Increased Root Length Research Articles

Managing tomato bacterial wilt through pathogen suppression and host resistance augmentation using microbial peptide

The increasing health and environmental risks associated with synthetic chemical pesticides necessitate the exploration of safer, sustainable alternatives for plant protection. This study investigates a novel biosynthesized antimicrobial peptide (AMP) from Lactiplantibacillus argentoratensis strain IT, identified as the amino acid chain PRKGSVAKDVLPDPVYNSKLVTRLINHLMIDGKRG, for its efficacy in controlling bacterial wilt (BW) disease in tomato (Solanum lycopersicum) caused by Ralstonia solanacearum. Our research demonstrates that foliar application of this AMP at a concentration of 200 ppm significantly reduces disease incidence by 49.3% and disease severity by 45.8%. Scanning electron microscopy revealed severe morphological disruptions in the bacterial cells upon exposure to the AMP. Additionally, the AMP enhanced host resistance by elevating defense enzyme activities, leading to notable improvements in plant morphology, including a 95.5% increase in plant length, a 20.1% increase in biomass, and a 96.69% increase in root length. This bifunctional AMP provides dual protection by exerting direct antimicrobial activity against the pathogen and eliciting plant defense mechanisms. These findings underscore the potential of this biologically sourced AMP as a natural agent for combating plant diseases and promoting growth in tomato crops. To the best of our knowledge, this is the first study to demonstrate the use of a foliar spray application of a biosynthesized microbial peptide as biocontrol agent against R. solanacearum. This interaction not only highlights its biocontrol efficacy but also its role in promoting the growth of Solanum lycopersicum thereby increasing overall agricultural yield.

Esterilización de la lesión y reparación tisular con Pasta CTZ en molar permanente con pulpitis irreversible.

advocates the use of an antibiotic mixture instead of root canal instrumentation. Case Report: A 9-year-old female patient sought consultation for spontaneous pain associated with tooth 36, with a sudden and pulsatile onset, which decreased with analgesics and increased at night, during chewing, with thermal and mechanical stimuli, hindering detailed tooth brushing. Clinically, the tooth presented marked opacities associated with an active and cavitated dental caries lesion and post-eruptive fracture. Radiographically, a radiolucent image was observed in the furcation region with open apices and radiolucent areas in the mesial and distal roots. Tooth 36 was diagnosed with severe Molar-Incisor Hypomineralization (MIH) + symptomatic irreversible pulpitis and symptomatic apical periodontitis. LSTR therapy was performed using a triantibiotic paste based on chloramphenicol, tetracycline, and zinc oxide and eugenol (CTZ Paste). The tooth was restored with a preformed stainless-steel crown using the modified Hall technique. Over the 24-month follow-up, the patient reported no painful symptoms, and no signs of inflammation or infection were observed. Radiographically, there was an increase in root length, apical closure, and bone repair in the furcation and periapical regions. Conclusion: LSTR therapy with CTZ Paste was effective in the treatment of a first permanent molar with irreversible pulpitis.

Impact of Neem-Coated Urea on NO₃-N and NH₄-N Availability and Growth Performance of Maize in Saline and Non-Saline Soils

This study investigates the effects of neem-coated granular urea on nitrogen volatilization and leaching in maize (Zea mays L.), focusing on nutrient availability (NO3-N and NH4-N) in both normal and saline soils. The pot experiment was conducted in a glass-panelled wire house CRD design with three replications. The experimental treatments included T1 (control without fertilizer), T2 (0.05 % neem-coated granular urea @ 200 kg ha⁻¹ + recommended P and K), T3 (0.08 % neem-coated granular urea @ 200 kg ha⁻1 + recommended P and K), T4 (0.01 % neem-coated granular urea @ 200 kg ha-1 + recommended P and K), and T5 (recommended NPK: 200 kg N ha⁻¹, 90 kg P₂O₅ ha⁻¹, and 60 kg K₂O ha⁻¹). Soil samples were taken prior to planting, one month later, and following harvest in order to examine key chemical components. The results demonstrated that maize growth and nutrient uptake were significantly enhanced by T3 (0.08 % neem-coated urea). Under T3, there was an increase of 34.32 % in shoot length, 50.48 % in fresh weight, and 22.40 % in dry weight. There were notable increases in root length, fresh weight, and dry weight of 36.68 %, 21.32 %, and 46.53 %, respectively. Additionally, in comparison to the control, the T3 treatment increased the plant membrane stability index (MSI), chlorophyll content, and nitrate retention by 21.32 %, 22.13 %, and 17.29 %, respectively. Treatment T3 enhanced potassium content, phosphorus absorption, and nitrogen concentration. According to data, applying 0.08 % neem-coated urea along with recommended levels of potassium and phosphate enhances maize growth, and overall crop productivity. This makes it a feasible substitute for long-term and effective fertilizer application in both normal and salinized soils.

