Test of Insect-Resistance of Transgenic Poplar with CpTI Gene

Both non-transgenic hybrid triploid poplars[(Populus tomentosa
×P. bolleana
)×P. tomentosa
] and transgenic ones expressing cowpea trypsin inhibitorwere cut at the base of the stem to produce auxoblasts, and used as source of leaves for insect feeding trials performed on 3 major insect species of poplar, the forest tent caterpillar (Malacosoma disstria
L.), gypsy moth (Lymantria dispar
L.)and willow moth (Stilpnotia candida
Staudinger). The height and basal diameter of trees were measured by the end of that year (2000). The results indicated that the growth elements of transgenic poplars were not interfered by the incorporation of the CpTI
gene. Intriguingly, the height and basal diameter of the clone TG04 were much greater than that of the control. The transgenic foliage consumed by insects induced the increase of larval mortality, and decrease of larval wet weight gain, faecal output, pupal weight and egg deposition. Among them 3 transgenic clones, TG04, TG07 and TG71 received special attention for their outstanding insect resistance compared with other transgenic clones, which showed that the CpTI
gene in them was expressed more actively and stably than in others.