Aug 2026· Physiologia Plantarum : An International Journal for Plant Biology· Vol 178 5, pp.
e71085
· 0 citations· 50 references
Medicine
TL;DR
It is established that CmELF4-LIKE 3 interacts with CmPIF7 to cooperatively regulate short-day-induced flowering in chrysanthemum, and offers new insights into the crosstalk between the circadian clock and light signaling pathways in plants.
Abstract
The photoperiod is a key environmental factor regulating flowering in the short-day plant chrysanthemum, and the molecular mechanisms of key genes responding to short-day conditions remain incompletely elucidated. This study focused on CmELF4-LIKE 3, a chrysanthemum homolog of the core photoperiod-sensing gene EARLY FLOWERING 4 (ELF4). CmELF4-LIKE 3 displayed circadian expression patterns under both long-day (LD) and short-day (SD) conditions, peaking 8 h after dawn, with significantly higher expression under SD than LD. The gene was highly expressed in stems and leaves, and subcellular localization confirmed its nuclear localization. Genetic transformation experiments showed that overexpression of CmELF4-LIKE 3 accelerated flower bud appearance by 3-5 days compared to the wild type, whereas RNAi lines delayed bud emergence by 4-8 days, demonstrating that CmELF4-LIKE 3 promotes flowering in chrysanthemum. Yeast two-hybrid (Y2H) and tobacco luciferase complementation (LUC) assays both verified a physical interaction between CmELF4-LIKE 3 and CmPIF7, a key component of the light signaling pathway. Quantitative real-time PCR (qRT-PCR) analysis revealed significant changes in the expression of downstream flowering-related genes CmCOL5 and CmCO in CmELF4-LIKE 3 transgenic lines. Additionally, tobacco transient LUC assays demonstrated that CmPIF7 activates the CmCOL5 promoter. In summary, this study established that CmELF4-LIKE 3 interacts with CmPIF7 to cooperatively regulate short-day-induced flowering in chrysanthemum. These findings not only provide key genetic resources for precise flowering time manipulation in chrysanthemum, but also offer new insights into the crosstalk between the circadian clock and light signaling pathways in plants.
Evidence is provided suggesting that StFKF1 influences the timing of flowering and tuber initiation, as well as the expression patterns of key regulatory genes, under long-day conditions, thereby contributing to a theoretical foundation for understanding developmental transitions in this specific environmental context.
Zefeng Zhai, Yongguang Liu, Haicai Li et al.· Molecular breeding· 0 citations
Perennial plants have evolved complex regulatory networks that allow them to perceive environmental changes and trigger adaptive growth responses. Many perennial herbs exhibit a rosette growth habit during winter, and then undergo extension growth/stem elongation growth and flowering in the following spring. However, the mechanisms underlying this seasonal transition are still not well understood. Here, using the perennial herb chrysanthemum (Chrysanthemum morifolium), we identified CmKN1, a class I KNOTTED (KN1)-like homeobox transcription factor, that mediates extension growth and flowering competence in response to prolonged chilling exposure. The rosette growth of chrysanthemum rhizomes in late autumn coincides with downregulation of CmKN1 expression. Overexpression of CmKN1 promotes premature rhizome extension growth and flowering, whereas the kn1 heterozygous mutant shows suppression of these processes. Furthermore, seasonal growth regulation involves the abscisic acid (ABA) signaling pathway. Shoot apices in the rosette state accumulate higher levels of ABA than those in the extension growth state. Notably, in response to ABA, CmKN1 expression is downregulated by CmABI5. Our results demonstrated that the CmABI5-CmKN1 module mediates extension growth and flowering competence in response to chilling, thereby facilitating the perennial growth habit of chrysanthemum.
Tianhua Jiang, Chang Luo, Chu-Qi Zhang et al.· New Phytologist· 0 citations
Tomato (Solanum lycopersicum) is classified as a day-neutral plant, whereas its wild relatives exhibit delayed flowering under long day (LD) conditions due to higher activity of the SELF-PRUNING 5G (SP5G). In Arabidopsis thaliana, CONSTANS (CO) activates FLOWERING LOCUS T (FT), a homolog of SP5G, but whether and how CO integrates with SP5G in tomato flowering was unclear. Here, we demonstrate that SlCOL1 (the tomato CO homolog) delays flowering by directly activating SP5G in a PHYTOCHROME B1 (PHYB1)-dependent manner. Importantly, genetic and molecular analyses combining a photoperiod-responsive tomato line carrying the wild SP5G allele from S. pennellii, together with SlCOL1 and flowering-pathway mutants, revealed synergistic crosstalk among the photoperiodic SlCOL1–SP5G module, age-dependent pathway (mediated mainly by the microRNA156–SlSBP module), gibberellin (GA) pathway, and SINGLE FLOWER TRUSS (SFT) pathway. Mechanistically, we show that SP5G forms a complex with miR156-targeted SlSBP13 to directly regulate SFT expression, and that GA may interfere with SP5G activity. Together, these findings revealed a coordinated network that integrates multiple flowering signals to modulate both shared and pathway-specific targets. Our findings provide a significant advance in understanding the molecular regulation of tomato flowering and offer promising avenues for breeding strategies optimized for diverse environmental conditions and latitudes.