Co-exposure Impact of Nickel Oxide Nanomaterials and Bacillus subtilis on Soybean Growth and Nitrogen Assimilation Dynamics.

Nickel oxide nanoparticles (NiO-NPs) pose potential threats to agricultural production. Bacillus subtilis has emerged as a stress-mitigating microbe that alleviates the phytotoxicity caused by NiO-NPs. However, the mechanisms underlying its effectiveness, particularly in root-nodule symbiosis and biological N2-fixation (BNF), remain unclear. Here, we tested the combined exposure of NiO-NPs (50 mg kg-1) and B. subtilis on soybean (Glycine max L.) growth and BNF. Combined exposure increased root length, shoot length, root biomass, and shoot biomass by 19-26%, while Ni (200 mg kg-1) reduced them by 38--53% compared to the control. NiO-NPs at 100 and 200 mg kg-1 significantly (P < 0.05) reduced nodule formation by 16% and 58% and Nitrogen assimilation enzyme activities levels (UE, NR, HS, and GOGAT) by 13-57%. However, co-exposure with B. subtilis improved nodule formation by 22-44%. Co-exposure of NiO-NPs (200 mg kg-1) with B. subtilis increased POD, CAT, and GSH-Px activity levels by 20%, 16%, and 14% while reducing MDA (14%) and H₂O₂ (12%) levels compared to NiO-NPs alone. Additionally, co-exposure of NiO-NPs (100 and 200 mg kg-1) with B. subtilis enhanced the relative abundance of Stenotrophomonas, Gemmatimonas, and B. subtilis, is associated with N2-cycling and N2-fixation potential. This study confirms that B. subtilis effectively mitigates NiO-NP toxicity in soybean, offering a sustainable method to enhance BNF and crop growth and contribute to addressing global food insecurity.

Engineering seed microenvironment with embedded bacteriophages and plant growth promoting rhizobacteria

BackgroundEngineering the seed microenvironment with embedded bacteriophages and Plant Growth Promoting Rhizobacteria (PGPR) shows promise for enhancing germination, mitigating biotic and abiotic stressors, and improving resilience under challenging environmental conditions. This study aimed to enhance potato seed germination and control bacterial wilt caused by Ralstonia solanacearum and salinity by using novel technology to encapsulate, preserve, and deliver phage therapy and rhizobacteria.ResultsSilk fibroin and trehalose biomaterial combined with the phage P-PSG11 and Pseudomonas lalkuanensis were applied to potato seeds. A pot experiment was conducted to investigate pathogen suppression, salt tolerance, and plant growth enhancement. The combination of silk and trehalose effectively preserved both phage and bacteria for ≥ 8 weeks, maintaining both phage titers and bacterial colony counts. Seeds coated with the P-PSG11 and P. lalkuanensis mixture exhibited the highest germination rate at 93.5%, followed by P. lalkuanensis at 86.3%. In vivo evaluations showed significant increases in root length (72.7%, 61.0%, and 22.5%), plant height (71.5%, 65.1%, and 8.2%), and dry matter (129.1%, 125.7%, and 13.1%) for the P-PSG11 and P. lalkuanensis mixture, P. lalkuanensis, and P-PSG11, respectively. The incidence of wilt was significantly reduced by 88.2% and 81.2%, and salinity was mitigated by 83.3% and 79.2% for the P-PSG11 and P. lalkuanensis mixture and P. lalkuanensis treatment, respectively, compared to the control (p < 0.001). The viability of preserved P-PSG11 and P. lalkuanensis was confirmed after one year using phage titers and bacterial colonies.ConclusionThis innovative approach enhanced plant growth, promoted seed germination, controlled wilt disease, and mitigated soil salinity.

Rhizosphere bacteria from the Bolivian highlands improve drought tolerance in quinoa (Chenopodium quinoa Willd.).

