Search Results (262)

Plasma membrane intrinsic proteins (PIPs), a subfamily of aquaporins (AQPs), play critical roles in various physiological processes in plants, including the transport of water and CO₂, regulation of stomatal movement, absorption of neutral molecules and nutrients, and H₂O₂ signaling. Nevertheless, the functions of PIP aquaporins in adventitious root formation in trees are still poorly understood. PtrPIP2:4 is specifically expressed in roots, and PtrPIP2:4 fused with GFP localizes to the plasma membrane. Overexpression of PtrPIP2:4 significantly accelerated adventitious root induction in poplar. Stem cuttings from overexpression lines exhibited more rapid rooting compared to wild-type (WT) plants, although the total number of adventitious roots did not differ significantly. Additionally, the number of lateral roots was markedly increased in PtrPIP2:4 overexpression lines. Comparative transcriptome analysis identified 4204 differentially expressed genes (DEGs) between WT and PtrPIP2:4 overexpression plants. Transcriptomic analysis revealed that genes associated with auxin-related and flavonoid biosynthesis were significantly enriched. RT-qPCR results showed that the transcription levels of nine auxin-related genes (i.e., PtrARF, PtrIAA, PtrGH3 and PtrPIN) were significantly upregulated, while the transcription levels of five flavonoid synthesis genes (i.e., PtrDFR, PtrANS, PtrANR and PtrLAR) were also significantly upregulated. Previous studies have implicated these genes in adventitious root formation. Collectively, these findings reveal that PtrPIP2:4 accelerates adventitious root emergence, promotes adventitious root elongation, and increases lateral root number while the total number of adventitious roots exhibited no significant difference in poplar, suggesting its potential utility in improving tree propagation and breeding strategies. Full article

American ginseng (Panax quinquefolius L.) is an important medicinal crop, but its improvement in China is limited by variety degeneration and a shortage of elite cultivars. In this study, phenotypic traits and simple sequence repeat (SSR) markers were integrated to evaluate the genetic diversity of 51 selected accessions from major Chinese production regions. Phenotypic analysis showed that five of the 18 quantitative traits had phenotypic coefficients of variation exceeding 40%, mainly involving root traits such as fresh root weight and lateral root number. Broad-sense heritability for these root traits ranged from 61.70% to 74.80%, indicating substantial genetic contribution under standardized conditions. Principal component analysis identified five candidate elite accessions: CY3 and KD1 for tall stature and high yield, DH1 and LH2 for high ginsenoside content, and AT1 for well-developed lateral roots. A 12-accession representative subset was further proposed for conservation and pre-breeding. SSR-based clustering showed weak geographic differentiation, and Mantel analysis revealed no significant correlation between phenotypic and SSR-based genetic distances. These materials, together with the proposed accession-level conservation strategy, provide useful resources for germplasm preservation, parental selection, QTL mapping, and marker-assisted breeding. Full article

Peach (Prunus persica L.) trees exhibit low propagation efficiency from cuttings, primarily due to the limited ability of their cuttings to develop adventitious roots (ARs). ARs originate from a single or a few cells and occur randomly and in varying numbers at the base of the cuttings. This poses a challenge for precise research on their regulatory mechanisms. Adventitious lateral roots (adLRs) are one kind of AR, which are induced from injured primary roots. In this study, we developed a method to induce adLRs by removing part of the primary root of young peach seedlings. The adLRs induced by this method are characterized by no obvious callus formation, a relatively stable number (2–4 roots), a fixed occurrence position (at the incision site), and a rooting rate of 100%. Using this system, we conducted transcriptome sequencing analysis during the early stage of adLR induction (0–24 h). The results showed that after the primary root was removed, the jasmonic acid (JA), wound, ethylene (ET), auxin, and salicylic acid (SA) signaling pathways were rapidly activated; subsequently, pathways related to root formation and development were significantly enriched. By screening early rapid-response genes, we successfully identified two key genes, PpF-box and PpERF13, that are involved in AR formation in peach. This study not only provides a reliable and efficient research system for analyzing the molecular regulatory mechanism of AR formation in peach, but also lays an important foundation for future in-depth studies using precise technologies such as single-cell sequencing and microscopic sampling. Full article

