Search Results (378)

Double-flowered cultivars are generally considered more attractive than single-flowered varieties in ornamental plants. The AP2/ERF transcription factors superfamily plays pivotal roles in plant development, including floral organ formation. Here, a total of 248 AP2/ERF genes were identified in the genome of L. speciosa, and these genes were unevenly distributed on the 24 chromosomes. Phylogenetic analysis classified LsAP2/ERF genes into five distinct groups; the ERF subfamily was the largest, whereas the AP2 subfamily was associated with floral development. Gene duplication events contributed to the expansion of LsAP2/ERF family members, with segmental duplication identified as the primary contributor. Promoter cis-element analysis revealed an abundance of light-responsive and hormone-responsive elements. Spatiotemporal expression profiling showed that core AP2 subfamily members (LsAP2/ERF4/9/10/13/219) exhibited distinct expression patterns during flower bud development. Moreover, heterologous overexpression of LsAP2/ERF10 in tobacco resulted in transgenic lines with altered petal morphology, supporting its potential functional involvement in floral development. This study provides comprehensive characterization of the AP2/ERF family in L. speciosa, laying the foundation for elucidating its molecular mechanisms in floral morphogenesis. Full article

Adventitious root (AR) formation is critical for the successful establishment and survival of rose (Rosa hybrida) cuttings. SCARECROW-LIKE (SCL) genes are known to regulate plant growth and development; however, their functions in rose AR formation remain poorly understood. In this study, the rooting rate of rose cuttings declined, whereas AR number increased with increasing concentrations of exogenous indole-3-butyric acid (IBA) and N-1-naphthylphthalamic acid (NPA). Most of the 36 identified RhSCL genes were significantly up-regulated during AR formation. Notably, the expression level of RhSCL3 and RhSCL33 was positively associated with AR formation under low concentrations of exogenous IBA and NPA. Both genes were expressed at higher levels in roots than in other organs and encoded nuclear-localized proteins with transcriptional activation activity. Heterologous expression of RhSCL3 and RhSCL33 in tobacco increased primary root length under exogenous IBA treatment, enhanced AR number and length, and promoted dry matter accumulation, accompanied by increased starch degradation and soluble sugar production. Compared with wild-type plants (WT), transgenic plants showed reduced indole-3-acetic acid (IAA) levels, more pronounced changes in gibberellic acid (GA₃) content, and higher activities of superoxide dismutase (SOD), peroxidase (POD), polyphenol oxidase (PPO), catalase (CAT), and indole-3-acetic acid oxidase (IAAO). These findings suggest that overexpression of RhSCL3 and RhSCL33 facilitates rooting under low-auxin conditions, and RhSCL33 acting earlier during AR development, and RhSCL3 functioning mainly at later stages. This regulatory module may provide useful genetic targets for improving vegetative propagation efficiency in rose and other horticultural or crop species. Full article

Cold stress severely impairs grapevine (Vitis vinifera L.) growth, development, and productivity, necessitating the identification of elite cold-resistance genes for breeding tolerant cultivars. Chinese wild grape germplasm, particularly the endemic Vitis yeshanensis ‘Yanshan’ ecotype, represents a valuable reservoir of stress-resistance alleles with exceptional cold hardiness. In this study, we isolated an R2R3-MYB transcription factor gene VyMYB24 from ‘Yanshan’ grape and systematically characterized its function in low-temperature responses. VyMYB24 expression was rapidly and strongly induced by cold stress, with transcript levels peaking at 12 h after treatment. Heterologous overexpression of VyMYB24 in transgenic tobacco (Nicotiana benthamiana) induced pronounced architectural changes. Transgenic plants exhibited a dwarf and compact stature with enhanced lateral branching, thickened stems, and robust root systems. In addition, anatomical analysis revealed markedly increased xylem and phloem thickness. Under cold stress, transgenic lines outperformed wild-type plants, with reduced wilting, lower water loss, and improved survival and recovery rates. Physiologically, VyMYB24 activated the antioxidant defense system, elevated the activities of key reactive oxygen species (ROS)-scavenging enzymes, suppressed H₂O₂ and superoxide accumulation, and reduced malondialdehyde content and electrolyte leakage, thereby preserving cellular homeostasis. This study provides functional evidence for the positive regulatory role of VyMYB24 in cold tolerance via heterologous expression, underscores the genetic value of ‘Yanshan’ grape germplasm, and lays a preliminary foundation for improving crop stress resistance through the utilization of native wild germplasm genes. Full article

