TY - GEN AB - Eva Benkova received a PhD in Biophysics at the Institute of Biophysics of the Czech Academy of Sciences in 1998. After working as a postdoc at the Max Planck Institute in Cologne and the Center for Plant Molecular Biology (ZMBP) in Tübingen, she became a group leader at the Plant Systems Biology Department of the Vlaams Instituut voor Biotechnologie (VIB) in Gent. In 2012, she transitioned to an Assistant Professor position at the Institute of Science and Technology Austria (ISTA) where she was later promoted to Professor. Since 2021, she has served as the Dean of the ISTA Graduate School. As a plant developmental biologist, she focuses on unraveling the molecular mechanisms and principles that underlie hormonal interactions in plants. In her current work, she explores the intricate connections between hormones and regulatory pathways that mediate the perception of environmental stimuli, including abiotic stress and nitrate availability. AU - Benková, Eva ID - 14842 IS - 1 T2 - Current Biology TI - Eva Benkova VL - 34 ER - TY - JOUR AB - Epithelial barrier function is commonly analyzed using transepithelial electrical resistance, which measures ion flux across a monolayer, or by adding traceable macromolecules and monitoring their passage across the monolayer. Although these methods measure changes in global barrier function, they lack the sensitivity needed to detect local or transient barrier breaches, and they do not reveal the location of barrier leaks. Therefore, we previously developed a method that we named the zinc-based ultrasensitive microscopic barrier assay (ZnUMBA), which overcomes these limitations, allowing for detection of local tight junction leaks with high spatiotemporal resolution. Here, we present expanded applications for ZnUMBA. ZnUMBA can be used in Xenopus embryos to measure the dynamics of barrier restoration and actin accumulation following laser injury. ZnUMBA can also be effectively utilized in developing zebrafish embryos as well as cultured monolayers of Madin–Darby canine kidney (MDCK) II epithelial cells. ZnUMBA is a powerful and flexible method that, with minimal optimization, can be applied to multiple systems to measure dynamic changes in barrier function with spatiotemporal precision. AU - Higashi, Tomohito AU - Stephenson, Rachel E. AU - Schwayer, Cornelia AU - Huljev, Karla AU - Higashi, Atsuko Y. AU - Heisenberg, Carl-Philipp J AU - Chiba, Hideki AU - Miller, Ann L. ID - 14082 IS - 15 JF - Journal of Cell Science SN - 0021-9533 TI - ZnUMBA - a live imaging method to detect local barrier breaches VL - 136 ER - TY - JOUR AB - Nitrogen is an important macronutrient required for plant growth and development, thus directly impacting agricultural productivity. In recent years, numerous studies have shown that nitrogen-driven growth depends on pathways that control nitrate/nitrogen homeostasis and hormonal networks that act both locally and systemically to coordinate growth and development of plant organs. In this review, we will focus on recent advances in understanding the role of the plant hormones auxin and cytokinin and their crosstalk in nitrate-regulated growth and discuss the significance of novel findings and possible missing links. AU - Abualia, R AU - Riegler, Stefan AU - Benková, Eva ID - 13214 IS - 12 JF - Cells SN - 2073-4409 TI - Nitrate, auxin and cytokinin - a trio to tango VL - 12 ER - TY - JOUR AB - Mineral nutrition is one of the key environmental factors determining plant development and growth. Nitrate is the major form of macronutrient nitrogen that plants take up from the soil. Fluctuating availability or deficiency of this element severely limits plant growth and negatively affects crop production in the agricultural system. To cope with the heterogeneity of nitrate distribution in soil, plants evolved a complex regulatory mechanism that allows rapid adjustment of physiological and developmental processes to the status of this nutrient. The root, as a major exploitation organ that controls the uptake of nitrate to the plant body, acts as a regulatory hub that, according to nitrate availability, coordinates the growth and development of other plant organs. Here, we identified a regulatory framework, where