Root Growth Research Articles

The role of OsRGA1 in aerenchyma formation and adventitious root growth in rice seedlings based on the U-Gompertz model

BackgroundAerenchyma in adventitious roots plays a crucial role in rice growth under flooding conditions. However, the mechanisms underlying the dynamic formation process of aerenchyma remain poorly understood, largely due to the time-consuming and labor-intensive nature of traditional sectioning methods for analyzing aerenchyma formation. In this study, we optimized the Gompertz model to investigate the dynamic process of aerenchyma formation and its relationship with root growth. The materials used included the wild-type Nipponbare (NIP) as well as OsRGA1 knockout and overexpression lines, rga1–5 and RGA1–OE1.ResultsAll three parameters of the optimized U-Gompertz model directly characterized the dynamic process of aerenchyma formation. Compared to NIP, the rga1–5 knockout line exhibited significantly lower maximum value and rate of aerenchyma formation, with delays at the initial point, maximum acceleration point, inflection point, maximum deceleration point, and maximum value point. In contrast, RGA1–OE1 line displayed an opposite trend. Additionally, OsRGA1 upregulated RBOH gene expression, reduced catalase and peroxidase activities, and consequently increased the endogenous H2O2 content from the initial point to the inflection point of aerenchyma formation.ConclusionsAs evidenced by the optimized U-Gompertz model, our results demonstrate that OsRGA1 accelerates aerenchyma formation by increasing H2O2 levels, thereby enhancing root activity and promoting root growth in rice.

Role of Plant Growth Promoting Rhizobacteria for Advanced Sustainable Agricultural Practices: A Review

The role of PGPR in nutrient cycling, soil structure improvement, and soil pH modification. Traditional agriculture relies heavily on chemical inputs, which pose significant threats to the environment and deplete natural resources. The environmental challenges posed by chemical-based agriculture and emphasize the urgent need for sustainable alternatives in the face of climate change. Plant Growth-Promoting Rhizobacteria (PGPR) are beneficial soil microorganisms that enhance plant growth through various direct and indirect mechanisms, offering a sustainable approach to improving soil fertility and crop productivity. PGPR have emerged as a sustainable alternative, fostering plant development, and enhancing stress resilience. A comprehensive understanding of the underlying signalling pathways and stress management mechanisms is essential to maximizing their potential. Plant health has been demonstrated, nutrient uptake has improved, and environmental stress has been reduced with the help of PGPR. PGPR facilitate nitrogen fixation, phosphorus and potassium solubilization, and organic matter decomposition, enhancing nutrient availability and promoting plant growth. Their ability to produce exopolysaccharides contributes to soil aggregation, improving soil structure and water retention. Additionally, PGPR modifies rhizosphere pH, enhancing nutrient solubility and availability. PGPR also promote crop yield by enhancing root and shoot growth, improving seed germination, and increasing stress tolerance against drought, salinity, and heavy metal contamination. PGPR provides effective biocontrol against pathogens through antibiosis, competition, and induced systemic resistance (ISR), contributing to improved crop resilience. Despite their potential, several challenges hinder the widespread adoption of PGPR, including inconsistent field performance, limited shelf-life, compatibility issues with native soil microbiota, and regulatory barriers. Emerging approaches such as genetic engineering, multi-strain consortia, and nano-formulations are being developed to enhance PGPR efficacy and stability under diverse environmental conditions. Integrating PGPR with organic and chemical fertilizers presents a promising strategy for achieving higher yields while minimizing environmental impact. Research should focus on understanding PGPR-plant signalling pathways, optimizing formulation techniques, and developing policies to promote their commercial use. Collaborative efforts between researchers, industries, and policymakers are essential to enhance the application of PGPR in sustainable agriculture. Widespread adoption of PGPR-based technologies could significantly contribute to global food security, environmental sustainability, and the reduction of chemical inputs in agriculture. The potential of PGPR as a valuable tool for enhancing agricultural productivity through environmentally friendly practices. Future research should focus on developing efficient, cost-effective formulations and enhancing collaboration between researchers, policymakers, and industries to ensure global food security and environmental sustainability.