Sorghum seeds accumulate substantial amounts of condensed tannins (CTs), which are also referred to as proanthocyanidins (PAs), contributing to their characteristic astringent taste. Flavan-3-ol polymers, known as PAs, are sequestered within plant vacuoles and become catalytically activated via laccase enzymes. However, the biological roles and regulatory pathways of laccases in sorghum are still largely unclear. Here, integrated transcriptomic and metabolomic profiling of developing sorghum seeds identified 7942 differentially expressed genes between low- and high-CT lines, with Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment revealing flavonoid biosynthesis as a key pathway; weighted gene co-expression network analysis (WGCNA) further pinpointed SbLAC14 as a hub gene within the module most strongly correlated with CT content. We then examined its regulation by microRNA397 (SbmiR397-5p). Dual-luciferase assays confirmed the binding of SbmiR397-5p to SbLAC14 in co-transformed tobacco leaves. Overexpressing SbLAC14 in transgenic Arabidopsis significantly increased CT accumulation while decreasing catechin and epicatechin levels. Furthermore, transgenic plants overexpressing miR397 (OEmiR397-5p) exhibited reduced CT content, accompanied by a lightening of seed color. Conversely, transgenic lines overexpressing a miR397-insensitive laccase transcript exhibited a reversed phenotypic outcome. Our findings indicate that SbmiR397-5p negatively regulates the expression of SbLAC14 in relation to CT biosynthesis, identifying it as a potential target for manipulating CT metabolism in sorghum. Those results provide a genetic entry point for metabolic engineering and breeding efforts aimed at modulating grain phenolic profiles. Full article

Serotonin N-acetyltransferase (SNAT) is pivotal to melatonin biosynthesis, catalyzing either serotonin into N-acetylserotonin or 5-methoxytryptamine (5-MT) into melatonin. Many SNAT genes have been cloned from a wide range of organisms, including animals and plants, but none has been reported in the model streptophyte green alga Chara braunii. Here, we found one archaeal CbSNAT homologue in the C. braunii genome, which showed 28% and 27% amino acid homology with human Naa50 and rice SNAT3, respectively. The CbSNAT gene, encoding a 172-amino acid protein, was expressed and purified in Escherichia coli. The recombinant CbSNAT protein exhibited SNAT enzyme activity toward serotonin (K_m = 293 μM) and 5-MT (K_m = 28 μM), and was located in the cytoplasm of tobacco cells, similar to other archaeal SNAT homolog proteins. To assess whether CbSNAT was functionally coupled to melatonin biosynthesis, CbSNAT was overexpressed in rice. Transgenic CbSNAT-overexpressing rice seedlings showed enhanced melatonin synthesis and resistance to both cadmium and the herbicide butafenacil. The cadmium resistance was due to the increased expression of chaperone genes such as BIP3, BIP4, and BIP5, whereas the butafenacil resistance resulted from increased expression of protoporphyrinogen oxidase 1, a target gene of butafenacil, via the transcriptional regulatory effects of melatonin. The discovery of a CbSNAT gene in C. braunii opens a new avenue for its use as a genetic resource in the development of crops exhibiting stress resistance to toxic compounds found in modern agriculture. Full article

