Search Results (883)

The chickpea (Cicer arietinum L.) is a key legume crop in Mediterranean agriculture, valued for its nutritional profile and adaptability. However, its productivity is severely impacted by drought stress. To identify microbial solutions that enhance drought resilience, we isolated seven Mesorhizobium strains from chickpea nodules collected in southern Spain and evaluated their cultivar-specific symbiotic performance. Two commercial cultivars (Pedrosillano and Blanco Lechoso) and twenty chickpea germplasms were tested under growth chamber and greenhouse conditions, both with and without drought stress. Initial screening in a sterile substrate using nodulation assays, shoot/root dry weight measurements, and acetylene reduction assays identified three elite strains (ISC11, ISC15, and ISC25) with superior symbiotic performance and nitrogenase activity. Greenhouse trials under reduced irrigation demonstrated that several strain–cultivar combinations significantly mitigated drought effects on plant biomass, with specific interactions (e.g., ISC25 with RR-98 or BT6-19) preserving over 70% of shoot biomass relative to controls. Whole-genome sequencing of the elite strains revealed diverse taxonomic affiliations—ISC11 as Mesorhizobium ciceri, ISC15 as Mesorhizobium mediterraneum, and ISC25 likely representing a novel species. Genome mining identified plant growth-promoting traits including ACC deaminase genes (in ISC11 and ISC25) and genes coding for auxin biosynthesis-related enzymes. Our findings highlight the potential of targeted rhizobial inoculants tailored to chickpea cultivars to improve crop performance under water-limiting conditions. Full article

Manganese (Mn) excess and low pH often coexist in some citrus orchard soils. Little information is known about the underlying mechanism by which raising pH reduces Mn toxicity in citrus plants. ‘Sour pummelo’ (Citrus grandis (L.) Osbeck) seedlings were treated with 2 (Mn2) or 500 (Mn500) μM Mn at a pH of 3 (P3) or 5 (P5) for 25 weeks. Raising pH mitigated Mn500-induced increases in Mn, iron, copper, and zinc concentrations in roots, stems, and leaves, as well as nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, copper, iron, and zinc distributions in roots, but it mitigated Mn500-induced decreases in nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, and boron concentrations in roots, stems, and leaves, as well as nutrient imbalance. Raising pH mitigated Mn500-induced necrotic spots on old leaves, yellowing of young leaves, decreases in seedling growth, leaf chlorophyll concentration, and CO₂ assimilation (A_CO2), increase in root dry weight (DW)/shoot DW, and alterations of leaf chlorophyll a fluorescence (OJIP) transients and related indexes. Further analysis indicated that raising pH ameliorated Mn500-induced impairment of nutrient homeostasis, leaf thylakoid structure by iron deficiency and competition of Mn with magnesium, and photosynthetic electron transport chain (PETC), thereby reducing Mn500-induced declines in A_CO2 and subsequent seedling growth. These results validated the hypothesis that raising pH reduced Mn toxicity in ‘Sour pummelo’ seedlings by (a) reducing Mn uptake, (b) efficient maintenance of nutrient homeostasis under Mn stress, (c) reducing Mn excess-induced impairment of thylakoid structure and PEPC and inhibition of chlorophyll biosynthesis, and (d) increasing A_CO2 and subsequent seedling growth under Mn excess. Full article

Heavy metal-contaminated soil poses a severe threat to environmental quality and human health, calling for eco-friendly and efficient remediation strategies. This study explored the use of biochar-immobilized copper-resistant Pseudomonas aeruginosa to remediate copper-contaminated soil and promote growth of Chinese milk vetch (Astragalus sinicus L.). Indoor pot experiments compared four groups: copper-contaminated soil (control), soil with biochar, soil with free bacteria, and soil with biochar-immobilized bacteria (IM). Results showed IM had the most significant effects on soil properties: it raised pH to 7.04, reduced bioavailable copper by 34.37%, and increased catalase (3.48%) and urease (78.95%) activities. IM also altered soil bacterial communities, decreasing their richness and evenness (alpha diversity) while shifting community composition. For Chinese milk vetch, IM reduced leaf malondialdehyde (a marker of oxidative stress) by 15%, increased total dry weight by 90%, and lowered copper accumulation in roots (18.62%) and shoots (60.33%). As a nitrogen-fixing plant, the vetch’s nitrogen fixation in roots and shoots rose by 82.70% and 57.08%, respectively, under IM. These findings demonstrate that biochar-immobilized Pseudomonas aeruginosa is a promising in situ amendment for remediating copper-contaminated soil and boosting plant growth. Full article

