Zinc and glycerol enhance the production of nematicidal compounds in vitro and improve the biocontrol of Meloidogyne javanica in tomato by fluorescent pseudomonads.
OBJECTIVE
To assess the effects of various carbon and mineral sources on the nematicidal potential of biocontrol inoculants of Pseudomonas aeruginosa IE-6S+ and Ps. fluorescens CHA0 under laboratory and glasshouse conditions.


RESULTS
Culture filtrates of strains IE-6S+ and CHA0, cultured in nutrient yeast extract broth, caused substantial mortality of the juveniles of Meloidogyne javanica. The nematicidal activities of the culture filtrates were altered after amendment with various carbon and mineral sources. Soil amendment with zinc alone or in combination with glycerol improved the biocontrol efficacy against root-knot nematode, promoted tomato plant growth and enhanced bacterial rhizosphere and endophytic colonization.


CONCLUSIONS
Appropriate quantities of glycerol and zinc alone or in combination enhance the nematicidal activity of Ps. aeruginosa and Ps. fluorescens. Glucose reduces the activity of these bacteria against nematodes.


CONCLUSIONS
Minerals and carbon sources are appealing because they are easy and economical to provide during liquid fermentation of inoculants or as fertilizer amendments to improve the biocontrol activity of indigenous and introduced bacteria.
Siddiqui
I A
IA
Soil Biology and Ecology Laboratory, Department of Botany, University of Karachi, Karachi, Pakistan. imran_75850@yahoo.com
Shaukat
S S
SS
D000818:Animals; D000871:Anthelmintics / Q000378:metabolism / Q000494:pharmacology; D003470:Culture Media; D005990:Glycerol / Q000378:metabolism / Q000494:pharmacology; D018551:Solanum lycopersicum / Q000469:parasitology*; D010572:Pest Control, Biological; D010935:Plant Diseases / Q000469:parasitology; D011549:Pseudomonas / Q000254:growth & development / Q000378:metabolism*; D011550:Pseudomonas aeruginosa / Q000254:growth & development / Q000378:metabolism; D011551:Pseudomonas fluorescens / Q000254:growth & development / Q000378:metabolism; D014431:Tylenchoidea / Q000187:drug effects / Q000254:growth & development*; D015032:Zinc / Q000378:metabolism / Q000494:pharmacology
D000871:Anthelmintics; D003470:Culture Media; D015032:Zinc; D005990:Glycerol