The Plant Journal (PLANT J)

Publications in this journal

• Article: An upstream regulator of the 26S proteasome modulates organ size in Arabidopsis thaliana

  Hung M. Nguyen, Jos H. M. Schippers, Oscar Goni Ramos, Mathias P. Christoph, Hakan Dortay, Renier A.L. van der Hoorn, Bernd Mueller-Roeber
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  ABSTRACT: In both, animal and plant kingdoms body size is a fundamental but still poorly understood attribute of biological systems. Here we report that the Arabidopsis NAC transcription factor RPX (REGULATOR OF PROTEASOME EXPRESSION) controls leaf size by positively modulating proteasome activity. We further show that the cis-element recognized by RPX is evolutionary conserved between higher plant species. Upon overexpression of RPX, plants exhibit reduced growth which can be reversed by low concentration of the pharmacological proteasome inhibitor MG132. These data suggest that the rate of protein turn-over during growth is a critical parameter for setting final organ size.
  The Plant Journal 02/2013;
• Article: Characterization of the extracellular c-glutamyl transpeptidases, GGT1 and GGT2, in Arabidopsis

  Naoko Ohkama-Ohtsu, Safaa Radwan, Annita Peterson, Ping Zhao, Abdel Fattah Badr, Chengbin Xiang2 and David J. Oliver
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  ABSTRACT: c-Glutamyl transpeptidase (GGT) is the only enzyme known that can cleave the c-peptide bond between glutamate and cysteine in glutathione, and is therefore a key step in glutathione degradation. There are three functional GGT genes in Arabidopsis, two of which are considered here. GGT1 and GGT2 are apoplastic, associated with the plasma membrane and/or cell wall. RNA blots and analysis of enzyme activity in knockout mutants suggest that GGT1 is expressed most strongly in leaves but is found throughout the plant. A GGT1::GUS fusion construct showed expression only in vascular tissue, specifically the phloem of the mid-rib and minor veins of leaves, roots and flowers. This localization was confirmed in leaves by laser microdissection. GGT2 expression is limited to embryo, endosperm, outer integument, and a small portion of the funiculus in developing siliques. The ggt2 mutants had no detectable phenotype, while the ggt1 knockouts were smaller and flowered sooner than wild-type. In ggt1 plants, the cotyledons and older leaves yellowed early, and GSSG, the oxidized form of glutathione, accumulated in the apoplastic space. These observations suggest that GGT1 is important in preventing oxidative stress by metabolizing extracellular GSSG, while GGT2 might be important in transporting glutathione into developing seeds.
  The Plant Journal 02/2013;
• Article: Ubiquitin protein ligase 3 mediates the proteasomal degradation of GLABROUS 3 and ENHANCER OF GLABROUS 3, regulators of trichome development and flavonoid biosynthesis in Arabidopsis

  Barunava Patra, Sitakanta Pattanaik and Ling Yuan
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  ABSTRACT: Ubiquitin/26S proteasome (UPS)-dependent proteolysis of a variety of cellular proteins plays an essential role in many basic cellular processes. The UPS impacts transcriptional regulation by controlling the stability and thus, activity of numerous transcription factors (TFs). In Arabidopsis, trichome development and flavonoid metabolism are intimately connected, and several TFs have been identified that simultaneously control both processes. Here we show that UPS-dependent proteolysis of two of these TFs, GLABROUS 3 (GL3) and ENHANCER OF GL3 (EGL3) is mediated by ubiquitin protein ligase 3 (UPL3). Cell free degradation and in planta stabilization assays in the presence of MG132, an inhibitor of proteasome activity, demonstrated that degradation of GL3 and EGL3 proteins is 26S UPS-dependent. Yeast- or protoplast-based two-hybrid and bimolecular fluorescent complementation assays showed that GL3 and EGL3 interact via their C-terminal domains with the N-terminal portion of UPL3. Moreover, both TFs are stabilized and show increased activities in an upl3 mutant background. Gene expression analyses revealed that UPL3 expression is negatively affected by mutation in the gl3 locus but moderately up-regulated by over-expression of GL3, suggesting the presence of a regulatory loop involving GL3 and UPL3. Our findings underscore the importance of post-translational controls in epidermal cell differentiation and flavonoid metabolism.
  The Plant Journal 02/2013;
• Article: Potato CONSTANS is involved in photoperiodic tuberization in a graft-transmissible manner

  González-Schain ND, Díaz-Mendoza M, Zurczak M, Suárez-López P
  The Plant Journal 01/2012;
• Article: Fructokinase is required for carbon partitioning to cellulose in aspen wood.