The toxicity of copper (Cu) severely affects the growth and physiological metabolism of plants. 2-(3,4-Dichlorophenoxy) triethylamine (DCPTA) is a plant growth regulator known to enhance plant tolerance to various abiotic stresses; however, its specific role in mitigating Cu toxicity via cell wall modulation and nitrogen metabolism remains unclear. “Zhongnong 26” (Cucumis sativus L.) seedlings were subjected to a randomized block design with four treatments: control (CK), 0.25 mg/L DCPTA, 50 μM Cu, and 50 μM Cu + 0.25 mg/L DCPTA, with three biological replicates per treatment. The results indicated that DCPTA application significantly alleviated Cu-induced growth inhibition. Specifically, DCPTA improved root system architecture by markedly increasing total root length (68.8%), surface area (68.7%), and the number and length of secondary lateral roots (69.6%, 173.2%). Furthermore, DCPTA enhanced the biosynthesis of cell wall polysaccharides—including pectin (24.3%), hemicellulose 1 (22.4%), hemicellulose 2 (23.7%) and cellulose (33.1%) in roots. Fourier Transform Infrared (FTIR) spectroscopy analysis revealed that DCPTA modified functional groups (e.g., –OH, –COOH) within the cell wall, enhancing their metal-chelating capacity. Consequently, DCPTA promoted the immobilization of Cu in the root cell wall fractions (particularly pectin and HC2) and shifted Cu into less toxic, pectate- and protein-bound forms, thereby reducing its translocation to leaves. Additionally, DCPTA restored the activities of key nitrogen metabolism enzymes in leaves and roots. Compared with Cu treatment alone, nitrate reductase (NR) activity increased by 77.7% and 90.6%, while glutamine synthetase (GS) activity remained stable, and glutamate synthase (GOGAT) activity increased by 10.3% and 71.3% in leaves and roots, respectively. In conclusion, DCPTA enhances copper sequestration in roots by coordinating the regulation of root structure and cell wall strengthening (with an increase in pectin and hemicellulose content). This is crucial for protecting the nitrogen metabolism within the cells (including the enzymes that drive the nitrate–ammonium reduction pathway) to maintain metabolic balance under Cu stress. Full article

Smart insoles equipped with pressure sensor matrices are increasingly used for gait analysis, yet high-density arrays compromise battery life and data throughput. This study aims to identify the optimal sparse sensor layout required to accurately estimate the Center of Pressure (CoP) by analyzing the trade-off between sensor number, spatial placement, and reconstruction error. Plantar pressure data were collected from twelve healthy participants walking at a self-selected speed using 16-sensor connected insoles. A combinatorial algorithm evaluated all $2^{16}-1$ possible sensor combinations to minimize the Root Mean Square Error (RMSE) in the antero-posterior, medio-lateral, and global Euclidean directions. Results reveal a non-linear convergence of accuracy that depends on the spatial axis. For longitudinal and global progression, a clear inflection point achieving sub-centimetric accuracy (RMSE < 5 mm) is reached at seven sensors. In contrast, medio-lateral tracking shows its largest discrete error reduction at five sensors, followed by gradual improvements at higher densities. Anatomical frequency analysis highlights distinct spatial requirements: the posterior heel is consistently selected for medio-lateral accuracy, while the lateral arch and metatarsal regions are critical for longitudinal progression. These findings suggest that while a minimum of seven strategically placed sensors enables robust CoP tracking across all spatial axes, optimal hardware design should remain task-specific. This work provides a data-driven framework for the development of energy-efficient wearable gait monitoring systems. Full article

