Rehab Yassin Ghareeb

Root-knot nematodes (Meloidogyne incognita) are among the most destructive pests affecting cucumber production, causing significant reductions in plant growth and yield. This study investigated the efficacy of chitosan-based soil amendments, alone and in combination with hot or cold jojoba (Simmondsia chinensis) leaf extracts and leaf powder, in suppressing nematode infestation and enhancing cucumber vegetative growth under greenhouse conditions. Treatments were evaluated for their impact on nematode reproduction, including egg masses, eggs per egg mass, second-stage juveniles (J2s), female numbers, and gall formation, as well as on plant growth parameters such as height, leaf number, and fresh and dry biomass. Chitosan alone reduced egg masses, eggs per egg mass, and J2s by 43.83%, 56.35%, and 50.63%, respectively, while hot water extract reduced them by 44.10%, 54.18%, and 50.48%. Cold extract was less effective, with reductions of 31.36%, 48.29%, and 40.31%, whereas leaf powder alone caused reductions of 44.20%, 54.60%, and 45.00%. Combined applications exhibited higher efficacy: hot extract + chitosan reduced egg masses, eggs per egg mass, and J2s by 61.64%, 59.45%, and 55.57%, leaf powder + chitosan by 64.38%, 60.70%, and 60.71%, and the triple treatment (leaf powder + chitosan + hot extract) achieved the highest suppression, reducing egg masses, eggs per egg mass, and J2s by 75.90%, 74.66%, and 69.22%, respectively. All treatments significantly enhanced cucumber growth compared with the naturally infested control. The triple treatment increased plant height by 38.5%, leaf number by 42.1%, fresh shoot biomass by 46.3%, and dry shoot biomass by 44.8%. Single treatments also improved growth, though to a lesser extent, reflecting a synergistic effect of chitosan and jojoba-derived amendments. These findings demonstrate that integrating biopolymer-based amendments with plant-derived bioactive compounds can simultaneously suppress root-knot nematode populations and promote cucumber growth. This study provides a solid basis for developing sustainable and eco-friendly integrated pest management strategies that reduce reliance on chemical nematicides.

Root-knot nematodes (RKNs) of the Meloidogyne genus impact various plants, including crops, fruits, and vegetables. Few chemical control options exist globally, and many nematicides are banned due to health and environmental risks. This study tested a new nematicidal agent, the symbiotic bacterium Xenorhabdus indica, which was molecularly identified (PV845100). Cell-free culture supernatants of Xenorhabdus spp. and their biogenic Ag-NPs were used in nematicidal assays. Meloidogyne incognita showed high mortality rates of 95.3%, 74.6%, and 72.6% after 72 h of treatment with the X. indica filtrate at three concentrations. At the same concentrations, biogenic Ag-NPs resulted in 82.0%, 90.0%, and 85.3% mortality rates, respectively. After 72 h, hatchability decreased by 53%, 74.6%, and 72.6% for the X. indica filtrate and 82.0%, 90.0%, and 85.3% for Ag-NPs. Quantitative real-time PCR (Q-PCR) revealed that Mi-Ache1 expression was lower in M. incognita second-stage juveniles (J2s) treated with the filtrate and Ag-NPs after 72 h compared to controls. Mi-Ache2 expression was also decreased, but only slightly. Furthermore, both the X. indica filtrate and biogenic Ag-NPs were safe in human lung (WI-38) and skin (HFB4) cell lines. These findings suggest that bacterial filtrates and their biogenic Ag-NPs could serve as cost-effective, environmentally friendly alternatives to commercial nematicides.

