Search Results (75)

Squalene, a high-value triterpenoid precursor widely used in pharmaceuticals and vaccine adjuvants, is primarily sourced from shark liver oil—an unsustainable practice that has driven interest in developing plant-based production alternatives. The first committed reaction in triterpenoid biosynthesis is catalyzed by squalene synthase (SQS), yet no SQS gene has been characterized in Amaranthus tricolor, a species recognized for its high squalene content. Here, we cloned and functionally characterized AtrSQS, a novel squalene synthase gene isolated from A. tricolor for the first time. Sequence analysis revealed that AtrSQS contains conserved domains and six characteristic motifs shared among plant SQSs, with high homology to orthologs from dicotyledonous species. To investigate its functional role in squalene biosynthesis, AtrSQS was overexpressed in Nicotiana tabacum under the CaMV 35S promoter. Transgenic lines exhibited significantly increased AtrSQS expression and accumulated squalene up to 6.81 μg/g dry weight, a 4.76-fold increase over wild-type plants. Additionally, the content of downstream product 2,3-oxidosqualene was also significantly elevated in the transgenic lines. Integrated transcriptomic and metabolomic analyses revealed that AtrSQS overexpression upregulated key mevalonate pathway genes (AACT, HMGS, MVD) and FPPS. Meanwhile, it suppressed competitive carotenoid biosynthesis and the production of an SQS-specific inhibitor, indicating a successful redirection of metabolic flux toward squalene production. These findings demonstrate that AtrSQS is crucial for squalene biosynthesis and provide both a valuable genetic resource and mechanistic insights for engineering plant-based squalene production systems. 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

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

Objectives: Flavonoids are a class of widely distributed secondary metabolites in plants. Ginkgo biloba leaves are rich in flavonoids and thus are utilized for extracting medicinal components to treat and prevent cardiovascular and cerebrovascular diseases. Flavonol synthase (FLS) serves as a key enzyme in the flavonol metabolic pathway. Numerous studies have identified and characterized FLS family genes across various plant species, all of which play crucial roles in regulating the flavonoid biosynthetic pathway. Methods: We measured the flavonoid content in Ginkgo biloba leaves across different months, performed transcriptomic analysis on leaves from months showing an increasing trend, and screened out the GbFLS1045 gene involved in the synthesis of the FLS enzyme. Molecular biology techniques were then employed to explore the function of the GbFLS1045 gene. Results: From June to August, the flavonoid content in Ginkgo biloba leaves exhibited an upward trend, and we found that GbFLS1045 is localized in the cytoplasm, cell membrane, and nucleus through transient transformation in Nicotiana tabacum. Overexpression(OE) of GbFLS1045 in Arabidopsis thaliana resulted in significantly higher levels of total flavonol glycosides, kaempferol, quercetin, and isorhamnetin in OE transgenic plants compared to WT controls. Furthermore, in OE lines of Ginkgo biloba callus, the isorhamnetin content was consistently elevated relative to both WT and Anti lines. Conclusions: GbFLS1045 positively regulates flavonoid synthesis in Ginkgo biloba. Full article

Acyl-CoA-binding proteins (ACBPs) possess a conserved acyl-CoA-binding (ACB) domain that facilitates binding to acyl-CoA esters. In addition to their typical role in lipid metabolism, plant ACBPs have been shown to participate in various physiological processes, such as membrane biogenesis, stress response pathways and plant immunity mechanisms. Here, we identified five PutACBP members in alkaligrass (Puccinellia tenuiflora), which were divided into four distinct classes based on a phylogenetic tree constructed from 86 ACBP genes from 12 plant species. Promoter analysis identified numerous cis-acting elements linked to abiotic stresses (e.g., light, drought, heat, and cold) and hormone responses. Expression profile analyses revealed that PutACBPs exhibit broad expression patterns across many organs and respond to salinity-alkali, cold, H₂O₂, and CdCl₂ stresses. Transient expression of five PutACBP-GFPs in tobacco (Nicotiana tabacum) revealed PutACBP1 and PutACBP2 localized to the plasma membrane, cytoplasm, and cell nucleus, while PutACBP3, PutACBP4, and PutACBP5 localized around the plasma membrane and cytoplasm. Furthermore, heterologous constitutive expression of PutACBP3 in Arabidopsis (Arabidopsis thaliana) enhanced the resistance of transgenic plants to salinity stress, possibly through alterations in the levels of lipid metabolism-related and stress-responsive genes. The ACBP gene family is highly conserved across different plant species. This study provides the first comprehensive genomic and functional characterization of the PutACBP family in alkaligrass, elucidating its evolutionary conservation, phylogenetic classification, and stress-response roles. Notably, overexpression of PutACBP3 in Arabidopsis significantly enhanced salt tolerance, suggesting its critical function in salt-stress adaptation in alkaligrass. Full article

