TY - JOUR AB - The ability to adapt growth and development to temperature variations is crucial to generate plant varieties resilient to predicted temperature changes. However, the mechanisms underlying plant response to progressive increases in temperature have just started to be elucidated. Here, we report that the Cyclin-dependent Kinase G1 (CDKG1) is a central element in a thermo-sensitive mRNA splicing cascade that transduces changes in ambient temperature into differential expression of the fundamental spliceosome component, ATU2AF65A. CDKG1 is alternatively spliced in a temperature-dependent manner. We found that this process is partly dependent on both the Cyclin-dependent Kinase G2 (CDKG2) and the interacting co-factor CYCLIN L1 resulting in two distinct messenger RNAs. Relative abundance of both CDKG1 transcripts correlates with ambient temperature and possibly with different expression levels of the associated protein isoforms. Both CDKG1 alternative transcripts are necessary to fully complement the expression of ATU2AF65A across the temperature range. Our data support a previously unidentified temperature-dependent mechanism based on the alternative splicing of CDKG1 and regulated by CDKG2 and CYCLIN L1. We propose that changes in ambient temperature affect the relative abundance of CDKG1 transcripts and this in turn translates into differential CDKG1 protein expression coordinating the alternative splicing of ATU2AF65A. This article is protected by copyright. All rights reserved. AU - Cavallari, Nicola AU - Nibau, Candida AU - Fuchs, Armin AU - Dadarou, Despoina AU - Barta, Andrea AU - Doonan, John ID - 403 IS - 6 JF - The Plant Journal TI - The cyclin‐dependent kinase G group defines a thermo‐sensitive alternative splicing circuit modulating the expression of Arabidopsis ATU 2AF 65A VL - 94 ER - TY - THES AB - The whole life cycle of plants as well as their responses to environmental stimuli is governed by a complex network of hormonal regulations. A number of studies have demonstrated an essential role of both auxin and cytokinin in the regulation of many aspects of plant growth and development including embryogenesis, postembryonic organogenic processes such as root, and shoot branching, root and shoot apical meristem activity and phyllotaxis. Over the last decades essential knowledge on the key molecular factors and pathways that spatio-temporally define auxin and cytokinin activities in the plant body has accumulated. However, how both hormonal pathways are interconnected by a complex network of interactions and feedback circuits that determines the final outcome of the individual hormone actions is still largely unknown. Root system architecture establishment and in particular formation of lateral organs is prime example of developmental process at whose regulation both auxin and cytokinin pathways converge. To dissect convergence points and pathways that tightly balance auxin - cytokinin antagonistic activities that determine the root branching pattern transcriptome profiling was applied. Genome wide expression analyses of the xylem pole pericycle, a tissue giving rise to lateral roots, led to identification of genes that are highly responsive to combinatorial auxin and cytokinin treatments and play an essential function in the auxin-cytokinin regulated root branching. SYNERGISTIC AUXIN CYTOKININ 1 (SYAC1) gene, which encodes for a protein of unknown function, was detected among the top candidate genes of which expression was synergistically up-regulated by simultaneous hormonal treatment. Plants with modulated SYAC1 activity exhibit severe defects in the root system establishment and attenuate developmental responses to both auxin and cytokinin. To explore the biological function of the SYAC1, we employed different strategies including expression pattern analysis, subcellular localization and phenotypic analyses of the syac1 loss-of-function and gain-of-function transgenic lines along with the identification of the SYAC1 interaction partners. Detailed functional characterization revealed that SYAC1 acts as a developmentally specific regulator of the secretory pathway to control deposition of cell wall components and thereby rapidly fine tune elongation growth. AU - Hurny, Andrej ID - 539 SN - 2663-337X TI - Identification and characterization of novel auxin-cytokinin