title: MYB96 shapes the circadian gating of ABA signaling in Arabidopsis.
abstract: Circadian clocks regulate the rhythms of biological activities with a period of approximately 24-hours and synchronize plant metabolism and physiology with the environmental cycles. The clock also gates responses to environmental stresses to maximize fitness advantages. Here we report that the MYB96 transcription factor is connected with the clock oscillator to shape the circadian gating of abscisic acid (ABA) responses. MYB96 directly binds to the TIMING OF CAB EXPRESSION 1 (TOC1) promoter to positively regulate its expression. The use of myb96 mutant plants shows that this regulation is essential for the gated induction of TOC1 by ABA. In turn, MYB96 induction by ABA is also altered in toc1-3 mutant plants. The increased tolerance to drought of MYB96 over-expressing plants is decreased in the toc1-3 mutant background, suggesting that MYB96 and TOC1 intersect the circadian clock and ABA signaling. The MYB96-TOC1 function might be also regulated by the clock component CIRCADIAN CLOCK-ASSOCIATED 1 (CCA1), which binds to the MYB96 promoter and alters its circadian expression. Thus, a complex circuitry of CCA1-MYB96-TOC1 regulatory interactions provides the mechanistic basis underlying the connection between circadian and stress signaling to optimize plant fitness to ambient stresses.
authors.affiliation: Department of Bioactive Material Sciences and Research Center of Bioactive Materials, Chonbuk National University, Jeonju 561-756, Republic of Korea.
authors.forename: Hong Gil
authors.initials: HG
authors.lastname: Lee
authors.affiliation: Plant Development and Signal Transduction, Center for Research in Agricultural Genomics (CRAG), Parc de Recerca UAB, Bellaterra (Cerdanyola del Vallés), Barcelona, Spain.|Consejo Superior de Investigaciones Científicas (CSIC), Barcelona, Spain.
authors.forename: Paloma
authors.initials: P
authors.lastname: Mas
authors.affiliation: Department of Bioactive Material Sciences and Research Center of Bioactive Materials, Chonbuk National University, Jeonju 561-756, Republic of Korea.|Department of Chemistry and Research Institute of Physics and Chemistry, Chonbuk National University, Jeonju 561-756, Republic of Korea.
authors.forename: Pil Joon
authors.initials: PJ
authors.lastname: Seo
mesh_terms: D000040:Abscisic Acid / Q000502:physiology*; D000222:Adaptation, Physiological; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D057906:Circadian Clocks; D003681:Dehydration; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D015533:Transcriptional Activation
chemical_list: D029681:Arabidopsis Proteins; C114425:CCA1 protein, Arabidopsis; C544823:MYB96 protein, Arabidopsis; C411822:TOC1 protein, Arabidopsis; D014157:Transcription Factors; D000040:Abscisic Acid