Drought is one of the most destructive abiotic factors for agricultural production, causing considerable yield losses. Quinoa (Chenopodium quinoa Willd.) is cultivated worldwide in different environmental conditions due to its nutritional characteristics and ability to grow in harsh environments. This study aims to select drought stress tolerant rhizosphere bacteria from the Bolivian altiplano to evaluate their quinoa growth-promoting capacity, including in vitro germination, seedling growth under drought stress in greenhouse conditions and field studies. Rhizosphere soil from the southern highlands of Bolivia was collected to isolate 164 drought-stress tolerant bacteria. From these, 28 strains were shown to produce indole acetic acid, and/or to possess nitrogen-fixing or phosphate solubilizing capacity under in vitro conditions. Furthermore, all strains were evaluated for improvement of in vitro quinoa seed germination. Based on these properties, nine bacterial strains were formulated in three different matrixes and evaluated for quinoa seedling growth promotion during drought stress in a three-month greenhouse experiment. Three strains were shown to significantly (P < 0.05) increase root length of the quinoa seedlings. One strain was selected and shown to significantly (P < 0.05) increase leaf number in a field trial under semi-arid conditions in the southern altiplano in Bolivia. DNA sequencing and phylogenetic analyses of the 16S locus putatively identified the three strains with growth-promoting potential under drought stress as members of the genera Bacillus, Pseudomonas and Serratia. Microorganisms from the arid Bolivian altiplano constitute a potential biological source of bioinoculants to improve quinoa productivity and provide sustainable mitigation of climate change effects.

Altering endogenous cytokinin content by GmCKX13 as a strategy to develop drought-tolerant plants

Climate-resilient crops are essential to meet the growing food demands of an ever-increasing world population. The phytohormone cytokinins (CKs) have been well established to regulate plant adaptation to drought. Previously, we reported that GmCKX13, encoding a CK oxidase/dehydrogenase in soybean (Glycince max), was differentially expressed under drought. Here, we further characterized its in planta function to assess if GmCKX13 could be a candidate gene to develop drought-tolerant crops. Transgenic Arabidopsis 35S:GmCKX13 plants ectopically and constitutively expressing GmCKX13 using the 35S promoter had an increase in root length, while showing a reduction in shoot height and biomass. CK contents were reduced in 35S:GmCKX13 plants, coupled with the reduced expression of all AtCKX genes and increased expression of all Arabidopsis isopentenyl transferase (AtIPT) genes, except AtIPT2 and AtIPT9 that are responsible for the production of cis-zeatin-type CKs. The 35S:GmCKX13 plants showed improved tolerance to drought and more sensitivity to the treatment with exogenous abscisic acid (ABA). Under the control of the drought-responsive promoter RD29A, the transgenic RD29A:GmCKX13 Arabidopsis plants had a similar phenotype as that of the wild-type (WT) plants under normal conditions. Under dehydration, we found a significant increase in the expression of the transgene coupled with a higher leaf relative water content in RD29A:GmCKX13 plants when compared with WT plants. In consistence with this finding, the RD29A:GmCKX13 plants exhibited higher survival rates and 30 % higher seed yield than the WT plants under drought conditions. Taken together, our results demonstrated that GmCKX13 is an excellent gene for developing drought-tolerant crops by altering endogenous CK levels and ABA responsiveness when being driven by a drought-responsive promoter.

Light Drought Stress Positively Influenced Root Morphological and Endogenous Hormones in Pinus massoniana Seedlings Inoculated with Suillus luteus

Aims An ectomycorrhizal fungus (ECMF) may enhance plant drought resistance. However, there is limited information regarding the effects of ECMFs on drought resistance in Pinus massoniana Lamb., a native species representing an afforestation pioneer tree in subtropical regions of China. Methods In this study, a pot experiment was conducted to determine the effects of ECMF Suillus luteus inoculation on the root morphology and endogenous hormones of P. massoniana, including roots, leaves, and stems, under various water treatment conditions. Four water levels (regular, light, moderate, and severe drought) and three inoculations (inoculated Suillus luteus, numbered S12 and S13, and non-ECMF-inoculated) were compared using a factorial design. Results Under drought stress, P. massoniana seedlings inoculated with S12 and S13 had significantly increased root morphology development (p &lt; 0.05). Light drought positively influenced root development, resulting in a more than twofold increase in root length and root surface area compared to non-inoculated seedlings. Concentrations of gibberellic acid (GA), zeatin riboside (ZR), and indole-3-acetic acid (IAA) in roots, stems, and leaves of inoculated S12 and S13 plants were elevated, whereas abscisic acid (ABA) concentrations were significantly lower, compared to non-inoculated seedlings. The ABA concentrations in the roots of S12 and S13 inoculated seedlings under light drought stress were 1.5 times lower than those in non-inoculated controls. Moreover, root development was positively correlated with plant total GA, IAA, and ZR but negatively correlated with ABA. ConclusionsS. luteus can promote the root growth and development of P. massoniana seedlings, notably by regulating the balance in the concentration of endogenous hormones, thus improving the drought resistance of P. massoniana seedlings.