cross-talk components ER - TY - JOUR AB - Intercellular distribution of the plant hormone auxin largely depends on the polar subcellular distribution of the plasma membrane PIN-FORMED (PIN) auxin transporters. PIN polarity switches in response to different developmental and environmental signals have been shown to redirect auxin fluxes mediating certain developmental responses. PIN phosphorylation at different sites and by different kinases is crucial for PIN function. Here we investigate the role of PIN phosphorylation during gravitropic response. Loss- and gain-of-function mutants in PINOID and related kinases but not in D6PK kinase as well as mutations mimicking constitutive dephosphorylated or phosphorylated status of two clusters of predicted phosphorylation sites partially disrupted PIN3 phosphorylation and caused defects in gravitropic bending in roots and hypocotyls. In particular, they impacted PIN3 polarity rearrangements in response to gravity and during feed-back regulation by auxin itself. Thus PIN phosphorylation, besides regulating transport activity and apical-basal targeting, is also important for the rapid polarity switches in response to environmental and endogenous signals. AU - Grones, Peter AU - Abas, Melinda F AU - Hajny, Jakub AU - Jones, Angharad AU - Waidmann, Sascha AU - Kleine Vehn, Jürgen AU - Friml, Jirí ID - 191 IS - 1 JF - Scientific Reports TI - PID/WAG-mediated phosphorylation of the Arabidopsis PIN3 auxin transporter mediates polarity switches during gravitropism VL - 8 ER - TY - JOUR AB - Plant hormones as signalling molecules play an essential role in the control of plant growth and development. Typically, sites of hormonal action are usually distant from the site of biosynthesis thus relying on efficient transport mechanisms. Over the last decades, molecular identification of proteins and protein complexes involved in hormonal transport has started. Advanced screens for genes involved in hormonal transport in combination with transport assays using heterologous systems such as yeast, insect, or tobacco BY2 cells or Xenopus oocytes provided important insights into mechanisms underlying distribution of hormones in plant body and led to identification of principal transporters for each hormone. This review gives a short overview of the mechanisms of hormonal transport and transporters identified in Arabidopsis thaliana. AU - Abualia, Rashed AU - Benková, Eva AU - Lacombe, Benoît ID - 47 JF - Advances in Botanical Research TI - Transporters and mechanisms of hormone transport in arabidopsis VL - 87 ER - TY - JOUR AB - In plants, the multistep phosphorelay (MSP) pathway mediates a range of regulatory processes, including those activated by cytokinins. The crosstalk between cytokinin response and light is known for a long time. However, the molecular mechanism underlying the interactionbetween light and cytokinin signaling remains elusive. In the screen for upstream regulators we identified a LONG PALE HYPOCOTYL (LPH) gene whose activity is indispensable for spatiotemporally correct expression of CYTOKININ INDEPENDENT-1 (CKI1), encoding the constitutively active sensor histidine kinase that activates MSP signaling. lph is a new allele of HEME OXYGENASE 1 (HY1) which encodes the key protein in the biosynthesis of phytochromobilin, a cofactor of photoconvertiblephytochromes. Our analysis confirmed the light-dependent regulation oftheCKI1 expression pattern. We show that CKI1 expression is under the control of phytochrome A (phyA), functioning as a dual (both positive and negative) regulator of CKI1 expression, presumably via the phyA-regulated transcription factors PHYTOCHROME INTERACTING FACTOR 3 (PIF3) and CIRCADIAN CLOCK ASSOCIATED 1 (CCA1). Changes in CKI1 expression observed in lph/hy1-7 and phy mutants correlatewithmisregulation of MSP signaling, changedcytokinin sensitivity and developmental aberrations,previously shown to be associated with cytokinin and/or CKI1 action. Besides that, we demonstrate novel role of phyA-dependent CKI1 expression in the hypocotyl elongation and hook development during skotomorphogenesis. Based on these results, we propose that the light-dependent regulation of CKI1 provides a plausible mechanistic link underlying the well-known interaction between light- and cytokinin-controlled plant development. AU - Dobisova, Tereza AU - Hrdinova, Vendula AU - Cuesta, Candela AU - Michlickova, Sarka AU - Urbankova, Ivana AU - Hejatkova, Romana AU - Zadnikova, Petra AU - Pernisová, Markéta AU - Benková, Eva AU - Hejátko, Jan ID - 1018 IS - 1 JF - Plant Physiology TI - Light regulated expression of sensor histidine kinase CKI1 controls cytokinin related development VL - 174 ER - TY - JOUR AB - The fundamental tasks of the root system are, besides anchoring, mediating interactions between plant and soil and providing the plant with water and nutrients. The architecture of the root system is controlled by endogenous mechanisms that constantly integrate environmental signals, such as availability of nutrients and water. Extremely important for efficient soil exploitation and survival under less favorable conditions is the developmental flexibility of the root system that is largely determined by its postembryonic branching capacity. Modulation of initiation and outgrowth of lateral roots provides roots with an exceptional plasticity, allows optimal adjustment to underground heterogeneity, and enables effective soil exploitation and use of resources. Here we discuss recent advances in understanding the molecular mechanisms that shape the plant root system and integrate external cues to adapt to the changing environment. AU - Ötvös, Krisztina AU - Benková, Eva ID - 1004 JF - Current Opinion in Genetics & Development SN - 0959437X TI - Spatiotemporal mechanisms of root branching VL - 45 ER - TY - JOUR AB - Roots navigate through soil integrating environmental signals to orient their growth. The Arabidopsis root is a widely used model for developmental, physiological and cell biological studies. Live imaging greatly aids these efforts, but the horizontal sample position and continuous root tip displacement present significant difficulties. Here, we develop a confocal microscope setup for vertical sample mounting and integrated directional illumination. We present TipTracker – a custom software for automatic tracking of diverse moving objects usable on various microscope setups. Combined, this enables observation of root tips growing along the natural gravity vector over prolonged periods of time, as well as the ability to induce rapid gravity or light stimulation. We also track migrating cells in the developing zebrafish embryo, demonstrating the utility of this system in the acquisition of high-resolution data sets of dynamic samples. We provide detailed descriptions of the tools enabling the easy implementation on other microscopes. AU - Von Wangenheim, Daniel AU - Hauschild, Robert AU - Fendrych, Matyas AU - Barone, Vanessa AU - Benková, Eva AU - Friml, Jirí ID - 946 JF - eLife TI - Live tracking of moving samples in confocal microscopy for vertically grown roots VL - 6 ER - TY - JOUR AB - The history of auxin and cytokinin biology including the initial discoveries by father–son duo Charles Darwin and Francis Darwin (1880), and Gottlieb Haberlandt (1919) is a beautiful demonstration of unceasing continuity of research. Novel findings are integrated into existing hypotheses and models and deepen our understanding of biological principles. At the same time new questions are triggered and hand to hand with this new methodologies are developed to address these new challenges. AU - Hurny, Andrej AU - Benková, Eva ID - 1024 JF - Auxins and Cytokinins in Plant Biology SN - 10643745 TI - Methodological advances in auxin and cytokinin biology VL - 1569 ER - TY - JOUR AB - The asymmetric localization of proteins in the plasma membrane domains of eukaryotic cells is a fundamental manifestation of cell polarity that is central to multicellular organization and developmental patterning. In plants, the mechanisms underlying the polar localization of cargo proteins are still largely unknown and appear to be fundamentally distinct from those operating in mammals. Here, we present a systematic, quantitative comparative analysis of the polar delivery and subcellular localization of proteins that characterize distinct polar plasma membrane domains in plant cells. The combination of microscopic analyses and computational modeling revealed a mechanistic framework common to diverse polar cargos and underlying the establishment and maintenance of apical, basal, and lateral polar domains in plant cells. This mechanism depends