First Record of Cyst Nematode (Heterodera filipjevi) on Wheat in Shaanxi Province of China.

The cyst nematode pathogens can cause a yield loss of 30-50% via stunting root growth on grains (Bonfil et al. 2004). Heterodera avenae, H. filipjevi, and H. latipons are identified as the most economically influential and harmful species on wheat (Toumi et al. 2016). H. filipjevi was first detected in Henan Province in 2010, and had subsequently spread to many provinces (Peng et al. 2010; Peng et al. 2016; Cui et al. 2021). In May 2022, wheat plants showing yellowing and premature senescence were observed in different wheat planting areas throughout Shaanxi Province. Nine soil samples were collected from Pucheng County (34°94'32"N, 109°57'23"E) of Shaanxi Province. Among them, six soil samples were detected to have cysts via the sieving-decanting method with an average cyst population density of 10.6 cysts per 100 cubic centimeters of soil. The cysts and second-stage juveniles (J2s) were identified based on both morphological and molecular identification. Morphologically, the cysts are lemon shaped, with a protruding vulval cone. The shell surface had a Z-shaped pattern and covered with a white subgrain layer. The cone of the vulva is bifenestrate in horseshoe-shape. Underbridge exists and is well-developed. The measurements of the cysts (n=16) as follows: body length 670.24 ± 60.67 (593.43 to 778.42) μm; body width 479.03 ± 54.51 (355.91 to 567.52) μm; length/width ratio 1.41 ± 0.16 (1.20 to 1.72); fenestra length 52.30 ± 4.32 (46.82 to 59.13) μm; fenestra width 27.59 ± 3.39 (22.42 to 34.91) μm; vulval slit length 9.17 ± 0.47 (8.69 to 10.37) μm. J2s measurements (n=15) as follow: body length 522.46 ± 24.18 (482.54 to 572.23) μm; body width 26.47 ± 3.08 (22.21 to 30.16) μm; stylet length 23.42 ± 3.24 (16.48 to 29.11) μm. These morphological characteristics and morphometrics are consistent with those of H. filipjevi (Peng et al. 2010). The DNA of single cyst was extracted with four replicates (Shao et al. 2022). The COI fragment sequence was amplified with the specific primers (HfF9/HafR8) according to Niu's research (Niu et al. 2016). The identities of amplification fragments (Genbank PQ650771, PQ650772 and PQ650773) are 98.77%, 99.08% and 98.77% matching the published sequences of H. filipjevi (MG523031.1 and MK093059.1), respectively. We also used the RAPD species-specific primers of H. filipjevi (HfF1/HfR1) to acquire 647bp sequences (Genbank PV165784, PV165785 and PV165786) which have 99.54%, 99.38% and 99.38%identities with published H. filipjevi sequence (KC529338.1) (Peng et al. 2013). Pathogenicity was confirmed by infecting wheat (Triticum aestivum 'Weilong 169'). The eggs of the cyst nematode population hatched at 15℃, and the emerged J2s were used for potted wheat inoculating in greenhouse under 18-24℃. Nine plants in three pots were inoculated and three plants in one pot remained served as the uninoculated control, the inoculum was 800 J2s per pot. After three months, an average of 15.7 cysts were detected from each of the inoculated plants, and the cysts were identified as H. filipjevi via molecular characteristics. To our knowledge, this is the first report of H. filipjevi in shaanxi. As Shaanxi is an important part of the Huang-Huai-Hai wheat region in China, where its occurrence should be attached great importance.

Multigenerational toxicity effects and impact of antibiotics exposed to duckweed, Lemna minor.

