Inhibition of IAA oxidase activity of wheat anionic peroxidase by chitooligosaccharides

Resumo

The study demonstrated that chitooligosaccharides with a molecular weight of 5–10 kDa and a degree of acetylation of 65% exhibited an auxin-like effect in wheat plants and also played an important role in regulating the activity of polysaccharide (chitin)–specific anion isoenzymes of peroxidase oxidizing indole acetic acid. Changes in the kinetic parameters of the interaction of the wheat anionic chitin-specific peroxidase with pI ∼3.5 with chitin oligomers in the presence of indoleacetic acid were pH-depended and indicated that chitooligosaccharides significantly impair the ability of the enzyme for oxidation at pH levels of 4.2 and 6.0. It can be assumed that chitooligosaccharides not only induce protective plant systems but also increase the accumulation of auxin in plant tissues, thus adversely affecting a number of components of the plant protective system against pathogens.