on the polar secretion, constitutive endocytic recycling, and restricted lateral diffusion of cargos within the plasma membrane. Moreover, our observations suggest that polar cargo distribution involves the individual protein potential to form clusters within the plasma membrane and interact with the extracellular matrix. Our observations provide insights into the shared cellular mechanisms of polar cargo delivery and polarity maintenance in plant cells. AU - Łangowski, Łukasz AU - Wabnik, Krzysztof T AU - Li, Hongjiang AU - Vanneste, Steffen AU - Naramoto, Satoshi AU - Tanaka, Hirokazu AU - Friml, Jirí ID - 1081 JF - Cell Discovery TI - Cellular mechanisms for cargo delivery and polarity maintenance at different polar domains in plant cells VL - 2 ER - TY - JOUR AB - Differential cell growth enables flexible organ bending in the presence of environmental signals such as light or gravity. A prominent example of the developmental processes based on differential cell growth is the formation of the apical hook that protects the fragile shoot apical meristem when it breaks through the soil during germination. Here, we combined in silico and in vivo approaches to identify a minimal mechanism producing auxin gradient-guided differential growth during the establishment of the apical hook in the model plant Arabidopsis thaliana. Computer simulation models based on experimental data demonstrate that asymmetric expression of the PIN-FORMED auxin efflux carrier at the concave (inner) versus convex (outer) side of the hook suffices to establish an auxin maximum in the epidermis at the concave side of the apical hook. Furthermore, we propose a mechanism that translates this maximum into differential growth, and thus curvature, of the apical hook. Through a combination of experimental and in silico computational approaches, we have identified the individual contributions of differential cell elongation and proliferation to defining the apical hook and reveal the role of auxin-ethylene crosstalk in balancing these two processes. © 2016 American Society of Plant Biologists. All rights reserved. AU - Žádníková, Petra AU - Wabnik, Krzysztof T AU - Abuzeineh, Anas AU - Gallemí, Marçal AU - Van Der Straeten, Dominique AU - Smith, Richard AU - Inze, Dirk AU - Friml, Jirí AU - Prusinkiewicz, Przemysław AU - Benková, Eva ID - 1153 IS - 10 JF - Plant Cell TI - A model of differential growth guided apical hook formation in plants VL - 28 ER - TY - JOUR AB - The developmental programme of the pistil is under the control of both auxin and cytokinin. Crosstalk between these factors converges on regulation of the auxin carrier PIN-FORMED 1 (PIN1). Here, we show that in the triple transcription factor mutant cytokinin response factor 2 (crf2) crf3 crf6 both pistil length and ovule number were reduced. PIN1 expression was also lower in the triple mutant and the phenotypes could not be rescued by exogenous cytokinin application. pin1 complementation studies using genomic PIN1 constructs showed that the pistil phenotypes were only rescued when the PCRE1 domain, to which CRFs bind, was present. Without this domain, pin mutants resemble the crf2 crf3 crf6 triple mutant, indicating the pivotal role of CRFs in auxin-cytokinin crosstalk. AU - Cucinotta, Mara AU - Manrique, Silvia AU - Guazzotti, Andrea AU - Quadrelli, Nadia AU - Mendes, Marta AU - Benková, Eva AU - Colombo, Lucia ID - 1185 IS - 23 JF - Development TI - Cytokinin response factors integrate auxin and cytokinin pathways for female reproductive organ development VL - 143 ER - TY - CHAP AB - Mechanisms for cell protection are essential for survival of multicellular organisms. In plants, the apical hook, which is transiently formed in darkness when the germinating seedling penetrates towards the soil surface, plays such protective role and shields the vitally important shoot apical meristem and cotyledons from damage. The apical hook is formed by bending of the upper hypocotyl soon after germination, and it is maintained in a closed stage while the hypocotyl continues to penetrate through the soil and rapidly opens when exposed to light in proximity of the soil surface. To uncover the complex molecular network orchestrating this spatiotemporally tightly coordinated process, monitoring of the apical hook development in real time is indispensable. Here we describe