Search Results (496)

In Lolium perenne, a novel growth habit mutant, named VIROIZ, was recovered following colchicine treatment, and it was confirmed to maintain the diploid chromosome number (2n = 2x = 14). The mutation affected the stem morphology by inducing prolific axillary shoot formation at nodal zones, resulting in a spreading growth habit that can extend to ~70 cm in width. Inheritance analysis based on single-plant evaluations in crosses with wild-type plants (F₁, n = 285; F₂, n = 380) and in selfed progeny (S₁, n = 255) consistently showed ~40% expression of the spreading phenotype, deviating from classical Mendelian ratios and indicating complex genetic control. Phenotypic selection further distinguished divergent classes: positively selected lines (C1⁺) averaged 3.90 axillary tillers per stem, whereas negatively selected lines (C1⁻) averaged only 0.22. Partial sequencing of 11 candidate genes implicated in shoot architecture, covering 40–90% of full-length DNA, did not provide a conclusive explanation for the altered stem growth. Notably, a single point mutation was observed in CRT3 (an endoplasmic reticulum chaperone that interacts with brassinosteroid signaling) highlighting it as a primary target for future studies. Cytological analysis of meiosis in F₁ hybrids between VIROIZ and wild-type plants revealed irregular chromosome pairing with persistent univalents (2–4 per cell), supporting the presence of structural chromosomal rearrangements that may disrupt gene organization and function in VIROIZ. The non-Mendelian segregation of the spreading phenotype, together with the observed meiotic irregularities, suggests that the mutation affects regulatory genes responsive to hormonal signals controlling axillary meristem initiation. The mutant represents a valuable resource for turf-type L. perenne breeding and for studying hormonal regulation of shoot morphogenesis in Poaceae. Full article

The ABCB subfamily, a subset transporter of the ATP-binding cassette (ABC) superfamily, is vital for various plant life processes, especially in the transport of polar auxin and brassinosteroids. Although ABCB transporters have been characterized in diverse plant species, their specific functions in wheat remain largely unexplored. In this study, we identified 99 TaABCB members in wheat and categorized them into four groups based on their conserved domains and phylogenetic relationships. These members were found to be unevenly distributed across all 21 wheat chromosomes. We conducted a comprehensive genome-wide analysis encompassing gene structure, protein motifs, gene duplication events, collinearity, and cis-acting elements. Transcriptome analysis revealed that different TaABCB members displayed distinct expression patterns under phosphate starvation stress. Notably, we discovered that TaABCB7 might play a role in regulating wheat’s phosphate starvation. Crucially, we pinpointed an elite haplotype, H001, of the candidate gene TaABCB7, which has been progressively selected and employed in wheat breeding improvement programs. Overall, this study enhances our comprehensive understanding of TaABCB members and offers a potential gene resource for molecular marker-assisted selection breeding in wheat. Full article

Melatonin (MT), an antioxidant and growth regulator, interacts with almost all phytohormones, but the molecular mechanisms of these interactions are poorly understood. Using mRNA sequencing (mRNA-seq) technology, we analysed the global regulation of MT-induced expression of genes involved in metabolism, signalling and responses to major phytohormones under prolonged high-intensity light (HL) stress. Plants respond to MT through the activation of auxin and brassinosteroid (BS) response genes, which were identified among the enriched categories of differentially expressed genes (DEGs) with increased expression, and the suppression of abscisic acid and ethylene signalling and response genes, which were among the enriched downregulated categories. MT also suppressed growth-inhibiting genes involved in jasmonic acid (JA) and salicylic acid (SA) signalling and response and activated genes encoding the growth-promoting hormones gibberellins and cytokinins (CKs), which is consistent with the role of MT in stress alleviation. However, the expression of some unique genes, which are positively or negatively modulated by stress, was reinforced by MT treatment, illustrating the extraordinary type of regulation that enhances the action of specific hormone-mediated mechanisms. The study of signal integration between MT and hormones with the involvement of signalling mutants revealed that some interactions are regulated at the transcriptional level and require the activity of relevant signalling pathways. Disruption of CAND2 completely abolished melatonin-dependent activation of the mitogen-activated protein kinases MAP3K17 and MKK7, suggesting that the MAP3K17-MKK7 module is an important player in the MT-triggered MAPK pathway, acting downstream of CAND2. Full article

