering, reduced apical dominance, lost high temperature-induced hypocotyl elongation response, and enhanced gravitropism response, which were similar to the auxin-related gene mutants aux1, axr1 and bud1. Further, semi-quantitative RT-PCR showed that the expression patterns of three auxin-related genes AUX1, AXR1 and BUD1 were significantly altered in rosette leaves and inflorescences of 35S-OsWRKY72 plants compared with control Arabidopsis, and two ABA-related genes ABA2 and ABI4 were induced in 35S-OsWRKY72 seedlings. In addition, northern blot analysis indicated that, in rice, OsWRKY72 was inducible by polyethylene glycol (PEG), NaCl, naphthalene acetic acid (NAA), ABA and 42°C, similar to its orthologue AtWRKY75 in Arabidopsis, implying that these two WRKY genes might be required for multiple physiological processes in their plants. Together, these results suggest that OsWRKY72 interferes in the signal cross-talk between the ABA signal and auxin transport pathway in transgenic Arabidopsis.

  3. Jasmonate is essential for insect defense in Arabidopsis.

    Science.gov (United States)

    McConn, M; Creelman, R A; Bell, E; Mullet, J E; Browse, J

    1997-05-13

    The signaling pathways that allow plants to mount defenses against chewing insects are known to be complex. To investigate the role of jasmonate in wound signaling in Arabidopsis and to test whether parallel or redundant pathways exist for insect defense, we have studied a mutant (fad3-2 fad7-2 fad8) that is deficient in the jasmonate precursor linolenic acid. Mutant plants contained negligible levels of jasmonate and showed extremely high mortality ( approximately 80%) from attack by larvae of a common saprophagous fungal gnat, Bradysia impatiens (Diptera: Sciaridae), even though neighboring wild-type plants were largely unaffected. Application of exogenous methyl jasmonate substantially protected the mutant plants and reduced mortality to approximately 12%. These experiments precisely define the role of jasmonate as being essential for the induction of biologically effective defense in this plant-insect interaction. The transcripts of three wound-responsive genes were shown not to be induced by wounding of mutant plants but the same transcripts could be induced by application of methyl jasmonate. By contrast, measurements of transcript levels for a gene encoding glutathione S-transferase demonstrated that wound induction of this gene is independent of jasmonate synthesis. These results indicate that the mutant will be a good genetic model for testing the practical effectiveness of candidate defense genes.

  4. Characterization of an activation-tagged mutant uncovers a role of GLABRA2 in anthocyanin biosynthesis in Arabidopsis.

    Science.gov (United States)

    Wang, Xiaoyu; Wang, Xianling; Hu, Qingnan; Dai, Xuemei; Tian, Hainan; Zheng, Kaijie; Wang, Xiaoping; Mao, Tonglin; Chen, Jin-Gui; Wang, Shucai

    2015-07-01

    In Arabidopsis, anthocyanin biosynthesis is controlled by a MYB-bHLH-WD40 (MBW) transcriptional activator complex. The MBW complex activates the transcription of late biosynthesis genes in the flavonoid pathway, leading to the production of anthocyanins. A similar MBW complex regulates epidermal cell fate by activating the transcription of GLABRA2 (GL2), a homeodomain transcription factor required for trichome formation in shoots and non-hair cell formation in roots. Here we provide experimental evidence to show that GL2 also plays a role in regulating anthocyanin biosynthesis in Arabidopsis. From an activation-tagged mutagenized population of Arabidopsis plants, we isolated a dominant, gain-of-function mutant with reduced anthocyanins. Molecular cloning revealed that this phenotype is caused by an elevated expression of GL2, thus the mutant was named gl2-1D. Consistent with the view that GL2 acts as a negative regulator of anthocyanin biosynthesis, gl2-1D seedlings accumulated less whereas gl2-3 seedlings accumulated more anthocyanins in response to sucrose. Gene expression analysis indicated that expression of late, but not early, biosynthesis genes in the flavonoid pathway was dramatically reduced in gl2-1D but elevated in gl2-3 mutants. Further analysis showed that expression of some MBW component genes involved in the regulation of late biosynthesis genes was reduced in gl2-1D but elevated in gl2-3 mutants, and chromatin immunoprecipitation results indicated that some MBW component genes are targets of GL2. We also showed that GL2 functions as a transcriptional repressor. Taken together, these results indicate that GL2 negatively regulates anthocyanin biosynthesis in Arabidopsis by directly repressing the expression of some MBW component genes.

  5. Dynamic light regulation of translation status in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Julia eBailey-Serres

    2012-04-01

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

  6. Jasmonate Signal Pathway in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Xiao-Yi Shan; Zhi-Long Wang; Daoxin Xie

    2007-01-01

    Jasmonates (JAs), which include jasmonic acid and its cyclopentane derivatives are synthesized from the octadecanoid pathway and widely distributed throughout the plant kingdom. JAs modulate the expression of numerous genes and mediate responses to stress, wounding, insect attack, pathogen infection, and UV damage. They also affect a variety of processes in many plant developmental processes. The JA signal pathway involves two important events: the biosynthesis of JA and the transduction of JA signal. Several important Arabidopsis mutants in jasmonate signal pathway were described in this review.

  7. BROTHER OF LUX ARRHYTHMO is a component of the Arabidopsis circadian clock.

    Science.gov (United States)

    Dai, Shunhong; Wei, Xiaoping; Pei, Liping; Thompson, Rebecca L; Liu, Yi; Heard, Jacqueline E; Ruff, Thomas G; Beachy, Roger N

    2011-03-01

    BROTHER OF LUX ARRHYTHMO (BOA) is a GARP family transcription factor in Arabidopsis thaliana and is regulated by circadian rhythms. Transgenic lines that constitutively overexpress BOA exhibit physiological and developmental changes, including delayed flowering time and increased vegetative growth under standard growing conditions. Arabidopsis circadian clock protein CIRCADIAN CLOCK ASSOCIATED1 (CCA1) binds to the evening element of the BOA promoter and negatively regulates its expression. Furthermore, the period of BOA rhythm was shortened in cca1-11, lhy-21 (for LATE ELONGATED HYPOCOTYL), and cca1-11 lhy-21 genetic backgrounds. BOA binds to the promoter of CCA1 through newly identified promoter binding sites and activates the transcription of CCA1 in vivo and in vitro. In transgenic Arabidopsis lines that overexpress BOA, the period length of CCA1 rhythm was increased and the amplitude was enhanced. Rhythmic expression of other clock genes, including LHY, GIGANTEA (GI), and TIMING OF CAB EXPRESSION1 (TOC1), was altered in transgenic lines that overexpress BOA. Rhythmic expression of BOA was also affected in mutant lines of toc1-1, gi-3, and gi-4. Results from these studies indicate that BOA is a critical component of the regulatory circuit of the circadian clock.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-04-01

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

  9. Seed dormancy release in Arabidopsis Cvi by dry after-ripening, low temperature, nitrate and light shows common quantitative patterns of gene expression directed by environment specific sensing

    NARCIS (Netherlands)

    Finch-Savage, W.E.; Cadman, C.S.C.; Toorop, P.E.; Lynn, J.R.; Hilhorst, H.W.M.

    2007-01-01

    The depth of seed dormancy can be influenced by a number of different environmental signals, but whether a common mechanism underlies this apparently similar response has yet to be investigated. Full-genome microarrays were used for a global transcript analysis of Arabidopsis thaliana Cape Verde Isl

  10. β-Glucosidase BGLU42 is a MYB72-dependent key regulator of rhizobacteria-induced systemic resistance and modulates iron deficiency responses in Arabidopsis roots

    NARCIS (Netherlands)

    Zamioudis, Christos; Hanson, Johannes; Pieterse, Corné M J

    2014-01-01

    Selected soil-borne rhizobacteria can trigger an induced systemic resistance (ISR) that is effective against a broad spectrum of pathogens. In Arabidopsis thaliana, the root-specific transcription factor MYB72 is required for the onset of ISR, but is also associated with plant survival under conditi

  11. Rhizobacterial volatiles and photosynthesis-related signals coordinate MYB72 in Arabidopsis roots during onset of induced systemic resistance and iron deficiency responses

    NARCIS (Netherlands)

    Zamioudis, C.; Korteland, J.; Van Pelt, J.A.; Van Hamersveld, M.; Dombrowski, N.; Bai, Y.; Hanson, J.; Van Verk, M.C.; Ling, H.-Q.; Schulze-Lefert, P.; Pieterse, C.M.J.

    2015-01-01

    In Arabidopsis roots, the transcription factor MYB72 plays a dual role in the onset of rhizobacteria-induced systemic resistance (ISR) and plant survival under conditions of limited iron availability. Previously, it was shown that MYB72 coordinates the expression of a gene module that promotes synth

  12. LUX ARRHYTHMO encodes a nighttime repressor of circadian gene expression in the Arabidopsis core clock.

    Science.gov (United States)

    Helfer, Anne; Nusinow, Dmitri A; Chow, Brenda Y; Gehrke, Andrew R; Bulyk, Martha L; Kay, Steve A

    2011-01-25

    Circadian clocks provide an adaptive advantage by allowing organisms to anticipate daily and seasonal environmental changes [1, 2]. Eukaryotic oscillators rely on complex hierarchical networks composed of transcriptional and posttranslational regulatory circuits [3]. In Arabidopsis, current representations of the circadian clock consist of three or four interlocked transcriptional feedback loops [3, 4]. Although molecular components contributing to different domains of these circuits have been described, how the loops are connected at the molecular level is not fully understood. Genetic screens previously identified LUX ARRHYTHMO (LUX) [5], also known as PHYTOCLOCK1 (PCL1) [6], an evening-expressed putative transcription factor essential for circadian rhythmicity. We determined the in vitro DNA-binding specificity for LUX by using universal protein binding microarrays; we then demonstrated that LUX directly regulates the expression of PSEUDO RESPONSE REGULATOR9 (PRR9), a major component of the morning transcriptional feedback circuit, through association with the newly discovered DNA binding site. We also show that LUX binds to its own promoter, defining a new negative autoregulatory feedback loop within the core clock. These novel connections between the archetypal loops of the Arabidopsis clock represent a significant advance toward defining the molecular dynamics underlying the circadian network in plants and provide the first mechanistic insight into the molecular function of the previously orphan clock factor LUX.

