Root Research Articles

Changes in the potato rhizosphere microbiota richness and diversity occur in a growth stage-dependent manner

Plant root and soil-associated microbiomes are influenced by niches, including bulk and rhizosphere soil. In this work, we collected bulk and rhizosphere soil samples at four potato developmental stages (leaf growth, flowering, tuber elongation and harvest) to identify whether rhizosphere microbiota are structured in a growth stage-dependent manner. The bacterial and fungal microbiota showed significant temporal differences in the rhizosphere and bulk soil. Rhizobacteria were most diverse at the tuber elongation stage, and dominant ASVs identified as Sphingomonas, Rhodanobacter, Sphingobium, Hyphomicrobium, and Solirubrobacter spp. In contrast, rhizosphere fungal diversity peaked at flowering stage, with Lecanicillium spp. being prominent. Furthermore, the abundance of saprophytic fungal genera, including Colletotrichum and Fusarium, and Alternaria, sharply increased at harvest stage, likely contributing to plant residue decomposition. Indicator taxa analysis highlighted the dominance of these genera at harvest. Network analysis revealed increased microbial complexity during the later growth stage, with 721 edges compared to 521 edges in the early growth stage. This increase included positive correlations between bacteria and negative correlations between bacteria and fungi. These changes suggest that microbial interactions become more interconnected and complex as potato plants mature. Our findings highlight the potential role of saprophytic fungi in shaping microbial dynamics during the later growth stage in rhizosphere soil.

Effectiveness of Plant-Induced Resistance Against Root-Knot Nematode Depends on the Policy of Using Inducer on the Host Plant.

This research was conducted to determine the relationship between plant defense responses and the extent of treatment applied to either the aerial parts or roots of the plant. The experimental treatments included different methods of application (spraying versus soil drenching), varying treatment areas (one-sixth, one-third, half, or all of the plant's aerial parts and roots) with SA, and infecting the plants with root-knot nematodes. Evaluation of plant growth and nematode pathogenicity indices in the greenhouse section, H2O2 accumulation rate, and phenylalanine ammonia lyase enzyme activity (in aerial parts and roots) were carried out in biochemical experiments. The results showed that treating less than one-third of the aerial parts with salicylic acid (SA) did not significantly impact plant growth or nematode pathogenicity indices. However, it did lead to a notable increase in hydrogen peroxide (H2O2) accumulation, while phenylalanine ammonia lyase (PAL) enzyme activity remained unchanged. In contrast, treating more than one-third of the aerial parts resulted in decreased nematode pathogenicity and enhanced production of defense compounds. Notably, treatments targeting the roots consistently demonstrated a more pronounced effect on nematode suppression and increased defense compound levels, emphasizing the importance of root treatment, as this is where nematodes are primarily present. Overall, the study highlights the differential impact of treatment location and extent on plant defense mechanisms and suggests that strategic targeting of either aerial or root tissues can optimize plant responses against nematode attacks.

Phytophthora alni Infection Reinforces the Defense Reactions in Alnus glutinosa - Frankia Roots to the Detriment of Nodules.

Alnus glutinosa, able to establish symbiosis with mutualistic bacteria of the genus Frankia, is one of the main species in European riparian environments, where it performs numerous biological and socio-economic functions. However, riparian ecosystems face a growing threat from Phytophthora alni, a highly aggressive waterborne pathogen causing severe dieback in A. glutinosa. To date, the tripartite interaction between the host plant, the symbiont Frankia and the pathogen remains unexplored but is critical for understanding how pathogen-induced stress influences the nodule molecular machinery and so on the host-symbiont metabolism. In the present study, we aimed to explore for the first time how P. alni affects the overall molecular processes of Alnus glutinosa - Frankia nodules, with a special focus on unraveling the spatial expression of defense mechanisms within these tissues. We conducted a laboratory experiment based on P. alni infection of young A. glutinosa seedlings nodulated with Frankia alni ACN14a, non-infected or infected with the pathogen P. alni. Multi-omics analyses were carried out on nodules (N) and associated roots (AR) of the same plant in order to underline the impact on the nodule molecular processes (i.e. N/AR markers) when the host plant is infected compared to non-infected plants. Our results revealed that P. alni infection modified the molecular nodule processes and induced reprograming of defense-related markers by a shift in associated roots to the detriment of nodules. These findings suggest that A. glutinosa reinforces locally its immune responses in roots but moderates this activation in nodule to preserve its Frankia symbiont.