Cold stress reduces horticultural crop yield and postharvest quality by disrupting membrane fluidity, redox equilibrium, and the cell wall structure. This results in chilling injury, tissue softening, and loss of color. Long noncoding RNAs (lncRNAs) have emerged as key integrators of plant cold signaling pathways. LncRNAs mediate the interaction between calcium signaling systems and transcriptional cascades while coordinating hormone signaling networks, including those involving abscisic acid, jasmonic acid, ethylene, salicylic acid, and brassinosteroids. LncRNAs influence gene regulation through chromatin-based guidance, sequestration of repressive complexes, natural antisense transcriptional interference, microRNA-centered competing endogenous RNA networks, and control of RNA splicing, stability, localization, and translation. Studies in horticultural species revealed that cold-responsive lncRNAs regulate processes essential for fruit firmness, antioxidant levels, and shelf-life, including lipid modification, reactive oxygen species balance, and cell wall or cuticle remodeling. This review aims to summarize tissue- and developmental stage-specific expression patterns and highlight experimental approaches to validate RNA function, including gene editing, transcript recovery, advanced sequencing, and analysis of protein-RNA interactions. Integrating these results will facilitate the development of precise molecular markers and nodes of regulatory networks that increase cold tolerance, and improve the quality of horticultural crops. Full article

The BRI1-EMS suppressor/Brassinazole-resistant (BES/BZR) transcription factors (TFs) act as regulators of the Brassinosteroid (BR) signaling pathway and play key roles in modulating plant growth, development, and abiotic stress tolerance. However, the function of BES/BZR TFs remains unknown in warm-season turfgrass species. In this study, ZjBZR2, a BES/BZR TF in Zoysia japonica was identified and shared the closest evolutionary relationship with OsBZR2 from Oryza sativa. ZjBZR2 was a nuclear-localized protein and had transcriptional activation activity. ZjBZR2 was predominantly expressed in roots, stems, and lamina joints, and could be significantly induced by BR treatment and osmotic stresses including PEG and salinity. ZjBZR2-overexpressing rice lines increased leaf angle compared with wild-type plants. Furthermore, overexpression of ZjBZR2 enhanced osmotic stress (PEG and salt) tolerance which is associated with the upregulation of stress-responsive and ROS-scavenging genes. These findings provide the first functional characterization of ZjBZR2 in rice and offer excellent genetic resources for the improvement of turfgrass cultivars. Full article

Brassinosteroid analogs with heterocyclic rings in the side chain are interesting because important biological activity has been shown by these compounds. Thus, herein, five 23-24-dinorcholane BR analogs with a heterocyclic ester function at C-22 were synthesized and fully characterized by different spectroscopic techniques. The acylation reaction at C-22, which is a key synthetic step, was carried out by two different methods, namely acylation with heterocyclic acid chlorides and Steglich esterification reaction. In both cases, the acyl derivatives were obtained with good yields. Additionally, a preliminary molecular docking study of BRI1–BAK1 complexes formed by these analogs and brassinolide was performed to estimate what their biological activity would be. Results indicate that the complex formed by the analog 36, which has an indole group in the side chain, within the active site of BRI1–BAK1 is more stable than that formed by brassinolide. Additionally, molecular docking of a derivative having a benzoate function at C-22 and a F atom in the ortho position, 23, shows a similar pose and interactions at the active site but the highest binding energy. As 23 has shown similar activity to brassinolide in the Rice Lamina Inclination Test, it is expected that 36 will also exhibit similar behavior. Full article

