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Water contamination with heavy metals drastically affects plant growth and development. It is more dangerous than other contamination sources due to its cumulative impact over time through plant irrigation. Lead (Pb) is one of the most prevalent and hazardous heavy metals that significantly impede plant growth and development in terrestrial ecosystems. α- lipoic acid (ALA) is a naturally occurring dithiol antioxidant, strong ROS scavenger and metal chelator. Herein, this study was conducted to explore the role of exogenous ALA (0.1 mM) in reducing the Pb-phytotoxicity in tomato seedlings irrigated with Pb contaminated water (250 ppm for 45 days after transplanting). Exposing plants to Pb stress significantly inhibited plant growth, photosynthetic pigments, mineral homeostasis and cell membrane integrity compared to the control plants. In contrast, ALA application markedly revealed a significant improvement in these traits by reinforcing the antioxidant defense systems including superoxide dismutase, guaiacol peroxidase, catalase, glutathione reductase and the major reduced components of ascorbate glutathione cycle. Moreover, ALA significantly enhanced N, P, K, Ca and Fe, reduced Pb uptake and restricted the Pb-induced oxidative damage by reducing the hydrogen peroxide, malondialdehyde and inhibiting the activity of Lipoxygenase. The regression analysis exhibited that ALA demonstrated various significant relationships between the uptake of Pb and the major components of ascorbate glutathione cycle in both leaf and root. In conclusion, our findings deciphered the potential functions of ALA in alleviating Pb-phytotoxicity and enhancing the redox balance of tomato seedlings by enhancing the ratio between the reduced glutathione/oxidized glutathione and reduced ascorbate/dehydroascorbate.

Background Basil ( Ocimum sp.) exhibits significant morphological and genetic diversity. This variation provides an opportunity to identify novel traits that can be used in breeding programs to improve the productivity, quality, and disease resistance of basil plants. The integration of morphological and genetic data for basil varieties can improve our understanding of biodiversity, conservation, and breeding programs. Results In 2019, we conducted a comprehensive investigation on 25 basil landraces collected from 12 Egyptian governorates to explore their morphological and genetic diversity. Morphological characterization revealed variability in plant vigor, flower color, cyme shape, and leaf shape, indicating distinct growth patterns and potential for specific applications. Productivity and biochemical evaluation demonstrated significant variation in yield and oil distillation, identifying top-performing landraces L5, L11, and L24 that can be used in breeding programs to optimize performance and reduce environmental impact. The genetic diversity of the landraces was investigated using 11 SCoT primers revealed high levels of genetic diversity among landraces, with a wide range of polymorphism variation. The phylogenetic analysis identified two distinct clades, providing valuable insights into genetic diversity and relationships between different landraces. An interesting observation was made in the study, whereby L6 and L13, collected from Fayoum and Port-Said, respectively, were found to be the closest landraces. Following closely were L7 and L14, which were also collected from the same governorates. These findings have significant implications for the conservation of these landraces, as they may have evolved from similar species. Conclusions This study sheds light on the genetic diversity and relationships among 25 Egyptian basil landraces. Using SCoT markers, a high level of polymorphism was detected, indicating significant variation in the genetic makeup of the landraces. The study also revealed interesting observations regarding the relationships among the landraces, with some landraces appearing to have evolved from similar species. The phylogenetic analysis provided insights into the genetic relationships among the landraces, which can guide conservation efforts and breeding programs. Overall, this study provides valuable information for researchers, breeders, and farmers involved in the conservation, breeding, and utilization of basil genetic resources in Egypt.

Understanding the role of cysteine-rich receptor-like kinases (CRKs) in plant defense mechanisms is crucial for enhancing wheat resistance to leaf rust fungus infection. Here, we identified and verified 164 members of the CRK gene family using the Triticum aestivum reference version 2 collected from the international wheat genome sequencing consortium (IWGSC). The proteins exhibited characteristic features of CRKs, including the presence of signal peptides, cysteine-rich/stress antifungal/DUF26 domains, transmembrane domains, and Pkinase domains. Phylogenetic analysis revealed extensive diversification within the wheat CRK gene family, indicating the development of distinct specific functional roles to wheat plants. When studying the expression of the CRK gene family in near-isogenic lines (NILs) carrying Lr57- and Lr14a-resistant genes, Puccinia triticina, the causal agent of leaf rust fungus, triggered temporal gene expression dynamics. The upregulation of specific CRK genes in the resistant interaction indicated their potential role in enhancing wheat resistance to leaf rust, while contrasting gene expression patterns in the susceptible interaction highlighted potential susceptibility associated CRK genes. The study uncovered certain CRK genes that exhibited expression upregulation upon leaf rust infection and the Lr14a-resistant gene. The findings suggest that targeting CRKs may present a promising strategy for improving wheat resistance to rust diseases.

