The small glycine-rich RNA binding protein AtGRP7 promotes floral transition in Arabidopsis thaliana.
The RNA binding protein AtGRP7 is part of a circadian slave oscillator in Arabidopsis thaliana that negatively autoregulates its own mRNA, and affects the levels of other transcripts. Here, we identify a novel role for AtGRP7 as a flowering-time gene. An atgrp7-1 T-DNA mutant flowers later than wild-type plants under both long and short days, and independent RNA interference lines with reduced levels of AtGRP7, and the closely related AtGRP8 protein, are also late flowering, particularly in short photoperiods. Consistent with the retention of a photoperiodic response, the transcript encoding the key photoperiodic regulator CONSTANS oscillates with a similar pattern in atgrp7-1 and wild-type plants. In both the RNAi lines and in the atgrp7-1 mutant transcript levels for the floral repressor FLC are elevated. Conversely, in transgenic plants ectopically overexpressing AtGRP7, the transition to flowering is accelerated mainly in short days, with a concomitant reduction in FLC abundance. The late-flowering phenotype of the RNAi lines is suppressed by introducing the flc-3 loss-of-function mutation, suggesting that AtGRP7 promotes floral transition, at least partly by downregulating FLC. Furthermore, vernalization overrides the late-flowering phenotype. Retention of both the photoperiodic response and vernalization response are features of autonomous pathway mutants, suggesting that AtGRP7 is a novel member of the autonomous pathway.
Streitner
Corinna
C
Department of Molecular Cell Physiology, University of Bielefeld, Bielefeld, GermanyCenter for Plant Science Innovation and Department of Plant Pathology, University of Nebraska, Lincoln, NE, USA.
Danisman
Selahattin
S
Department of Molecular Cell Physiology, University of Bielefeld, Bielefeld, GermanyCenter for Plant Science Innovation and Department of Plant Pathology, University of Nebraska, Lincoln, NE, USA.
Wehrle
Franziska
F
Department of Molecular Cell Physiology, University of Bielefeld, Bielefeld, GermanyCenter for Plant Science Innovation and Department of Plant Pathology, University of Nebraska, Lincoln, NE, USA.
Schöning
Jan C
JC
Department of Molecular Cell Physiology, University of Bielefeld, Bielefeld, GermanyCenter for Plant Science Innovation and Department of Plant Pathology, University of Nebraska, Lincoln, NE, USA.
Alfano
James R
JR
Department of Molecular Cell Physiology, University of Bielefeld, Bielefeld, GermanyCenter for Plant Science Innovation and Department of Plant Pathology, University of Nebraska, Lincoln, NE, USA.
Staiger
Dorothee
D
Department of Molecular Cell Physiology, University of Bielefeld, Bielefeld, GermanyCenter for Plant Science Innovation and Department of Plant Pathology, University of Nebraska, Lincoln, NE, USA.
D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics; D035264:Flowers / Q000235:genetics / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D026161:MADS Domain Proteins / Q000235:genetics / Q000378:metabolism; D016254:Mutagenesis, Insertional; D017440:Photoperiod; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D018749:RNA, Plant / Q000235:genetics; D016601:RNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism
D029681:Arabidopsis Proteins; D004269:DNA, Bacterial; D026161:MADS Domain Proteins; D018749:RNA, Plant; D016601:RNA-Binding Proteins; C118496:GRP7 protein, Arabidopsis; C418902:At5g10140 protein, Arabidopsis; C036483:T-DNA