Gene Editing Boosts Heat-Resistant Wheat Hopes
Discovery raises optimism for the future of this vital crop.
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Techniques such as gene editing are poised to help combat the effects of climate change on global agriculture. By manipulating an organism’s DNA, scientists can learn more about which genes underpin important functions, such as heat tolerance. Harnessing that understanding, they might be able to breed more resilient crops in the future.
Wheat fertility and yield are highly temperature-sensitive. Concerns are mounting, therefore, as to how this vital crop will endure our planet’s rising temperatures. “Studies have already shown that wheat yields fell by 5.5% during 1980-2010, due to rising global temperatures,” Diego N.L. Pequeno, a wheat crop modeler at the International Maize and Wheat Improvement Center (CIMMYT), said.
Researchers at the John Innes Centre, led by Professor Graham Moore, are working to identify genes that help stabilize wheat fertility in temperatures outside of the 17–23 °C range where meiosis functions most efficiently.
In the early stages of meiosis, parental chromosomes align next to each other as pairs, which enables the formation of the synaptonemal complex (SC), linking the chromosomes. This process ensures that chromosomes from parental cells are crossed over and create seeds for future generations, but can be impacted negatively by high or low temperatures.
Gene’s role in heat tolerance validated
Previous research has implicated the DMC1 gene in protecting wheat meiosis when temperatures fluctuate. Moore and colleagues’ latest study in Frontiers in Plant Science served to validate that role.
The researchers developed mutant forms of Chinese Spring Wheat lacking DMC1 using CRISPR-Cas9, a sophisticated gene-editing technique. Through controlled experiments, they observed the impact that different temperatures had on the mutated plants.
Mutant plants grown at 13 °C were significantly affected, demonstrating a 95% reduction in crossover number. Mutants grown at 30 °C – the other end of the temperature scale – showed a reduced number of crossovers and univalence after 24 hours, though the researchers noted that these effects were “less marked than at 13 °C”.
The work confirms the team’s previous hypothesis that DMC1 helps to preserve crossover formation at low and, to a degree, high temperatures. “Thanks to gene editing we have been able to isolate a key temperature tolerance gene in wheat. It provides cause for optimism in finding valuable new traits at a time when climate change is challenging the way we grow our major crops,” said Moore.
Identifying more heat-tolerant genotypes
Moore and colleagues will now search for variations of DMC1 that could provide further protection to wheat. They will also test how the expression levels of the gene influence the level of protection observed.
“Climate change is likely to have a negative effect on meiosis and therefore on wheat fertility and ultimately crop yields, so screening of germplasm collections to identify heat-tolerant genotypes is a high priority for the future of crop improvement,” Moore concluded.
Reference: Draeger TN, Rey MD, Hayta S, Smedley M, Martin AC, Moore G. DMC1 stabilizes crossovers at high and low temperatures during wheat meiosis. Front Plant Sci. 2023;14. doi: 10.3389/fpls.2023.1208285
This article is a rework of a press release issued by the John Innes Centre. Material has been edited for length and content.