Search Results (1,894)

The present study aimed to evaluate the biocontrol and plant growth-promoting potential of putative nitrogen-fixing bacterial strains isolated from the soils of Northern Kazakhstan against major cereal crop phytopathogens and during the early stages of plant development. Phytopathogenic fungi, Fusarium proliferatum and Alternaria alternata, were isolated from infected cereal tissues and seeds using conventional mycological techniques. The antagonistic activity of the bacterial strains was assessed using a dual-culture assay. A total of 26 bacterial isolates were screened for antagonistic activity and plant growth-promoting effects. Several isolates exhibited pronounced inhibitory activity against both pathogens by suppressing fungal mycelial growth. The plant growth-promoting potential of bacterial culture filtrates was evaluated under in vitro conditions using buckwheat (Fagopyrum esculentum Moench) varieties ‘Shortandinskaya 6’ and ‘Shortandinskaya Krupnozernaya’. Germination energy, laboratory germination, shoot length, and root length were recorded during seedling development. The tested bacterial culture filtrates showed a stimulatory effect on seedling growth, with the most pronounced response observed in root elongation, indicating their positive influence on rhizogenesis. The obtained results demonstrate that Agrobacterium pusense st.51S, Ensifer fredii st.59S, and Oricola cellulosilytica st.70S exhibited strong antagonistic activity against Fusarium proliferatum, whereas O. cellulosilytica st.70S, Streptomyces virginiae st.11S, and Ensifer meliloti st.56S effectively inhibited the growth of Alternaria alternata. In addition, E. meliloti st.56S, Priestia megaterium st.35S, Rhizobium giardinii st.2S, and Ensifer sp. st.91S significantly promoted buckwheat seed germination and seedling growth. The most pronounced growth-promoting effect was observed for E. meliloti st.56S, which increased shoot and root length of ‘Shortandinskaya 6’ by 31.4% and 23.8%, respectively, compared with the control. These strains represent promising candidates for the development of microbial bioformulations aimed at improving seed quality, enhancing early plant development, and promoting sustainable crop production under the dry steppe conditions of Northern Kazakhstan. Full article

To investigate the mitigating role and underlying mechanisms of exogenous boron (B) in cadmium (Cd)-stressed woody fruit trees, a hydroponic study was conducted using Malus hupehensis Rehd. seedlings treated with different B concentrations (0, 12.5, 50, and 150 μM H₃BO₃). Cd stress significantly inhibited plant growth and reduced photosynthetic parameters, pigment content, biomass, and root activity, but induced reactive oxygen species (ROS) accumulation. In contrast, the 50 μM B treatment (B2) effectively alleviated Cd toxicity. This treatment significantly decreased Cd accumulation, bioconcentration factor, and translocation factor across tissues. The B2 treatment enhanced Cd immobilization in root cell walls by increasing pectin content and pectin methylesterase activity. Additionally, it shifted Cd chemical forms toward lower-toxicity forms—increasing pectin- and protein-bound, phosphate-bound, and oxalate-bound Cd—while reducing inorganic and water-soluble Cd fractions. The B2 treatment elevated the activities of superoxide dismutase and peroxidase, and increased free proline and ascorbic acid, thereby reducing ROS and malondialdehyde accumulation. The B2 treatment also downregulated key genes including ZIP6 and IRT1 involved in Cd uptake. In conclusion, the most effective concentration among those tested (50 μM) alleviated Cd stress in Malus hupehensis Rehd., accompanied by modified Cd uptake and translocation, enhanced cell wall fixation, altered Cd chemical forms, improved antioxidant responses, and changes in stress-related gene expression. Full article