cytokinin response factors (CRFs) play a central role as a molecular readout of the nitrate status in roots to guide shoot adaptive developmental response. We show that nitrate-driven activation of NLP7, a master regulator of nitrate response in plants, fine tunes biosynthesis of cytokinin in roots and its translocation to shoots where it enhances expression of CRFs. CRFs, through direct transcriptional regulation of PIN auxin transporters, promote the flow of auxin and thereby stimulate the development of shoot organs. AU - Abualia, Rashed AU - Ötvös, Krisztina AU - Novák, Ondřej AU - Bouguyon, Eleonore AU - Domanegg, Kevin AU - Krapp, Anne AU - Nacry, Philip AU - Gojon, Alain AU - Lacombe, Benoit AU - Benková, Eva ID - 11734 IS - 31 JF - Proceedings of the National Academy of Sciences of the United States of America TI - Molecular framework integrating nitrate sensing in root and auxin-guided shoot adaptive responses VL - 119 ER - TY - JOUR AB - The phytohormone auxin triggers transcriptional reprogramming through a well-characterized perception machinery in the nucleus. By contrast, mechanisms that underlie fast effects of auxin, such as the regulation of ion fluxes, rapid phosphorylation of proteins or auxin feedback on its transport, remain unclear1,2,3. Whether auxin-binding protein 1 (ABP1) is an auxin receptor has been a source of debate for decades1,4. Here we show that a fraction of Arabidopsis thaliana ABP1 is secreted and binds auxin specifically at an acidic pH that is typical of the apoplast. ABP1 and its plasma-membrane-localized partner, transmembrane kinase 1 (TMK1), are required for the auxin-induced ultrafast global phospho-response and for downstream processes that include the activation of H+-ATPase and accelerated cytoplasmic streaming. abp1 and tmk mutants cannot establish auxin-transporting channels and show defective auxin-induced vasculature formation and regeneration. An ABP1(M2X) variant that lacks the capacity to bind auxin is unable to complement these defects in abp1 mutants. These data indicate that ABP1 is the auxin receptor for TMK1-based cell-surface signalling, which mediates the global phospho-response and auxin canalization. AU - Friml, Jiří AU - Gallei, Michelle C AU - Gelová, Zuzana AU - Johnson, Alexander J AU - Mazur, Ewa AU - Monzer, Aline AU - Rodriguez Solovey, Lesia AU - Roosjen, Mark AU - Verstraeten, Inge AU - Živanović, Branka D. AU - Zou, Minxia AU - Fiedler, Lukas AU - Giannini, Caterina AU - Grones, Peter AU - Hrtyan, Mónika AU - Kaufmann, Walter AU - Kuhn, Andre AU - Narasimhan, Madhumitha AU - Randuch, Marek AU - Rýdza, Nikola AU - Takahashi, Koji AU - Tan, Shutang AU - Teplova, Anastasiia AU - Kinoshita, Toshinori AU - Weijers, Dolf AU - Rakusová, Hana ID - 12291 IS - 7927 JF - Nature SN - 0028-0836 TI - ABP1–TMK auxin perception for global phosphorylation and auxin canalization VL - 609 ER - TY - THES AB - As the overall global mean surface temperature is increasing due to climate change, plant adaptation to those stressful conditions is of utmost importance for their survival. Plants are sessile organisms, thus to compensate for their lack of mobility, they evolved a variety of mechanisms enabling them to flexibly adjust their physiological, growth and developmental processes to fluctuating temperatures and to survive in harsh environments. While these unique adaptation abilities provide an important evolutionary advantage, overall modulation of plant growth and developmental program due to non-optimal temperature negatively affects biomass production, crop productivity or sensitivity to pathogens. Thus, understanding molecular processes underlying plant adaptation to increased temperature can provide important resources for breeding strategies to ensure sufficient agricultural food production. An increase in ambient temperature by a few degrees leads to profound changes in organ growth including enhanced hypocotyl elongation, expansion of petioles, hyponastic growth of leaves and cotyledons, collectively named thermomorphogenesis (Casal & Balasubramanian, 2019). Auxin, one of the best-studied growth hormones, plays an essential role in this process by direct activation of transcriptional and non-transcriptional processes