  Roach M, Gerber L, Sandquist D, Gorzsás A, Hedenström M, Kumar M, Steinhauser MC, Feil R, Daniel G, Stitt M, Sundberg B, Niittylä T
  The Plant Journal 01/2012;
• Article: Inducible NAD overproduction in Arabidopsis alters metabolic pools and gene expression correlated with increased salicylate content and resistance to Pst-AvrRpm1

  Pétriacq Pierre, de Bont Linda, Hager Jutta, Didierlaurent Laure, Mauve Caroline, Guérard Florence, Noctor Graham, Pelletier Sandra, Renou Jean-Pierre, Tcherkez Guillaume, Gakière Bertrand
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  ABSTRACT: Plant development and function are underpinned by redox reactions that depend on cofactors such as nicotinamide adenine dinucleotide (NAD). NAD has recently been shown to be involved in several signalling pathways associated with stress tolerance or defence responses. Still, the mechanisms by which NAD influences plant gene regulation, metabolism and physiology remain unclear. Here, we took advantage of Arabidopsis thaliana lines overexpressing the nadC gene from E. coli, which encodes the NAD biosynthesis enzyme quinolinate phosphoribosyltransferase (QPT). Upon incubation with quinolinate, these lines accumulated NAD and were thus used as inducible systems to elucidate the consequences of an increased NAD content in leaves. Metabolic profiling showed clear changes in several metabolites such as aspartate-derived amino acids and NAD-derived nicotinic acid. Large-scale transcriptomic analyses indicated that NAD promoted the induction of various pathogen-related genes such as the salicylic acid (SA)-responsive defense marker PR1. Extensive comparison with transcriptomic databases further showed that gene expression under high NAD content was similar to that obtained under biotic stress, eliciting conditions or SA treatment. Upon inoculation with the avirulent strain of Pseudomonas syringae pv. tomato Pst-AvrRpm1, the nadC lines showed enhanced resistance to bacterial infection and exhibited a ICS1-dependent build-up of both conjugated and free SA pools. We therefore conclude that higher NAD contents are beneficial for plant immunity by stimulating SA-dependent signalling and pathogen resistance.
  The Plant Journal 01/2012;
• Article: Potato CONSTANS is involved in photoperiodic tuberization in a graft-transmissible manner

  Nahuel D. González-Schain, Mercedes Díaz-Mendoza, Marek Żurczak, Paula Suárez-López
  The Plant Journal 01/2012; doi: doi:10.1111/j.1365-313X.2012.04909.x.
• Article: Inducible NAD overproduction in Arabidopsis alters metabolic pools and gene expression correlated with increased salicylate content and resistance to Pst-AvrRpm1

  Pétriacq P, de Bont L, Hager J, Didierlaurent L, Mauve C, Guérard F, Noctor G, Pelletier S, Renou JP, Tcherkez G, Gakière B
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  ABSTRACT: Plant development and function are underpinned by redox reactions that depend on cofactors such as nicotinamide adenine dinucleotide (NAD). NAD has recently been shown to be involved in several signalling pathways associated with stress tolerance or defence responses. Still, the mechanisms by which NAD influences plant gene regulation, metabolism and physiology remain unclear. Here, we took advantage of Arabidopsis thaliana lines overexpressing the nadC gene from E. coli, which encodes the NAD biosynthesis enzyme quinolinate phosphoribosyltransferase (QPT). Upon incubation with quinolinate, these lines accumulated NAD and were thus used as inducible systems to elucidate the consequences of an increased NAD content in leaves. Metabolic profiling showed clear changes in several metabolites such as aspartate-derived amino acids and NAD-derived nicotinic acid. Large-scale transcriptomic analyses indicated that NAD promoted the induction of various pathogen-related genes such as the salicylic acid (SA)-responsive defense marker PR1. Extensive comparison with transcriptomic databases further showed that gene expression under high NAD content was similar to that obtained under biotic stress, eliciting conditions or SA treatment. Upon inoculation with the avirulent strain of Pseudomonas syringae pv. tomato Pst-AvrRpm1, the nadC lines showed enhanced resistance to bacterial infection and exhibited a ICS1-dependent build-up of both conjugated and free SA pools. We therefore conclude that higher NAD contents are beneficial for plant immunity by stimulating SA-dependent signalling and pathogen resistance.
  The Plant Journal 01/2012;
• Article: Knockdown of CENH3 in Arabidopsis reduces mitotic divisions and causes sterility by disturbed meiotic chromosome segregation

  Lermontova I, Koroleva O, Rutten T, Fuchs J, Schubert V, Moraes I, Koszegi D, Schubert I
  The Plant Journal 01/2011;
• Article: Cloning and characterization of a UV-B-inducible maizeflavonol synthase