M. H. Vicente, Gloria Serrano-Bueno, K. Pandey et al.· bioRxiv· 0 citations
Soybean (Glycine max) is a photoperiod-sensitive legume whose latitudinal adaptation depends on the precise control of flowering time and plant height. Histone demethylases of the JmjC domain-containing (JMJ) protein family have been implicated in these processes across plant species, but their specific roles in soybean remain largely unexplored. Here, we identify soybean GmJMJ19 and GmJMJ20, two closely related JMJD5/KDM8 orthologs, as master epigenetic regulators that coordinately control both photoperiodic flowering and post-flowering plant height. Both genes exhibit intrinsic, rhythmic expression peaking at ZT12, and their encoded proteins physically interact with the florigen proteins FT2a and FT5a. Loss-of-function mutants display delayed flowering under long days (LDs) and increased plant height under both LDs and short days (SDs), whereas overexpression phenocopies the mutant flowering phenotype, indicating revealing a critical dosage requirement for proper function. Mechanistically, GmJMJ19 and GmJMJ20 are recruited by the FT/FD transcriptional complex to directly activate AP1a and AP1c expression through chromatin modulation. Population genomic analyses reveal distinct selection signatures: GmJMJ19 underwent sustained directional selection during cultivation, whereas GmJMJ20 experienced an early domestication sweep with limited subsequent change. Haplotype analysis identifies coordinated latitudinal clines, with the JMJ19H1/JMJ20H1 combination predominating at high latitudes to promote early flowering and limit height, while JMJ19H2/JMJ20H2 and wild JMJ19H3/JMJ20H3 alleles prevail at low latitudes, conferring later flowering and increased height. Collectively, our findings establish GmJMJ19 and GmJMJ20 as central chromatin regulators linking florigen signaling to downstream target expression and provide valuable allelic resources for breeding regionally adapted soybean varieties across a wide range of latitudinal environments.
Xiu-Lin Liu, Cheng-Yang Song, Yuan-Yuan Cui et al.· Plant Communications· 0 citations
Abstract Anthocyanins are the primary determinants of floral pigmentation in Chrysanthemum ×morifolium, and ethylene acts as a key regulator of their biosynthesis. Although the ethylene-mediated regulatory circuitry is functionally important, its underlying mechanism in chrysanthemum has remained unclear. In this study, we identified CmMYB4 as a transcriptional repressor that directly suppresses the expression of key anthocyanin biosynthetic genes, including CmDFR (dihydroflavonol 4-reductase), CmUFGT (flavonoid 3-O-glucosyltransferase), and Cm3MaT (anthocyanin 3-O-glucoside-6″-O-malonyltransferase). Time-ordered gene co-expression network analysis comparing the transcriptomes of CmMYB4-overexpressing and control plants, together with molecular biology experimental results, further revealed CmERF3 (ethylene response factor 3) as a hierarchical upstream regulator of anthocyanin biosynthesis. Exogenous ethylene treatment induced CmERF3 expression while reducing anthocyanin accumulation. Subsequent functional characterization showed that the overexpression of CmERF3 suppresses anthocyanin biosynthesis in both tobacco and chrysanthemum by directly activating CmMYB4 and repressing CmDFR, CmUFGT, and Cm3MaT. Collectively, these findings revealed that ethylene inhibits anthocyanin biosynthesis through a CmERF3−CmMYB4−LBGs (late biosynthetic genes) regulatory module. This study not only elucidates the molecular mechanism governing ethylene-mediated anthocyanin inhibition but also provides new perspectives for the molecular engineering of ornamental traits in chrysanthemum.
Meng-Ling Li, Wen-Jing Zhao, Shuangda Li et al.· Horticulture Research· 0 citations
Flowering is a crucial process in the growth and development of plants, playing an essential role in their life cycles. Thus, research into the regulation of flowering time holds significant importance. While CmBBX7 has been identified as a flowering activator regulated by photoperiod, the molecular mechanisms underlying its regulation at the protein level remain unclear. In this study, we utilized yeast two-hybrid screening to identify two proteins that interact with CmBBX7: the phosphatase CmPP6 and the E3 ubiquitin ligase CmMIEL1. Ubiquitination assays confirmed that CmMIEL1 promotes the degradation of CmBBX7, thereby affecting its protein stability and influencing flowering. Genetic evidence indicated that both CmPP6 and CmMIEL1 delay flowering. By interacting with CmBBX7, they indirectly repress the expression of CmFTL1, which is a key flowering gene in chrysanthemum. Our findings provide preliminary evidence that ubiquitin modification affects the stability of the CmBBX7 protein and thereby regulates flowering in chrysanthemum.
Yuqing Zhu, Jinyu Jin, Yiwen Zhai et al.· Plant physiology and biochem...· 0 citations
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