Bud dormancy release (BDR) is a critical adaptive process that determines spring bud break, flowering time, and yield stability in perennial crops. However, its regulatory mechanisms remain unclear. This study investigated the physiological and molecular basis of BDR in herbaceous peony (Paeonia lactiflora), an important perennial ornamental and oil crop. Morphological observations confirmed a gradual release from endodormancy, accompanied by continuous shoot apical meristem (SAM) differentiation. Integrative full-length transcriptomic and physiological analyses revealed that carbohydrate metabolism, plant hormone signal transduction, and environmental adaptation are enriched key pathways during BDR. WGCNA analysis identified two key modules (MEred and MEgreen), with the MADS-box APETALA1 (AP1)/FRUITFULL (FUL) subfamily gene PlFUL emerging as a central hub gene associated with BDR, a role that has rarely been reported in bud dormancy. Silencing PlFUL significantly delayed bud break, confirming its positive role in regulating BDR. RNA sequencing analyses suggested that PlFUL may promote BDR through hormonal regulation, carbohydrate metabolism, and the PlDAM-PlSOC1 module. Further comprehensive analyses revealed that PlFUL directly binds to the promoters of PlDAM and PlSOC1, thereby repressing PlDAM but activating PlSOC1 transcription. Together, these findings shed light on the regulatory role of PlFUL in BDR and provide useful information for optimizing chilling requirement (CR) in perennial crop breeding.

Wetland irises are highly valued for their vibrant flowers and strong adaptability, making them important ornamental plants with broad applications in landscaping. However, their cultivation is often constrained by inefficient propagation. The application of plant growth regulators (PGRs) in wetland irises remains limited. This study systematically examined the effects of different concentrations of 6-benzylaminopurine (6-BA; 1,000 and 2,000 mg/L), and prohexadione-Ca (PC; 500 and 1,000 mg/L) on key growth parameters of three wetland iris species: Iris ensata, Iris ensata var. variegata, and Iris sanguinea. Specifically, the study focuses on evaluating the impacts of these PGRs on bud number, plant height, rhizome diameter increment, rhizome weight, and flowering performance. Quantitative analyses of the physiological and morphological responses of these species to PGR treatments revealed distinct, species-specific responses to PGR treatments. Low concentrations of PC increased bud number by up to 0.75 and flower number by 0.47 per plant in I. ensata, while high concentrations of both regulators significantly reduced plant height and rhizome enlargement, particularly in Iris ensata var. variegata and I. sanguinea. These findings provide critical insights for optimizing cultivation practices of wetland irises and also contribute to both theoretical knowledge and practical guidelines for leveraging PGRs to improve the ornamental and functional traits of these plants in landscape applications.

The DOF transcription factors regulating plant bud dormancy were novelly identified. A representative member, PlOBP4, was first experimentally verified to promote bud elongation. Herbaceous peony (Paeonia lactiflora) is a world-renowned ornamental flower mainly cultivated in temperate regions. However, insufficient winter chilling accumulation may limit bud endodormancy release (BER) due to climate change or when grown at lower latitudes or elevations. Understanding the regulatory mechanisms of endodormancy release will help develop new cultivars adapted to warm winter conditions, advancing the application of herbaceous peony in subtropical and even tropical areas. The role of DNA-BINDING WITH ONE FINGER (DOF) TF family members in the regulation of bud dormancy remains limited. In this study, a bioinformatics analysis of the DOF family in P. lactiflora ‘Hang Baishao’ (a subtropical low-chilling-requirement cultivar) was performed using the full-length transcriptome sequencing data collected during a whole winter and early spring. A total of 15 DOF family members were identified and were phylogenetically classified into four subgroups. Expression profiles of some PlDOFs were correlated with bud endodormancy acquisition, BER, release of ecodormancy, and inducing break. A PlOBP4 with a 906 bp coding sequence, which is highly expressed in the BER stage, was identified and cloned. Subcellular localization confirmed that PlOBP4 was nuclear-localized. Silencing PlOBP4 in buds during the endodormancy induction period significantly reduced bud length after sprouting, indicating that PlOBP4 may promote bud elongation in P. lactiflora ‘Hang Baishao’. This relatively rare study in regulating bud dormancy/budbreak enriches the knowledge regarding the role of DOF TFs and may further aid in breeding cultivars with short endodormancy duration (low chilling requirement) and facilitate the cultivation of herbaceous peony in subtropical or even tropical regions.