Root-knot nematodes ( Meloidogyne spp.) cause significant economic losses and have a profound impact on the agricultural sector, while commercial chemical nematicides have been found to cause pollution and are harmful to human health. The unique qualities and possible advantages of metal-based nanoparticles have gained considerable interest in plant disease control. This study synthesized, described, and evaluated CuONPs against the M. incognita nematode in terms of female biological cycle arrest, reduction of egg hatchability, and second juvenile mortality in pepper plants. It was done in both in vitro and open-field trials. Copper nanoparticles tested concurrently in graded concentrations (100, 75, 50, 25, and 12.5%) were evaluated. CuO nanoparticles were revealed to be effective nematode agents in the in vitro assay against eggs and second juvenile stages (J2s) of M. incognita , with a 100% concentration after 48 h of exposure, causing 87.9% larval mortality and 57.5% egg hatchability reduction. The open field experiment on pepper CuONPs application in direct irrigation showed 100% results with a concentration of 100%, an 84.4% decrease in egg masses/plant, a 92% decrease in J2s/100 g soil, and ultimately, an effect on the female's life cycle with an 83% decrease in number and an 89.6% reduction in galls/plant. Furthermore, pepper plants treated with CuONPs showed fresh and dry weights for the shoots and roots in open field trials. Finally, the safety effect of CuONPs on the growth of normal human cells was evidenced by its higher safety on normal human lung and skin cell lines (WI-38 and HFB4, respectively). CuONPs exhibited significantly effective growth parameters and strong nematicidal effects against nematodes, so they could be considered a safe and potential nanofertilizer and nematicide agent. Graphical abstract The importance of incorporating copper nanoparticles as a nematicidal particulate to improve the growth and yield of pepper plants, along with the fertility and health of the soil.

Background: The most important food legume crop in Egypt and worldwide is the faba bean (Vicia faba L.), which has the potential to greatly improve agricultural sustainability by providing benefits such as higher grain yields, product diversification, and better nutritional value. It accounts for nearly 90% of the world's faba bean production. These long-season faba bean crops are very vulnerable to damage from root-knot nematodes (RKNs), the main threat to vegetable farming. This study aimed to assess how RKN damage affects faba bean production in Egypt's climate, considering different planting dates and cultivars, as well as the effects these factors have on the plants' natural immunity against Meloidogyne incognita. Two field experiments were carried out on sandy soil in Egypt’s North Delta during the 2021–2022 and 2022–2023 seasons to study how three faba bean cultivars (Nubaria 1, Giza 716, and Giza 843) respond to three planting dates under drip irrigation when infected with nematodes. A split-plot design with three replications was used. In both seasons, the three faba bean varieties (Nubaria 1, Giza 716, and Giza 843) were randomly assigned within the subplots, while the main plots included planting dates of October 1, October 15, and November 1. Results: Data on RKN population density and gall index were collected to evaluate the severity of Meloidogyne incognita and to detect other types of nematodes. The three examined cultivars exhibited mild to moderate M. incognita infections, alongside slight infections of Xiphinema sp. and P. brachyurus during the 2021–2022 seasons, with 80% of the roots galled. In contrast, during the 2022–2023 growing season, RKN damage was unaffected by the planting dates. However, delaying the planting date from October 15 to November 1 increased RKN population densities in the 2021–2022 season, as well as resulted in increases in plant height, total chlorophyll content, and shading percentage of faba bean plants. Additionally, on October 15, the plant immune system appeared to activate against plant-parasitic nematodes through the up-regulation of antioxidant enzymes and increased glucanase and chitinase (PPO, POD, and PR3). Conclusions: According to our findings, the tested faba bean cultivars Giza 716 and Giza 843 are highly vulnerable to RKN, which raises concerns about the potential harm RKN could cause to commercial faba bean production and underscores the necessity of managing RKN. However, it can be asserted that fewer nematodes will infect faba beans once Nubaria 1 is planted in Egypt in mid-October.

