Expression of the green fluorescent protein gene in conifer tissues.

The gene coding for the green fluorescent protein (GFP) from jellyfish was introduced into conifer tissues by microprojectile bombardment and its transient expression was detected. Two versions of the GFP gene, wild-type GFP and modified GFP with a cryptic intron removed, were directly compared for their expression in black spruce pollen. While the wild-type GFP gene resulted in a low level of expression, the modified GFP gene gave a dramatic increase in amount of expression (>100 times). The expression of GFP was detected in all the tissues tested : pollen, embryonal masses, suspension culture, and somatic embryos. Also, the GFP gene was introduced and expressed in three different conifer species (black spruce, white spruce, and white pine). The successful expression of the GFP gene in various tissues and different species suggests that it will be a useful reporter/marker gene for conifers.