A total of 36 UV-induced mutants with altered colony morphology were isolated from strain
T334, a potential biocontrol agent against plant pathogenic fungi with the ability to produce constitutively low levels of chitinases. The level of constitutive
-acetyl-glucosaminidase production in standing and shaken cultures under non-inductive conditions was tested in mutants and compared to that of the parental strain. About 30% of the mutants showed significantly increased levels of enzyme production, with strain T334 col26a being the best producer. This mutant and the parental strain were subjected to
confrontation assays with plant pathogenic
Fusarium culmorum, Pythium debaryanum
strains. The mutant derivative could be characterized by significantly higher biocontrol index values than the parental strain in each experiment, suggesting, that mutants with improved constitutive extracellular chitinase secretion could be applied for biocontrol purposes against fungal plant pathogens.