Nitrogen availability and salinity are two major environmental factors affecting plant growth and development. Nitrate uptake is strictly regulated through transcriptional networks that balance nutrient assimilation and stress responses. The role of BTB-ZF transcription factors, which have been implicated in various abiotic stress responses, in coordinating nitrate uptake remains largely unknown; specifically, the precise molecular mechanisms through which OsBTBZ1, a BTB-ZF transcription factor from Oryza sativa, confers salt tolerance remain to be fully elucidated. Here, we characterize the function of OsBTBZ1 in Arabidopsis thaliana under nitrate and salt stress conditions. Transcriptomic analysis of the bt3 mutant and revertant lines expressing OsBTBZ1 in the bt3 mutant background indicated a relationship with NRT2.1, which encodes a high-affinity nitrate transporter. The bt3 mutant exhibited severe root growth inhibition under low nitrate and salt stress; however, expression of OsBTBZ1 restored root growth under combined stress, supporting a role for AtBT3 in stress adaptation. Our findings suggest that OsBTBZ1 may contribute to the coordination of nitrate-responsive pathways and root plasticity under stress, potentially through regulation of nitrate transport-related processes, including those associated with NRT2.1. These findings highlight the potential of OsBTBZ1-mediated regulatory mechanisms for improving nitrogen use efficiency and stress tolerance in future crops. Full article

Exogenous glutathione (GSH) can alleviate cadmium (Cd) stress, yet physiological improvement and changes in internal Cd burden may not occur in parallel. Salix variegata seedlings were exposed for 10 d to 0 or 100 μM Cd with 0–1500 μM GSH. Across the full dose series, GSH responses were non-monotonic: 10 μM GSH increased root length by 67.3% under Cd stress, 250 μM GSH increased chlorophyll a, chlorophyll b, and total chlorophyll by 21.4%, 39.0%, and 25.7%, respectively, whereas 1500 μM GSH inhibited several growth and pigment traits. A common 2 × 2 subset (0/250 μM GSH × 0/100 μM Cd) was used to integrate root/leaf physiology with root/shoot element status. At 250 μM GSH, H₂O₂ and MDA decreased in both roots and leaves, while antioxidant and osmotic responses differed between tissues. Root Cd concentration increased by 64.1%, root Cd accumulation by 165%, and total Cd accumulation by 117%, despite a 24.1% decrease in shoot Cd concentration. Root Fe concentration and total Fe accumulation increased by 173.2% and 170%, respectively. These results show that GSH responses in S. variegata are dose- and tissue-dependent and that improved physiological status can coexist with greater Cd burden and altered essential-metal homeostasis. Full article

Straw and biochar incorporation are sustainable soil improvement practices to enhance crop productivity. However, the responses of japonica rice to these organic amendments under different planting modes remain unclear in cold regions. A pot experiment was conducted, including two planting methods (transplanting and wet direct-seeding) and three return treatments (straw removal, straw incorporation and biochar incorporation). Rice growth traits, physiology and yield components were investigated. The results showed that wet direct-seeded rice exhibited depressed growth at the reproductive stage, along with smaller root systems and lower root activity, leading to a significant 19.55% yield reduction. Straw incorporation inhibited the early growth for transplanted rice. Biochar incorporation promoted early vegetative growth under both planting modes and significantly increased the activities of nitrogen-metabolism-related enzymes for transplanted rice. Straw and biochar incorporation increased the root bleeding rate and photosynthetic characteristics at the late stage, leading to yield increases of 9.89% and 13.09% for transplanted rice, respectively. No significant yield gains were observed for wet direct-seeded rice. These results indicate that biochar incorporation is an efficient organic returning strategy for transplanted rice, and the responses of japonica rice to straw and biochar incorporation are highly dependent on planting patterns in cold regions. Full article

