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Search for "abdel-hafez s.": 2 articles found.
ABDEL-HAFEZ S.I.I., ABO-ELYOUSR K.A.M., ABDEL-RAHIM I.R. (2015): Leaf surface and endophytic fungi associated with onion leaves and their antagonistic activity against Alternaria porri. [phyllosphere, phylloplane, endophytes, purple blotch disease, antagonism] Czech Mycology 67(1): 1-22 (published: 10th April, 2015)
abstract
Sixty-eight fungal species belonging to 29 genera were isolated as leaf surface and endophytic fungi from healthy and purple blotch diseased onion leaves. The fungal populations associated with diseased onion leaves (1.360 × 103 CFU/g leaf in the phyllosphere, 2.614 CFU/leaf segment in the phylloplane and 1.324 CFU/leaf segment in the surface-sterilised diseased leaves) were higher than those in healthy samples (0.804 × 103 CFU in the phyllosphere, 1.184 CFU in the phylloplane, and 0.35 CFU as endophytes). Endophytic fungi of healthy leaves were represented by 12 genera and 15 species, while fungi of surface-sterilised diseased leaves included 17 species from 13 genera. The mycobiota associated with surface-sterilised diseased leaves were different from the endophytic fungi of healthy samples, whereas the disease may stimulate colonisation of opportunistic fungi causing secondary infections such as Botrytis cinerea, Penicillium aurantiogriseum, Alternaria alternata and Cladosporium spp. In contrast, healthy leaves were a source of antagonistic endophytic fungi such as Trichoderma harzianum and T. koningii. Testing the antagonistic effect of 91 fungal isolates against Alternaria porri showed that nine isolates of Trichoderma produced the highest suppressive potential (73.1%) depending on competition and mycoparasitism. Epicoccum nigrum and Penicillium oxalicum exhibited antibiosis against A. porri producing a 12 mm broad inhibition zone. In conclusion, the quantitative and qualitative compositions of fungi associated with onion leaves were distinctly influenced by A. porri infection. Mycobiota associated with asymptomatic onion leaves such as Epicoccum nigrum, Penicillium oxalicum and Trichoderma harzianum are a natural source of eco-friendly bioagents. They showed an effective antagonistic potential against A. porri, and may thus be applied as an alternative to fungicides.
ISMAIL M.A., ABDEL-HAFEZ S.I.I., HUSSEIN N.A., ABDEL-HAMEED N.A. (2013): Contribution to physiological and biochemical diagnostics of Fusarium taxa commonly isolated in Egypt. [Fusarium, taxonomy, physiological features, acetylmethylcarbinol, diagnostic] Czech Mycology 65(1): 133-150 (published: 10th June, 2013)
abstract
Fusarium isolates belonging to 24 species and 8 sections were subjected to 11 growth, physiological and biochemical tests (166 isolates). All species were able to grow on 25% Glycerol nitrate agar (G25N), Mannitol medium, Czapek iprodione dichloran agar (CZID) and Dichloran chloramphenicol peptone agar (DCPA). Growth rate, colony colour and reverse on G25N and CZID were promising diagnostic criteria for separating species within sections. The growth rate and reverse on Mannitol agar was diagnostic not only for separation of F. oxysporum from F. solani, but also for separation of many other Fusarium species treated. The ability to grow on Tannin-sucrose agar could distinguish some species of sections Liseola and Sporotrichiella. Acid production on Creatine-sucrose agar distinguished some species of section Liseola and F. trichothecioides of section Discolor. Acetylmethylcarbinol production revealed for the first time that all isolates of F. subglutinans can produce this substance, while most remaining isolates lacked this ability. Tests for peroxidase, urease and pyrocatechol oxidase proved to be very useful. The phosphatase enzyme seems to be common in Fusarium species and therefore it is only diagnostic for F. camptoceras (negative results). Some physiological features could be used as criteria to distinguish some sections or species within the same section.
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