Background: Microbial cultures are extensively used as environment friendly ways for biological control of parasitic pests, including the root-knot nematodes, alternative to the use of chemical nematicides. The present study was conducted to isolate some lytic rhizobacteria and examine their nematicidal activity againstMeloidogyne incognitaJ₂mortality and egg hatching in in vitro test.Results: Lytic Rhizobacteria were isolated from soil samples adhering to tomato plant roots from different localities at Giza governorate, Egypt. Six bacterial isolates, exhibited high efficacy against root-knot nematodes, were identified based on the analysis of the 16S rRNA gene sequence asPseudomonas aeruginosa,Paenibacillus polymyxa,Lysinibacillus sphaericus,Bacillus cereus,Bacillus subtilis, andAchromobacter xylosoxidans. These strains showed high production of chitinase, chitosanase, and protease using colloidal chitin and soluble chitosan as carbon sources. Two strains,Paenibacillus polymyxaandBacillus subtilis, produced the highest levels of chitinase in the media. Except forPseudomonas aeruginosa, all the bacterial strains produced high levels of chitosanase.Conclusion: The results revealed that high amounts of protease were, however, secreted byPseudomonas aeruginosaas compared to the other strains. In in vitro tests, all the bacterial culture filtrates potentially displayed nematicidal effect inM. incognitaegg hatching and an obvious increase in J₂mortality as compared to control.Paenibacillus polymyxacaused 100% juvenile mortality followed byBacillus subtilis97.25%,Bacillus cereus94%,Achromobacter xylosoxidans93%,Lysinibacillus sphaericus92%, andPseudomonas aeruginosa84.29% after 48 h of exposure, as compared to control.

Spodoptera frugiperda, the fall armyworm (FAW), is a highly invasive polyphagous insect pest that is considered a source of severe economic losses to agricultural production. Currently, the majority of chemical insecticides pose tremendous threats to humans and animals besides insect resistance. Thus, there is an urgent need to develop new pest management strategies with more specificity, efficiency, and sustainability. Chitin-degrading enzymes, including chitinases, are promising agents which may contribute to FAW control. Chitinase-producing microorganisms are reported normally in bacteria and fungi. In the present study, Serratia marcescens was successfully isolated and identified from the larvae of Spodoptera frugiperda. The bacterial strain NRC408 displayed the highest chitinase enzyme activity of 250 units per milligram of protein. Subsequently, the chitinase gene was cloned and heterologously expressed in E. coli BL21 (DE3). Recombinant chitinase B was overproduced to 2.5-fold, driven by the T7 expression system. Recombinant chitinase B was evaluated for its efficacy as an insecticidal bioagent against S. frugiperda larvae, which induced significant alteration in subsequent developmental stages and conspicuous malformations. Additionally, our study highlights that in silico analyses of the anticipated protein encoded by the chitinase gene (ChiB) offered improved predictions for enzyme binding and catalytic activity. The effectiveness of (ChiB) against S. frugiperda was evaluated in laboratory and controlled field conditions. The results indicated significant mortality, disturbed development, different induced malformations, and a reduction in larval populations. Thus, the current study consequently recommends chitinase B for the first time to control FAW.

During the last decade, enormous research efforts have been directed at identifying potent microorganisms as sustainable green cell factories for eco-friendly pigments. Talaromyces atroroseus has recently been shown to excrete large amounts of azaphilone mycotoxin-free red pigment mixture comprising some known coloring components together with many uncharacterized metabolites. In this study, a new Talaromyces atroroseus isolate was identified via sequencing of the fragment of the nuclear ribosomal gene cluster containing internal transcribed spacers and 5.8S rRNA gene. The parameters that affected the level of pigment production were optimized in uncommon static conditions of culture and genetic improvement, via γ-irradiation, to improve pigment yield. Moreover, chemical characterization using LC/MS and skin safety test of the target pigment mixture were precisely conducted to maximize its benefits as a natural and safe red pigment for wool fabrics. Molecular identification via the sequencing of the ITS of the rDNA encoding gene cluster revealed that the fungal isolate TRP-NRC was T. atroroseus TRP-NRC (deposited in GenBank under accession number MW282329). In the static conditions of culture, pigment production was dramatically enhanced to 27.36 g/L in an optimum yeast malt peptone medium of 2% mannitol at pH 2−4.5 and 30 °C for 7 days of incubation. Under exposure to a 400-Gy γ-radiation dose, pigment yield was increased to a 3-fold level higher than that recorded for the wild type. Based on the inter-simple sequence repeats (ISSR), as a molecular marker tool, the wild-type T. atroroseus TRP-NRC strain and its mutants were discriminated. The UHPLC/HRESI-MS analytical tool characterized 60 metabolites, including many unknown molecules, at appropriate concentrations. It is worthy to note that four mitorubrin derivatives were identified for the first time in T. atroroseus, i.e., mitorubrinolamine acetate, dihydro-PP-O, mitorobrinal, and mitorubrinol. The range of irritation indexes (0−0.1) demonstrated an adequate skin safety after the direct local application of the pigment mixture. Finally, the pigment mixture exhibited a remarkably good dyeing ability in wool fabrics, with high-fastness properties. Because of its sustainable and economic production, the target red pigment mixture may be applied in the future in textile, food, cosmetics, or different pharmaceutical industries after extensive conventional safety and toxicity studies, which are currently under consideration.

