Cellulase formation by species of Trichoderma sect. Longibrachiatum and of Hypocrea spp. with anamorphs referable to Trichoderma sect. Longibrachiatum.
The cellulolytic potential of the wild-type strain of Trichoderma reesei was compared to other members of Trichoderma sect. Longibrachiatum and Hypocrea spp. that have anamorphs referable to that section. There was high diversity even within the same species (as defined by morphological and macromolecular characters). Differences, where notable, were more pronounced for carboxymethyl-cellulase activity than for filter paper activity. High cellulase activities were observed for several strains of T. longibrachiatum and T. citrinoviride, whereas T. parceramosum formed only low levels of activity. Among the corresponding teleomorphs, most strains of H. schweinitzii were comparatively poor producers, whereas the highest percentage of high producers was found among H. jecorina isolates, and many strains were even more active than the parent T. reesei QM 6a. Immunoblot analysis of corresponding culture filtrates of various H. jecorina strains showed that the three major cellulase proteins (cellobiohydrolase I, cellobiohydrolase II, and endoglucanase I) were present in culture filtrates and their M(r) was identical to that of the respective T. reesei proteins. ELISA analysis demonstrated that these enzymes were also present in the same relative proportions in culture filtrates from H. jecorina and T. reesei. With the aid of primers, corresponding to conserved sequences in the cellobiohydrolase I-encoding gene cbh1, a fragment of this gene was amplified from selected strains of H. jecorina, T. reesei, T. longibrachiatum, T. citrinoviride, and H. schweinitzii. The fragments had the same size in all fungi. Cleavage of this fragment with Hhal produced a RFLP pattern which was identical in H. jecorina and T. reesei, but different in the other species. In the latter, the RFLP pattern was also species specific. These results provide support for a close genetic similarity of T. reesei and H. jecorina cellulases. In the latter, an ascomycetous model system for cellulase biosynthesis is now available. The results further indicate that other anamorphs of Trichoderma section Longibrachiatum are promising sources of high cellulase production.
Kubicek
C P
CP
Institut für Biochemische Technologie und Mikrobiologie, TU Wien, Austria. ckubicek@fbch.tuwien.ac.at
Bölzlbauer
U M
UM
Kovacs
W
W
Mach
R L
RL
Kuhls
K
K
Lieckfeldt
E
E
Börner
T
T
Samuels
G J
GJ
D002480:Cellulase / Q000032:analysis / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D002482:Cellulose; D043366:Cellulose 1,4-beta-Cellobiosidase; D005800:Genes, Fungal / Q000235:genetics; D006026:Glycoside Hydrolases / Q000378:metabolism; D006999:Hypocreales / Q000201:enzymology* / Q000235:genetics; D008970:Molecular Weight; D012150:Polymorphism, Restriction Fragment Length; D013045:Species Specificity; D014242:Trichoderma / Q000201:enzymology* / Q000235:genetics
D002482:Cellulose; D006026:Glycoside Hydrolases; D002480:Cellulase; C019826:carboxymethylcellulase; D043366:Cellulose 1,4-beta-Cellobiosidase