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  • lateral auxin
  • By employing a quantitative cell biological approach, we demonstrate that flavonoids partially restore the formation of lateral auxin gradients in the absence of PIN2. (ugent.be)
  • asymmetric
  • We propose that flavonoids promote asymmetric PIN shifts during gravity stimulation, thus redirecting basipetal auxin streams necessary for root bending. (ugent.be)
  • role of auxin
  • From these studies it will be apparent that we still do not have a clear understanding of the exact role of auxin in the process of adventitious root initiation. (springer.com)
  • Scientists from the Centre for Organismal Studies (Germany), Gregor Mendel Institute (Austria), Institute of Cytology and Genetics (Russia), Novosibirsk State University (Russia), Wageningen University (Netherlands) and Institute for Plant Molecular and Cellular Biology, Polytechnic University of Valencia (Spain) showed a key role of auxin response regulatory proteins in the cambium (the stem cell niche responsible for wood formation, and also for specified spatial coordination features of gene activity. (eurekalert.org)
  • The role of auxin in regulating cell expansion in intact plants is somewhat less clear, however, because application of exogenous auxin often does not stimulate elongation. (pnas.org)
  • This study uses a novel technique of transiently applying a polar auxin transport inhibitor, N-1-naphthylphthalamic acid (NPA), to developing Arabidopsis flowers to further characterize the role of auxin in organogenesis. (biologists.org)
  • concentrations
  • at low auxin concentrations, auxin transported/time similar with or without ethylene treatment. (iastate.edu)
  • Recent studies show that plant organ positioning may be mediated by localized concentrations of the plant hormone auxin. (pnas.org)
  • We also optimize parameter values for the PIN1 dynamics by using a detailed auxin transport model, for which parameter values are taken from experimental estimates, together with a template consisting of cell and wall compartments as well as PIN1 concentrations quantitatively extracted from confocal data. (pnas.org)
  • A, Inhibition of root elongation by increasing concentrations of the synthetic auxin 2,4-D. Five-day-old seedlings grown on ATS were transferred to medium containing 2,4-D and grown three additional days ( n = 10). (nih.gov)
  • However, at high cellular auxin concentrations, auxin binds to an intracellular nuclear receptor complex (SCR-TIR1/AFB), a ubiquitin ligase that can only efficiently bind its substrate proteins in the presence of the hormone. (wur.nl)
  • In this project, we will use Marchantia polymorpha and experimentally determine protein concentrations, protein turnover rates, dissociation constants of protein interactions and binding rates of MpARFs to auxin responsive element (e.g. (wur.nl)
  • In addition, application of different concentrations of NPA reveal an increased sensitivity of weak ettin alleles to disruptions in polar auxin transport. (biologists.org)
  • However, auxin analysis has been challenging because auxins typically occur at low concentrations, while compounds that interfere with their detection often occur at high concentrations, in plant tissues. (mdpi.com)
  • proteins
  • During their investigations, they revealed that the key gene coordinating stem cells, WOX4, is controlled by the vital plant hormone auxin via auxin response proteins. (eurekalert.org)
  • The auxin-bound receptor recognizes Aux/IAAs proteins for ubiquitination and degradation, which serves as a transcriptional switch of ARF transcriptional repression thereby allowing auxin regulated gene transcription. (wur.nl)
  • At very low auxin levels (a), the auxin response factors (ARFs, in blue) are kept inactive by the Aux/IAA proteins (in red) through heterodimerization. (wur.nl)
  • While the function of the individual proteins of the auxin network is well understood, a major unanswered question is how the interactions among those proteins generate a dynamic response system with different outputs. (wur.nl)
  • Marchantia polymorpha has only a single auxin receptor TIR1/AFB (MpTIR1), a single AUX/IAA (MpIAA) inhibitor protein, and three ARF proteins (MpARF1, MpARF2, and MpARF3). (wur.nl)
  • Having this limited number of response proteins in Marchantia makes it possibly the best model system for a quantitative study of auxin response protein network. (wur.nl)
  • Polar cell-to-cell auxin transport is mediated by carrier proteins of the AUX1 (Auxin resistant 1), LAX (like-AUX1), PGP (Phospho-glycoprotein) and PIN (pin-formed) families . (plos.org)
  • The asymmetric localization of the plasma membrane-localized PIN proteins determines the direction of inter-cellular auxin flow . (plos.org)
  • elongation
  • Based on these results, we propose that growth at high temperature promotes an increase in auxin levels resulting in increased hypocotyl elongation. (pnas.org)
  • The ability of exogenous auxin to promote cell elongation in excised stem and hypocotyl segments has been studied extensively ( 9 ). (pnas.org)
  • The inability of exogenous auxin to stimulate prolonged cell expansion led to the suggestion that auxin plays little if any role in regulating plant growth by cell elongation ( 10 ). (pnas.org)
  • In addition to enhancing the auxin response defects of tir1-1, iar4 single mutants exhibit numerous auxin-related phenotypes including auxin-resistant root growth and reduced lateral root development, as well as defects in primary root growth, root hair initiation, and root hair elongation. (nih.gov)