resulting in elongation growth (Majda & Robert, 2018).To modulate hypocotyl growth in response to high ambient temperature (hAT), auxin needs to be redistributed accordingly. PINs, auxin efflux transporters, are key components of the polar auxin transport (PAT) machinery, which controls the amount and direction of auxin translocated in the plant tissues and organs(Adamowski & Friml, 2015). Hence, PIN-mediated transport is tightly linked with thermo-morphogenesis, and interference with PAT through either chemical or genetic means dramatically affecting the adaptive responses to hAT. Intriguingly, despite the key role of PIN mediated transport in growth response to hAT, whether and how PINs at the level of expression adapt to fluctuation in temperature is scarcely understood. With genetic, molecular and advanced bio-imaging approaches, we demonstrate the role of PIN auxin transporters in the regulation of hypocotyl growth in response to hAT. We show that via adjustment of PIN3, PIN4 and PIN7 expression in cotyledons and hypocotyls, auxin distribution is modulated thereby determining elongation pattern of epidermal cells at hAT. Furthermore, we identified three Zinc-Finger (ZF) transcription factors as novel molecular components of the thermo-regulatory network, which through negative regulation of PIN transcription adjust the transport of auxin at hAT. Our results suggest that the ZF-PIN module might be a part of the negative feedback loop attenuating the activity of the thermo-sensing pathway to restrain exaggerated growth and developmental responses to hAT. AU - Artner, Christina ID - 11879 KW - high ambient temperature KW - auxin KW - PINs KW - Zinc-Finger proteins KW - thermomorphogenesis KW - stress SN - 2663-337X TI - Modulation of auxin transport via ZF proteins adjust plant response to high ambient temperature ER - TY - JOUR AB - Cell and tissue polarization is fundamental for plant growth and morphogenesis. The polar, cellular localization of Arabidopsis PIN‐FORMED (PIN) proteins is crucial for their function in directional auxin transport. The clustering of PIN polar cargoes within the plasma membrane has been proposed to be important for the maintenance of their polar distribution. However, the more detailed features of PIN clusters and the cellular requirements of cargo clustering remain unclear. Here, we characterized PIN clusters in detail by means of multiple advanced microscopy and quantification methods, such as 3D quantitative imaging or freeze‐fracture replica labeling. The size and aggregation types of PIN clusters were determined by electron microscopy at the nanometer level at different polar domains and at different developmental stages, revealing a strong preference for clustering at the polar domains. Pharmacological and genetic studies revealed that PIN clusters depend on phosphoinositol pathways, cytoskeletal structures and specific cell‐wall components as well as connections between the cell wall and the plasma membrane. This study identifies the role of different cellular processes and structures in polar cargo clustering and provides initial mechanistic insight into the maintenance of polarity in plants and other systems. AU - Li, Hongjiang AU - von Wangenheim, Daniel AU - Zhang, Xixi AU - Tan, Shutang AU - Darwish-Miranda, Nasser AU - Naramoto, Satoshi AU - Wabnik, Krzysztof T AU - de Rycke, Riet AU - Kaufmann, Walter AU - Gütl, Daniel J AU - Tejos, Ricardo AU - Grones, Peter AU - Ke, Meiyu AU - Chen, Xu AU - Dettmer, Jan AU - Friml, Jiří ID - 8582 IS - 1 JF - New Phytologist SN - 0028646X TI - Cellular requirements for PIN polar cargo clustering in Arabidopsis thaliana VL - 229 ER - TY - JOUR AB - Lateral root (LR) formation is an example of a plant post-embryonic organogenesis event. LRs are issued from non-dividing cells entering consecutive steps of formative divisions, proliferation and elongation. The chromatin remodeling protein PICKLE (PKL) negatively regulates auxin-mediated LR formation through a mechanism that is not yet known. Here we show that PKL interacts with RETINOBLASTOMA-RELATED 1 (RBR1) to repress the LATERAL ORGAN BOUNDARIES-DOMAIN 16 (LBD16) promoter activity. Since LBD16 function is required for the formative division of LR