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Utilisation of Carbon Sources by Pythium, Phytophthora and Fusarium Species as Determined by Biolog® Microplate Assay

By Sammar Khalil and Beatrix W Alsanius

Abstract

This study examined the metabolic activity of pure cultures of five root pathogens commonly found in closed hydroponic cultivation systems (Phytophthora cryptogea (PC), Phytophthora capsici (PCP), Pythium aphanidermatum (PA), Fusarium oxysporum f.sp. radicis-lycopersici (FORL) and Fusarium solani (FS)) using sole carbon source utilisation in order to develop effective biocontrol strategies against these pathogens. Aliquots of 150 µL of the mycelial suspension were inoculated in each well of GN2 microtitre plates. On the basis of average well colour development and number of positive wells, the pathogens were divided into two groups, (i) PA and FORL and (ii) PC, PCP and FS. Group (i) was characterised by a short lag-phase, a rapid exponential phase involving almost all carbon sources offered and a long stationary phase, while group (ii) had a more extended lag-phase and a slower utilisation rate of the carbon sources offered. The three isolates in group (ii) differed significantly during their exponential phase. The lowest utilisation rate of carbon sources and number of sources utilised was found for PCP. Of the major group of carbon sources, six carbohydrates, three carboxylic acids and four amino acids were rapidly used by all isolates tested at an early stage. The carbon sources gentibiose, α-D-glucose, maltose, sucrose, D-trehalose, L-aspartic acid, L-glutamic acid, L-proline persisted to the end of the exponential phase.Moreover, similarities between the metabolic profiles of the tested pathogen and the those of the resident microflora could also be found. These findings are of great importance as regards the role of the resident microflora in the biocontrol

Topics: Article
Publisher: Bentham Open
OAI identifier: oai:pubmedcentral.nih.gov:2656775
Provided by: PubMed Central
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    Citations

    1. (2001). A comparison of sole carbon source utilization patterns and phospholipid fatty acid profiles to detect changes in the root microflora of hydroponically grown crops.
    2. (1998). Analysis of BIOLOG GN substrate utilization patterns by microbial communities. Appl Environ Microbiol
    3. (1998). Biochemical and chemical characterization of Pythium ultimum. Meded Fak Landboukwd Toegep Biol Wet Univ
    4. (2006). Biochemical characterization of biocontrol agents used for control of root pathogens.
    5. (2003). Chung Ill-M. Determination of carbon source utilization of Bacillus and Pythium species by Biolog® microplate assay.
    6. (1991). Classification and Characterization of Heterotrophic Microbial Communities on the Basis of Patterns of Community-Level Sole-Carbon-Source Utilization. Appl Environ Microbiol
    7. (2001). Disinfection of recirculating nutrient solution in greenhouse horticulture. Agronomy
    8. (2001). Dynamics of the indigenous microflora inhabiting the root zone and the nutrient solution in a commercial closed greenhouse system. Gartenbauwiss
    9. (1958). Effect of carbon sources upon the mycelial growth and sporulation of the fungus Phytophthora capsici Leonian. Scientific reports of the Saikyo University Agriculture,
    10. (1977). Generalized indicator plate for genetic, metabolic and taxonomic studies of microorganisms.
    11. (1994). Hydroponics- a solution for zoosporicpathogens. Plant Dis
    12. (1993). Influence of carbon source on attachment and germination of macroconidia of Fusarium solani f.sp. phaseoli on roots of Vigna radiate grown in hydroponic nutrient solution. Plant Dis
    13. (2002). Microflora in the root environment of hydroponically grown tomato: Methods for assessment and effects of introduced bacteria and Pythium ultimu. Thesis, Alnarp: Swedish University of Agricultural Sciences. Acta Universitatis Agriculturae Sueciae,
    14. (1992). Nutritional and environmental factors affecting biomass oospore production of the biocontrol agent Pythium oligandrum. Enzyme Microb Technol
    15. (2004). Potential of utilization of selected organic compounds by the microflora inhabiting the effluent nutrient solution of closed greenhouse irrigation systems.

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