The escalating presence of antibiotics in aquatic ecosystems poses substantial risks to public health and ecosystem stability. The objective of this study was to examine the effects of three common antibiotics-ciprofloxacin (CIP), erythromycin (ERY), and sulfamethoxazole (SMX)-on the growth and physiology of Lemna minor (L. minor) across three generations (parental (F0), first filial (F1), and second filial (F2)). Specifically, the research aimed to determine how these antibiotics influence frond number, frond area, root area, and photosynthetic pigment content in L. minor. Higher concentrations of CIP (50μg/L, 250μg/L, and 1250μg/L) significantly decreased frond numbers (F2>F1>F0), while ERY exhibited the opposite trend, and SMX displayed adaptation in F2. ERY increased frond area at a lower concentration (10μg/L), while high concentrations of CIP (250μg/L and 1250μg/L) and lower concentrations of SMX (10μg/L and 50μg/L) reduced it. CIP displayed a biphasic response on root growth, with 10μg/L decreasing root area by 760μm2 and 50μg/L and 1250μg/L, increasing it by 2480μm2 and 2300μm2, respectively. ERY consistently inhibited root growth. The F1 generation showed the most pronounced reduction in green area, particularly under higher CIP concentrations (1250μg/L). Chlorophyll A (Chl A) and carotenoid contents were resilient to antibiotic stress, while Chlorophyll B (Chl B) exhibited generation-specific responses. This study highlights the need for continued monitoring of antibiotics in aquatic systems and calls for further research on the long-term impacts of antibiotics on aquatic plants and ecosystems.

Biocontrol and plant growth-promoting activities of airborne bacteria.

The potential of airborne bacteria as a sustainable alternative for agriculture was evaluated. Bacteria were isolated from air samples and evaluated for their plant growth-promoting (PGPB) and antifungal properties as biocontrol of phytopathogens. Results showed that diverse bacterial species, including Exiguobacterium, Rhodococcus, Kocuria, and Staphylococcus genera, exhibited PGPB activities such as phosphorus solubilization, siderophore production, and auxin production. Kocuria strains showed high auxin production. Rhodococcus sp. was observed to significantly promote root growth and the formation of beneficial biofilms on bean roots. Additionally, this bacterium opened the xylem vessels, facilitating the absorption of nutrients and water. Kocuria sp. strains exhibited high antifungal activity against Fusarium oxysporum and Phytophthora cinnamomi due to volatile organic compounds (VOCs) produced by these strains. Volatile profile revealed compounds such as dimethyl disulfide, pyrazines, and benzaldehyde derivatives associated with fungal growth inhibition. This study demonstrates the potential of airborne bacteria as both biofertilizers (producers of indole-3-acetic acid IAA, potassium, and phosphorus solubilizers, siderophore producers, and ammonium producers) and biocontrol agents (against the phytopathogenic fungus Fusarium oxysporum and Phytophthora cinnamomi).

Humic acids modify root architecture in Arabidopsis through H+-ATPase-dependent target of rapamycin activation in concert with Ca2+ and ROS signaling

BackgroundHumic acids (HA) function as plant biostimulants, enhancing plant metabolism by activating the primary proton transport system, which promotes root growth. This study investigated the effects of HA on root growth, H+ extrusion, Ca2+ signaling, and reactive oxygen species (ROS) production, examining how HA might integrate nutrient sensing with growth regulation through plant hormone transport.ResultsHA rapidly increased cytosolic Ca2+ and ROS, and altered root architecture in Arabidopsis lines Columbia-0 (Col-0) and G548 TOROE (overexpressing TARGET OF RAPAMYCIN). In Col-0, HA exposure increased total, primary, and lateral root lengths, while in TOROE plants, only primary root length changed. HA also doubled the expression of transcripts in Col-0 roots, including those for PM H+-ATPase (AHA2), TOR kinase, ROS-related RBOHC, and auxin transporters LAX3 and PIN3. Only AHA2 and RBOHC were upregulated in TOROE plants. Findings indicate that HA promotes rhizosphere acidification and plasma membrane potential regulation via AHA2 and RBOHC, linked to auxin transporters and calcium signaling.ConclusionsThe data suggest HA, rich in compounds like quinones and flavonoids, stimulates root development by triggering Ca2+ waves, NADPH oxidase and H+-ATPase activities. These findings advance our understanding of TOR and H+-ATPase roles in root architecture.Graphical abstract