founder cells, repression mediated by the PKL–RBR1 complex negatively regulates formative division and LR formation. Inhibition of LR formation by PKL–RBR1 is counteracted by auxin, indicating that, in addition to auxin-mediated transcriptional responses, the fine-tuned process of LR formation is also controlled at the chromatin level in an auxin-signaling dependent manner. AU - Ötvös, Krisztina AU - Miskolczi, Pál AU - Marhavý, Peter AU - Cruz-Ramírez, Alfredo AU - Benková, Eva AU - Robert, Stéphanie AU - Bakó, László ID - 9332 IS - 8 JF - International Journal of Molecular Sciences SN - 1661-6596 TI - Pickle recruits retinoblastoma related 1 to control lateral root formation in arabidopsis VL - 22 ER - TY - JOUR AB - Plants develop new organs to adjust their bodies to dynamic changes in the environment. How independent organs achieve anisotropic shapes and polarities is poorly understood. To address this question, we constructed a mechano-biochemical model for Arabidopsis root meristem growth that integrates biologically plausible principles. Computer model simulations demonstrate how differential growth of neighboring tissues results in the initial symmetry-breaking leading to anisotropic root growth. Furthermore, the root growth feeds back on a polar transport network of the growth regulator auxin. Model, predictions are in close agreement with in vivo patterns of anisotropic growth, auxin distribution, and cell polarity, as well as several root phenotypes caused by chemical, mechanical, or genetic perturbations. Our study demonstrates that the combination of tissue mechanics and polar auxin transport organizes anisotropic root growth and cell polarities during organ outgrowth. Therefore, a mobile auxin signal transported through immobile cells drives polarity and growth mechanics to coordinate complex organ development. AU - Marconi, Marco AU - Gallemi, Marçal AU - Benková, Eva AU - Wabnik, Krzysztof ID - 10270 JF - eLife SN - 2050-084X TI - A coupled mechano-biochemical model for cell polarity guided anisotropic root growth VL - 10 ER - TY - JOUR AB - Plant fitness is largely dependent on the root, the underground organ, which, besides its anchoring function, supplies the plant body with water and all nutrients necessary for growth and development. To exploit the soil effectively, roots must constantly integrate environmental signals and react through adjustment of growth and development. Important components of the root management strategy involve a rapid modulation of the root growth kinetics and growth direction, as well as an increase of the root system radius through formation of lateral roots (LRs). At the molecular level, such a fascinating growth and developmental flexibility of root organ requires regulatory networks that guarantee stability of the developmental program but also allows integration of various environmental inputs. The plant hormone auxin is one of the principal endogenous regulators of root system architecture by controlling primary root growth and formation of LR. In this review, we discuss recent progress in understanding molecular networks where auxin is one of the main players shaping the root system and acting as mediator between endogenous cues and environmental factors. AU - Cavallari, Nicola AU - Artner, Christina AU - Benková, Eva ID - 9212 IS - 7 JF - Cold Spring Harbor Perspectives in Biology SN - 1943-0264 TI - Auxin-regulated lateral root organogenesis VL - 13 ER - TY - JOUR AB - Size control is a fundamental question in biology, showing incremental complexity in plants, whose cells possess a rigid cell wall. The phytohormone auxin is a vital growth regulator with central importance for differential growth control. Our results indicate that auxin-reliant growth programs affect the molecular complexity of xyloglucans, the major type of cell wall hemicellulose in eudicots. Auxin-dependent induction and repression of growth coincide with reduced and enhanced molecular complexity of xyloglucans, respectively. In agreement with a proposed function in growth control, genetic interference with xyloglucan side decorations distinctly modulates auxin-dependent differential growth rates. Our work proposes that auxin-dependent growth programs have