Influence of biosynthesized magnesium oxide nanoparticles on growth and physiological aspects of cowpea (Vigna unguiculata L.) plant, cowpea beetle, and cytotoxicity.

Recently, agricultural management innovation has incorporated engineered nanoparticles. The current investigation was carried out to produce magnesium oxide nanoparticles (MgONPs) for the first time applying S. cerevisiae extract. FTIR, XRD, HRTEM, and zeta potential analysis were used to characterize the MgONPs. The FTIR data show that the bioactive substances reduce and cap the synthesized MgONPs. The crystalline metallic MgONPs had four significant peaks in the XRD pattern. The size and form of MgONPs were validated by TEM, which exhibited spherical structures with an average size of 27 nm. The effect of various dosages of MgONPs administered to the cowpea (Vigna unguiculata L.) plant on all in vitro parameters was shown to be significant in the study. The concentration 200 ppm was the most significant treatment which increased shoot length, shoot dry-weight and root dry-weight by 27.35%, 45.09%, and 31.91% when compared with the untreated cowpea plants. MgONPs significantly increased photosynthetic pigments, with 150 ppm treatment significantly increasing soluble proteins and carbohydrates. MgONPs effectively treated cowpea C. maculatus, with dose and time-dependent insecticidal activity. MgONPs death rates varied by 82.66% and 100% on fifth day. Biochemical and histopathological studies of rats were investigated. Rats treated with MgONPs showed higher GOT, GPT, Urea levels, but lower creatinine, indicating significant differences. MgONPs-treated rats' liver showed mild to moderate histopathologic changes, including portal blood vessel congestion, lymphocytic cholangitis, and degenerative changes. MgONPs has the potential to improve cowpea development outcomes and suppress grain insects (C. maculatus).

Biocontrol of early blight disease of eggplant using endophytic Aspergillus terreus: improving plant immunological, physiological and antifungal activities.

BACKGROUND: The eggplant suffers from many biotic stresses that cause severe damage to crop production. One of the most destructive eggplant pathogens is Alternaria solani, which causes early blight disease. A pot experiment was conducted to evaluate the role of fungal endophytes in protecting eggplant against early blight as well as in improving its growth performance. RESULTS: Endophytic Aspergillus terreus was isolated from Ocimum basilicum leaves and identified morphologically and genetically. In vitro, crude extract of endophytic A. terreus exhibited promising antifungal activity against A. solani where minimum inhibitory concentration (MIC) was 1.25 mg/ml. Severity of the disease and rate of protection from the disease were recorded. Vegetative growth indices, physiological resistance signs (photosynthetic pigments, carbohydrates, proteins, phenols, proline, malondialdehyde (MDA), antioxidant enzymes), and isozymes were estimated. Alternaria solani caused a highly disease severity (87.5%) and a noticeable decreasing in growth characteristics and photosynthetic pigments except for carotenoids. Also, infection with A. solani caused significant decreases in the contents of carbohydrate and protein by 29.94% and 10.52%, respectively. Infection with A. solani caused enhancement in phenolics (77.21%), free proline (30.56%), malondialdehyde (30.26%), superoxide dismutase (SOD) (125.47%), catalase (CAT) (125.93%), peroxidase (POD) (25.07%) and polyphenol oxidase (PPO) (125.37%) compared to healthy plants. In contrast, the use of A. terreus on infected plants succeeded in recovering eggplants from the disease, as the disease severity was recorded (caused protection by 66.67%). Application of A. terreus either on healthy or infected eggplants showed several responses in number and density of peroxidase (POD) and polyphenol oxidase (PPO) isozymes. CONCLUSION: It is necessary for us to address the remarkable improvement in the photosynthetic pigments, protein, carbohydrates, and enzymatic activity compared to infected control, which opens the way for more studies on the use of biocides as safe alternatives against fungal diseases.

Grain-Priming with L-Arginine Improves the Growth Performance of Wheat (Triticum aestivum L.) Plants under Drought Stress.

