Abstract

Influences of carbon adaptation on antagonistic activities of three Pseudomonasaeruginosa strains V₄, V₇ and V₁₀ against Fusarium oxysporum f. sp. melonis weredetermined in this study. Results from this study showed that the P. aeruginosastrains 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 V₄ and its antagonistic ability was unaffected by carbon adaptation. However, the growth of the adapted strains V₇-C and V₁₀-C was superior to the corresponding parental strains when root exudates were used as a sole carbon source. In addition, the adapted strains V₇-C and V₁₀-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.

Abbreviation

FOM, Fusarium oxysporum f. sp. melonis; KMB, King's medium B; NA, nutrient agar; MM, minimal medium; NB, nutrient broth; PDA, potato dextrose agar.