title: Gravity signal transduction in primary roots.
abstract: OBJECTIVE
  The molecular mechanisms that correlate with gravity perception and signal transduction in the tip of angiosperm primary roots are discussed.
  
  
  METHODS
  Gravity provides a cue for downward orientation of plant roots, allowing anchorage of the plant and uptake of the water and nutrients needed for growth and development. Root gravitropism involves a succession of physiological steps: gravity perception and signal transduction (mainly mediated by the columella cells of the root cap); signal transmission to the elongation zone; and curvature response. Interesting new insights into gravity perception and signal transduction within the root tip have accumulated recently by use of a wide range of experimental approaches in physiology, biochemistry, genetics, genomics, proteomics and cell biology. The data suggest a network of signal transduction pathways leading to a lateral redistribution of auxin across the root cap and a possible involvement of cytokinin in initial phases of gravicurvature.
  
  
  CONCLUSIONS
  These new discoveries illustrate the complexity of a highly redundant gravity-signalling process in roots, and help to elucidate the global mechanisms that govern auxin transport and morphogenetic regulation in roots.
authors: Laboratory of Genetics, University of Wisconsin-Madison, 425-G Henry Mall, Madison, WI 53706, USA.
authors: Robyn M
authors: RM
authors: Perrin
authors: Li-Sen
authors: LS
authors: Young
authors: Narayana
authors: N
authors: Murthy U M
authors: Benjamin R
authors: BR
authors: Harrison
authors: Yan
authors: Y
authors: Wang
authors: Jessica L
authors: JL
authors: Will
authors: Patrick H
authors: PH
authors: Masson
mesh_terms: D018522:Gravitropism / Q000502:physiology*; D007473:Ion Channels / Q000502:physiology; D010937:Plant Growth Regulators / Q000502:physiology; D010940:Plant Proteins / Q000378:metabolism; D018517:Plant Roots / Q000235:genetics / Q000254:growth & development* / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*
chemical_list: D007473:Ion Channels; D010937:Plant Growth Regulators; D010940:Plant Proteins