  13. The Clubroot Pathogen (Plasmodiophora brassicae Influences Auxin Signaling to Regulate Auxin Homeostasis in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Linda Jahn

    2013-11-01

    Full Text Available The clubroot disease, caused by the obligate biotrophic protist Plasmodiophora brassicae, affects cruciferous crops worldwide. It is characterized by root swellings as symptoms, which are dependent on the alteration of auxin and cytokinin metabolism. Here, we describe that two different classes of auxin receptors, the TIR family and the auxin binding protein 1 (ABP1 in Arabidopsis thaliana are transcriptionally upregulated upon gall formation. Mutations in the TIR family resulted in more susceptible reactions to the root pathogen. As target genes for the different pathways we have investigated the transcriptional regulation of selected transcriptional repressors (Aux/IAA and transcription factors (ARF. As the TIR pathway controls auxin homeostasis via the upregulation of some auxin conjugate synthetases (GH3, the expression of selected GH3 genes was also investigated, showing in most cases upregulation. A double gh3 mutant showed also slightly higher susceptibility to P. brassicae infection, while all tested single mutants did not show any alteration in the clubroot phenotype. As targets for the ABP1-induced cell elongation the effect of potassium channel blockers on clubroot formation was investigated. Treatment with tetraethylammonium (TEA resulted in less severe clubroot symptoms. This research provides evidence for the involvement of two auxin signaling pathways in Arabidopsis needed for the establishment of the root galls by P. brassicae.

  14. Reciprocal responses in the interaction between Arabidopsis and the cell-content-feeding chelicerate herbivore spider mite.

    Science.gov (United States)

    Zhurov, Vladimir; Navarro, Marie; Bruinsma, Kristie A; Arbona, Vicent; Santamaria, M Estrella; Cazaux, Marc; Wybouw, Nicky; Osborne, Edward J; Ens, Cherise; Rioja, Cristina; Vermeirssen, Vanessa; Rubio-Somoza, Ignacio; Krishna, Priti; Diaz, Isabel; Schmid, Markus; Gómez-Cadenas, Aurelio; Van de Peer, Yves; Grbic, Miodrag; Clark, Richard M; Van Leeuwen, Thomas; Grbic, Vojislava

    2014-01-01

    Most molecular-genetic studies of plant defense responses to arthropod herbivores have focused on insects. However, plant-feeding mites are also pests of diverse plants, and mites induce different patterns of damage to plant tissues than do well-studied insects (e.g. lepidopteran larvae or aphids). The two-spotted spider mite (Tetranychus urticae) is among the most significant mite pests in agriculture, feeding on a staggering number of plant hosts. To understand the interactions between spider mite and a plant at the molecular level, we examined reciprocal genome-wide responses of mites and its host Arabidopsis (Arabidopsis thaliana). Despite differences in feeding guilds, we found that transcriptional responses of Arabidopsis to mite herbivory resembled those observed for lepidopteran herbivores. Mutant analysis of induced plant defense pathways showed functionally that only a subset of induced programs, including jasmonic acid signaling and biosynthesis of indole glucosinolates, are central to Arabidopsis's defense to mite herbivory. On the herbivore side, indole glucosinolates dramatically increased mite mortality and development times. We identified an indole glucosinolate dose-dependent increase in the number of differentially expressed mite genes belonging to pathways associated with detoxification of xenobiotics. This demonstrates that spider mite is sensitive to Arabidopsis defenses that have also been associated with the deterrence of insect herbivores that are very distantly related to chelicerates. Our findings provide molecular insights into the nature of, and response to, herbivory for a representative of a major class of arthropod herbivores.

  15. Analysis of Arabidopsis JAZ gene expression during Pseudomonas syringae pathogenesis.

    Science.gov (United States)

    Demianski, Agnes J; Chung, Kwi Mi; Kunkel, Barbara N

    2012-01-01

    The jasmonates (JAs) comprise a family of plant hormones that regulate several developmental processes and mediate responses to various abiotic and biotic stresses, including pathogens. JA signalling is manipulated by several strains of the bacterial pathogen Pseudomonas syringae, including P. syringae strain DC3000, using the virulence factor coronatine (COR) as a mimic of jasmonyl-L-isoleucine (JA-Ile). To better understand the JA-Ile-mediated processes contributing to P. syringae disease susceptibility, it is important to investigate the regulation of JA signalling during infection. In Arabidopsis thaliana, JASMONATE ZIM-DOMAIN (JAZ) proteins are negative regulators of JA signalling. The transcription factor JASMONATE INSENSITIVE1 (JIN1/ATMYC2) has been implicated in the regulation of JAZ gene expression. To investigate the regulation of JAZ genes during P. syringae pathogenesis, we examined JAZ gene expression during infection of Arabidopsis by DC3000. We found that eight of the 12 JAZ genes are induced during infection in a COR-dependent manner. Unexpectedly, the induction of the majority of JAZ genes during infection was not dependent on JIN1, indicating that JIN1 is not the only transcription factor regulating JAZ genes. A T-DNA insertion mutant and an RNA interference line disrupted for the expression of JAZ10, one of the few JAZ genes regulated by JIN1 during infection, exhibited enhanced JA sensitivity and increased susceptibility to DC3000, with the primary effect being increased disease symptom severity. Thus, JAZ10 is a negative regulator of both JA signalling and disease symptom development.

  16. Arabidopsis PIZZA has the capacity to acylate brassinosteroids.

    Science.gov (United States)

    Schneider, Katja; Breuer, Christian; Kawamura, Ayako; Jikumaru, Yusuke; Hanada, Atsushi; Fujioka, Shozo; Ichikawa, Takanari; Kondou, Youichi; Matsui, Minami; Kamiya, Yuji; Yamaguchi, Shinjiro; Sugimoto, Keiko

    2012-01-01

    Brassinosteroids (BRs) affect a wide range of developmental processes in plants and compromised production or signalling of BRs causes severe growth defects. To identify new regulators of plant organ growth, we searched the Arabidopsis FOX (Full-length cDNA Over-eXpressor gene) collection for mutants with altered organ size and isolated two overexpression lines that display typical BR deficient dwarf phenotypes. The phenotype of these lines, caused by an overexpression of a putative acyltransferase gene PIZZA (PIZ), was partly rescued by supplying exogenous brassinolide (BL) and castasterone (CS), indicating that endogenous BR levels are rate-limiting for the growth of PIZ overexpression lines. Our transcript analysis further showed that PIZ overexpression leads to an elevated expression of genes involved in BR biosynthesis and a reduced expression of BR inactivating hydroxylases, a transcriptional response typical to low BR levels. Taking the advantage of relatively high endogenous BR accumulation in a mild bri1-301 background, we found that overexpression of PIZ results in moderately reduced levels of BL and CS and a strong reduction of typhasterol (TY) and 6-deoxocastasterone (6-deoxoCS), suggesting a role of PIZ in BR metabolism. We tested a set of potential substrates in vitro for heterologously expressed PIZ and confirmed its acyltransferase activity with BL, CS and TY. The PIZ gene is expressed in various tissues but as reported for other genes involved in BR metabolism, the loss-of-function mutants did not display obvious growth phenotypes under standard growth conditions. Together, our data suggest that PIZ can modify BRs by acylation and that these properties might help modulating endogenous BR levels in Arabidopsis.

  17. Arabidopsis PIZZA has the capacity to acylate brassinosteroids.

    Directory of Open Access Journals (Sweden)

    Katja Schneider

    Full Text Available Brassinosteroids (BRs affect a wide range of developmental processes in plants and compromised production or signalling of BRs causes severe growth defects. To identify new regulators of plant organ growth, we searched the Arabidopsis FOX (Full-length cDNA Over-eXpressor gene collection for mutants with altered organ size and isolated two overexpression lines that display typical BR deficient dwarf phenotypes. The phenotype of these lines, caused by an overexpression of a putative acyltransferase gene PIZZA (PIZ, was partly rescued by supplying exogenous brassinolide (BL and castasterone (CS, indicating that endogenous BR levels are rate-limiting for the growth of PIZ overexpression lines. Our transcript analysis further showed that PIZ overexpression leads to an elevated expression of genes involved in BR biosynthesis and a reduced expression of BR inactivating hydroxylases, a transcriptional response typical to low BR levels. Taking the advantage of relatively high endogenous BR accumulation in a mild bri1-301 background, we found that overexpression of PIZ results in moderately reduced levels of BL and CS and a strong reduction of typhasterol (TY and 6-deoxocastasterone (6-deoxoCS, suggesting a role of PIZ in BR metabolism. We tested a set of potential substrates in vitro for heterologously expressed PIZ and confirmed its acyltransferase activity with BL, CS and TY. The PIZ gene is expressed in various tissues but as reported for other genes involved in BR metabolism, the loss-of-function mutants did not display obvious growth phenotypes under standard growth conditions. Together, our data suggest that PIZ can modify BRs by acylation and that these properties might help modulating endogenous BR levels in Arabidopsis.

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

    LENUS (Irish Health Repository)

    McKeown, Peter C

    2011-08-12

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

  19. NAC Transcription Factors in Stress Responses and Senescence

    DEFF Research Database (Denmark)

    O'Shea, Charlotte

    in Arabidopsis as a prerequisite for a system-wide understanding of NAC transcription factors. This PhD thesis contributes to the work through the production and purification of NAC domain recombinant proteins. More importantly, the work presented here has created a platform for future verification of predicted......Plant-specific NAM/ATAF/CUC (NAC) transcription factors have recently received considerable attention due to their significant roles in plant development and stress signalling. This interest has resulted in a number of physiological, genetic and cell biological studies of their functions. Some...... not involve significant folding-upon-binding but fuzziness or an extended ANAC046 region. The ANAC046 regulatory domain functions as an entropic chain with a bait for interactions with for example RCD1. RCD1 interacts with transcription factors from several different families, and the large stress...