Increasing Productivity and Recovering Nutritional, Organoleptic, and Nutraceutical Qualities of Major Vegetable Crops for Better Dietetics

The intensive use of chemical fertilizers for vegetable cultivation to achieve higher productivity causes soil degradation, resulting in an alarming decline (25–50%) in nutritional quality and a reduction in a wide variety of nutritionally essential minerals and nutraceutical compounds in high-yielding vegetable crops over the last few decades. To restore the physio-chemical and biological qualities of soil as well as the nutritional and nutraceutical qualities of fresh produce, there is a growing desire to investigate the remedial impacts of organic sources of nutrition. This study specifically focused on the impact of six different ratios of chemical fertilizers and organic sources with microbial inoculation on vegetable productivity, nutrition quality, and soil health parameters. Results show that replacing chemical fertilizers with organic sources in the presence of a microbial consortium supports the proliferation of the microbial population in the soil rhizosphere and improves the nutritional status and physico-chemical quality of soil, which is the area around the roots of plants where maximum nutrient uptake occurs. This combination of factors significantly recovers overall soil quality, increasing crop productivity by 13.58 to 18.32 percent in tomato, brinjal, and okra. Experimental findings likewise indicate that an assortment of organic sources with a microbial consortium significantly recovers the abundance of beneficial microbes and earthworms in the rhizosphere, which leads to an improvement in nutritional, organoleptic, and nutraceutical quality, with higher antioxidant contents in all three vegetables grown in arid climate conditions.

Arbuscular mycorrhizal colonization defines root ecological strategies in an extreme arid environment

The symbiosis between mycorrhizae fungi and plant roots is essential for plant establishment in nearly all terrestrial ecosystems. However, the role of mycorrhizal colonization (colM) in shaping root ecological strategies remains poorly understood. Emerging research identifies colM as a key trait influencing the multidimensional covariation of root traits within the Root Economic Space (RES), where a ‘collaboration gradient’ is proposed. At one end of this gradient, species with larger root diameters (RD) rely on colM for resource acquisition through an ‘outsourcing’ strategy, while at the other end, species with finer roots and greater exploration capacity employ a ‘do it yourself’ strategy to acquire resources independently. Although the RES framework has improved our understanding of root strategies, the relationship between colM and root traits in desert ecosystems remains underexplored, particularly in hyper-arid environments, where limited resources can constrain both plant and mycorrhizal survival. In this study, we examine the root ecological strategies of 32 dominant shrub species in Chile’s Coastal Atacama Desert, focusing on the link between specific root traits and colM. We found that larger RD correlated with higher levels of colM, supporting the ‘outsourcing’ strategy within the ‘collaboration gradient’ hypothesis of the RES. Additionally, RD and colM emerged as playing key roles in defining both dimensions of root ecological strategies. Moreover, we identified colM as a central hub trait in the root phenotypic network, underscoring its role in survival strategies under hyper-arid conditions. These findings emphasize the critical importance of colM in modulating plant ecological strategies and highlight the need to further investigate how AM enhances root lifespan and optimizes resource uptake in extreme environments.

Determination of optimal gamma radiation dose for mutation breeding in 'Sabz' fig (Ficus carica L.) cuttings based on radiosensitivity and phenotypic changes.

