4-Hydroxyphenylpyruvate dioxygenase (EC 1.13.11.27, HPPD) is an important enzyme in the catabolism oftyrosine, which converts 4-hydroxyphenylpyruvate (HPPA) into homogentisate (HGA).In plants, HGA is an important precursor for the biosynthesis of tocopherol and plastoquinone, two compounds crucial for the normal growth of plants.When HPPD is inhibited, the plant will be severely damaged by sunlight, becoming bleached and eventually undergoing necrosis and death.[1-3] Inhibition of HPPD is one of the most promising modes of action of herbici...
