title: The DELLA-CONSTANS Transcription Factor Cascade Integrates Gibberellic Acid and Photoperiod Signaling to Regulate Flowering.
abstract: Gibberellin (GA) and photoperiod pathways have recently been demonstrated to collaboratively modulate flowering under long days (LDs). However, the molecular mechanisms underlying this collaboration remain largely unclear. In this study, we found that GA-induced expression of FLOWERING LOCUS T (FT) under LDs was dependent on CONSTANS (CO), a critical transcription factor positively involved in photoperiod signaling. Mechanistic investigation revealed that DELLA proteins, a group of crucial repressors in GA signaling, physically interacted with CO. The DELLA-CO interactions repressed the transcriptional function of CO protein. Genetic analysis demonstrated that CO acts downstream of DELLA proteins to regulate flowering. Disruption of CO rescued the earlier flowering phenotype of the gai-t6 rga-t2 rgl1-1 rgl2-1 mutant (dellap), while a gain-of-function mutation in GA INSENSITIVE (GAI, a member of the DELLA gene) repressed the earlier flowering phenotype of CO-overexpressing plants. In addition, the accumulation of DELLA proteins and mRNAs was rhythmic, and REPRESSOR OF GA1-3 protein was noticeably decreased in the long-day afternoon, a time when CO protein is abundant. Collectively, these results demonstrate that the DELLA-CO cascade inhibits CO/FT-mediated flowering under LDs, which thus provide evidence to directly integrate GA and photoperiod signaling to synergistically modulate flowering under LDs.
authors.affiliation: Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan 650223, China (H.W., J.P., Y.L., D.L., Y.H., D.Y.); andUniversity of Chinese Academy of Sciences, Beijing 100049, China (H.W., J.P., Y.L., D.L.).
authors.forename: Houping
authors.initials: H
authors.lastname: Wang
authors.affiliation: Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan 650223, China (H.W., J.P., Y.L., D.L., Y.H., D.Y.); andUniversity of Chinese Academy of Sciences, Beijing 100049, China (H.W., J.P., Y.L., D.L.).
authors.forename: Jinjing
authors.initials: J
authors.lastname: Pan
authors.affiliation: Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan 650223, China (H.W., J.P., Y.L., D.L., Y.H., D.Y.); andUniversity of Chinese Academy of Sciences, Beijing 100049, China (H.W., J.P., Y.L., D.L.).
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.affiliation: Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan 650223, China (H.W., J.P., Y.L., D.L., Y.H., D.Y.); andUniversity of Chinese Academy of Sciences, Beijing 100049, China (H.W., J.P., Y.L., D.L.).
authors.forename: Dengji
authors.initials: D
authors.lastname: Lou
authors.affiliation: Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan 650223, China (H.W., J.P., Y.L., D.L., Y.H., D.Y.); andUniversity of Chinese Academy of Sciences, Beijing 100049, China (H.W., J.P., Y.L., D.L.) huyanru@xtbg.ac.cn ydq@xtbg.ac.cn.
authors.forename: Yanru
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan 650223, China (H.W., J.P., Y.L., D.L., Y.H., D.Y.); andUniversity of Chinese Academy of Sciences, Beijing 100049, China (H.W., J.P., Y.L., D.L.) huyanru@xtbg.ac.cn ydq@xtbg.ac.cn.
authors.forename: Diqiu
authors.initials: D
authors.lastname: Yu
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D035264:Flowers / Q000235:genetics* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000235:genetics* / Q000528:radiation effects; D005875:Gibberellins / Q000494:pharmacology*; D015151:Immunoblotting; D009154:Mutation; D017440:Photoperiod; D010937:Plant Growth Regulators / Q000494:pharmacology; D030821:Plants, Genetically Modified; D011485:Protein Binding; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics / Q000528:radiation effects; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C092776:CONSTANS protein, Arabidopsis; D004268:DNA-Binding Proteins; C418905:FT protein, Arabidopsis; C109555:GAI protein, Arabidopsis; D005875:Gibberellins; D010937:Plant Growth Regulators; D014157:Transcription Factors; C007842:gibberellic acid