Biological control of the predominant seed-borne fungi of tomato by using plant extracts

Aqueous extracts from five wild traditional medicinal plants (Achillea fragrantissima, Balanites aegyptiaca, Peganum harmala, Rumex vesicarius, and Urtica urens) which were collected from different locations in Egypt were tested against the predominant fungal pathogens (Alternaria alternata f. sp. lycopersici,  A.  solani, Fusarium oxysporum f. sp. lycopersici and Rhizoctonia solani) infested tomato seeds . All the aqueous plant extracts significantly inhibited the mycelial growth and spore germination of these fungi, but the extract of A. fragrantissima exhibited the strongest antifungal activity. The maximum seed germination, plant emergence and seedling vigor was detected after the treatment of tomato seeds with 10% A. fragrantissima extract. Pathogenicity testing of tomato seeds by predominant fungi indicated positive infection of tomato seeds but A. solani had the most aggressive infection. In greenhouse experiment, the aqueous A. fragrantissima extract reduced disease severity but increased total pigments, total phenolics and fruit yield

Does Exogenous Application of Kinetin and Spermine Mitigate the Effect of Seawater on Yield Attributes and Biochemical Aspects of Grains?

A pot experiment was conducted to evaluate the effect of grain presoaking in kinetin ( 0.1 mM), spermine (0.3 mM) and their interaction on yield components and biochemical aspects of yielded grains of wheat plants irrigated with 25% seawater . Seawater induced marked reduction in biochemical aspects of yielded grains especially carbohydrates content, nitrogenous constituents, total protein and nucleic acids contents as well as proline and organic acids (citric and keto-acids) content. Conversely, seawater stress increased phosphorus and ions (Na+, K+ and Cl-) content. Application of kinetin or spermine appeared to mitigate the effect of seawater stress on wheat yield and the biochemical aspects of yielded grains. The effect was more pronounced with kinetin + spermine treatment

Wheat can acclimate to seawater by pretreatment with kinetin and spermine through osmotic adjustment and solutes allocation

A key issue in salt adaptation is the osmotic adjustment, therefore, during ear emergence the effect of exogenous application of kinetin and spermine on osmotic pressure (OP) and solutes allocation (total soluble sugars, total soluble nitrogen, proline, organic acids and inorganic ions (Na+, K+, Ca2+, Mg2+ and Cl-) were quantified in flag leaf of wheat plants irrigated by seawater at 25%. Seawater salinity induced significant increase in osmotic pressure. Furthermore, seawater stress induced marked increase in total soluble sugars, total soluble nitrogen, proline, organic acids, as well as Na+, K+, Ca++, Mg++, Cl- and P+++ in wheat flag leaf. On the other hand, seawater decreased SPR, SAR and PAR in flag leaves of wheat plants. Grain priming with kinetin, spermine or their interaction appeared to mitigate the ill effect of seawater on wheat plants by increasing its own capability to be more tolerant against seawater salinity by inducing additional increase in osmotic pressure and the osmolytes concentrations in flag leaf during ear emergence. Moreover, the effect was more pronounced with the interaction of kinetin and spermine treatment

Biological and molecular characterization of fEg-Eco19, a lytic bacteriophage active against an antibiotic-resistant clinical Escherichia coli isolate

Characterization of bacteriophages facilitates better understanding of their biology, host specificity, genomic diversity, and adaptation to their bacterial hosts. This, in turn, is important for the exploitation of phages for therapeutic purposes, as the use of uncharacterized phages may lead to treatment failure. The present study describes the isolation and characterization of a bacteriophage effective against the important clinical pathogen Escherichia coli, which shows increasing accumulation of antibiotic resistance. Phage fEg-Eco19, which is specific for a clinical E. coli strain, was isolated from an Egyptian sewage sample. Phage fEg-Eco19 formed clear, sharp-edged, round plaques. Electron microscopy showed that the isolated phage is tailed and therefore belongs to the order Caudovirales, and morphologically, it resembles siphoviruses. The diameter of the icosahedral head of fEg-Eco19 is 68 +/- 2 nm, and the non-contractile tail length and diameter are 118 +/- 0.2 and 13 +/- 0.6 nm, respectively. The host range of the phage was found to be narrow, as it infected only two out of 137 clinical E. coli strains tested. The phage genome is 45,805 bp in length with a GC content of 50.3% and contains 76 predicted genes. Comparison of predicted and experimental restriction digestion patterns allowed rough mapping of the physical ends of the phage genome, which was confirmed using the PhageTerm tool. Annotation of the predicted genes revealed gene products belonging to several functional groups, including regulatory proteins, DNA packaging and phage structural proteins, host lysis proteins, and proteins involved in DNA/RNA metabolism and replication.Peer reviewe

Identification and Functional Analysis of Temperate Siphoviridae Bacteriophages of Acinetobacter baumannii

Acinetobacter baumannii is an opportunistic pathogen that presents a serious clinical challenge due to its increasing resistance to all available antibiotics. Phage therapy has been introduced recently to treat antibiotic-incurable A. baumannii infections. In search for new A. baumannii specific bacteriophages, 20 clinical A. baumannii strains were used in two pools in an attempt to enrich phages from sewage. The enrichment resulted in induction of resident prophage(s) and three temperate bacteriophages, named vB_AbaS_fEg-Aba01, vB_AbaS_fLi-Aba02 and vB_AbaS_fLi-Aba03, all able to infect only one strain (#6597) of the 20 clinical strains, were isolated. Morphological characteristics obtained by transmission electron microscopy together with the genomic information revealed that the phages belong to the family Siphoviridae. The ca. 35 kb genomic sequences of the phages were >99% identical to each other. The linear ds DNA genomes of the phages contained 10 nt cohesive end termini, 52–54 predicted genes, an attP site and one tRNA gene each. A database search revealed an >99% identical prophage in the genome of A. baumannii strain AbPK1 (acc. no. CP024576.1). Over 99% identical prophages were also identified from two of the original 20 clinical strains (#5707 and #5920) and both were shown to be spontaneously inducible, thus very likely being the origins of the isolated phages. The phage vB_AbaS_fEg-Aba01 was also able to lysogenize the susceptible strain #6597 demonstrating that it was fully functional. The phages showed a very narrow host range infecting only two A. baumannii strains. In conclusion, we have isolated and characterized three novel temperate Siphoviridae phages that infect A. baumannii