High-temperature stress severely limits the cultivation and ornamental quality of herbaceous peony, especially in low-latitude regions. The objective of this study was to reveal the potential mechanism involved in regulation of jasmonates on herbaceous peony heat tolerance through crosstalk between phytohormones and the reactive oxygen species (ROS) scavenging system. The study found that exogenous methyl jasmonate (MeJA) significantly improved thermotolerance of the low-latitude cultivar ‘Hang Baishao’ by enhancing antioxidase activities and modulating endogenous phytohormone levels. The MeJA-treated group exhibited markedly higher ratios of MeJA to zeatin riboside (ZR), gibberellic acid (GA3), brassinolide (BR), and indole-3-acetic acid (IAA) compared with the control group; catalase (CAT) and superoxide dismutase (SOD) activities were significantly elevated relative to hydrogen peroxide (H2O2) content, with both ratios peaking at 36 h post-heat treatment. Transcriptomic results revealed that MeJA reshaped the expression of genes involved in jasmonic acid (JA) signaling and ROS scavenging, such as FAD4, MED25, and JAZ2 and CSD2/3, FSD1, and CAT3. Four modules including the hub genes CIPK5/6, WRKY19/40 and CYPs were identified from the weighted gene co-expression network analysis (WGCNA), which may be key players in coordinating JA signaling and antioxidant defense. This study demonstrates that MeJA enhanced herbaceous peony thermotolerance by orchestrating a regulatory network involving phytohormonal crosstalk and activation of the ROS scavenging system, and offers candidate genes for future exploration of function and interactions.

Abstract Terpene synthases (TPSs) are key drivers of terpenoid diversity in plants, yet the diversity and mechanisms driving their diversification in gymnosperms remain poorly understood. Through comparative genomic analyses of 16 representative land plant species, we demonstrate that tandem duplication (TD) plays an important role in the expansion of gymnosperm-specific TPS-d subfamily. These TD-generated TPS-d genes exhibit elevated sequence variability and markedly increased tissue specificity (τ) compared with conserved primary-metabolic TPS-c and TPS-e/f genes, indicating rapid functional and regulatory divergence following duplication. Together, our results propose a comprehensive evolutionary framework that illustrates how TD, sequence divergence, and expression diversification collectively shape TPS-d gene evolution in gymnosperms, providing new insights into lineage-specific terpenoid profiles and ecological adaptation in gymnosperms.

Herbaceous peony is a globally-renowned ornamental plant. Extreme winter conditions can severely damage the underground buds and crowns, and hinder subsequent bud break and growth of herbaceous peony, although it has a certain degree of cold tolerance. This study offers new insights into the cold tolerance of herbaceous peony by comparing two cultivars of contrasting provenances and tolerances to cold. Physiological observation, transcriptome sequencing, and gene expression analysis were performed on overwintering crown buds exposed to freezing conditions in Harbin. The two cultivars demonstrated relatively significant morphological and physiological differences in response to cold stress. Specifically, HL exhibited superior morphological traits, including more stems (4.30 vs 3.47) and flowers (12.67 vs 5.87) per plant, as well as significantly higher soluble sugar content (e.g., 280 mg/g FW vs 210 mg/g FW in January). Transcriptome results show that various expressed genes were in connection with starch and sucrose metabolism, plant-pathogen interactions, and phytohormone signaling pathways. The co-expression analysis identified and visualized the key genes in the two modules, ME black and ME yellowgreen. Integrating physiological changes with expression of genes, several key genes were identified, such as XERO1, LTI65, NADP-ME4, WRKY39, and ASA2, which are probably involved in the cold-stress response, and thus deserve further exploration in gene function and interaction. This study provides new insight into the cold-tolerance of herbaceous peony and paves the way for its future studies, and also contributes to breeding strong cold-resistant cultivars of herbaceous peony in the high-latitude regions with harsh winters.

Under global climate warming, plants evolve unique growth and developmental strategies to cope with frequent abiotic stresses. The plant-specific DNA-BINDING WITH ONE FINGER (DOF) transcription factors (TFs) originated in green algae and are phylogenetically divided into four subfamilies (A, B, C, D), governing plant growth development and stress adaptation. Subfamily B mainly regulates vegetative growth, subfamily C is predominantly involved in seed development and vegetative growth, and subfamily D1 (CYCLING DOF FACTOR, CDF) participates extensively in vegetative growth, flowering, and stress responses. Given emerging studies on DOF functions, a comprehensive review integrating recent advances, especially in seed dormancy, reproductive development and stress tolerance remains lacking. This review integrates current advances in the multifaceted roles of the DOF family, including regulating seed germination, vegetative growth, reproductive development and leaf senescence, as well as coordinating adaptive responses to various abiotic stresses.

