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by
P. Rashid Farrokhi |
Total Records (
4 ) for
P. Rashid Farrokhi |
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M. Kalantar Zadeh
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G.H. Shahidi Bonjar
,
P. Rashid Farrokhi
,
A. Ghasemi
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S. Aghighi
and
M.J. Mahdavi
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Streptomyces scabies and S. acidiscabies, the two major phytopathogens induce potato common scab in potato growing areas of Iran. Soil Actinomycetes including 174 isolates were assayed for assessing antagonistic activity against Streptomyces scabies and S. acidiscabies. From tested isolates, S. olivaceus, strain 115 and S. plicatus, strain 101 showed high anti-scab activity revealed by bioassays in agar disk and well diffusion methods. For further biological characterizations, the active strains were grown in submerged cultures to determine growth curve and prepare crude extracts. Preliminary greenhouse studies indicated that amending soil with the S. olivaceus, strain 115 and S. plicatus strain 101 reduce crop losses due to the pathogens. Antibacterial activities of both antagonists were of bactericidal type on both pathogens with complete inhibitory effects. |
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G.H. Shahidi Bonjar
,
S. Zamanian
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S. Aghighi
,
P. Rashid Farrokhi
,
M.J. Mahdavi
and
I. Saadoun
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Ralstonia solanacearum has worldwide economical importance because of its destructive and soil-borne nature. Clearly chemical measures have lost their attractiveness because of development of resistant strains and undesirable effects on our environment. Consequently, biological control of pathogens is gaining great importance worldwide. To investigate for proper biocontrol agents and to obtain antibacterial antagonists from Iranian soil Actinomycetes, a vast survey was performed. Over 170 isolates of soil Actinomycetes were isolated and screened among which one isolate showed high level of activity in Agar disk and Well diffusion methods against R. solanacearum. It was identified as Streptomyces coralus strain 63. High concentration of antibacterial agent was detected at 8-11th day in shake cultures. Longevity in vitro of the active crude in soluble state determined about 40 days at room temperature. In thermal inactivation point studies, active crude retained activity up to 93°C. Antibacterial activity of the antagonists found in this study highlights their importance as candidates for further investigation in biological control of tested pathogenic bacteria. |
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F. Sharifi
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P. Rashid Farrokhi
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G.H. Shahidi Bonjar
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S. Aghighi
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F. Aram
and
E. Khalesi
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Actinomycetes enhance soil fertility and have antagonistic activity against wide range of plant root-pathogens. These micro organisms were isolated from agricultural soils of Kerman and Fars Provinces as pure cultures. Pythium aphanidermatum, causes damping off and root and stem rots of cucurbits worldwide. From 178 Actinomycetes isolates, 43 inhibited growth of the pathogen in culture plates and two of the most active isolates exhibited biological control of the pathogen under greenhouse conditions. When plants were grown in sterile soil mix and treated both with Actinomycetes and the pathogen, the number of healthy plants increased dramatically and the symptoms on diseased plants were less severe in comparison with seedlings treated with the pathogen alone. From the collected data it was well conclusive that in greenhouse tests, soil applications of Actinomycetes controlled causal agent of damping off in cucurbit seedlings. Antifungal activity was of fungicidal type on the pathogen mycelia. Regarding biotechnological implications, the results indicate that the active isolates can be investigated for use as biofertilizers, biofungicides and use in future development of recombinant DNA in cucurbits bearing elevated resistance to damping off. Field trials of the active isolates are under investigation. |
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F. Sharifi
,
G.H. Shahidi Bonjar
,
S. Aghighi
,
P. Rashid Farrokhi
,
E. Khalesi
,
M.J. Mahdavi
and
H. Taraz
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Pythium aphanidermatum, the major phytopathogen induce damping off, root and stem rots, blights of grasses and fruit and in greenhouse cucurbits growing all areas of the world. Soil Actinomycetes including 178 isolates were assayed for assessing antagonistic activity against P.aphanidermatum. From tested isolates, 43 isolates were effective but 2 isolates strains 311 and 321 showed high anti-fungal activity revealed by bioassays in agar disk and well diffusion methods. For further biological characterizations, the active strains were grown in submerged cultures to determine growth curve and prepare crude extracts. Preliminary greenhouse studies indicated that amending soil with these strains, 311 and 321; reduce crop losses due to the pathogen. Antifungal activities of both antagonists were of fungicidal type on pathogen with complete inhibitory effects.
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