Carbon adaptation influence the antagonistic ability of Pseudomonas aeruginosa against Fusarium oxysporum f. sp. melonis

Influences of carbon adaptation on antagonistic activities of three Pseudomonas aeruginosa strains V 4 , V 7 and V 10 against Fusarium oxysporum f. sp. melonis were determined in this study. Results from this study showed that the P. aeruginosa strains and their adapted strains significantly inhibited the growth of mycelium of F. oxysporum f. sp. Melonis, while in vitro inhibition of P. aeruginosa on the mycelial growth was unaffected by carbon adaptation. In general, the growth of strain V 4 and its antagonistic ability was unaffected by carbon adaptation. However, the growth of the adapted strains V 7 -C and V 10 -C was superior to the corresponding parental strains when root exudates were used as a sole carbon source. In addition, the adapted strains V 7 -C and V 10 -C caused a more decrease in Fusarium infection of melon compared with the corresponding parental strains. Overall, this study revealed that adaptation culture of P. aeruginosa strains on carbon-limited media may play an important role in the inhibition of Fusarium wilt of melon seedlings although the effect of carbon adaptation may depend on the test strain. Key words: Melon, biocontrol, Fusarium wilt, in vitro, in vivo.