Iris japonica, an evergreen ornamental species known for its beautiful flowers and year-round evergreen foliage, is difficult to genetically manipulate due to the lack of an efficient genetic transformation system. This limitation hinders the functional verification of key genes in I. japonica. To address this, a Virus-Induced Gene Silencing (VIGS) system based on Tobacco rattle virus (TRV) was developed, enabling efficient, transient gene silencing in I. japonica. In this system, the phytoene desaturase (PDS) gene, a common reporter gene used for VIGS, was selected to assess the silencing efficiency. The recombinant vector pTRV2-IjPDS was used to infect I. japonica plants. The PDS gene silencing resulted in distinct photobleaching symptoms, demonstrating the successful silencing of the target gene. The presence of the TRV vector was verified by using a GFP-tagged pTRV2-GFP vector, and GFP expression was detected using fluorescence visualization under ultraviolet (UV) light and confirmed by laser confocal microscopy. Real-time PCR was used to quantify the reduction in IjPDS gene expression, confirming the successful silencing. The study further optimized the VIGS system by evaluating the impact of seedling ages on silencing efficiency, identifying one-year-old seedlings as the most effective for gene silencing (36.67%). This TRV-based VIGS system provides a robust tool for functional gene analysis in I. japonica and offers a new approach to studying the rules of key genes in its biological processes, with potential applications in ornamental plant breeding and genomics research.

Sugar metabolism is commonly implicated as crucial in the transition between growth and cessation during winter; however, its exact role remains elusive. The evergreen iris (Iris japonica) ceases growth in winter without entering endodormancy, yet it continues to sustain sugar metabolism and transport throughout the season. Here, we elucidate the mechanisms underlying the sugar-mediated growth transition-the shift between growth and cessation-in I. japonica through integrative physiological and transcriptional analyses. We investigated the function and transcriptional regulation of FLOWERING LOCUS C-LIKE 1 (IjFLCL1) and demonstrated that IjFLCL1 promotes growth resumption. Additionally, ALPHA-AMYLASE-LIKE 3 (IjAMY3), a starch degradation gene downstream of IjFLCL1, inhibits growth in I. japonica, potentially by modulating endogenous starch granule dynamics. Moreover, sugar-induced transcription factor SUGAR SIGNALING IN BARLEY 2 (IjSUSIBA2) activates IjFLCL1 expression. Conversely, IjSUSIBA2 directly represses the well-known dormancy mediator SHORT VEGETATIVE PHASE-LIKE 2 (IjSVL2), which in turn inhibits IjFLCL1 expression. IjSUSIBA2 may be induced by both exogenous and endogenous sugar signals, subsequently regulating downstream genes. Overall, our results suggest sugar molecules might serve as both signals and energy to regulate growth transition through IjFLCL1-mediated novel pathways. These insights carry valuable implications for the cultivation and breeding of perennials to withstand the challenges posed by climate change.

The MIKC-type MADS-box (MIKC) gene family is essential for controlling various plant developmental processes, including flowering time and dormancy transitions. Although the MIKC gene family has been widely studied across different plants, its characterization and functional study in herbaceous peony remain limited. In this study, 19 Paeonia lactiflora Pall. MIKC-type (PlMIKC) genes were identified from the transcriptome of a low-chilling requirement Paeonia lactiflora Pall. cultivar ‘Hang Baishao’. These MIKC genes were categorized into seven clades: six were classified as MIKCC-type, including FUL/AP1, DAM, PI, AGL18, AGL12, AG, and SOC1, and one, AGL30, was classified as MIKC*-type. Notably, the FLC clade genes were absent in Paeonia lactiflora Pall. The PlMIKC genes were predominantly localized to the nucleus, and their sequences contained highly conserved MADS and K-domains. Phylogenetic analysis demonstrated that PlMIKC genes share a strong evolutionary affinity with the MIKC genes from grapevine (Vitis vinifera) and poplar (Populus trichocarpa). A low-temperature-induced bud dormancy transition (BDT) experiment revealed that PlMIKC genes, such as PlFUL and PlDAM, were highly expressed during dormancy maintenance, while PlSOC1, PlAGL12, and PlAGL30 were upregulated during BDT. Additionally, the transient overexpression of PlSOC1 in ‘Hang Baishao’ significantly accelerated BDT and promoted bud break, suggesting that SOC1, traditionally linked to flowering regulation, also plays a key role in dormancy transition. Since limited literature on the MIKC gene family is currently available in herbaceous peony, this study expands the knowledge of the MIKC genes in Paeonia lactiflora Pall. and offers valuable insights into the molecular regulation of bud dormancy in response to low temperatures.

