The phenylpropanoid pathway is responsible for the synthesis of numerous compounds important for plant growth and responses to the environment. In the first committed step of phenylpropanoid biosynthesis, the enzyme phenylalanine ammonia-lyase (PAL) deaminates L-phenylalanine into trans-cinnamic acid that is then converted into p-coumaric acid by cinnamate-4-hydroxylase (C4H). | Modulation of auxin and cytokinin responses by early steps of the phenylpropanoid pathway