Search Results (73)

The rapid development of viticulture in subtropical regions represents a significant achievement in China’s table grape industry over the last two decades. However, insufficient winter chilling in these areas often leads to inadequate dormancy, which compromises nutrient translocation and storage in grapevines. Insufficient chilling accumulation results in asynchronous budbreak and reduced cane quality. In this study, ‘Shine Muscat’ grapevines were used to systematically evaluate how different defoliant agents affect budbreak characteristics from the perspective of nutrient translocation and storage. The results indicated that applications of ethephon or urea alone, as well as their combinations with boric acid, yielded unstable effects, often causing primary bud necrosis, decreased flower formation rates, and phytotoxicity. In contrast, the combination of lime sulfur and boric acid exhibited a remarkable synergistic effect, significantly promoting dry matter and starch accumulation in canes while enhancing the budbreak speed, uniformity, and flower cluster formation rate. Further experiments with varying concentrations of lime sulfur combined with 0.2% boric acid revealed that utilizing 2% lime sulfur in this combination produced the most pronounced effects, achieving the highest dormancy-breaking efficacy under conventional cultivation conditions. This treatment was used for the first time to produce a second crop during off-season cultivation. The dual effects of dormancy release and bud promotion achieved via this approach represent a reliable solution in high-quality and efficient grape production in subtropical regions. Full article

Global warming leads to premature dormancy release and untimely flowering in southern highbush blueberry during winter, resulting in chilling injury and yield losses. However, effective strategies to delay flowering by modulating dormancy progression without compromising fruit quality remain lacking. This study demonstrated through field trials that spraying 1 mg/mL ethephon (ETH) during the early endodormancy stage effectively delayed dormancy release and reduced the bud break rate of spring shoots by approximately 33.92% relative to the control, with no adverse effects on fruit quality. The treatment also reduces sucrose content in floral buds, a change potentially associated with dormancy maintenance. To explore the molecular basis of this process, we examined two ethylene-responsive transcription factors, VcERF112 and VcERF115, previously identified in our laboratory. Their expression was rapidly upregulated following ETH treatment. Heterologous expression of either gene in Arabidopsis delayed both seed germination and flowering, suggesting a conserved growth-suppressive function. Dual-luciferase reporter assays confirmed that VcERF112 and VcERF115 bind to the T2 region (−2310 to −1595 bp) of the VcBRC1 (VcBRANCHED1) promoter and enhance its expression. In contrast, sucrose treatment suppressed VcBRC1 expression. Collectively, these results propose that ethylene may sustain bud dormancy through a coordinated mechanism that operates independently of the classic abscisic acid (ABA)/gibberellins (GA) balance, a relationship not addressed in this study. This mechanism involves the induction of VcERF112/115 to activate VcBRC1, coupled with the reduction in sucrose levels to alleviate its repressive effect on VcBRC1. These findings provide new molecular insights into the ethylene-mediated regulatory network underlying bud dormancy in blueberry. Full article

The excessively concentrated ripening period of mulberries causes seasonal surplus. Fruit mulberry (Morus spp.) exhibits the unique trait of “simultaneous flowering and leaf flushing”, rendering budburst timing closely correlated with fruit ripening time. Thus, deciphering the molecular mechanism underlying winter bud dormancy maintenance in fruit mulberry is urgently needed. Herein, an F₁ hybrid population comprising 337 individuals, derived from Morus wittiorum (♀) and ‘322’ (♂), was utilized as research material. Through Bulked Segregant Analysis Sequencing (BSA-Seq), we successfully mapped a dormancy-associated QTL interval designated as LB (Late Burst), spanning 9,990,001–11,990,000 bp on Chromosome 13. Integrating Weighted Gene Co-expression Network Analysis (WGCNA) results, MaSVP was identified as a candidate gene within this interval. Virus-induced gene silencing (VIGS) of MaSVP in winter buds of Morus wittiorum significantly accelerated budburst compared to the control, demonstrating that MaSVP represses winter bud dormancy release and plays a crucial role in regulating dormancy maintenance in fruit mulberry. Dynamic expression profiling of dormancy-related genes revealed that the transcript levels of MaSVP, MaSAPK3, MaCASL2, and MaPYR8 were significantly downregulated (Tukey’s test, p < 0.05) as budburst approached, whereas those of MaFT and MaGA20ox1-D were significantly upregulated (Tukey’s test, p < 0.05). These results indicate that winter bud dormancy maintenance in Morus wittiorum is associated with abscisic acid (ABA) and gibberellin (GA) metabolism. Collectively, this study provides critical insights into the biological basis of winter bud dormancy maintenance in fruit mulberry and offers valuable genetic resources for breeding late-maturing cultivars. Full article