Brassinosteroids (BRs) are essential regulators of plant development and stress responses, but the distinct contributions of BR biosynthesis and signaling to hormonal crosstalk remain poorly defined. Here, we investigated the effects of the BR biosynthesis inhibitor brassinazole (BRZ) and the BR-insensitive mutant bri1-6 on endogenous phytohormone profiles in Arabidopsis thaliana. Using multivariate analysis and targeted hormone quantification, we show that BRZ treatment and BRI1 disruption alter hormone balance through partially overlapping but mechanistically distinct pathways. Principal component analysis (PCA) and hierarchical clustering revealed that BRZ and the bri1-6 mutation do not phenocopy each other and that BRZ still alters hormone profiles even in the bri1-6 mutant, suggesting potential BRI1-independent effects. Both BRZ treatment and the bri1-6 mutation tend to influence cytokinins and auxin conjugates divergently. On the contrary, their effects on stress-related hormones converge: BRZ decreases salicylic acid (SA), jasmonic acid (JA), and abscisic acid (ABA) in the WT leaves; similarly, bri1-6 mutants show reduced SA, JA, and ABA. These results indicate that BR biosynthesis and BRI1-mediated perception may contribute independently to hormonal reprogramming, with BRZ eliciting additional effects, possibly via metabolic feedback, compensatory signaling, or off-target action. Hormone correlation analyses revealed conserved co-regulation clusters that reflect underlying regulatory modules. Altogether, our findings provide evidence for a partial uncoupling of BR levels and BR signaling and illustrate how BR pathways intersect with broader hormone networks to coordinate growth and stress responses. Full article

Excess sodium in soil disrupts ionic balance and limits water uptake, negatively affecting growth and stolon production in strawberry plants. This study assessed the effects of chitosan (CTS), brassinosteroids (BRs), and thidiazuron (TDZ) on stolon performance and physiological responses of strawberry cv. ‘Portola’ under saline conditions. A greenhouse experiment included seven treatments: CTS, BRs, CTS + BRs combinations, TDZ, and an untreated control. Foliar applications were used to evaluate impacts on nutrient uptake, photosynthetic pigments, oxidative stress, and stolon production. BRs alone [2.53 × 10⁻⁶ μM] significantly increased crown diameter (+43%), stolon number (+65%), stolon length (+4%), and daughter plant formation (+8%), while reducing leaf sodium by 60% and improving Mg²⁺/Na⁺ and K⁺/Na⁺ ratios. The CTS + BRs combination enhanced phenolic content and produced the heaviest first daughter plants (6.1 g). TDZ, however, resulted in weaker stolons, lower chlorophyll a content, and reduced K⁺/Na⁺ ratios, suggesting a need for dose optimization. Overall, BRs, alone or with CTS, improved salt tolerance and stolon propagation through enhanced ion regulation, photosynthesis, and antioxidant defenses. These findings advance understanding of how biostimulants modulate metal ion homeostasis, antioxidant signaling, and growth in salt-sensitive crops, offering strategies to mitigate salinity stress in strawberry cultivation. Full article

Lycoris longituba produces a single flower bearing six tepals. The double-petaled phenotype of L. longituba has gained significant interest in China due to its ornamental and commercial value in tourism industries. This double-petal phenotype, characterized by stamen petalization, shows improved esthetic characteristics compared with conventional single-petal form. However, the molecular mechanisms underlying this floral trait remain largely undefined. In this study, RNA-based comparative transcriptomic analysis was performed between single- and double-petaled flowers of L. longituba at the fully opened flower stage. Approximately 13,848 differentially expressed genes (DEGs) were identified (6528 upregulated and 7320 downregulated genes). Functional annotation through Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses revealed several DEGs potentially involved in double-petal development. Six candidate genes, including the hub genes LlbHLH49, LlNAC1, LlSEP, LlTIFY, and LlAGL11, were identified based on DEG functional annotation and weighted gene co-expression network analysis (WGCNA). Transcription factors responsive to phytohormonal signaling were found to play a pivotal role in modulating double-petal development. Specifically, 123 DEGs were involved in phytohormone biosynthesis and signal transduction pathways, including those associated with auxin, cytokinin, gibberellin, ethylene, brassinosteroid, and jasmonic acid. Moreover, 521 transcription factors (TFs) were identified, including members of the MYB, WRKY, AP2/ERF, and MADS-box families. These results improve the current understanding of the genetic regulation of the double tepal trait in L. longituba and offer a base for future molecular breeding strategies to enhance ornamental characteristics. Full article