  20. Determination and inference of eukaryotic transcription factor sequence specificity.

    Science.gov (United States)

    Weirauch, Matthew T; Yang, Ally; Albu, Mihai; Cote, Atina G; Montenegro-Montero, Alejandro; Drewe, Philipp; Najafabadi, Hamed S; Lambert, Samuel A; Mann, Ishminder; Cook, Kate; Zheng, Hong; Goity, Alejandra; van Bakel, Harm; Lozano, Jean-Claude; Galli, Mary; Lewsey, Mathew G; Huang, Eryong; Mukherjee, Tuhin; Chen, Xiaoting; Reece-Hoyes, John S; Govindarajan, Sridhar; Shaulsky, Gad; Walhout, Albertha J M; Bouget, François-Yves; Ratsch, Gunnar; Larrondo, Luis F; Ecker, Joseph R; Hughes, Timothy R

    2014-09-11

    Transcription factor (TF) DNA sequence preferences direct their regulatory activity, but are currently known for only ∼1% of eukaryotic TFs. Broadly sampling DNA-binding domain (DBD) types from multiple eukaryotic clades, we determined DNA sequence preferences for >1,000 TFs encompassing 54 different DBD classes from 131 diverse eukaryotes. We find that closely related DBDs almost always have very similar DNA sequence preferences, enabling inference of motifs for ∼34% of the ∼170,000 known or predicted eukaryotic TFs. Sequences matching both measured and inferred motifs are enriched in chromatin immunoprecipitation sequencing (ChIP-seq) peaks and upstream of transcription start sites in diverse eukaryotic lineages. SNPs defining expression quantitative trait loci in Arabidopsis promoters are also enriched for predicted TF binding sites. Importantly, our motif "library" can be used to identify specific TFs whose binding may be altered by human disease risk alleles. These data present a powerful resource for mapping transcriptional networks across eukaryotes.

  1. Phytotoxicity effects and biological responses of Arabidopsis thaliana to 2,3,7,8-tetrachlorinated dibenzo-p-dioxin exposure.

    Science.gov (United States)

    Hanano, Abdulsamie; Almousally, Ibrahem; Shaban, Mouhnad

    2014-06-01

    Dioxins are persistent organic pollutants. Their bioaccumulation in the food chain makes dioxins a considerable risk for human health. The use of plants for removing toxic organic compounds, including dioxins, is a safe and efficient strategy. Herein we studied the toxicity effects and the biological responses in Arabidopsis thaliana to 2',3',7',8'-tetrachlorinated dibenzo-p-dioxin (TCDD) exposure. First, TCDD-induced toxicity was demonstrated using several parameters including, a decrease in seed germination, a loss in fresh weight with a striking decrease in chlorophyll content, but not in carotenoids, and an augmentation in the biomass of the lateral roots system, but not in the elongation of the primary root. Uptake of TCDD by Arabidopsis was confirmed. Responses to TCDD-exposure were marked by an enhanced level of hydrogen peroxide H2O2 production and a massive stimulation of anti-oxidative enzyme activities. Moreover, a significant variation in the transcript level of transcription factor genes, bHLH, MYB and AP2-EREBP was detected in Arabidopsis shoot and an up-regulation of WRKY, MYB and IAA was observed in the root. Our results illustrate the TCDD-induced toxicity effects and the biological responses of Arabidopsis to TCDD. Better understanding of the plants ability to detoxifydioxins would help to improve their use as a safe bioremediators.

  2. Reference: 572 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available et al. 2007 May. Plant J. 50(3):439-51. Although glycine-rich RNA-binding protein 2 (GRP2) has been implicated in plant re...sponses to environmental stresses, the function and importance of GRP2 in stress responses are largely unknown. Here...haliana under high-salinity, cold or osmotic stress. GRP2 affects seed germination of Arabidopsis plants under salt stre...ss, but does not influence seed germination and seedling growth of Arabidopsis plants under osmotic stre...ss. GRP2 accelerates seed germination and seedling growth in Arabidopsis plants under cold stre

  3. Reference: 446 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available rk E et al. 2006 Nov. Plant Physiol. 142(3):1004-13. Arabidopsis (Arabidopsis thaliana) QUARTET (QRT) genes are require...d for pollen separation during normal floral development. In qrt mutants, the four products of microsporogenesis re...main fused and pollen grains are released as tetrads. In Arabid...opsis, tetrad analysis in qrt mutants has been used to map all five centromeres, easily distinguish sporophy...tic from gametophytic mutations, and accurately assess crossover interference. Using a combination of forward and re

  4. Cis-regulatory element-based genome-wide identification of DREB1/CBF targets in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Huan Zhao; Weizhong Liu; Yong Hu; Xianglin Liu; Yikun He

    2008-01-01

    Microarray analysis is used to identify transcriptional targets.However,the direct targets of transcription factors cannot be distin guished from indirect ones;further,genes with low-expression levels cannot be identified by this method.In the present study,we exploi the cis-element dehydration-responsive element(DRE)that is known to be responsible for the transcription of DRE binding factor](DREB1)targets in the promoter region of all Arabidopsis genes.Putative targets whose promoters contain the elements were verified by both microarray and reverse transcription-polymerase chain reaction(RT-PCR)analysis.Five new DREB 1/CBF direct targets were identified.Compared with traditional microarray analysis,our method is convenient and cost-effective for identifying the downstream targets of transcription factors.

  5. The Function of the Early Trichomes Gene in Arabidopsis and Maize.

    Energy Technology Data Exchange (ETDEWEB)

    Scott Poethig

    2011-12-05

    Lateral organ polarity in Arabidopsis is regulated by antagonistic interactions between genes that promote either adaxial or abaxial identity, but the molecular basis of this interaction is largely unknown. We show that the adaxial regulator ASYMMETRIC LEAVES2 (AS2) is a direct target of the abaxial regulator KANADI1 (KAN1), and that KAN1 represses the transcription of AS2 in abaxial cells. Mutation of a single nucleotide in a KAN1 binding site in the AS2 promoter causes AS2 to be ectopically expressed in abaxial cells, resulting in a dominant, adaxialized phenotype. We also show that the abaxial expression of KAN1 is mediated directly or indirectly by AS2. These results demonstrate that KAN1 acts as a transcriptional repressor and that mutually repressive interactions between KAN1 and AS2 contribute to the establishment of adaxial-abaxial polarity in plants. A screen for mutations that affect the expression of a GFP reporter for KANADI2 produced mutations in two genes, CENTER CITY (CCT) and GRAND CENTRAL (GCT). Mutations in GCT and CCT delay the specification of central and peripheral identity and the globular-to-heart transition, but have little or no effect on the initial growth rate of the embryo. Mutant embryos eventually recover and undergo relatively normal patterning, albeit at an inappropriate size. GCT and CCT were identified as the Arabidopsis orthologs of MED12 and MED13--evolutionarily conserved proteins that act in association with the Mediator complex to negatively regulate transcription. The predicted function of these proteins combined with the effect of gct and cct on embryo development suggests that MED12 and MED13 regulate pattern formation during Arabidopsis embryogenesis by transiently repressing a transcriptional program that interferes with this process. Their mutant phenotype reveals the existence of a previously unknown temporal regulatory mechanism in plant embryogenesis.

  6. Auxin and ethylene induce flavonol accumulation through distinct transcriptional networks.

    Science.gov (United States)

    Lewis, Daniel R; Ramirez, Melissa V; Miller, Nathan D; Vallabhaneni, Prashanthi; Ray, W Keith; Helm, Richard F; Winkel, Brenda S J; Muday, Gloria K

    2011-05-01

    Auxin and ethylene are key regulators of plant growth and development, and thus the transcriptional networks that mediate responses to these hormones have been the subject of intense research. This study dissected the hormonal cross talk regulating the synthesis of flavonols and examined their impact on root growth and development. We analyzed the effects of auxin and an ethylene precursor on roots of wild-type and hormone-insensitive Arabidopsis (Arabidopsis thaliana) mutants at the transcript, protein, and metabolite levels at high spatial and temporal resolution. Indole-3-acetic acid (IAA) and 1-aminocyclopropane-1-carboxylic acid (ACC) differentially increased flavonol pathway transcripts and flavonol accumulation, altering the relative abundance of quercetin and kaempferol. The IAA, but not ACC, response is lost in the transport inhibitor response1 (tir1) auxin receptor mutant, while ACC responses, but not IAA responses, are lost in ethylene insensitive2 (ein2) and ethylene resistant1 (etr1) ethylene signaling mutants. A kinetic analysis identified increases in transcripts encoding the transcriptional regulators MYB12, Transparent Testa Glabra1, and Production of Anthocyanin Pigment after hormone treatments, which preceded increases in transcripts encoding flavonoid biosynthetic enzymes. In addition, myb12 mutants were insensitive to the effects of auxin and ethylene on flavonol metabolism. The equivalent phenotypes for transparent testa4 (tt4), which makes no flavonols, and tt7, which makes kaempferol but not quercetin, showed that quercetin derivatives are the inhibitors of basipetal root auxin transport, gravitropism, and elongation growth. Collectively, these experiments demonstrate that auxin and ethylene regulate flavonol biosynthesis through distinct signaling networks involving TIR1 and EIN2/ETR1, respectively, both of which converge on MYB12. This study also provides new evidence that quercetin is the flavonol that modulates basipetal auxin transport.