Cadmium (Cd) is a highly toxic heavy metal that can greatly affect crops and pose a threat to food security. Plant growth-promoting rhizobacteria (PGPR) are capable of alleviating the harm of Cd to crops. In this research, a Cd-tolerant PGPR strain was isolated and screened from the root nodules of semi-wild soybeans. The strain was identified as Pseudomonas sp. strain KM25 by 16S rRNA. Strain KM25 has strong Cd tolerance and can produce indole-3-acetic acid (IAA) and siderophores, dissolve organic and inorganic phosphorus, and has 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity. Under Cd stress, all growth indicators of soybean seedlings were significantly inhibited. After inoculation with strain KM25, the heavy metal stress of soybeans was effectively alleviated. Compared with the non-inoculated group, its shoot height, shoot and root dry weight, fresh weight, and chlorophyll content were significantly increased. Strain KM25 increased the superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities of soybean seedlings, reduced the malondialdehyde (MDA) content, increased the Cd content in the roots of soybeans, and decreased the Cd content in the shoot parts. In addition, inoculation treatment can affect the community structure of endophytic bacteria in the roots of soybeans under Cd stress, increasing the relative abundance of Proteobacteria, Bacteroidetes, Sphingomonas, Rhizobium, and Pseudomonas. This study demonstrates that strain KM25 is capable of significantly reducing the adverse effects of Cd on soybean plants while enhancing their growth. Full article

The adoption of biological control strategies plays a crucial role in ensuring the sustainability of organic agricultural practices. A field experiment was conducted in 2023 and 2024 to evaluate the impact of biological treatments using lactic acid bacteria (LAB) Lactiplantibacillus plantarum and mycoparasitic fungus (MPF) Trichoderma virens applied through seed treatment and foliar application separately and in combination on agronomic characteristics and pea yield in organic cultivation. Seed treatment with LAB and MPF resulted in a notable improvement in shoot length and root dry weight, while an increase in root nodule number was observed exclusively with LAB. The combined application of MPF as a seed treatment and LAB as a foliar application at the flowering stage significantly enhanced pod weight per plant, seed number per pod and per plant, and seed weight compared to treatments with LAB applied as either a foliar or seed treatment separately, as well as the untreated control. However, the yield responses to individual and combined treatments under field conditions demonstrated variability and inconsistency. Protein content ranged from 21.24% to 21.61%, and no significant differences observed between treatments. This is the first field report directly comparing the effectiveness of treatments on organic pea production. The findings offer promising avenues for assessing the long-term impacts of these treatments on the sustainable intensification of pea cultivation. Full article

This study investigated the influence of cane diameter on vegetative, productive, and physiological behaviors in Actinidia chinensis, cv. Gold 3. Conducted over two years (2021–2022), the experiment compared canes with larger (HD) and smaller (LD) proximal diameters. This research focused on parameters such as shoot morphology, leaf gas exchange, fruit quality, and hydraulic resistance. The results revealed that HD canes promoted more vigorous growth, with a higher proportion of long and medium shoots, whereas LD canes resulted in shorter shoots. Additionally, the HD canes demonstrated a higher leaf area and more extensive leaf coverage, contributing to enhanced photosynthetic activity, as evidenced by enhanced gas exchange, stomatal conductance, and transpiration rates. This higher photosynthetic efficiency in HD canes resulted in more rapid fruit growth, with a larger fruit size and weight, particularly in fruits from non-terminate shoots. By contrast, fruits on LD canes exhibited slower growth, particularly in terms of fresh weight and dry matter accumulation. Despite these differences, maturation indices, including soluble solids and acidity levels, were not significantly affected by cane type. The findings suggest that selecting HD canes during winter pruning could lead to earlier harvests, with improved fruit quality and productivity, making this practice beneficial for optimizing vineyard management in Actinidia chinensis. Full article

Wheat (Triticum aestivum L.) is a major cereal crop globally, but its production is increasingly threatened by fungal pathogens, particularly Fusarium culmorum (Wm. G. Sm.) Sacc., which causes seedling blight and root rot, leading to yield losses and mycotoxin contamination. Conventional control strategies, such as crop rotation and the use of fungicides, are often inadequate and contribute to the development of resistance, particularly with the overuse of similar modes of action. This study investigated quaternary pyridinium salts—nicotinamide and isonicotinamide derivatives—as potential sustainable antifungal agents. In vivo tests involved treating sterilized wheat seeds grown in sterile sand that had been inoculated with F. culmorum, using compounds previously confirmed to be active in vitro. Disease index, shoot and root length, and fresh and dry biomass were measured. Among the tested compounds, nicotinamide derivatives (2) and (3) showed the lowest disease index (0.9) at a concentration of 10 µg/mL. Most compounds promoted plant and root growth. Isonicotinamide derivatives (6) and (7) at 100 µg/mL increased root dry weight, while compound (6) at 10 µg/mL resulted in the most significant increase in plant length. These findings highlight the dual antifungal and growth-promoting potential of certain eco-friendly derivatives for managing F. culmorum and supporting wheat seedling development. Full article

