title: Red Light-Mediated Degradation of CONSTANS by the E3 Ubiquitin Ligase HOS1 Regulates Photoperiodic Flowering in Arabidopsis.
abstract: The regulation of CONSTANS (CO) gene expression is crucial to accurately measure changes in daylength, which influences flowering time in Arabidopsis thaliana. CO expression is under both transcriptional and posttranslational control mechanisms. We previously showed that the E3 ubiquitin ligase HIGH EXPRESSION OF OSMOTICALLY RESPONSIVE GENES1 (HOS1) physically interacts with CO in Arabidopsis. This interaction is required to precisely modulate the timing of CO accumulation and, consequently, to maintain low levels of FLOWERING LOCUS T expression during the first part of the day. The data presented here demonstrate that HOS1 is involved in the red light-mediated degradation of CO that takes place in the early stages of the daylight period. Our results show that phytochrome B (phyB) is able to regulate flowering time, acting in the phloem companion cells, as previously described for CO and HOS1. Moreover, we reveal that phyB physically interacts with HOS1 and CO, indicating that the three proteins may be present in a complex in planta that is required to coordinate a correct photoperiodic response in Arabidopsis.
authors.affiliation: Centro de Biotecnología y Genómica de Plantas, INIA-UPM, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, 28223 Madrid, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Lazaro
authors.affiliation: Centro de Biotecnología y Genómica de Plantas, INIA-UPM, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, 28223 Madrid, Spain.
authors.forename: Alfonso
authors.initials: A
authors.lastname: Mouriz
authors.affiliation: Centro de Biotecnología y Genómica de Plantas, INIA-UPM, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, 28223 Madrid, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Piñeiro
authors.affiliation: Centro de Biotecnología y Genómica de Plantas, INIA-UPM, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, 28223 Madrid, Spain jarillo@inia.es.
authors.forename: José A
authors.initials: JA
authors.lastname: Jarillo
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D035264:Flowers / Q000502:physiology*; D018506:Gene Expression Regulation, Plant; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D008027:Light; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D052585:Phloem / Q000378:metabolism; D017440:Photoperiod; D051939:Phytochrome B / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D013696:Temperature; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; C092776:CONSTANS protein, Arabidopsis; D004268:DNA-Binding Proteins; C418905:FT protein, Arabidopsis; C425768:HOS1 protein, Arabidopsis; D047908:Intracellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; C497952:PHYB protein, Arabidopsis; D014157:Transcription Factors; D051939:Phytochrome B