Drought and soil salinization severely limit the productivity of global agriculture and forestry, highlighting the urgency of identifying stress-resistant genes for molecular breeding. B-box (BBX) proteins constitute a class of zinc finger transcription factors that play significant roles in plant abiotic stress responses. Amorpha fruticosa (A. fruticosa) is a perennial woody plant with exceptional adaptability to harsh environments, serving as a valuable resource for mining stress-resistant genes. In this study, the AfBBX gene was cloned from A. fruticosa, and its function in stress tolerance was systematically analyzed. Bioinformatics analysis confirmed that AfBBX contains a conserved ZnF-BBOX domain and shares functional conservation with the BBX protein family. Quantitative real-time polymerase chain reaction (qRT-PCR) revealed tissue-specific expression of AfBBX, with the highest expression in stems and the lowest in young leaves. Furthermore, AfBBX expression was dynamically regulated in roots and leaves of A. fruticosa under treatments of 5 μM ABA (drought mimic), H₂O₂ (oxidative stress), 10% PEG600 (osmotic stress), and NaHCO₃ (alkaline stress). Transgenic tobacco lines overexpressing AfBBX showed enhanced tolerance to osmotic and salt–alkali stresses at both germination and seedling stages. Meanwhile, compared to wild-type (WT) tobacco, transgenic lines exhibited higher germination rates, longer root lengths, and greater fresh weights under stress conditions. Under natural drought and salt–alkali stresses, transgenic tobacco maintained higher chlorophyll fluorescence intensity (Fv/Fm values), elevated activities of antioxidant enzymes [superoxide dismutase (SOD)], and reduced malondialdehyde (MDA) content. In conclusion, AfBBX enhances stress tolerance by mitigating photosystem damage, increasing reactive oxygen species (ROS) scavenging capacity, and reducing membrane lipid peroxidation. The findings from this study provide novel insights into the molecular mechanism underlying AfBBX-mediated stress resistance and offer valuable genetic resources for breeding drought- and salt-tolerant crops and forest trees. Full article

Cotton is recognized as the primary source of essential natural fibers for the global textile industry, supporting its sustainability and development. However, adverse environmental conditions such as drought severely constrain cotton production; thus, developing stress-tolerant cultivars via molecular breeding is essential for maintaining yield stability. Here, a comprehensive functional dissection was conducted on GhGA2ox15, a gibberellin 2-oxidase gene derived from Gossypium hirsutum L. This gene encodes a key catabolic enzyme implicated in the deactivation of endogenous bioactive GAs and the modulation of stress adaptation. We characterized GhGA2ox15, a GA2ox gene from upland cotton that modulates endogenous bioactive GA levels and abiotic stress tolerance. Bioinformatics and sequence analyses confirmed that GhGA2ox15 is a canonical C₂₀-GA2ox subfamily member, with conserved DIOX_N and 2OG-FeII_Oxy domains and marked similarity to orthologs in Arabidopsis and rice. Tobacco subcellular localization assays indicated that GhGA2ox15 resides in both the nucleus and the cytoplasm. In transgenic Arabidopsis and Oryza sativa lines, GhGA2ox15 overexpression was shown to increase drought tolerance, while virus-induced gene silencing (VIGS) of GhGA2ox15 yielded significantly compromised drought resistance. Physiological assays linked GhGA2ox15 silencing to impaired reactive oxygen species (ROS) detoxification. The suppressed lines displayed markedly lower antioxidant enzyme activities, concomitant ROS accumulation in leaves, and attenuated transcription of drought-responsive marker genes. Our findings delineate the mechanistic role of GhGA2ox15 in drought adaptation and highlight its potential utility in breeding drought-tolerant cotton. Full article