  7. Transcriptional control of fleshy fruit development and ripening.

    Science.gov (United States)

    Karlova, Rumyana; Chapman, Natalie; David, Karine; Angenent, Gerco C; Seymour, Graham B; de Maagd, Ruud A

    2014-08-01

    Fleshy fruits have evolved to be attractive to frugivores in order to enhance seed dispersal, and have become an indispensable part of the human diet. Here we review the recent advances in the understanding of transcriptional regulation of fleshy fruit development and ripening with a focus on tomato. While aspects of fruit development are probably conserved throughout the angiosperms, including the model plant Arabidopsis thaliana, it is shown that the likely orthologues of Arabidopsis genes have distinct functions in fleshy fruits. The model for the study of fleshy fruit development is tomato, because of the availability of single gene mutants and transgenic knock-down lines. In other species, our knowledge is often incomplete or absent. Tomato fruit size and shape are co-determined by transcription factors acting during formation of the ovary. Other transcription factors play a role in fruit chloroplast formation, and upon ripening impact quality aspects such as secondary metabolite content. In tomato, the transcription factors NON-RIPENING (NOR), COLORLESS NON-RIPENING (CNR), and RIPENING INHIBITOR (MADS-RIN) in concert with ethylene signalling regulate ripening, possibly in response to a developmental switch. Additional components include TOMATO AGAMOUS-LIKE1 (TAGL1), APETALA2a (AP2a), and FRUITFULL (FUL1 and FUL2). The links between this highly connected regulatory network and downstream effectors modulating colour, texture, and flavour are still relatively poorly understood. Intertwined with this network is post-transcriptional regulation by fruit-expressed microRNAs targeting several of these transcription factors. This important developmental process is also governed by changes in DNA methylation levels and possibly chromatin remodelling.

  8. The EDLL motif: a potent plant transcriptional activation domain from AP2/ERF transcription factors.

    Science.gov (United States)

    Tiwari, Shiv B; Belachew, Alemu; Ma, Siu Fong; Young, Melinda; Ade, Jules; Shen, Yu; Marion, Colleen M; Holtan, Hans E; Bailey, Adina; Stone, Jeffrey K; Edwards, Leslie; Wallace, Andreah D; Canales, Roger D; Adam, Luc; Ratcliffe, Oliver J; Repetti, Peter P

    2012-06-01

    In plants, the ERF/EREBP family of transcriptional regulators plays a key role in adaptation to various biotic and abiotic stresses. These proteins contain a conserved AP2 DNA-binding domain and several uncharacterized motifs. Here, we describe a short motif, termed 'EDLL', that is present in AtERF98/TDR1 and other clade members from the same AP2 sub-family. We show that the EDLL motif, which has a unique arrangement of acidic amino acids and hydrophobic leucines, functions as a strong activation domain. The motif is transferable to other proteins, and is active at both proximal and distal positions of target promoters. As such, the EDLL motif is able to partly overcome the repression conferred by the AtHB2 transcription factor, which contains an ERF-associated amphiphilic repression (EAR) motif. We further examined the activation potential of EDLL by analysis of the regulation of flowering time by NF-Y (nuclear factor Y) proteins. Genetic evidence indicates that NF-Y protein complexes potentiate the action of CONSTANS in regulation of flowering in Arabidopsis; we show that the transcriptional activation function of CONSTANS can be substituted by direct fusion of the EDLL activation motif to NF-YB subunits. The EDLL motif represents a potent plant activation domain that can be used as a tool to confer transcriptional activation potential to heterologous DNA-binding proteins.

  9. Molecular and structural analyses of a novel temperature stress-induced lipocalin from wheat and Arabidopsis.

    Science.gov (United States)

    Frenette Charron, Jean Benoit; Breton, Ghislain; Badawi, Mohamed; Sarhan, Fathey

    2002-04-24

    Two cDNAs corresponding to a novel lipocalin were identified from wheat and Arabidopsis. The two cDNAs designated Tatil for Triticum aestivum L. temperature-induced lipocalin and Attil for Arabidopsis thaliana temperature-induced lipocalin encode polypeptides of 190 and 186 amino acids respectively. Structure analyses indicated the presence of the three structurally conserved regions that characterize lipocalins. Sequence analyses revealed that this novel class of plant lipocalin shares homology with three evolutionarily related lipocalins: the mammalian apolipoprotein D (ApoD), the bacterial lipocalin and the insect Lazarillo. The comparison of the putative tertiary structures of both the human ApoD and the wheat TaTIL suggest that the two proteins differ in membrane attachment and ligand interaction. Northern analyses demonstrated that Tatil and Attil transcripts are upregulated during cold acclimation and heat-shock treatment. The putative functions of this novel class of plant lipocalins during temperature stresses are discussed.

  10. Functional interconnection of MYC2 and SPA1 in the photomorphogenic seedling development of Arabidopsis.

    Science.gov (United States)

    Gangappa, Sreeramaiah N; Prasad, V Babu Rajendra; Chattopadhyay, Sudip

    2010-11-01

    MYC2 is a basic helix-loop-helix transcription factor that cross talks with light, abscisic acid (ABA), and jasmonic acid (JA) signaling pathways. Here, we have shown that Arabidopsis (Arabidopsis thaliana) MYC2 directly binds to the G-box present in the SUPPRESSOR OF PHYTOCHROME A1 (SPA1) promoter and that it controls the expression of SPA1 in a COP1-dependent manner. Analyses of atmyc2 spa1 double mutants suggest that whereas MYC2 and SPA1 act redundantly to suppress photomorphogenic growth in the dark, they function synergistically for the suppression of photomorphogenic growth in the light. Our studies have also revealed that MYC2-mediated ABA and JA responses are further modulated by SPA1. Taken together, this study demonstrates the molecular and physiological interrelations of MYC2 and SPA1 in light, ABA, and JA signaling pathways.

  11. Structure and function of centromeric and pericentromeric heterochromatin in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Lauriane eSimon

    2015-11-01

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

  12. Phytoremediation potential of Arabidopsis with reference to acrylamide and microarray analysis of acrylamide-response genes.

    Science.gov (United States)

    Gao, Jian-Jie; Peng, Ri-He; Zhu, Bo; Wang, Bo; Wang, Li-Juan; Xu, Jing; Sun, Miao; Yao, Quan-Hong

    2015-10-01

    Acrylamide (ACR) is a widely used industrial chemical. However, it is a dangerous compound because it showed neurotoxic effects in humans and act as reproductive toxicant and carcinogen in many animal species. In the environment, acrylamide has high soil mobility and may travel via groundwater. Phytoremediation is an effective method to remove the environmental pollutants, but the mechanism of plant response to acrylamide remains unknown. With the purpose of assessing remediation potentials of plants for acrylamide, we have examined acrylamide uptake by the model plant Arabidopsis grown on contaminated substrates with high performance liquid chromatography (HPLC) analysis. The result revealed that acrylamide could be absorbed and degraded by Arabidopsis. Further microarray analysis showed that 527 transcripts were up-regulated within 2-days under acrylamide exposure condition. We have found many potential acrylamide-induced genes playing a major role in plant metabolism and phytoremediation.

  13. Involvement of C2H2 zinc finger proteins in the regulation of epidermal cell fate determination in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    An Yan; Minjie Wu; Yongqin Zhao; Aidong Zhang; Bohan Liu; John Schiefelbein; Yinbo Gan

    2014-01-01

    Cell fate determination is a basic developmental process during the growth of multicellular organisms. Trichomes and root hairs of Arabidopsis are both readily accessible structures originating from the epidermal cells of the aerial tissues and roots respectively, and they serve as excellent models for understanding the molecular mecha-nisms controlling cell fate determination and cell morphogen-esis. The regulation of trichome and root hair formation is a complex program that consists of the integration of hormonal signals with a large number of transcriptional factors, including MYB and bHLH transcriptional factors. Studies during recent years have uncovered an important role of C2H2 type zinc finger proteins in the regulation of epidermal cell fate determination. Here in this minireview we briefly summarize the involvement of C2H2 zinc finger proteins in the control of trichome and root hair formation in Arabidopsis.

  14. Programming of Plant Leaf Senescence with Temporal and Inter-Organellar Coordination of Transcriptome in Arabidopsis1[OPEN

    Science.gov (United States)

    Koo, Hee Jung; Kim, Jeongsik; Jeong, Hyobin; Yang, Jin Ok; Lee, Il Hwan; Jun, Ji Hyung; Choi, Seung Hee; Park, Su Jin; Kang, Byeongsoo; Kim, You Wang; Phee, Bong-Kwan; Kim, Jin Hee; Seo, Chaehwa; Park, Charny; Kim, Sang Cheol; Park, Seongjin; Lee, Byungwook; Lee, Sanghyuk; Hwang, Daehee; Lim, Pyung Ok

    2016-01-01

    Plant leaves, harvesting light energy and fixing CO2, are a major source of foods on the earth. Leaves undergo developmental and physiological shifts during their lifespan, ending with senescence and death. We characterized the key regulatory features of the leaf transcriptome during aging by analyzing total- and small-RNA transcriptomes throughout the lifespan of Arabidopsis (Arabidopsis thaliana) leaves at multidimensions, including age, RNA-type, and organelle. Intriguingly, senescing leaves showed more coordinated temporal changes in transcriptomes than growing leaves, with sophisticated regulatory networks comprising transcription factors and diverse small regulatory RNAs. The chloroplast transcriptome, but not the mitochondrial transcriptome, showed major changes during leaf aging, with a strongly shared expression pattern of nuclear transcripts encoding chloroplast-targeted proteins. Thus, unlike animal aging, leaf senescence proceeds with tight temporal and distinct interorganellar coordination of various transcriptomes that would be critical for the highly regulated degeneration and nutrient recycling contributing to plant fitness and productivity. PMID:26966169

  15. Arabidopsis RAV1 is down-regulated by brassinosteroid and may act as a negative regulator during plant development

    Institute of Scientific and Technical Information of China (English)

    Yu Xin HU; Yong Hong WANG; Xin Fang LIU; Jia Yang LI

    2004-01-01

    RAV1 is a novel DNA-binding protein with two distinct DNA-binding domains unique in higher plants,but its role in plant growth and development remains unknown. Using cDNA array,we found that transcription of RAV1 is downregulated by epibrassinolide (epiBL) in Arabidopsis suspension cells. RNA gel blot analysis revealed that epiBL-regulated RAV1 transcription involves neither protein phosphorylation/dephosphorylation nor newly synthesized protein,and does not require the functional BRI1,suggesting that this regulation might be through a new BR signaling pathway.Overexpressing RAV1 in Arabidopsis results in a retardation of lateral root and rosette leaf development,and the underexpression causes an earlier flowering phenotype,implying that RAV1 may function as a negative regulatory component of growth and development.

