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Research Journal of Microbiology
  Year: 2012 | Volume: 7 | Issue: 2 | Page No.: 82-100
DOI: 10.3923/jm.2012.82.100
 
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Materials for Pythium Flora of Saudi Arabia (I) Occurrence, Pathogenicity and Physiology of Reproduction of Pythium aphanidermatum (Edson) Fitzp. Isolated from North and East Regions of Saudi Arabia

Hashem Al-Sheikh and Hani M.A. Abdelzaher

Abstract:
Increase the productivity of crops is a matter of concern for workers in the field of crop science and plant diseases. Pythiaceous fungi are one of the biggest sources of injury to seedling crop plants, especially if environmental conditions were not favorable for plant growth and favorable for the disease prevalence. Seventy four isolates of virulent Pythium aphanidermatum were obtained from rhizosphere soil of maize, potato, tomato and wheat plants cultivated in five farms in Al-Jouf and a farm in Al-Hassa, Saudi Arabia. Sequencing of rDNA-ITS of the isolated P. aphanidermatum including the 5.8SrDNA were analyzed to confirm the species identification. Isolates of P. aphanidermatum started to produce zoospores after 72 h incubation at 20, 25, 30, 35 and 40°C. Production of zoospores was inhibited at pH 4 and prompted within the pH range 5-8 with optimum at pH 7. All isolates were able to produce zoospores between -0.13 to -0.27 MPa but not above this range. The highest zoospore production was found at -0.27 MPa but it was inhibited by 0.5% NaCl. The optimum concentrations for zoospores production were between 0.1 and 0.2% gm NaCl. Oospores produced between 10°C and 45°C but not at 50°C. Optimum temperatures for oospores production were between 30-35°C. Oospores production happened over a range of pH 5-9 with Optimum values between 6.5-7.5. Oospores produced at -0.13 to -1.65 MPa osmotic potentials with the optimum production rate at -0.27 to -0.47 MPa. Oospores produced at 0.1-1% NaCl with the optimum production rate at 0.3-0.4%.
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How to cite this article:

Hashem Al-Sheikh and Hani M.A. Abdelzaher, 2012. Materials for Pythium Flora of Saudi Arabia (I) Occurrence, Pathogenicity and Physiology of Reproduction of Pythium aphanidermatum (Edson) Fitzp. Isolated from North and East Regions of Saudi Arabia. Research Journal of Microbiology, 7: 82-100.

DOI: 10.3923/jm.2012.82.100

URL: https://scialert.net/abstract/?doi=jm.2012.82.100

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