Powdery mildew, caused by Blumeria graminis f. sp. hordei (Bgh), severely impacts global barley Hordeum vulgare L. (Hv) production. This investigation evaluated Egyptian barley genotypes to identify novel resistance sources and molecular markers for breeding programs. Phenotypic assessments at the seedling (growth stage, GS 32) and adult plant (GS 55–59) stages under controlled and field conditions, combined with SSR marker analysis, revealed distinct resistance profiles. Genotypes Giza 123, Giza 125, and G8 exhibited strong resistance, with Giza 123 displaying Mlo-mediated immunity. Susceptible genotypes (Giza 126, G1, G2, and G4) showed rapid disease progression (IT4; up to 80% severity). Intermediate genotypes (G5, G6, and G9) suggested quantitative resistance. Simple sequence repeat (SSR) analysis linked the EBmac0603 primer 160 bp allele to resistance and the 149 bp allele to susceptibility. The EBmac0603 primer 185 bp allele correlated with partial resistance, highlighting its utility in marker-assisted selection (MAS). The integration of phenotypic and molecular data identified Giza 123 and G8 as prime candidates for breeding, emphasizing the need for strategies like gene pyramiding or quantitative resistance incorporation in susceptible lines. This study underscores the value of Egypt’s barley diversity in advancing durable disease resistance through targeted breeding and molecular tools.

Key messageA stress induced calcium-binding protein, RD20/CLO3 interacts with the alpha subunit of the heterotrimeric G-protein complex in Arabidopsis and affects etiolation and leaf morphology.Heterotrimeric G proteins and calcium signaling have both been shown to play a role in the response to environmental abiotic stress in plants; however, the interaction between calcium-binding proteins and G-protein signaling molecules remains elusive. We investigated the interaction between the alpha subunit of the heterotrimeric G-protein complex, GPA1, of Arabidopsis thaliana with the calcium-binding protein, the caleosin RD20/CLO3, a gene strongly induced by drought, salt and abscisic acid. The proteins were found to interact in vivo by bimolecular fluorescent complementation (BiFC); the interaction was localized to the endoplasmic reticulum and to oil bodies within the cell. The constitutively GTP-bound GPA1 (GPA1QL) also interacts with RD20/CLO3 as well as its EF-hand mutant variations and these interactions are localized to the plasma membrane. The N-terminal portion of RD20/CLO3 was found to be responsible for the interaction with GPA1 and GPA1QL using both BiFC and yeast two-hybrid assays. RD20/CLO3 contains a single calcium-binding EF-hand in the N-terminal portion of the protein; disruption of the calcium-binding capacity of the protein obliterates interaction with GPA1 in in vivo assays and decreases the interaction between the caleosin and the constitutively active GPA1QL. Analysis of rd20/clo3 mutants shows that RD20/CLO3 plays a key role in the signaling pathway controlling hypocotyl length in dark grown seedlings and in leaf morphology. Our findings indicate a novel role for RD20/CLO3 as a negative regulator of GPA1.

Understanding the role of cysteine-rich receptor-like kinases (CRKs) in plant defense mechanisms is crucial for enhancing wheat resistance to leaf rust fungus infection. Here, we identified and verified 164 members of the CRK gene family using the Triticum aestivum reference version 2 collected from the international wheat genome sequencing consortium (IWGSC). The proteins exhibited characteristic features of CRKs, including the presence of signal peptides, cysteine-rich/stress antifungal/DUF26 domains, transmembrane domains, and Pkinase domains. Phylogenetic analysis revealed extensive diversification within the wheat CRK gene family, indicating the development of distinct specific functional roles to wheat plants. When studying the expression of the CRK gene family in near-isogenic lines (NILs) carrying Lr57- and Lr14a-resistant genes, Puccinia triticina, the causal agent of leaf rust fungus, triggered temporal gene expression dynamics. The upregulation of specific CRK genes in the resistant interaction indicated their potential role in enhancing wheat resistance to leaf rust, while contrasting gene expression patterns in the susceptible interaction highlighted potential susceptibility associated CRK genes. The study uncovered certain CRK genes that exhibited expression upregulation upon leaf rust infection and the Lr14a-resistant gene. The findings suggest that targeting CRKs may present a promising strategy for improving wheat resistance to rust diseases.

Background The caleosin genes encode proteins with a single conserved EF hand calcium-binding domain and comprise small gene families found in a wide range of plant species. Some members of the gene family have been shown to be upregulated by environmental stresses including low water availability and high salinity. Caleosin 3 from wheat has been shown to interact with the α-subunit of the heterotrimeric G proteins, and to act as a GTPase activating protein (GAP). This study characterizes the size and diversity of the gene family in wheat and related species and characterizes the differential tissue-specific expression of members of the gene family. Results A total of 34 gene family members that belong to eleven paralogous groups of caleosins were identified in the hexaploid bread wheat, T. aestivum. Each group was represented by three homeologous copies of the gene located on corresponding homeologous chromosomes, except the caleosin 10, which has four gene copies. Ten gene family members were identified in diploid barley, Hordeum vulgare , and in rye, Secale cereale, seven in Brachypodium distachyon , and six in rice, Oryza sativa . The analysis of gene expression was assayed in triticale and rye by RNA-Seq analysis of 454 sequence sets and members of the gene family were found to have diverse patterns of gene expression in the different tissues that were sampled in rye and in triticale, the hybrid hexaploid species derived from wheat and rye. Expression of the gene family in wheat and barley was also previously determined by microarray analysis, and changes in expression during development and in response to environmental stresses are presented. Conclusions The caleosin gene family had a greater degree of expansion in the Triticeae than in the other monocot species, Brachypodium and rice. The prior implication of one member of the gene family in the stress response and heterotrimeric G protein signaling, points to the potential importance of the caleosin gene family. The complexity of the family and differential expression in various tissues and under conditions of abiotic stress suggests the possibility that caleosin family members may play diverse roles in signaling and development that warrants further investigation.