  16. Arabidopsis CDS blastp result: AK065259 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK065259 J013002J18 At5g16910.1 cellulose synthase family protein similar to gi:2827143 cellulose... synthase catalytic subunit, Arabidopsis thaliana, gi:9622886 cellulose synthase-7 from Zea mays 0.0 ...

  17. Arabidopsis CDS blastp result: AK102134 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK102134 J033085F12 At5g16910.1 cellulose synthase family protein similar to gi:2827143 cellulose... synthase catalytic subunit, Arabidopsis thaliana, gi:9622886 cellulose synthase-7 from Zea mays 0.0 ...

  18. Arabidopsis CDS blastp result: AK066835 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK066835 J013087I16 At5g16910.1 cellulose synthase family protein similar to gi:2827143 cellulose... synthase catalytic subunit, Arabidopsis thaliana, gi:9622886 cellulose synthase-7 from Zea mays 1e-171 ...

  19. Arabidopsis CDS blastp result: AK100523 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK100523 J023100P04 At5g16910.1 cellulose synthase family protein similar to gi:2827143 cellulose... synthase catalytic subunit, Arabidopsis thaliana, gi:9622886 cellulose synthase-7 from Zea mays 0.0 ...

  20. Arabidopsis CDS blastp result: AK102695 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK102695 J033103F21 At5g16910.1 cellulose synthase family protein similar to gi:2827143 cellulose... synthase catalytic subunit, Arabidopsis thaliana, gi:9622886 cellulose synthase-7 from Zea mays 0.0 ...

  1. Reference: 488 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available Inactivation of ATAB2 strongly affects Arabidopsis development and thylakoid mem...n center subunits is decreased and the association of their mRNAs with polysomes is affected. ATAB2 is a chl

  2. Reference: 212 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available identified in pea (Pisum sativum) using biochemical approaches. The Arabidopsis (...C75-IV, which we studied using a range of molecular, genetic, and biochemical techniques. Expression of atTO

  3. Reference: 480 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available activity was analyzed. Compared to all other Suc transporters, AtSUC9 had an ult...abidopsis (Arabidopsis thaliana) L. Heynh., was expressed in Xenopus (Xenopus laevis) oocytes, and transport

  4. Reference: 507 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available een them. However, little is known about the mechanisms that regulate the two pathways and the metabolic cro...ss-talk. To identify such regulatory mechanisms, we isolated and characterized the Arabidopsis T-DNA inserti

  5. Reference: 278 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available functional ERA1 gene, which encodes the beta-subunit of protein farnesyltransferase (PFT), exhibit pleiotropic effects...gnaling and meristem development. Here, we report the effects of T-DNA insertion mutations in the Arabidopsi

  6. Reference: 185 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available organisms, we suggest that AtARP4 is likely to exert its effects on plant develop...nuclear actin-related protein AtARP4 in Arabidopsis has multiple effects on plant development, including ear

  7. Arabidopsis CDS blastp result: AK069960 [KOME

    Lifescience Database Archive (English)

    Full Text Available thyltransferase 1 / caffeic acid/5-hydroxyferulic acid O-methyltransferase (OMT1) identical to O-methyltrans...T1) (Flavonol 3- O-methyltransferase 1) (Caffeic acid/5-hydroxyferulic acid O- methyltransferase) {Arabidopsis thaliana} 5e-60 ...

  8. Arabidopsis CDS blastp result: AK064768 [KOME

    Lifescience Database Archive (English)

    Full Text Available thyltransferase 1 / caffeic acid/5-hydroxyferulic acid O-methyltransferase (OMT1) identical to O-methyltrans...T1) (Flavonol 3- O-methyltransferase 1) (Caffeic acid/5-hydroxyferulic acid O- methyltransferase) {Arabidopsis thaliana} 1e-112 ...

  9. Arabidopsis CDS blastp result: AK061551 [KOME

    Lifescience Database Archive (English)

    Full Text Available ethyltransferase 1 / caffeic acid/5-hydroxyferulic acid O-methyltransferase (OMT1) identical to O-methyltran...MT1) (Flavonol 3- O-methyltransferase 1) (Caffeic acid/5-hydroxyferulic acid O- methyltransferase) {Arabidopsis thaliana} 2e-67 ...

  10. Arabidopsis CDS blastp result: AK104764 [KOME

    Lifescience Database Archive (English)

    Full Text Available ethyltransferase 1 / caffeic acid/5-hydroxyferulic acid O-methyltransferase (OMT1) identical to O-methyltran...MT1) (Flavonol 3- O-methyltransferase 1) (Caffeic acid/5-hydroxyferulic acid O- methyltransferase) {Arabidopsis thaliana} 2e-67 ...

  11. Arabidopsis CDS blastp result: AK098998 [KOME

    Lifescience Database Archive (English)

    Full Text Available thyltransferase 1 / caffeic acid/5-hydroxyferulic acid O-methyltransferase (OMT1) identical to O-methyltrans...T1) (Flavonol 3- O-methyltransferase 1) (Caffeic acid/5-hydroxyferulic acid O- methyltransferase) {Arabidopsis thaliana} 8e-57 ...

  12. Arabidopsis CDS blastp result: AK061859 [KOME

    Lifescience Database Archive (English)

    Full Text Available ethyltransferase 1 / caffeic acid/5-hydroxyferulic acid O-methyltransferase (OMT1) identical to O-methyltran...MT1) (Flavonol 3- O-methyltransferase 1) (Caffeic acid/5-hydroxyferulic acid O- methyltransferase) {Arabidopsis thaliana} 1e-100 ...

  13. Arabidopsis CDS blastp result: AK103387 [KOME

    Lifescience Database Archive (English)

    Full Text Available ntical to SC35-like splicing factor SCL28, 28 kD [Arabidopsis thaliana] GI:9843655; contains Pfam profile PF00076: RNA recognition motif. (a.k.a. RRM, RBD, or RNP domain) 2e-34 ...

  14. Reference: 564 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available 39-44 17360695 2007 Feb Proceedings of the National Academy of Sciences of the Un...tion in plants. Arabidopsis plasma membrane protein crucial for Ca2+ influx and touch sensing in roots. 9 36

  15. Reference: 796 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available ceedings of the National Academy of Sciences of the United States of America DeBolt...required for normal microtubule dynamics and organization in Arabidopsis. 46 18064-9 19004800 2008 Nov Pro

  16. Reference: 67 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available A complete knockout of AGD2 renders embryos inviable. We suggest that AGD2 synthesizes an important amino a...no acid-derived molecule important for activating defense signaling. Divergent roles in Arabidopsis thaliana

  17. Reference: 420 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available are found in various compartments in plant cells. The cytosolic and chloroplast APXs appear to play important...d development, suggesting that APX3 may not be an important antioxidant enzyme in Arabidopsis, at least unde

  18. Reference: 771 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available RCADIAN TIMEKEEPER (XCT), an Arabidopsis thaliana gene important for light regula...l elongation in xct is hyposensitive to red light but hypersensitive to blue light. Finally, XCT is important

  19. Reference: 797 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available that the level of GMPase activity regulates Arabidopsis sensitivity to NH(4)(+). Further analysis showed that defective N-glycosylati...on of proteins, unfolded protein response, and cell death in the roots are likely i

  20. Arabidopsis CDS blastp result: AK241712 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK241712 J065197H24 At4g37750.1 68417.m05344 ovule development protein aintegumenta... (ANT) identical to ovule development protein aintegumenta (ANT) (GI:1244708) ) [Arabidopsis thaliana] 6e-27 ...

  1. Arabidopsis CDS blastp result: AK242957 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242957 J090089I15 At4g37750.1 68417.m05344 ovule development protein aintegumenta... (ANT) identical to ovule development protein aintegumenta (ANT) (GI:1244708) ) [Arabidopsis thaliana] 1e-28 ...

  2. Arabidopsis CDS blastp result: AK287726 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK287726 J065138E17 At4g37750.1 68417.m05344 ovule development protein aintegumenta... (ANT) identical to ovule development protein aintegumenta (ANT) (GI:1244708) ) [Arabidopsis thaliana] 1e-88 ...

  3. Arabidopsis CDS blastp result: AK242387 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242387 J080051E14 At4g37750.1 68417.m05344 ovule development protein aintegumenta... (ANT) identical to ovule development protein aintegumenta (ANT) (GI:1244708) ) [Arabidopsis thaliana] 2e-45 ...

  4. Arabidopsis CDS blastp result: AK106306 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK106306 002-101-C10 At4g37750.1 ovule development protein aintegumenta (ANT) ident...ical to ovule development protein aintegumenta (ANT) (GI:1244708) ) [Arabidopsis thaliana] 3e-89 ...

  5. Arabidopsis CDS blastp result: AK241272 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK241272 J065132I19 At4g37750.1 68417.m05344 ovule development protein aintegumenta... (ANT) identical to ovule development protein aintegumenta (ANT) (GI:1244708) ) [Arabidopsis thaliana] 1e-88 ...

  6. Arabidopsis CDS blastp result: AK240892 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK240892 J065030K10 At4g37750.1 68417.m05344 ovule development protein aintegumenta... (ANT) identical to ovule development protein aintegumenta (ANT) (GI:1244708) ) [Arabidopsis thaliana] 5e-88 ...

  7. Arabidopsis CDS blastp result: AK109848 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK109848 002-148-F05 At4g37750.1 ovule development protein aintegumenta (ANT) ident...ical to ovule development protein aintegumenta (ANT) (GI:1244708) ) [Arabidopsis thaliana] 5e-73 ...

  8. Arabidopsis CDS blastp result: AK287673 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK287673 J065121E18 At4g37750.1 68417.m05344 ovule development protein aintegumenta... (ANT) identical to ovule development protein aintegumenta (ANT) (GI:1244708) ) [Arabidopsis thaliana] 6e-17 ...

  9. Arabidopsis CDS blastp result: AK287621 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK287621 J065066I09 At4g37750.1 68417.m05344 ovule development protein aintegumenta... (ANT) identical to ovule development protein aintegumenta (ANT) (GI:1244708) ) [Arabidopsis thaliana] 5e-85 ...

