Plant responses during the pathogen infection and the pathogen control reflect its strategies to protect its cells. This work represents the Alternaria cerealis MT808477 as a phytopathogen causing leaf spot disease in tomatoes. A. cerealis was identified morphologically and genetically by 18SrRNA, and its pathogenicity was confirmed by light and scanning electron microscopy. Trichoderma harzianum has the ability to control A. cerealis MT808477 by stimulating various cell responses during the controlling process. The cell behavior during the biological control process was observed by analyses of total phenol, flavonoids, terpenoids, antioxidant, malondialdehyde and antioxidant enzymes (catalase and peroxidase). The extracts of infected tomato leaves were tested against plant and human pathogenic microorganisms. Results showed that the biological control process activates the defense cell strategies by increasing the plant tolerance, and activation of plant defense systems. The total phenol, flavonoids, terpenoids, antioxidant and malondialdehyde were increased after 48 h. Catalase and peroxidase were increased in infected tomato plants and decreased during the biological control process, reflecting the decrease of cell stress. Leaves extract inhibited the growth of nine plant and human pathogenic microorganisms. Biological control represents a safe and effective solution to phytopathogens that decreases plant cell stress by stimulating various defensive agents.
Pollen morphology of ten members of cruciferae growing in Egypt are studied. Two categories of exine sculpture are recognized: reticulate and microreticulate. Pollen shape and size as well as exine sculpture are proved to be of major taxonomic value. Description of the examined pollen are also included.
Sixty‐one species and one variety belonging to 24 genera were collected from pollen grains and anthers of examined plants on glucose Czapek‐Dox agar at 28 °C. The widest spectrum of genera and species were found in subprolate, microreticulate pollen and anthers of Erucaria hispanica (12 genera, 29 species) and the lowest in prolate spheroidal reticulate pollen and anthers of Farsetia aegyptia (6 genera, 12 species). Results revealed that there is no specific fungal spores were restricted to pollen shape of the studied taxa. The most frequently encountered fungi in pollen and anthers of most tested plants were: Alternaria alternata, Pleospora herbarum, Aspergillus flavus, A. fumigatus, A. terreus, Cladosporium cladosporioides, C. sphaerospermum, Penicillium chrysogenum and P. oxalicum. Some fungi were common only on pollen grains and anthers of one plant such as Fusarium oxysporum on Erucaria hispanica, Nectria haematococca on Eruca sativa and Ulocladium botrytis on Diplotaxis muralis.
During a survey of phyllosphere and non-rhizosphere soil fungi of orange plantations in the Assiut area, Egypt, several isolates of species of Aspergillus belonging to the section Usti were isolated at 25°C. These were identified using phenotypic and genotypic characters as Aspergillus porphyreostipitatus and Aspergillus carlsbadensis. To the best of our knowledge, these are the first global records since their original descriptions and indicate their probable wide distribution. The strains of both species could grow at 37°C (a character contrasting to that of the original description of A. carlsbadensis), but both were not able to grow on CYA at 5°C or 45°C or to produce acid on creatine. It is interesting to report that both strains produced the urease enzyme (however weakly in A. porphyreostipitatus) and failed to grow on G25N at 25°C, characters not examined in the original descriptions.
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