The <i>CONSTANS-like 2</i> Gene Serves as a Pivotal Regulator of Flowering in <i>Hemerocallis</i>

<i>Hemerocallis</i> spp. exhibit distinct flower opening times, categorized into nocturnal and diurnal types. Previous studies have demonstrated that the circadian clock and <i>CONSTANS</i> (<i>CO</i>) genes play crucial roles in regulating flowering in <i>H...

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Main Authors: Chunjing Guan, Yike Gao, Ziyi Wang, Qixiang Zhang
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Plants
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Online Access:https://www.mdpi.com/2223-7747/14/13/1996
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author Chunjing Guan
Yike Gao
Ziyi Wang
Qixiang Zhang
author_facet Chunjing Guan
Yike Gao
Ziyi Wang
Qixiang Zhang
author_sort Chunjing Guan
collection DOAJ
description <i>Hemerocallis</i> spp. exhibit distinct flower opening times, categorized into nocturnal and diurnal types. Previous studies have demonstrated that the circadian clock and <i>CONSTANS</i> (<i>CO</i>) genes play crucial roles in regulating flowering in <i>Hemerocallis</i>. However, the key genes that integrate flowering pathways remain largely unknown. To address this gap, we identified potential homologs of the <i>FLOWERING LOCUS T</i> (<i>FT</i>) gene in <i>Hemerocallis</i>. A yeast one-hybrid assay revealed that HfCOL2 and HfLHY directly bind to the <i>HfFT1</i> and <i>HfFT2</i> promoters, thereby activating <i>FT</i> transcription. The expression analysis reveals that <i>HfCOL2</i> expression rhythms not only display opposing patterns between nocturnal and diurnal opening types of <i>Hemerocallis</i> but also between leaf and flower tissues. The peak expression of <i>HfCOL2</i> in flowers aligns closely with the respective opening times of diurnally and nocturnally flowering <i>Hemerocallis</i>. The overexpression of <i>HfCOL2</i> in tobacco plants led to early flowering and prolonged flower longevity. In <i>Hemerocallis</i>, the <i>HfCOL2</i> gene plays a pivotal role not only in photoperiod-induced flowering but also in the circadian rhythm-mediated regulation of flower opening time. Due to the limited availability of plant materials exhibiting distinct flower opening rhythms, research in this area has been constrained. Identifying the key genes in the flowering pathway of <i>Hemerocallis</i> can facilitate a better understanding of the mechanisms by which plants respond to circadian rhythms.
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spelling doaj-art-0199451afef74b32a6e381ea0c1ba7782025-08-20T03:50:16ZengMDPI AGPlants2223-77472025-06-011413199610.3390/plants14131996The <i>CONSTANS-like 2</i> Gene Serves as a Pivotal Regulator of Flowering in <i>Hemerocallis</i>Chunjing Guan0Yike Gao1Ziyi Wang2Qixiang Zhang3Beijing Key Laboratory of Ornamental Plants Germplasm Innovation & Molecular Breeding, National Engineering Research Center for Floriculture, School of Landscape Architecture, Beijing Forestry University, No. 35 Qinghua East Road, Haidian District, Beijing 100083, ChinaBeijing Key Laboratory of Ornamental Plants Germplasm Innovation & Molecular Breeding, National Engineering Research Center for Floriculture, School of Landscape Architecture, Beijing Forestry University, No. 35 Qinghua East Road, Haidian District, Beijing 100083, ChinaBeijing Key Laboratory of Ornamental Plants Germplasm Innovation & Molecular Breeding, National Engineering Research Center for Floriculture, School of Landscape Architecture, Beijing Forestry University, No. 35 Qinghua East Road, Haidian District, Beijing 100083, ChinaBeijing Key Laboratory of Ornamental Plants Germplasm Innovation & Molecular Breeding, National Engineering Research Center for Floriculture, School of Landscape Architecture, Beijing Forestry University, No. 35 Qinghua East Road, Haidian District, Beijing 100083, China<i>Hemerocallis</i> spp. exhibit distinct flower opening times, categorized into nocturnal and diurnal types. Previous studies have demonstrated that the circadian clock and <i>CONSTANS</i> (<i>CO</i>) genes play crucial roles in regulating flowering in <i>Hemerocallis</i>. However, the key genes that integrate flowering pathways remain largely unknown. To address this gap, we identified potential homologs of the <i>FLOWERING LOCUS T</i> (<i>FT</i>) gene in <i>Hemerocallis</i>. A yeast one-hybrid assay revealed that HfCOL2 and HfLHY directly bind to the <i>HfFT1</i> and <i>HfFT2</i> promoters, thereby activating <i>FT</i> transcription. The expression analysis reveals that <i>HfCOL2</i> expression rhythms not only display opposing patterns between nocturnal and diurnal opening types of <i>Hemerocallis</i> but also between leaf and flower tissues. The peak expression of <i>HfCOL2</i> in flowers aligns closely with the respective opening times of diurnally and nocturnally flowering <i>Hemerocallis</i>. The overexpression of <i>HfCOL2</i> in tobacco plants led to early flowering and prolonged flower longevity. In <i>Hemerocallis</i>, the <i>HfCOL2</i> gene plays a pivotal role not only in photoperiod-induced flowering but also in the circadian rhythm-mediated regulation of flower opening time. Due to the limited availability of plant materials exhibiting distinct flower opening rhythms, research in this area has been constrained. Identifying the key genes in the flowering pathway of <i>Hemerocallis</i> can facilitate a better understanding of the mechanisms by which plants respond to circadian rhythms.https://www.mdpi.com/2223-7747/14/13/1996<i>Hemerocallis</i>floweringcircadian<i>HfCOL</i>2
spellingShingle Chunjing Guan
Yike Gao
Ziyi Wang
Qixiang Zhang
The <i>CONSTANS-like 2</i> Gene Serves as a Pivotal Regulator of Flowering in <i>Hemerocallis</i>
Plants
<i>Hemerocallis</i>
flowering
circadian
<i>HfCOL</i>2
title The <i>CONSTANS-like 2</i> Gene Serves as a Pivotal Regulator of Flowering in <i>Hemerocallis</i>
title_full The <i>CONSTANS-like 2</i> Gene Serves as a Pivotal Regulator of Flowering in <i>Hemerocallis</i>
title_fullStr The <i>CONSTANS-like 2</i> Gene Serves as a Pivotal Regulator of Flowering in <i>Hemerocallis</i>
title_full_unstemmed The <i>CONSTANS-like 2</i> Gene Serves as a Pivotal Regulator of Flowering in <i>Hemerocallis</i>
title_short The <i>CONSTANS-like 2</i> Gene Serves as a Pivotal Regulator of Flowering in <i>Hemerocallis</i>
title_sort i constans like 2 i gene serves as a pivotal regulator of flowering in i hemerocallis i
topic <i>Hemerocallis</i>
flowering
circadian
<i>HfCOL</i>2
url https://www.mdpi.com/2223-7747/14/13/1996
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