Global warming has increasingly reduced winter chill accumulation in traditional fruit-growing regions, disrupting dormancy release and bloom synchrony in deciduous fruit crops such as peach (Prunus persica). To evaluate adaptation potential under subtropical conditions, a three-year field study was conducted in central Taiwan using two low-chill cultivars, ‘Tainung No.4 Ruby’ (~100 chilling units, CU) and ‘Tainung No. 7 HongLing’ (~77 CU). Our results demonstrate that both cultivars produced long shoots (>34 nodes), completed vegetative growth by October, and reached natural leaf fall by mid-November. Nonlinear Gompertz and Logistic models accurately described shoot elongation dynamics and growth cessation. Flowering began in mid-January for ‘Tainung No. 7 HongLing’ and mid-February for ‘Tainung No. 4 Ruby’. Seasonal chill accumulation strongly influenced the onset of flower budbreak between apical and basal buds: in the milder 2023–2024 winter (~120 CU), apical–basal onset lags were wider (22 days in ‘Tainung No. 7 HongLing’), whereas in the colder 2024–2025 winter (~280 CU), these lags shortened (14 days). Notably, ‘Tainung No. 4 Ruby’ maintained a consistent apical–basal onset lag between seasons, indicating greater positional stability under variable chilling. Field-estimated CU thresholds for flower budbreak exceeded the reported chilling requirements, suggesting reduced chilling efficiency under fluctuating subtropical winter temperatures. These results demonstrate that integrating shoot growth, leaf fall timing, and chill–heat accumulation provides a phenology-informed framework for cultivar selection and orchard scheduling, thereby enhancing climate resilience of peach production in warm-winter regions. Full article

In this study, Hedychium coccineum tetraploid plants and octaploid plants induced by colchicine were used as materials. The ploidy levels were precisely identified by combining root tip squash and flow cytometry analyses, and the differences between plants of different ploidy levels were systematically investigated at cytological, morphological, and molecular levels. The results showed that the highest polyploid induction efficiency was achieved when callus tissues were treated with 0.1 g/L colchicine for 4 days. The fluorescence peak value of the induced plants was twice that of the tetraploids, confirming their octaploid status. Compared with tetraploids, octaploid plants exhibited almost no apparent dormancy period, significantly slower growth, earlier flowering, and notably smaller inflorescences. Morphologically, they showed a dwarf phenotype characterized by narrower and lighter-colored leaves, fewer leaves per shoot, shorter internodes, and wider leaf angles, along with enhanced stress tolerance. Cytological observation revealed that cell area in internode tissues at the bud and seedling stages was generally larger in tetraploids than in octaploids, suggesting a reduction in cell size following genome duplication. Furthermore, transcriptome comparison between tetraploids and octaploids identified HcPCNA1 as a candidate gene closely associated with plant height. Functional validation showed that overexpression of HcPCNA1 in Arabidopsis thaliana significantly increased plant height, whereas silencing of HcPCNA1 in H. coccineum via Virus-induced gene silencing (VIGS) resulted in a distinct dwarf phenotype with smaller leaves. Cytological and molecular evidence together indicate that HcPCNA1 may influence plant height in H. coccineum through its role in promoting cell division and elongation. This finding provides new insights into the molecular mechanisms underlying plant architecture development in polyploid species. Full article

Michelia ‘Xin’ is an evergreen rare ornamental tree species that undergoes FBD only once but blooms twice a year. However, the molecular mechanisms controlling its FBD process remain largely unknown. This study characterized the FBD process and delved into the key molecular regulatory mechanisms through transcriptomic and metabolomic analyses of developing flower buds. FBD in Michelia ‘Xin’ was characterized into five stages, including vegetative (T1), floral meristem transition (T2), tepal primordia differentiation (T3), stamen primordia differentiation (T4), and pistil primordia differentiation (T5). Analyses revealed a stage-specific metabolic and transcriptional regulation of FBD, with increasing numbers of differential metabolites and a decreasing number of DEGs from T1 to T5. Most phytohormone and transcription factor-related DEGs were highly induced from T2. The down-regulation of dormancy-associated protein homologs and CONSTANS-LIKE proteins associated with significant induction of flowering-promoting factor, CLAVATA3, trichome birefringence-like, and GRAVITROPIC IN THE LIGHT proteins was essential for the induction and reproductive organs’ development. Porphyrin biosynthesis, chlorophyll a-b binding proteins, DNA replication, flavonoid biosynthesis, and starch and sucrose metabolism were also significantly induced from T2. Key pivotal candidate genes were screened out. Our results provide fundamental resources for dissecting the molecular network regulating FBD and molecular-assisted flowering control in Michelia ‘Xin’. Full article