It is necessary to explore possibilities to increase agricultural production in environmentally friendly ways while maintaining the quality standards of plant raw materials. The effect of amino acids on sweet basil (Ocimum basilicum L.) development may stimulate biomass accumulation and enhance the biosynthesis of secondary metabolites. Investigated varieties “Rosie”, “Red Opal”, “Bordeaux”, “Dark Opal”, “Red Rubin”, “Genovese”, “Cinamon”, “Italiano Classico”, “Marseillais”, and “Thai” were cultivated in a controlled-environment growth chamber and the impact of isoleucine, methionine, glutamine, tryptophan, phenylalanine was studied on biomass accumulation, chlorophyll and phenolic content, and antioxidant activity. Five to six true leaves plants were treated once with an aqueous solution containing 100 mg L⁻¹ of the mentioned amino acids or received no treatment. Our results show that methionine or tryptophan improved the most fresh and dry weight of shoot system of sweet basil plants. Methionine increased chlorophyl a content in 6 of 10 sweet basil varieties, while glutamine had the greatest results in chlorophyl b content. Phenylalanine increased total phenolic content in most treated plants, as well as antioxidant activity. Amino acids may be applied as useful biostimulants in modern agriculture, as they play an important role in ensuring sustainable crop productivity, fostering beneficial plant properties. Full article

The aim of this study was to determine the intraspecific variability among 11 wild-growing populations of wormwood (Artemisia absinthium L.) originating from Central Europe and preserved in the Polish Genebank Collection. The populations were introduced into ex situ conditions, and assessed in terms of selected developmental and chemical traits (essential oil, phenolic acids, polyphenols, and tannins content). Developmental observations and harvest of raw materials were carried out in the second year of plant vegetation, at the beginning of flowering. The populations exhibited significant differences. The greatest variability was observed in the number of shoots per plant (38–51) and dry mass of herb per plant (0.83–1.60 kg). Essential oil (EO) content ranged from 0.75 to 1.69 g/100 g dry weight (DW). A total of 41 compounds were identified in the EOs, with oxygenated monoterpenes (such as sabinyl acetate, cis-chrysanthenol, chrysantenyl acetate, 1,8-cineole, α- and β-thujone) as dominants, showing considerable variation among populations. Based on the EO profiles, several chemotypes were distinguished, mainly (1) a pure sabinyl acetate chemotype; (2) mixed chemotypes with sabinyl acetate accompanied by β-myrcene, cis-chrysanthenol, chrysanthenyl acetate, or 1,8-cineole; and (3) a thujone chemotype. The total content of phenolic acids (expressed as caffeic acid equivalent), tannins, and polyphenols (as pyrogallol equivalent) varied significantly, too (0.37–0.50; 0.10–0.26; 0.58–0.79%, respectively). The results confirm a high level of intraspecific variability in both developmental and chemical traits of A. absinthium populations originating from Poland. This diversity may be valuable for future breeding programs and for the selection of populations with desired phytochemical profiles for medicinal, food, and agricultural applications. It is worth noting that the floristic diversity among populations indicates the habitat heterogeneity, ranging from natural or semi-natural (populations 1, 6) to more anthropogenically influenced ones (populations 2, 4, 5, 7–11). Full article

Four biostimulants (phycocyanin, γ-aminobutyric acid (GABA), glycine betaine (GB), and the mycorrhizal fungus Rhizophagus intraradices) were applied foliarly to six cultivars of mature creeping bentgrass (Agrostis stolonifera) under non-stressed greenhouse conditions. Phycocyanin was most effective at increasing total shoot greenness, which was most consistent over time with the cultivars Penncross, T1, and Tyee. GABA was most effective at increasing total root fresh and dry weight, most strongly for Penncross and T1, respectively. GB was most effective at increasing total shoot fresh and dry weight, with both most strongly increased for Tyee. By comparison, R. intraradices had relatively low effectiveness for increasing any of these parameters. The appearance of the grass at the end of the experiment revealed that 007 and Focus generally showed the most and least growth benefit, respectively, with all four biostimulants. However, all cultivars showed increases in more than one parameter for each biostimulant, and thus, no cultivar was uniformly responsive or non-responsive to all the biostimulants. This research shows that phycocyanin, GABA, and GB may benefit multiple creeping bentgrass cultivars under non-stressed conditions, but each one tended to be more beneficial to a particular aspect of plant growth and quality. End users need to be aware of the importance of creeping bentgrass genotype when considering biostimulant application. Full article

