  Natalia Dudareva, a distinguished professor of horticulture,
and Hiroshi Maeda, a postdoctoral researcher in Dudareva's
laboratory, determined that the gene is one of 10 responsible
for phenylalanine production in plants. Understanding how the
amino acid is produced could provide a strategy to increase or
reduce that production.   Phenylalanine is important for plant
protein synthesis and for the production of flower scent, anti-
oxidants and lignin, a principal plant cell wall component that
helps plants stand upright and acts as a barrier in the
production of cellulosic ethanol. It is one of the few essential
amino acids that humans and animals cannot synthesize, so it
must come from plants.    "In plant tissues where we want to
lower lignin content, we may be able to block these pathways,"
Maeda said. "In cases where you want to increase the amount of
phenylalanine, we could do that as well."    Decreasing
phenylalanine could lead to a reduction in lignin, which would
improve digestibility of cellulosic m