Qian Tang1,2, Emilie Guittard-Crilat1, Régis Maldiney1, Yvette Habricot3,4, Emile Miginiac1, Jean-Pierre Bouly5,6, Sandrine Lebreton1. 1. Adaptation des Plantes aux Contraintes Environnementales, Sorbonne Universités, UPMC Univ Paris 06, URF5, 75005, Paris, France. 2. Plant Biological Sciences Graduate Program, Department of Horticultural Science, Microbial and Plant Genomics Institute, University of Minnesota, 1970 Folwell Avenue, Saint Paul, MN, 55108, USA. 3. Biologie du Développement, Sorbonne Universités, UPMC Univ. Paris 06, UMR 7622, 75005, Paris, France. 4. Biologie du Développement, CNRS, UMR 7622, 75005, Paris, France. 5. Computational and Quantitative Biology, Sorbonne Universités, UPMC Univ. Paris 06, UMR 7238, 75005, Paris, France. jean-pierre.bouly@upmc.fr. 6. Computational and Quantitative Biology, CNRS-UPMC UMR 7238, 15, rue de l'Ecole de Médecine, 75006, Paris, France. jean-pierre.bouly@upmc.fr.
Abstract
MAIN CONCLUSION: Arabidopsis PHS1, initially known as an actor of cytoskeleton organization, is a positive regulator of flowering in the photoperiodic and autonomous pathways by modulating both CO and FLC mRNA levels. Protein phosphorylation and dephosphorylation is a major type of post-translational modification, controlling many biological processes. In Arabidopsis thaliana, five genes encoding MAPK phosphatases (MKP)-like proteins have been identified. Among them, PROPYZAMIDE HYPERSENSITIVE 1 (PHS1) encoding a dual-specificity protein tyrosine phosphatase (DsPTP) has been shown to be involved in microtubule organization, germination and ABA-regulated stomatal opening. Here, we demonstrate that PHS1 also regulates flowering under long-day and short-day conditions. Using physiological, genetic and molecular approaches, we have shown that the late flowering phenotype of the knock-out phs1-5 mutant is linked to a higher expression of FLOWERING LOCUS C (FLC). In contrast, a decline of both CONSTANS (CO) and FLOWERING LOCUS T (FT) expression is observed in the knock-out phs1-5 mutant, especially at the end of the light period under long-day conditions when the induction of flowering occurs. We show that this partial loss of sensitivity to photoperiodic induction is independent of FLC. Our results thus indicate that PHS1 plays a dual role in flowering, in the photoperiodic and autonomous pathways, by modulating both CO and FLC mRNA levels. Our work reveals a novel actor in the complex network of the flowering regulation.
MAIN CONCLUSION:ArabidopsisPHS1, initially known as an actor of cytoskeleton organization, is a positive regulator of flowering in the photoperiodic and autonomous pathways by modulating both CO and FLC mRNA levels. Protein phosphorylation and dephosphorylation is a major type of post-translational modification, controlling many biological processes. In Arabidopsis thaliana, five genes encoding MAPK phosphatases (MKP)-like proteins have been identified. Among them, PROPYZAMIDE HYPERSENSITIVE 1 (PHS1) encoding a dual-specificity protein tyrosine phosphatase (DsPTP) has been shown to be involved in microtubule organization, germination and ABA-regulated stomatal opening. Here, we demonstrate that PHS1 also regulates flowering under long-day and short-day conditions. Using physiological, genetic and molecular approaches, we have shown that the late flowering phenotype of the knock-out phs1-5 mutant is linked to a higher expression of FLOWERING LOCUS C (FLC). In contrast, a decline of both CONSTANS (CO) and FLOWERING LOCUS T (FT) expression is observed in the knock-out phs1-5 mutant, especially at the end of the light period under long-day conditions when the induction of flowering occurs. We show that this partial loss of sensitivity to photoperiodic induction is independent of FLC. Our results thus indicate that PHS1 plays a dual role in flowering, in the photoperiodic and autonomous pathways, by modulating both CO and FLC mRNA levels. Our work reveals a novel actor in the complex network of the flowering regulation.
Entities:
Keywords:
Arabidopsis; CONSTANS; FLOWERING LOCUS C (FLC); FLOWERING LOCUS T (FT); Flowering; Phosphatase