Drought is the main limiting abiotic environmental stress worldwide. Water scarcity restricts the growth, development, and productivity of crops. Wheat (Triticum aestivum L.) is a fundamentally cultivated cereal crop. This study aimed to evaluate the effect of grain-priming with arginine (0.25, 0.5, and 1 mM) on growth performance and some physiological aspects of wheat plants under normal or drought-stressed conditions. Morphological growth parameters, photosynthetic pigments, soluble sugars, free amino acids, proline, total phenols, flavonoids, and proteins profiles were determined. Drought stress lowered plant growth parameters and chlorophyll a and b contents while increasing carotenoids, soluble sugars, free amino acids, proline, total phenols, and flavonoids. Soaking wheat grains with arginine (0.25, 0.5, and 1 mM) improves plant growth and mitigates the harmful effects of drought stress. The most effective treatment to alleviate the effects of drought stress on wheat plants was (1 mM) arginine, that increased root length (48.3%), leaves number (136%), shoot fresh weight (110.5%), root fresh weight (110.8%), root dry weight (107.7%), chlorophyll a (11.4%), chlorophyll b (38.7%), and carotenoids content (41.9%) compared to the corresponding control values. Arginine enhanced the synthesis of soluble sugars, proline, free amino acids, phenols, and flavonoids in wheat plants under normal or stressed conditions. Furthermore, the protein profile varies in response to drought stress and arginine pretreatments. Ultimately, pretreatment with arginine had a powerful potential to face the impacts of drought stress on wheat plants by promoting physiological and metabolic aspects.

Inoculation with Azospirillum brasilense and/or Pseudomonas geniculata reinforces flax (Linum usitatissimum) growth by improving physiological activities under saline soil conditions.

BACKGROUND: Salinized soils negatively affect plant growth, so it has become necessary to use safe and eco-friendly methods to mitigate this stress. In a completely randomized design, a pot experiment was carried out to estimate the influence of the inoculation with endophytic bacterial isolates Azospirillum brasilense, Pseudomonas geniculata and their co-inoculation on growth and metabolic aspects of flax (Linum usitatissimum) plants that already grown in salinized soil. RESULTS: The results observed that inoculation of salinity-stressed flax plants with the endophytes A. brasilense and P. geniculata (individually or in co-inoculation) increases almost growth characteristics (shoot and root lengths, fresh and dry weights as well as number of leaves). Moreover, contents of chlorophylls and carotenoids pigments, soluble sugars, proteins, free proline, total phenols, ascorbic acid, and potassium (K+) in flax plants grown in salinized soil were augmented because of the inoculation with A. brasilense and P. geniculata. Oppositely, there are significant decreases in free proline, malondialdehyde (MDA), hydrogen peroxide (H2O2), and sodium (Na+) contents. Regarding antioxidant enzymes, including superoxide dismutase (SOD), peroxidase (POD), and ascorbate peroxidase (APX), the inoculation with the tested endophytes led to significant enhancements in the activities of antioxidant enzymes in stressed flax plants. CONCLUSIONS: The results of this work showed that the use of the endophytic bacterial isolates Azospirillum brasilense, Pseudomonas geniculata (individually or in co-inoculation) could be regarded as an uncommon new model to alleviate salinity stress, especially in salinized soils.

Enhancement of Seawater Stress Tolerance in Barley by the Endophytic Fungus Aspergillus ochraceus.