Drought stress is a major limiting factor during the process of plant growth and development, especially in arid and semi-arid regions. MYB transcription factors play vital roles in the regulation of many developmental processes under various stresses. The aim of this study was to determine whether PtrMYB119 enhanced dehydration tolerance in Nicotiana tabacum. PtrMYB119, with a weak transactivation activity, was distributed throughout the cell with no apparent specificity. The transgenic tobacco overexpressing PtrMYB119 might regulate dehydration tolerance through increased ABA content and antioxidant enzyme activities, decreased MDA levels, and up-regulation of antioxidant genes, polyamine biosynthesis genes, and drought-responsive genes. Overall, our results could contribute to the elucidation of drought tolerance underlying PtrMYB119 action in tobacco and indicated that PtrMYB119 could be exploited for engineering drought-enduring plants in the future. Full article

Male sterility is an important trait in heterosis utilization and marigold (Tagetes erecta L.) breeding. Currently, most male-sterile lines used in production are derived from natural mutations. ABORTED MICROSPORES (AMS) is an important gene that regulates tapetum and microspore development. Therefore, the effect of AMS on fertility was studied. TeAMS was located in the nucleus and exhibited self-activation activity. TeAMS was highly expressed in the flower buds of T. erecta. The expression of this gene in fertile plants was higher than that in sterile plants, and the expression level gradually increased with the development of flower buds. The expression level of TeAMS was highest in the flower buds with a diameter of 1.2 cm at the floret differentiation stage, while the expression level was extremely low in the flower buds with a diameter of 1.6 cm. The expression trend of TeAMS in sterile plants was opposite to that in fertile plants. At the inflorescence primordium differentiation stage, flower buds with a diameter of 0.2 cm had the highest expression level, and the stem tip had the lowest expression level. In tobacco (Nicotiana tabacum L.), overexpression of the TeAMS gene resulted in shortened floral tubes, increased thousand-seed weight, a reduced flowering period, and decreased flower numbers. The pollen viability of transgenic tobacco was significantly lower than that of the wild type, and the pollen grains were smaller and showed irregular shapes. The pollen wall was dry and shrunk. Some pollen germinal furrows were distorted, and a few were almost invisible. Silencing TeAMS resulted in a longer flowering period in tobacco, reduced thousand-seed weight, and high pollen viability. Pollen morphology in silenced lines showed no significant differences compared to the wild-type and empty vector controls. Only a few pollen grains were smaller, shriveled, and shrunken. Therefore, the TeAMS gene plays an important role in regulating the fertility of marigolds. This study provides a theoretical foundation for breeding marigold male-sterile lines. Full article

Dryopteris fragrans (L.) Schott synthesizes volatile sesquiterpenes through the mevalonate pathway (MVA), in which 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) serves as the key rate-limiting enzyme. Although HMGR plays a crucial role in terpenoid biosynthesis, its functional characteristics in D. fragrans and its involvement in stress responses remain unclear. This study identified three HMGR genes (DfHMGR1/2/3) from the transcriptome data of D. fragrans. Bioinformatics analysis revealed that the encoded proteins are localized to the endoplasmic reticulum and share high sequence similarity with fern homologs. Under abiotic stress conditions, DfHMGRs exhibited differential expression patterns, with marked upregulation under salt and drought stress. To validate the functions of these genes, we generated transgenic Nicotiana tabacum L. plants overexpressing DfHMGRs. Compared with wild-type controls, the transgenic lines showed enhanced tolerance to drought and heat stress. Promoter analysis identified functional regulatory regions controlling DfHMGR expression, and co-expression network analysis predicted 21 potential transcriptional regulators. This study validates the function of D. fragrans HMGRs in a heterologous system and provides candidate genes for improving stress resistance in plants. Full article

Phytochelatins (PCs) are well-characterized for their role in detoxifying non-essential metals like cadmium (Cd), but their role in zinc (Zn) homeostasis remains underexplored. In this study, we investigated the role of the Nicotiana tabacum phytochelatin synthase 1 (NtPCS1) in counteracting Zn toxicity in plants. qRT-PCR data showed that the transcript level of the NtPCS1 gene was upregulated by ZnSO₄, leading to increased PC production in the wild-type tobacco plants. Functional complementation assays in Arabidopsis thaliana revealed that overexpression of NtPCS1 rescued the Zn hypersensitivity of the Atpcs1 mutant, with the N-terminal region being indispensable for Zn tolerance. In addition, transgenic tobacco plants overexpressing NtPCS1 (PCS1 lines) exhibited superior root elongation under ZnSO₄ stress compared to the wild-type plants, particularly when supplemented with glutathione (GSH). The observed phenotypic advantage is attributed to NtPCS1-mediated overproduction of PCs, which facilitated Zn chelation and enabled cellular detoxification. These findings highlight the important role of NtPCS1 in Zn tolerance via GSH-linked PCs synthesis, offering insights into PCS-mediated Zn detoxification and a genetic strategy for developing Zn-resistant plants. Full article

