Bt Tomato with Cry6a Found Resistant to Root-Knot Nematodes

Transgenic tomato plants expressing modified Bacillus thuringiensis (Bt) cry6A genes were found to have increased resistance to the root-knot nematode Meloidogyne incognita. This is the first time that a Bt Cry protein was demonstrated to confer plant resistance to an endoparasitic nematode, and that Cry proteins are reported to have the potential to control plant-parasitic nematodes in transgenic plants.

Researchers at the University of California tested two cry6A genes – one was modified not to have codons (sets of three DNA bases that code for an amino acid) uncommon in plants, and the other altered to include only optimal codons for each amino acid based on studies in Arabidopsis. The researchers report that there was a fourfold decrease in progeny production of the nematode pest brought about by cry6A expression in the plants. They recommend that cry6A be ‘stacked’ in crop varieties with other nematode-resistant traits.

The paper, published by the Plant Biotechnology Journal, can be accessed at
http://www.blackwell-synergy.com/doi/abs/10.1111/j.1467-7652.2007.00257.x.