Search Results (5,200)

Nickel (Ni) contamination threatens plant growth and ecosystem stability, and plant-growth-promoting rhizobacteria (PGPR) are sustainable bioremediation candidates. Here, we isolated and characterized a Ni-resistant PGPR strain, Microbacterium algeriense C14, from the rhizosphere of Zinnia elegans in Ni-contaminated soil. C14 exhibited exceptional Ni tolerance (up to 800 mg·L⁻¹), produced indole-3-acetic acid (IAA), and maintained pH homeostasis (8.3–8.7). XPS and XRD analyses confirmed a novel carboxylate-based precipitation mechanism: C14 secretes carboxyl-containing metabolites that coordinate with Ni²⁺ to form stable amorphous nickel–carboxylate complexes. Under Ni stress (50–600 mg·L⁻¹ for germination; 50–600 mg·kg⁻¹ soil for pot experiments), C14 inoculation increased the seed germination index by up to 47.3%, seedling root length by 36.9%, and mature plant aboveground fresh weight by 21.32%, while reducing plant Ni uptake by 38.7% (seedlings) and 49.9% (mature shoots). It also enhanced plant antioxidant-enzyme (SOD and POD) activities and soluble protein content, improved soil quality (pH +0.16–0.33 units, urease/acid phosphatase activities elevated), and reduced soil-available Ni by 23.7%. Additionally, C14 enriched Proteobacteria in the rhizosphere and modified microbial community structure. These results highlight M. algeriense C14 as a promising resource for Ni-contaminated soil remediation via integrated metal immobilization, growth promotion, and rhizosphere regulation. Full article

Increasing domestic sewage production associated with urban population growth poses environmental challenges. Biosolids from wastewater treatment can recycle nutrients in agriculture, while plant growth-promoting rhizobacteria (PGPR) enhance nutrient availability and plant performance. This study evaluated the effects of the combined application of sewage sludge–derived biosolid and Bacillus aryabhattai on sunflower growth, biomass production, physiological traits, and nutrient status during the early growth stage under greenhouse conditions. We hypothesized that this combined treatment would enhance plant performance compared with biosolid application alone. Four treatments were established: control (T1), 5 g of biosolid alone (T2), 5 g biosolid + 3.2 mL B. aryabhattai (T3), and 5 g biosolid + 6.4 mL B. aryabhattai (T4). The formulation contains B. aryabhattai strain CMAA 1363 (1 × 10${}^8$ CFU mL${}^{-1}$) as the active microbial component, together with humic substances and other formulation agents (thickener, preservative, and water). The Plants were grown for 44 days. The data were analyzed using one-way ANOVA followed by mean comparison among treatments. Shoot dry mass was significantly higher in T4 compared with the T1 and T2 (p < 0.001), while no significant difference was observed between T3 and T4 (p > 0.05). Biosolid application increased the photosynthetic rate, and its combination with B. aryabhattai further enhanced photosynthetic performance, with significant difference detected between bacterial doses only at the end of growth period. Substomatal CO${}_2$ concentration was lower in inoculated treatments, indicating greater CO${}_2$ assimilation efficiency. Total chlorophyll increased with the addition of sludge and further increased by inoculation with 6.4 mL. Leaf N, Mn, and Zn contents were highest in T4. Overall, the combined application of biosolid and B. aryabhattai improved photosynthetic efficiency and biomass accumulation, highlighting the potential of integrating biosolids and beneficial rhizobacteria as a sustainable approach for nutrient recycling and improved crop productivity in agricultural systems. Full article

