| Abstract | Transgenic sugarcane plants engineered to express either the potato proteinase inhibitor II or the snowdrop lectin gene show increased antibiosis to larvae of Antitrogus consanguineus in pot-based glasshouse trials.Canegrubs feeding on the transgenic line UP87, transformed with the potato gene, gained as little as 4.2% of the weight of canegrubs fed on untransformed control plants. Similarly, larvae feeding on the roots of transgenic line G87, transformed with the snowdrop gene, gained only 20.6% of the weight of grubs feeding on the non-transgenic control plants. Overall, 22% of the tested transgenic plant lines engineered with either the potato or the snowdrop constructs resulted in a statistically significant reduction in gain of weight by canegrubs feeding on roots. Weight gains of insects were compared to those of larvae feeding on the roots of either non-transgenic control plants, or non-transgenic plants regenerated after passage through the tissue culture system.Plants transformed with a proteinase inhibitor from an ornamental tobacco showed no statistical effect on the weight gain of the grubs. This result was unexpected, as the proteinase inhibitor from tobacco was predicted to be as effective as the PI from potato. Further analysis of the gene construct by sequencing established that the gene construct was faulty in contrast to the original restriction analysis that had indicated that the plasmid was correctly constructed. Protein could not be produced by the faulty construct, and this is reflected in the negligible effect on weight gain of the grubs. The plasmid was re-constructed and transformed into sugarcane. Plants containing this construct are being grown for testing.Having now established that canegrub resistance can be engineered into sugarcane, the next phase is to test the efficacy of these transgenes against other species of canegrub larvae and to further develop a commercial product. |