Symbiotic plant-fungi interaction is a promising approach to alleviate salt stress in plants. Moreover, endophytic fungi are well known to promote the growth of various crop plants. Herein, seven fungal endophytes were screened for salt tolerance; the results revealed that Aspergillus ochraceus showed a great potentiality in terms of salt tolerance, up to 200 g L-1. The indole acetic acid (IAA) production antioxidant capacity and antifungal activity of A. ochraceus were evaluated, in vitro, under two levels of seawater stress, 15 and 30% (v/v; seawater/distilled water). The results illustrated that A. ochraceus could produce about 146 and 176 µg mL-1 IAA in 15 and 30% seawater, respectively. The yield of IAA by A. ochraceus at 30% seawater was significantly higher at all tryptophan concentrations, as compared with that at 15% seawater. Moreover, the antioxidant activity of ethyl acetate extract of A. ochraceus (1000 µg mL-1) at 15 and 30% seawater was 95.83 ± 1.25 and 98.33 ± 0.57%, respectively. Crude extracts of A. ochraceus obtained at 15 and 30% seawater exhibited significant antifungal activity against F. oxysporum, compared to distilled water. The irrigation of barley plants with seawater (15 and 30%) caused notable declines in most morphological indices, pigments, sugars, proteins, and yield characteristics, while increasing the contents of proline, malondialdehyde, and hydrogen peroxide and the activities of antioxidant enzymes. On the other hand, the application of A. ochraceus mitigated the harmful effects of seawater on the growth and physiology of barley plants. Therefore, this study suggests that the endophytic fungus A. ochraceus MT089958 could be applied as a strategy for mitigating the stress imposed by seawater irrigation in barley plants and, therefore, improving crop growth and productivity.

Efficacy Assessment of Biosynthesized Copper Oxide Nanoparticles (CuO-NPs) on Stored Grain Insects and Their Impacts on Morphological and Physiological Traits of Wheat (Triticum aestivum L.) Plant.

Herein, CuO-NPs were fabricated by harnessing metabolites of Aspergillus niger strain (G3-1) and characterized using UV-vis spectroscopy, XRD, TEM, SEM-EDX, FT-IR, and XPS. Spherical, crystallographic CuO-NPs were synthesized in sizes ranging from 14.0 to 47.4 nm, as indicated by TEM and XRD. EDX and XPS confirmed the presence of Cu and O with weight percentages of 62.96% and 22.93%, respectively, at varied bending energies. FT-IR spectra identified functional groups of metabolites that could act as reducing, capping, and stabilizing agents to the CuO-NPs. The insecticidal activity of CuO-NPs against wheat grain insects Sitophilus granarius and Rhyzopertha dominica was dose- and time-dependent. The mortality percentages due to NP treatment were 55-94.4% (S. granarius) and 70-90% (R. dominica). A botanical experiment was done in a randomized block design. Low CuO-NP concentration (50 ppm) caused significant increases in growth characteristics (shoot and root length, fresh and dry weight of shoot and root, and leaves number), photosynthetic pigments (total chlorophylls and carotenoids), and antioxidant enzymes of wheat plants. There was no significant change in carbohydrate or protein content. The use of CuO-NPs is a promising tool to control grain insects and enhance wheat growth performance.

Strategy of Salt Tolerance and Interactive Impact of Azotobacter chroococcum and/or Alcaligenes faecalis Inoculation on Canola (Brassica napus L.) Plants Grown in Saline Soil.

A pot experiment was designed and performed in a completely randomized block design (CRBD) to determine the main effect of two plant growth-promoting rhizobacteria (PGPR) and their co-inoculation on growth criteria and physio-biochemical attributes of canola plants (Brassica napus L.) plant grown in saline soil. The results showed that inoculation with two PGPR (Azotobacter chroococcum and/or Alcaligenes faecalis) energized the growth parameters and photosynthetic pigments of stressed plants. Moreover, soluble sugars' and proteins' contents were boosted due to the treatments mentioned above. Proline, malondialdehyde (MDA), and hydrogen peroxide (H2O2) contents were markedly declined. At the same time, antioxidant enzymes, viz. superoxide dismutase (SOD), ascorbate peroxidase (APX), and peroxidase (POD), were augmented due to the inoculation with Azotobacter chroococcum and/or Alcaligenes faecalis. Regarding minerals' uptake, there was a decline in sodium (Na) and an increase in nitrogen (N), potassium (K), calcium (Ca), and magnesium (Mg) uptake due to the application of either individual or co-inoculation with the mentioned bacterial isolates. This study showed that co-inoculation with Azotobacter chroococcum and Alcaligenes faecalis was the most effective treatment and could be considered a premium tool used in facing environmental problems, especially saline soils.