Plant aquaporin proteins (AQPs) are categorized into seven distinct families, among which, plasma membrane intrinsic proteins (PIPs) play pivotal roles in plant growth and physiological processes. In this study, we identified 11 CpPIP genes in wintersweet (Chimonanthus praecox (L.) Link) based on bioinformatic characterization of gene structural organization, chromosomal localization, and phylogenetic relationships. Subsequent phylogenetic reconstruction resolved two evolutionarily distinct CpPIP subclasses. We focused on the isolation and characterization of CpPIP1;1, which showed the highest expression in floral organs. During flowering, a significant increase was observed in the expression of the CpPIP1;1 gene in response to a gradual reduction in environmental temperature. Moreover, the overexpression of CpPIP1;1 in Arabidopsis thaliana resulted in early flowering and an enhanced tolerance to salt, drought, and cold stress. We subsequently transcriptionally fused the CpPIP1;1 promoter containing MYC and MYB low-temperature response elements to the β-glucuronidase (GUS) reporter gene and introduced this construct into Nicotiana tabacum. GUS activity assays of the transgenic plants revealed that the CpPIP1;1 promoter was effectively expressed in flowers. Furthermore, the promoter transcriptional activity was enhanced in response to salt, drought, cold, gibberellic acid, and methyl jasmonate treatments. Collectively, our findings in this study revealed that CpPIP1;1 plays a key role in the regulation of flowering and stress tolerance in wintersweet plants. Full article

Expansins are cell wall-modifying proteins that play a pivotal role in plant growth, development, and stress adaptation to abiotic stress. This manuscript explores the functions of expansins in salt and drought stress responses across multiple plant species, highlighting their involvement in cell wall loosening, transcriptional regulation, ion and osmotic homeostasis, and phytohormone signalling. Genome-wide identification and expression analyses revealed differential regulation of expansin genes under abiotic stress conditions. In Nicotiana tabacum, overexpression of NtEXPA4 and NtEXPA11 promoted root elongation and ion homeostasis, improving salt and drought tolerance. Similarly, Brassica rapa BrEXLB1 was found to modulate root architecture and phytohormone-mediated stress responses. In Oryza sativa, OsEXPA7 was linked to cation exchange and auxin signalling under salt stress conditions. Conversely, in Populus trichocarpa, PtEXPA6 exhibited a negative regulatory role in salt stress tolerance, highlighting species-specific differences in expansin function. Expansins also contribute to reactive oxygen species (ROS) homeostasis, as observed in transgenic plants with increased activities of SOD, POD, APX, and CAT, which reduced oxidative damage under stress. Additionally, enhanced accumulation of soluble sugars and proline in expansin-overexpressing plants suggests their involvement in osmotic adjustment mechanisms. The interplay between expansins and ABA, auxins, and ethylene further underscores their role in integrating mechanical and hormonal stress responses. Despite substantial progress, limitations remain in understanding the broader regulatory networks influenced by expansins. Future research should focus on elucidating their downstream molecular targets, transcriptional interactions, and functional diversity across different plant species. Expansins represent promising candidates for improving crop resilience to environmental stress, making them valuable targets for future breeding and biotechnological approaches. Full article

Osmanthus fragrans is a highly valued ornamental tree species in China, but its short flowering period limits its ornamental appeal. Investigating the mechanisms of flower senescence in O. fragrans is therefore of significant importance. Ethylene, a key endogenous hormone, plays a central role in flower senescence, and the AP2/ERF gene family, which includes ethylene response factors, is known to regulate this process in various plants. Transcriptome sequencing and expression analysis identified OfERF17 as a critical gene influencing petal senescence in O. fragrans. Bioinformatics analysis revealed that OfERF17 lacks transmembrane transport structures but contains multiple phosphorylation sites and shares a close phylogenetic relationship with the Olea europaea var. Sylvestris. Subcellular targeting and yeast-based auto-activation tests revealed that OfERF17 resides in the nucleus and possesses a transcriptional self-activation capability. Transient expression studies conducted in O. fragrans petals indicated a decrease in the expressions of two genes associated with senescence, namely, OfSAG21 and OfACO3, when compared to the control group. Additionally, the levels of hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) were markedly reduced. Transgenic Nicotiana tabacum blooms one day more than the wild type, and NtSAG12 and NtACO1 expressions were lower than wild type. These results suggest that OfERF17 functions to delay petal senescence in O. fragrans. This study enhances our knowledge of the molecular mechanisms underlying O. fragrans petal senescence and provides insights into strategies for prolonging its flowering period. Full article

