TIMED TO PERFECTION
BY TREVOR BACQUE
Scientists at Agriculture and Agri-Food Canada’s Lethbridge Research and Development Centre have successfully edited multiple genes in two spring wheat lines in efforts to create greater environmental adaptability.
Related to the Ppd-1 gene, the newly edited genes are also part of a group of a dozen or so genes that collectively govern a plant’s circadian clock. These genes help determine when the plant starts and stops photosynthetic activity each day, in addition to other metabolic activity important for light and dark cycles.
The Ppd-1 gene is active around midday, when a plant typically transitions away from heavy photosynthetic activity and into more secondary metabolism to make things like starch and defence compounds, according to research scientist John Laurie who was integral to the genes’ discovery.
With the wheat genome having been successfully sequenced in 2018, scientists can create variation through gene editing. “We don’t have to search around the world to find diverse lines and make the crosses and do the tedious process of discovering which of the mutations are responsible for certain traits,” he said. “We can just do it directly without making any crosses. We can use gene editing to create variation at these clock genes and see which types of variation are important for certain traits.”
Like the natural variation in Ppd-1, creating additional clock mutants that will allow wheat plants to either flower earlier or later in the season is advantageous. This can ultimately be a net positive for farmers who contend with prolonged periods of heat and dryness across the Prairies. Wheat that flowers prior to the typical July heat blast would be of special value. Most excitingly, Laurie and his team have discovered special clock mutants that possess enhanced drought tolerance.
“We plant this line, starve it of water and it does much better than the control line,” he said. “Because we know precisely what clock gene variation we created, we are now actively looking at downstream signalling pathways and metabolism to see how this particular change results in the drought tolerance we see.”
Laurie is confident further editing of additional clock genes will produce wheat with even greater yields and positively impact the crop around the world. It may be 10 years until these lines are commercially available, he added, but believes the agronomic upside will be noticeable.
Another proponent of gene editing and its potential is Gurcharn Brar, a wheat breeder and assistant professor of wheat breeding and genetics at the University of Alberta. Gene-editing research comes at a time when many farmers look to use all the climatic assistance possible. “This research is timely and interesting to look at the circadian clock in wheat and try to alter it with gene editing, particularly under drought,” he said.
While it may show early agronomic promise, market acceptance of gene-edited wheat is virtually non-existent. This has little to do with Canada and more to do with the policies and regulations of trading partners.
Most countries, including Canada’s primary trade partners, are working to establish positions on crops with gene-edited features. This could prove a massive barrier, especially if the wheat cannot be sold internationally, explained Brar.
“Gene editing is a very powerful tool, and we hear about that all the time, but sometimes scientists oversell it,” said Brar. “We breeders know how to use these technologies, and we have incorporated them, but it still has a lot of things that are policy dependent more than the technology itself. To say it can accelerate variety development, it is not true because we can’t use the technology at least until there’s global, universal acceptance.”
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