The expression patterns of chitinase were investigated in tomato after treatment with chitosan, and chitooligosaccharide as an immune-elicitor, with and without the phytopathogen Fusarium oxysporum and antagonist bacterium, Bacillus thuringiensis, in ...
The expression patterns of chitinase were investigated in tomato after treatment with chitosan, and chitooligosaccharide as an immune-elicitor, with and without the phytopathogen Fusarium oxysporum and antagonist bacterium, Bacillus thuringiensis, in chitosan beads. Chitinase isozymes were shown to have three molecular weights, 25, 65, and 70 kDa, through western blotting with alkaline-phosphatase and horseradish peroxidase-conjugated secondary antibodies. The isoelectric point (pI) ranges of the chitinase isozymes were pI 5-6 (in 65 and 70 kDa) and pI 7.2 (in 25 kDa). The total protein contents were higher at 12 and 24 h in shoots and for the growth period in roots infected with F. oxysporum than those in control plants. The chitinase activity was higher at 12, 24, and 36 h than control plants in tomato roots infected with F. oxysporum. The expression pattern of chitinase was very low in tomato shoots at 24 h after infection with F. oxysporum. The expression patterns of chitinase were much more strongly induced in the roots than the shoots at 24 h after treatment with chitosan, chitosan oligomers, and F. oxysporum. Chitosan activity staining showed the strongest bands at 7 d after F. oxysporum treatment in the shoots and roots. Chitosan activity staining showed strong bands in the treatment with mixed B. thuringiensis GS-2 and chitosan beads in the shoots and roots of tomato. These results indicate that B. thuringiensis GS-2 in chitosan beads could be used as a potential antifungal agent for biological control in agriculture fields.