A novel method for the identification and enumeration of microorganisms with potential for suppressing fungal plant pathogens

Rupela, O P and Gopalakrishnan, S and Krajewski, M and Sriveni, M (2003) A novel method for the identification and enumeration of microorganisms with potential for suppressing fungal plant pathogens. Biology and Fertility of Soils, 39. pp. 131-134.

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This paper describes a method that allowed counting of both the total culturable and antagonistic microorganisms in a given source such as compost. Fusarium solani, used as the test fungus, was spreadplated on quarter-strength (1/4) potato dextrose agar (PDA), its surface was exposed in a laminar flow for 4 h and then another layer (2–3 mm thick) of 1/4 PDA was poured over it, on which an appropriate dilution of a compost sample was spread-plated. Microorganisms in the compost samples appeared first, and were counted as total culturable organisms. Plates were further incubated until F. solani grew through the upper layer of PDA (generally in 4–8 days) and covered the whole plate including most of the microbial colonies, except for a few which had a halo around them. These were counted as antagonistic, and they were isolated and purified for further studies. The population of bacteria in the six specific compost samples (called Biodynamic or BD preparations by organic farmers) ranged from 3.45 log10 (in BD502) to 8.59 log10 (in BD504) per gram of materials. The population of antagonistic bacteria was counted for three of the six compost samples, and ranged from 3.24 log10 (in BD502) to 6.90 log10 (in BD500). Of the 67 bacterial isolates showing a halo that were assembled from different sources, 17 suppressed at least 1 of the 4 plant pathogenic fungi against which these were evaluated using the dual culture method.

Item Type: Article
Subjects: Others > Agriculture-Farming, Production, Technology, Economics
Depositing User: Library ICRISAT
Date Deposited: 12 Sep 2011 06:51
Last Modified: 12 Sep 2011 06:51
URI: http://oar.icrisat.org/id/eprint/1322
Official URL: http://dx.doi.org/10.1007/s00374-003-0680-8
Acknowledgement: We thank Drs S.D. Singh and R.P. Thakur for providing the fungal cultures used in the study, Dr S. Chandra for verification of statistical aspects; and all of them plus Dr P. Tauro, Professor Emeritus, Mangalore, India for comments on the manuscript. We also thank Mr S.S. Navi, ICRISAT, for help with the microscopic studies
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