Abstract
In order to produce useful metabolites in leaves of transgenic plants, we characterized the activity of a promoter that is strongly expressed in green tissues. In addition, we used this promoter to control the expression of OASA1D, a mutated rice anthranilate synthase alpha subunit gene that is insensitive to feedback regulation, to produce transgenic rice with high tryptophan levels in green tissues.
GUS gene under the control of the 2 kb promoter region of the rubisco activase (pRCA) was expressed in leaf blade, leaf sheath, lemma, palea, anther and pollen, but not in callus; it was locally expressed in root. In leaf blade, pRCA-GUS activity was about 2-5 times stronger than 35S-El2 omega-GUS construct. The pRCA-OASA1D transgenic rice accumulated high amounts of free tryptophan in leaf blade and seeds at levels similar to that obtained from ubiquitin promoter-OASA1D construct.
