Arabidopsis thaliana CENTRORADIALIS homologue (ATC) acts systemically to inhibit floral initiation in Arabidopsis.
Floral initiation is orchestrated by systemic floral activators and inhibitors. This remote-control system may integrate environmental cues to modulate floral initiation. Recently, FLOWERING LOCUS T (FT) was found to be a florigen. However, the identity of systemic floral inhibitor or anti-florigen remains to be elucidated. Here we show that Arabidopsis thaliana CENTRORADIALIS homologue (ATC), an Arabidopsis FT homologue, may act in a non-cell autonomous manner to inhibit floral initiation. Analysis of the ATC null mutant revealed that ATC is a short-day-induced floral inhibitor. Cell type-specific expression showed that companion cells and apex that express ATC are sufficient to inhibit floral initiation. Histochemical analysis showed that the promoter activity of ATC was mainly found in vasculature but under the detection limit in apex, a finding that suggests that ATC may move from the vasculature to the apex to influence flowering. Consistent with this notion, Arabidopsis seedling grafting experiments demonstrated that ATC moved over a long distance and that floral inhibition by ATC is graft transmissible. ATC probably antagonizes FT activity, because both ATC and FT interact with FD and affect the same downstream meristem identity genes APETALA1, in an opposite manner. Thus, photoperiodic variations may trigger functionally opposite FT homologues to systemically influence floral initiation.
Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, National Chung-Hsing University and Academia Sinica, Taipei 11529, Taiwan.
Nien-Chen
NC
Huang
Wann-Neng
WN
Jane
Jychian
J
Chen
Tien-Shin
TS
Yu
D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism / Q000648:ultrastructure; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D020285:Cryoelectron Microscopy; D060405:Florigen / Q000378:metabolism*; D035264:Flowers / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism / Q000648:ultrastructure; D018506:Gene Expression Regulation, Plant; D018519:Meristem / Q000235:genetics / Q000378:metabolism; D016254:Mutagenesis, Insertional; D010641:Phenotype; D017440:Photoperiod; D010937:Plant Growth Regulators / Q000378:metabolism*; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic; D018749:RNA, Plant / Q000235:genetics; D036226:Seedlings; D015398:Signal Transduction / Q000235:genetics; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
D029681:Arabidopsis Proteins; D060405:Florigen; D010937:Plant Growth Regulators; D018749:RNA, Plant; D014157:Transcription Factors