Yellow flag (Iris pseudacorus L.), belonging to the genus of Iris, is a herbaceous flower with significant ornamental, ecological, and economic values. Nevertheless, its limitations include single flower color, short ornamental duration, and long breeding cycles, which impede its widespread landscape use and the development of new cultivars. In this study, an efficient and environmentally friendly strategy for embryogenic callus induction and plant regeneration of yellow flag was constructed. The results demonstrate the importance of utilizing tender embryos as explants to establish this environmentally friendly in vitro regeneration system. Notably, we achieved a contamination rate of 0

High temperature (HT) is a major environmental stress that severely inhibits potato (Solanum tuberosum L.) tuberisation and yield. Heat shock transcription factors (Hsfs) are pivotal in plant thermotolerance, yet their roles in potato remain unclear. Here, we demonstrate that overexpression of StHsfA2, a rapidly HT-responsive HSF family member, enhances thermotolerance and mitigates yield loss in transgenic potato under HT conditions. We reveal that StHsfA2 upregulates StSP6A expression by binding to the heat shock element-like motifs in its promoter. StSP6A encodes a homologue of FLOWERING LOCUS T that is critical for initiating tuber formation. Intriguingly, we found that StHsfA2 physically interacts with the StSP6A protein, which in turn inhibits StHsfA2-mediated StSP6A upregulation. However, HT stress attenuates the StHsfA2-StSP6A interaction. Thus, a negative feedback loop modulates StSP6A regulation by StHsfA2 under HT. In summary, our study shows that StHsfA2 is a key regulator of thermotolerance in potato plants. Its overexpression enhances heat resistance and could boost tuber yield, making it a promising candidate gene for countering yield loss amid global warming.

Lycoris Herb., a perennial bulbous flower belonging to the Amaryllidaceae family, is distributed extensively in East, Central China, as well as in Asian regions such as Japan and South Korea (Ji and Meerow 2000). As a result of its diverse flower colors, graceful leaf arrangement, strong adaptability, and multifunctional values in terms of ornamental, medicinal, and ecological significance, Lycoris is used for ecological enhancement, urban landscaping, and agricultural purposes (Zhao et al. 2024). Lycoris plants offer a diverse array of flower shapes and colors on upright scapes (Luo et al. 2009). They serve dual purposes as garden groundcover and cut flower materials (Wang et al. 2008). Lycoris plants have a strong adaptability to environmental changes and a low maintenance cost. In Japan, the United States, and European countries, the commercial production of Lycoris cut flowers has been well-established for a long time (Lin and Lee 1993; Zhao et al. 2022). Notably, certain varieties have also been cultivated and sold in small quantities in China, including Yunnan, Shanghai, Nanjing, Hangzhou, and Taiwan (Yu et al. 2006; Zhao et al. 2021), and they are gradually gaining popularity

The transition from bud endodormancy to ecodormancy is triggered by environmental cues, particularly low temperatures. However, the mechanism underlying bud dormancy transition (BDT) is largely unknown. Here, we identified a low-temperature-responsive, MADS-box family SUPPRESSOR OF OVEREXPRESSION OF CO1 (PlSOC1) under both natural and controlled low temperatures, which promotes BDT and confers low chilling requirement trait of herbaceous peony (Paeonia lactiflora). A novel transcription factor, DNA-binding One Zinc Finger (DOF) family OBF BINDING PROTEIN 1 (PlOBP1), was found to bind the AAAAG motif in the PlSOC1 promoter, acting as a negative regulator of BDT. PlOBP1 acts together with Dormancy Associated MADS-box (PlDAM) protein to enhance the transinhibitory effect of PlSOC1. Further gibberellic acid (GA) treatment showed that exogenous GA can replace long-term chilling to promote BDT, likely by inhibiting the expression of PlOBP1 while inducing the expression of PlSOC1. The elevated PlSOC1 forms a complex with PlDAM and inhibits PlDAM activity, further releasing the inhibition on PlSOC1, thereby amplifying PlSOC1 and triggering BDT. Our findings provide mechanistic insights into low-temperature-mediated GA regulation of BDT and reveal a novel role of DOF protein PlOBP1 and its interactions with MADS-box family members in bud dormancy regulation.