Pear (Pyrus pyrifolia) is an important deciduous fruit tree that requires a specific period of low-temperature accumulation to trigger spring flowering. The warmer winter caused by global warming has led to insufficient winter chilling, disrupting floral initiation and significantly reducing pear yields in Southern China. In this study, we integrated targeted phytohormone metabolomics, full-length transcriptomics, and proteomics to explore the regulatory mechanisms of dormancy in ‘Mixue’, a pear cultivar with an extremely low chilling requirement. Comparative analyses across the multi-omics datasets revealed 30 differentially abundant phytohormone metabolites (DPMs), 2597 differentially expressed proteins (DEPs), and 7722 differentially expressed genes (DEGs). Integrated proteomic and transcriptomic expression clustering analysis identified five members of the dormancy-associated MADS-box (DAM) gene family among dormancy-specific differentially expressed proteins (DEPs) and differentially expressed genes (DEGs). Phytohormone correlation analysis and cis-regulatory element analysis suggest that DAM genes may mediate dormancy progression by responding to abscisic acid (ABA), gibberellin (GA), and salicylic acid (SA). A dormancy-associated transcriptional regulatory network centered on DAM genes and phytohormone signaling revealed 35 transcription factors (TFs): 19 TFs appear to directly regulate the expression of DAM genes, 18 TFs are transcriptionally regulated by DAM genes, and two TFs exhibit bidirectional regulatory interactions with DAM. Within this regulatory network, we identified a novel pathway involving REVEILLE 6 (RVE6), DAM, and CONSTANS-LIKE 8 (COL8), which might play a critical role in regulating bud dormancy in the ‘Mixue’ low-chilling pear cultivar. Furthermore, lncRNAs ONT.19912.1 and ONT.20662.7 exhibit potential cis-regulatory interactions with DAM1/2/3. This study expands the DAM-mediated transcriptional regulatory network associated with bud dormancy, providing new insights into its molecular regulatory mechanisms in pear and establishing a theoretical framework for future investigations into bud dormancy control. Full article

Pear buds exhibit inherent dormancy, during which carbohydrates play a pivotal role in dormancy release and germination. In this study, Pyrus pyrifolia ‘Cuiguan’ was employed as the experimental material to investigate the molecular mechanisms underlying flower bud dormancy release. The results revealed that the dynamic balance between starch and soluble sugar is critical for promoting dormancy release and germination in P. pyrifolia ‘Cuiguan’ flower buds. Through transcriptomic and proteomic profiling, a total of 4035 differentially expressed genes (DEGs) and 1596 differentially expressed proteins (DEPs) were identified, which were predominantly associated with carbohydrate metabolism, particularly sugar metabolism pathways. Their changes were coordinately regulated at both transcriptional and translational levels. Key structural genes involved in maltose and sucrose biosynthesis, including BAM (LOC103949270), AAM (LOC125479337, LOC103940334, and LOC103941903), SPS (LOC125475683), and INV (LOC125478747), were significantly upregulated during the germination stage, facilitating flower bud sprouting. Integrated multi-omic analysis demonstrated that starch–sugar interconversion may govern dormancy release and sustained bud growth by modulating sugar metabolism-related genes and proteins. These findings provide novel insights into the molecular mechanisms of carbohydrate biosynthesis and associated protein regulation during dormancy release and development of P. pyrifolia ‘Cuiguan’ under natural conditions. Full article