Sethoxydim, a cyclohexanedione herbicide inhibiting acetyl-CoA carboxylase (ACCase), is widely used for post-emergence control of graminaceous weeds in foxtail millet (Setaria italica (L.) Beauv.) fields. This study investigated under field conditions the effects of sethoxydim on root morphology and rhizosphere microecology using two cultivars with contrasting tolerance: the relatively tolerant hybrid Zhangzagu 10 and the relatively sensitive conventional Zhonggu 19. Previous studies on sethoxydim in foxtail millet have focused primarily on shoot physiology, whereas integrated assessments of root morphology, soil enzyme activity, and rhizosphere microbiome remain scarce. Sethoxydim was applied at 112.5, 225.0, or 337.5 g a.i./hm² (0.5×, 1×, and 1.5× the recommended dose), with water as control. Root morphology and rhizosphere enzyme activities were measured at 0, 7, 14, 21, and 28 days after application, and bacterial and fungal communities were analyzed by high-throughput sequencing. Sethoxydim inhibited root growth in both cultivars, but Zhonggu 19 was consistently more sensitive. At 337.5 g a.i./hm², root length, surface area, diameter, and volume were markedly reduced in Zhonggu 19, whereas Zhangzagu 10 showed milder inhibition and even slight stimulation at lower doses. Rhizosphere urease, sucrase, and catalase activities initially decreased then recovered. Sethoxydim altered α-diversity and community structure of rhizosphere bacteria and fungi. These preliminary findings suggest that sethoxydim may be tentatively applied at or below the recommended dose (≤225.0 g a.i./hm²) under similar field conditions, particularly for tolerant cultivars such as Zhangzagu 10, though confirmation through multi-year trials is required. Full article

Winter oilseed rape (Brassica napus L.) production is constrained by a complex of fungal pathogens, including Alternaria alternata, A. brassicicola, Botrytis cinerea, Phoma lingam and Sclerotinia sclerotiorum, which are conventionally managed with synthetic fungicides such as prothioconazole. This study evaluated the biocontrol and biostimulant potential of two plant extracts (garlic, Allium sativum; Jerusalem artichoke, Helianthus tuberosus) and two bacterial fermentation supernatants (Enterobacter sp. and Paenibacillus sp.) against these pathogens under in vitro, greenhouse and field conditions (2022–2024, two locations: Winna Góra and Rzeszów, Poland). In vitro, the Paenibacillus sp. supernatant showed the broadest and strongest activity, with inhibition of mycelial growth comparable to prothioconazole for several pathogens, particularly A. brassicicola and B. cinerea. Garlic extract was most effective against S. sclerotiorum and B. cinerea, with efficacy increasing with concentration and reaching complete inhibition at 10%; because each concentration was analysed in a separate one-way model, this concentration trend is reported descriptively and was not formally tested as a product × concentration interaction. Jerusalem artichoke extract was consistently the most effective agent against P. lingam (88–92% inhibition, largely independent of concentration), while Enterobacter sp. showed a comparatively narrow spectrum, with no measurable activity against B. cinerea and only negligible activity against S. sclerotiorum (≤6% inhibition at all tested concentrations). In the greenhouse, all four bioproducts significantly stimulated seedling growth, with fresh shoot weight increases exceeding 100% relative to the untreated control; fresh root weight showed a similar but non-significant trend. Under field conditions, garlic extract and Paenibacillus sp. gave the most consistent statistically significant and, in several site-years, fungicide-comparable control of Phoma stem canker (Phoma lingam) and Alternaria black spot (Alternaria spp.), occasionally matching the fungicide Protikon 250 EC; on the other hand, Enterobacter sp. was more variable and Jerusalem artichoke extract intermediate. Seed yield was increased over the untreated control at Rzeszów in both seasons, with the exception of Enterobacter sp. in 2023/2024, but not at Winna Góra, and thousand-seed weight was unaffected by treatment. Full article