an imaging platform that enables high-resolution kinetic analysis of this dynamic developmental process. © Springer Science+Business Media New York 2017. AU - Zhu, Qiang AU - Žádníková, Petra AU - Smet, Dajo AU - Van Der Straeten, Dominique AU - Benková, Eva ID - 1210 T2 - Plant Hormones TI - Real time analysis of the apical hook development VL - 1497 ER - TY - JOUR AB - When plants grow in close proximity basic resources such as light can become limiting. Under such conditions plants respond to anticipate and/or adapt to the light shortage, a process known as the shade avoidance syndrome (SAS). Following genetic screening using a shade-responsive luciferase reporter line (PHYB:LUC), we identified DRACULA2 (DRA2), which encodes an Arabidopsis homolog of mammalian nucleoporin 98, a component of the nuclear pore complex (NPC). DRA2, together with other nucleoporins, participates positively in the control of the hypocotyl elongation response to plant proximity, a role that can be considered dependent on the nucleocytoplasmic transport of macromolecules (i.e. is transport dependent). In addition, our results reveal a specific role for DRA2 in controlling shade-induced gene expression. We suggest that this novel regulatory role of DRA2 is transport independent and that it might rely on its dynamic localization within and outside of the NPC. These results provide mechanistic insights in to how SAS responses are rapidly established by light conditions. They also indicate that nucleoporins have an active role in plant signaling. AU - Gallemi Rovira, Marcal AU - Galstyan, Anahit AU - Paulišić, Sandi AU - Then, Christiane AU - Ferrández Ayela, Almudena AU - Lorenzo Orts, Laura AU - Roig Villanova, Irma AU - Wang, Xuewen AU - Micol, José AU - Ponce, Maria AU - Devlin, Paul AU - Martínez García, Jaime ID - 1258 IS - 9 JF - Development TI - DRACULA2 is a dynamic nucleoporin with a role in regulating the shade avoidance syndrome in Arabidopsis VL - 143 ER - TY - JOUR AB - n contrast with the wealth of recent reports about the function of μ-adaptins and clathrin adaptor protein (AP) complexes, there is very little information about the motifs that determine the sorting of membrane proteins within clathrin-coated vesicles in plants. Here, we investigated putative sorting signals in the large cytosolic loop of the Arabidopsis (Arabidopsis thaliana) PIN-FORMED1 (PIN1) auxin transporter, which are involved in binding μ-adaptins and thus in PIN1 trafficking and localization. We found that Phe-165 and Tyr-280, Tyr-328, and Tyr-394 are involved in the binding of different μ-adaptins in vitro. However, only Phe-165, which binds μA(μ2)- and μD(μ3)-adaptin, was found to be essential for PIN1 trafficking and localization in vivo. The PIN1:GFP-F165A mutant showed reduced endocytosis but also localized to intracellular structures containing several layers of membranes and endoplasmic reticulum (ER) markers, suggesting that they correspond to ER or ER-derived membranes. While PIN1:GFP localized normally in a μA (μ2)-adaptin mutant, it accumulated in big intracellular structures containing LysoTracker in a μD (μ3)-adaptin mutant, consistent with previous results obtained with mutants of other subunits of the AP-3 complex. Our data suggest that Phe-165, through the binding of μA (μ2)- and μD (μ3)-adaptin, is important for PIN1 endocytosis and for PIN1 trafficking along the secretory pathway, respectively. AU - Sancho Andrés, Gloria AU - Soriano Ortega, Esther AU - Gao, Caiji AU - Bernabé Orts, Joan AU - Narasimhan, Madhumitha AU - Müller, Anna AU - Tejos, Ricardo AU - Jiang, Liwen AU - Friml, Jirí AU - Aniento, Fernando AU - Marcote, Maria ID - 1264 IS - 3 JF - Plant Physiology TI - Sorting motifs involved in the trafficking and localization of the PIN1 auxin efflux carrier VL - 171 ER - TY - JOUR AB - Extracellular matrices (ECMs) are central to the advent of multicellular life, and their mechanical propertiesare modulated by and impinge on intracellular signaling pathways that regulate vital cellular functions. High spatial-resolution mapping of mechanical properties in live cells is, however, extremely challenging. Thus, our understanding of how signaling pathways process physiological signals to generate appropriate mechanical responses is limited. We introduce fluorescence emission-Brillouin scattering