Abstract:

Three Trichoderma strains, T-33,T-14,T-09, which have inhibiting effects on Cytospora chrysosperma, were derived from 29 domestic and foreign strains with methods of antagonistic culture and growth-inhibition. The extracts obviously inhibited mycelium growth and conidia germination of Cytospore chrysosperma were gained. The effect of the most highly efficient extract on pathogen’s cell physiological indicators and protective enzyme activities was systematically studied. The growth-inhibiting rate of the substances extracted from the fermented liquid of strain T-33 was 94%, and the extract also had an inhibiting effect on spore germination. The extract was able to increase the electrical conductivity and MDA content of the pathogen significantly, reduce the protein content and activity of SDH, PK, HK, LDH, MDH, and coenzyme I, and cause a sharp decline in Na⁺、K⁺-ATP, Mg²⁺-ATP and Ca²⁺-ATP enzymes activities. The results indicated that the pathogen cell membrane would be severely peroxided, and some metabolic pathways such as glycolysis, TCA cycle, electron transport and oxidative phosphorylation, would be restricted. Finally, the extract inhibited pathogen growth by destroying the pathogen’s protection system and metabolic pathways.

Key words: Trichoderma, extract, Cytospora chrysosperma, inhibiting mechanism