Trichoderma isolates from vegetable rhizosphere samples : potential for the biological control of botrytis species

Abstract

Members of the genus Trichoderma are wide-spread saprophytic fungi living in the soil and the rhizosphere
of different plants. Due to their enzyme production abilities they are able to use complex biomolecules as
carbon and nitrogen source. Many strains with very good biocontrol abilities against plant pathogenic fungi
could be isolated from soils of agricultural areas. In this study we isolated Trichoderma strains from the
rhizosphere of vegetables (pepper and lettuce) derived from gardens of different Hungarian cities (Szolnok,
Kalocsa, Újszilvás, Kelebia). The isolates were identified by the sequence analysis of the ITS (internal
transcribed spacer) region. The strains belonging to species that are not pathogenic to humans or cultivated
mushrooms and possessing promising bicontrol potential were further investigated. The antagonistic abilities
of the strains were studied against Botrytis species (B. cinerea, B. pseudocinerea) in in vitro confrontation
tests and the extracellular enzyme systems of the strains were investigated in different liquid media. The
knowledge of the correlation between the in vitro antagonistic abilities and enzyme production may
contribute to our understanding of the biocontrol mechanism.