The dried fig cv. Sabz of Iran, distinguishes out among the several fig cultivars for its unique characteristics and excellent properties. The aims to this study were 1) Carefully monitoring the resulting phenotypic changes in growth patterns, leaf morphology, shoot traits, root characteristics, and other relevant traits after irradiated with different gamma rays; 2) Investigating the LD25, 50, 75 and GR25, 50, 75 values at different gamma radiation doses for chose optimum dose. According to our results, the LD50 was 70 Gy, while the LD25 and LD75 were approximately 48 and 95 Gy, respectively. Data analysis revealed that higher doses, ranging from 50 to 90 Gy, led to a reduction in leaf area for fig hardwood cuttings compared to those exposed to lower doses of gamma irradiation (10, 20, 30, and 40 Gy). In fig cuttings, the plant height gradually decreased in line with increasing irradiation doses up to 60 Gy. Among the root traits, root number was particularly influenced by higher radiation doses. On other hand, when fig cuttings were exposed to a 40 Gy radiation dosage, the average root count dropped by 50%. However, when fig cuttings were subjected to a 90 Gy radiation dose, the average root count surged by 90.7% in comparison to the control treatment. Additionally, the GR50 values were 63 Gy for internode length, 67 Gy for leaf area and 56 Gy for plant height and aerial biomass. However, the GR50 values for root number, root volume, and root biomass were 46 Gy, 57 Gy, and 51 Gy, respectively. An analysis based on the GR25, GR50, and GR75 values indicated that plant height, aerial biomass and root biomass exhibited greater sensitivity to radioactivity in comparison to other plant portions of the fig. According to the biological responses in the 'Sabz' fig, 60 Gy of gamma radiation is a suitable dose for initial mutagenesis studies.

Identifying a Biocontrol Bacterium with Disease-Prevention Potential and Employing It as a Powerful Biocontrol Agent Against Fusarium oxysporum

Biocontrol microbes are environment friendly and safe for humans and animals. To seek biocontrol microbes effective in suppressing Fusarium oxysporum is important for tomato production. F. oxysporum is a soil-borne pathogen capable of causing wilt in numerous plant species. Therefore, we found a biocontrol bacterium with an excellent control effect from the rhizosphere soil of plant roots. In this work, we focus on two parts of work. The first part is the identification and genomic analysis of the biocontrol bacterium Y-4; the second part is the control efficiency of strain Y-4 on F. oxysporum. For this study, we identified strain Y-4 as Bacillus velezensis. It is an aerobic Gram-positive bacterium that can secrete a variety of extracellular enzymes and siderophores. Strain Y-4 also contains a large number of disease-resistant genes and a gene cluster that forms antibacterial substances. In addition, we found that it significantly inhibited the reproduction of F. oxysporum in a culture dish. In the indoor control effect test, after treatment with strain Y-4 suspension, the disease index of tomato plants decreased significantly. Furthermore, the control efficiency of the plants was 71.88%. At the same time, Y-4 bacterial suspension induced an increase in POD and SOD enzyme activities in tomato leaves, resulting in increased plant resistance. Taken together, strain Y-4 proves to be an effective means of controlling F. oxysporum in tomatoes.

Visualizing the Spatial Distribution of Metabolites in Angelica sinensis Roots by Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Imaging.

Angelica sinensis is one of the most popular traditional Chinese medicines (TCM) and has been extensively used to treat various diseases. Hundreds of endogenous ingredients have been isolated and identified from this herb, but their spatial distribution within the plant root is largely unknown. In this study, we tried to investigate and map within-tissue spatial distribution of metabolites in Angelica sinensis roots. After optimization of experiment conditions, the 1,5-diaminonaphthalene (1,5-DAN) was chosen as the matrix and was sprayed on the surface of root sections. Then matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) was employed to perform insitu detection and obtain detail spatial distribution information of metabolites in Angelica sinensis roots. The spatial distributions of a wide range of metabolites including organic acids, amino acids, oligosaccharides, and phospholipids were characterized and visualized in Angelica sinensis roots. Majority of these metabolites were located in the phloem and xylem, while ferulic acid was mainly present in the cork layer. The results revealed a dramatic metabolic heterogeneity among different regions of the roots and distinct spatial distribution patterns of different metabolites. Additionally, the metabolic pathways involved in the biosynthesis of choline were also successfully localized and visualized. This study comprehensively characterized the spatial distribution of metabolites in Angelica sinensis roots, which would prompt the understanding of its chemical separation, biosynthesis, and pharmacological activities.