Some actinobacterial species have been reported to improve plant growth due to their roles as biostimulants and biological control agents. In this study, the effect of actinobacterial isolate 27, obtained from the rhizospheric soil of melon plants and identified as Streptomyces calvus, was evaluated on the growth of Arabidopsis thaliana and tomato plants. In Arabidopsis, in vitro assays showed that after seven days of interaction, isolate 27 increased fresh weight by 1.4-, 1.5-, and 2.3-fold and lateral root number by 1.7-, 1.3-, and 2.5-fold under physical contact and split-plate systems (MS and ISP2 media), respectively, compared with non-inoculated plants. An increased β-glucuronidase (GUS, encoded by the uidA gene) signal was observed in primary and lateral roots of the Arabidopsis DR5::uidA reporter line during both interaction types, suggesting the activation of auxin-responsive pathways. In addition, isolate 27 rescued the rhd6 (root hair defective 6) mutant phenotype, restoring root hair formation. Gas chromatography-mass spectrometry (GC-MS) analysis revealed that isolate 27 emitted volatile organic compounds (VOCs), including an alcohol and several sesquiterpenes, and that this profile changed during interaction with Arabidopsis plantlets. In soil-based pot assays, inoculation with isolate 27 significantly enhanced the development of Arabidopsis plants after 23 days, both when applied alone and in co-inoculation with Trichoderma atroviride. Furthermore, isolate 27 stimulated tomato plant growth, leading to significant increases in fresh and dry biomass, as well as shoot and root lengths after 28 days. Overall, these results demonstrate that S. calvus isolate 27 promotes plant growth and development through the production of bioactive compounds that modulate plant growth pathways, including hormonal responses, highlighting its potential as a bioinoculant for sustainable and productive agricultural systems. Full article

ERF/AP2 is a family of transcription factors that plays a broad role in plant growth and development and in responses to various environmental stresses. In our previous studies, we found that the transcription factor LoERF4 indirectly induces the breaking of dormancy in lily bulbs by regulating its downstream gene, LoXTH23. To further investigate the function of LoERF4, we overexpressed it in Arabidopsis thaliana. Paraffin section analysis revealed that root cells in OE-LoERF4 transgenic Arabidopsis thaliana lines exhibited significantly longer average cell lengths compared to the wild type. In the overexpression lines, the expression of multiple modified genes, including AtXTHs and AtEXPAs was significantly upregulated, and these lines exhibited earlier lateral root emergence and a significant increase in primary root length. Under 100 mM sodium chloride treatment, the overexpression lines exhibited significantly higher numbers of lateral roots, true leaves, and primary root length compared with the wild type (WT). In the OE-LoERF4 line, antioxidant enzyme (SOD, POD, CAT) activity was enhanced, oxidative damage was reduced (decreased MDA content), and root survival rate was improved (as reflected by TTC reduction). This confirms that LoERF4 may promote root development in the overexpression line by positively regulating downstream AtXTHs and AtEXPAs, while simultaneously enhancing the salt tolerance of the overexpression line. Full article

Cassava (Manihot esculenta Crantz) is a nitrogen-efficient crop that can achieve high biomass production on poor soils. However, the mechanisms underlying the response of cassava to nitrogen-deficiency signals and the regulation of nitrogen use efficiency remain unclear. Here, we found that MeCEPD (MeGRXC1) was specifically induced by CEP6 peptides and low nitrate, and showed higher expression in leaves and stems. Overexpression of MeCEPD enhanced cassava’s tolerance to nitrate deficiency by upregulating the expression of MeNRT2.1, MeNRT2.4, and MeRBCS1A, which was manifested as increased root biomass, greater lateral root number, and darker leaf coloration. In contrast, the MeCEPD-edited lines exhibited a statistically significant reduction in root length, plant height, and biomass compared to the wild-type. Additionally, nitrate deficiency accelerated leaf senescence. Furthermore, yeast two-hybrid (Y2H) assay revealed that MeCEPD interacts with the photosynthesis-related MeRBCS1A and lateral root development-related MeLHW, which may regulate nitrogen use efficiency. Unlike its Arabidopsis thaliana homologs AtCEPD1/2 and AtCEPDL2, which interact with AtTGA1/4, MeCEPD does not interact with MeTGA1 yet still upregulates MeNRT2.1 expression. These findings contribute to our understanding of the complex regulatory mechanisms underlying cassava’s adaptation to low-nitrogen conditions and could provide new information for genetic improvement in nitrogen use efficiency in cassava. Full article