Trace elements are essential for plant growth, yet their dose-dependent effects on root system development still remain poorly characterized across diverse plant functional types. We investigated the effects of manganese (Mn), cobalt (Co), and molybdenum (Mo) across 10 concentration gradients (0–500% of standard Hoagland nutrient solution) on root length, tip number, biomass, and activity in four species: Triticum aestivum L., Zea mays L., Ipomoea aquatica Forssk. in Forssk. & Niebuhr, and Canna glauca L. After 30 days of hydroponic culture, our results showed that Mn and Mo elicited significant, concentration-dependent responses across all species. Root traits improved progressively with increasing concentrations from deficiency to optimal levels, but declined when concentrations exceeded the optimal range. The optimal ranges were 25–100% for Mn and 50–150% for Mo, while concentrations above 150% generally proved toxic. By contrast, Co effects were comparatively limited, with significant inhibition only at concentrations exceeding 100%. Species-specific responses were also evident: T. aestivum and Z. mays were more sensitive to Mn and Mo excess, whereas I. aquatica and C. glauca displayed broader tolerance, with C. glauca showing notably high Mo utilization efficiency. Notably, all four root traits exhibited strong positive correlations (r > 0.90, p < 0.001), indicating coordinated morphological and physiological plasticity. Collectively, our findings provide quantitative evidence for species-specific trace element management and contribute to a more nuanced understanding of trace element regulation of root system architecture. Full article

Acetohydroxyacid synthase (AHAS, EC 2.2.1.6) is a core enzymatic target in agrochemical research for herbicide development and has been widely investigated in recent decades. To develop novel AHAS-targeted herbicides, twenty-three acylthiourea derivatives were synthesized via fragment recombination and bioisosteric replacement strategies in this work. All target compounds were fully characterized by elemental analysis, mass spectrometry, FTIR spectroscopy, and ¹H NMR spectroscopy. Dose–response trends from the Petri dish assay at 1, 10, and 100 mg L⁻¹ show that root-growth inhibition increased synchronously with concentration. Preliminary bioassays across gradient concentrations (1, 10, 100 mg L⁻¹) revealed dose-dependent growth-inhibitory effects of several derivatives against the monocot weed Digitaria adscendens and dicot weed Amaranthus retroflexus. At 100 mg/L pre-emergence treatment, compounds 4v (76.48 ± 1.47%), 4m (69.34 ± 1.62%), and 4l (67.77 ± 1.87%) exhibited the strongest inhibitory activity, comparable to or exceeding bensulfuron-methyl (70.41 ± 1.21%). All synthesized acylthiourea derivatives exhibited less than 20% growth inhibition toward wheat and soybean, demonstrating acceptable crop selectivity. In vivo enzymatic assays at 100 mg L⁻¹ showed that 4l, 4m, and 4v achieved AHAS inhibition rates of 38.25 ± 1.81%, 35.74 ± 1.35%, and 38.75 ± 1.93%, comparable to or marginally exceeding that of bensulfuron-methyl (35.64 ± 1.40%). Molecular docking simulations yielded binding energies of −6.67 kcal mol⁻¹ (4l), −6.29 kcal mol⁻¹ (4m), and −6.90 kcal mol⁻¹ (4v), all more favorable than −5.86 kcal mol⁻¹ calculated for bensulfuron-methyl, indicating stronger target-enzyme binding affinity for these three compounds. This research suggests that these acylthiourea derivatives may serve as preliminary lead scaffolds for developing novel AHAS inhibitors via subsequent structural derivatization, pending further dose–response, mechanistic, and field-efficacy validation. Full article

The current challenges associated with the conservation and restoration of plant biodiversity make it necessary to test new biotechnological approaches. Optimizing the stages of clonal micropropagation using synthetic growth biostimulants—protatranes (1,2,3)—enables the targeted modification of physiological processes in plants. This increases their stress resistance, stimulates development, and reduces the cost of the final product. In this paper, the stimulating effect of the protatran (1), which we have named “crezacin”, on the processes of in vitro rooting and acclimatization to ex vitro conditions in microplants of the rare wild species Lilium pensylvanicum Ker Gawl was studied. No effect of crezacin and α-naphthylacetic acid on the development and growth of the microbulb during the rooting stage was detected. Crezacin at a concentration of 1.0 mg/L inhibited root elongation, but did not affect root number. Using α-naphthylacetic acid at a concentration of 0.93 mg/L was ineffective in inducing in vitro rhizogenesis. The survival rate of regenerated plants cultivated on media supplemented with crezacin was found to be 100%. The positive effect of crezacin on the content of photosynthetic pigments in the leaves of regenerated plants was also demonstrated. The addition of ultra-low concentrations (0.001–0.1 mg/L) of crezacin increased pigment content by up to 1.5 times (p < 0.05) compared to the control group. The increase in chlorophyll and carotenoid levels upon the addition of crezacin to the culture medium significantly facilitated the transition from a heterotrophic to an autotrophic mode of nutrition when microplants were transplanted into a soil substrate. Further research on clonal micropropagation of rare plant species and horticultural crops will be conducted using protatranes 2 and 3. Full article

