Evaluation of production of some antifungal metabolites by fluorescent pseudomonads in vitro and their inhibitory effect on Penicillium digitatum in semi-commercial condition
Zamani, M.; Sharifi Tehrani, A.; Ahmadzadeh, M.; Ali Abadi, A.A.
Communications in Agricultural and Applied Biological Sciences 72(4): 935-939
2007
ISSN/ISBN: 1379-1176 PMID: 18396831 Document Number: 606269
Epiphytic fluorescent Pseudomonads isolated from the surfaces of citrus leaves and fruits collected from the citrus orchards located in the north of Iran were screened for antagonistic activity against Penicillium digitatum caused agent of green mold of citrus fruit. 9 isolates revealed antagonistic effect in dual culture and then evaluated for production of antimicrobial metabolites such as production hydrogen cyanide on King's B medium containing glycine, production of siderophore on blue CAS-agar medium and production protease enzyme on Skim Milk Agar (SMA) medium. About 28% strains produced hydrogen cyanide, 83% strains produced siderophore and 70% of them produced protease. Antagonistic effects of the screened 9 isolates were studied by inoculating of the infected orange fruits with the bacterium at the concentration of 10(8) cells/ml under sterilized condition at 20 degrees C. The three final screened antagonist isolates were more studied in semi commercial trails in cold storage with dipping of the orange fruits in the bacterial suspension at the concentration of 10(8) cells/ml and then 5 weeks storage at 4 degrees C. The isolate P39 showed to be the most effective for controlling of this disease and decreased the damage by 77.28% respectively.