10th INTERNATIONAL VERTICILLIUM SYMPOSIUM 16-20 ...

MODE OF ACTION OF A NON-PATHOGENIC FUSARIUMOXYSPORUM STRAIN AGAINST VERTICILLIUM DAHLIAEI.S. PANTELIDES 1 , TJAMOS 1 S.E., I. STRIGLIS 1 , I. CHATZIPAVLIDIS 2 , E.J.PAPLOMATAS 11 Department of Plant Pathology and ,2 Laboratory of General and Agricultural Microbiology,Agricultural University of Athens, 75 Iera Odos, 118 55 Athens, GreeceNumerous studies have examined the interaction of various non-pathogenicFusarium oxysporum strains with different pathogenic formae speciales of F.oxysporum; however, there were no reports until recently about non-pathogenic F.oxysporum strains having a suppressive effect on Verticillium dahliae. In 2008, wereported the efficacy of a non-pathogenic Fusarium oxysporum strain, designated asF2, isolated from a suppressive compost amendment, to reduce Verticillium wiltsymptom development in eggplants under greenhouse and field conditions; inaddition, antibiosis or parasitism were ruled out by using a dual culture test. In thepresent study, the mode of action of F2 against V. dahliae was investigated. For thispurpose, the F2 and V. dahliae strains were transformed with the EGFP and DsRed2reporter genes, respectively, to facilitate visualization of their presence on eggplantsroot surface. In addition, the ramification of both fungi into the plant vascular systemwas monitored by Real Time qPCR analysis. It was shown that F2 colonizes the rootsurface along the intercellular junctions excluding V. dahliae from the sameecological niche. In parallel, qPCR analysis showed that application of F2 reduces thelevels of V. dahliae vascular colonization along with the disease severity. In a splitroot experiment it was demonstrated that F2 does not trigger the defense mechanismsof eggplants against V. dahliae. Therefore, it seems that competition for space ornutrients on the root surface are the main mechanisms of action of F2 against V.dahliae.84