Ginseng (Panax ginseng), a traditional and valuable medicinal plant, is severely affected by rusty root rot caused by Ilyonectria robusta. Xylanase is hypothesized to play a key role in the pathogenicity of I. robusta. Through transcriptomic analysis during ginseng infection, the highly expressed xylanase gene IrXyn01 was identified. A PEG-mediated genetic transformation system for I. robusta was established in this study, with optimized protoplast preparation yielding 1.4 × 10⁷ protoplasts/mL and 36% transformation efficiency. IrXyn01 was successfully knocked out by using the CRISPR/Cas9 method. No significant differences in colony morphology, growth rate, sporulation, and spore germination were observed between mutants and the wild-type stain, indicating IrXyn01 is unrelated to vegetative growth. Under salt stress (KCl and NaCl), mutant inhibition reached 37.2% and 48.2% compared with the wild-type, respectively. The gene also regulated nitrogen source utilization, particularly for ammonium sulfate (29.3% inhibition of the knockout). When xylan was the sole carbon source, ΔIrXyn01 showed 12.8% growth inhibition. Neutral xylanase activity in mutants remained low (35–46 nmol/min/mL), compared to 138–142 nmol/min/mL in the wild-type strain and complemented strains. Pathogenicity assays confirmed that the IrXyn01 knockout significantly reduced disease severity, with lower rusty root rot severity in ginseng inoculated with mutants. This study identified IrXyn01 as a virulence gene in I. robusta and improves our understanding of its molecular pathogenesis. Full article

Canavanine (CAN) is a nonproteinogenic amino acid, synthesised by many legumes (e.g., alfalfa, hairy vetch) and acts as a strong inhibitor of root growth. Thus, CAN may be considered as an allelopathic compound, influencing natural and agroecosystems. CAN is a structural analogue of arginine (Arg), so its toxicity results from its primary mode of action due to interference with Arg-dependent processes, especially incorporation into proteins instead of Arg. The aim of the work was to investigate the impact of CAN (10, 50 µM) treatment (24 or 72 h) on Arg catabolism and content of polyamines (PAs) in the roots of tomato (Solanum lycopersicum L.) seedlings. In the roots of plants cultured in the presence of CAN for 72 h, whosegrowth was completely inhibited, arginase activity and transcript levels of ARG1 and ARG2 were elevated, while ornithine (the product of Arg catabolism by arginase) content was low. CAN application resulted also in decreased total PAs level and increased relative contribution of spermine in the roots of tomato seedlings. CAN-induced alterations in PAs content in the roots were accompanied by changes in transcript levels of genes related to PAs synthesis (SPMS, SPDS) and PAs catabolism (PAO1). Full article

