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SUMMARY:Made in the shade: light signals\, phytochromes and plant  develop
 ment - Professor Garry Whitelam\, University of Leicester
DTSTART:20070503T150000Z
DTEND:20070503T160000Z
UID:TALK6018@talks.cam.ac.uk
CONTACT:3901
DESCRIPTION:The phytochromes are a family of reversibly photochromic plant
  photoreceptors that perceive spatial and temporal informational signals a
 nd initiate appropriate adaptive developmental strategies. One such strate
 gy involves the phytochrome-mediated perception of the far-red radiation (
 700-800 nm) reflected/scattered from the leaves of nearby vegetation\, pro
 viding an early warning of potential shading\, and leading to a series of 
 developmental responses\, the 'shade-avoidance syndrome'\, that can result
  in the overgrowth of those neighbours. Upon sensing a reflected far-red l
 ight signal\, a shade-avoiding plant very rapidly exhibits enhanced elonga
 tion growth. If the rapid elongation strategy is unsuccessful\, and the fa
 r-red light signal persists\, then other aspects of the shade-avoidance sy
 ndrome cause accelerated flowering and early production of seeds\, enhanci
 ng the probability of survival. Despite its adaptive significance\, little
  is known about the molecular events that connect light perception with in
 creased elongation growth in shade avoidance. Using microarrays\, we have 
 shown that an early event following the perception of the far-red light si
 gnal is the altered expression of numerous genes. For several of these gen
 es\, altered expression in response to far-red light signals is gated by t
 he circadian clock. Furthermore\, the rapid shade avoidance elongation gro
 wth response is gated by the circadian clock\, being most apparent around 
 (subjective) dusk. Several of the far-red-responsive genes are essential f
 or the normal display of the rapid elongation growth response. Preliminary
  evidence suggests that one of the earliest molecular events in the transd
 uction of the far-red rich light signal is the stabilisation of PIFs\; phy
 tochrome-interacting transcriptional regulators. \n\nhttp://www.le.ac.uk/b
 iology/staff/blgcw1.htm
LOCATION:Department of Plant Sciences\, Large Lecture Theatre
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