| Abstract Detail
Mechanisms of Gene Regulation Rubin, Grit [1], Dieterich, Jens-Holger [2], Stitt, Mark [2], Scheible, Wolf-Rüdiger [2]. Repression of anthocyan synthesis in Arabidopsis by three related, nitrate-induced transcription factors acting upstream of PAP1. Signals derived from nitrate per se have a broad impact on gene expression, resulting in the reprogramming of nitrogen and carbon metabolism to induce efficient nitrate uptake and assimilation. Root growth and architecture, induction of flowering, senescence and anthocyan production are also adjusted by signals derived from internal and external nitrate. To obtain insights in the regulatory infrastructure underlying these changes, transcription factors (TFs) regulated by nitrate were identified using Affymetrix genechips and high-throughput real time RT-PCR. Out of these, three highly nitrate-regulated, related genes were selected for reverse-genetic, functional analysis. Constitutive over-expression (OX) of each of the three TF genes leads to a “stay green” phenotype with strongly reduced anthocyan accumulation in nitrogen-deprived conditions both in young seedlings grown in axenic culture and in adult plants grown on soil. Additional visual phenotypes of the OX plants include accelerated development and a higher germination rate in axenic culture as well as early flowering with more lateral branches when grown on soil under low nitrogen conditions. Real time RT-PCR and Affymetrix genechip analysis reveal strongly reduced expression of regulatory genes (PAP1, PAP2) and several key enzymes of anthocyan biosynthesis (e.g. DFR, LDOX, UFGT, GST-like) in all OX lines grown in N-deprived conditions, thus confirming the whole plant “stay green” phenotype at the molecular level.
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1 - Max-Planck Institute for Molecular Plant Physiology, Metabolic networks Dep.2, Wissenschaftspark Golm, Am Mühlenberg1, Potsdam (OT) Golm, 14476, Germany
2 - Max-Planck Institute for Molecular Plant Physiology, Metabolic networks Dep.2
Keywords:
transcription factors
anthocyan synthesis
nitrate
PAP.
Presentation Type: Plant Biology Abstract
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P36024
Abstract ID:880 |
