RNA interference-mediated silencing of the key flavonoid and isoflavone biosynthesis
enzyme, respectively, by two different research groups has provided direct genetic evidence
for the essential roles that these compounds play in nodulation. Anton Wasson et al. have
shown that flavonoids are essential for localized auxin transport inhibition during nodulation
in the indeterminate legume Medicago truncatula. By contrast, Senthil Subramanian et al.
have shown that isoflavones are essential for endogenous nod gene induction in the …