  • The plant hormone auxin is involved in embryogenesis, organogenesis, vascular tissue differentiation, and hypocotyl and root elongation, as well as growth responses to environmental stimuli. (plos.org)
  • Cytokinin treatment also inhibited rapid auxin responses in hypocotyl segments: auxin-stimulated elongation, H(+) secretion, and ethylene synthesis were all inhibited by cytokinin in wild-type hypocotyl segments, and thus mimicked the impaired auxin responsiveness found in dgt hypocotyls. (rti.org)
  • Regulation
  • Cambium activity has been tightly associated with the plant hormone auxin for a long time, but at the level of gene regulation (the «reading» of the genetic information), the process was studied with such a high accuracy for the first time. (eurekalert.org)
  • We also describe experimental data indicating that auxin-RAC/ROP crosstalk may form regulatory feedback loops and theoretical modeling that attempts to connect local auxin gradients with RAC/ROP regulation of cell polarity. (plantcell.org)
  • These biochemical properties of the RAC/ROP switch enable the regulation of their function by external signals such as auxin. (plantcell.org)
  • regulates auxin
  • Furthermore, we detect a corresponding increase in the level of free IAA in seedlings grown at high temperature, suggesting that temperature regulates auxin synthesis or catabolism to mediate this growth response. (pnas.org)
  • processes
  • This book highlights topics ranging from physiological and genetic studies of polar auxin transport in plant development, to growth responses to the environment and plant-microbe interactions, to hormonal cross-talks with various cellular and molecular regulatory processes essential for polar auxin transport. (springer.com)
  • Written and edited by experts in the field, this collection from Cold Spring Harbor Perspectives in Biology describes the numerous processes auxin controls. (cshlpress.com)
  • PIN6 is auxin-inducible and is expressed during multiple auxin-regulated developmental processes. (plos.org)
  • metabolism
  • It will be not possible in this review paper to describe all the work on auxin application, transport and metabolism that might be relevant to studies of adventitious root initiation. (springer.com)
  • Asymmetric
  • Asymmetric auxin distribution is instrumental for the differential growth that causes organ bending on tropic stimuli and curvatures during plant development. (pnas.org)
  • These transporters are able to be redistributed between cell faces, causing the asymmetric auxin transport that is a key requirement for the formation of vein patterns in leaves. (uleth.ca)
  • transport
  • Polarity (direction) of auxin transport is independent of orientation of plant with respect to gravity. (iastate.edu)
  • a cotton defoliant, used to get cotton plants to drop green leaves prematurely for easier harvest of cotton bolls) increases ethylene synthesis and therefore inhibits auxin transport. (iastate.edu)
  • Maybe when ethylene is synthesized during senescence, ripening or leaf abscission, this ethylene also inhibits auxin transport. (iastate.edu)
  • Decreased auxin transport in inflorescences. (iastate.edu)
  • Mitogen-activated protein kinase (MAPK) is modulated by auxin and the protein kinase PINOID has a role in auxin transport modulation even though their functional linkage to other signalling molecules is ill-defined. (springer.com)
  • Auxin is present in all plant phyla, and the existence of polar auxin transport (PAT) is well established in land plants. (mdpi.com)
  • In the study of auxin function, transport and its evolution, the algae form an interesting research target. (mdpi.com)
  • Recently, proof for polar auxin transport in Chara species was published and auxin related research in algae gained more attention. (mdpi.com)
  • In this review we discuss auxin transport in algae with respect to land plants and suggest directions for future studies. (mdpi.com)
  • Physiological studies in the decades since have demonstrated that auxin is unidirectionally transported in plants, a process dubbed polar auxin transport. (springer.com)
  • Remarkably, components of the polar auxin transport machinery are present in both lower plants such as mosses and higher plants including monocots and eudicots, illustrating the key role of polar auxin transport in plant evolution. (springer.com)
  • Auxin transport inhibitor naphthylphthalamic acid can attenuate canker development of sweet orange infected by Xanthomonas axonopodis pv. (frontiersin.org)
  • Type-A and type-B arr mutant branching phenotypes are associated with altered auxin transport. (plantphysiol.org)
  • These changes in auxin-regulated growth correlated with a reduction in total auxin transport as well as with an altered activity of DR5-GUS auxin response reporter. (plos.org)
  • To further investigate the interplay between LFY and auxin during flower development, we examined the phenotypic consequence of disrupting polar auxin transport in lfy mutants by genetic means. (mdpi.com)
  • Plants with compromised LFY activity exhibit increased sensitivity to disruption of polar auxin transport. (mdpi.com)
  • Compromised polar auxin transport activity in the lfy mutant background resulted in formation of fewer floral organs, abnormal gynoecium development, and fused sepals. (mdpi.com)
  • cellular
  • We show that such a model is sufficient to create regular spatial patterns of auxin concentration on systems with static and dynamic cellular connectivities, the latter governed by a mechanical model. (pnas.org)