Development of a qPCR assay for early detection and quantification of Phytopythium vexans in kiwifruit plant and soil affected by Vine Decline Syndrome.

Kiwifruit Vine Decline Syndrome (KVDS) is a soilborne disease affecting Actinidia fruit trees in perennial cropping systems. Since its emergence in 2012, studies have increasingly identified the oomycete Phytopythium vexans as a major causative agent of the disease. P. vexans is also implicated in complex soilborne disease systems of woody perennial crops, including replant disease in apple and pear. To date, most molecular assays for the detection of P. vexans target the nuclear ribosomal internal transcribed spacer (ITS), a region which is ill-suited for distinguishing between closely related oomycete species. The cytochrome oxidase subunit I (COI) mitochondrial gene was targeted for the design of new primers because it was previously identified as a better marker for differentiating oomycete species. The FOR2/REV4RCA primer pair gave the best results regarding PCR specificity and was selected for use in a SYBR Green-based qPCR assay. The specificity of the qPCR assay was evaluated using 29 P. vexans strains (including different phylogenetic groups) as well as a wide variety of closely related off-target species associated with pathogenic soil communities of fruit trees. P. vexans strains were successfully quantified down to 20 fg in water and in DNA extracted from kiwifruit roots. P. vexans was also detected in artificially inoculated Actinidia plant roots as well as in a variety of naturally infected field samples of both kiwi and apple trees. These results suggest that the qPCR assay developed in this study is highly sensitive and specific to target pathogen, regardless of sample matrix.

Exogenous Oxygen Replenished as a Promising Method for Mitigating Salt Stress in Maize Seedling Stage

ABSTRACT Soil salinization is one of the main reasons for soil degradation, which limiting the improvement of soil productivity. To evaluate the response plant height, stem diameter, plant biomass and nutrient uptake of maize, and soil properties to various salt stress and oxygen supply rates, a soil culture experiment with two factors were carried out: different salt stress degrees (A0, 0 g L−1 NaCl irrigation; A3, 3 g L−1 NaCl irrigation; A6, 6 g L−1 NaCl irrigation; A9, 9 g L−1 NaCl irrigation;) and different rhizosphere oxygen supply degrees (B0, 0 ml L−1 H2O2 solution; B0.5, 0.5 ml L−1 H2O2 solution; B1, 1 ml L−1 H2O2 solution; B1.5, 1.5 ml L−1 H2O2 solution). The results showed that the plant height, stem diameter, aboveground and root biomass of maize under different salt stress degrees were reduced by 6.8–9.8%, 4.4–9.8%, 18.4–45.5% and 21.4–35.8% at the end of the experiment compared to A0, respectively. Meanwhile, the nutrient uptake of aboveground and root were declined, especially under high salt stress degree, but the sodium (Na+) uptake was increased significantly. Rhizosphere oxygen supply enhanced the plant height, stem diameter, aboveground and root biomass by 2.0–6.5%, 4.1–6.1%, 27.5–56.6% and 19.5–47.1% at the end of the experiment compared to B0, respectively. The restriction of nutrient absorption caused by salt stress could be alleviated. Soil quality indicators were influenced by salt stress and oxygen supply management as well. Overall, rhizosphere oxygen supply could alleviate the restriction of salinization on maize growth at seedling stage, improve soil chemical quality and water use efficiency.

Styrofoams Bunched by Plant Roots in Coastal Environments

Styrofoams Bunched by Plant Roots in Coastal Environments

Root Development of Tomato Plants Infected by the Cacao Pathogen Moniliophthora perniciosa Is Affected by Limited Sugar Availability.

