Cell wall degradation of Fusarium oxysporum f.sp. lycopersici race 2 by lytic enzymes from different Fusarium species for its biocontrol

Comparative studies on the induction of Trichoderma harzianum mutanase by α-(1→3)-glucan-rich fruiting bodies and mycelia of Laetiporus sulphureus

Mutanase (α-(1→3)-glucanase) is a little-known inductive enzyme that is potentially useful in dentistry. Here, it was shown that the cell wall preparation (CWP) obtained from the fruiting body or vegetative mycelium of polypore fungus Laetiporus sulphureus is rich in α-(1→3)-glucan and can be successfully used for mutanase induction in Trichoderma harzianum. The content of this biopolymer in the CWP depended on the age of fruiting bodies and increased along with their maturation. In the case of CWP prepared from vegetative mycelia, the amount of α-(1→3)-glucan depended on the mycelium age and also on the kind of medium used for its cultivation. All CWPs prepared from the individually harvested fruiting body specimens induced high mutanase activity (0.53–0.82 U/mL) in T. harzianum after 3 days of cultivation. As for the CWPs obtained from the hyphal mycelia of L. sulpureus, the maximal enzyme productivity (0.34 U/mL after 3 days of incubation) was recorded for CWP prepared from the 3 week-old mycelium cultivated in Sabouraud medium. Statistically, a high positive correlation was found between the total percentage content of α-(1→3)-glucan in the CWP and the mutanase activity.

Hydrolysis of fungal and plant cell walls by enzymatic complexes from cultures of Fusarium isolates with different aggressiveness to rye (Secale cereale)

The efficiency of hydrolysis of fungal (Fusarium spp.) cell wall and rye root cell wall by crude enzymatic complexes from (42-day-old) cultures of three F. culmorum isolates, a plant growth-promoting rhizosphere isolate (PGPF) DEMFc2, a deleterious rhizosphere isolate (DRMO) DEMFc5, and a pathogenic isolate DEMFc37, as well as two other, pathogenic isolates belonging to F. oxysporum and F. graminearum species was studied. In the enzymatic complexes originating from the Fusarium spp. cultures, the activities of the following cell wall-degrading enzymes were identified: glucanases, chitinases, xylanases, endocellulases, exocellulases, pectinases, and polygalacturonases. The preparation originating from a culture of the PGPF isolate was the least efficient in plant cell wall (PCW) hydrolysis. There were no significant differences in the efficiency of PCW hydrolysis between preparations from cultures of the DRMO and the pathogenic isolates. PGPF was the most efficient in liberating reducing sugars and N-acetylglucosamine (GlcNAc) from fungal cell walls (FCW). Xylanase activities of the enzymatic complexes were strongly positively (R > +0.9) correlated with their efficiency in hydrolyzing PCW, whereas chitinase activities were correlated with the efficiency in FCW hydrolysis.