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Research article - Peer-reviewed, 2011

Integrating long-day flowering signals: a LEAFY binding site is essential for proper photoperiodic activation of APETALA1

Benlloch, Reyes; Kim, Min Chul; Sayou, Camille; Thevenon, Emmanuel; Parcy, Francois; Nilsson, Ove


The transition to flowering in Arabidopsis is characterized by the sharp and localized upregulation of APETALA1 (AP1) transcription in the newly formed floral primordia. Both the flower meristem-identity gene LEAFY (LFY) and the photoperiod pathway involving the FLOWERING LOCUS T (FT) and FD genes contribute to this upregulation. These pathways have been proposed to act independently but their respective contributions and mode of interaction have remained elusive. To address these questions, we studied the AP1 regulatory region. Combining in vitro and in vivo approaches, we identified which of the three putative LFY binding sites present in the AP1 promoter is essential for its activation by LFY. Interestingly, we found that this site is also important for the correct photoperiodic-dependent upregulation of AP1. In contrast, a previously proposed putative FD-binding site appears dispensable and unable to bind FD and we found no evidence for FD binding to other sites in the AP1 promoter, suggesting that the FT/FD-dependent activation of AP1 might be indirect. Altogether, our data give new insight into the interaction between the FT and LFY pathways in the upregulation of AP1 transcription under long-day conditions.


APETALA1; LEAFY; FLOWERING LOCUS T; FLOWERING LOCUS D; floral induction; photoperiod

Published in

Plant Journal
2011, volume: 67, number: 6, pages: 1094-1102

Authors' information

Benlloch, Reyes
Swedish University of Agricultural Sciences, Department of Forest Genetics and Plant Physiology
Kim, Min Chul
Gyeongsang National University
Camille, Sayou
National Institute of Agricultural Research (INRA)
Thévenon, Emmanuel
National Institute of Agricultural Research (INRA)
Parcy, Francois
National Institute of Agricultural Research (INRA)
Swedish University of Agricultural Sciences, Department of Forest Genetics and Plant Physiology

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Other Biological Topics

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