Purification and characterization of an endo-beta-1,6-glucanase from Trichoderma harzianum that is related to its mycoparasitism

Abstract

The enzymes from Trichoderma species that degrade fungal cell walls have been suggested to play an important role in mycoparasitic action against fungal plant pathogens. The mycoparasite Trichoderma harzianum produces at least two extracellular ␤-1,6-glucanases, among other hydrolases, when it is grown on chitin as the sole carbon source. One of these extracellular enzymes was purified to homogeneity after adsorption to its substrate, pustulan, chromatofocusing, and, finally, gel filtration. The apparent molecular mass was 43,000, and the isoelectric point was 5.8. The first 15 amino acids from the N terminus of the purified protein have been sequenced. The enzyme was specific for ␤-1,6 linkages and showed an endolytic mode of action on pustulan. Further characterization indicated that the enzyme by itself releases soluble sugars and produces hydrolytic halli on yeast cell walls. When combined with other T. harzianum cell wall-degrading enzymes such as ␤-1,3-glucanases and chitinases, it hydrolyzes filamentous fungal cell walls. The enzyme acts cooperatively with the latter enzymes, inhibiting the growth of the fungi tested. Antibodies against the purified protein also indicated that the two identified ␤-1,6-glucanases are not immunologically related and are probably encoded by two different genes.

Characterization of an Exo-β-1,3-Glucanase Produced by Pichia anomala Strain K, Antagonist of Botrytis cinerea on Apples

“…Our findings are similar to those obtained with Saccharomyces cerevisiae and T. harzianum, which also produced both endo-and exo-β-1,3-glucanases (10,18,24). Our findings are similar to those obtained with Saccharomyces cerevisiae and T. harzianum, which also produced both endo-and exo-β-1,3-glucanases (10,18,24).…”

Enhanced fungal resistance in transgenic cotton expressing an endochitinase gene from Trichoderma virens

“…is due to the presence of hydrolytic enzymes, including chitinases (Carsolio et al, 1999;De La Cruz et al, 1995;Flores et al, 1997;Peterbauer et al, 1996;Thrane et al, 1997). Hadar et al (1979) showed that T. harzianum, under greenhouse conditions, when applied in the form of wheat bran culture to R. solani-infested soil, effectively controlled damping-off in bean, tomato and eggplant seedlings.…”

The pitch canker fungus,Fusarium circinatum: implications for South African forestry

“…The most commonly reported biocontrol agents are species of Trichoderma (Bell et al 1982, Ordentlich et al 1991, of which T. harzianum is reported to be especially effective (de la Cruze et. al.…”