M. Bellucci et al., Expression of maize gamma-zein and beta-zein genes in transgenic Nicotianatabacum and Lotus corniculatus, PL CELL TIS, 62(2), 2000, pp. 141-151
Accumulation of zeins, the endosperm storage proteins of maize, in a hetero
logous plant expression system was attempted. Plants of Nicotiana tabacum a
nd Lotus corniculatus were transformed by Agrobacterium with binary vectors
harbouring genes that code for gamma -zein and beta -zein, two zeins rich
in sulphur amino acids. Adding the ER retention signal KDEL to the C-termin
al domain modified the zein polypeptides. Significant levels of gamma -zein
:KDEL and beta -zein:KDEL were detected in primary transformants of tobacco
. Moreover, the two zeins colocalized in leaf protein bodies of gamma-/beta
-zein:KDEL plants derived from a cross between two primary transformants.
Coexpression of gamma -zein:KDEL and beta -zein:KDEL could be a useful stra
tegy to obtain genotypes of forage legumes which are able to accumulate sul
phur amino acids to high levels. As a first step, L. corniculatus plants ex
pressing gamma -zein:KDEL in the leaves were obtained.