Impact of Erosion-Induced Topsoil Dilution on Rapeseed Root Growth, Assimilate C Input, and Turnover in the Soil

Impact of Erosion-Induced Topsoil Dilution on Rapeseed Root Growth, Assimilate C Input, and Turnover in the Soil

Evaluation of urea loaded nano clay biopolymer composites and nitrification inhibitors on nitrogen use efficiency under maize-wheat cropping system

Across the globe, cereal crops have only < 30% nitrogen (N) use efficiency (NUE) due to significant loss of N.During previous decade nitrification inhibitors (NI) were promoted for better N management and utilization. However, recentresearch had been focused on developing nanoclay polymer composite based (NCPC)slow-release fertilizer for better nutrient delivery and efficient use.This study aims to synthesize a novel nano clay biopolymer composite (NCBPC) product to replace conventional fertilizers to enhance NUE. Nanoclay biopolymer composite was synthesized using different polymers such as acrylic acid and maize flour as a starch source at a 20% replacement level with acrylamide monomers via free radical polymerization and N,N,-methylene bisacrylamide as crosslinkers, nano-bentonite as diffusion barrier and ammonium persulfate as initiator. The concentration of nitrification inhibitors (DCD and 4-Fluoro-3-nitrobenzaldehyde, Schiff bases) was 1% and 3% of the N dose. Fourier transform infrared (FTIR) spectra, X-ray diffraction (XRD) and scanning electron microscope (SEM) were employed for characterization of NCBPCs and a laboratory incubation study conducted to monitor N release pattern. Field evaluation of prepared product carried out in randomized complete block design (RCBD) with three replications in maize and wheat crops. The recommended amount of N was 150 kg ha−1and applied at the rates of 0, 50, 75, and 100% by using urea and NCBPC (loaded with urea and nitrification inhibitors) in the three equal split doses at 45, 60, and 90 DAS (days after sowing). Our results highlightthat, NCBPC loaded with 75%N + NI maintains higher ammoniacal N and lower nitrate N in soil leaching studies and promotes better or comparable leaf chlorophyll content, root growth (length, volume and surface area), grain and straw yield as obtained under 100% N through conventional prilled urea fertilization in both the crops. NCBPC loaded with 75% N and 3% dicyandiamide (DCD) (T3) emerged as the best combination inboth the crops. It had greater apparent N recovery (40.43% and 40.60%) and agronomic NUE (36.20% and 37.10%) than conventional fertilizer in both crops, respectively. Therefore, combined application of NCBPC loaded with urea and NIs offer 25% cutdown of total N requirement and same time may be focused for better yield and N use efficiency in maize and wheat crops.

Influence of coloured shade nets on shoot and root growth of dragon fruit stem cuttings

Influence of coloured shade nets on shoot and root growth of dragon fruit stem cuttings

Improving ectomycorrhizal colonization and morpho-physiological traits of Pinus cooperi seedlings through organic nitrogen fertilization.

Mycorrhizal associations play a crucial role in afforestation efforts, as they enhance the acquisition of nutrients and water, thereby supporting seedling establishment. However, the influence of nitrogen (N) forms in the soil, particularly the organic N, on the formation of mycorrhizal associations and their subsequent effects on seedling morpho-physiology remains poorly understood. In this study, we examine the mycorrhizal colonization, along with morpho-physiological and functional traits, in Pinus cooperi seedlings following fertilization with organic N in controlled nursery conditions. A factorial experiment was performed with Pinus cooperi C. E. Blanco seedlings using two N sources: organic N (amino acids) and inorganic N (NH4NO3) and two N doses: low and high (60 vs 200 mg N seedling-1). Seedlings were inoculated with a mixture of native fungi, but the phylogenetic analysis showed that Suillus placidus (Bonord.) Singer was the only species colonizing roots. Organic N promoted similar morphology and nutritional status as inorganic N, though at a low N rate, it improved root growth and mycorrhizal colonization. High N fertilization improved seedling growth and nutritional status but reduced mycorrhizal colonization. Mycorrhizal colonization improved needle P concentration, delayed plant desiccation, and reduced root cellular damage when seedlings were subjected to desiccation, though it decreased plant growth and needle N concentration. We conclude that organic N fertilization improves mycorrhization of P. cooperi with S. placidus, but the fertilization dose should be adjusted to meet species-specific requirements in order to optimize plant quality and promote afforestation success.