The Lateral Organ Boundaries Domain (LBD) gene family encodes plant-specific transcription factors that play pivotal roles in growth, development, and stress responses. However, a comprehensive genome-wide analysis of the LBD family in watermelon (Citrullus lanatus) has not been conducted until now. In this study, we identified 39 ClLBD genes using the latest watermelon reference genome and systematically analyzed the function of ClLBD2 in root development. These ClLBDs are unevenly distributed across 10 chromosomes except Chr4. Evolutionary analysis grouped the gene family members into six subgroups: Class I (a–e) and Class II. Physicochemical properties and gene structure analysis showed that the ClLBD protein members are tightly conserved. In the promoter regions of ClLBD genes, we identified abundant cis-acting regulatory elements related to abiotic stress and hormone responses. Through RNA-seq analysis from a cucurbit database, we found that several ClLBD genes showed high relative expression in roots, with ClLBD2 being the most highly expressed. Since its subfamily includes AtLBD25, a known root development-related gene, we hypothesized that ClLBD2 might be involved in root development. To validate this, ClLBD2-edited roots were generated using the CRISPR-Cas9 system and Agrobacterium rhizogenes-mediated transformation. Compared to the wild type, the ClLBD2 edited roots exhibited significant reduction in taproot length and lateral root numbers, indicating that ClLBD2 may regulate root development. This study provides the first comprehensive analysis of the LBD gene family in watermelon, offering valuable insights for evolutionary and further functional studies of ClLBD genes. Full article

Plants are frequently exposed to various abiotic stresses during their growth and development. S. portulacastrum possesses inherent tolerance to salinity and heavy metals, yet the underlying molecular mechanisms remain poorly understood. In this study, we performed a comprehensive analysis of S. portulacastrum by integrating full-length transcriptome sequencing and RNA sequencing (RNA-seq) under salt stress conditions. Transcriptome analysis identified 2839 and 1813 DEGs in leaves and 7328 and 754 DEGs in roots at 7 and 14 ds after NaCl treatment, respectively. Pathway enrichment analysis indicated that these DEGs were significantly enriched in pathways associated with Photosynthesis, plant hormone signal transduction, Linoleic acid metabolism, chlorophyll metabolism, and amino acid metabolism. Expression profiling showed that JAZ subfamily genes were significantly upregulated in both leaves and roots under salt and Cd stress. We cloned SpJAZ1, SpJAZ5, and SpJAZ7, and generated their overexpression lines in Arabidopsis. Physiological assays demonstrated that overexpression of SpJAZ1, SpJAZ5, and SpJAZ7 reduced hydrogen peroxide content by 29.07%, 20.62%, and 19.79%, respectively, and lowered the reduction in chlorophyll content (0.12, 0.15, and 0.17 μg/mL vs. 0.22 μg/mL). Meanwhile, proline content was increased in these lines (2.34, 2.08, and 2.05 μg/mL vs. 1.53 μg/mL), alongside enhancements in root length, lateral root number, and water content under salt stress. Importantly, these overexpression lines displayed a similar functional trend under Cd stress. Collectively, our results reveal potential crosstalk between the JA signaling pathway and stress mitigation pathways in S. portulacastrum in response to salt and Cd stresses. Full article

