The sweetpotato ADP-glucose pyrophosphorylase gene (ibAGP1) promoter confers high-level expression of the GUS reporter gene in the potato tuber

Abstract

Molecular farming refers to the process of creating bioengineered plants with the capability of producing potentially valuable products, such as drugs, vaccines, and chemicals. We have investigated the potential of the sweet potato ADP-glucose pyrophosphorylase acne (ibAGP1) promoter and its transit peptide (TP) as an expression system for the mass production of Foreign proteins in potato. The ibAGP1 promoter and its TP sequence were transformed into potato along with beta-glucuronidase (GUS) as a reporter acne, and GUS activity was subsequently analyzed in the transgenic potato plants In tuber tissues, GUS activity in transgenic plants carrying only the ibAGP1 promoter (ibAGP1.:GUS) increased tip to 15.6-fold compared with that of transgenic plants carrying only the CaMV35S promoter (CaMV35S. GUS). GUS activity in transgenic plants was further enhanced by the addition of the sweetpotato TP to the recombinant vector (ibAGP1::TP: GUS), with tuber tissues showing a 26-fold increase in activity compared with that in the CaMV35S:.GUS-transgenic lines. In leaf tissues, the levels of GUS activity found in ibAGP1::GUS-transgenic lines were similar to those in CaMV35S::GUS-lines, but they were significantly enhanced in ibAGP1::TP.:GUS-lines. GUS activity gradually increased with increasing tuber diameter in ibAGP1:.GUS-transgenic plants, reaching a maximum level when the tuber was 35 mm in diameter In contrast. extremely elevated levels ofGUS activity - tip to about 10-fold higher than that found in CaMV35S..GUS-lines - were found in ibAGP1:TP..GUS-transgenic lines at a much earlier stage Of tuber development (diameter 4 mm), and these higher levels were maintained throughout the entire tuber developmental stage These results suggest that the sweetpotato ibAGP1 promoter and its TP are a potentially strong foreign gene expression system that can be used for molecular farming in potato plants. To cite this article: T-W. Kim et al., C R. Biologies 332 (2009). (C) 2009 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.