The tree peony holds significant historical, cultural, and practical value. P. ostii is extensively cultivated in China, where it represents the primary oil-producing variety of tree peonies. However, the current nutrient supplementation system for P. ostii lacks an empirical basis, resulting in frequent wastage of nutrients during daily production. In this study, varying ratios and quantities of nitrogen, phosphorus, and potassium were administered to P. ostii at distinct phases of its annual growth cycle, specifically during the bud sprouting, post-flowering, and dormancy periods. The results showed that during the bud sprouting period, the plants treated with a high nitrogen and potassium ratio (a high N&K ratio, N–P–K = 35%–20%–35%) had better flowering traits than those treated with a high phosphorus ratio (a high P ratio, N–P–K = 20%–35%–20%). Under the standard application amount, plants treated with a high N&K ratio outperformed those treated with a high P ratio in terms of flowering duration, net photosynthetic rate, and flowering biomass, with increases of 20.9%, 10.7%, and 32.9%, respectively. During the post-flowering period, all plants died when treated with 1.5 × standard amounts of the above ratios. At this period, the all-high ratio with N–P–K = 45%–45%–45% resulted in a 70.4% increase in fruit set, a 43.8% increase in seed number, and a 153.8% increase in biomass compared with the high N&K ratio. During the dormancy period, nutrient supplementation with the standard amount of P led to higher increases in ground diameter and biomass. Therefore, in subsequent tree peony production, particular attention should be paid to nutrient supplementation during the post-flowering period to prevent excessive fertilizer application and safeguard the plants’ normal growth and development. Full article

Gibberellin (GA₃) plays a crucial role in regulating the flowering time of tree peony (Paeonia suffruticosa Andr.). However, its function on flower opening after dormancy release remains unclear, and its molecular mechanism need further study. We investigated the effects of exogenous GA₃ treatments at 800 mg/L, 900 mg/L, and 1000 mg/L on the flowering process of five-year-old peony plants (‘Luhehong’) under greenhouse conditions. Our results showed that exogenous GA₃ significantly accelerated the flower opening process. Specifically, flower buds treated with 800 mg/L and 900 mg/L GA₃ bloomed after 42 and 45 days, respectively. In contrast, all flower buds treated with 1000 mg/L GA₃ aborted, while only one flower bud in the control group bloomed after 56 days. Furthermore, analysis of endogenous hormone levels revealed that GA₃ treatment rapidly increased endogenous GA₃ levels, decreased ABA levels, and gradually increased IAA levels. Transcriptomic analysis of flower buds released from dormancy following GA₃ treatment identified multiple key genes involved in the flower opening process of peony. Notably, members of the C2H2, C3H, ERF, bHLH, MYB, bZIP, NAC, and WRKY families showed significant differential expression. Moreover, several key genes involved in GA₃, ABA, and IAA hormone signaling pathways were also differentially expressed. Our findings suggested that an appropriate concentration of exogenous GA₃ treatment could accelerate the flower opening process in tree peony through multiple pathways, which would provide valuable insights into the molecular mechanisms underlying the gibberellin-mediated flower opening process in tree peony. Full article

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 MIKC^C-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. Full article

The flowering and fruiting of sweet cherry (Prunus avium L.) depend on precise synchronization with seasonal events. During harsh autumn and winter conditions, floral buds enter dormancy to protect and prepare for the productive season. Dormancy release occurs after exposure to genotype-specific chilling temperatures, an event in which epigenetic reprogramming triggers further metabolic and gene expression activation. Similarly, several Arabidopsis ecotypes require chilling (vernalization) to transition from vegetative to floral states. At vernalization’s end, the decrease in the repressor complex formed by SHORT VEGETATIVE PHASE (SVP) and FLOWERING LOCUS C (FLC) allows FLOWERING LOCUS T (FT) to induce flowering. However, this alone does not fully explain the process. MicroRNAs (miRNAs) play a crucial role in gene regulation during plant development and environmental interactions, and miR396’s role during flower development and vernalization has been described in some plant species, although not for sweet cherry dormancy. We used ‘Regina’, a high-chill sweet cherry variety, to identify candidate small RNA molecules throughout dormancy, resulting in the detection of miR396. The transcript expression levels of the putative miRNA target genes were evaluated through quantitative PCR analyses of dormant buds. Additionally, an artificial sweet cherry miR396 was used to transform Arabidopsis Edi-0, a vernalization-requiring ecotype. Ectopic expression of this artificial molecule partially mirrored the effect on target genes observed in dormant buds and, more importantly, led to vernalization-independent flowering. Artificial miR396 expression also resulted in decreased FLC and increased SVP and FT transcript levels. These results could pave the way for future studies on the involvement of miR396 in the regulation of dormancy and flowering, with potential applications in improving crop resilience and productivity. Full article

