Flavonoid biosynthesis: 'New' functions for an 'old' pathway

Flavonoids are important plant secondary metabolites that have been extensively studied using genetic, biochemical and molecular approaches. Recent analyses have focused on our understanding of the role of flavonoids in such well-established processes as plant-microbe interactions and protection against ultraviolet (UV) light, and have also uncovered a previously unsuspected role in male fertility. These studies demonstrate the utility of flavonoid structures for a broad range of activities, and also highlight the value of the flavonoid pathway as a paradigm for studying the evolution of plant metabolism.