University scientists unpeel secrets of onion

University of Otago biochemists Associate Prof Richard Macknight and assistant research fellow Robyn Lee, pictured with an onion and  thale cress plants in a university plant research area. Photo by Craig Baxter.
University of Otago biochemists Associate Prof Richard Macknight and assistant research fellow Robyn Lee, pictured with an onion and thale cress plants in a university plant research area. Photo by Craig Baxter.

University of Otago biochemistry researchers Associate Prof Richard Macknight and Robyn Lee may have just had a four-year-long close encounter with onions but have shed no tears.

And the two scientists are now understandably happy after their research - undertaken with Plant and Food Research - uncovered the previously unknown molecular mechanisms controlling onion bulb formation, in response to lengthening days.

''It was a fantastic piece of research. We don't often make that kind of discovery,'' Prof Macknight said.

Earlier research, conducted in the 1920s, had pointed to a link between bulb formation in onions and seasonal day length.

But the exact nature of the mechanism involved had remained unknown for more than 90 years until the research, led by Prof Macknight.

He was ''delighted'' with the outcome, and the research was published yesterday in the online journal Nature Communications, with a related publication in Theoretical and Applied Genetics.

Onions were the world's third-largest vegetable crop, researchers said. And onions are New Zealand's second-largest vegetable crop - behind potatoes - with 586,000 tonnes produced each year, generating $62 million in export revenue.

The latest research will help pave the way for breeding onions which more reliably produce bulbs when required, in this country. It will also help in the eventual breeding of onions better tailored to grow in other climatic conditions abroad, and at different times.

The research showed how new genome technologies could make possible ''major discoveries'' that would have been difficult in the past, he said.

It was ''incredible'' what had been achieved by using multimillion-dollar high-throughput genetic sequencing equipment, co-ordinated by New Zealand Genomics Ltd (NZGL) and based at the Otago department.

The study was funded by the Ministry of Business, Innovation and Employment.

john.gibb@odt.co.nz