  • transcription
  • We identify the auxin-dependent transcription factor ARF5/MONOPTEROS to cell-autonomously restrict the number of stem cells by directly attenuating the activity of the stem cell-promoting WOX4 gene. (wur.nl)
  • NPA's effects on gynoecium patterning mimic the phenotype of mutations in ETTIN, a member of the auxin response factor family of transcription factors. (biologists.org)
  • growth
  • Brassinosteroids, auxin, and gibberellins (GAs) promote hypocotyl growth, whereas cytokinins and abscisic acid (ABA) have growth inhibitory effects ( 3 - 7 ). (pnas.org)
  • This strong growth-promoting property of auxin provided the basis for its identification as the first known plant hormone by Went nearly 70 years ago. (pnas.org)
  • Auxin is a plant hormone required for the establishment of growth orientation. (pnas.org)
  • The importance of the plant growth regulator auxin for plant growth has long been recognized, even before the discovery of its chemical structures in the early 20th century. (springer.com)
  • Auxin functions as a key morphogen in regulating plant growth and development. (plantcell.org)
  • Auxins are key hormones in the control of many aspects of plant growth and development and their endogenous levels are considered critical in the process of adventitious root induction. (mdpi.com)
  • These tissues were treated with the plant growth regulator 2,4-dichlorophenoxyacetic acid (2,4-D), an auxin analogue, or abscisic acid (ABA), and the cytosolic pH (pHcyt) and cytosolic Ca2+ ([Ca2+]cyt) changes were monitored by confocal scanning optical microscopy. (pnas.org)
  • plants
  • Firstly, using transgenic plants the authors detected auxin response signal in the xylem-associated cambium. (eurekalert.org)
  • In higher plants, auxin is generated in apical plant parts and transported from cell-to-cell in a polar fashion. (mdpi.com)
  • This review focuses on the phenomena and the possible mechanisms of auxin in the interactions of plants and non-gall- or tumor-inducing pathogens. (frontiersin.org)
  • Auxin can promote disease symptoms in many plants. (frontiersin.org)
  • PIN1
  • However, the question of what signals determine PIN1 polarization and how this gives rise to regular patterns of auxin concentration remains unknown. (pnas.org)
  • exogenous
  • Exogenous auxins are used extensively in the clonal propagation of tree species by cuttings or tissue culture. (mdpi.com)
  • quantification
  • Understanding of auxin effects has advanced with the development of increasingly accurate methods for auxin quantification. (mdpi.com)
  • Interference from other compounds has been addressed by extensive purification of plant extracts prior to auxin analysis, although this means that quantification methods have been limited by their expense. (mdpi.com)
  • This review explores the extraction, purification, and quantification of auxins and the application of these techniques in developing improved methods for the clonal propagation of forestry trees. (mdpi.com)
  • Zuffellato-Ribas, K.C. The Use of Auxin Quantification for Understanding Clonal Tree Propagation. (mdpi.com)
  • mechanisms
  • The book also examines the extraordinary complexity of auxin responses and discusses new computational models for mechanisms that allow this hormone to generate such a wide variety of outputs. (cshlpress.com)
  • Many aspects of plant development are regulated by antagonistic interactions between the plant hormones auxin and cytokinin, but the molecular mechanisms of this interaction are not understood. (rti.org)
  • Several plant hormones, prominent among them auxin, have been implicated in the acquisition of founder cell identity by differentiated cells, but the mechanisms underlying this process are largely elusive. (nih.gov)
  • concentration
  • We conclude that auxin must be within a specific concentration range for its correct distribution, and this range is maintained by auxin methylation in the endodermis, the cell type that perceives gravity. (pnas.org)
  • Increased auxin concentration in the nucleus (b), recruits Aux/IAAs forming a complex with SCF (TIR/AFBs) (in green). (wur.nl)
  • thus
  • Thus, auxin is the local instructive signal that is sufficient for acquisition of founder cell identity and can be considered a morphogenetic trigger in postembryonic plant organogenesis. (nih.gov)
  • spatial
  • The cambium, the stem cell niche mediating wood formation, fundamentally depends on auxin signalling but its exact role and spatial organization is obscure. (wur.nl)
  • lateral root
  • Auxin acts as a local morphogenetic trigger to specify lateral root founder cells. (nih.gov)
  • Here, we show that auxin and its local accumulation in root pericycle cells is a necessary and sufficient signal to respecify these cells into lateral root founder cells. (nih.gov)
  • Accordingly, local activation of auxin response correlates absolutely with the acquisition of founder cell identity and precedes the actual formation of a lateral root primordium through patterned cell division. (nih.gov)
  • Auxin response-marked specification of lateral root founder cells precedes cell cycle activation in the pericycle. (nih.gov)
  • MONOPTEROS
  • Our recent study revealed that LFY additionally acts downstream of AUXIN RESPONSE FACTOR5/MONOPTEROS to promote flower primordium initiation. (mdpi.com)
  • putative
  • In a screen for enhancers of tir1-1 auxin resistance, we identified two novel alleles of the putative mitochondrial pyruvate dehydrogenase E1alpha-subunit, IAA-Alanine Resistant4 (IAR4). (nih.gov)