The common bean (Phaseolus vulgaris L.cv. BR-104) is the most widely cultivated legume crop and serves as a major dietary protein source worldwide. However, climate change-induced drought poses a severe threat to its productivity by disrupting key physiological and biochemical processes. Therefore, identifying effective strategies to enhance drought resilience in the common bean is of considerable importance. The present study investigates the regulatory role of hydrogen sulfide (H₂S) in improving drought tolerance. Polyethylene glycol (15% PEG) induced drought stress markedly reduced phenotypic changes (leaf area (LA), plant dry weight (PDW), root length (RL), and shoot length (SL) by 18.6, 20.5, 30.3 and 17.5% respectively), photosynthetic efficiency (Fv/Fm by 28.4%), and photosynthetic pigment concentrations (chlorophyll and carotenoids by 25.6 and 36%, respectively), while significantly elevating oxidative stress markers (H₂O₂ and TBARS by 137.1% and 169.8%, respectively), leading to impaired stomatal movement and damaged chloroplast structure. Exogenous H₂S application as sodium hydrogen sulfide (200 µM NaHS; H₂S donor) effectively alleviated drought-induced oxidative damage by boosting endogenous H₂S and GSH levels, upregulating activity of antioxidative enzymes, SOD, APX, and GR, thereby promoting reactive oxygen species (ROS) scavenging, and minimizing lipid peroxidation. Moreover, H₂S maintained photosynthetic efficiency via improved stomatal openings and chloroplast structure, thus sustaining chlorophyll levels and stabilizing photosystem-II functionality. Enhanced proline accumulation following NaHS application led to improved osmotic adjustment, thereby contributing to overall stress tolerance. The use of a H₂S scavenger at 100 µM HT (Hypotaurine) suppressed the mitigating effects of H₂S, confirming the role of H₂S in enhancing drought tolerance in the common bean. Collectively, these findings highlight the potential effect of H₂S as a regulatory signaling molecule to enhance drought resilience in the common bean under drought stress conditions. Further research should explore integrating H₂S-based treatments with breeding programs and agronomic practices to develop sustainable strategies to improve drought resilience in legumes and other staple crops under changing climatic conditions. Full article

Although it is well established that nitrate exerts an inhibitory effect on nodulation and biological nitrogen fixation in soybean, the underlying mechanism remains unclear. In soybean plants, nitrate is assimilated into asparagine (Asn) and glutamine (Gln); their systemic circulation within the plant may contribute to the reduced N-fixation capacity of nodules. To investigate the effects of nitrate, Asn, and Gln on soybean nodulation and biological N fixation, a unilateral nodulated double-root soybean system was used. The non-nodulated side roots were supplied with nitrate (14 mM), Asn (20 mM), or Gln (20 mM), while the nodulated side roots were not supplied with N. Changes in nodule number, nodule dry weight, nitrogenase activity, and N compound content were analyzed after 4 and 10 days of treatment. The results showed that all three exogenous N sources significantly reduced nodule number, nodule dry weight, and nodule nitrogenase activity after both 4 and 10 days of treatment, while promoting the accumulation of ureides, Asn, and Gln in leaves. Nitrate and Asn treatments increased the accumulation of ureides and Asn in nodules, whereas Gln had no significant effect on nitrogenous compounds in nodules. These results suggest that nitrate inhibits nodulation and biological N fixation primarily through its conversion to Asn in soybean plants. The accumulation of Asn in shoots and nodules may suppress nodulation and biological N fixation by promoting ureide accumulation. Full article

Salinity is a major constraint for lettuce production, affecting plant growth, physiological status, and market quality. This study evaluated the combined effects of increasing salinity levels (S₀: non-saline control; S₃₀, S₆₀, and S₁₂₀ mM NaCl) and Trichoderma harzianum inoculation on morphological, physiological, and quality-related traits of lettuce. Increasing salinity levels resulted in significant reductions in growth-related parameters, particularly leaf area, shoot biomass, root volume, and cutting resistance (CR), with the most pronounced decreases observed at S₁₂₀. In contrast, several physiological and quality-related parameters showed different response patterns. Membrane stability index (MSI) and chlorophyll index remained relatively stable across salinity treatments, while total soluble solids (C) increased with increasing salinity, indicating osmotic adjustment under stress conditions. Leaf color parameters showed reductions in lightness and chroma at higher salinity levels, suggesting structural and optical changes in leaves rather than severe pigment degradation. The effects of Trichoderma on plant growth were limited and did not consistently mitigate growth reductions under salinity. However, inoculation influenced several physiological and quality-related traits, including MSI and TSS, indicating a role in physiological regulation and stress adaptation rather than direct growth promotion. Multivariate analyses indicated that salinity was the main factor contributing to treatment separation, whereas Trichoderma application influenced the overall trait profile without consistently increasing growth parameters. Overall, the results suggest that under saline conditions, Trichoderma may contribute to stress tolerance and physiological stability rather than directly increasing plant growth, and its effectiveness depends on stress severity. Full article