Foot traffic on turf primarily shaped the endophytic bacteriome of the soil-rhizosphere-root continuum

Foot traffic on turf can cause grass wear-stress and soil compaction, adversely impacting turf health. The root microbiome, consisting of diverse microbes, plays a crucial role in enhancing plant resilience to abiotic stressors. However, the effects of foot traffic on these microbes and the mechanisms they employ to help plant survival remain largely unknown. Here, we investigated how foot traffic affected microbial communities of the root endosphere, rhizosphere, and bulk soil in Bermudagrass (Cynodon spp.) and Zoysiagrass (Zoysia spp.) turfs. Foot traffic was simulated to mimic six professional football games per week using a modified Baldree traffic simulator. High-throughput amplicon sequencing targeting 16S rRNA for bacteria and ITS for fungi was employed to analyze microbial communities. Foot traffic slightly and significantly reduced soil moisture and inorganic nitrogen, likely due to soil compaction and associated impairment on microbial activity. Microbial alpha diversity varied across microhabitats, with no discernible effect of foot traffic. However, microbial community composition was impacted by foot traffic, being more pronounced on bacteria of the root endosphere and on fungi of the bulk soil. In light of the genetic potential predicted by PICRUSt2, foot traffic enriched a few pathways of the endophytic bacteriome, including nitrifier denitrification (PWY7084) and mannosylglycerate biosynthesis (PWY5656). This indicated that root endophytes could help turfgrass to tolerate foot traffic via controls on the concentration of nitric oxide, the signaling molecule for root growth, and mannosylglycerate, the compatible solute for protecting enzymes against osmotic stress. Foot traffic also enhanced degradation pathways of carbohydrates and 4-coumarate, the constituent of turfgrass cell walls (PWY-3801, PWY-2221, PWY-7046), indicating the faster turnover of root tissues. Along the root-rhizosphere-bulk soil continuum, the bacteriome varied substantially in composition and also exhibited contrasting genetic potentials from stress alleviation to nutrient supply in coping with grass growth. But foot traffic had little effect on the genetic potential of bacteriome in rhizosphere and bulk soil. Our findings indicated that the endophytic bacteriome was more sensitive to foot traffic than the bacteriome in the rhizosphere and bulk soil and could potentially help turf survival via influences on plant signal molecules and compatible solutes.

Plant growth regulators from the liquid culture of Lepista sordida.

"Fairy rings" are zones that stimulate or inhibit grass growth, caused by interactions between a fungus and a grass. Lepista sordida is one of the fairy ring-forming fungi. (1S,2S)-1-(4-Chloro-3-methoxyphenyl)propane-1,2-diol (1) along with ten compounds (2-11) were isolated from the culture broth and mycelia of L. sordida. The structures were identified by spectroscopic data analyses, and this was the first reported isolation of 1 from a natural source. The plant growth regulatory activity of 3-6 was investigated using bentgrass seedlings. Compound 3 promoted root growth at 0.1 μmol/paper, while inhibited it at 1 μmol/paper. Compound 4 inhibited root growth at 0.1 and 1 μmol/paper. Compound 6 significantly promoted shoot growth at 1 μmol/paper.