a spatially defined effect on xyloglucan’s molecular structure, which in turn affects cell wall mechanics and specifies differential, gravitropic hypocotyl growth. AU - Velasquez, Silvia Melina AU - Guo, Xiaoyuan AU - Gallemi, Marçal AU - Aryal, Bibek AU - Venhuizen, Peter AU - Barbez, Elke AU - Dünser, Kai Alexander AU - Darino, Martin AU - Pӗnčík, Aleš AU - Novák, Ondřej AU - Kalyna, Maria AU - Mouille, Gregory AU - Benková, Eva AU - Bhalerao, Rishikesh P. AU - Mravec, Jozef AU - Kleine-Vehn, Jürgen ID - 9986 IS - 17 JF - International Journal of Molecular Sciences KW - auxin KW - growth KW - cell wall KW - xyloglucans KW - hypocotyls KW - gravitropism SN - 1661-6596 TI - Xyloglucan remodeling defines auxin-dependent differential tissue expansion in plants VL - 22 ER - TY - JOUR AB - Clathrin-mediated endocytosis is the major route of entry of cargos into cells and thus underpins many physiological processes. During endocytosis, an area of flat membrane is remodeled by proteins to create a spherical vesicle against intracellular forces. The protein machinery which mediates this membrane bending in plants is unknown. However, it is known that plant endocytosis is actin independent, thus indicating that plants utilize a unique mechanism to mediate membrane bending against high-turgor pressure compared to other model systems. Here, we investigate the TPLATE complex, a plant-specific endocytosis protein complex. It has been thought to function as a classical adaptor functioning underneath the clathrin coat. However, by using biochemical and advanced live microscopy approaches, we found that TPLATE is peripherally associated with clathrin-coated vesicles and localizes at the rim of endocytosis events. As this localization is more fitting to the protein machinery involved in membrane bending during endocytosis, we examined cells in which the TPLATE complex was disrupted and found that the clathrin structures present as flat patches. This suggests a requirement of the TPLATE complex for membrane bending during plant clathrin–mediated endocytosis. Next, we used in vitro biophysical assays to confirm that the TPLATE complex possesses protein domains with intrinsic membrane remodeling activity. These results redefine the role of the TPLATE complex and implicate it as a key component of the evolutionarily distinct plant endocytosis mechanism, which mediates endocytic membrane bending against the high-turgor pressure in plant cells. AU - Johnson, Alexander J AU - Dahhan, Dana A AU - Gnyliukh, Nataliia AU - Kaufmann, Walter AU - Zheden, Vanessa AU - Costanzo, Tommaso AU - Mahou, Pierre AU - Hrtyan, Mónika AU - Wang, Jie AU - Aguilera Servin, Juan L AU - van Damme, Daniël AU - Beaurepaire, Emmanuel AU - Loose, Martin AU - Bednarek, Sebastian Y AU - Friml, Jiří ID - 9887 IS - 51 JF - Proceedings of the National Academy of Sciences TI - The TPLATE complex mediates membrane bending during plant clathrin-mediated endocytosis VL - 118 ER - TY - JOUR AB - Availability of the essential macronutrient nitrogen in soil plays a critical role in plant growth, development, and impacts agricultural productivity. Plants have evolved different strategies for sensing and responding to heterogeneous nitrogen distribution. Modulation of root system architecture, including primary root growth and branching, is among the most essential plant adaptions to ensure adequate nitrogen acquisition. However, the immediate molecular pathways coordinating the adjustment of root growth in response to distinct nitrogen sources, such as nitrate or ammonium, are poorly understood. Here, we show that growth as manifested by cell division and elongation is synchronized by coordinated auxin flux between two adjacent outer tissue layers of the root. This coordination is achieved by nitrate‐dependent dephosphorylation of the PIN2 auxin efflux carrier at a previously uncharacterized phosphorylation site, leading to subsequent PIN2 lateralization and thereby regulating auxin flow between adjacent tissues. A dynamic computer model based on our experimental data successfully recapitulates experimental observations. Our study provides mechanistic insights broadening our understanding of root growth mechanisms in dynamic environments. AU - Ötvös, Krisztina AU - Marconi, Marco AU - Vega, Andrea AU - O’Brien, Jose AU - Johnson, Alexander J AU - Abualia, Rashed AU - Antonielli, Livio AU - Montesinos López, Juan C AU - Zhang, Yuzhou AU - Tan, Shutang AU - Cuesta, Candela AU - Artner, Christina AU - Bouguyon, Eleonore AU - Gojon, Alain AU - Friml, Jiří AU - Gutiérrez, Rodrigo A. AU - Wabnik, Krzysztof T AU - Benková, Eva ID - 9010 IS - 3 JF - EMBO Journal SN - 02614189 TI - Modulation of plant root growth by nitrogen source-defined regulation of polar auxin transport VL - 40 ER - TY - JOUR AB - Nitrate commands genome-wide gene expression changes that impact metabolism, physiology, plant growth, and development. In an effort to identify new components involved in nitrate responses in plants, we analyze the Arabidopsis thaliana root phosphoproteome in response to nitrate treatments via liquid chromatography coupled to tandem mass spectrometry. 176 phosphoproteins show significant changes at 5 or 20 min after nitrate treatments. Proteins identified by 5 min include signaling components such as kinases or transcription factors. In contrast, by 20 min, proteins identified were associated with transporter activity or hormone metabolism functions, among others. The phosphorylation profile of NITRATE TRANSPORTER 1.1 (NRT1.1) mutant plants was significantly altered as compared to wild-type plants, confirming its key role in nitrate signaling pathways that involves phosphorylation changes. Integrative bioinformatics analysis highlights auxin transport as an important mechanism modulated by nitrate signaling at the post-translational level. We validated a new phosphorylation site in PIN2 and provide evidence that it functions in primary and lateral root growth responses to nitrate. AU - Vega, Andrea AU - Fredes, Isabel AU - O’Brien, José AU - Shen, Zhouxin AU - Ötvös, Krisztina AU - Abualia, Rashed AU - Benková, Eva AU - Briggs, Steven P. AU - Gutiérrez, Rodrigo A. ID - 9913 IS - 9 JF - EMBO Reports SN - 1469-221X TI - Nitrate triggered phosphoproteome changes and a PIN2 phosphosite modulating root system architecture VL - 22 ER - TY - THES AB - Nitrogen is an essential macronutrient determining plant growth, development and affecting agricultural productivity. Root, as a hub that perceives and integrates local and systemic signals on the plant’s external and endogenous nitrogen resources, communicates with other plant organs to consolidate their physiology and development in accordance with actual nitrogen balance. Over the last years, numerous studies demonstrated that these comprehensive developmental adaptations rely on the interaction between pathways controlling nitrogen homeostasis and hormonal networks acting globally in the plant body. However, molecular insights into how the information about the nitrogen status is translated through hormonal pathways into specific developmental output are lacking. In my work, I addressed so far poorly understood mechanisms underlying root-to-shoot communication that lead to a rapid re-adjustment of shoot growth and development after nitrate provision. Applying a combination of molecular, cell, and developmental biology approaches, genetics and grafting experiments as well as hormonal analytics, I identified and characterized an unknown molecular framework orchestrating shoot development with a root nitrate sensory system. AU - Abualia, Rashed ID - 10303 SN - 2663-337X TI - Role of hormones in nitrate regulated growth ER - TY - THES AB - Plants maintain the capacity to develop new organs e.g. lateral roots post-embryonically throughout their whole life and thereby flexibly adapt to ever-changing environmental conditions. Plant hormones auxin and cytokinin are the main regulators of the lateral root organogenesis. Additionally to their solo activities, the interaction between auxin and cytokinin plays crucial role in fine-tuning of lateral root development and growth. In particular, cytokinin modulates auxin distribution within the developing lateral root by affecting the endomembrane trafficking of auxin transporter PIN1 and promoting its vacuolar degradation (Marhavý et al., 2011, 2014). This effect is independent of transcription and translation. Therefore, it suggests novel, non-canonical cytokinin activity occuring possibly on the posttranslational level. Impact of cytokinin and other plant hormones on auxin transporters (including PIN1) on the posttranslational level is described in detail in the introduction part of this thesis in a form of a review (Semeradova et al., 2020). To gain insights into the molecular machinery underlying cytokinin effect on the endomembrane trafficking in the plant cell, in particular on the PIN1 degradation, we conducted two large proteomic screens: 1) Identification of cytokinin binding proteins using chemical proteomics. 