Plant growth regulators (PGRs) are widely used to enhance table grape quality, yet cultivar-specific responses and microstructural outcomes remain insufficiently resolved. We evaluated five PGRs—gibberellic acid (GA₃), 24-epibrassinolide (EBR), forchlorfenuron (CPPU), thidiazuron (TDZ), and streptomycin (SM)—in ‘Shine Muscat’ and ‘Red Muscat of Alexandria’. Twelve combinations were applied at full bloom (D0) and 14 days post-anthesis (D14), and morphological, physiological, and histological traits were monitored over 104 days. In ‘Shine Muscat’, GA₃ + TDZ and GA₃ + CPPU achieved nearly 100% seedlessness, while CPPU and TDZ markedly increased berry weight and size via cortical expansion. GA₃ increased berry weight but caused rachis thickening and reduced total soluble solids (TSS). EBR at concentrations ≥ 0.2 mg L⁻¹ inhibited berry growth, and SM reduced berry size and weight. Histology showed that TDZ and CPPU enlarged cortical area and epidermal thickness, potentially strengthening pericarp robustness, whereas GA₃ enlarged vascular bundle area. ‘Red Muscat of Alexandria’ showed generally weaker responses, reflecting differences between Vitis vinifera and hybrid backgrounds. These results demonstrate that combinatorial PGR strategies can be tailored to optimize berry development and quality through coordinated regulation of growth, metabolism, and microstructure. TDZ and CPPU exhibit strong production potential for enlargement, whereas GA₃ and EBR require careful dose optimization to balance benefits and quality risks. Full article

Grain shape is a critical determinant of rice yield, quality, and market value. Recent advances in molecular biology, genomics, and systems biology have revealed a complex regulatory network governing grain development, integrating genetic loci, plant hormone signaling, transcriptional regulation, protein ubiquitination, epigenetic modifications, and environmental cues. This review summarizes key genetic components such as QTLs, transcription factors, and hormone pathways—including auxin, cytokinin, gibberellin, brassinosteroids, and abscisic acid—that influence seed size through regulation of cell division, expansion, and nutrient allocation. The roles of the ubiquitin–proteasome system, miRNAs, lncRNAs, and chromatin remodeling are also discussed, highlighting their importance in fine-tuning grain development. Furthermore, we examine environmental factors that impact grain filling and size, including temperature, light, and nutrient availability. We also explore cutting-edge breeding strategies such as gene editing, functional marker development, and wild germplasm utilization, along with the integration of multi-omics platforms like RiceAtlas to enable intelligent and ecological zone-specific precision breeding. Finally, challenges such as pleiotropy and non-additive gene interactions are discussed, and future directions are proposed to enhance grain shape improvement for yield stability and food security. Full article

Somatic embryogenesis (SE) is a crucial strategy for in vitro regeneration in woody plants, yet its efficiency is affected by multiple factors, and the underlying regulatory mechanisms remain insufficiently understood. In this study, callus tissues from two Liriodendron sino-americanum genotypes involving different hybrid combinations, ON-LoS and TN-LoS, were treated with varying concentrations (0, 0.005, 0.01, 0.05 mg/L) of exogenous zeatin (ZT) to evaluate its regulatory effect on SE. Treatment with 0.01 mg/L ZT significantly promoted SE in ON-LoS but suppressed it in TN-LoS, indicating that ZT elicited divergent regulatory effects on SE between the two genotypes. To explore the molecular basis of this divergence, transcriptome analysis was conducted at the early stage of SE. Differentially expressed genes (DEGs) were significantly enriched in hormone signaling, particularly in the cytokinin (CK) and brassinosteroid (BR) signaling pathways, as well as biosynthetic and redox-related pathways. In particular, given the established role of cell cycle-related gene CYCD3 (Lchi20922) in promoting cell division, CYCD3 was markedly upregulated by ZT in ON-LoS but downregulated in TN-LoS. These results indicate that ZT regulates SE efficiency through differential modulation of CYCD3 expression in distinct genotypes. This study enhances our understanding of the molecular basis of SE regulation in Liriodendron sino-americanum and offers a theoretical framework for improving regeneration efficiency in woody plants. Full article