Evaluation and identification of metabolites produced by Cytobacillus firmus in the interaction with Arabidopsis thaliana plants and their effect on Solanum lycopersicum

Currently, the use of bio-inputs is increasing due to the need to reduce the use of agrochemicals. However, one of the limitations is to preserve the viability of the living microorganisms, so it is important to find an alternative that allows us to obtain different metabolites to produce it. We evaluated three different interactions (contact, diffusible and volatile compounds) in vitro in Arabidopsis thaliana (At) seedlings with the strain Cytobacillus firmus M10 and its filtered secondary metabolites (M10F). The results showed that the seedlings inoculated by contact with the filtrate (AtM10F) presented increases in root length (30 %) and leaf area (33 %), as well as in the volatile interaction (At/M10F) with respect to the uninoculated treatment. For both interactions, the seedlings inoculated with the bacteria by contact (AtM10) and volatile (At/M10) obtained greater biomass (48 and 57 %). Subsequently, an evaluation at the end of the A. thaliana cycle showed that the treatments obtained by contact and distance when reinoculated with the bacteria and the filtrate (AtM10, At-M10 and AtM10F) obtained 50 % more seed yield than the control treatment, while AtM10F presented 72 %, while At/M10F presented the highest no. of siliques and seeds, which increased the yield by 65 %. In the Solanum lycopersicum (Sl) experiment, the filtrate (SlM10F) showed significant differences in seedling height, leaf length and width (23, 24 and 36 %, respectively). It also promoted an increase in fresh and dry weight, producing a greater root area and larger leaves compared to the control (Sl) and the bacteria (SlM10). We performed a qualitative characterization of the secondary metabolites present in the filtrate, where we found 2,4-DTBP, sylvopinol, isophthaladehyde, and eicosane of interest with possible growth-promoting effects on A. thaliana and tomato. We identified volatile compounds present in plant-microorganism and plant-filtrate interactions as possible precursors in the induction of plant growth, among which phenols, alcohols, aldehydes, alkanes, and alkenes stand out. Most of the analyzed compounds have not been found in the literature with reports of growth promoters, is important to mention that due to their characteristic functional groups they can derive and trigger the synthesis of new molecules with agronomic application.

A New Approach for Analyzing Root Development in Autogenous Tooth Transplants Using Computed Tomography.

The aim of this study was to evaluate root development in autotransplanted teeth using cone-beam computed tomography (CBCT) images. Twelve premolars with incomplete root formation, which were selected to replace prematurely lost upper central incisors, were analyzed by CBCT on two different occasions. The first CBCT examination (T1) was conducted before tooth autotransplantation. The second CBCT examination (T2) was performed over a follow-up period of at least 12 months and < 5 years. Three previously calibrated evaluators assessed root development. The positions of the tomographic planes were standardized. The mean root length in sagittal and coronal tomographic sections was used to validate the root length at T1 and T2. Longitudinal root development of the transplanted tooth was determined by calculating the difference in root length between T2 and T1. The intraclass correlation coefficient (ICC), paired t-test, and Pearson test were applied, with significance set at 5%. The mean time elapsed between T1 and T2 was 962 days/2.6 years. The ICC was > 0.75. The measurements obtained at T2 were significantly greater than at T1 (p = 0.001). The mean increase in root length was 2.83 mm. There was no significant correlation (p = 0.413; r = 0.261) between root length increase and the time elapsed between T1 and T2. Premolar teeth with incompletely formed roots transplanted to the upper central incisor region showed continued root development during postoperative follow-up.