The Microbiome of Continuous Wheat Rotations: Minor Shifts in Bacterial and Archaeal Communities but a Source for Functionally Active Plant-Beneficial Bacteria

Continuous wheat cropping often leads to yield decline, with suspected causes including increased pathogen susceptibility, decreased root growth, or low nutrient use efficiency, although the exact causes remain unknown. Here, we investigated soil and root-associated bacterial and archaeal communities in wheat under rotation versus continuous cultivation, monitored fungal pathogen presence, and used beneficial bacteria to mitigate Gaeumannomyces tritici (Ggt) disease symptoms in greenhouse experiments. Sampling was conducted at two field sites with different soil textures over 2 years and at two plant developmental stages, capturing site-specific and seasonal fluctuations. By cultivation, 767 bacterial isolates were screened for plant-beneficial traits. Amplicon sequencing revealed minor effects on community structure due to wheat rotational position but pronounced effects related to site, year, and microhabitat. Rhizoplane isolates with plant-beneficial traits were mainly Flavobacterium, Microbacterium, Pedobacter, Pseudomonas, Stenotrophomonas, and Variovorax. Continuous wheat rotations showed the highest proportion of bacteria with fungal antagonistic potential, indicating plant roots’ recruitment of beneficial bacteria. Introducing Ggt in the greenhouse experiment altered the bacterial and archaeal community, confirming field study results and demonstrating that applying beneficial bacteria early in the season at the seedling stage can control Ggt and improve plant growth. This study highlights the dynamic nature of wheat's belowground bacterial and archaeal community, influenced by soil type, season, and microhabitat, with wheat rotation playing a minor role. In addition, it confirms the potential of selected Bacillus and Pseudomonas isolates, whether used individually or in consortia, for microbe-assisted mitigation of yield decline in intensive wheat production. [Formula: see text] Copyright © 2025 The Author(s). This is an open access article distributed under the CC BY 4.0 International license .

Research Progress on the Effect of Biochar Addition on Soil Microorganisms in Cultived Land

Biochar is a carbon-rich product derived from the pyrolysis of fibrous biomass. It has attracted considerate attention because of its functions, such as improving soil fertility, achieving soil carbon sequestration, and adsorbing soil pollutants. Soil microorganisms are the main components of the soil life system in cultivated land, playing an important role in soil structure, nutrition, ecological balance, and plant health. Soil microorganisms are involved in the complex relationship between biochar addition and cultivated soil and plants. Therefore, the direct effects of biochar on soil microorganisms and indirect effects on soil properties, plant root growth, and metabolic status were investigated. Biochar could directly provide habitat and nutrients for soil microorganisms, alter enzymatic activity, and affect signal communication. Polycyclic aromatic hydrocarbons （PAHs） and other substances in biochar were not conducive to the survival and metabolism of soil microorganisms. Biochar could indirectly affect soil microorganisms by improving soil physical and chemical properties, such as porosity, pH, aggregate structure, and bulk density, stimulating plant growth, changing secretion status, and enrichment of harmful substances. The observed effects of biochar on the metabolic activities and community structure of soil microorganisms in cultivated land were complex, related to the properties of biochar raw materials, processing technology, and application rate. We proposed biochar products with low preparation cost, few potential hazards, and high comprehensive benefits and prospected future research directions, providing a basis for the study of biochar regulation in cultivated land soil.

Morpho-biochemical Changes of Chili (Capsicum annuum L) Genotypes under Different Salt Stress Conditions

Salinity is a devastating abiotic stress worldwide; seriously hamper crop production through altering growth and biochemical constituents of plants at the coastal ecosystem. Growing salt tolerant genotypes is the most effective strategy to improve crop production in the ecosystem. Objective of the experiment was to investigate the saline induced changes in growth and biochemical constituents of different chili genotypes, and identify salt tolerant chili genotype. The study evaluated three chili genotypes—Anal 1701, Black Kobra, and Traditional variety—grown under varying salinity levels (0, 3, 6, 9, and 12 dSm-1 at the germination stage; and 0, 3, and 6 dSm-1 at the vegetative stage) using a two-factorial completely randomized design with three replications during Rabi season of 2024. Salinity stress had a significant impact on plant height, proline, and chlorophyll content during the vegetative stage (P &lt; 0.001). Anal 1701 showed the greatest proline concentration (38.54 mg 100 g⁻¹ fresh leaf) and chlorophyll-a content (4.75 mg g-1 fresh leaf). Traditional variety and Black Kobra came in second and third, respectively; while Black Kobra showed lowest chlorophyll-a concentration (1.05 mg g-1 fresh leaf). During germination stage up to 6 dSm-1 salinity level the root and shoot growth was increased; thereafter increasing salt concentration drastically reduced the parameters. The germination and vegetative stage experiment suggested that the Anal 1701 chili cultivar be cultivated in the soils influenced by coastal salt with an alternative of traditional variety. The study's conclusions will help to choose chili genotypes for upcoming breeding initiatives that try to increase salinity tolerance and reduce production loss. J Bangladesh Agril Univ 23(1): 33–41, 2025

