TY - GEN A1 - Prát, Tomáš A1 - Hajny ́, Jakub A1 - Grunewald, Wim A1 - Vasileva, Mina A1 - Molnár, Gergely A1 - Tejos, Ricardo A1 - Schmid, Markus A1 - Sauer, Michael A1 - Friml, Jiří T1 - WRKY23 is a component of the transcriptional network mediating auxin feedback on PIN polarity T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Auxin is unique among plant hormones due to its directional transport that is mediated by the polarly distributed PIN auxin transporters at the plasma membrane. The canalization hypothesis proposes that the auxin feedback on its polar flow is a crucial, plant-specific mechanism mediating multiple self-organizing developmental processes. Here, we used the auxin effect on the PIN polar localization in Arabidopsis thaliana roots as a proxy for the auxin feedback on the PIN polarity during canalization. We performed microarray experiments to find regulators of this process that act downstream of auxin. We identified genes that were transcriptionally regulated by auxin in an AXR3/IAA17-and ARF7/ARF19-dependent manner. Besides the known components of the PIN polarity, such as PID and PIP5K kinases, a number of potential new regulators were detected, among which the WRKY23 transcription factor, which was characterized in more detail. Gain-and loss-of-function mutants confirmed a role for WRKY23 in mediating the auxin effect on the PIN polarity. Accordingly, processes requiring auxin-mediated PIN polarity rearrangements, such as vascular tissue development during leaf venation, showed a higher WRKY23 expression and required the WRKY23 activity. Our results provide initial insights into the auxin transcriptional network acting upstream of PIN polarization and, potentially, canalization-mediated plant development. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1123 KW - apical-basal axis KW - arabidopsis-thaliana KW - root gravitropism KW - DNA-binding KW - gene-expression KW - transport KW - efflux KW - canalization KW - plants KW - phosphorylation Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-446331 SN - 1866-8372 IS - 1123 ER - TY - JOUR A1 - Lecourieux, Fatma A1 - Kappel, Christian A1 - Lecourieux, David A1 - Serrano, Alejandra A1 - Torres, Elizabeth A1 - Arce-Johnson, Patricio A1 - Delrot, Serge T1 - An update on sugar transport and signalling in grapevine JF - Journal of experimental botany N2 - In addition to their role as a source of reduced carbon, sugars may directly or indirectly control a wide range of activities in plant cells, through transcriptional and post-translational regulation. This control has been studied in detail using Arabidopsis thaliana, where genetic analysis offers many possibilities. Much less is known about perennial woody species. For several years, various aspects of sugar sensing and signalling have been investigated in the grape (Vitis vinifera L.) berry, an organ that accumulates high concentrations of hexoses in the vacuoles of flesh cells. Here we review various aspects of this topic: the molecular basis of sugar transport and its regulation by sugars in grapevine; the functional analysis of several sugar-induced genes; the effects of some biotic and abiotic stresses on the sugar content of the berry; and finally the effects of exogenous sugar supply on the ripening process in field conditions. A picture of complex feedback and multiprocess regulation emerges from these data. KW - Fruit biology KW - grapevine KW - signalling KW - stress KW - sugar KW - transport Y1 - 2014 U6 - https://doi.org/10.1093/jxb/ert394 SN - 0022-0957 SN - 1460-2431 VL - 65 IS - 3 SP - 821 EP - 832 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Lucia Gomez-Porras, Judith A1 - Mauricio Riano-Pachon, Diego A1 - Benito, Begona A1 - Haro, Rosario A1 - Sklodowski, Kamil A1 - Rodriguez-Navarro, Alonso A1 - Dreyer, Ingo T1 - Phylogenetic analysis of K+ transporters in bryophytes, lycophytes, and flowering plants indicates a specialization of vascular plants JF - Frontiers in plant science N2 - As heritage from early evolution, potassium (K+) is absolutely necessary for all living cells. It plays significant roles as stabilizer in metabolism and is important for enzyme activation, stabilization of protein synthesis, and neutralization of negative charges on cellular molecules as proteins and nucleic acids. Land plants even enlarged this spectrum of K+ utilization after having gone ashore, despite the fact that K+ is far less available in their new oligotrophic habitats than in sea water. Inevitably, plant cells had to improve and to develop unique transport systems for K+ accumulation and distribution. In the past two decades a manifold of K+ transporters from flowering plants has been identified at the molecular level. The recently published genome of the