To overcome the seasonal constraints of explant availability and facilitate genetic improvement in Catalpa ovata, this study established a dual-pathway in vitro regeneration system (encompassing adventitious shoot organogenesis and somatic embryogenesis) using mature zygotic embryos. We systematically evaluated the synergistic effects of maternal genotypes, plant growth regulators (PGRs), basal media, and the histone deacetylase inhibitor Trichostatin A (TSA). Genotype screening revealed significant divergence in regenerative potential, with the half-sib family 32F17 exhibiting superior responsiveness (84.7% callus induction). A high cytokinin-to-auxin ratio (ZA3 medium) optimally drove direct shoot organogenesis. For adventitious shoot proliferation, the addition of TDZ significantly improved the multiplication coefficient (up to 2.99 on ZB4 medium), although a physiological trade-off with shoot elongation was observed. In parallel, the application of 10 µM TSA significantly enhanced somatic embryogenesis from embryogenic calli, effectively alleviating the inhibitory constraints of exogenous PGRs. For rhizogenesis, the DKW basal medium proved superior to half-strength MS, with the ZE3 treatment (0.1 mg·L⁻¹ NAA + 0.1 mg·L⁻¹ IBA) yielding the highest rooting frequency (69.6%) and robust root architecture. Notably, while somatic embryo conversion remained recalcitrant, plantlets derived exclusively from the adventitious shoot organogenesis pathway were successfully acclimatized ex vitro. These transplanted plantlets exhibited consistently high survival rates (83.1–84.4%) across all tested genotypes, effectively overcoming the initial genotype-dependent recalcitrance. Collectively, this optimized protocol provides a reliable technical platform for the large-scale clonal propagation and biotechnological breeding of C. ovata. Full article

Nitrogen (N) and phosphorus (P) are essential nutrients that play critical roles in plant physiological processes and the accumulation of N and P in broccoli head was significantly correlated with yield. Therefore, there is a need for a rapid, non-destructive diagnosis of crop status by detecting deficiencies in essential nutrients. This study evaluated the effects of N and P deficiency on field grown broccoli (Brassica oleracea L. var. italica Plenk) using a plant-induced electrical signal (PIES) sensor, in which needle electrodes are inserted into the stem to measure electrical conductivity reflecting plant water and ion status. Four treatments were established, including the control (N100P100) with sufficient N and P supply, N deficiency (N0P100), P deficiency (N100P0), and combined N–P deficiency (N0P0). For sufficient supply, urea and fused phosphate (FP) were applied at rates of 122 kg N ha⁻¹ and 71 kg P ha⁻¹, respectively. Soil, stem, and leaf nutrient contents, growth parameters, and stress related indicators were analyzed and their relationship with PIES values were evaluated. PIES was highest in control (N100P100) and lowest under N–P deficiency (N0P0). Higher PIES values were observed during the vegetative stage, whereas values declined during the reproductive stage, reflecting changes in physiological activity. Growth parameters such as shoot and root weight and stem diameter were generally superior in the control (N100P100) treatment, while leaf calcium (Ca), magnesium (Mg), and potassium (K) concentrations showed no significant differences among treatments. Total N content in leaves was higher in N fertilized treatments (control and P deficiency). Photosynthesis-related parameters, including soil plant analysis development (SPAD), Fv/Fm, and chlorophyll content, were lowest under N–P deficiency, which was reflected in the PIES. Principal component analysis (PCA) showed that the PIES was closely associated with growth and photosynthetic parameters and clearly distinguished N sufficient treatments (control and P deficiency) from N deficient treatments (N0P100, N0P0). Overall, these findings suggest that PIES monitoring can serve as a sensitive physiological indicator of nutrient stress and may be applied as an early diagnostic tool before visible growth inhibition occurs in broccoli cultivation. Full article