Low-temperature stress significantly limits plant growth, development, and productivity, posing a major environmental constraint. The potato (Solanum tuberosum L.) is particularly vulnerable to low temperatures, underscoring the crucial need to enhance cold tolerance in potato breeding efforts for sustainable production. Basic leucine zipper (bZIP) transcription factors serve as central regulators of plant developmental processes and stress responses; however, their functional role in cold tolerance in tetraploid potato remains poorly understood. Here, we report a systematic characterization of the bZIP gene family in tetraploid potato and provide preliminary evidence that StbZIP104 enhances plant cold tolerance. A total of 191 StbZIP genes were identified and classified into 11 subfamilies, exhibiting uneven chromosomal distribution and expansion primarily driven by whole-genome and segmental duplication. Promoter cis-element analysis, together with GO and KEGG enrichment analyses, indicated that StbZIP genes are broadly associated with hormone signaling, stress responses, signal transduction, and environmental adaptation. Expression profiling under low-temperature treatment revealed eight cold-inducible StbZIP genes (log₂FC ≥ 1 and FDR < 0.05), among which StbZIP104 was strongly induced (log₂FC ≥ 2) and showed 5.36-fold higher expression in highly cold-resistant cultivars than in cold-sensitive cultivars. Subcellular localization confirmed that StbZIP104 is a nuclear-localized protein. Functional validation confirmed that overexpressing StbZIP104 notably improved cold tolerance in transgenic Samsun NN tobacco (Nicotiana tabacum cv. Samsun NN). This was supported by heightened superoxide dismutase and peroxidase activities, increased levels of soluble protein and soluble sugars, and decreased malondialdehyde content compared to the wild type under cold stress. This study establishes a basis for the functional characterization of the bZIP gene family in tetraploid potato and serves as a theoretical reference for understanding the mechanisms that govern cold tolerance in this species. Full article

The role of endogenous salicylic acid (SA), a major signaling molecule, was addressed in relation to the waterlogging (WL) stress response, including redox homeostasis and senescence. Wild-type and salicylate hydroxylase-expressing (NahG) tobacco plants were studied to reveal the stress-related effects of the transgene, which is known to deplete the endogenous SA pool. In control conditions, SA levels of the top leaves of NahG plants were moderately lower than those of wild-type, while SA was considerably reduced in the bottom leaves. WL conditions triggered a rise in H₂O₂ concentrations in young leaves, which was exaggerated in NahG plants, pointing to a mitigating effect of SA against the stress-associated oxidative burden. The NahG transgenic leaves displayed lower protein levels than their wild-type counterparts, indicating a role of SA in protein retention. In non-stressed NahG plants, young (top) leaves showed an increased level of protein nitration. WL treatment triggered decreased protein contents in the leaves of both genotypes. This coincided with the high H₂O₂ content of old leaves exceeding that of young leaves in most cases. The expression of the senescence marker gene Cysteine protease 1 was upregulated in WL-stressed bottom leaves. According to this marker, senescence progressed faster in NahG leaves. Links between SA, protein nitration, and leaf senescence were discussed. Additionally, a stimulating effect of the NahG transgene was confirmed on adventitious roots (AR) formation, which may have helped root functions and thus probably contributed to maintaining the growth of the WL-stressed plants. Our results have implications for how endogenous SA levels influence plants in a WL stress situation. According to our findings, the depletion of SA may trigger protein loss and tyrosine nitration, but at the same time accelerates AR formation in WL-stressed tobacco. Full article

Intensifying drought stress under global climate change poses a significant threat to woody plants, highlighting the critical need to identify key genes conferring drought tolerance. Here, we characterized PsnSAUR6, a Small Auxin Upregulated RNA (SAUR) family gene from poplar (Populus simonii × P. nigra) that is responsive to drought and abscisic acid (ABA). Overexpression of PsnSAUR6 in transgenic tobacco conferred superior drought tolerance, evidenced by increased biomass, enhanced root elongation, improved stomatal regulation, and favorable physiological responses, including higher proline content and peroxidase (POD) activity but lower malondialdehyde (MDA). Transcriptome analysis revealed that under water deficit, PsnSAUR6 suppressed the ABA negative regulator PP2C37 while upregulating key antioxidant defense-related transcription factors (ERF020, NAC83, MYB2) and the potassium transporter HAK5. Collectively, these findings establish PsnSAUR6 as a positive regulator in ABA-mediated drought adaptation, presenting it as a promising genetic target for enhancing the climate resilience of woody plants. Full article

