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SUMMARY:From gravitropism to dynamical posture control: proprioception in 
 plants - Bruno Moulia\, Research Director\, INRA
DTSTART:20130508T130000Z
DTEND:20130508T140000Z
UID:TALK44690@talks.cam.ac.uk
CONTACT:Helen Mawdsley
DESCRIPTION:Gravitropism is a key determinant of the form and posture of l
 and plants. Shoot gravitropism is triggered when statocysts sense the loca
 l angle of the growing organ relative to the gravitational field. Lateral 
 transport of the hormone auxin to the lower side is then enhanced\, result
 ing in differential gene expression and cell elongation causing the organ 
 to bend. However\, little was know known about the dynamics\, regulation\,
  and diversity of the entire bending and straightening process. \n\nRecent
 ly\, using vital kinematic imaging of the gravitropic movement of differen
 t organs from 11 angiosperms sampling the phylogenic tree of land angiospe
 rms\, we found that gravitropic straightening shares common traits across 
 species\, organs\, and orders of magnitude. Surprisingly\, the minimal dyn
 amic model accounting for these traits is not the widely cited gravisensin
 g law but one that also takes into account the sensing of local curvature\
 , i.e. a proprioception.  A minimal dynamical model of the movement of the
  plant during gravitropism and posture control \, called the AC model has 
 been designed \, that can explain most of the diversity observed in experi
 ments.  Moreover the entire dynamics of the bending/straightening response
  is described by a single dimensionless “bending number” B that reflec
 ts the ratio between graviceptive and proprioceptive sensitivities\, and d
 efines both the final shape of the organ at equilibrium and the timing of 
 curving and straightening. Proprioceptive sensing is thus as important as 
 gravisensing in dynamical gravitropic control. \nIn this seminar\, I will 
 discuss the possible mechanisms for plant proprioception\, and their conse
 quences for the involvement of the auxin signalling network in plant gravi
 tropism\, as well as the use of model-assisted phenotyping in genetic stud
 ies\n\nR.BASTIEN\, T. BOHR\,  B. MOULIA.† * \, S.DOUADY.†  \, 2013 . A
  unifying model of shoot gravitropism reveals proprioception as a central 
 feature of posture control in plant. PNAS 110 (2 ): 755–760 († co-PI l
 ast authors\, * corresponding author )  \nJ DUMAIS 2013 Beyond the sine la
 w of plant gravitropism (commentary of the paper by Bastien et al 2013)  P
 NAS  110 (2 ) 391–392. \n
LOCATION:Auditorium of The Sainsbury Laboratory (Bateman Street)
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