The production of industrial enzymes such as xylanase using sufficient cost-effective substrates from potent microorganisms is considered economically feasible. Studies have reported castor cake (Ricinus communis) as the most potent and inexpensive alternative carbon source for production of xylanase C by using Aspergillus terreus (A. terreus). A. terreus strain RGS Eg-NRC, a local isolate from agro-wastes, was first identified by sequencing the internal transcribed spacer region of a nuclear DNA encoding gene cluster deposited in GenBank (accession number MW282328). Before optimization of xylanase production, A. terreus produced 20.23 U/g of xylanase after 7 days using castor cake as a substrate in a solid-state fermentation (SSF) system that was employed to achieve ricin detoxification and stimulate xylanase production. Physicochemical parameters for the production of xylanase were optimized by using a one-variable-at-a-time approach and two statistical methods (two-level Plackett–Burman design and central composite design, CCD). The maximum xylanase yield after optimization was increased by 12.1-fold (245 U/g). A 60–70% saturation of ammonium sulfate resulted in partially purified xylanase with a specific activity of 3.9 IU/mg protein. At 60 °C and pH 6, the partially purified xylanase had the highest activity, and the activation energy (Ea) was 23.919 kJmol. Subsequently, antioxidant capacity and cytotoxicity tests in normal Ehrlich ascites carcinoma human cells demonstrated xylooligosaccharides produced by the xylanase degradation of xylan as a potent antioxidant and moderate antitumor agent. Further investigations with sodium dodecyl sulfate polyacrylamide gel electrophoresis then determined the molecular weight of partially purified xylanase C to be 36 kDa. Based on the conserved regions, observations revealed that xylanase C belonged to the glycosyl hydrolase family 10. Next, the xylanase-encoding gene (xynC), which has an open reading frame of 981 bp and encodes a protein with 326 amino acids, was isolated, sequenced, and submitted to the NCBI GenBank database (accession number LC595779.1). Molecular docking analysis finally revealed that Glu156, Glu262, and Lys75 residues were involved in the substrate-binding and protein-ligand interaction site of modeled xylanase, with a binding affinity of −8.7 kcal. mol−1. The high production of safe and efficient xylanase could be achieved using economical materials such as Ricinus communis.

Fall armyworm, Spodoptera frugiperda, is a serious agricultural pest native to tropical and subtropical regions of the Western Hemisphere and has invaded Africa and further spread into most countries of Asia within two years. In Egypt, researchers have conducted thorough investigations into the behavior of the fall armyworm and various methods to manage its impact. This study aims to further our understanding of the genetic diversity of fall armyworm populations in Egypt. By collecting specimens from five provinces across the country, we sought to analyze their genetic makeup. Through examination of partial sequences of the mitochondrial cytochrome oxidase subunit I (COI), we identified three distinct haplotypes. Phylogenetic analysis suggests that the primary sources of Spodoptera frugiperda in Egypt likely stem from both Asian and African origins. Employing the PCR-RFLP technique on the complete COI sequence, we were able to discern genotype patterns within the fall armyworm population. Our findings indicate the presence of two distinct strains—the Corn and Rice strains—within Egypt. This research contributes essential insights into the genetic diversity of insects in Egypt, providing valuable knowledge that can inform more effective strategies for managing this agricultural pest.

Background: Increasing chemical nematicide and fertilizer application has disturbed the natural balance and increased human health risks, which in turn compelled and increased the urgency to discover novel and more safe and effective biological tools to control root-knot nematode (Meloidogyne incognita) distributed throughout Egypt. Objective: Isolation and screening of rhizobacteria from soil samples was the first step. The second step was the evaluation of the isolated rhizobacteria capability as nematicides under laboratory and screenhouse conditions. The third was to employ protoplast fusion as genetic technique to improve the nematicidal effect of rhizobacterial bacteria strains and comparison between parent and fusant protein profiles to analyze the genetic recombination among them. Materials and methods: Serial dilution method was used to isolate rhizobacteria on Tryptic Soy Agar plates. The evaluation test against M. incognita J₂ of bacterial isolates was achieved under laboratory conditions and nematode parameters under screenhouse. The most potent rhizobacteria were exposed to molecular identification using 16s rDNA sequencing. Bacillus thuringiensis subsp tenebrionis (Bt) was evaluated for the first time as a bioagent that acted as a nematicide. Protoplast fusion was employed between the most potent bacterial strain, Bacillus cereus (Bc) and B. thuringiensis subsp tenebrionis (Bt). Selection of bacterial fusants was achieved on complete media containing selectable antibiotics marker. Parental and fusant strains were evaluated against J₂ under laboratory and screenhouse conditions and their ability in plant-growth promotion by assessment of plant parameters. SDS-PAGE analysis was used to analyze protein profiles. Results and conclusion: Out of 15 bacterial isolates, NRC12 recorded the highest percentage mortality 88.3% after 24 h compared with control. NRC12 was identified as B. cereus NRC12 (Bc) and deposited in Genbank under accession number MW548408. Protoplast fusion between B. cereus (Bc) and B. thuringiensis (Bt) resulted in formation of 10 stable bacterial fusants that gave higher nematicidal effect compared with parental strains. Bacterial fusant, F7, achieved the highest mortality and reduction in J₂ in soil by 98.3 and 87.19% under laboratory and screenhouse conditions, respectively. The highest reduction in the number of galls and egg masses on root system was also recorded by F7 with 77.18 and 72.35%, respectively, compared with its parents. Also, F7 registered the highest significant (P≤0.05) increment in length, fresh weight, and dry weights in the shoot system of eggplant in pot experiments. The bacterial fusant, F7, exhibited more ability to fix atmospheric nitrogen compared with bacterial parents. Protein profile of F7 proved that this fusant was the only one that acquired equal protein bands from each parent. The highest frequency of genetic recombination might occur in F7 and subsequently, induced effective nematicidal effect more than its parents.