Probable tryptophan aminotransferase that may be involved in the regulation of auxin production in developing rice grains. 2-oxoglutarate + L-tryptophan = indole-3-pyruvate + L-glutamate Plant hormone metabolism; auxin biosynthesis. Highly expressed in anthers. Expressed at low levels in ovaries. During grain filling, expression increases from 4 to 20 days after pollination and then decreases to basal levels. Belongs to the alliinase family.