Study of the interaction of Vertidllium dahliae with the non-pathogenic isolate Fusarium oxyspo rum F2

Verticillium wilt is a devastating disease of a wide range of herbaceous and woody plant hosts, incited by the soilborne fungus Verticillium dahliae. Since there are no chemical treatments to control the pathogen, management strategies are focused on preventive measures. Along these lines, the use of biocontrol agents has been evaluated as an alternative to control V. dahliae. In the present study it was investigated the mode of action of the non pathogenic isolate Fusarium oxysporum F2 against V.dahliae. The non pathogenic isolate Fusarium oxysporum F2 has been isolated from a suppressive compost amendment and its sup-pressive action against V.dahliae 'has been reported in a previous study. It was shown that the ability of strain F2 to protect eggplants against V. dahliae is a dose-response effect. On the other hand, the strain F2 did not trigger the induction of systemic resistance in eggplants against V.dahliae in a split root system. Strain F2 was transformed with the eGFP gene and V. dahliae was transformed with the DsRed2 fluorescent gene to facilitate monitoring of the simultaneous colonisation of the eggplants root system by both the antagonist and the pathogen. It was demonstrated that the reported efficacy of strain F2 against V. dahliae can be attributed to the phenomenon of competition for site on the root system.