Crop loss brought on by phytopathogens is a significant issue that affects the entire world. Synthetic pesticides have been used for years to prevent economic losses caused by phytopathogens, raising severe worries about the environment and public health. Therefore, today, there is growing interest in using helpful microorganisms to control plant pathogens. In this way, Aspergillus chevalieri AGH-1 OP593083 and Aspergillus egyptiacus AGH-4 OP593080 isolated from wheat rhizosphere have been applied as plant growth-promoting fungi (PGPF) for combating early blight disease caused by Alternaria solani (A. solani) and inducing the defense system and growth promotional strategies in Vicia faba. Two milligrams per milliliter ethyl acetate crude extracts of A. chevalieri and A. egyptiacus demonstrated effective antifungal efficacy against A. solani with an inhibition zone of 18 and 16 mm respectively compared with 20 mm attained by fluconazole as a positive control. Moreover, the minimum inhibitory concentrations (MIC) were (0.25 and 0.5 mg/ml) for A. chevalieri and A. egyptiacus extracts respectively. Data showed that A. chevalieri was the best isolate producing indole acetic acid (IAA) and siderophores (+ + +) followed by A. egyptiacus (+ +). Also, the best isolates capable of phosphate solubilization in the soil was A. egyptiacus (+ + +), followed by A. chevalieri (+ +). It is interesting that the PGPF isolates used, whether single or mixed, showed a significant improvement in all growth and yield as well as photosynthetic pigments in Vicia faba. Moreover, A. chevalieri and A. egyptiacus played an important role in improving plant immunity by increasing phenol, proline, and antioxidant enzymes (POD and PPO) activities, as well as reducing oxidative stress by reducing MDA and H2O2. We can conclude that A. chevalieri and A. egyptiacus are considered eco-friendly safe strong inducers of Vicia faba plant immunity alternatives to chemical pesticides against A. solani early blight to preserve plant, soil, and human health.
Around the world, a variety of crops, including tomatoes, suffer serious economic losses due to the Rhizoctonia root-rot disease. Herein, Bacillus velezensis, Bacillus megaterium, and Herpaspirillum huttiense isolated from strawberry (Fragaria chiloensis var. ananassa) plants were pragmatic as plant growth promotors for battling the Rhizoctonia root rot disease and bringing about defense mechanisms as well as growth promotional strategies in tomato plants. These endophytic bacteria demonstrated potent antifungal activity against R. solani in vitro along in vivo. Data explained that the isolated endophytic bacteria could produce Indole acetic acid, Gibberellic acid GA, and siderophore as well as solubilize phosphate in the soil. The consortium of (Bacillus velezensis, Bacillus megaterium, and Herpaspirillum huttiense) increased the protection % against Rhizoctonia infection by (79.4%), followed by B. velezensis by (73.52%), H. huttiense by (70.5%), and B. megaterium by (67.64%), respectively. There was an increase in soluble proteins and carbohydrates in infected plants treated with a consortium of endophytic bacteria by 30.7% and 100.2% over untreated infected plants, respectively. Applying endophytic bacteria either alone or in combination lowered the level of malondialdehyde MDA and hydrogen peroxide H2O2 and improved the activities of antioxidant enzymes in both infected and uninfected plants. Also, bacterial endophytes have distinctive reactions regarding the number and concentrations of isozymes in both infected and uninfected plants. It could be recommended the commercial usage of a mixture of targeted bacterial endophyte strains as therapeutic nutrients against Rhizoctonia root-rot disease as well as plant growth inducer.