Modulatory effects of glutamic acid on growth, photosynthetic pigments, and stress responses in olive plants subjected to cadmium stress

Cadmium (Cd) is a toxic heavy metal that severely impacts plant growth and photosynthesis and induces oxidative stress. This study investigates the modulatory effects of glutamic acid (GA) on Olea europaea (olive) seedlings subjected to cadmium stress. The experiment included control, Cd-stressed, GA-treated, and combined Cd and GA-treated groups. Cd exposure significantly reduced plant growth, as evidenced by decreased root length (3.5 cm) and shoot length (9 cm) compared to control plants (5 cm and 12 cm, respectively). Additionally, Cd stress led to a reduction in chlorophyll content (16.2 mg/g fresh weight) and elevated oxidative markers like H2O2 and MDA. The application of GA significantly improved plant growth and physiological parameters, with statistically significant increases in root length (up to 6.5 cm) and shoot length (up to 14 cm) in the combined treatment group (p ≤ 0.05). Furthermore, GA treatment led to a marked elevation in total chlorophyll content (up to 27.5 mg/g fresh weight), compared to 16.2 mg/g in Cd-stressed plants (p ≤ 0.05), reflecting a significant improvement in photosynthetic efficiency. GA also elevated the antioxidant enzyme activity catalase (CAT) and peroxidase (POD), reducing oxidative stress by decreasing hydrogen peroxide and MDA levels. The findings suggest that glutamic acid effectively mitigates Cd-induced phytotoxicity, enhancing stress resistance and promoting plant growth. This research provides valuable insights into using glutamic acid as a possible approach to mitigate heavy metal stress in plants, offering implications for agriculture and environmental management in Cd-contaminated areas. Specific applications may include its use in phytoremediation practices or as a supplement in agricultural management to improve crop resilience in polluted environments. Further research could explore the molecular mechanisms underlying GA’s protective effects and its potential synergy with other biostimulants to enhance heavy metal tolerance in a broader range of crops.

The overlooked salt: Impact of dark septate endophytes on alfalfa at varying sodium sulfate levels

Sodium sulfate (Na2SO4) is one sodium salt extensively found in saline soils; in certain regions, it is the dominant salt present. Dark septate endophytes (DSE) are competent in enhancing plants’ resistance to stressed environments. Nevertheless, little is known about the role of DSE in enhancing plant tolerance to Na2SO4. This study examined DSE growth and its impacts on alfalfa plants exposed to varying Na2SO4 concentrations (0%, 0.15%, 0.3%, and 0.45% (w/w)). Our findings revealed that DSE can thrive even in salt-stress environments. On the 8th day of cultivation, their biomass reached the highest level under 0.45% salt concentration. Moreover, DSE successfully colonized alfalfa roots and significantly enhanced plant growth and development across the various salt gradients. Notably, DSE made the highest contribution 68% to the total biomass of alfalfa at 0.45% salt concentration. Meanwhile, DSE significantly decreased the presence of root’s Na+ across varying salt gradients. Additionally, DSE significantly increased catalase (CAT) activity at salt concentrations of 0.3% and 0.45%. Our study also revealed strong positive correlations of plant biomass with the root index, root’s K+ content, and K+/Na+ ratio, and strong negative correlations of plant biomass with root’s Na+ content and soil’s Na+ and SO42− contents. Structural equation modeling (SEM) demonstrated that DSE indirectly enhanced plant’s shoot biomass under various salt stresses via increasing root length, decreasing root’s Na+ content, and raising CAT activity, while salt indirectly reduced plant’s shoot weight via reducing root length or increasing root’s Na+ content or exerted a direct negative effect on plant shoot biomass. Thus, DSE are instrumental in bolstering the salt tolerance of plants, which holds strategic importance for the management of saline-alkali soils.

Proline Accumulation and Drought Tolerance in Green Gram (Vigna radiata L.)