imaging (FBi), a method for the parallel and all-optical measurements of mechanical properties and fluorescence at the submicrometer scale in living organisms. Using FBi, we showed thatchanges in cellular hydrostatic pressure and cytoplasm viscoelasticity modulate the mechanical signatures of plant ECMs. We further established that the measured "stiffness" of plant ECMs is symmetrically patternedin hypocotyl cells undergoing directional growth. Finally, application of this method to Arabidopsis thaliana with photoreceptor mutants revealed that red and far-red light signals are essential modulators of ECM viscoelasticity. By mapping the viscoelastic signatures of a complex ECM, we provide proof of principlefor the organism-wide applicability of FBi for measuring the mechanical outputs of intracellular signaling pathways. As such, our work has implications for investigations of mechanosignaling pathways and developmental biology. AU - Elsayad, Kareem AU - Werner, Stephanie AU - Gallemi Rovira, Marcal AU - Kong, Jixiang AU - Guajardo, Edmundo AU - Zhang, Lijuan AU - Jaillais, Yvon AU - Greb, Thomas AU - Belkhadir, Youssef ID - 1265 IS - 435 JF - Science Signaling TI - Mapping the subcellular mechanical properties of live cells in tissues with fluorescence emission-Brillouin imaging VL - 9 ER - TY - JOUR AB - Plants are continuously exposed to a myriad of external signals such as fluctuating nutrients availability, drought, heat, cold, high salinity, or pathogen/pest attacks that can severely affect their development, growth, and fertility. As sessile organisms, plants must therefore be able to sense and rapidly react to these external inputs, activate efficient responses, and adjust development to changing conditions. In recent years, significant progress has been made towards understanding the molecular mechanisms underlying the intricate and complex communication between plants and the environment. It is now becoming increasingly evident that hormones have an important regulatory role in plant adaptation and defense mechanisms. AU - Benková, Eva ID - 1269 IS - 6 JF - Plant Molecular Biology TI - Plant hormones in interactions with the environment VL - 91 ER - TY - JOUR AB - Lateral root primordia (LRP) originate from pericycle stem cells located deep within parental root tissues. LRP emerge through overlying root tissues by inducing auxin-dependent cell separation and hydraulic changes in adjacent cells. The auxin-inducible auxin influx carrier LAX3 plays a key role concentrating this signal in cells overlying LRP. Delimiting LAX3 expression to two adjacent cell files overlying new LRP is crucial to ensure that auxin-regulated cell separation occurs solely along their shared walls. Multiscale modeling has predicted that this highly focused pattern of expression requires auxin to sequentially induce auxin efflux and influx carriers PIN3 and LAX3, respectively. Consistent with model predictions, we report that auxin-inducible LAX3 expression is regulated indirectly by AUXIN RESPONSE FACTOR 7 (ARF7). Yeast one-hybrid screens revealed that the LAX3 promoter is bound by the transcription factor LBD29, which is a direct target for regulation by ARF7. Disrupting auxin-inducible LBD29 expression or expressing an LBD29-SRDX transcriptional repressor phenocopied the lax3 mutant, resulting in delayed lateral root emergence. We conclude that sequential LBD29 and LAX3 induction by auxin is required to coordinate cell separation and organ emergence. AU - Porco, Silvana AU - Larrieu, Antoine AU - Du, Yujuan AU - Gaudinier, Allison AU - Goh, Tatsuaki AU - Swarup, Kamal AU - Swarup, Ranjan AU - Kuempers, Britta AU - Bishopp, Anthony AU - Lavenus, Julien AU - Casimiro, Ilda AU - Hill, Kristine AU - Benková, Eva AU - Fukaki, Hidehiro AU - Brady, Siobhan AU - Scheres, Ben AU - Peéet, Benjamin AU - Bennett, Malcolm ID - 1273 IS - 18 JF - Development TI - Lateral root emergence in Arabidopsis is dependent on transcription factor LBD29 regulation of auxin influx carrier LAX3 VL - 143 ER - TY - JOUR AB - Plants are able to modulate root growth and development to optimize their nitrogen nutrition. In Arabidopsis (Arabidopsis thaliana), the adaptive root response to nitrate (NO3 -) depends on the NRT1.1/NPF6.3 transporter/sensor. NRT1.1 represses emergence of lateral root primordia (LRPs) at low concentration