Biochemical characterization of biocontrol agents used for control of root pathogens.
Due to low microbial biodiversity in the nutrient solution and the root, open and closed hydroponic systems are regarded as sensitive from biological point of view. This is of particular importance as an enhanced spread of root pathogen may occur in closed hydroponic systems and possibilities for chemical control are restricted. Biocontrol agents appear to be a feasible alternative. For an effective use of these agents, knowledge on the behaviour, external requirements and the specific capabilities of such agents is needed. The aim of this survey was to describe properties of Trichoderma polysporum and Trichoderma harzianum, Gliocaldium cantenulatum and Streptomyces griseoviridis, the active ingredients in the commercial products BinabT, Gliomix and Mycostop, respectively by biochemical methods using sole carbon source utilization (SCSU) patterns. Two-week-old cultures of the individual active compound in BinabT, Gliomix and Mycostop were inoculated on Microlog GN2 panel with ten replicates and incubated for 240 h with repeated computer-assisted spectrophotometrical readings. On the bases of the average well color development (AWCD), separation on the utilization patterns was noticed after 72 h of incubation for the biocontrol agents in Binab T, while 60 h and 36 h were the times noticed for the biocontol agents in the Gliomix and Mycostop products, respectively. Carbon source utilization by the active compound of Mycostop was uniform during the first 96 h of inoculation, but varied substantially during the following reading incidents. For Trichoderma polysporum and Trichoderma harzianum 50 sole carbon sources were utilized among these dextrin, i erythritol, gentiobiose, fructose and glycerol. Around 30 sole carbon sources were utilized by Gliocaldium cantenulatum. Sucrose, Trehalose, Adonitol, L-araninose, malonic acid and D,L Lactic acid are some of these. D-glucuronic acid, D, galactose, D-mannitol, citric acid, uridine, L-alanine and D-serin are some of the carbon sources that were utilized by Streptomyces griseoviridis.
Khalil
S
S
Department of Crop Science, Div. of Horticulture, Horticultural Microbiology& Biocontrol Group, P.O. Box 44, SE-230 53 Alnarp, Sweden. sammar.khalil@vv.slu.se
Alsanius
B W
BW
D010572:Pest Control, Biological / Q000379:methods*; D010935:Plant Diseases / Q000382:microbiology*; D018517:Plant Roots / Q000382:microbiology*; D013302:Streptomyces / Q000472:pathogenicity; D014242:Trichoderma / Q000472:pathogenicity*