, Volume 23, Issue 4, pp 759-768  Concerted regulation of lysine
and threonine synthesis in tobacco plants expressing bacterial
feedback-insensitive aspartate kinase and dihydrodipicolinate
synthase  Purchase on Springer.com  $39.95 / €34.95 / £29.95*
Rent the article at a discount  Rent now  * Final gross prices
may vary according to local VAT.  Get Access   The essential
amino acids lysine and threonine are synthesized in higher
plants by two separate branches of a common pathway. This
pathway is primarily regulated by three key enzymes, namely
aspartate kinase (AK), dihydrodipicolinate synthase (DHPS) and
homoserine dehydrogenase (HSD), but how these enzymes operate in
concert is as yet unknown. Addressing this issue, we have
expressed in transgenic tobacco plants high levels of bacterial
AK and DHPS, which are much less sensitive to feedback
inhibition by lysine and threonine than their plant
counterparts. Such expression of the bacterial DHPS by itself
resulted in a substantial overproduction of lysine,