Moniliophthora perniciosa is the causal agent of the witches' broom disease of cacao (Theobroma cacao), and it can infect the tomato (Solanum lycopersicum) 'Micro-Tom' (MT) cultivar. Typical symptoms of infection are stem swelling and axillary shoot outgrowth, whereas reduction in root biomass is another side effect. Using infected MT, we investigated whether impaired root growth derives from hormonal imbalance or sink competition. Intense stem swelling coincided with a reduction in root biomass, predominantly affecting lateral roots. RNA-seq analyses of root samples identified only a few differentially expressed genes involved in hormone metabolism, and root hormone levels were not expressively altered. Inoculation of the auxin highly-sensitive entire mutant genotype maintained the impaired root phenotype; in contrast, the low-cytokinin MT transgenic line overexpressing CYTOKININ OXIDASE-2 (35S::AtCKX2) with fewer symptoms did not exhibit root growth impairment. Genes involved in cell wall, carbohydrate, and amino acid metabolism were downregulated, accompanied by lower levels of carbohydrate and amino acid in roots, suggesting a reduction in metabolite availability. 13CO2 was supplied to MT plants, and less 13C was detected in the roots of infected MT but not in those of 35S::AtCKX2 line plants, suggesting that cytokinin-mediated sugar sink establishment at the infection site may contribute to impaired root growth. Exogenous sucrose application to roots of infected MT plants partially restored root growth. We propose that the impairment of lateral root development is likely attributed to disrupted sugar signalling and photoassimilate supply by establishing a strong sugar sink at the infected stem.

Phosphorus Fertilization and Chemical Root Pruning: Effects on Root Traits During the Nursery Stage in Two Mediterranean Species from Central Chile

The role of a plant root system in resource acquisition is relevant to confront drought events caused by climate change. Accordingly, nursery practices like phosphorous (P) fertilization and root pruning have been shown to modify root architecture; however, their combined benefits require further investigation in Mediterranean species. We evaluated the effect of applied P concentrations (0, 15, 60, and 120 mg L−1 P) with or without chemical (copper) root pruning (WCu, WoCu, respectively) in Aristotelia chilensis and Quillaja saponaria on morpho-physiological and root architecture traits. Higher P concentration increased nutrient content in both species concurrent with higher growth. In A. chilensis, higher P concentrations only increased the length and volume of medium roots. In Q. saponaria, P additions increased root length and diameter and the length and volume of fine and medium roots. The root-to-shoot ratio declined with WCu in A. chilensis (23.1%) and Q. saponaria (15.7%). Unlike our hypothesis, fine root architecture remained unaffected with root pruning in A. chilensis, while fine root length and volume decreased with increasing P concentrations in Q. saponaria. Thus, P fertilization enhances root development more consistently than root pruning, highlighting the need for further testing under water deficit conditions to optimize nursery practices.

Role of Arbuscular Mycorrhizal Fungi in Maintaining Sustainable Agroecosystems

Arbuscular mycorrhizal (AM) fungi play a crucial role in maintaining sustainable agroecosystems by forming mutualistic relationships with plant roots, improving soil health, facilitating nutrient uptake, and enhancing resilience to abiotic stresses. The mutualistic relationship between AM fungi and plants promotes a balanced microbial community and improves soil structure by forming stable soil aggregates. Additionally, AM fungi can lower the adverse effects of high soil phosphorus (P) while also enhancing plant tolerance to drought, salinity, and heavy metal toxicity through osmotic regulation and antioxidant production. Arbuscular mycorrhizal fungi also support beneficial microorganisms, such as potassium (K)-solubilizing microbes and nitrogen (N)-transforming bacteria, which enhance the nutrient dynamics in soil. However, intensive agricultural practices, including heavy tillage and continuous monoculture, disrupt AM fungal networks and reduce microbial diversity, impairing their effectiveness. Adopting conservation practices such as reduced tillage, crop rotation, and organic amendments supports AM fungal growth. Incorporating mycorrhizal crops and utilizing native fungal inoculants can enhance AM fungal colonization and plant growth. These strategies collectively bolster soil health, crop productivity, and resilience, offering a promising solution to the environmental and agricultural challenges posed by intensive farming. By promoting AM fungi growth and colonization, agroecosystems can achieve long-term productivity and increased sustainability.

