2 research outputs found
Transplastomic tobacco plants expressing a fatty acid desaturase gene exhibit altered fatty acid profiles and improved cold tolerance
The possibility of altering the unsaturation
level of fatty acids in plant lipids by genetic transformation
has implications for the stress tolerance of
higher plants as well as for their nutritional value and
industrial utilisation. While the integration and expression
of transgenes in the plastome has several potential
advantages over nuclear transformation, very few
attempts have been made to manipulate fatty acid
biosynthesis using plastid transformation. We produced
transplastomic tobacco plants that express a Delta9
desaturase gene from either the wild potato species
Solanum commersonii or the cyanobacterium Anacystis
nidulans, using PEG-mediated DNA uptake by protoplasts. Incorporation of chloroplast antibioticinsensitive
point mutations in the transforming DNA
was used to select transformants. The presence of the
transcript and the Delta9 desaturase protein in transplastomic
plants was confirmed by northern and western
blot analyses. In comparison with control plants,
transplastomic plants showed altered fatty acid profiles
and an increase in their unsaturation level both in leaves
and seeds. The two transgenes produced comparable
results. The results obtained demonstrate the feasibility
of using plastid transformation to engineer lipid
metabolic pathways in both vegetative and reproductive
tissues and suggest an increase of cold tolerance in
transplastomic plants showing altered leaf fatty acid
profiles. This is the first example of transplastomic
plants expressing an agronomically relevant gene
produced with the ‘‘binding-type’’ vectors, which do
not contain a heterologous marker gene. In fact, the
transplastomic plants expressing the S. commersonii
gene contain only plant-derived sequences, a clear
attraction from a public acceptability perspective