Ar. Fernie et al., Simultaneous antagonistic modulation of enzyme activities in transgenic plants through the expression of a chimeric transcript, PL PHYS BIO, 39(10), 2001, pp. 825-830
The aim of this work was to investigate the possibility of modulating diffe
rent enzyme activities in an antagonistic manner using a single transgenic
approach. To this end a yeast (Saccharomyces cerevisiae) cDNA encoding for
a beta -fructosidase (invertase; EC 3.2.1.26) was introduced into a binary
vector in the sense orientation directly coupled to a fragment of the cDNA
encoding for the small subunit of potato (Solanum tuberosum) AGPase (EC 2.2
.7.27) in the antisense orientation. Transgenic plants were generated by Ag
robacterium-mediated transfer with the expression of both cDNAs being under
the control of the tuber specific B33 patatin promoter. The resulting tran
sformants were screened by analysis of metabolites which are known to chang
e when the targeted enzymes are modulated. Finally, northern analysis coupl
ed with enzymatic analysis revealed that the chimeric gene was expressed an
d that expression led to both the production of yeast invertase and the ant
isense repression of the endogenous potato AGPase activity. We therefore co
nclude that this method will be of use in metabolic engineering strategies
that require a simultaneous up-regulation of one pathway and an inhibition
of a second competing pathway. (C) 2001 Editions scientifiques et medicales
Elsevier SAS.