  10. Reference: 142 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available te S-glucosyltransferase, UGT74B1, to determine its role in the Arabidopsis glucosinolate pathway. Biochem...ical analyses demonstrate that recombinant UGT74B1 specifically glucosylates the th

  11. Reference: 522 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available tol phosphate (InsP) and phosphoinositide phosphate (PtdInsP) substrates. Arabidopsis thaliana has 15 genes encoding 5PTases. Biochem...ical analyses of a subgroup of 5PTase enzymes suggest th

  12. Reference: 459 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available plants. These results suggest an additive contribution of AMT1;1 and AMT1;3 to the overall ammonium uptake ...capacity in Arabidopsis roots under nitrogen-deficiency conditions. Additive contribution

  13. Arabidopsis CDS blastp result: AK288065 [KOME

    Lifescience Database Archive (English)

    Full Text Available al to sulfate tansporter Sultr1;3 [Arabidopsis thaliana] GI:10716805; contains Pfam profile PF00916: Sulfate... transporter family; contains Pfam profile PF01740: STAS domain; contains TIGRfam profile TIGR00815: sulfate permease 1e-145 ...

  14. Reference: 645 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available rter AtDUR3 in nitrogen nutrition in Arabidopsis. In transgenic lines expressing ... impaired growth on urea as a sole nitrogen source were used to investigate a role of the H+/urea co-transpo

  15. The fifth international conference on Arabidopsis research

    Energy Technology Data Exchange (ETDEWEB)

    Hangarter, R.; Scholl, R.; Davis, K.; Feldmann, K.

    1993-12-31

    This volume contains abstracts of oral and poster presentations made in conjunction with the Fifth International Conference on Arabidopsis Research held August 19--22, 1993 at the Ohio State University, Columbus, Ohio.

  16. Reference: 711 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available of the RLK signaling pathway, which also mediates adaptation to Na(+) stress. RLK pathway components, known... The Arabidopsis kinase-associated protein phosphatase regulates adaptation to Na+ stress. 2 612-22 18162596

  17. Reference: 734 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available umi et al. 2008 Apr. Development 135(7):1335-45. CAPRICE (CPC) encodes a small protein with an R3 MYB motif ...doreduplication. Arabidopsis CAPRICE-LIKE MYB 3 (CPL3) controls endoreduplication and flowering development

  18. Arabidopsis CDS blastp result: AK101526 [KOME

    Lifescience Database Archive (English)

    Full Text Available ucosaminyltransferase, putative similar to N-acetylglucosaminyltransferase I from Arabidopsis thaliana [gi:5139335]; contains AT-AC non-consensus splice sites at intron 13 1e-179 ...

  19. Reference: 733 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available role in this transition. Specifically, two autonomous factors in the Arabidopsis...tes FCA alternative polyadenylation and promotes flowering as a novel factor in the autonomous pathway. Firs

  20. Reference: 343 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available the characterization of a T-DNA insertion mutant of the Arabidopsis CAP-C gene. Analysis of the progeny of selfe...matin was observed between segregating mitotic chromosomes in pollen produced by selfed heterozygotes. Addit

  1. Arabidopsis CDS blastp result: AK241281 [KOME

    Lifescience Database Archive (English)

    Full Text Available 2 protein) [Arabidopsis thaliana]; a false single bp exon was added to circumvent a single basepair insertion in the genomic sequence, supported by cDNA/genome alignment. 3e-19 ...

  2. Arabidopsis CDS blastp result: AK241243 [KOME

    Lifescience Database Archive (English)

    Full Text Available 2 protein) [Arabidopsis thaliana]; a false single bp exon was added to circumvent a single basepair insertion in the genomic sequence, supported by cDNA/genome alignment. 6e-11 ...

  3. Arabidopsis CDS blastp result: AK243188 [KOME

    Lifescience Database Archive (English)

    Full Text Available 2 protein) [Arabidopsis thaliana]; a false single bp exon was added to circumvent a single basepair insertion in the genomic sequence, supported by cDNA/genome alignment. 8e-23 ...

  4. Arabidopsis CDS blastp result: AK242986 [KOME

    Lifescience Database Archive (English)

    Full Text Available 2 protein) [Arabidopsis thaliana]; a false single bp exon was added to circumvent a single basepair insertion in the genomic sequence, supported by cDNA/genome alignment. 1e-17 ...

  5. Reference: 30 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available ponse to various biotic and abiotic stresses. However the physiological role of t...his pathway remains obscure. To elucidate its role in plants, we analyzed Arabidopsis T-DNA knockout mutants

  6. Arabidopsis CDS blastp result: AK062082 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK062082 001-044-F11 At3g59970.3 methylenetetrahydrofolate reductase 1 (MTHFR1) ide...ntical to methylenetetrahydrofolate reductase MTHFR1 [Arabidopsis thaliana] GI:5911425 4e-81 ...

  7. Reference: 783 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available sis ACBP6 was confirmed by analyses of transgenic Arabidopsis expressing autofluorescence-tagged ACBP6 and w... mRNA encoding phospholipase Ddelta. Lipid profiling analyses of rosettes from co

  8. Reference: 789 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available ylakoid membranes. Microarray analysis of the chl27-t mutant showed repression of numerous nuclear genes involved in photosynthesis...d CHL27 proteins. Role of Arabidopsis CHL27 protein for photosynthesis, chloroplast development and gene exp

  9. Reference: 352 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available em II and has a specific function distinct from 2-Cys peroxiredoxin in protecting photosynthesis. Its absenc...f Arabidopsis thaliana is attached to the thylakoids and functions in context of photosynthesis

  10. Reference: 21 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available ication of a number of mutant lines with altered Chl fluorescence characteristics. Analysis of photosynthesis...cation of mutants of Arabidopsis defective in acclimation of photosynthesis to th

  11. Reference: 413 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available ollination and fertilization, and, in the absence of fertilization, flowers senesce. In the Arabidopsis thal...ARF8 acts as an inhibitor to stop further carpel development in the absence of fertilization and the generat

  12. Reference: 405 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available as previously thought. These mutants will prove to be valuable resources for understanding laccase functions in vivo. Mutant identifi...cation and characterization of the laccase gene family in Arabidopsis. 11 2563-9 16

  13. Reference: 263 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available idopsis leaves GLB1 expression and PII protein levels were not significantly affected by either the day/nigh...bolism. Physiological characterisation of Arabidopsis mutants affected in the expression of the putative reg

  14. Reference: 160 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available excessive accumulation of these toxic compounds impairs cell death containment and counteracts the effect...iveness of the plant defenses to restrict pathogen infection. Arabidopsis SHMT1, a

  15. Arabidopsis CDS blastp result: AK242550 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK242550 J080319D10 At2g35630.1 68415.m04369 microtubule organization 1 protein (MO...R1) identical to microtubule organization 1 protein GI:14317953 from [Arabidopsis thaliana] 5e-44 ...

  16. Reference: 301 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available n phosphatidylinositol metabolism and is encoded by an At5PTase gene family in Arabidopsis thaliana. A previous study...ntracellular calcium levels. In this study, we provide evidence that At5PTase13 m

  17. Reference: 724 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available is required in the roots during early signaling steps of rhizobacteria-mediated ...ISR. MYB72 is required in early signaling steps of rhizobacteria-induced systemic resistance in Arabidopsis.

  18. Reference: 289 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available f flavonoids in Arabidopsis seed coat. 11 2966-80 16243908 2005 Nov The Plant cell Caboche Michel|Debeaujon Isabelle|Kerhoas Lucien|Lepiniec Loïc|Pourcel Lucille|Routaboul Jean-Marc

  19. Reference: 684 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available cellular proliferation and expansion at nanomolar concentrations. PSY1 is widely expressed in various Arabi...ulfated glycopeptide involved in cellular proliferation and expansion in Arabidopsis. 46 18333-8 17989228 20

  20. Reference: 147 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available the region-specific control of trichome development of Arabidopsis. 3 389-98 15604688 2004 May Plant molecular biology Hulskamp Mart...in|Kirik Victor|Schiefelbein John|Simon Marissa|Wester Katja

  1. Arabidopsis CDS blastp result: AK241043 [KOME

    Lifescience Database Archive (English)

    Full Text Available upted by a stop codon, creating non-consensus donor and acceptor splice sites. 2e-41 ... ...tical to SP|P92997 Germin-like protein subfamily 1 member 13 precursor {Arabidopsis thaliana}; exon 2 interr

  2. Arabidopsis CDS blastp result: AK243135 [KOME

    Lifescience Database Archive (English)

    Full Text Available upted by a stop codon, creating non-consensus donor and acceptor splice sites. 7e-43 ... ...tical to SP|P92997 Germin-like protein subfamily 1 member 13 precursor {Arabidopsis thaliana}; exon 2 interr

  3. Reference: 798 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available iption factors, control the delicately tuned reorientation and timing of cell div...EZ and SOMBRERO control the orientation of cell division plane in Arabidopsis root stem cells. 6 913-22 1908

  4. Activation of the Arabidopsis B class homeotic genes by APETALA1.

    Science.gov (United States)

    Ng, M; Yanofsky, M F

    2001-04-01

    Proper development of petals and stamens in Arabidopsis flowers requires the activities of APETALA3 (AP3) and PISTILLATA (PI), whose transcripts can be detected in the petal and stamen primordia. Localized expression of AP3 and PI requires the activities of at least three genes: APETALA1 (AP1), LEAFY (LFY), and UNUSUAL FLORAL ORGANS (UFO). It has been proposed that UFO provides spatial cues and that LFY specifies competence for AP3 and PI expression in the developing flower. To understand the epistatic relationship among AP1, LFY, and UFO in regulating AP3 and PI expression, we generated two versions of AP1 that have strong transcriptional activation potential. Genetic and molecular analyses of transgenic plants expressing these activated AP1 proteins show that the endogenous AP1 protein acts largely as a transcriptional activator in vivo and that AP1 specifies petals by regulating the spatial domains of AP3 and PI expression through UFO.