Green gram (Vigna radiata L.), a key legume crop in Asia, contributes to sustainable agriculture by fixing atmospheric nitrogen and providing valuable nutrients. Despite its importance, productivity is hindered by various factors including drought, affecting key physiological and biochemical processes, leading to reduced yields. This study aimed to identify drought-tolerant green gram genotypes by evaluating 50 accessions for root, shoot and biochemical parameters under controlled moisture stress. An increase in root length and diameter under stress was observed, which aids in nutrient uptake and osmoregulation. Conversely, shoot length and dry weight decreased due to moisture limitations, with genotypes like VBN 3 and PLM 38 showing resilience by maintaining higher dry weights. Biochemical analysis revealed that proline accumulation, which correlates positively with drought tolerance, increased in most genotypes, particularly in IC 395518 and ML 1415. This suggests its role in maintaining cell turgor and mitigating stress effects. Chlorophyll content decreased under stress, while total phenolic content increased in some genotypes, further indicating drought tolerance. Correlation and path analysis revealed strong positive relationships between root traits and proline content, emphasizing their importance in drought tolerance. The study concludes that genotypes with robust root systems and higher proline accumulation are more capable of withstanding drought, highlighting the need for breeding programs targeting these traits for improved green gram productivity under changing climates.

Inoculation with Azospirillum brasilense as a Strategy to Reduce Nitrogen Fertilization in Cultivating Purple Maize (Zea mays L.) in the Inter-Andean Valleys of Peru.

Purple maize has gained global significance due to its numerous nutraceutical benefits. However, sustaining its production typically requires high doses of nitrogen fertilizers, which, when applied in excess, can contaminate vital resources such as soil and water. Inoculation with nitrogen-fixing microorganisms, such as those from the Azospirillum genus, has emerged as an alternative to partially or fully replace nitrogen fertilizers. This study aimed to evaluate the inoculation effect with A. brasilense and varying nitrogen fertilization levels on the yield and quality of purple maize. The experiment was carried out using a randomized complete block design (RCBD) with a 2 × 5 factorial arrangement and five replications. Treatments comprised two inoculation levels (control without inoculation and inoculation with A. brasilense) under five nitrogen doses (0, 30, 60, 90, and 120 kg∙ha-1, applied as urea). Inoculation with A. brasilense resulted in a 10.5% increase in plant height, a 16.7% increase in root length, a 21.3% increase in aboveground fresh biomass, a 30.1% increase in root fresh biomass, and a 27.7% increase in leaf nitrogen concentration compared to the non-inoculated control. Regarding yield, the inoculated plants surpassed the control in both purple maize yield (kg∙ha-1) and cob weight by 21.8% and 11.6%, respectively. Across all fertilization levels and parameters assessed, the inoculated treatments outperformed the control. Furthermore, for parameters, namely plant height, leaf nitrogen content, and cob dimensions (length, diameter, and weight), the A. brasilense inoculation treatment with 90 kg N∙ha-1 was statistically equivalent or superior to the non-inoculated control with 120 kg N∙ha-1. These results indicate that inoculation with A. brasilense positively impacted purple maize at all nitrogen levels tested and improved nitrogen use efficiency, enabling a reduction of 30 kg N∙ha-1 without compromising performance in key parameters.

Bio-prospecting fluoride tolerant bacteria for their optimistic contribution in instigating resilience against fluoride stress in Oryza sativa L.

In recent years, the effects of fluoride (F) pollution in numerous ecosystems such as groundwater, soil, etc. Have become a major issue worldwide. This increase in F pollution is a direct consequence of the unbridled use of fertilizers in agricultural and several other human activities that require immediate and appropriate action. Therefore, this manuscript reveals important findings on the efficacy of bacteria isolated from agricultural fields in central Chhattisgarh in manifesting resistance to F and in reversing the F-induced oxidative damage in susceptible Oryza sativa L, (Var. MTU1010). Chronic exposure of Oryza sativa L. to sodium fluoride (NaF) (50 mg L−1) severely impeded growth and various physiological parameters such as germination percentage, biomass and root and shoot length and stimulated the formation of reactive oxygen species (ROS), which enhanced electrolyte leakage and formation of cytotoxic products like malondialdehyde. To this end, potential bacterial strains, namely MT2A, MT3A, MT4A, and Du3A were isolated, screened for various plant growth promoting (PGP) traits and used to explore their efficiency to mitigate F toxicity in Oryza sativa L. in vivo. The seedlings inoculated with the bacterial strains showed significant development as evidenced by an increase in root and shoot length, biomass and chlorophyll content. Additionally, inoculation of these strains in combination with F stress significantly decreased oxidative stress by increasing the expression of protective genes encoding antioxidant enzymes and boosted agronomic traits remarkably. Overall, the manuscript demonstrates the pivotal role played by the isolated bacteria in abating ill effects of F in the Oryza sativa L. seedlings and proves their potential as protective bioagents against F stress.