fern ally Selaginella moellendorffii now helps in providing a better understanding on the molecular changes involved in the colonization of land and the development of the vasculature and the seeds. In this article we present an inventory of K+ transporters of this lycophyte and pigeonhole them together with their relatives from the moss Physcomitrella patens, the monocotyledon Oryza sativa, and two dicotyledonous species, the herbaceous plant Arabidopsis thaliana, and the tree Populus trichocarpa. Interestingly, the transition of green plants from an aqueous to a dry environment coincides with a dramatic reduction in the diversity of voltage-gated potassium channels followed by a diversification on the basis of one surviving K+ channel class. The first appearance of K+ release (K-out) channels in S. moellendorffii that were shown in Arabidopsis to be involved in xylem loading and guard cell closure coincides with the specialization of vascular plants and may indicate an important adaptive step. KW - potassium KW - transport KW - channel KW - voltage-dependent KW - voltage-independent KW - high-affinity KW - Selaginella Y1 - 2012 U6 - https://doi.org/10.3389/fpls.2012.00167 SN - 1664-462X VL - 3 PB - Frontiers Research Foundation CY - Lausanne ER - TY - THES A1 - Beeg, Janina T1 - Cooperative behavior of motor proteins T1 - Transportverhalten kollektiv arbeitender Motorproteine N2 - The cytoskeletal motor protein kinesin-1 (conventional kinesin) is the fast carrier for intracellular cargo transport along microtubules. So far most studies aimed at investigating the transport properties of individual motor molecules. However, the transport in cells usually involves the collective work of more than one motor. In the present work, we have studied the movement of beads as artificial loads/organelles pulled by several kinesin-1 motors in vitro. For a wide range of motor coverage of the beads and different bead (cargo) sizes the transport parameters walking distance or run length, velocity and force generation are measured. The results indicate that the transport parameters are influenced by the number of motors carrying the bead. While the transport velocity slightly decreases, an increase in the run length was measured and higher forces are determined, when more motors are involved. The effective number of motors pulling a bead is estimated by measuring the change in the hydrodynamic diameter of kinesin-coated beads using dynamic light scattering. The geometrical constraints imposed by the transport system have been taken into account. Thus, results for beads of different size and motor-surface coverage could be compared. In addition, run length-distributions obtained for the smallest bead size were matched to theoretically calculated distributions. The latter yielded an average number of pulling motors, which is in agreement with the effective motor numbers determined experimentally. N2 - Kinesin-1 (konventionelles Kinesin) ist ein Motorprotein des Zytoskeletts, das für den schnellen intrazellulären Lastentransport auf Mikrotubuli verantwortlich ist. Das Hauptinteresse vieler Studien lag bisher auf der Erforschung der Transporteigenschaften von Einzelmotormolekülen. Der Transport in der Zelle erfordert aber gewöhnlich kollektive Arbeit von mehreren Motoren. In dieser Arbeit wurde die Bewegung von Kugeln als Modell für Zellorganellen, die von Kinesin-1 Molekülen gezogen werden, in Anhängigkeit von der Motorendichte auf der Kugeloberfläche und unterschiedlichen Kugeldurchmessern in vitro untersuchten. Die Transportparameter Weglänge, Geschwindigkeit und die erzeugte Kraft wurden gemessen. Die Ergebnisse zeigen, dass die Transportgeschwindigkeit leicht abnimmt, wohingegen die Weglänge und die erzeugten Kräfte mit steigender Molekülkonzentration zunehmen. Die tatsächliche Anzahl der Motoren, die aktiv am Transport der Kugeln beteiligt sind, wurde bestimmt, indem die Änderung des hydrodynamischen Durchmessers der mit Kinesin bedeckten Kugeln mittels dynamischer Lichtstreuung gemessen wurde. Außerdem wurden sterische Effekte des verwendeten Transportsystems in die Berechnung einbezogen. Damit werden Ergebnisse vergleichbar, die für unterschiedliche Kugeldurchmesser und Motorkonzentrationen ermittelt wurden. Zusätzlich wurden die Verteilungen der Weglängen für die kleinste Kugelgröße mit theoretisch ermittelten Verteilungen verglichen. Letzteres ergab durchschnittliche Anzahlen der aktiv am Transport beteiligten Motormoleküle, die mit den experimentell bestimmten Ergebnissen übereinstimmen. KW - Transport KW - Weglänge KW - Geschwindigkeit KW - erzeugte Kraft KW - Kinesin KW - transport KW - run length KW - velocity KW - generated force KW - kinesin Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-15712 ER -