Super-resolution expansion microscopy in plant roots.

Super-resolution methods provide far better spatial resolution than the optical diffraction limit of about half the wavelength of light (∼200-300 nm). Nevertheless, they have yet to attain widespread use in plants, largely due to plants' challenging optical properties. Expansion microscopy improves effective resolution by isotropically increasing the physical distances between sample structures while preserving relative spatial arrangements and clearing the sample. However, its application to plants has been hindered by the rigid, mechanically cohesive structure of plant tissues. Here, we report on whole-mount expansion microscopy of thale cress (Arabidopsis thaliana) root tissues (PlantEx), achieving a four-fold resolution increase over conventional microscopy. Our results highlight the microtubule cytoskeleton organization and interaction between molecularly defined cellular constituents. Combining PlantEx with stimulated emission depletion (STED) microscopy, we increase nanoscale resolution and visualize the complex organization of subcellular organelles from intact tissues by example of the densely packed COPI-coated vesicles associated with the Golgi apparatus and put these into a cellular structural context. Our results show that expansion microscopy can be applied to increase effective imaging resolution in Arabidopsis root specimens.

Plant Adaptation and Soil Shear Strength: Unraveling the Drought Legacy in Amorpha fruticosa

Climate change has led to an increasing frequency of droughts, potentially undermining soil stability. In such a changing environment, the shallow reinforcement effect of plant roots often fails to meet expectations. This study aims to explore whether this is associated with the alteration of plant traits as a response to environmental change. Focusing on Amorpha fruticosa, a species known for its robust root system that plays a crucial role in soil consolidation and slope stabilization, thereby reducing soil and water erosion, we simulated a drought-rewetting event to assess the legacy effects of drought on the soil shear strength and the mechanical and hydrological traits associated with the reinforcement provided by A. fruticosa. The results show that the legacy effect of drought significantly diminishes the soil shear strength. Pretreated with drought, plant roots undergo morphological alterations such as deeper growth, yet the underground root biomass and diameter decline, thereby influencing mechanical reinforcement. Chemical composition analysis indicates that the plant’s adaptation to drought modifies the intrinsic properties of the roots, with varying impacts on different root types and overall reinforcement. Concurrently, the stomatal conductance and transpiration rate of leaves decrease, weakening the capacity to augment soil matric suction through transpiration and potentially reducing hydrological reinforcement. Although rewetting treatments aid in recovery, drought legacy effects persist and impact plant functional attributes. This study emphasizes that, beyond soil matric suction, plant adaptive mechanisms in response to environmental changes may also contribute significantly to reduced soil shear strength. Consequently, ecological restoration strategies should consider plant trait adaptations to drought, enhancing root systems for soil conservation and climate resilience.

Bacterial wilt disease alters the structure and function of fungal communities around plant roots

BackgroundFungal communities around plant roots play crucial roles in maintaining plant health. Nonetheless, the responses of fungal communities to bacterial wilt disease remain poorly understood. Here, the structure and function of fungal communities across four consecutive compartments (bulk soil, rhizosphere, rhizoplane and root endosphere) were investigated under the influence of bacterial wilt disease.ResultsThe results showed that bacterial wilt disease caused different assembly patterns of fungal communities in the bulk soil, rhizosphere, rhizoplane and endosphere. Under the influence of bacterial wilt disease, a decreased fungal diversity was observed in the rhizoplane and endosphere, and completely different kinds of fungal genera were enriched in the four compartments. The complexity and stability of fungal networks were less affected, but the number of key fungal members in networks were significantly reduced in diseased samples. Functional predictions based on FUNGuild suggested that with the pathogen infection, saprotrophic fungi were increased in the bulk soil, but pathotrophic fungi (potential plant and animal pathogens) were increased in the rhizosphere, rhizoplane and endosphere.ConclusionThis work provides a deep insight into the effects of bacterial wilt disease on fungal communities along the soil-root continuum, and is helpful to identify plant-associated beneficial fungi to resist plant disease.Clinical trial numberNot applicable.