Dormancy breakers are widely employed in regions with an insufficient chill accumulation to enhance floral bud break in sweet cherry production. Dormex (HC) has not been authorized in Europe and many other countries due to its detrimental effects on human health (carcinogenic) and the environment. This situation has increased the demand for alternative chemicals to HC. The current study was conducted in an orchard of 5-year-old ‘Royal Tioga^®’ sweet cherry trees (Prunus avium L.) grafted on MaxMa 14 rootstocks in the Karayusuflu Village (at an altitude of 50 m), Adana, a Mediterranean city in Türkiye. Levante (LV) and HC were applied approximately 30 days before the anticipated dormancy break of the buds. Chill accumulation was quantified monthly during the 2023–2024 winter season using the chilling hours below 7.2 °C (467 h) and chill units (280 CUs). This study evaluated the effects of dormancy breakers on hormonal changes in floral buds, focusing specifically on gibberellic acid (GA₃) and abscisic acid (ABA). Also, their impact on fruit set and quality parameters was assessed. The findings revealed that the LV and HC applications reduced the ABA content in flower buds during the dormancy period compared to the control. LV significantly improved bud break rates (56.8%) and fruit set (85.2%) while positively influencing the fruit quality parameters and yield. No significant differences between the LV and HC treatments were observed regarding average fruit weight (8.8–8.4 g) and yield values (3.7–3.5 kg tree⁻¹). These results suggest LV as an alternative to HC for early-season cherry production in warm climates. Full article

Dormancy release is an important process for improving the quality of cut-flower lily production and promoting the factory production of lily bulbs. However, the regulatory mechanisms of microRNAs (miRNAs) and their target genes during the dormancy release of lily remain elusive. Anatomy, transcriptomic, molecular biology, and transient transformation techniques involving subcellular localization were applied in our study. There were significant results showing that 0.1 mM riboflavin promoted dormancy release and floral bud differentiation and influenced the flowering time of the Lilium ‘Siberia’. Moreover, some differentially expressed miRNAs and their targets (miR395-y: LoAPS1, miR529-z: LoSPL14, miR396-y: LoCFDP1, miR1863-z: LoFBA3, miR399-y: LoDIT1, and miR11525-z: Lopgm) were identified and predicted. Exogenous riboflavin may activate primary metabolic processes and promote dormancy release in Lilium ‘Siberia’ bulbs. Furthermore, riboflavin upregulated genes related to the riboflavin pathway, H3K4me3 methylation, dormancy control, and the flowering pathway and downregulated dormancy maintenance genes. Moreover, riboflavin promoted endogenous riboflavin and acetyl-CoA accumulation. LoPurple acid phosphatase17 (LoPAP17), a pivotal gene of the riboflavin metabolism pathway, was subsequently cloned. LoPAP17 was most closely related to the orthologous genes of Acorus calamus, Asparagus officinalis, and Musa acuminata. The LoPAP17 protein was subcellularly located in the nucleus. Our study revealed that miRNAs and their target genes might regulate the primary metabolic pathway, promote the accumulation of endogenous riboflavin and acetyl-CoA, and affect protein acetylation during the riboflavin-promoted release of dormancy and flower bud differentiation in the Lilium Oriental hybrid ‘Siberia’. Full article

During the dormant period of peach trees in winter, flower buds exhibit weak cold resistance and are susceptible to freezing at low temperatures. Understanding the physiological and molecular mechanisms underlying the response of local peach buds to low-temperature adversity is crucial for ensuring normal flowering, fruiting, and yield. In this study, the experimental materials included the conventional cultivar ‘Xia cui’ (XC) and the cold-resistant local resources ‘Ding jiaba’ (DJB) peach buds. The antioxidant enzyme activity, levels of malondialdehyde (MDA), proline (Pro), and hydrogen peroxide content (H₂O₂) were determined in peach buds at different dormancy periods. Transcriptome sequencing was performed at three dormancy stages: the dormancy entry stage (FD), deep dormancy release stage (MD), and dormancy release stage (RD). Additionally, transcriptome sequencing was conducted to analyze gene expression profiles during these stages. Our findings revealed that compared with XC cultivars, DJB peach buds exhibited decreased MDA and H₂O₂ contents but increased superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities as well as Pro content during the dormancy period. These findings suggest that cold-resistant cultivars possess significantly stronger antioxidant capacity than conventional cultivars under low-temperature stress. A total of 10,168 differential genes were annotated through transcriptome sequencing. Among them, 4975 were up-regulated while 5193 were down-regulated. The differentially expressed genes associated with low-temperature response in peach buds are primarily enriched in plant hormone signal transduction pathway and phenylpropane synthesis pathway. Key differentially expressed genes related to cold resistance include ARF2, GH3, and SAPK2, and differentially expressed transcription factors mainly belong to the AP2/ERF-ERF, bHLH, and C2H2 families. This study provides a theoretical foundation for understanding the key genes involved. Full article