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Research article - Peer-reviewed, 2009

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

Khalil, Sammar; Alsanius, Beatrix

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 *L 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, -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

Keywords

Biolog GN panel; sole carbon source utilisation profiles; hydroponic systems; resident microflora; root pathogens

Published in

Open Microbiology Journal
2009, Volume: 3, pages: 9-14

      SLU Authors

    • Khalil, Samar

      • Horticulture, Swedish University of Agricultural Sciences
    • UKÄ Subject classification

      Horticulture

      Publication identifier

      DOI: https://doi.org/10.2174/1874285800903010009

      Permanent link to this page (URI)

      https://res.slu.se/id/publ/25891