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Research article2018Peer reviewedOpen access

LEAFY activity is post-transcriptionally regulated by BLADE ON PETIOLE2 and CULLIN3 in Arabidopsis

Chahtane, Hicham; Zhang, Bo; Norberg, Mikael; LeMasson, Marie; Thevenon, Emmanuel; Bako, Laszlo; Benlloch, Reyes; Holmlund, Mattias; Parcy, Francois; Nilsson, Ove; Vachon, Gilles

Abstract

The Arabidopsis LEAFY (LFY) transcription factor is a key regulator of floral meristem emergence and identity. LFY interacts genetically and physically with UNUSUAL FLORAL ORGANS, a substrate adaptor of CULLIN1-RING ubiquitin ligase complexes (CRL1). The functionally redundant genes BLADE ON PETIOLE1 (BOP1) and -2 (BOP2) are potential candidates to regulate LFY activity and have recently been shown to be substrate adaptors of CULLIN3 (CUL3)-RING ubiquitin ligases (CRL3). We tested the hypothesis that LFY activity is controlled by BOPs and CUL3s in plants and that LFY is a substrate for ubiquitination by BOP-containing CRL3 complexes. When constitutively expressed, LFY activity is fully dependent on BOP2 as well as on CUL3A and B to regulate target genes such as APETALA1 and to induce ectopic flower formation. We also show that LFY and BOP2 proteins interact physically and that LFY-dependent ubiquitinated species are produced invitro in a reconstituted cell-free CRL3 system in the presence of LFY, BOP2 and CUL3. This new post-translational regulation of LFY activity by CRL3 complexes makes it a unique transcription factor subjected to a positive dual regulation by both CRL1 and CRL3 complexes and suggests a novel mechanism for promoting flower development.

Keywords

BLADE-ON-PETIOLE; cullin 3; flower development; inflorescence; LEAFY; post-transcriptional regulation; ubiquitination

Published in

New Phytologist
2018, Volume: 220, number: 2, pages: 579-592
Publisher: WILEY