Unique fusion genes are disclosed which are useful for transforming a wide range of plants, and when used in tandem, result in a significant alteration of the
plant phenotype with respect to tolerance to the stress from prolonged storage under either dark or cold conditions, or a combination of cold and dark conditions. With intact plants such as transplants, plants harboring these genes maintain the ability of recover and grow normally after returned to
normal growth conditions. With isolated
plant parts, such as
cut flowers or foliage or fruits & vegetables, leaf tissue maintains
color quality and cells maintain
structural integrity during prolonged storage. Since the transgenes are only activated in response to cold temperature, normal
plant growth, development, and function is not affected. The
gene constructs include (1) a cold-regulated
gene (COR15a)
promoter to drive an ipt coding sequence that expresses IPT in the tissues of plants or plant parts exposed to a short cold
induction period; and (2) a cold-regulated
gene (COR15a)
promoter to drive a (FAD7) coding sequence that expresses a
fatty acid desaturase
enzyme in the tissues of plants or plant parts exposed to a short cold
induction period. Exemplary transformations include chrysanthemum, tobacco, flowering tobacco, and
petunia. Double transgenic tobacco, and flowering tobacco both exhibited increased survival under prolonged cold and dark storage conditions.