  5. Arabidopsis CDS blastp result: AK071710 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK071710 J023110L07 At4g14030.1 selenium-binding protein, putative contains Pfam profile PF05694: 56kDa sele...nium binding protein (SBP56); identical to Putative selenium-binding protein (Swiss...-Prot:O23264) [Arabidopsis thaliana]; similar to selenium binding protein (GI:15485232) [Arabidopsis thalian...a]; identical to cDNA from partial mRNA for selenium binding protein (sbp gene) GI:15485231 1e-162 ...

  6. Reference: 221 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available ell cycle. In addition, RAD51 is required for meiosis and its Arabidopsis (Arabidopsis thaliana) ortholog is important... cell cultures, the RAD51 paralog RAD51C is also important for mitotic homologous...ortant for recombination and DNA repair in the mitotic c...chromosome (homolog) pairing, synapsis, and recombination. The budding yeast (Saccharomyces cerevisiae) RAD51 gene is known to be imp

  7. Reference: 598 [Arabidopsis Phenome Database[Archive

    Lifescience Database Archive (English)

    Full Text Available omoter is markedly reduced in the cdkc;2 and cyct1;5 mutants, indicating that the kinase complexes are important... flowering. These results establish Arabidopsis CDKC kinase complexes as important...T1;4 and CYCT1;5, play important roles in infection with Cauliflower mosaic virus...hat Arabidopsis thaliana CDK9-like proteins, CDKC;1 and CDKC;2, and their interacting cyclin T partners, CYC

  8. Integration of hormonal signaling networks and mobile microRNAs is required for vascular patterning in Arabidopsis roots

    OpenAIRE

    Muraro, Daniele; Mellor, Nathan; Pound, Michael P.; Help, Hanna; Lucas, Mikael; Chopard, Jerome; Byrne, Helen M.; GODIN, CHRISTOPHE; Hodgman, T. Charlie; King, John R.; Pridmore, Tony P.; Helariutta, Ykä; Bennett, Malcolm J; Bishopp, Anthony

    2014-01-01

    International audience; As multicellular organisms grow, positional information is continually needed to regulate the pattern in which cells are arranged. In the Arabidopsis root, most cell types are organized in a radially symmetric pattern; however, a symmetry-breaking event generates bisymmetric auxin and cytokinin signaling domains in the stele. Bidirectional cross-talk between the stele and the surrounding tissues involving a mobile transcription factor, SHORT ROOT (SHR), and mobile micr...

  9. [Cloning and functional analysis of Phyllostachys edulis MYB transcription factor PeMYB2].

    Science.gov (United States)

    Xiao, Dong-Chang; Zhang, Zhi-Jun; Xu, Ying-Wu; Yang, Li; Zhang, Feng-Xue; Wang, Chao-Li

    2013-10-01

    MYB-type transcription factor is one of the largest families in plants, which plays important roles in accepting stress signals from environment and regulating the expression of stress-tolerant genes. In this paper, using homologous cloning and RACE technology, a MYB-type transcription factor, designated PeMYB2, was cloned from Phyllostachys edulis. The results of bioinformatics showed that PeMYB2 is a typical R2R3-MYB. It contained two tandem repeats in its N-terminus, and a membrane protein DUF3651 in its C-terminus. In addition, phylogenetic analysis indicated that PeMYB2 shared the highest homology with 85.98% to OsMYB18 protein from Oryza sativa spp. Japonica. In addition, a yeast one-hybrid assay showed that PeMYB2 could activate the expression of downstream genes. After PeMYB2 was transformed into Arabidopsis thaliana, seven PeMYB2 transgenic Arabidopsis lines were obtained. Phenotypic analysis of the transgenic and wild-type Arabidopsis showed that over-expression of PeMYB2 caused delayed flower or dwarfism in transgenic Arabidopsis. Under the abiotic stress conditions, such as salt and cold stresses, the over-expression of PeMYB2 in Arabidopsis had higher survival rate than the wild-type Arabidopsis. Expression analysis of saline stress response marker genes in the transgenic and wild-type plants under the salt stress condition showed that PeMYB2 regulated the expression of NXH1, SOS1, RD29A, and COR15A. As the result, PeMYB2 might play an important role in various responses to abiotic stresses in P. edulis.

  10. The Arabidopsis thaliana homeobox gene ATHB12 is involved in symptom development caused by geminivirus infection.

    Directory of Open Access Journals (Sweden)

    Jungan Park

    Full Text Available BACKGROUND: Geminiviruses are single-stranded DNA viruses that infect a number of monocotyledonous and dicotyledonous plants. Arabidopsis is susceptible to infection with the Curtovirus, Beet severe curly top virus (BSCTV. Infection of Arabidopsis with BSCTV causes severe symptoms characterized by stunting, leaf curling, and the development of abnormal inflorescence and root structures. BSCTV-induced symptom development requires the virus-encoded C4 protein which is thought to interact with specific plant-host proteins and disrupt signaling pathways important for controlling cell division and development. Very little is known about the specific plant regulatory factors that participate in BSCTV-induced symptom development. This study was conducted to identify specific transcription factors that are induced by BSCTV infection. METHODOLOGY/PRINCIPAL FINDINGS: Arabidopsis plants were inoculated with BSCTV and the induction of specific transcription factors was monitored using quantitative real-time polymerase chain reaction assays. We found that the ATHB12 and ATHB7 genes, members of the homeodomain-leucine zipper family of transcription factors previously shown to be induced by abscisic acid and water stress, are induced in symptomatic tissues of Arabidopsis inoculated with BSCTV. ATHB12 expression is correlated with an array of morphological abnormalities including leaf curling, stunting, and callus-like structures in infected Arabidopsis. Inoculation of plants with a BSCTV mutant with a defective c4 gene failed to induce ATHB12. Transgenic plants expressing the BSCTV C4 gene exhibited increased ATHB12 expression whereas BSCTV-infected ATHB12 knock-down plants developed milder symptoms and had lower ATHB12 expression compared to the wild-type plants. Reporter gene studies demonstrated that the ATHB12 promoter was responsive to BSCTV infection and the highest expression levels were observed in symptomatic tissues where cell cycle genes also were

  11. SUPPRESSOR OF APICAL DOMINANCE1 of Sporisorium reilianum Modulates Inflorescence Branching Architecture in Maize and Arabidopsis1[OPEN

    Science.gov (United States)

    Ghareeb, Hassan; Löfke, Christian; Teichmann, Thomas; Schirawski, Jan

    2015-01-01

    The biotrophic fungus Sporisorium reilianum causes head smut of maize (Zea mays) after systemic plant colonization. Symptoms include the formation of multiple female inflorescences at subapical nodes of the stalk because of loss of apical dominance. By deletion analysis of cluster 19-1, the largest genomic divergence cluster in S. reilianum, we identified a secreted fungal effector responsible for S. reilianum-induced loss of apical dominance, which we named SUPPRESSOR OF APICAL DOMINANCE1 (SAD1). SAD1 transcript levels were highly up-regulated during biotrophic fungal growth in all infected plant tissues. SAD1-green fluorescent protein fusion proteins expressed by recombinant S. reilianum localized to the extracellular hyphal space. Transgenic Arabidopsis (Arabidopsis thaliana)-expressing green fluorescent protein-SAD1 displayed an increased number of secondary rosette-leaf branches. This suggests that SAD1 manipulates inflorescence branching architecture in maize and Arabidopsis through a conserved pathway. Using a yeast (Saccharomyces cerevisiae) two-hybrid library of S. reilianum-infected maize tissues, we identified potential plant interaction partners that had a predicted function in ubiquitination, signaling, and nuclear processes. Presence of SAD1 led to an increase of the transcript levels of the auxin transporter PIN-FORMED1 in the root and a reduction of the branching regulator TEOSINTE BRANCHED1 in the stalk. This indicates a role of SAD1 in regulation of apical dominance by modulation of branching through increasing transcript levels of the auxin transporter PIN1 and derepression of bud outgrowth. PMID:26511912

  12. The SLO1 PPR protein is required for RNA editing at multiple sites with similar upstream sequences in Arabidopsis mitochondria.

    Science.gov (United States)

    Sung, Tzu-Ying; Tseng, Ching-Chih; Hsieh, Ming-Hsiun

    2010-08-01

    In Arabidopsis, RNA editing changes more than 500 cytidines to uridines in mitochondrial transcripts. The editing enzyme and co-factors involved in these processes are largely unknown. We have identified a nuclear gene SLOW GROWTH1 (SLO1) encoding an E motif-containing pentatricopeptide repeat protein that is required for RNA editing of nad4 and nad9 in Arabidopsis mitochondria. The SLO1 protein is localized to the mitochondrion, and its absence gives rise to small plants with slow growth and delayed development. A survey of approximately 500 mitochondrial RNA editing sites in Arabidopsis reveals that the editing of two sites, nad4-449 and nad9-328, is abolished in the slo1 mutants. Sequence comparison in the upstream (from -1 to -15 bp) of nad4-449 and nad9-328 editing sites shows that nine of the 15 nucleotides are identical. In addition to RNA editing, we used RNA gel blot analysis to compare the abundance and banding patterns of mitochondrial transcripts between the wild type and slo1 mutants. Of the 79 genes and open reading frames examined, steady-state levels of 56 mitochondrial transcripts are increased in the slo1 mutants. These results suggest that the SLO1 protein may indirectly regulate plant growth and development via affecting mitochondrial RNA editing and gene expression.

  13. Transcription regulation by CHD proteins to control plant development

    Directory of Open Access Journals (Sweden)

    Yongfeng eHu

    2014-05-01

    Full Text Available CHD (Chromodomain-Helicase-DNA binding proteins have been characterized in various species as important transcription regulators by their chromatin remodeling activity. However, in plant the function of these proteins has hardly been analyzed before except that Arabidopsis PICKLE and rice CHR729 are identified to play critical roles in the regulation of series of genes involved in developmental or stress responding process. In this review we focus on how plant CHD proteins regulate gene expression and the role of these proteins in controlling plant development and stress response.

