TRANSGENIC LARCH EXPRESSING GENES FOR HERBICIDE AND INSECT RESISTANCE

Transgenic European larch (Larix decidua Mill.) plants expressing a Bacillus thuringiensis Berliner (B.t.) toxin gene or the glyphosate tolerance (aroA) gene have been produced using Agrobacterium rhizogenes mediated gene transfer. This procedure relies on direct organogenesis on wounded hypocotyls following A. rhizogenes infection. Hypocotyls of seven-day-old larch seedlings were inoculated with A. rhizogenes strain 11325, harboring the oncogenic nopaline-type pRi11325 and either binary vector pCGN1133 containing 35S NPTII and 35S ssu/aroA or pWB 139 containing 35S NPTII-B.t. gene. Adventitious shoot buds were induced 4 weeks after infection. Shoots were excised, elongated, and rooted on selection medium containing kanamycin. Needles from greenhouse-grown plants were confirmed to have and to express the B.t. or aroA gene through Southern, Northern, and Western blot analyses and bioassays. This is the first report of regeneration of transgenic conifer plants expressing value-added genes using Agrobacterium-mediated gene transfer.