2) Monitoring of proteomic and phosphoproteomic changes upon cytokinin treatment. In the first screen, we identified DYNAMIN RELATED PROTEIN 2A (DRP2A). We found that DRP2A plays a role in cytokinin regulated processes during the plant growth and that cytokinin treatment promotes destabilization of DRP2A protein. However, the role of DRP2A in the PIN1 degradation remains to be elucidated. In the second screen, we found VACUOLAR PROTEIN SORTING 9A (VPS9A). VPS9a plays crucial role in plant’s response to cytokin and in cytokinin mediated PIN1 degradation. Altogether, we identified proteins, which bind to cytokinin and proteins that in response to cytokinin exhibit significantly changed abundance or phosphorylation pattern. By combining information from these two screens, we can pave our way towards understanding of noncanonical cytokinin effects. AU - Semerádová, Hana ID - 10135 SN - 2663-337X TI - Molecular mechanisms of the cytokinin-regulated endomembrane trafficking to coordinate plant organogenesis ER - TY - JOUR AB - The ability to sense environmental temperature and to coordinate growth and development accordingly, is critical to the reproductive success of plants. Flowering time is regulated at the level of gene expression by a complex network of factors that integrate environmental and developmental cues. One of the main players, involved in modulating flowering time in response to changes in ambient temperature is FLOWERING LOCUS M (FLM). FLM transcripts can undergo extensive alternative splicing producing multiple variants, of which FLM-β and FLM-δ are the most representative. While FLM-β codes for the flowering repressor FLM protein, translation of FLM-δ has the opposite effect on flowering. Here we show that the cyclin-dependent kinase G2 (CDKG2), together with its cognate cyclin, CYCLYN L1 (CYCL1) affects the alternative splicing of FLM, balancing the levels of FLM-β and FLM-δ across the ambient temperature range. In the absence of the CDKG2/CYCL1 complex, FLM-β expression is reduced while FLM-δ is increased in a temperature dependent manner and these changes are associated with an early flowering phenotype in the cdkg2 mutant lines. In addition, we found that transcript variants retaining the full FLM intron 1 are sequestered in the cell nucleus. Strikingly, FLM intron 1 splicing is also regulated by CDKG2/CYCL1. Our results provide evidence that temperature and CDKs regulate the alternative splicing of FLM, contributing to flowering time definition. AU - Nibau, Candida AU - Gallemi, Marçal AU - Dadarou, Despoina AU - Doonan, John H. AU - Cavallari, Nicola ID - 7350 JF - Frontiers in Plant Science SN - 1664-462X TI - Thermo-sensitive alternative splicing of FLOWERING LOCUS M is modulated by cyclin-dependent kinase G2 VL - 10 ER - TY - JOUR AB - Plants as non-mobile organisms constantly integrate varying environmental signals to flexibly adapt their growth and development. Local fluctuations in water and nutrient availability, sudden changes in temperature or other abiotic and biotic stresses can trigger changes in the growth of plant organs. Multiple mutually interconnected hormonal signaling cascades act as essential endogenous translators of these exogenous signals in the adaptive responses of plants. Although the molecular backbones of hormone transduction pathways have been identified, the mechanisms underlying their interactions are largely unknown. Here, using genome wide transcriptome profiling we identify an auxin and cytokinin cross-talk component; SYNERGISTIC ON AUXIN AND CYTOKININ 1 (SYAC1), whose expression in roots is strictly dependent on both of these hormonal pathways. We