Background/Objectives: Plants release extracellularly lipid bilayer-enclosed vesicles of nanometric size that can be retrieved in their fluids. Plant-derived extracellular vesicles (PDEVs) have mostly been involved in modulating host–pathogen interaction, making them a tool for cross-kingdom communication with a key role in plant immunity. In addition, PDEVs have demonstrated promising therapeutic features, not only in terms of intrinsic nutraceutical properties but also of active molecules’ delivery. Transgenic plants have been developed for a variety of purposes, i.e., to improve their functional properties like crops, but also to produce therapeutic molecules. However, it is unclear whether transgenes can end up in PDEVs, thus making them a vehicle for their cross-kingdom diffusion into the environment. Methods: Here, we investigated the association of transgenic DNA and RNA with PDEVs secreted by tobacco (Nicotiana tabacum) engineered to express the neomycine phosphotransferase II (Npt-II) gene. PDEVs were isolated from leaf apoplastic fluid by ultracentrifugation and characterized for their morphology and size. The association of DNA and RNA was assessed by qRT-PCR and their immunomodulatory properties by assaying PDEVs-induced IL1β and IL10 on THP1 monocytes. Results: Npt-II RNA, but not DNA, could be amplified from PDEVs, whereas no differences were observed between wt and transgenic tobacco PDEVs in terms of immunomodulatory properties. Conclusions: Although a different behaviour by other types of RNAs or DNAs could still be possible, our findings indicate that in this model, PDEVs are not associated with transgenic DNA, but they can protect RNA, including transgenic RNA, from degradation, contributing to their cross-kingdom spreading. Full article

Flower color is one of the most ornamental values of Meconopsis wilsonii, but very limited studies have been reported on its flower color formation. The UDP-glycosyltransferase (UGT) gene family plays a crucial role in plant flower color formation. In this study, the full-length transcriptome data of M. wilsonii was used to identify MwUGTs, focusing on protein physicochemical properties’ subcellular localization, and phylogenetic relationships. In addition, sequence analysis, expression pattern analysis, subcellular localization, and functional validation of MwUGT2 were also performed. A total of 26 MwUGTs were identified in full-length transcriptome and clustered into eight subgroups. Phylogenetic analysis and KEGG database annotation showed that MwUGT2 is associated with anthocyanin synthesis and accumulation. Subsequently, based on the expression of MwUGT2 during flower development and in different tissues, it was preliminarily determined that MwUGT2 plays a role in the flower bud stage. Subcellular localization assays suggested that MwUGT2 is present in the nucleus and cytoplasm. Overexpression in Nicotiana tabacum showed that MwUGT2 significantly increased the content of Cyanidin-3-O-glucoside and resulted in dark pink flowers in transgenic plants. In summary, our findings suggest that MwUGT2 plays a crucial role in the biosynthesis of anthocyanin and will also contribute to understanding the mechanisms of flower color formation in M. wilsonii. Full article

Tea plant (Camellia sinensis) is an important horticultural crop. The quality and productivity of tea plants is always threatened by various adverse environmental factors. Numerous studies have shown that intercropping tea plants with other plants can greatly improve the quality of their products. The intercropping system of Chinese chestnut (Castanea mollissima) and tea plants is an agricultural planting model in which the two species are grown on the same piece of land following a specific spacing and cultivation method. Based on a comparative transcriptome analysis between Chinese chestnut tea intercropped plantations and a pure tea plantation, it was found that the expression levels of the WRKY genes were significantly upregulated under the intercropping pattern. In this study, we cloned a candidate gene, CsWRKY48, and verified its functions in tobacco (Nicotiana tabacum) via heterologous transformation. The contents of protective enzyme activities and osmoregulatory substances were significantly increased, and the trichomes length and density were improved in the transgenic tobacco lines. This phenotype offered an enhanced resistance to both low temperatures and aphids for transgenic lines overexpressing CsWRKY48. Further analysis indicated that the CsWRKY48 transcription factor might interact with other regulators, such as CBF, ERF, MYC, and MYB, to enhance the resistance of tea plants to biotic and abiotic stresses. These findings not only confirm the elevated resistance of tea plants under intercropping, but also indicate a potential regulatory network mediated by the WRKY transcription factor. Full article