Suchergebnisse

The ability to interpret daily and seasonal alterations in light and temperature signals is essential for plant survival. This is particularly important during seedling establishment when the phytochrome photoreceptors activate photosynthetic pigment production for photoautotrophic growth. Phytochromes accomplish this partly through the suppression of PHYTOCHROME INTERACTING FACTORS (PIFs), negative regulators of chlorophyll and carotenoid biosynthesis. While the bZIP transcription factor LONG HYPOCOTYL 5 (HY5), a potent PIF antagonist, promotes photosynthetic pigment accumulation in response to light. Here we demonstrate that by directly targeting a common promoter cis-element (G-box), HY5 and PIFs form a dynamic activation-suppression transcriptional module responsive to light and temperature cues. This antagonistic regulatory module provides a simple, direct mechanism through which environmental change can redirect transcriptional control of genes required for photosynthesis and photoprotection. In the regulation of photopigment biosynthesis genes, HY5 and PIFs do not operate alone, but with the circadian clock. However, sudden changes in light or temperature conditions can trigger changes in HY5 and PIFs abundance that adjust the expression of common target genes to optimise photosynthetic performance and growth. ; GTO and KPL are funded by a UK Biotechnology and Biological Sciences Research Council (BBSRC) grant BB/F005237/1 (ROBuST project) awarded to KJH and the European Union FP7 (TiMet, contract 245143). GTO is also supported by a Marie Curie Actions FP7-CIG (PCIG11-GA-2012-321649) award. HJ received a Postgraduate Award provided by the BBSRC and the Scottish Universities Life Science Alliance (SULSA). MRC and JBT are funded by grants from the Spanish Dirección General de Investigación (BIO2011-23680 and PIM2010IPO-00660), Generalitat de Catalunya (2009SGR-26 and XRB), Programa Iberoamericano de Ciencia y Tecnologia para el Desarrollo (IBERCAROT), and European Union FP7 (TiMet, contract 245143) awarded to MRC. ; Peer reviewed

El reloj circadiano endógeno permite a los organismos adaptar su crecimiento y desarrollo a los cambios ambientales. Aquí describimos cómo el reloj circadiano es empleado para coordinar las respuestas a la señal clave de las auxinas durante la aparición de la raíz lateral (LR). En la planta modelo Arabidopsis thaliana, LRs proceden de un grupo de células madre de raíz profunda, que requiere que los nuevos órganos emerjan a través de tejidos subyacentes de la raíz. Nos informan que el desarrollo del reloj circadiano reprogramara a LR. El metabolito y los perfiles de transcripción revelaron que el reloj circadiano controla los niveles de auxina, incluyendo genes relacionados con la respuesta de auxinas AIA represor14 y la auxina oxidasa AtDAO2. Las plantas carecen de componentes de reloj del núcleo para indicar o exhibir la aparición de defectos en LR. Concluimos que los actos del reloj circadiano conducen a la señalización de la auxina durante el desarrollo de la LR para facilitar el surgimiento de órganos. ; The endogenous circadian clock enables organisms to adapt their growth and development to environmental changes. Here we describe how the circadian clock is employed to coordinate responses to the key signal auxin during lateral root (LR) emergence. In the model plant, Arabidopsis thaliana, LRs originate from a group of stem cells deep within the root, necessitating that new organs emerge through overlying root tissues. We report that the circadian clock is rephased during LR development. Metabolite and transcript profiling revealed that the circadian clock controls the levels of auxin and auxin-related genes including the auxin response repressor IAA14 and auxin oxidase AtDAO2. Plants lacking or overexpressing core clock components exhibit LR emergence defects. We conclude that the circadian clock acts to gate auxin signalling during LR development to facilitate organ emergence. ; Acknowledge Engineering and Physical Sciences Research Council (EPSRC)funding to the Centre for Plant Integrative Biology (CPIB) BB/D019613/1; U.V, K.S. and M.J.B. acknowledge funding from BBSRC grant BB/H020314/1; K.K., M.H.W. and K.S. acknowledge the support of the European Research Community Advanced Investigator Funding to M.J.B (FUTUREROOTS); D.M.W. and M.J.B. acknowledge BBSRC funding from grant BB/J009717/1 and U.V. and D.M.W. from the BBSRC Professorial Research Fellowship funding to M.J.B. grant BB/G023972/1; JSPS Fellowship to T.G., H.F. and M.J.B.; BBSRC funding for F.C.R and A.A.R.W. from grant BB/D017904/1; and Royal Society-Wolfson Merit Award to M.J.B. Work at the University of Liverpool by P.D.G and A.J.H was supported by the BBSRC/EPSRC-funded ROBuST SABR project BB/F005318/1 and BBSRC grant BB/K018078/1. M.L. and L.L. were supported by the Région Languedoc Roussillon ('Chercheur d'Avenir' grant to LL) and the Agropolis Fondation Rhizopolis project. B.P. acknowledges the support of an Intra-European Fellowship for Career Development under the seventh framework of the European Commission (IEF-2008-220506), an EMBO Long-Term Fellowship, a European Reintegration Grant under the seventh framework of the European Commission (ERG-2010-276662). K.L. acknowledges the Swedish Governmental Agency for Innovation Systems (VINNOVA)and the Swedish Research Council (VR). W.A.P. and A.S.M. acknowledge funding from the Maryland Agricultural Experiment Station and DOE Physical Biosciences Basic Energy Sciences (DE-FG02-13ER16405). ; peerReviewed