TRANSGENIC LARCH EXPRESSING GENES FOR HERBICIDE AND INSECT RESISTANCE

Transgenic European larch (Larix decidua Mill.) plants expressing a Ba cillus thuringiensis Berliner (B.t.) toxin gene or the glyphosate tole rance (aroA) gene have been produced using Agrobacterium rhizogenes me diated gene transfer. This procedure relies on direct organogenesis on wounded hypocotyls following A. rhizogenes infection. Hypocotyls of s even-day-old larch seedlings were inoculated with A. rhizogenes strain 11325, harboring the oncogenic nopaline-type pRi11325 and either bina ry vector pCGN1133 containing 35S NPTII and 35S ssu/aroA or pWB 139 co ntaining 35S NPTII-B.t. gene. Adventitious shoot buds were induced 4 w eeks after infection. Shoots were excised, elongated, and rooted on se lection medium containing kanamycin. Needles from greenhouse-grown pla nts were confirmed to have and to express the B.t. or aroA gene throug h Southern, Northern, and Western blot analyses and bioassays. This is the first report of regeneration of transgenic conifer plants express ing value-added genes using Agrobacterium-mediated gene transfer.