Potato and Tobacco Genes Fend Off Cotton Pests

Researchers from La Trobe University in Melbourne reported that plants like potato and tobacco contain pest-killing genes could be used to protect cotton. Previous studies have shown that plants like potato and tobacco contain chemicals that are toxic to pests called proteinase inhibitors (PIs) block caterpillar gut enzymes that are used to digest protein. However, Professor Marilyn Anderson and colleagues discovered that the pests soon adapt to the PIs. Thus, they searched for a way to use the PI genes to efficiently protect cotton from pests.

The researchers studied the gut of caterpillars exposed to PIs from tobacco and found that the adaptation of pests was due to the turning on of genes that code for new proteases that are not affected by tobacco PIs. They isolated these newly turned on genes and searched for PIs that could inhibit the new proteases. They found these PIs from the leaves of potato. Thus, they used the genes coding for PIs from both tobacco and potato and engineered them on cotton plants. Field trials showed that the cotton yields increased by 21%, compared with the previous GE cotton with PI only coming from tobacco which did not improve the yield at all.

The open-access article can be downloaded at http://www.pnas.org/cgi/doi/10.1073/pnas.1009241107.