Background: Translational regulation constitutes a critical layer of gene expression control in plants, yet the contribution of endogenous 5′ untranslated regions (5′ UTRs) to translational efficiency remains incompletely defined. While viral and synthetic leader sequences have been widely used to enhance protein production, comparatively few native plant 5′ UTRs have been systematically characterised. The objective of this study was to identify and functionally evaluate endogenous plant 5′ UTR elements that promote translation through post-transcriptional mechanisms. Methods: A 79-nucleotide fragment (CYSTM α) derived from the 5′ UTR of Arabidopsis thaliana CYSTM1 (AT1G05340) was cloned upstream of reporter genes and assessed using dual-luciferase assays in transient expression systems (Nicotiana benthamiana and A. thaliana) and in stable transgenic Arabidopsis lines. Translational activity was further evaluated in monocot wheat germ extract and in Escherichia coli. Transcript abundance was quantified by qRT-PCR. Publicly available ribosome profiling and m⁶A datasets were analysed to assess translational efficiency and RNA modification status. Results: In N. benthamiana and A. thaliana, CYSTM α increases reporter protein production 3–7 fold relative to the control and 30–130% above the benchmark Tobacco Mosaic Virus (TMV) Ω leader, without altering mRNA abundance. The CYSTM α sequence also enhances luciferase translation in monocot wheat germ extract and elevates translation 5-fold in E. coli. CYSTM α contains three motifs that may promote translation, namely three CAA repeats that are associated with translation initiation, an AMAYAA motif that is associated with eIF3 binding, and two N6-adenosine DRACH sites that are associated with cap-independent translation. Additionally, ribosome profiling revealed high translational efficiency (TE = 3.25) of native CYSTM1. Conclusions: CYSTM α represents a compact endogenous 5′ UTR element that enhances translation across multiple experimental systems. These findings expand the repertoire of plant-derived translational enhancers and provide insight into sequence features associated with efficient mRNA translation in plants. Full article

Phosphorus deficiency in the environment induces phosphate (Pi) starvation responses of plants, in which the phosphate transporter is one of the most critical functional genes in this response mechanism. As a prevalent green manure crop in China, Vicia villosa plays a critical role in sustainable agricultural systems, and the expression of its phosphate transporter gene (VvPHT1) is modulated by soil phosphorus availability, highlighting its key adaptive function in nutrient acquisition and utilization under low-Pi conditions. Functional studies of this gene and its promoter contribute to exploring the molecular mechanisms of the tolerance of green manure crops to low phosphorus stress and to improving phosphorus-efficient V. villosa varieties. In this study, analysis of the VvPHT1 promoter sequence revealed a 1524 bp region containing multiple root-specific cis-regulatory elements, including five NODCON2GM, one NODCON1GM, six OSE2ROOTNODULE, one OSE1ROOTNODULE, and fifteen ROOTMOTIFTAPOX1 motifs. Histochemical GUS staining of transgenic Arabidopsis (Arabidopsis thaliana (L.) Heynh.) showed that the VvPHT1 promoter directed root-specific expression of the GUS reporter gene. A fusion expression vector pCAMBIA1300-VvPHT1--GFP was constructed and transformed into tobacco (Nicotiana tabacum L.) cells for subcellular localization analysis, indicating that the protein encoded by VvPHT1 was localized to the plasma membrane. To quantify its expression, VvPHT1 transcript levels in VvPHT1-overexpressing Arabidopsis (OEPHT1) lines were analyzed by quantitative real-time PCR (qRT-PCR) under different phosphorus supply conditions. The results demonstrated that under low-Pi conditions, the expression of VvPHT1 was significantly upregulated in the OEPHT1 lines compared to those of normal-Pi conditions. Furthermore, under low-Pi treatment, the OEPHT1 lines showed significantly increased fresh weight, primary root length, phosphorus content, and chlorophyll content compared to the wild-type Arabidopsis (WT), while no such differences were observed under normal-Pi conditions. In conclusion, the VvPHT1 promoter exhibits root-specific activity, and the VvPHT1 gene encodes a plasma-membrane-localized phosphate transporter that is strongly induced by phosphorus deficiency. Its overexpression enhances phosphorus uptake and plant growth under low-Pi conditions, suggesting that VvPHT1 likely functions as a high-affinity phosphate transporter involved in the adaptation to phosphorus starvation. Full article