Background The fall armyworm (FAW), Spodoptera frugiperda, and root-knot nematode, Meloidogyne incognita, are the most harmful agricultural pests, as they can persist in many environmental conditions and have a broad host range. Therefore, it is necessary to employ several control strategies, such as using biopesticides to reduce their population. This study aimed to designate and evaluate the effects of different concentrations of two methanolic algal extracts, Nostoc muscorum (Cyanobacteria) and Chlorella vulgaris (Chlorophyta), on 3rd instar FAW larvae and 2nd instar juvenile nematode stage (J2s) as a biological environmental strategy. Results Two algal extracts were evaluated against two dangerous plant pests. Subsequently, the expression profiles of acetylcholinesterase and cytochrome P450 genes will be studied. Both algal extracts had clear insecticide and nematicide effects, as shown in the results. Both extracts' highest concentration (100%) resulted in significantly higher mortality rates, which recorded 73% and 67% for FAW larvae and 94% and 88% for J2s, respectively. The expression levels of SfAChE, SfCYP9A60, MiAChE1, and MiCYP were lowered significantly when both target pests were treated with 75% N. muscorum after 24 hours post-treatment. The laboratory bioassay demonstrated that the extracts were highly biopesticide-active at 100% and 75% concentrations, which suppressed the immune response of FAW larvae and M. incognita to invade the host. Conclusions The two algal extracts resulted in various deficiencies in the normal growth and reproduction of insects and root-knot nematode larvae. This caused several issues, including a high mortality rate among FAW larvae, a reduced pupation percentage, and the production of abnormal pupae and moths, as well as juvenile mortality and a decrease in egg hatching rates in nematodes. Given that these algae are easily accessible and extensively cultivated, they can be effectively used by small-scale farmers to control fall armyworms and root-knot nematodes without relying on harmful chemical pesticides, thereby minimizing environmental pollution.

Root-knot nematodes (RKNs) are a vital pest that causes significant yield losses and economic damage to potato plants. The use of chemical pesticides to control these nematodes has led to environmental concerns and the development of resistance in the nematode populations. Endophytic fungi offer an eco-friendly alternative to control these pests and produce secondary metabolites that have nematicidal activity against RKNs. The objective of this study is to assess the efficacy of Aspergillus flavus (ON146363), an entophyte fungus isolated from Trigonella foenum-graecum seeds, against Meloidogyne incognita in filtered culture broth using GC–MS analysis. Among them, various nematicidal secondary metabolites were produced: Gadoleic acid, Oleic acid di-ethanolamide, Oleic acid, and Palmitic acid. In addition, biochemical compounds such as Gallic acid, Catechin, Protocatechuic acid, Esculatin, Vanillic acid, Pyrocatechol, Coumarine, Cinnamic acid, 4, 3-indol butyl acetic acid and Naphthyl acetic acid by HPLC. The fungus was identified through morphological and molecular analysis, including ITS 1–4 regions of ribosomal DNA. In vitro experiments showed that culture filtrate of A. flavus had a variable effect on reducing the number of egg hatchings and larval mortality, with higher concentrations showing greater efficacy than Abamectin. The fungus inhibited the development and multiplication of M. incognita in potato plants, reducing the number of galls and eggs by 90% and 89%, respectively. A. flavus increased the activity of defense-related enzymes Chitinas, Catalyse, and Peroxidase after 15, 45, and 60 days. Leaching of the concentrated culture significantly reduced the second juveniles’ stage to 97% /250 g soil and decreased the penetration of nematodes into the roots. A. flavus cultural filtrates via soil spraying improved seedling growth and reduced nematode propagation, resulting in systemic resistance to nematode infection. Therefore, A. flavus can be an effective biological control agent for root-knot nematodes in potato plants. This approach provides a sustainable solution for farmers and minimizes the environmental impact.