Soil salinization severely restricts the sustainable development of the pear industry. Pyrus betulifolia, a vital native salt-tolerant rootstock in China, holds great significance for investigating stress resistance mechanisms. Plant-specific DNA-binding One Zinc Finger (Dof) transcription factors act as pivotal regulators in stress adaptation. However, their functions in P. betulifolia remain largely unexplored. In this study, we identified 43 PbeDof members within the P. betulifolia genome and classified them into eight subfamilies via phylogenetic analysis. Gene structure and conserved motif analyses revealed that PbeDof members within the same subfamily share similar exon-intron organizations and protein architecture, suggesting evolutionary conservation. Promoter analysis indicated that PbeDof genes are rich in cis-acting elements related to light, phytohormones (especially ABA and MeJA), and stress responses, implying their potential roles in diverse biological processes. Chromosomal localization and collinearity analyses revealed that segmental duplication was the primary driver of this family’s expansion. Combined transcriptomic profiling and qRT-PCR assays demonstrated that PbeDof9.1 is predominantly expressed in roots and is strongly induced by salt stress. Subcellular localization confirmed that PbeDof9.1 targets the nucleus. Functional characterization indicated that heterologous overexpression of PbeDof9.1 in Arabidopsis thaliana significantly enhances salt tolerance at germination and seedling stages. Notably, under 175 mM NaCl stress, the transgenic lines exhibited a superior root system architecture, with primary root length and lateral root numbers being approximately 1.5-fold higher than those of the wild type. Furthermore, homologous overexpression in pear calli confirmed that PbeDof9.1 mitigates oxidative damage by boosting the activities of peroxidase (POD) and catalase (CAT) to scavenge reactive oxygen species (ROS), thereby reducing malondialdehyde (MDA) accumulation. Collectively, this study characterizes the PbeDof family and establishes PbeDof9.1 as a key candidate gene for the genetic improvement of salt tolerance in pear rootstocks. Full article

Grasslands are ecosystems of global importance; in Peru, they represent more than half of the country’s territory. However, few studies have been conducted on high Andean grasslands. The objective was to study morphological, productive, resource allocation, and nutritional characteristics in five populations of Festuca dolichophylla grown under similar conditions. Populations that originated from Huancavelica Community and University, Junín, Pasco, and Puno were grown in Huancavelica Community in a randomized block design. After twelve months, a uniformization cut was performed, and five months later they were evaluated. Morphological characteristics, productivity, and resource allocation were analyzed with ANCOVA, the nutritional characteristics were analyzed with one-way ANOVA (considering population as a factor). Significant differences (p < 0.05) were found for morphological characteristics such as height, number and length of stems, and number of inflorescences. The resource allocation was 13.8% root, 18.4% crown, 29.2% culms + sheaths, 34.8% blades, and 3.8% inflorescence, with no differences between populations (p > 0.05). The Puno population stood out for its greater biomass, linked to more stems and inflorescences. Nutritional characteristics varied among populations in terms of crude fiber, neutral detergent fiber, acid detergent fiber, and in vitro dry matter digestibility. These findings are useful for selecting populations in revegetation or genetic breeding programs. Full article

An accurate in situ stress field is a prerequisite for evaluating the stability of surrounding rock in underground caverns of a pumped-storage power station (PSPS) and ensuring the long-term safe operation of underground powerhouses. However, in situ stress measurements in the field are typically characterized by a limited number of measurement points, strong data randomness, and high testing costs. Meanwhile, conventional regression inversion methods often yield stress fields with insufficient accuracy or unstable spatial distributions. To address these issues, this paper proposes an in situ stress field inversion method based on the particle swarm optimization–support vector regression (PSO-SVR) algorithm. Stress boundary conditions are formulated in terms of lateral stress coefficients combined with shear stresses, and PSO is employed to optimize the hyperparameters of the SVR model. The stress boundary conditions predicted by the PSO-SVR algorithm are then imposed on a numerical model to compute the stresses at the measurement points, and the optimal boundary conditions are identified by minimizing the root mean square error (RMSE) between the inverted and measured in situ stresses. On this basis, the stress components at the measurement points and the in situ stress field in the study area are obtained. The results demonstrate that the inverted in situ stresses agree well with the field measurements, exhibiting good consistency and spatial regularity. Specifically, compared with the traditional multiple linear regression (MLR) method, the PSO-SVR algorithm reduces the RMSE and mean absolute error (MAE) of the in situ stress measurement data by 48.21% and 47.01%, respectively, and produces inversion results with higher accuracy, more stable spatial patterns, and markedly fewer anomalous zones. Consequently, the PSO-SVR algorithm is well suited for in situ stress inversion in PSPSs and provides a reliable stress-field basis for subsequent optimization of underground cavern excavation and support. Full article