Secondary cell wall (SCW) formation and lignin biosynthesis are critical biological processes that determine wood properties. Masson pine (Pinus massoniana Lamb) is a fast-growing conifer species with significant economic value for the pulp and paper industry. While R2R3-MYB transcription factors are known as master regulators of SCW biosynthesis, the specific R2R3-MYB members regulating lignin formation in Masson pine remain largely uncharacterized. In this study, we identified 317 R2R3-MYB genes in the Masson pine genome. Phylogenetic analysis revealed that PmMYB289, a member of the P20 subgroup, is highly homologous to the Arabidopsis SCW regulators AtMYB52 and AtMYB54. Expression profiling demonstrated that PmMYB289 is predominantly expressed in highly lignified old stems. Transcriptional activation assays confirmed that PmMYB289 lacks autoactivation activity. Subcellular localization analysis revealed that PmMYB289 was localized to the nucleus. Ectopic overexpression of PmMYB289 in tobacco (Nicotiana benthamiana) resulted in dwarfed plant growth, reduced stem diameter, and curled leaves. Molecular analysis of these transgenic lines showed a significant downregulation of most key SCW biosynthetic genes, with the exception of NbPAL1. These findings indicate that PmMYB289 acts as a crucial transcriptional repressor in SCW biosynthesis, providing valuable genetic resources for the molecular breeding of superior Masson pine varieties. Full article

Cunninghamia lanceolata (C. lanceolata), a pivotal economic timber species in southern China, faces increasing threats from global warming and heat stress. Due to limited knowledge regarding its stress response mechanisms, uncovering the molecular basis of heat tolerance is crucial for breeding resilient varieties. Therefore, the objective of this study was to elucidate the physiological and molecular mechanisms of C. lanceolata in response to heat stress. In this study, we performed a time-series transcriptomic analysis on leaves of C. lanceolata ‘6421’ seedlings exposed to heat stress (39 °C) for 0, 1, 4, 8, 12, and 16 h. A total of 1130 differentially expressed genes (DEGs) were identified, with functions primarily enriched in signal transduction, protein folding, and the MAPK and NF-kappa B signaling pathways. Weighted gene co-expression network analysis (WGCNA) revealed a complex regulatory network, identifying ClHsf8 as a central hub transcription factor. To validate its function, ClHsf8 was cloned and overexpressed in tobacco (Nicotiana benthamiana). Under heat stress conditions, transgenic plants exhibited enhanced thermotolerance compared to wild-type controls, characterized by significantly higher activities of antioxidant enzymes (SOD, POD, and CAT) and reduced accumulation of MDA and H₂O₂. Our findings elucidate the molecular regulatory mechanisms of C. lanceolata in response to high temperatures and demonstrate the functional role of ClHsf8 in conferring heat tolerance, providing a theoretical foundation for the genetic improvement of heat-resilient cultivars. Full article

Drought stress severely limits plant growth and productivity, yet the molecular basis of drought tolerance and post-drought recovery remains incompletely understood in many forage legumes. Medicago ruthenica is a perennial legume native to arid and cold regions and exhibits strong drought resilience. Results: We integrated key physiological traits related to stomatal regulation, photosynthesis, osmotic adjustment and antioxidant defense with RNA-seq across four stages (well-watered control, CK; drought for 9 days, D9; drought for 12 days, D12; and rewatering for 4 days, RW). Drought triggered stage-dependent physiological shifts, and transcriptome profiling identified >3000 drought- and rewatering-responsive genes enriched in primary metabolism, redox homeostasis and hormone signaling. WGCNA highlighted two drought-associated modules (MEcyan and MEcoral1) and prioritized three hub transcription factors for functional validation: 861 (AP2/ERF), 22 (WRKY) and 89 (bZIP). Overexpression of each gene in tobacco improved drought tolerance, as indicated by enhanced growth/root traits, increased osmolyte accumulation and antioxidant enzyme activities, and reduced membrane damage. Conclusions: Together, these results provide an integrated view of drought stress response and recovery in M. ruthenica and identify 861, 22 and 89 as candidate regulatory genes for engineering drought resilience in legumes. Full article