Metabolic pathways regulated by strigolactones foliar spraying enhance osmoregulation and antioxidant defense in drought-prone soybean

BackgroundDrought stress is a significant abiotic stressor that hinders growth, development, and crop yield in soybeans. Strigolactones (SLs) positively regulate plant resistance to drought stress. However, the impact of foliar application of SLs having different concentrations on soybean growth and metabolic pathways related to osmoregulation remains unknown. Therefore, to clarify the impact of SLs on soybean root growth and cellular osmoregulation under drought stress, we initially identified optimal concentrations and assessed key leaf and root indices. Furthermore, we conducted transcriptomic and metabolic analyses to identify differential metabolites and up-regulated genes.ResultsThe results demonstrated that drought stress had a significant impact on soybean biomass, root length, root surface area, water content and photosynthetic parameters. However, when SLs were applied through foliar application at appropriate concentrations, the accumulation of ABA and soluble protein increased, which enhanced drought tolerance of soybean seedlings by regulating osmotic balance, protecting membrane integrity, photosynthesis and activating ROS scavenging system. This also led to an increase in soybean root length, lateral root number and root surface area. Furthermore, the effects of different concentrations of SLs on soybean leaves and roots were found to be time-sensitive. However, the application of 0.5 µM SLs had the greatest beneficial impact on soybean growth and root morphogenesis under drought stress. A total of 368 differential metabolites were screened in drought and drought plus SLs treatments. The up-regulated genes were mainly involved in nitrogen compound utilization, and the down-regulated metabolic pathways were mainly involved in maintaining cellular osmoregulation and antioxidant defenses.ConclusionsSLs enhance osmoregulation in soybean plants under drought stress by regulating key metabolic pathways including Arachidonic acid metabolism, Glycerophospholipid metabolism, Linoleic acid metabolism, and Flavone and flavonol biosynthesis. This study contributes to the theoretical understanding of improving soybean adaptability and survival in response to drought stress.

Study on the synergistic effects of siderophore bacteria and arbuscular mycorrhizal fungi on the improvement of iron nutrition in Cinnamomum camphor

Iron, an essential micronutrient for plant growth, is often found in insoluble forms in alkaline soils, leading to inadequate absorption, poor plant growth, and iron deficiency chlorosis. This study explores the effects of co-inoculation with the siderophore bacteria Lysinibacillus fusiformis (S5) and Arbuscular mycorrhizal fungi (AMF) on the iron uptake and growth of Cinnamomum camphora seedlings. The experiment included four treatment groups: a control with plain water, AMF only, S5 only, and a combined AMF+S5 group, over a three-month pot experiment. Compared to the control, the combined AMF+S5 treatment significantly enhanced root mycorrhizal colonization and spore density by 15.6% and 31.8%, respectively. Additionally, there were increases in stem thickness, plant height, and root length by 34.7%, 15.6%, and 80.3%, respectively. In terms of photosynthetic physiology, the combined treatment improved the net photosynthetic rate and stomatal conductance by 37.5% and 46.7%, respectively, while reducing intercellular CO2 concentration by 8.7%. Furthermore, total iron content in Cinnamomum camphora increased by 11%, and root-available iron content (FCR) by 26.6%. These results demonstrate that co-inoculation with AMF and siderophore bacteria significantly promotes growth and iron absorption in seedlings, effectively mitigating symptoms of iron deficiency chlorosis, providing a scientific basis for developing efficient microbial co-inoculation techniques.

The effect of pinching and leaf defoliation on plant root architecture and bulb characteristics in lilium

In plants, leaves are the most important organs together with roots in terms of plant development. The effects of leaf defoliation and pinching on root architecture and bulb development were determined in lilies 'Vong' cultivar. For this purpose, leaf defoliation was determined as 0, 25%, 50%, 100%, and pinching was performed. Root length (cm), root surface area (cm2), root volume (cm3), root diameter (mm), number of tips, number of forks, and number of crossings in root architecture were measured. The effect of bulb properties was also determined in main bulb diameter (mm), bulb fresh weight (g), bulb dry weight (g), and bulbil diameter (mm). Leaf defoliation was found to affect root growth negatively. As the defoliation rate increased, the root architectural features decreased compared to the control. In contrast to leaf defoliation, the pinching application significantly increased root length (7568 cm), root surface area (9254 cm2), root volume (176 cm3), number of tips (8553), number of forks (40106), and number of crossings (7950). However, it had no effect on root diameter in two applications. In addition, while leaf defoliation decreased bulb characteristics, pinching application significantly increased bulb fresh weight (54.24 g), bulb dry weight (4.43 g), and bulb diameter (19.43 mm). It was also determined that the application that reduced the bulb fresh weight, bulb dry weight and bulb diameter the most was 100% leaf defoliation. As a result, it was found that pinching is the best method to ensure healthy root growth and bulb development, suggesting that it can be recommended for growing lilium bulbs.