Soil microplastic pollution may affect woody plant establishment, but evidence for tree seedlings remains limited. Populus simonii × P. nigra ‘1307’ seedlings were grown for 45 d in soil containing an equal-mass PVC–PE–PS mixture at 0, 100, 500, or 1000 mg kg⁻¹ dry soil. Growth, root architecture and activity, photosynthetic traits, oxidative status, and soil chemical and enzymatic properties were measured. The 100 mg kg⁻¹ treatment produced limited, trait-specific changes and did not consistently inhibit growth. In contrast, 500 and 1000 mg kg⁻¹ reduced most growth and physiological traits. At 1000 mg kg⁻¹, total dry biomass, total root length, root surface area, root volume, root-tip number, and root activity decreased by 43.7%, 46.5%, 47.2%, 50.2%, 51.1%, and 50.9%, respectively. Net photosynthetic rate and PSII electron transport declined, whereas H₂O₂, O₂•⁻ production, thiobarbituric acid-reactive substances (TBARS), and electrolyte leakage increased. Under higher exposure, soil electrical conductivity was higher, whereas available nutrient levels and several soil enzyme activities were lower. These results indicate that medium and high concentrations of the tested mixture were associated with concurrent inhibition of root development, photosynthetic performance, and biomass accumulation under short-term pot conditions. Because concurrent impairment of woody-seedling performance and soil biochemical functioning may compromise vegetation establishment, these findings support the inclusion of mixed-polymer exposure in ecological risk assessments for soils used in forestry and ecological restoration. Full article

Antimony (Sb) is an emerging environmental pollutant due to its toxicity, persistence, and extensive industrial applications. Despite the growing need for sustainable remediation strategies, research on the potential of phytoremediation for Sb-contaminated soils remains limited. This study investigates the suitability of Cynara cardunculus (cardoon), a high-biomass bioenergy crop, for the remediation of Sb-polluted soils and evaluates the effect of Fe(II) supplementation on plant performance and Sb behavior. Pot experiments were conducted using soils amended with 10–40 mg Sb kg⁻¹, under treatments with and without Fe(II). In the absence of iron, cardoon showed high tolerance to Sb exposure, with no significant growth inhibition even at 40 mg Sb kg⁻¹ after 30 days of cultivation. Iron addition significantly enhanced plant growth, resulting in a 2.3-fold increase in aboveground biomass compared with non-amended soils under the 20 mg Sb kg⁻¹ treatment after 45 days of cultivation. Sb accumulation was mainly restricted to the root system, indicating limited phytoextraction capacity. However, the species demonstrated strong phytostabilization potential, as the presence of plants reduced the water-soluble Sb fraction in soil by up to 50% compared with unplanted controls. These results suggest that C. cardunculus is a promising candidate for phytostabilization of Sb-contaminated soils. Its combined use with iron amendments may enhance biomass production and support integrated soil remediation and bioenergy production strategies. Full article

Arbuscular mycorrhizal fungi (AMF) have been widely recognized for their ability to enhance plant drought tolerance. However, the contribution of improved phosphorus (P) nutrition to AMF-mediated drought tolerance in citrus and its relationship with other physiological processes remain unclear. Here, we investigated the physiological mechanisms underlying AMF-mediated drought tolerance in trifoliate orange (Poncirus trifoliata) by combining AMF inoculation with exogenous phosphorus supplementation under drought stress. AMF inoculation markedly alleviated drought-induced growth inhibition, increased plant biomass, enhanced root and rhizosphere phosphatase activities, promoted phosphorus accumulation, and strongly induced the expression of the mycorrhiza-specific phosphate transporter genes PtaPT4 and PtaPT5. Exogenous phosphorus supplementation largely mimicked the beneficial effects of AMF on plant growth and drought tolerance, indicating that enhanced phosphorus acquisition contributes substantially to AMF-mediated drought tolerance in trifoliate orange. However, the combined application of AMF and exogenous phosphorus conferred greater drought tolerance than phosphorus supplementation alone, suggesting that, in addition to improved phosphorus nutrition, AMF further enhances drought adaptation through the regulation of multiple physiological processes. Furthermore, AMF promoted the accumulation of growth-related phytohormones, enhanced antioxidant capacity, and reduced reactive oxygen species (ROS) accumulation, thereby further improving plant drought tolerance. These findings demonstrate that enhanced phosphorus acquisition is an important component of AMF-mediated drought tolerance in trifoliate orange, whereas coordinated regulation of phytohormone homeostasis and antioxidant defense provides additional protection against drought stress. Full article