Trichoderma sp. is extensively applied as a beneficial fungus for the management of plant diseases, plant growth promotion, induced resistance, and plays an important role in global sustainable agriculture. This study aimed to enhance the production of microbial xylanase in high titer from the endophytic fungus Trichoderma harzianum kj831197.1, and the cloning of xylanase genes in E. coli DH5α using a pUC19 vector. A combination of glucose, 0.1 mM, Tween 80 with lactose, and 2 mM galactose combined with malt extract boostedthe enzyme production. Xylanase production was maximized at a pH of 5.0, temp. of 30 °C, and agitation of 150 rpm in the presence of malt extract and bagasse as the best nitrogen source and waste, respectively, using submerged fermentation. The molecular weight of highly purified xylanase was 32 KDa, identified using SDS-PAGE. The xylanase gene of T. harzianum kj831197.1 was screened in fungal DNA using definite primers specified in the gene bank database. The identified region was excised using restriction enzymes HindIII and EcoRI and cloned into a pUC19 plasmid vector. Optimization of fermentation conditions improved xylanase production about 23.9-fold.The antifungal efficacy of xylanase toward different phytopathogenic fungi was determined. The highest inhibition was against Corynespora cassiicola, Alternaria sp., Fusarium oxysporum, and Botrytis fabae. This study offered an economical, simple, and efficient method using Trichoderma harzianum kj831197.1 for the production of the xylanase enzyme via the submerged fermentation method.
2 February 2022 in Environmental Science and Pollution Research
Several phytopathogens attack eggplant, causing crop damage. One of the most destructive plant diseases, Root-Knot Nematode (RKN), causes significant damage to eggplant seedlings. Finding safe and effective biological alternatives to prevent eggplant root nematode disease, which significantly limits plant productivity, is the innovative aspect of this study. Six isolates of plant growth-promoting fungus (PGPF) were tested in the current work for improving biochemical defense and physio-biochemical performance in eggplant seedlings under the Meloidogyne incognita challenge. PGPF isolates were tested in vitro for some biochemical traits such as Siderophores and HCN production. Besides, the antagonistic efficacy of PGPF filtrates against M. incognita was tested in vitro. The best isolates capable of producing HCN were F5 and F3 respectively. Also, F5 followed by F3 exhibited the maximum mortality proportions of 74.20% and 60.35% mortality in nematode juveniles after 96 hours respectively. Moreover, F5 has the highest level of antioxidant activity, with IC50 145 µg/mL followed by F3 with IC50 350 µg/mL. thus, we identified F5 and F3 completely as Rhizopus microsporus (OQ291571.1 and Aspergillus oryzae OQ291572.1. Implementing R. microsporus and A. oryzae collectively in vivo study was the most successful therapy, limiting nematode recordings as 95.23%, 86.98%, 80.35%, 80%, and 68.78% reduction in females, galls, developmental stage, egg masses, second juveniles, respectively, in diseased seedlings. It could be suggested that the use of ethyl acetate extracts (EAE) of A. oryzae and R. microsporus might be commercially applied as a stimulator of eggplant and or anti-nematodes against M. incognita.
Background Silver nanoparticles (AgNPs) have fascinated extensive interest owing to their potential applications, especially in biomedicine. Materials and methods Through this investigation, AgNPs were green synthesized from AgNO3 using Nigella sativa and Piper nigrum aqueous seed extracts as a reducing agent. Biosynthesized AgNPs were characterized using transmission electron microscopy, Fourier-transform infrared spectroscopy, zeta potential, and dynamic light scattering. Antibacterial, antiviral, and anticancer activities of AgNPs were studied. Furthermore, the effect of biosynthesized AgNPs on seed germination and seedling growth of Vicia faba and Zea mays was determined. Results and conclusion Results evoked the ability of N. sativa and P. nigrum aqueous seed extracts to build up AgNPs in spherical shape with average size of 20 and 50 nm, respectively, by using transmission electron microscopy analysis. The results indicate the ability of N. sativa and P. nigrum AgNPs to inhibit both tested gram-positive and gram-negative bacteria. It is conceivable from the results that AgNPs of the N. sativa and P. nigrum are markedly effective against herpes simplex virus-1 in terms of decreased viral load and mortality, exhibiting 83.23 and 94.54% of antiviral activity, respectively. Furthermore, in-vitro studies of N. sativa and P. nigrum AgNPs against hepatocellular carcinoma have shown good cytotoxic effect, with IC50 values equal to 7.12 and 4.98 µg/ml, respectively. AgNPs exert a promoting action on seed germination percentage and seedling growth of both Vicia faba and Zea mays. This study indicated an economical, simple, and efficient ecofriendly technique using aqueous seed extracts of N. sativa and P. nigrum L. for synthesis of AgNPs and confirmed that green AgNPs are safer.