The Omicron (B.1.1.529) variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was initially identified in November 2021 in South Africa and Botswana, as well as in a sample from a traveller from South Africa in Hong Kong 1 , 2 . Since then, Omicron has been detected globally. This variant appears to be at least as infectious as Delta (B.1.617.2), has already caused superspreader events 3 , and has outcompeted Delta within weeks in several countries and metropolitan areas. Omicron hosts an unprecedented number of mutations in its spike gene and early reports have provided evidence for extensive immune escape and reduced vaccine effectiveness 2 , 4 – 6 . Here we investigated the virus-neutralizing and spike protein-binding activity of sera from convalescent, double mRNA-vaccinated, mRNA-boosted, convalescent double-vaccinated and convalescent boosted individuals against wild-type, Beta (B.1.351) and Omicron SARS-CoV-2 isolates and spike proteins. Neutralizing activity of sera from convalescent and double-vaccinated participants was undetectable or very low against Omicron compared with the wild-type virus, whereas neutralizing activity of sera from individuals who had been exposed to spike three or four times through infection and vaccination was maintained, although at significantly reduced levels. Binding to the receptor-binding and N-terminal domains of the Omicron spike protein was reduced compared with binding to the wild type in convalescent unvaccinated individuals, but was mostly retained in vaccinated individuals. Sera from unvaccinated, vaccinated, and previously infected and vaccinated individuals show reduced neutralizing and spike protein-binding activity towards the Omicron (B.1.1.529) variant of SARS-CoV-2 compared to other variants.

Plasma accelerators (Esary et al 2009 Rev. Mod. Phys. 81 1229) are a potentially important source of high energy, low emittance electron beams with high peak currents generated within a relatively short distance. As such, they may have an important application in the driving of coherent light sources such as the Free Electron Laser (FEL) which operate into the x-ray region (McNeil and Thompson 2010 Nat. Photon. 4 814-21). While novel plasma photocathodes (Hidding et al 2012 Phys. Rev. Lett. 108 035001) may offer orders of magnitude improvement to the normalized emittance and brightness of electron beams compared to Radio Frequency-driven accelerators, a substantial challenge is the energy spread and chirp of beams, which can make FEL operation impossible. In this paper it is shown that such an energy-chirped, ultrahigh brightness electron beam, with dynamically evolving current profile due to ballistic bunching at moderate energies, can generate significant coherent radiation output via the process of Coherent Spontaneous Emission (CSE) (Campbell and McNeil 2012 Proc. FEL2012 (Nara, Japan)). While this CSE is seen to cause some FEL-induced electron bunching at the radiation wavelength, the dynamic evolution of the energy chirped pulse dampens out any high-gain FEL interaction. This work may offer the prospect of a future plasma driven FEL operating in the high-gain Self Amplified CSE mode.

The present study examined the impacts of varying amounts of selenium nanoparticles (Se-NPs) as a natural antioxidant and metabolic regulator on growth performance, antioxidant capacity, digestive enzymes and immune resistance of Oreochromis niloticus challenged to Aspergillus flavus infection. For 60 days, fish were fed the experimental diet of 30% crude protein up to apparent satiation three times a day. Se-NPs were added to the control diet at different levels of 0.0 (control), 0.5 (T1), 1.0 (T2) and 1.5 (T3) mg/kg diet to fed monosex Nile tilapia fingerlings with average initial weight (4.5 ± 0.5 g). Fish were randomly distributed in 12 tanks 100 L at a density of 20 fish per tank after 2-week acclimation to represent four treatments in triplicates. The results indicated that the growth indices, feed efficiency and survival rate were significantly enhanced ( P < 0.05) by incorporating Se-NPs up to 1 mg/kg diet. Furthermore, the haemato-biochemical parameters, digestive enzymes activity and antioxidant capacity of the fish were significantly improved ( P < 0.05) at T2. When the fish were challenged with Aspergillus flavus , a decreasing mortality rate was observed, which clearly shows that selenium nanoparticles boosted the fish’s immune response at T2. The intestinal morphology as villus length, villus width, muscular fibres layer thickness and absorption intestinal zone after challenged with A. flavus infection were considerably enhanced ( P < 0.05) by incorporating all Se-NP levels. Histopathological score significantly improved ( P < 0.05) for the hepatopancreatic, intestinal, gills and muscle tissues at T2. The present study concludes that selenium nanoparticles up to 1.0 mg/kg diet can be efficiently used in tilapia feed to help boost fish production, immune system response and histopathological parameters.