The B-box family gene STO (BBX24) in Arabidopsis thaliana regulates flowering time in different pathways.
Flowering at the appropriate time is crucial for reproductive success and is strongly influenced by various pathways such as photoperiod, circadian clock, FRIGIDA and vernalization. Although each separate pathway has been extensively studied, much less is known about the interactions between them. In this study we have investigated the relationship between the photoperiod/circadian clock gene and FRIGIDA/FLC by characterizing the function of the B-box STO gene family. STO has two B-box Zn-finger domains but lacks the CCT domain. Its expression is controlled by circadian rhythm and is affected by environmental factors and phytohormones. Loss and gain of function mutants show diversiform phenotypes from seed germination to flowering. The sto-1 mutant flowers later than the wild type (WT) under short day growth conditions, while over-expression of STO causes early flowering both in long and short days. STO over-expression not only reduces FLC expression level but it also activates FT and SOC1 expression. It also does not rely on the other B-box gene CO or change the circadian clock system to activate FT and SOC1. Furthermore, the STO activation of FT and SOC1 expression is independent of the repression of FLC; rather STO and FLC compete with each other to regulate downstream genes. Our results indicate that photoperiod and the circadian clock pathway gene STO can affect the key flowering time genes FLC and FT/SOC1 separately, and reveals a novel perspective to the mechanism of flowering regulation.
Peking University-Yale Joint Research Center of Agricultural and Plant Molecular Biology, National Key Laboratory of Protein Engineering and Plant Gene Engineering, College of Life Sciences, Peking University, Beijing, China ; Department of Biological and Environmental Sciences, Gothenburg University, Gothenburg, Sweden.
Feng
F
Li
Peking University-Yale Joint Research Center of Agricultural and Plant Molecular Biology, National Key Laboratory of Protein Engineering and Plant Gene Engineering, College of Life Sciences, Peking University, Beijing, China.
Jinjing
J
Sun
Peking University-Yale Joint Research Center of Agricultural and Plant Molecular Biology, National Key Laboratory of Protein Engineering and Plant Gene Engineering, College of Life Sciences, Peking University, Beijing, China.
Donghui
D
Wang
Peking University-Yale Joint Research Center of Agricultural and Plant Molecular Biology, National Key Laboratory of Protein Engineering and Plant Gene Engineering, College of Life Sciences, Peking University, Beijing, China.
Shunong
S
Bai
Department of Biological and Environmental Sciences, Gothenburg University, Gothenburg, Sweden.
Adrian K
AK
Clarke
Department of Biological and Environmental Sciences, Gothenburg University, Gothenburg, Sweden.
Magnus
M
Holm
D029681:Arabidopsis Proteins / Q000235:genetics*; D057906:Circadian Clocks / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics; D035264:Flowers / Q000235:genetics*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000235:genetics* / Q000528:radiation effects; D005838:Genotype; D026161:MADS Domain Proteins / Q000235:genetics; D009154:Mutation; D056950:Period Circadian Proteins / Q000235:genetics; D017440:Photoperiod; D010937:Plant Growth Regulators / Q000494:pharmacology; D012097:Repressor Proteins / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000235:genetics*; D013997:Time Factors; D014157:Transcription Factors / Q000235:genetics
C419046:AGL20 protein, Arabidopsis; D029681:Arabidopsis Proteins; C585246:BBX24 protein, Arabidopsis; C092776:CONSTANS protein, Arabidopsis; D004268:DNA-Binding Proteins; C418902:At5g10140 protein, Arabidopsis; C414613:FRI protein, Arabidopsis; C418905:FT protein, Arabidopsis; D026161:MADS Domain Proteins; D056950:Period Circadian Proteins; D010937:Plant Growth Regulators; D012097:Repressor Proteins; D014157:Transcription Factors