Insect infestation can be devastating for farmers, so researchers are constantly looking for new ways to protect crops. To that end, findings published in the October issue of Nature Biotechnology could help. Scientists have sequenced the complete genome of a symbiotic bacterium that is toxic to insects in the hope that the results will lead to novel insecticides.

Photorhabdus luminescens lives in the guts of small soil worms known as nematodes. It helps the nematodes kill insect prey by releasing a variety of virulent proteins. Frank Kunst of the Pasteur Institute in France and his colleagues analyzed the 5,688,987 base pairs that comprise P. luminescens' genetic code and discovered 4,839 genes that produce proteins. The authors note that "more toxin genes were predicted in the P. luminescens genome that in any other bacterial genome sequenced yet." The researchers hope that some of these toxins can be modified to provide alternatives to currently used insecticides, which insect populations can sometimes develop resistance to. (This effect has been observed in worm and moth populations exposed to the insecticide produced by the bacterium Bacillus thuringiensis, also know as Bt.) In addition, they suggest that genetic engineering of the bacterium-nematode pair could lead to novel methods of biological control, perhaps through releasing the duo into areas in which it is not typically found.