title: Gating of the rapid shade-avoidance response by the circadian clock in plants.
abstract: The phytochromes are a family of plant photoreceptor proteins that control several adaptive developmental strategies. For example, the phytochromes perceive far-red light (wavelengths between 700 and 800 nm) reflected or scattered from the leaves of nearby vegetation. This provides an early warning of potential shading, and triggers a series of 'shade-avoidance' responses, such as a rapid increase in elongation, by which the plant attempts to overgrow its neighbours. Other, less immediate, responses include accelerated flowering and early production of seeds. However, little is known about the molecular events that connect light perception with increased growth in shade avoidance. Here we show that the circadian clock gates this rapid shade-avoidance response. It is most apparent around dusk and is accompanied by altered expression of several genes. One of these rapidly responsive genes encodes a basic helix-loop-helix protein, PIL1, previously shown to interact with the clock protein TOC1 (ref. 4). Furthermore PIL1 and TOC1 are both required for the accelerated growth associated with the shade-avoidance response.
authors.affiliation: Department of Biology, University of Leicester, Leicester LE1 7RH, UK.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Salter
authors.forename: Keara A
authors.initials: KA
authors.lastname: Franklin
authors.forename: Garry C
authors.initials: GC
authors.lastname: Whitelam
mesh_terms: D000222:Adaptation, Physiological / Q000528:radiation effects; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000502:physiology* / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D002940:Circadian Rhythm / Q000502:physiology* / Q000528:radiation effects; D003624:Darkness; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects; D018546:Hypocotyl / Q000235:genetics / Q000254:growth & development / Q000502:physiology / Q000528:radiation effects; D008027:Light; D009154:Mutation / Q000235:genetics; D017440:Photoperiod; D010834:Phytochrome / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D036226:Seedlings / Q000235:genetics / Q000254:growth & development / Q000502:physiology / Q000528:radiation effects; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C456844:PIL1 protein, Arabidopsis; D012333:RNA, Messenger; D018749:RNA, Plant; C411822:TOC1 protein, Arabidopsis; D014157:Transcription Factors; D010834:Phytochrome