| Research Abstract |
Chitin and chitosan are main components of the cell walls of plant pathogens, and chitinase activity is found in almost all plant tissues. The plant chitinase probably degrades fungal cell walls to inhibit fungal growth. In the present study, we have examined the growth of 15 fungi in the presence of a test compound (chitinase, lysozyme, chitosan, protamine, pectic acid, or alginic acid) in a concentration of 1,000 ppm on the potato dextrose agar medium. 1)The growth of 13 fungi was inhibited more than 10% with chitosan (MW 150,000), 9 with low-molecular-weight chitosan (MW 3,000-5,000), 7 with pectic acid, 9 with chitosan oligosaccharides (d.p. 2-8). 2)The growth of 11 fungi was inhibited more than 10% with protamine. 3)The growth of 7 fungi was inhibited more than 10% with pectic acid, and 7 with alginic acid. 4)The growth only 3 fungi was inhibited by lysozyme, and one fungus by chitinase.
These results indicate that the cell surface is disordered by forming polyelectrolyte complexes with amino group for chitosan and protamine, and with carboxyl group for pectic acid and alginic acid.
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