miR156-regulated SPL transcription factors define an endogenous flowering pathway in Arabidopsis thaliana.
The FT gene integrates several external and endogenous cues controlling flowering, including information on day length. A complex of the mobile FT protein and the bZIP transcription factor FD in turn has a central role in activating genes that execute the switch from vegetative to reproductive development. Here we reveal that microRNA156-targeted SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPL) genes not only act downstream of FT/FD, but also define a separate endogenous flowering pathway. High levels of miR156 in young plants prevent precocious flowering. A subsequent day length-independent decline in miR156 abundance provides a permissive environment for flowering and is paralleled by a rise in SPL levels. At the shoot apex, FT/FD and SPLs converge on an overlapping set of targets, with SPLs directly activating flower-promoting MADS box genes, providing a molecular substrate for both the redundant activities and the feed-forward action of the miR156/SPL and FT/FD modules in flowering control.
Wang
Jia-Wei
JW
Department of Molecular Biology, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany.
Czech
Benjamin
B
Weigel
Detlef
D
D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D035264:Flowers / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D049452:Green Fluorescent Proteins / Q000378:metabolism; D018519:Meristem / Q000254:growth & development; D035683:MicroRNAs / Q000378:metabolism*; D015398:Signal Transduction; D015534:Trans-Activators; D014157:Transcription Factors / Q000378:metabolism*
D029681:Arabidopsis Proteins; C503117:FD protein, Arabidopsis; C418905:FT protein, Arabidopsis; D035683:MicroRNAs; C531404:SPL9 protein, Arabidopsis; D015534:Trans-Activators; D014157:Transcription Factors; D049452:Green Fluorescent Proteins