Weak seedlings and poor growth uniformity affect the mechanical transplanting of densely sown rice seedlings. To address these issues, seedlings of the conventional japonica rice “Zhehexiang 2” were grown in a traditional flat tray (control), pot-mat tray (26 × 52 bowls; BT(26)), and pot-mat tray (30 × 58 bowls; BT(30)) to compare the effects of different specifications of pot-mat trays (BTs) on the growth and quality of mechanical transplanting of densely sown rice seedlings with 250 g/tray. The BT-raised seedlings showed improved seedling quality, with increases in the shoot and root dry weights by 7.44% and 20.11%, respectively, compared to the flat tray. Under the dense sowing rate, the plant height uniformity of the BT(26) and BT(30) treatments was significantly increased by 6.95% and 3.43%, and the root entwining force of the seedlings was 14.28% and 10.21% higher, respectively, compared with those of the control. The missing hill rate for BT-raised seedlings after mechanical transplanting was significantly reduced by 53.15%. The loss of roots during mechanical transplanting was reduced. Compared with the control, the root length, root surface area, and root number were increased, and a greater number of large roots were retained, which promoted the early development of seedlings after mechanical transplanting. The proportion of holes with two to five seedlings was higher after mechanical transplanting. The pot-mat tray divided the root growth area of seedlings, promoted the growth of the seedlings, and reduced the root loss and missing hill rate under the high sowing rate. Thus, the quality of mechanical transplanting of densely sown seedlings was improved. Full article

The demand for sustainable agriculture has prompted the exploration of alternative methods to boost crop growth and yield. Microbial biostimulants offer effective solutions to enhance plant performance and reduce reliance on chemical fertilizers. This study investigated the effects of Bacillus pumelo (B. pumilus), applied individually and in combination with a mycorrhizal fungi complex, on the growth, yield, and photosynthetic activity of pea (Pisum sativum). Pea seeds were grown in sterilized soil under four treatment conditions, including a non-inoculated control, inoculation with 2.5 mL of B. pumilus culture per seedling, inoculation with an indigenous mycorrhizal fungal complex, and a combined treatment of B. pumilus and the mycorrhizal complex. The biostimulant treatments significantly influenced all measured photosynthetic and growth parameters. The results showed that B. pumilus substantially promoted pea growth, leading to notable improvements in biomass, plant height, and photosynthetic efficiency. When combined with the mycorrhizal fungi complex, these growth-promoting effects were significantly amplified, resulting in a ~69.7% increase in shoot fresh weight, a ~72.7% rise in root dry weight, and a ~73.6% boost in flower production. Additionally, the chlorophyll content increased by ~180% and photosynthetic yield (Fv/Fm) improved by ~18.5%. The combined treatment also produced the highest SPAD index value, reflecting a ~57% increase. The synergistic interaction between B. pumilus and mycorrhizal fungi enhances photosynthetic efficiency and overall plant performance. The study highlights the potential of using these microbial inoculants as biostimulants to improve pea cultivation in agroecosystems, offering a sustainable alternative to chemical fertilizers. Full article

Despite chemical exchange often serving as the first step in plant–microbe interactions, the specialized chemical metabolites produced by grass–Epichloë endophyte symbiosis as mediators of host growth, nutrient acquisition, and modulators of the rhizosphere community under low-nitrogen conditions are areas lacking in knowledge. In this study, we investigated the plant growth-promoting effects of the Epichloë endophyte strain and identified the growth of the Epichloë strain under different types of nitrogen source treatments. In addition to the in vitro test, we evaluated growth performance for Epichloë endophyte–infected plants (E+) and Epichloë endophyte–free plants (E−) in a pot trial under 0.01 mol/L urea treatment. Seedlings from E+ and E− groups were collected to analyze the plant bacterial microbiome and root metabolites. The E. gansuensis endophyte strain was found not to produce indoleacetic acid (IAA), pectinase, or contain ferritin. The nitrogenase gene, essential for nitrogen fixation, was also absent. These results suggest that E. gansuensis endophyte strains themselves do not contain attributes to promote plant growth. Concerning N fertilization, it was observed an increase in the colony diameter of E. gansuensis strain was observed only in the NO₃⁻-N (NN) treatment, while inhibition was observed in the urea-N (UN) treatment. E. gansuensis endophyte symbiosis significantly increased tiller number and plant dry weight. Overall, our results suggest that the E+ plants had more root forks and greater average root diameter compared to E− plants under the UN treatment. In a pot experiment using UN, data from 16S rRNA amplicon sequencing revealed that E. gansuensis endophyte infection significantly altered the bacterial community composition in shoot and root, and significantly increased Shannon (p < 0.001) and Chao 1 (p < 0.01) indexes. The relative abundance of Acidobacteriota, Actinomycetota, Cyanobacteriota, Fibrobacterota, Myxococcota, and Patescibacteria in the shoot, and Cyanobacteriota, Pseudomonadota, and Verrucomicrobiota in the root were significantly increased by E. gansuensis endophyte infection. Similarly, E. gansuensis endophyte symbiosis shifted the metabolite composition of the host plants, with the E+ plants showing a higher number of metabolites than the E− plants. In addition, co-metabolism network analysis revealed that the positive relevance between exudates and microorganisms in the root of the E+ plants is higher than that of the E− plants. These findings provide valuable insights into the knowledge of the effects of the symbiotic relationship between host plants and Epichloë endophyte on interspecific interactions of plant microbiome, beneficial for harnessing endophytic symbiosis, promoting plant growth. Full article