The utilization ofTrichoderma longibrachiatumfiltrate as a safe biocontrol method for producing zinc nanoparticles is a promising approach for managing pests and diseases in agricultural crops. The identification ofTrichodermasp. was achieved through PCR amplification and sequencing of 18s as ON203115, while the synthesis of ZnO-NPs was accomplished by employing Trichoderma filtration. The presence of ZnO-NPs was confirmed by observing a color change to dark green, along with the use of visible and UV spectrophotometers, and the formation and chemical structure of ZnO-NPs were examined. Direct exposure to ZnO-NPs exhibited a significant inhibitory effect on the growth ofFusarium oxysporumat 80.73% compared with control. Also, the percent mortality ofMeloidogyne incognitasecond juveniles stage (J2s) results showed 11.82%, 37.63%, 40.86%, and 89.65% after 6, 12, 24, and 72 h, respectively in vitro. Disease resistance was assessed in the greenhouse againstM. incognitaandF. oxysporumusing the drench application of ZnO-NPs. The application of ZnO-NPs significantly reduced the disease severity ofF. oxysporumand improved the quality and quantity of sweet pepper yield. In addition, the application of ZnO-NPs toM. incognitaresulted in a significant reduction in the number of nematode galls, egg masses per root, eggs/egg mass, and females by 98%, 99%, 99.9%, and 95.5% respectively.Furthermore, it was observed that the application of ZnO-NPs to pepper plants not only inhibited the growth ofF. oxysporumandM. incognita, but also promoted the recovery of pepper plants as indicated by improvements in stem length by 106%, root length 102%, fresh weight 112%, root fresh weight 107%, and leaf area 118% compared to healthy control plants. Additionally, real-time PCR application and DD-PCR technique revealed that the application of ZnO-NPs stimulated the secretion of certain enzymes. These findings suggest that the biosynthesized ZnO-NPs possess anti-nematode and antifungal properties, making them effective for protecting plants againstM. incognitaandF. oxysporuminvasion in soil. This study significantly contributes to our understanding of the nematicidal and fungicidal activities of ZnO-NPs in suppressing soil-borne diseases.

Background: DNA barcoding have been considered as a tool to facilitate species identification based on its simplicity and high-level accuracy in compression to the complexity and subjective biases linked to morphological identification of taxa. MaturaseK gene (MatK gene)of the chloroplast is very vital in the plant system which is involved in the group II intron splicing. The main objective of this study is to determine the relative utility of the “MatK” chloroplast gene for barcoding in 15 legume as a tool to facilitate species identification based on their simplicity and high-level accuracy linked to morphological identification of taxa.Methods and Results: MatKgene sequences were submitted to GenBank and the accession numbers were obtained with sequence length ranging from 730 to 1545 nucleotides. These DNA sequences were aligned with database sequence using PROMALS server,Clustal Omega server and Bioedit program. Maximum likelihood and neighbor-joining algorithms were employed for constructing phylogeny. Overall, these results indicated that the phylogenetic tree analysis and the evolutionary distances of an individual dataset of each species were agreed with a phylogenetic tree of all each other consisting of two clades, the first clade comprising(Enterolobium contortisiliquum, Albizia lebbek), Acacia saligna,Leucaena leucocephala, Dichrostachys Cinerea, (Delonix regia, Parkinsonia aculeata), (Senna surattensis, Cassia fistula, Cassia javanica)andSchotia brachypetalawere more closely to each other, respectively. The remaining four species ofErythrina humeana, (Sophora secundiflora, Dalbergia Sissoo, Tipuana Tipu)constituted the second clade.Conclusion: Moreover, their sequences could be successfully utilized in single nucleotide polymorphism or as part of the sequence as DNA fragment analysis utilizing polymerase chain reaction in plant systematic. Therefore,MatKgene is considered promising a candidate for DNA barcoding in the plant family Fabaceae and provides a clear relationship between the families.

