Springer Online Journal Archives 1860-2000
Summary Eight different species of Trichoderma (T. virgatum, T. longibrachiatum, T. harzianum, T. pseudokoningii, T. polysporum, T. koningii, T. todica, T. saturnisporum), and three strains of T. reesei [QM 6a (wildtype), QM 9123 and QM 9414 (derived mutants)] were found to contain single copies of the cellobiohydrolase genes cbh1 and cbh2 in their genome. This was demonstrated by hybridization of the respective chromosomal DNAs with the corresponding gene fragments of T. reesei QM 9414. According to the relative position of cbh1 and cbh2 in Southern blots, T. harzianum, T. virgatum and T. saturnisporum were clearly distinguishable as unique species. Despite the presence of both cbh genes, these species did not form detectable cellobiohydrolase (CBH) I or II, or exhibit any cellulase activity. All other taxa were identical with respect to the genomic position of cbh1, formed two groups with respect to the position of cbh2, and produced varying amounts of CBH I and II. In all cases CBH I and II production correlated with the relative amount of cbh1- and cbh2-mRNA found. This was particularly true for the three strains of T. reesei, which secreted different amounts of CBH I and II, their efficiency to transcribe cbh1 and cbh2 having been increased as a result of mutation for higher cellulase production.
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