Aeroponics: Transforming Vegetable Farming for the Future

The global population is projected to reach 9.8 billion by 2050, necessitating a 60-70% increase in agricultural production. Traditional soil-based farming faces challenges like soil degradation, water scarcity and climate vulnerability. Aeroponics, a soil-less cultivation method, offers a solution. By suspending plant roots and misting them with nutrient-rich solutions, aeroponics maximizes resource efficiency, reduces water consumption by 96% and ensures consistent yields year-round. It's particularly effective for high-value crops like potatoes and tomatoes. Despite initial costs and technical complexities, aeroponics presents a sustainable alternative for future food production, demonstrated by successful implementations worldwide, including in India and the United States.

Foliar application of nitrates limits lead uptake by Cucumis sativus L. plants.

Lead is a toxic heavy metal, which accumulates in the soil and is readily absorbed by plant roots. The uptake of toxic elements by crops is a serious threat to human health. For this reason, it is important to prevent the incorporation of heavy metals into the food chain. Our previous study showed that foliar application of calcium nitrate reduces the intensity of lead uptake by different plant species. A significant decrease in metal concentration was observed both in the roots and in the shoots of three crops: tomato, cucumber, and flax. The present research investigated the mechanism for limiting lead accumulation in plant tissues. The experiments were conducted on Cucumis sativus L. seedlings, grown in hydroponic conditions. To compare the role of Ca2 + and NO3- ions in the restriction of lead uptake three different calcium salts (nitrate, chloride, and formate), and two nitrates (calcium and potassium) were applied foliarly to plants. The results show that Ca(NO3)2 is more efficient in decreasing lead accumulation in tissues than other calcium salts which suggests an important role of NO3- ions in the process. In addition, the study demonstrated that the exogenous supply of nitrates helps compensate for nitrogen deficiency caused by lead action and supports the mineral balance. The reduction in lead toxicity to plants after foliar application of nitrates may be due to the stimulation of the biosynthesis of nitric oxide - a key molecule responsible for stress response.

Hybrid Pennisetum colonization by Bacillus megaterium BM18-2 labeled with green fluorescent protein (GFP) under Cd stress

Researchers have reported that Bacillus megaterium BM18-2 reduces Cd toxicity in Hybrid Pennisetum, but understanding the interaction between plants and associated endophytes is crucial for understanding phytoremediation strategies under heavy metal stress. The current study aims to monitor the colonization patterns of GFP-labeled endophytic bacteria BM18-2 on Hybrid Pennisetum grass. Additionally, it will monitor Cd’s effect on plant bacterial colonization. Confocal laser scanning microscopy of plant roots infected with gfp tagged BM18-2 revealed that the bacterium colonised root hairs and epidermal cells at the early stage of colonization, and over time, the bacteria penetrated to the internal tissues following their colonization of the stem and leaf. The roots, stems, and leaves of H. Pennisetum grown in Cd-contaminated soil contained a higher number of bacteria than those grown in normal soil. The result of Cd translocation indicated the condensation of heavy metals in the root cells and stem, while no Cd was found in the leaf. The study will also look for the enzymatic activity of bacteria BM18-2 and use Leadmium Green AM dye to track how Cd is taken up and moved through the plant. The enzymatic activity results showed that BM18-2 can produce catalase and amylase, but did not record any cellulase or lipase activity. As a result, the pattern of useful endophytic BM18-2 colonization through H. Pennisetum grass will aid in the application and maintenance of these bacteria in farming, and it presents new opportunities for the development of innovative strategies in the fields of agriculture and biotechnology.