Enhanced insect resistance in Thai rice varieties generated by particle bombardment

We used particle bombardment to transform two elite Thai rice varieties, Khao Dawk Mali 105 (KDML105) and Supanburi 60 (SP60), with the snowdrop lectin gene gna (Galanthus nivalis agglutinin). This gene confers resistance to sap-sucking insects such as the brown planthopper (BPH; Nilaparvata lugens), which is one of the most damaging pests of rice. Traditionally, KDML105 and SP60 have been regarded as recalcitrant to transformation, and this is the first account of successful gene transfer to these varieties. By molecular analysis, we confirmed the recovery of over thirty gna-transgenic lines. GNA protein expression was characterised by western blot analysis, and we achieved expression levels of up to 0.25% total soluble protein. GNA-producing R-1 transgenic plants were significantly more resistant to BPH than control plants (P < 0.0001), with 37% and 42% reduction in nymphal survival for constitutive and phloem-specific expression, respectively. Transferring the gna gene to these superior rice varieties thus represents a major step forward for crop improvement in Thailand, and should help to reduce the damage caused by rice pests, and hence increase yields for this vital domestic and export market.