STUDY ON INDUCTION OF TRICHODERMA LONGIBRACHIATUM

Abstract

Trichoderma species are known as potential biocontrol agents against the plant pathogenic fungi with various mechanisms (parasitism, antibiosis, substrate competition...). One of the most important mechanisms is the secretion of cell wall degrading enzymes. Chitinolytic enzymes, especially, endochitinase plays an important role in the enzymatic mechanism by the abundant and frequent induction more than other groups in whole of chitinolytic system. Trichoderma longibrachiatum TÐ16 was grown in the TSM medium containing various substrates. We recognized that 1.0% (w/v) colloidal chitin and 0.5% (w/v) S. rolfsii cell wall induced to biosynthesize chitinase and endochitnase with higher activity than P. capsici cell wall at the fifth day. This strain induced and expressed various endochitinase isozymes when growing on the substrates above, respectively. Two endochitnase isozymes (52 and 42 kDa) on colloidal chitin and (42 and 36 kDa) on S. roflsii cell wall were induced. The 42 kDa endochitinase is induced and expressed on both two substrates.