Transgenic rice homozygous lines expressing GNA showed enhanced resistanceto rice brown planthopper

Mature seed-derived calli from two elite Chinese Japonica rice (Oryza sativ a L.) cultivars Eyi 105 and Ewan 5 were co-transformed with two plasmids, p WRG1515 and pRSSGNA1, containing the selectable marker hygromycin phosphotr ansferase gene (hpt), the reporter beta -glu-curonidase gene (gusA) and the snowdrop (Galanthus nivalis) lectin gene (gna) via particle bombardment. 6 1 independent transgenic rice plants were regenerated from 329 bombarded ca lli. 79% transgenic plants contained all the three genes, revealed by PCR/S outhern blot analysis. Western blot analysis revealed that 36 out of 48 gna -containing transgenic plants expressed GNA (75%) at various levels with th e highest expression being approximately 0.5% of total soluble protein. Gen etic analysis confirmed Mendelian segregation of transgenes in progeny. Fro m the R2 generations whose R1 parent plants showing 3:1 Mendelian segregati on patterns, we identified five independent homozygous lines containing and expressing all the three transgenes. Insect bioassay and feeding tests sho wed that these homozygous lines had significant inhibition to rice brown pl anthopper (Nilaparvata lugens, BPH) by decreasing BPH survival and overall fecundity, retarding BPH development and declining BPH feeding. These BPH-r esistant lines have been incorporated into rice insect resistance breeding program. This is the first report that homozygous transgenic rice lines exp ressing GNA, developed by genetic transformation and through genetic analys is-based selection, conferred enhanced resistance to BPH, one of the most d amaging insect pests in rice.