Polyphenol Oxidase as a Component of the Inducible Defense Response in Tomato against Herbivores

摘要: Polyphenol Oxidases (PPOs) are copper-containing enzymes that use molecular oxygen to catalyze the oxidation of monophenolic and ortho-diphenolic compounds (Fig. 1). Both PPOs their phenolic substrates widespread among higher plants fungi. The PPO-generated products, o-qui-nones, spontaneously undergo further reactions form responsible for commonly observed browning injured or diseased plant tissues.1 physiological significance PPO these processes in has remained enigmatic despite intense research efforts, summarized numerous reviews.2–7 Although a wealth studies attempted elucidate role pathogen defense,2,8–10 date most convincing case been made function defense against insects.7,11–14 Interestingly, is important both insect entrapment antinutritive defensive mechanisms, suggesting versatile enzyme which may have other, yet be discovered functions.