Background: Konjac (Amorphophallus spp.) is an economically important crop valued for the glucomannan content in its corms. Currently, the konjac industry faces germplasm degeneration due to long-term asexual propagation. Developing tissue culture and genetic transformation techniques is essential for its genetic improvement. The WUSCHEL-related homeobox (WOX) transcription factors are critical regulators of somatic embryogenesis and stem cell maintenance in plants. Methods: In this study, we performed genome-wide identification and characterization of WOX genes in the A. konjac reference genome. Furthermore, comparative transcriptomic analyses and functional verification were conducted in A. bulbifer. Results: A total of 12 AkWOX genes were identified in A. konjac, and their structural features were documented. Comparative transcriptomic analysis of A. bulbifer revealed that AbWOX genes were differentially expressed between embryogenic calli (EC) and non-embryogenic calli (nEC). Notably, AbWOX2 was significantly upregulated in EC. Overexpression of AbWOX2 significantly promoted callus proliferation and shoot regeneration in A. bulbifer. Furthermore, AbWOX2-overexpressing lines exhibited a 5.3-fold increase in genetic transformation efficiency (from 5.12% to 27.31%) compared to the control. Conclusions: We characterized the diverse expression patterns of the WOX gene family in Amorphophallus. Crucially, we identified specific individual members—most notably the markedly upregulated AbWOX2—that function as pivotal drivers of somatic embryogenesis and serve as promising candidates for enhancing regeneration and genetic engineering efficiency in Amorphophallus species. Full article

Soil salinity severely constrains strawberry production by disrupting ion homeostasis and provoking oxidative injury. This study investigated whether soluble silicon (Si) and activated carbon (AC) act to enhance salt tolerance in strawberry (Fragaria × ananassa). Under NaCl stress, plants showed pronounced growth inhibition, increased Na⁺ accumulation and a deteriorated K⁺/Na⁺ balance, accompanied by elevated reactive oxygen species (ROS) and lipid peroxidation. In contrast, combined AC + Si treatment consistently provided the strongest protection, improving seedling vigor and survival. Relative to NaCl alone, AC + Si increased shoot and root fresh weight by 67.5% and 78.5%, reduced shoot Na⁺ by 59.1%, and lowered shoot H₂O₂ and MDA by 62.6% and 66.5%, respectively, indicating marked improvement in ion–redox homeostasis. Beyond plant responses, AC-containing treatments alleviated salt-induced increases in soil electrical conductivity, coinciding with a clear restructuring of the rhizosphere bacterial community and enrichment of putatively beneficial taxa. Transcriptome profiling further supported coordinated reprogramming of ion transport, redox control and stress-responsive signaling pathways under the AC + Si regime. Collectively, the results indicated that Si and AC co-application enhances strawberry salt tolerance through an integrated soil–plant–microbiome mechanism that stabilizes ion homeostasis and reinforces redox homeostasis. Full article

This study evaluated the effects of seven light-emitting diode (LED) spectra on the morphophysiological and plant-quality responses of Korean white dandelion (Taraxacum coreanum Nakai) grown for 30 days under controlled environmental conditions. The treatments included monochromatic red, green, and blue LEDs; a purple-phyto LED containing red, blue, and far-red wavelengths; and three white LEDs (warm white, natural white, and cool white). Morphophysiological responses were assessed together with principal component analysis, correlation analysis, and hierarchical clustering. Green light promoted elongation, increasing shoot height and leaf length, but reduced stem diameter, root length, leaf thickness, biomass accumulation, photochemical performance, and plant quality indices. Red light also resulted in relatively low biomass, SPAD units, F_v/F_m, PI_ABS, normalized difference vegetation index (NDVI), Dickson quality index (DQI), and integrated morphophysiological index (IMI), indicating an imbalanced growth response. In contrast, natural white and cool white LEDs were generally associated with greater stem thickening, root development, leaf thickening, shoot and root dry weight accumulation, and higher F_v/F_m, PI_ABS, NDVI, DQI, and IMI. Warm white showed favorable trends in shoot and root fresh weights and relative moisture content. Multivariate analyses separated the red and green treatments from the white-light treatments. Overall, white LEDs, especially natural and cool white, appeared more effective than monochromatic LEDs in supporting balanced early growth and plant quality in T. coreanum. Full article

