Particle-bombardment-mediated co-transformation of elite Chinese rice cultivars with genes conferring resistance to bacterial blight and sap-sucking insect pests
Kx. Tang et al., Particle-bombardment-mediated co-transformation of elite Chinese rice cultivars with genes conferring resistance to bacterial blight and sap-sucking insect pests, PLANTA, 208(4), 1999, pp. 552-563
Transgenic rice plants were generated using particle bombardment to simulta
neously introduce the Xa21 gene effective against bacterial blight and the
Galanthus nivalis agglutinin (snowdrop lectin; gna) gene effective against
sap-sucking insect pests, specifically the brown plant hopper. Using three
plasmids, we cotransformed 5- to 10-d-old, mature seed-derived rice (Oryza
sativa L.) callus of two elite Chinese rice cultivars, Eyi 105 and Ewan 5.
The plasmids carried a total of four genes. The gna and Xa21 genes were car
ried on separate plasmids. The selectable marker hygromycin phosphotransfer
ase (hpt) and the reporter gene beta-glucuronidase (gusA) were linked on th
e same, co-integrate vector. We recovered over 160 independently derived tr
ansgenic rice plants. Over 70% of the transgenic plants carried all four ge
nes, as confirmed by polymerase chain reaction and/or Southern blot analysi
s. Furthermore, 70% of transgenic plants carrying all four genes also coexp
ressed all four genes, as confirmed by growth on selection media (hpt), GUS
histochemical assays (gusA), western blotting (gna) and reverse transcript
ase-polymerase chain reaction (Xa21) analysis. The co-expression efficiency
reported for the four transgenes in our study is the highest ever found in
any transgenic plant population generated through co-transformation. The l
inked genes (hpt and gusA) co-integrated with a frequency of near 100%, and
we observed a co-integration frequency greater than 70% for the genes carr
ied on separate plasmids. We observed no preferential integration of any pa
rticular gene(s), Genetic analysis confirmed Mendelian segregation of the t
ransgenes in subsequent generations. We report, for the first time, generat
ion and analysis of transgenic rice lines carrying genes effective against
more than one taxa of pathogen or pest, substantiating that particle bombar
dment represents an effective way to introduce unlinked complex multiple tr
aits into plants.