The simplest approach to genetic engineering involves expressing
a gene constitutively, that is, in all tissues of the plant.
The figure shows canola plants that have been
inoculated at the stems with the blackleg fungus, Leptosphaeria maculans.
The stems of untransformed plants are completely girdled, resulting in
plant death. Plants containing the constitutively-expressed
pea defense gene DRR206 exhibit
no symptoms and grow vigorously.
Left: untransformed Westar canola
Right: Westar canola transformed with pea defense gene DRR206
Wang Y. Nowak G, Culley D, Hadwiger L, Fristensky B (1999). Constitutive
expression of pea defense gene DRR206 confers resistance to blackleg (Leptosphaeria
maculans) disease in transgenic canola (Brassica napus). Molecular
Plant-Microbe Interactions 12:410-418.
Fristensky Lab Web Site