The Role of Flavan-3-ols and Proanthocyanidins in Plant Defense
W. Feucht, D. Treutter
Abstract
The structural diversity within the flavan-3-ols does not justify a simplifying nomenclature, since small differences in structure, such as the degrees of oxygenation and polymerization or type of interflavan-bonding, change their chemical properties, thus leading to various biological activities. The functions of flavan-3-ols in plant physiology range from scavenging of free radicals to growth regulating activity, from protein precipitation to DNA protection, and from hydration to impregnation of macromolecules of the cell wall. It was found that scab-resistant genotypes possess a high constitutive level of flavan-3-ols under field conditions. It is generally accepted that excessive nitrogen supply favors the primary metabolism and the vegetative growth at the cost of the synthesis of flavan-3-ols. In general, the effect of phytohormones on the metabolism of flavan-3-ols is very complex and closely connected to their growth-regulating activity.