This study investigated the phytochemical content of melon sprouts obtained from by-product seeds of fruit processing and the elicitation effect obtained by the application of salinity to the growing substrate. Seeds from two melon Cultivars (Thales and SV9424ML) were sprouted at 0, 12.5, 25, and 50 mM NaCl concentrations (Salt). Due to intra-lot seed variability in germination speed, sprouts were harvested at 1 and 2 weeks after sowing (WAS), included as an experimental factor (Harvest), collecting, at each harvest, only those that had reached the ready-to-eat stage. Seed germination, shoot and root lengths, fresh and dry weights, and their content in phenolic compounds were determined. Cultivar, Harvest, and Cultivar × Harvest interaction affected sprout phenolic compound content more than Salt. In general, Thales exhibited a significantly greater phenolic compound content (+67.9%, on average). Harvest influenced phytochemicals, with sprouts at 2WAS exhibiting lower flavonoid and hydroxybenzoic acid levels (−31.3% and −73.0%, respectively), yet higher hydroxycinnamic acid content (+298.6%). This was a consequence of variations in p-coumaric and ferulic acids at 2WAS and in flavonoids at 1WAS. Moreover, Salt had an appreciable effect only on Thales, at moderate levels (25 mM NaCl). Our results suggest that the sprouting of by-product seeds of vegetables should be finely modulated based on the seed intra-lot variability in germination speed and on cultivar responsiveness to salinity for phytochemical elicitation. Full article

A bioassay study was conducted to determine the differences in the sensitivity of selected crops to simulated clomazone residues (nine concentrations were used ranging from 5.625 to 1440 μg a.i./kg soil). White mustard was the most susceptible as measured by shoot fresh weight (SFW) and shoot dry weight (SDW) inhibition, with EC₅₀ values of 94.6 and 128.2 μg a.i./kg soil, respectively. Regarding the EC₅₀ values for the inhibition of pigment content (carotenoids, chlorophyll a and chlorophyll b), sugar beet and white mustard showed a high sensitivity, as the EC₅₀ values for all three pigments were in the range of 45.8–47.4 and 57.5–63.3 μg a.i./kg soil, respectively. However, as the SFW and SDW of sugar beet were only reduced at the three highest clomazone concentrations applied, white mustard proved to be the most sensitive crop. Wheat was less sensitive (EC₅₀ = 214.4–243.8 μg a.i./kg soil, for all three pigments), while sunflower and maize were the least sensitive (EC₅₀ = 359.7–417.5 and 456.1–535.8 μg a.i./kg soil, respectively). Field trials were conducted for two years in the Srem region to study the dynamics of clomazone degradation in sandy loam soil. Clomazone was applied pre-plant incorporated (PPI) and post-emergence (POST-EM) in three doses: 480, 720 and 960 g a.i./ha. Soil samples were taken at regular intervals from the day of herbicide application until one year after application and residue concentrations were determined using the white mustard bioassay (based on the measurement of carotenoid content inhibition). The application rate had no consistent effect on the persistence of clomazone. Slower degradation was observed in the PPI treatment than in the POST-EM treatment (8.5 and 15 days longer average half-lives in the first and second year, respectively). Persistence was affected by lower rainfall, resulting in a longer half-life in the second year (12 days on average). Herbicide residues caused no visible injury to white mustard one year after application, while the reduction in carotenoid content ranged from 0.37 to 22.89%, indicating that no injury can occur to any of the tested crops one year after application of clomazone in sandy loam soil. Full article