La (NO3)3 substantially fortified Glycyrrhiza uralensis’s resilience against salt stress by interconnected pathways

The taproot of Glycyrrhiza uralensis is globally appreciated for its medicinal and commercial value and is one of the most popular medicinal plants. With the decline of wild G. uralensis resources, cultivated G. uralensis has become a key method to ensure supply. However, soil salinization poses challenges to G. uralensis cultivation and affects the yield and quality of it. In this study, the inhibitory effects of NaCl and Na2SO4 on yield and quality of G. uralensis were comprehensively evaluated in a three-year large-scale pot experiment, and the alleviating effects of supplementation with lanthanum nitrate (La (NO3)3) on G. uralensis were further evaluated under salt stress. The findings indicate that La (NO3)3 significantly strengthened the plant's salt tolerance by enhancing photosynthetic capacity, osmolyte accumulation, antioxidant defenses, and cellular balance of ions, which led to a substantial increase in root biomass and accumulation of major medicinal components. In comparison to the NaCl-stress treatment, the 0.75 M La (NO3)3 + NaCl treatment resulted in a 20% and 34% increase in taproot length and biomass, respectively, alongside a 52% and 43% rise in glycyrrhizic acid and glycyrrhizin content, respectively. Similar improvements were observed with 0.75 M La (NO3)3 + Na2SO4 treatment, which increased root length and biomass by 14% and 26%, respectively, and glycyrrhizic acid and glycyrrhizin content by 40% and 38%, respectively. The combined showed that application of La (NO3)3 not only significantly improved the salt resilience of G. uralensis, but also had a more pronounced alleviation of growth inhibition induced by NaCl compared to Na2SO4 stress except in the gas exchange parameters and root growth. This study provides a scientific basis for high-yield and high-quality cultivation of G. uralensis in saline soils and a new approach for other medicinal plants to improve their salt tolerance.Graphical

Optimizing nitrogen fertilizer for improved root growth, nitrogen utilization, and yield of cotton under mulched drip irrigation in southern Xinjiang, China

The root system plays a crucial role in water and nutrient absorption, making it a significant factor affected by nitrogen (N) availability in the soil. However, the intricate dynamics and distribution patterns of cotton (Gossypium hirsutum L.) root density and N nutrient under varying N supplies in Southern Xinjiang, China, have not been thoroughly understood. A two-year experiment (2021 and 2022) was conducted to determine the effects of five N rates (0, 150, 225, 300, and 450 kg N ha−1) on the root system, shoot growth, N uptake and distribution, and cotton yield. Compared to the N0 treatment (0 kg N ha−1), the application of N fertilizer at a rate of 300 kg N ha−1 resulted in consistent and higher seed cotton yields of 5875 kg ha−1 and 6815 kg ha−1 in 2021 and 2022, respectively. This N fertilization also led to a significant improvement in dry matter weight and N uptake by 32.4% and 53.7%, respectively. Furthermore, applying N fertilizer at a rate of 225 kg N ha−1 significantly increased root length density (RLD), root surface density (RSD), and root volume density (RVD) by 49.6–113.3%, 29.1–95.1%, and 42.2–64.4%, respectively, compared to the treatment without N fertilization (0 kg N ha−1). Notably, the roots in the 0–20 cm soil layers exhibited a stronger response to N fertilization compared to the roots distributed in the 20–40 cm soil layers. The root morphology parameters (RLD, RSD, and RVD) at specific soil depths (0–10 cm in the seedling stage, 10–25 cm in the bud stage, and 20–40 cm in the peak boll stage) were significantly associated with N uptake and seed cotton yield. Optimizing nitrogen fertilizer supply within the range of 225–300 kg N ha−1 can enhance root foraging, thereby promoting the interaction between roots and shoots and ultimately improving cotton production in arid areas.