show that SYAC1 is a regulator of secretory pathway, whose enhanced activity interferes with deposition of cell wall components and can fine-tune organ growth and sensitivity to soil pathogens. AU - Hurny, Andrej AU - Cuesta, Candela AU - Cavallari, Nicola AU - Ötvös, Krisztina AU - Duclercq, Jerome AU - Dokládal, Ladislav AU - Montesinos López, Juan C AU - Gallemi, Marçal AU - Semeradova, Hana AU - Rauter, Thomas AU - Stenzel, Irene AU - Persiau, Geert AU - Benade, Freia AU - Bhalearo, Rishikesh AU - Sýkorová, Eva AU - Gorzsás, András AU - Sechet, Julien AU - Mouille, Gregory AU - Heilmann, Ingo AU - De Jaeger, Geert AU - Ludwig-Müller, Jutta AU - Benková, Eva ID - 7805 JF - Nature Communications TI - Synergistic on Auxin and Cytokinin 1 positively regulates growth and attenuates soil pathogen resistance VL - 11 ER - TY - JOUR AB - In agricultural systems, nitrate is the main source of nitrogen available for plants. Besides its role as a nutrient, nitrate has been shown to act as a signal molecule for plant growth, development and stress responses. In Arabidopsis, the NRT1.1 nitrate transceptor represses lateral root (LR) development at low nitrate availability by promoting auxin basipetal transport out of the LR primordia (LRPs). In addition, our present study shows that NRT1.1 acts as a negative regulator of the TAR2 auxin biosynthetic gene expression in the root stele. This is expected to repress local auxin biosynthesis and thus to reduce acropetal auxin supply to the LRPs. Moreover, NRT1.1 also negatively affects expression of the LAX3 auxin influx carrier, thus preventing cell wall remodeling required for overlying tissues separation during LRP emergence. Both NRT1.1-mediated repression of TAR2 and LAX3 are suppressed at high nitrate availability, resulting in the nitrate induction of TAR2 and LAX3 expression that is required for optimal stimulation of LR development by nitrate. Altogether, our results indicate that the NRT1.1 transceptor coordinately controls several crucial auxin-associated processes required for LRP development, and as a consequence that NRT1.1 plays a much more integrated role than previously anticipated in regulating the nitrate response of root system architecture. AU - Maghiaoui, A AU - Bouguyon, E AU - Cuesta, Candela AU - Perrine-Walker, F AU - Alcon, C AU - Krouk, G AU - Benková, Eva AU - Nacry, P AU - Gojon, A AU - Bach, L ID - 7948 IS - 15 JF - Journal of Experimental Botany SN - 0022-0957 TI - The Arabidopsis NRT1.1 transceptor coordinately controls auxin biosynthesis and transport to regulate root branching in response to nitrate VL - 71 ER - TY - JOUR AB - Plant hormone cytokinins are perceived by a subfamily of sensor histidine kinases (HKs), which via a two-component phosphorelay cascade activate transcriptional responses in the nucleus. Subcellular localization of the receptors proposed the endoplasmic reticulum (ER) membrane as a principal cytokinin perception site, while study of cytokinin transport pointed to the plasma membrane (PM)-mediated cytokinin signalling. Here, by detailed monitoring of subcellular localizations of the fluorescently labelled natural cytokinin probe and the receptor ARABIDOPSIS HISTIDINE KINASE 4 (CRE1/AHK4) fused to GFP reporter, we show that pools of the ER-located cytokinin receptors can enter the secretory pathway and reach the PM in cells of the root apical meristem, and the cell plate of dividing meristematic cells. Brefeldin A (BFA) experiments revealed vesicular recycling of the receptor and its accumulation in BFA compartments. We provide a revised view on cytokinin signalling and the possibility of multiple sites of perception at PM and ER. AU - Kubiasova, Karolina AU - Montesinos López, Juan C AU - Šamajová, Olga AU - Nisler, Jaroslav AU - Mik, Václav AU - Semeradova, Hana AU - Plíhalová, Lucie AU - Novák, Ondřej AU - Marhavý, Peter AU - Cavallari, Nicola AU - Zalabák, David AU - Berka, Karel AU - Doležal, Karel AU - Galuszka, Petr AU - Šamaj, Jozef AU - Strnad, Miroslav AU - Benková, Eva AU - Plíhal, Ondřej AU - Spíchal, Lukáš ID - 8336 JF - Nature Communications TI - Cytokinin fluoroprobe reveals multiple sites of cytokinin perception at plasma membrane and endoplasmic reticulum VL - 11 ER -