  14. The Transcriptomic Response of Arabidopsis thaliana to Zinc Oxide: A Comparison of the Impact of Nanoparticle, Bulk, and Ionic Zinc

    OpenAIRE

    Landa, P.; Přerostová, S. (Sylva); Petrová, Š. (Šárka); V. Knirsch; Vaňková, R. (Radomíra); Vaněk, T. (Tomáš)

    2015-01-01

    The impact of nanosize was evaluated by comparing of the transcriptomic response of Arabidopsis thaliana roots to ZnO nanopartides (nZnO), bulk ZnO, and ionic Zn2+. Microarray analyses revealed 416 up- and 961 down-regulated transcripts (expression difference >2-fold, p [FDR] < 0.01) after a seven-day treatment with nZnO (average particle size 20 nm, concentration 4 mg L-1). Exposure to bulk ZnO resulted in 816 up- and 2179 down-regulated transcripts. The most dramatic changes (1711 transcrip...

  15. The role of the SCRAMBLED receptor-like kinase in patterning the Arabidopsis root epidermis.

    Science.gov (United States)

    Kwak, Su-Hwan; Schiefelbein, John

    2007-02-01

    Cell-type patterning in the Arabidopsis root epidermis is achieved by a network of transcription factors and influenced by a position-dependent mechanism. The SCRAMBLED receptor-like kinase is required for the normal pattern to arise, but its precise role is not understood. Here we describe genetic and molecular studies to define the spatial and temporal role of SCM in epidermal patterning and its relationship to the transcriptional network. Our results suggest that SCM helps unspecified epidermal cells interpret their position in relation to the underlying cortical cells and establish distinct cell identities. Furthermore, SCM loss-of-function and overexpression analyses suggest that SCM influences cell fate through its negative transcriptional regulation of the WEREWOLF MYB gene in epidermal cells at the H position. We also find that SCM function is specifically required for patterning the post-embryonic root epidermis and not for the analogous epidermal cell-type patterning during embryogenesis or hypocotyl development. In addition, we show that two closely related SCM-like genes in Arabidopsis (SRF1 and SRF3) are not required alone or together with SCM for proper epidermal patterning. These findings help define the developmental and mechanistic role of SCM and suggest a new model for its action in root epidermal cell patterning.

  16. Autophagy contributes to regulation of the hypoxia response during submergence in Arabidopsis thaliana.

    Science.gov (United States)

    Chen, Liang; Liao, Bin; Qi, Hua; Xie, Li-Juan; Huang, Li; Tan, Wei-Juan; Zhai, Ning; Yuan, Li-Bing; Zhou, Ying; Yu, Lu-Jun; Chen, Qin-Fang; Shu, Wensheng; Xiao, Shi

    2015-01-01

    Autophagy involves massive degradation of intracellular components and functions as a conserved system that helps cells to adapt to adverse conditions. In mammals, hypoxia rapidly stimulates autophagy as a cell survival response. Here, we examine the function of autophagy in the regulation of the plant response to submergence, an abiotic stress that leads to hypoxia and anaerobic respiration in plant cells. In Arabidopsis thaliana, submergence induces the transcription of autophagy-related (ATG) genes and the formation of autophagosomes. Consistent with this, the autophagy-defective (atg) mutants are hypersensitive to submergence stress and treatment with ethanol, the end product of anaerobic respiration. Upon submergence, the atg mutants have increased levels of transcripts of anaerobic respiration genes (alcohol dehydrogenase 1, ADH1 and pyruvate decarboxylase 1, PDC1), but reduced levels of transcripts of other hypoxia- and ethylene-responsive genes. Both submergence and ethanol treatments induce the accumulation of reactive oxygen species (ROS) in the rosettes of atg mutants more than in the wild type. Moreover, the production of ROS by the nicotinamide adenine dinucleotide phosphate (NADPH) oxidases is necessary for plant tolerance to submergence and ethanol, submergence-induced expression of ADH1 and PDC1, and activation of autophagy. The submergence- and ethanol-sensitive phenotypes in the atg mutants depend on a complete salicylic acid (SA) signaling pathway. Together, our findings demonstrate that submergence-induced autophagy functions in the hypoxia response in Arabidopsis by modulating SA-mediated cellular homeostasis.

  17. Characterization of Putative cis-Regulatory Elements in Genes Preferentially Expressed in Arabidopsis Male Meiocytes

    Directory of Open Access Journals (Sweden)

    Junhua Li

    2014-01-01

    Full Text Available Meiosis is essential for plant reproduction because it is the process during which homologous chromosome pairing, synapsis, and meiotic recombination occur. The meiotic transcriptome is difficult to investigate because of the size of meiocytes and the confines of anther lobes. The recent development of isolation techniques has enabled the characterization of transcriptional profiles in male meiocytes of Arabidopsis. Gene expression in male meiocytes shows unique features. The direct interaction of transcription factors (TFs with DNA regulatory sequences forms the basis for the specificity of transcriptional regulation. Here, we identified putative cis-regulatory elements (CREs associated with male meiocyte-expressed genes using in silico tools. The upstream regions (1 kb of the top 50 genes preferentially expressed in Arabidopsis meiocytes possessed conserved motifs. These motifs are putative binding sites of TFs, some of which share common functions, such as roles in cell division. In combination with cell-type-specific analysis, our findings could be a substantial aid for the identification and experimental verification of the protein-DNA interactions for the specific TFs that drive gene expression in meiocytes.

  18. The nodule inception-like protein 7 modulates nitrate sensing and metabolism in Arabidopsis.

    Science.gov (United States)

    Castaings, Loren; Camargo, Antonio; Pocholle, Delphine; Gaudon, Virginie; Texier, Yves; Boutet-Mercey, Stéphanie; Taconnat, Ludivine; Renou, Jean-Pierre; Daniel-Vedele, Françoise; Fernandez, Emilio; Meyer, Christian; Krapp, Anne

    2009-02-01

    Nitrate is an essential nutrient, and is involved in many adaptive responses of plants, such as localized proliferation of roots, flowering or stomatal movements. How such nitrate-specific mechanisms are regulated at the molecular level is poorly understood. Although the Arabidopsis ANR1 transcription factor appears to control stimulation of lateral root elongation in response to nitrate, no regulators of nitrate assimilation have so far been identified in higher plants. Legume-specific symbiotic nitrogen fixation is under the control of the putative transcription factor, NIN, in Lotus japonicus. Recently, the algal homologue NIT2 was found to regulate nitrate assimilation. Here we report that Arabidopsis thaliana NIN-like protein 7 (NLP7) knockout mutants constitutively show several features of nitrogen-starved plants, and that they are tolerant to drought stress. We show that nlp7 mutants are impaired in transduction of the nitrate signal, and that the NLP7 expression pattern is consistent with a function of NLP7 in the sensing of nitrogen. Translational fusions with GFP showed a nuclear localization for the NLP7 putative transcription factor. We propose NLP7 as an important element of the nitrate signal transduction pathway and as a new regulatory protein specific for nitrogen assimilation in non-nodulating plants.

  19. An Arabidopsis FAD pyrophosphohydrolase, AtNUDX23, is involved in flavin homeostasis.

    Science.gov (United States)

    Maruta, Takanori; Yoshimoto, Tadashi; Ito, Daisuke; Ogawa, Takahisa; Tamoi, Masahiro; Yoshimura, Kazuya; Shigeoka, Shigeru

    2012-06-01

    Although flavins, riboflavin (RF), FMN and FAD, are essential for primary and secondary metabolism in plants, the metabolic regulation of flavins is still largely unknown. Recently, we found that an Arabidopsis Nudix hydrolase, AtNUDX23, has FAD pyrophosphohydrolase activity and is distributed in plastids. Levels of RF and FAD but not FMN in Arabidopsis leaves significantly increased under continuous light and decreased in the dark. The transcript levels of AtNUDX23 as well as genes involved in flavin metabolism (AtFADS, AtRibF1, AtRibF2, AtFMN/FHy, LS and AtRibA) significantly increased under continuous light. The pyrophosphohydrolase activity toward FAD was enhanced in AtNUDX23-overexpressing (OX-NUDX23) plants and reduced in AtNUDX23-suppressed (KD-nudx23) plants, compared with the control plants. Interestingly intracellular levels of RF, FMN and FAD significantly decreased in not only OX-NUDX23 but also KD-nudx23 plants. The transcript levels of the flavin metabolic genes also decreased in both plants. Similarly, the increase in intracellular levels on treatment with flavins caused a reduction in the transcript levels of genes involved in flavin metabolism. These results suggest that negative feedback regulation of the metabolism of flavins through the hydrolysis of FAD by AtNUDX23 in plastids is involved in flavin homeostasis in plant cells.

  20. PlnTFDB: an integrative plant transcription factor database

    Directory of Open Access Journals (Sweden)

    Ruzicic Slobodan

    2007-02-01

    Full Text Available Abstract Background Transcription factors (TFs are key regulatory proteins that enhance or repress the transcriptional rate of their target genes by binding to specific promoter regions (i.e. cis-acting elements upon activation or de-activation of upstream signaling cascades. TFs thus constitute master control elements of dynamic transcriptional networks. TFs have fundamental roles in almost all biological processes (development, growth and response to environmental factors and it is assumed that they play immensely important functions in the evolution of species. In plants, TFs have been employed to manipulate various types of metabolic, developmental and stress response pathways. Cross-species comparison and identification of regulatory modules and hence TFs is thought to become increasingly important for the rational design of new plant biomass. Up to now, however, no computational repository is available that provides access to the largely complete sets of transcription factors of sequenced plant genomes. Description PlnTFDB is an integrative plant transcription factor database that provides a web interface to access large (close to complete sets of transcription factors of several plant species, currently encompassing Arabidopsis thaliana (thale cress, Populus trichocarpa (poplar, Oryza sativa (rice, Chlamydomonas reinhardtii and Ostreococcus tauri. It also provides an access point to its daughter databases of a species-centered representation of transcription factors (OstreoTFDB, ChlamyTFDB, ArabTFDB, PoplarTFDB and RiceTFDB. Information including protein sequences, coding regions, genomic sequences, expressed sequence tags (ESTs, domain architecture and scientific literature is provided for each family. Conclusion We have created lists of putatively complete sets of transcription factors and other transcriptional regulators for five plant genomes. They are publicly available through http://plntfdb.bio.uni-potsdam.de. Further data will be