Background: Plant-parasitic nematodes are one of the major constraints to soybean production around the world. Plant-parasitic nematodes cause an estimated $78 billion in annual crop losses worldwide, with a 10–15% crop yield loss on average. Consequently, finding and applying sustainable methods to control diseases associated with soybean is currently in serious need.Methods: In this study, we isolated, purified, characterized, and identified a novel cyanobacterial strainOscillatoriasp. (blue-green alga). Based on its microscopic examination and 16S rRNA gene sequence, the aqueous and methanolic extracts ofOscillatoriawere used to test their nematicidal activity againstMeloidogyne incognitahatchability of eggs after 72 h of exposure time and juvenile mortality percentagein vitroafter 24, 48, and 72 h of exposure time and reduction percentage of galls, eggmass, female number/root, and juveniles/250 soil. Also, the efficacy of the extract on improving the plant growth parameter and chlorophyll content under greenhouse conditions on soybean plant cv. Giza 111 was tested. Finally, the expression of PR-1, PR-2, PR-5, and PR15 (encoding enzymes) genes contributing to plant defense in the case ofM. incognitainvasion was studied and treated withOscillatoriaextract.Results: The aqueous and methanolic extracts ofOscillatoriasp. had nematicidal activity againstM. incognita. The percentage of mortality and egg hatching ofM. incognitawere significantly increased with the increase of time exposure toOscillatoriaextract 96.7, 97, and 98 larvae mortality % with S concentration after 24, 48, and 72 h of exposure time. The aqueous extract significantly increased the percentage of Root-Knot nematodes (RKN) of egg hatching, compared with Oxamyl and methanol extract at 96.7 and 97% after 72 h and 1 week, respectively. With the same concentration in the laboratory experiment. Furthermore, water extracts significantly reduced the number of galls in soybean root, egg masses, and female/root by 84.1, 87.5, and 92.2%, respectively, as well as the percentage of J2s/250 g soil by 93.7%. Root, shoot lengths, dry weight, number of pods/plant, and chlorophyll content of soybean treated withOscillatoriawater extract were significantly higher than the control increasing by 70.3, 94.1, 95.5, and 2.02%, respectively. The plant defense system's gene expression was tracked using four important pathogenesis-related genes, PR-1, PR-2, PR-5, and PR15, which encode enzymes involved in plant defense.Conclusions: Oscillatoriaextract is a potential nematicide against root-knot nematode invasion in soybean.

Cotton (Gossypium hirsutum) is a global cash crop which has gained importance in earning foreign exchange for each country. Bacterial blight caused by Xanthomonascitri subsp. malvacearum (Xcm) has been a seriousdisease in Pakistan’s cotton belt on multiple occasions. Bacterium was isolated and identified through various biochemical and diagnostic tests wherehypersensitivity reaction, Gram staining, KOH (potassium hydroxide), catalase, starch hydrolysis, lecithinase and Tween 80 hydrolysis tests confirmed bacterium as Gram-negative and plant pathogenic. Xcm perpetuation assays wereevaluated on various cotton varieties under glasshouse conditions in completely randomized design by three different methods, wherein the scratch method proved to be the best upon CIM-496 and showed 83.33% disease incidence as compared with the other two methods, where Bt-3701 responded with 53.33% incidence via the spray gun method, and 50% with the water splash method on CIM-616, as compared with the control. Similarly, for disease severity percentage, Bt-3701 was pragmatic with 47.21% through scratch method, whereas, in the spray gun method, 45.51% disease severity was noted upon Bt-802, and 31.27% was calculated on Cyto-179 through the water splash method. Owing to the unique antibacterial properties of aqueous plant extracts, the poison food technique showed Aloe vera, Mentha piperita, Syzygiumcumini and Azadirachta indica with 17.77, 29.33, 18.33 and 20.22 bacterial colonies counted on nutrient agarmedium petri plate, respectively, as compared with the control. Measurement of the inhibition zone by disk diffusion technique showed Mentha piperita, Syzygiumcumini, Citrus limon, Moringa oleifera and Syzygium aromaticum to present the most promising results by calculating the maximum diameter of the inhibition zone, viz., 8.58, 8.55, 8.52, 8.49 and 8.41 (mm), respectively, at the highest tested concentration (75 ppm, parts per million) compared with the control. It is probable that the decoction’s interaction with the pathogen population on the host plant will need to be considered in future experiments. However, at this moment, more research into the effective management of cotton bacterial blight by plant extracts in terms of concentration determination and development of biopesticides will provide future avenues to avoid environmental pollution.