The effect of chitosan on the growth and physiology of two wood inhabiting fungi

IRG/WP 06-10590

D Vesentini, T Singh

The effect of chitosan on the wood inhabiting fungi Sphaeropsis sapinea and Trichoderma harzianum was evaluated at cellular level. Increasing concentrations of chitosan caused an increase in the amount of peroxide in cultures of S. sapinea, which was accompanied by a simultaneous decrease in superoxide. The same effect was not observed in T. harzianum. The growth of both fungi was inhibited when hydrogen peroxide was added to the culture medium, but the inhibitory effect of hydrogen peroxide was alleviated by addition of catalase. Furthermore, addition of catalase to the chitosan-amended medium also lead to improved growth for both species, suggesting that oxidative stress might act concurrently to chitosan toxicity under these conditions. Chitosan affected membrane permeability in both species and lead to increased leakage of potassium ions. The results are discussed with a view to the potential mechanisms mediating chitosan toxicity in these two fungi.

Keywords: chitosan, potassium leakage, oxidative stress, Sphaeropsis sapinea, Trichoderma harzianum, plasma membranes, mode(s) of action

Conference: 06-06-18/22 Tromsoe, Norway

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