  Maria Lorena Falcone Derreyra
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  ABSTRACT: Flavonols are important compounds for conditional male fertility in maize (Zea mays) and other crops, and they also contribute to protecting plants from UV-B radiation. However, little continues to be known on how maize and other grasses synthesize flavonols, and how flavonol biosynthesis is regulated. By homology with an Arabidopsis flavonol synthase (AtFLS1), we cloned a maize gene encoding a protein (ZmFLS1) capable of converting the dihydrokaempferol (DHK) and dihydroquercetin (DHQ) dihydroflavonols to the corresponding flavonols, kaempferol (K) and quercetin (Q). Moreover, ZmFLS1 partially complements the flavonol deficiency of the Arabidopsis fls1 mutant, and restores anthocyanin accumulation to normal levels. We demonstrate that ZmFLS1 is under the control of the anthocyanin (C1/PL1 + R/B) and 3-deoxy flavonoid (P1) transcriptional regulators. Indeed, using chromatin immunoprecipitation (ChIP) experiments, we establish that ZmFLS1 is an immediate direct target of the P1 and C1/R regulatory complexes, revealing similar control as for earlier steps in the maize flavonoid pathway. Highlighting the importance of flavonols in UV-B protection, we also show that ZmFLS1 is induced in maize seedlings by UV-B, and that this induction is in part mediated by the increased expression of the P1, B and PL1 regulators. Together, our results identify a key flavonoid biosynthetic enzyme so far missed in maize and other monocots, and illustrate mechanisms by which flavonol accumulation is controlled in maize.
  The Plant Journal 01/2010;
• Article: glucosinolate

  koroleva
  The Plant Journal 01/2010;
• Article: A putative transporter is essential for integrating nutrient and hormone signaling with lateral root growth and nodule development in Medicago truncatula

  Yendrek CR, Lee YC, Morris V, Liang Y, Pislariu CI, Burkart G, Meckfessel MH, Salehin M, Kessler H, Wessler H, Lloyd M, Lutton H, Teillet A, Sherrier DJ, Journet EP, Harris JM, Dickstein R
  The Plant Journal 01/2010; 62:100-12.
• Article: Biosynthesis of circular proteins in plants.

  Amanda D Gillon, Ivana Saska, Cameron V Jennings, Rosemary F Guarino, David J Craik, Marilyn A Anderson
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  ABSTRACT: Plant cyclotides are a large family of naturally occurring circular proteins that are produced from linear precursors containing one, two or three cyclotide domains. The mechanism of excision of the cyclotide domains and ligation of the free N- and C-termini to produce the circular peptides has not been elucidated. Here, we investigate production of the prototypic cyclotide kalata B1 from the precursor Oak1 from the African plant Oldenlandia affinis. Immunoprecipitation experiments and MALDI-TOF mass spectrometry analysis showed that O. affinis only produces mature kalata B1, whereas transgenic Arabidopsis thaliana, Nicotiana tabacum and Nicotiana benthamiana produced both linear and circular forms. Circular peptides were not produced when a highly conserved asparagine residue at the C-terminal processing site of the cyclotide domain was replaced with an alanine or an aspartate residue, or when the conserved C-terminal tripeptide motif was truncated. We propose that there are two processing pathways in planta: one to produce the mature cyclotide and the other to produce linear variants that ultimately cannot be cyclized.
  The Plant Journal 03/2008; 53(3):505-15.
• Article: LeafAnalyser: a computational method for rapid and large-scale analyses of leaf shape variation.

  Caroline Weight, Daniel Parnham, Richard Waites
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  ABSTRACT: A comprehensive understanding of leaf shape is important in many investigations in plant biology. Techniques to assess variation in leaf shape are often time-consuming, labour-intensive and prohibited by complex calculation of large data sets. We have developed LeafAnalyser, software that uses image-processing techniques to greatly simplify the measurement of leaf shape variation. LeafAnalyser places a large number of evenly distributed landmarks along leaf margins and records the position of each automatically. We used LeafAnalyser to analyse the variation in 3000 leaves from 400 plants of Antirrhinum majus. We were able to summarise the major trends in leaf shape variation using a principal components (PC) analysis and assess the changes in size, width and tip-to-base asymmetry within our leaf library. We demonstrate how this information can be used to develop a model that describes the range and variation of leaf shape within standard wild-type lines, and illustrate the shape transformations that occur between leaf nodes. We also show that information from LeafAnalyser can be used to identify novel trends in shape variation, as low-variance PCs that only affect a subset of position landmarks. These results provide a high-throughput method to calculate leaf shape variation that allows a large number of leaves to be visualised in higher-dimensional phenotypic space. To illustrate the applicability of LeafAnalyser we also calculated the leaf shape variation in 300 leaves from Arabidopsis thaliana.
  The Plant Journal 03/2008; 53(3):578-86.