Phenylalanine is an amino acid required for protein synthesis and is a precursor for over 8000 compounds essential for plants, including lignin. Humans and animals can’t make the amino acid and has to get it from plants as it is one of the essential amino acids. It is made from a sugar through the plant’s shikimate pathway. The intermediate steps had not been known until this Purdue research, though there had been two proposed pathways, of which the plants use the arogenate pathway predominantly. The researchers discovered the gene responsible for phenylalanine production and found that the suppression of this gene decreased 80% of the phenylalanine in a petunia plant. But their main surprise was that the plant used the second phenylpyruvate pathway when the researchers forced the shikimate pathway to work by adding shikimic acid. Before, it wasn’t known how plants used the second pathway. It was only theorized. But now that the pathways are proven, phenylalanine production can be controlled. If phenylalanine is increased, this could add nutritional value to foods, or if it is decreased, this could mean less lignin and more digestibility of plant biomass for biofuel production.
Two options and two pathways for Phenylalanine