A Bletilla striata calcium-dependent protein kinase gene, BsCDPK1, enhances salinity stress tolerance in Arabidopsis thaliana

Calcium signaling plays a crucial role in stress sensing and alleviation in plants, with calcium-dependent protein kinases (CDPKs) acting as major sensors of Ca2+ flux. This study examined the function of BsCDPK1, a CDPK from the endangered medicinal orchid Bletilla striata, in mediating salt stress responses, a significant constraint on plant growth and productivity. Expression of the BsCDPK1 gene was upregulated by salt stress and abscisic acid (ABA). Transgenic plants expressing BsCDPK1 displayed salt insensitivity, as evidenced by seed germination, cotyledon greening, and relative root growth under high-salt conditions. Constitutive expression of BsCDPK1 in Arabidopsis upregulated AtMYB2 and the stress-response gene AtDREB2A. These findings highlight BsCDPK1’s role in the plant salt stress response, which is significant for conserving Bletilla striata understanding the plant calcium signaling mechanism, and potentially enhancing crop salt tolerance.

Coating Seeds with Paenibacillus polymyxa ZF129 Microcapsule Suspension Enhanced Control Effect on Fusarium Root Rot and Promoted Seedling Growth in Cucumber

Fusarium root rot, a destructive soil-borne fungal disease, necessitates eco-friendly biocontrol strategies. This study developed a microbial seed-coating approach using the antagonistic strain Paenibacillus polymyxa ZF129, formulated into a microencapsulated powder (10⁸ CFU/g) and a suspension (CS-ZF129). CS-ZF129 application enhanced cucumber resistance, achieving 46.30 ± 0.02% disease suppression while promoting root growth. The maximum increase in the fresh weight of the root in the promotion of rectangular growth was 47.16%. The colonization dynamics of ZF129 in the rhizosphere were systematically tracked, revealing its antagonistic correlation with Fusarium proliferation. An enzymatic activity analysis further uncovered the underlying regulatory mechanisms, demonstrating induced defense responses through pathogenesis-related protein activation. These findings highlight ZF129’s dual functionality as a biocontrol agent and a plant growth promoter, offering a sustainable strategy against soil-borne pathogens.

Effects of Freeze-Thaw Cycles on Uptake Preferences of Plants for Nutrient: A Review.

Freeze-thawing is an abiotic climatic force prevalent at mid-to-high latitudes or high altitudes, significantly impacting ecosystem nitrogen (N) and phosphorus (P) cycling, which is receiving increasing attention due to ongoing global warming. The N and P nutrients are essential for plant growth and development, and the uptake and utilization of these nutrients by plants are closely linked to external environmental conditions. Additionally, the availability of N and P nutrients influences the ecological adaptability of plants. Adapting plants to diverse external environments for the efficient uptake and utilization of N and P nutrients represents a main focus in contemporary ecological research on plant nutrient utilization in the ecosystems of mid-to-high latitudes or high altitudes. Through a comprehensive analysis of the experimental results regarding plant nutrient uptake and utilization in mid-to-high-latitude or high-altitude ecosystems, this paper discussed the processes of soil N and P cycling and the different utilization strategies of nutrient forms employed by plants during freezing and thawing. Freeze-thaw cycles affect the availability of N and P in the soil. Under freeze-thaw conditions, plants preferentially take up readily available N sources (e.g., nitrate (NO3--N) or ammonium (NH4+-N)) and adjust their root growth and timing of N uptake, developing specific physiological and biochemical adaptations to meet their growth needs. When nutrient conditions are poor or N sources are limited, plants may rely more on low-molecular-weight organic nitrogen (e.g., amino acids) as N sources. Plants adapt to changes in their environment by adjusting root growth, making changes in root secretions, and utilizing microbial communities associated with the P cycle to support more efficient P utilization. Future research should (i) enhance the monitoring of plant roots and nutrient dynamics in the subterranean layers of the soil; (ii) incorporate a broader range of nutrients; (iii) examine specific freeze-thaw landscape types, along with the spatial and temporal heterogeneity of climate change within seasons, which is essential for minimizing uncertainty in our understanding of plant nutrient utilization strategies.