Herein, a new series of 3-DT analogs with benzoylated groups at C-23 are synthesized and characterized. The benzoylated groups carry the same substituents in the ortho- or para-positions. Thus, the effect of structure on activity, measured using the rice lamina inclination test (RLIT) and the bean second-internode assay (BSI), is evaluated. The RLIT results indicate that a benzoylate function at C-22 induces a strong increase in activity that depends on the position and nature of the substituent in the phenyl ring. For example, an analog with an -OAc group in the ortho-position is the most active derivative, and its activity is like that of brassinolide. A relative index is calculated using brassinolide as a positive control to compare the RLIT results with those reported previously. This analysis allows for the conclusion that benzoylated derivatives with a hydroxyl group at C-3 are much more active than the corresponding analogs with a carbonyl group in this position, and one extra alcohol group in the alkyl chain decreases RLIT activity. Finally, the results obtained with the BSI are clearly different to those obtained in the RLIT bioassay. Therefore, the application of any activity–structure relationship will always be dependent on the bioassay used to determine activity. Full article

The increasing demand for sustainable alternatives to synthetic agrochemicals underscores the need for novel, naturally derived plant growth regulators (PGRs) with high specificity and minimal environmental impact. In this study, we propose agavenin (AG), a steroidal saponin from Agave species, as a promising candidate and evaluate its potential role in plant growth regulation through a comprehensive in silico approach. Using molecular docking, molecular dynamics simulations, ADME profiling, and FTIR spectroscopy, we analyzed the interaction of AG with three key protein receptors (KPRs) that regulate major hormonal pathways: GA3Ox2 (gibberellin), IAA7 (auxin), and BRI1 (brassinosteroid). AG showed strong and stable binding to GA3Ox2 and IAA7, with affinities comparable to their endogenous ligands, while exhibiting low interaction with BRI1—suggesting receptor selectivity. Molecular dynamics confirmed the stability of AG–GA3Ox2 and AG–IAA7 complexes over 100 ns, and ADME profiling highlighted favorable properties for bioavailability and transport. Collectively, these findings indicate that AG could function as a selective, receptor-targeted modulator of gibberellin and auxin signaling pathways. Beyond demonstrating the molecular basis of AG’s bioactivity, this work establishes a computational foundation for its future experimental validation and potential development as a sustainable, naturally derived growth regulator for plant biotechnology and agriculture. Full article

Jasmonates (JAs) are crucial phytohormones governing plant growth and defense against stresses. This review synthesizes the intricate molecular mechanisms underlying JA crosstalk with key hormones: auxin (AU), gibberellin (GA), abscisic acid (ABA), ethylene (ET), brassinosteroids (BRs), strigolactones (SLs), and salicylic acid (SA). We focus on interactions during development and stress adaptation, highlighting how these range from synergistic (e.g., JA-ABA/ET in defense, JA-AU in root growth) to antagonistic (e.g., JA-SA in pathogen response, JA-GA/BRs in growth processes). Central to this crosstalk are key regulatory nodes like the MYC2 transcription factor and JAZ repressor proteins, which integrate signals through transcription factor networks, targeted protein degradation, and post-translational modifications. By elucidating these molecular pathways, our review establishes a framework for understanding the complex regulatory logic of hormone interactions. Furthermore, it offers insights for the strategic engineering of hormone signaling (e.g., modulating JAZ stability or MYC2 activity) to enhance crop resilience to environmental challenges. Full article