The plant-specific TCP transcription factor family plays crucial roles in morphogenesis and stress adaptation. While characterized in many species, this family remains unstudied in Punica granatum. We performed the first genome-wide analysis of the TCP family in pomegranate, identifying 24 PgTCP genes classified into the PCF, CIN, and CYC/TB1 subclades, supported by conserved gene structures and motifs. Evolutionary analysis indicated segmental duplication and purifying selection shaped this family. Expression profiling revealed distinct spatiotemporal patterns: PgTCP2/9/14/21 were highly expressed in flowers, with PgTCP21 also notably abundant in fruit tissues (seed coats and pericarp), suggesting roles in reproductive development. PgTCP19, an ortholog of the branching suppressor BRC1, showed dominant expression in dormant buds, implicating it in shoot architecture regulation. Furthermore, PgTCP5 and the miR319-targeted PgTCP22 were leaf-predominant, indicating a function in leaf development. Under abiotic stress, PgTCPs displayed dynamic, treatment-specific responses. A subset of genes was rapidly induced by cold, while PgTCP14 and PgTCP23 showed sustained upregulation during drought. Several light-responsive PgTCPs were suppressed under shading. This study provides a foundational resource, functionally classifies the PgTCP family, and identifies key candidates regulating organ development and stress resilience for future functional validation and molecular breeding in pomegranate. This work provides the first comprehensive overview of the TCP gene family in pomegranate and offers candidate genes for future functional studies related to development and stress responses. Full article

Pinoresinol diglucoside (PDG), one of the major lignans isolated from E. ulmoides Oliver bark, has various pharmacological functions, including antihypertension and prevention of osteoporosis. However, the glycosyltransferase-encoding gene (GT) involved in regulating the glycosylation of pinoresinol to form PDG has not been reported in E. ulmoides. In this study, we screened and cloned the EuGT8 gene from E. ulmoides based on our transcriptome data. The expression pattern of the EuGT8 gene exhibited a strong positive correlation with dynamic changes in the PDG contents in three different organs of E. ulmoides. The expression level of the EuGT8 gene and PDG content were significantly decreased in asODN-EuGT8-treated shoot tips in comparison with the control group. Prokaryotic expression of the EuGT8 gene revealed that the purified EuGT8 protein could catalyze the conversion of pinoresinol into PDG. In addition, we performed transcriptional and metabolomic analyses to compare the differences between transgenic Arabidopsis and WT plants. A total of 1799 DEGs and 294 DEMs were identified in transgenic and WT plants. KEGG enrichment analysis showed that the DEGs were mainly enriched in phenylpropanoid biosynthesis, secondary metabolite biosynthesis, and starch/sucrose metabolism pathways. The DEMs were mainly enriched in ABC transporters, aminoacyl-tRNA biosynthesis, biosynthesis of amino acids, phenylpropanoid biosynthesis, and flavone and flavonol biosynthesis pathways. Correlation analysis between DEGs and DEMs identified a total of 231 DEGs associated with 38 DEMs, which were mainly distributed in multiple metabolic pathways. This finding provides both theoretical insights and genetic resources for breeding high-PDG E. ulmoides varieties, facilitating marker-assisted selection (MAS) and promoting sustainable E. ulmoides production in Guizhou. Full article

Toxic aluminum (Al) and iron (Fe) alter the hormonal balance of plants, leading to metabolic disorders and growth inhibition. Plants adapt to abiotic stress by optimizing phytohormone biosynthesis. However, the impact of toxic Al and Fe on plant hormonal status is poorly understood. Pea cultivar Sparkle and its mutant E107 (brz), accumulating Al and Fe due to disfunction of metal transporter gene OPT3, were cultivated in hydroponics supplemented or not with 80 µM of AlCl₃ or 300 µM of FeCl₃. Root and shoot biomass of E107 decreased due to Al or Fe treatments approximately by 30%, whereas growth of Sparkle was not affected. The Al and Fe content in the roots and shoots of the metal-treated mutant was circa twice that of Sparkle. Treatment with Al and Fe reduced the content of nutrients (Ca, K, Mg, S) in roots and/or shoots in both genotypes. Compared with Sparkle, untreated E107 possessed lower IAA and higher ethylene and tZR contents in roots but lower GA3, DHZ and tZ content in shoots. Mutant E107 had: lower GA3 and ethylene but higher DHZ, tZ and tZR contents in Al-treated roots; higher ABA, SA, IAA, GA3, DHZ, and tZ contents in Al-treated shoots; lower ABA and SA but higher JA, GA3, DHZ and ethylene contents in Fe-treated roots; higher ABA, SA, IAA, GA3, DHZ, and tZ contents in Al-treated shoots; higher ABA, JA, and GA3 but lower ethylene and tZR contents in Fe-treated shoots. Metal toxicity mainly reduced the content of phytohormones in roots and increased it in shoots. Hormonal disturbances were more significant in E107 than in Sparkle, and the effect of Al was stronger than Fe. Thus, toxic Al and Fe lead to complex, metal- and organ-specific changes in the hormonal status of E107. Hormonal changes might be associated with both defense reactions and the toxic effects of metals on plants. Full article

