Tearless Onion in the Works

Although they are still in the developmental stages, tearless onions will likely be widely available within the next decade.

Colin Eady, Ph.D., senior scientist, Crop & Food Research, Christchurch, New Zealand, says research on the tearless onion is based on a gene-silencing technology called RNAi, developed by Peter Waterhouse, Ph.D., and Ming-Bo Wang, Ph.D., scientists at CSIRO, Dickson, Australia.

Through RNAi, genes can be specifically shut down or turned off, Eady explains. By shutting down the lachrymatory-factor synthase gene (the enzyme responsible for the tearing effect), we have stopped valuable sulfur compounds being converted to the tearing agent, and instead made them available for redirection into compounds, some of which are known for their flavor and health properties. He says that, when crushed, the model tearless onions do not induce tearing.

Eady hopes that, beyond being tearless, the onion will be capable of being grown in an efficient manner. We have a burgeoning population to feed, and with climate change and other challenges, available resources are being reduced, he says. The gene silencing system can also be used to combat viruses and diseases, and biotechnology, in general, can help us produce more robust crops.