Caterpillar genes

The two key partners in the Helicoverpa project are the Batterham’s team from the University of Melbourne and the CSIRO Division of Entomology, in particular the chief scientist in that division, Dr John Oakeshott, who worked on the Honey Bee Genome project, and another scientist in the division, Dr Karl Gordon, who has described telomeres and identified the gene for telomerase in honey bees.

While this project is almost exclusively Australian funded – and, scientifically, Australia is taking the lead – we can’t actually do it all alone, and nor do we want to, Batterham says.

Other partners include a team led by David Heckel from the Max Planck Institute for Chemical Ecology and another from INRA, the National Institute for Agricultural Research in France, led by Rene Feyereisen.

Feyereisen has already done some sequencing of the Helicoverpa genome, information that will be used in piecing it all together.

The bulk of the sequencing work will be done by Richard Gibbs’ team at Baylor College of Medicine’s Genome Centre, which has worked on the wallaby, the platypus, the cow, the human and a large number of insects.

Batterham says most of the sequencing will be devoted a deep and thorough job on Helicoverpa armigera, but a light coverage will also be done on a number of other Helicoverpa species.

“So far we’ve got 3.6-fold coverage of the genome,” he says. “That means we already have some sequences of probably almost every gene in the genome but the sequence is all in pieces. There are probably roughly around 14 or 15,000 genes in this genome – we’ve got a piece of all of them, but we can’t piece together whole genes yet and we can’t piece all of the genes together yet until we finish the sequencing.

“We are doing light coverage of other species and we are also doing very detailed analysis of genes that are expressed in key tissues. For example, the mid-gut of an insect is really important – that is where a lot of the metabolism of a lot of insecticide occurs, and that is where some of the primary targets might be found, because if you want to use insecticides, the protein that they are going after needs to be in tissues that the insecticide will reach.

“So the mid-gut is always considered to be a good target tissue, but we’ll look at a range of tissues to see which genes are expressed there and we’ll also look at the expression of genes throughout development, because some stages of development are clearly more important – the caterpillar is the most important.”