This invention relates to a nucleic acid fragment encoding a plant 5-methyltetra-hydropteroyltriglutamate-homocysteine
methyltransferase or methionine synthase. The invention also includes chimeric
genes, a first encoding a plant methionine synthase (MS) gene, a second encoding
a plant cystathionine -synthase (CS) gene, a third encoding feedback-insensitive
aspartokinase (AK) or bifunctional feedback-insensitive aspartokinase-homoserine
dehydrogenase (AK-HDH), which is operably linked to a plant chloroplast transit
sequence, and a fourth encoding a methionine-rich protein, all operably linked
to plant seed-specific regulatory sequences. Methods for their use to produce increased
levels of methionine in the seeds of transformed plants are provided.