Heavy metal contamination of freshwater systems represents a persistent environmental challenge due to metal toxicity, non-biodegradability, and bioaccumulation potential. This study compared the phytoremediation performance of Eichhornia crassipes, Pistia stratiotes, and Chrysopogon zizanioides for the removal of chromium (Cr), copper (Cu), cadmium (Cd), and lead (Pb) from contaminated water under controlled conditions. Plants were exposed to aqueous solutions containing 5 mg L⁻¹ of the four metals for 45 days. Metal concentrations in roots and shoots were determined by wavelength-dispersive X-ray fluorescence, translocation factor (TF), bioconcentration factor (BCF), and removal efficiency (RE) were calculated. TF values (0.02–2.90) varied across species, metals, and experimental conditions, indicating a general tendency for metal retention in roots, although translocation to shoots occurred in several cases. BCF values (0.04–87.55) were significantly influenced by species, exposure time, and treatment (p < 0.05), with P. stratiotes showing higher accumulation under specific conditions (Cu = 87.55; Pb = 44.56). In contrast, RE showed high variability (−616.21 to 72.72%) and no significant differences among experimental factors. Overall, the results demonstrate context-dependent variation in metal uptake and translocation, highlighting the potential of aquatic macrophytes as low-cost alternatives for the treatment of metal-contaminated wastewater systems. Full article

Two mineral-based solid residues, namely coal gangue (CG) and phosphorus tailings (PT), two of the largest solid waste streams in the mining industry, were used as the sole metal feedstocks to fabricate a novel MgCaFeAl layered double hydroxide (LDH-GT) via a 700 °C calcination, acid leaching and hydrothermal coprecipitation route, with simultaneous synthesis of white carbon black from the reaction byproducts. Under optimized conditions (total metal load is 150 mg kg⁻¹, LDH-GT dose is 0.09 g, pH from 6 to 7), the synthesized material achieved concurrent immobilization efficiencies of 76.28%, 99.96%, and 99.95% for Cr (VI), Cd (II) and Ni (II), respectively, within a 24 h reaction period. TCLP leachability decreased by 82 to 91% relative to the untreated soil. After three wetting, drying and freeze–thaw cycles, the leached concentrations of all three metals remained below 0.3 mg L⁻¹, confirming excellent long-term stability. Mechanistic analyses revealed that Cr (VI) was mainly sequestered through interlayer anion exchange and surface complexation, whereas Cd (II) and Ni (II) were immobilized via isomorphic substitution into the LDH lattice, precipitation as carbonates, and incorporation into Fe/Mn oxides. A 7-day mung bean bioassay showed that LDH-GT amendment increased seed germination from 50% to 73%, enhanced root and shoot biomass by 1.1- to 1.6-fold, and decreased plant Cr, Cd, and Ni contents by over 80%. The 16S rRNA sequencing further demonstrated that LDH-GT reversed the decline in microbial α diversity induced by heavy metal stress, restored aerobic chemoheterotrophic and sulfur cycling functional guilds, and reduced pathogenic signatures. This study provides the demonstration of a waste-to-resource LDH that achieves efficient, durable remediation of multi-metal-contaminated soils, offering a scalable route for coupling solid waste valorization with in situ site restoration. Full article