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Article|01 Apr 2021|OPEN
CmRCD1 represses flowering by directly interacting with CmBBX8 in summer chrysanthemum
Lijun Wang1,2, Hua Cheng1, Qi Wang1, Chaona Si1, Yiman Yang1, Yao Yu1, Lijie Zhou1, Lian Ding1, Aiping Song1, Dongqing Xu1, Sumei Chen1, Weimin Fang1, Fadi Chen1 & Jiafu Jiang1,
1State Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Landscaping, Ministry of Agriculture and Rural Affairs, Key Laboratory of Biology of Ornamental Plants in East China, National Forestry and Grassland Administration, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
2Present address: College of Landscape and Ecological Engineering, Hebei University of Engineering, Handan 056038, China

Horticulture Research 8,
Article number: 79 (2021)
doi: 10.1038/hortres.2021.79
Views: 273

Received: 19 Jul 2020
Revised: 21 Dec 2020
Accepted: 06 Feb 2021
Published online: 01 Apr 2021

Abstract

The CmBBX8-CmFTL1 regulatory module is a key determinant in the transition from vegetative growth to reproductive development in summer-flowering chrysanthemum. However, the detailed regulatory mechanism of CmBBX8-mediated flowering remains elusive. In this study, we revealed that RADICAL-INDUCED CELL DEATH 1 (CmRCD1) physically associated with CmBBX8 through bimolecular fluorescence complementation (BiFC), pulldown and Coimmunoprecipitation (CoIP) assays. Furthermore, the RCD1-SRO1-TAF4 (RST) domain of CmRCD1 and the B-box of CmBBX8 mediated their interaction. In addition, Luciferase (LUC) assays and electrophoretic mobility shift assay (EMSAs) showed that CmRCD1 repressed the transcriptional activity of CmBBX8 and interfered with its binding to the CmFTL1 promoter, thereby leading to delayed flowering in the summer chrysanthemum ‘Yuuka’. These results provide insight into the molecular framework of CmRCD1-CmBBX8-mediated flowering in chrysanthemum.