or absence of NO3 - through its auxin transport activity that lowers auxin accumulation in LR. However, these functional data strongly contrast with the known transcriptional regulation of NRT1.1, which is markedly repressed in LRPs in the absence of NO3 -. To explain this discrepancy, we investigated in detail the spatiotemporal expression pattern of the NRT1.1 protein during LRP development and combined local transcript analysis with the use of transgenic lines expressing tagged NRT1.1 proteins. Our results show that although NO3 - stimulates NRT1.1 transcription and probably mRNA stability both in primary root tissues and in LRPs, it acts differentially on protein accumulation, depending on the tissues considered with stimulation in cortex and epidermis of the primary root and a strong repression in LRPs and to a lower extent at the primary root tip. This demonstrates that NRT1.1 is strongly regulated at the posttranscriptional level by tissue-specific mechanisms. These mechanisms are crucial for controlling the large palette of adaptive responses to NO3 - mediated by NRT1.1 as they ensure that the protein is present in the proper tissue under the specific conditions where it plays a signaling role in this particular tissue. AU - Bouguyon, Eléonore AU - Perrine Walker, Francine AU - Pervent, Marjorie AU - Rochette, Juliette AU - Cuesta, Candela AU - Benková, Eva AU - Martinière, Alexandre AU - Bach, Lien AU - Krouk, Gabriel AU - Gojon, Alain AU - Nacry, Philippe ID - 1281 IS - 2 JF - Plant Physiology TI - Nitrate controls root development through posttranscriptional regulation of the NRT1.1/NPF6.3 transporter sensor VL - 172 ER - TY - JOUR AB - The impact of the plant hormone ethylene on seedling development has long been recognized; however, its ecophysiological relevance is unexplored. Three recent studies demonstrate that ethylene is a critical endogenous integrator of various environmental signals including mechanical stress, light, and oxygen availability during seedling germination and growth through the soil. AU - Zhu, Qiang AU - Benková, Eva ID - 1283 IS - 10 JF - Trends in Plant Science TI - Seedlings’ strategy to overcome a soil barrier VL - 21 ER - TY - JOUR AB - Cytokinin is a phytohormone that is well known for its roles in numerous plant growth and developmental processes, yet it has also been linked to abiotic stress response in a less defined manner. Arabidopsis (Arabidopsis thaliana) Cytokinin Response Factor 6 (CRF6) is a cytokinin-responsive AP2/ERF-family transcription factor that, through the cytokinin signaling pathway, plays a key role in the inhibition of dark-induced senescence. CRF6 expression is also induced by oxidative stress, and here we show a novel function for CRF6 in relation to oxidative stress and identify downstream transcriptional targets of CRF6 that are repressed in response to oxidative stress. Analysis of transcriptomic changes in wild-type and crf6 mutant plants treated with H2O2 identified CRF6-dependent differentially expressed transcripts, many of which were repressed rather than induced. Moreover, many repressed genes also show decreased expression in 35S:CRF6 overexpressing plants. Together, these findings suggest that CRF6 functions largely as a transcriptional repressor. Interestingly, among the H2O2 repressed CRF6-dependent transcripts was a set of five genes associated with cytokinin processes: (signaling) ARR6, ARR9, ARR11, (biosynthesis) LOG7, and (transport) ABCG14. We have examined mutants of these cytokinin-associated target genes to reveal novel connections to oxidative stress. Further examination of CRF6-DNA interactions indicated that CRF6 may regulate its targets both directly and indirectly. Together, this shows that CRF6 functions during oxidative stress as a negative regulator to control this cytokinin-associated module of CRF6- dependent genes and establishes a novel connection between cytokinin and oxidative stress response. AU - Zwack, Paul AU - De Clercq, Inge AU - Howton, Timothy AU - Hallmark, H Tucker AU - Hurny, Andrej AU - Keshishian, Erika AU - Parish, Alyssa AU - Benková, Eva AU - Mukhtar, M Shahid AU - Van Breusegem, Frank AU - Rashotte, Aaron ID - 1331 IS - 2 JF - Plant Physiology SN - 0032-0889 TI - Cytokinin response factor 6 represses cytokinin-associated genes during oxidative stress VL - 172 ER -