Soil texture modifies the impact of microplastics on winter wheat growth

Abstract Purpose Research on the impact of microplastics (MPs) on plant performance has primarily focused on MP type or concentration, often neglecting the role of soil texture. Methods In this study, a 42-day experiment was conducted in which winter wheat was grown in three soils of different textures, contaminated with two types of MPs: low-density polyethylene particles (LDPE) and polyester fibers (PES) at 0.4% concentration. The effects on soil water content, nutrient levels, and plant growth were examined. Results In silty loam, LDPE reduced root length and biomass, likely due to altered soil texture, which created more macropores and reduced water and nutrient availability. PES fibers had similar effects, indicating that changes in soil porosity impacted root access to resources. In sandy loam, both MP types reduced root growth, with PES fibers causing a significant 85% reduction in root length and decreasing nitrogen content, suggesting impaired nutrient availability due to reduced nitrification. Conversely, in silty clay loam, LDPE increased root length by 4.6 times, likely due to enhanced water movement pathways, although it also increased water loss. PES fibers showed minimal positive effects on root growth but reduced nutrient content. Conclusion Overall, soil texture had a significant impact on how MP affected plant growth, as the two types of MP had different effects on different soil textures. LDPE increased macroporosity in fine soils, promoting root growth, but reduced nutrient uptake in coarse soils. PES fibers influenced soil structure, affecting water retention and nutrient availability differently in different soil types. The study highlights the complexity of MP–soil–plant interactions. Moreover, it also calls attention to rethinking soil management in the future, such as using biodegradable alternatives, applying biochar or avoiding plastic-coated controlled-release fertilizers.

Evaluating the Phytohormone Proficiencies of Multifarious Bacillus rugosus for Growth Promotion in Arachis hypogaea (L.).

The application of Plant Growth-Promoting Rhizobacteria (PGPR) in agriculture is increasingly emphasized as a sustainable alternative to hazardous agrochemicals. This study aimed to isolate and characterize PGPR strains from the rhizospheric soil of Arachis hypogaea L., hypothesizing that the rhizosphere of a healthy plant harbors beneficial microbes with significant plant growth-promoting (PGP) attributes. The isolate AB1 demonstrated promising PGP traits, including phosphate solubilization (56.44 µg mL⁻¹), zinc solubilization (6.1 µg mL⁻¹), ammonia production (3.8 µM µg mL⁻¹), and the synthesis of hydrogen cyanide (HCN) and phytohormones. Objectives included identifying these traits and evaluating their impact on the growth of Arachis hypogaea L. Phytohormonal profiling of AB1 through Gas Chromatography-Mass Spectrometry (GC-MS) and Fourier Transform Infrared Spectroscopy (FTIR) confirmed indole fractions with characteristic peaks at 3338 cm⁻¹ (N-H stretching), 1641 cm⁻¹ (C-N bond of the indole ring), and 2984 cm⁻¹ (C-H aromatic stretching). Cytokinins and gibberellins were also detected. Molecular, physiological, and biochemical analyses identified the isolate as Bacillus rugosus AB1, with gene sequences deposited under GenBank accession number MZ373174. The present study is the first report of Bacillus rugosus AB1 as a PGPR, showcasing multifaceted PGP traits that significantly enhanced root and shoot growth, biomass, and chlorophyll content in Arachis hypogaea L., demonstrating its potential as a biofertilizer for sustainable agriculture.