Affiliation:
1. 1Department of Agricultural Science, Okayama University, Okayama 700, Japan
2. 2Department of Biotechnology, Faculty of Engineering, Osaka University, Osaka 565, Japan
Abstract
Abstract Oligomers (dimer to heptamer) of chitosan and their partially/completely N-acetylated derivatives were examined for (+)-pisatin-inducing activities in pea epicotyl elicitor assay at concentrations ranging from 6.25 to 100 μg/ml. The structures of the oligomers were analyzed by 1H NMR and MALDI TOF MS spectrometers. The chitosan oligomers from dimer to tetramer were inactive, while the pentamer exhibited a moderate activity at 100 μg/ml. The hexamer showed a pronounced activity at 100 μg/ml, whereas the oligomer had no activity at the higher concentrations. Although the chitosan heptamer induced a moderate amount of (+)-pisatin (ca. 60 μg/g fr. wt.) at 50 μg/ml, the oligomer did not elicit pisatin formation at 100 μg/ml. The dimer to tetramer of both partially N-deacetylated chitin (DAC) and chitin were totally inactive. The DAC pentamers (d.a. 31%, 52%), DAC hexamers (d.a. 26%, 41%), and DAC heptamers (d.a. 26%, 36%) exhibited significant elicitor activities at lower concentrations (6.25-25 μg/ml) than the native chitosan oligomers. The chitin pentamer to heptamer had weak or no activity. Both glucosamine and N-acetylglucosamine were inactive in the assay. These facts suggest that the DAC pentamer to heptamer may act as elicitors for pisatin induction in pea-fungus interactions.
Subject
General Biochemistry, Genetics and Molecular Biology
Cited by
17 articles.
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