The influence of mineral and carbon sources on biological control of charcoal rot fungus, Macrophomina phaseolina by fluorescent pseudomonads in tomato.
OBJECTIVE
To determine the influence of various trace minerals and carbon source on the biocontrol performance of Pseudomonas aeruginosa strain IE-6S+ and P. fluorescens strain CHA0 against Macrophomina phaseolina.


RESULTS
In dual culture plate assay, P. aeruginosa IE-6S+ and P. fluorescens CHA0 inhibited radial growth of M. phaseolina producing zones of inhibition. Czapek's dox agar medium amended with both zinc and glucose remarkably improved antifungal activities of the bacterial inoculants. Under glasshouse conditions, soil amendment with zinc and/or glucose alone did not reduce M. phaseolina infection in tomato roots but did reduce significantly when used in combination with IE-6S+ or CHA0. Soil amendments with zinc and/or glucose increased fresh shoot weights but zinc amendment greatly reduced bacterial populations in the rhizosphere.


CONCLUSIONS
Mineral and carbon amendments enhance the biocontrol performance of fluorescent pseudomonads against M. phaseolina.


CONCLUSIONS
Identification of mineral and carbon amendments that favour biocontrol of certain bacterial strains may provide clues to soil factors or components of nutrient solutions in hydroponic culture that will improve the level and reliability of control.
Shaukat
S S
SS
Soil Biology and Ecology Laboratory, Department of Botany, University of Karachi, Karachi, Pakistan. imran_75850@yahoo.com
Siddiqui
I A
IA
D000898:Antibiosis; D001487:Basidiomycota / Q000254:growth & development*; D002244:Carbon / Q000378:metabolism*; D003470:Culture Media; D005947:Glucose / Q000378:metabolism; D018551:Solanum lycopersicum / Q000382:microbiology; D010572:Pest Control, Biological; D010935:Plant Diseases / Q000382:microbiology; D018517:Plant Roots / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000254:growth & development*; D011551:Pseudomonas fluorescens / Q000254:growth & development*; D014131:Trace Elements / Q000378:metabolism*; D015032:Zinc / Q000378:metabolism
D003470:Culture Media; D014131:Trace Elements; D002244:Carbon; D005947:Glucose; D015032:Zinc