Tetrastigma hemsleyanum Diels et Gilg (T. hemsleyanum) is a prized Chinese medicinal plant renowned for its medicinal and economic importance. In our previous study, a key auxin-related gene ThGH3.1 (encoding amide synthetase) was identified by quantitative transcriptome sequencing. To explore ThGH3.1 function in root development, we generated ThGH3.1-overexpressing and RNA interference (RNAi) transgenic hairy root lines via Agrobacterium rhizogenes (A. rhizogenes)-mediated genetic transformation. The results showed that overexpression of ThGH3.1 significantly inhibited the total length and the lateral root number of hairy roots, accompanied by significantly increased levels of methyl indole-3-acetate (MeIAA) and indole-3-acetyl-aspartate (IAA-Asp). In contrast, ThGH3.1 knockdown displayed an opposite trend. To further confirm the function of ThGH3.1, the overexpression vector was heterologously transformed into wild-type Arabidopsis. After single-copy and homozygous line screening, three overexpressing lines (named G19, G29, and G32) were obtained. The primary root length of transgenic Arabidopsis was significantly shortened, with a significant increase in indole-3-acetonitrile (IAN) levels. Further pot experiments revealed that transgenic Arabidopsis grew more slowly, had significantly smaller leaf areas, and lower plant height. The indole-3-acetic acid (IAA) treatment suggested that ThGH3.1 responded to IAA. Collectively, these findings highlight the crucial roles of ThGH3.1 in regulating root development, which will deepen our understanding of the molecular mechanisms underlying root development in T. hemsleyanum. Full article

The present study investigated the effects of copper oxide nanoparticles (CuO NPs) at concentrations of 0, 5, 10, 20, and 40 mg/L on micropropagation and the accumulation of lipophilic metabolites in Ajuga multiflora, a medicinally valuable ornamental species. The highest number of adventitious shoots (29.4 shoots per explant) was obtained on the shoot induction medium with 5 mg/L CuO NPs. Shoot production gradually decreased at higher CuO NPs concentrations, falling to just 1.1 shoots per explant at 40 mg/L CuO NPs. A similar pattern was seen in axillary shoot multiplication (22.4 shoots per explant at 5 mg/L CuO NPs). However, the maximum shoot fresh weight (0.269 g) was reached on the shoot multiplication medium containing 10 mg/L CuO NPs. Root induction was most effective at 5–10 mg/L CuO NPs, while higher concentrations (20 or 40 mg/L CuO NPs) suppressed or inhibited root formation and altered plantlet morphology. Notably, this study is among the first to assess CuO NPs’ effects across multiple regeneration stages rather than focusing on just one morphogenic event. This emphasizes the importance of optimizing the dose not only for initial shoot induction but also for later multiplication and rooting, ensuring effective micropropagation. Metabolite analysis showed that both the type of organ (microshoots vs. leaves) and CuO NPs concentration significantly affected the levels of α-tocopherol, carotenoids, sterols, and fatty acids. Leaves had higher amounts of α-tocopherol and total carotenoids compared to microshoots. The phytosterol levels also varied, with leaves containing more 22-dehydroclerosterol and total phytosterols, while microshoots had more clerosterol. Treatment with 5 mg/L CuO NPs increased phytosterol accumulation in both organs. CuO NPs significantly influenced the fatty acid profiles. In microshoots, total polyunsaturated fatty acids (PUFAs) increased and total saturated fatty acids (SFAs) decreased with higher CuO NPs levels. Conversely, in leaves, higher CuO NPs concentrations led to increased SFAs and decreased PUFAs, along with a significant rise in the omega-6 (n-6)/n-3 PUFAs ratio. These findings suggest that controlled application of CuO NPs can serve as an elicitor to boost phytochemical production during micropropagation. Full article