Lilies are economically important monocots known for their ornamental flowers, bulbs, and large genomes. The absence of their genomic information has impeded evolutionary studies and genome-based breeding efforts. Here, we present reference genomes for Lilium sargentiae (lily, 35.66 Gb) and Gloriosa superba (flame lily, 5.09 Gb). The giant lily genome is shaped by recent long terminal repeat retroelements. Phylogenetic analysis reveals diverse, independent origins of lily cultivars. Gene families involved in sucrose and starch metabolism are significantly expanded in the lily genome. Key homologs of XTH22, SOC1, and AP1/FUL-like genes regulate the development, bud growth transition, and floral bud growth transition of lily bulbs. Colchicine biosynthetic gene clusters are identified in G. superba but are absent in L. sargentiae, highlighting independent colchicine evolution in Colchicaceae. These genomic insights enhance understanding of Liliales evolution, providing a foundation for future breeding and molecular research. Lilies are perennial plants with ornamental flowers and large genomes. The authors assemble genomes of two Liliales species, analyze lily phylogeny, flower and stem development (bulbs in lilies, rhizomes in flame lilies), bulb growth transitions, and colchicine biosynthesis.

Reblooming is a highly desirable trait in ornamental plants as it extends the flowering period and enhances horticultural value. This study investigated genetic relationships of 17 bearded iris cultivars, comprising nine reblooming, and eight once-flowering cultivars. Transcriptome-wide screening identified 29,800 Simple Sequence Repeat (SSR) loci from 100,391 unigenes, with an occurrence frequency of 29.68%. Dinucleotide repeats were the most abundant (69.10%), predominantly AG/CT and AT/AT motifs, while trinucleotide repeats accounted for 30.90%, mainly AAG/CTT and AGG/CCT motifs. From 110 primers designed based on these loci, eight highly polymorphic primers were selected, detecting 43 alleles with polymorphic information content (PIC) values ranging from 0.5072 to 0.6986 (average 0.6228). These markers effectively distinguished between reblooming and once-flowering cultivars, enabling the construction of molecular fingerprints and a cluster dendrogram for the 17 cultivars. Association analysis revealed that one SSR marker (P2S19) significantly correlated with the reblooming trait. Together, these findings provides valuable insights for understanding reblooming regulation and facilitate the molecular breeding of reblooming iris cultivars.

Iris, the largest genus within the Iridaceae family, is renowned for its striking flower diversity and high ornamental value. With applications extending across landscape design, traditional medicine, and ecological restoration, the genus holds considerable economic and ecological significance (Li et al. 2022; Singab et al. 2016). Among this genus, I. japonica Thunb. is widely distributed across China and stands out as the earliest blooming species in the Hangzhou region, typically flowering in early spring (Zhao et al. 2000). This species is notable for its profuse terminal racemose inflorescences (Thunberg et al. 1794), evergreen sword-shaped foliage, and a very short winter dormancy period without endodormancy (Li et al. 2022). Furthermore, I. japonica exhibits abundant natural variation, providing a rich source of traits for breeding.

China is rich in medicinal–ornamental plants with multifunctional uses, making a significant contribution to global landscaping, environmental beautification, and the health industry. In the post-pandemic era, there is an increasing focus on improving living environments and enhancing immune health, leading to a growing demand for the development and utilization of these plant resources. Resource evaluation is fundamental to their widespread application in landscaping, commercial production, germplasm innovation, and sustainable utilization. However, current research is limited, and there is an absence of a comprehensive evaluation system. The evaluation of these plants, particularly endangered wild species, is vital for biodiversity conservation, rational resource utilization, and breeding. This study proposes a resource evaluation model based on three key aspects: ecological adaptability, medicinal value, and ornamental value. It also reviews commonly employed research methods, such as the scoring method, analytic hierarchy process (AHP), and fuzzy mathematics. Looking forward, we highlight the importance of establishing fundamental evaluation indicators, integrating new technologies, leveraging big data, and strengthening evaluations for germplasm innovation and the protection of these multifunctional medicinal–ornamental plant resources in China.

Gene function verification is a crucial step in studying the molecular mechanisms regulating various plant life activities. However, a stable and efficient homologous genetic transgenic system for herbaceous peonies has not been established. In this study, using virus-induced gene silencing technology (VIGS), a highly efficient homologous transient verification system with distinctive advantages was proposed, which not only achieves true “intact-plant” infiltration but also minimizes the operation. One-year-old roots of the representative species, Paeonia lactiflora Pall., were used as the materials; prechilling (4 °C) treatment for 3–5 weeks was applied as a critical precondition for P. lactiflora to acquire a certain chilling accumulation. A dormancy-related gene named HOMEOBOX PROTEIN 31 (PlHB31), believed to negatively regulate bud endodormancy release (BER), was chosen as the target gene in this study. GFP fluorescence was detected in directly infiltrated and newly developed roots and buds; the transgenic plantlets exhibited remarkably earlier budbreak, and PlHB31 was significantly downregulated in silenced plantlets. This study established a homologous transient silencing system featuring intact-plant infiltration and minimized manipulation for gene function research, and also offers technical support and serves as a theoretical basis for gene function discovery in numerous other geophytes.