Ian Mannix
Editor-in-Chief, Cosmos
Scientists have shed new light on the role of well-known wheat gene that influences the yield of wheat, providing knowledge that will help improve farm productivity and build adaptation as the climate changes the weather across major grain-growing regions.
The gene is called Photoperiod-1 (Ppd-1) and it is used regularly by breeders to ensure wheat crops flower and set grain earlier in the season, avoiding the harsh conditions of summer.
“Photoperiod-1, which has contributed significantly to the improvement of varieties in regions like Australia, India and Southern Europe,” says Dr Scott Boden, a Future Fellow at the University of Adelaide’s School of Agriculture, Food and Wine.
“However, the early flowering lines can also produce fewer seed, and this is influenced by the development of its floral structure called a spike. The aim of this study was to understand that effect of Photoperiod-1 in the developing spike by studying the molecular pathways that are controlled by Ppd-1, especially when the grain-bearing florets and spikelets form,” Boden told Cosmos.
“Our work provides new targets that could be used by breeders to improve yield potential, or align flowering with favorable environments, which will be useful as the climate continues to change.”
Boden’s research team is now furthering its work with field trials at the University’s Research Enclosure to test for performance of the gene-edited lines under field conditions.
Serendipitously, German researchers discovered a similar effect for the ALOG1 transcription factor in barley, which provides exciting clues to the evolution of unbranched inflorescences of wheat and barley, relative to those of rice and corn which display more elaborate branching patterns.
Australia is the world’s largest exporter of wheat and produced 36.2m tonnes of the crop in 2022 – the country’s largest annual harvest on record.
“Wheat contributes 20 per cent of calories and protein to the human diet, and scientists and breeders need to find ways to increase grain yields of wheat by between 60 and 70% by 2050 to maintain food security for the growing global population,” says Boden.
“Studies like ours are particularly important because they provide a list of gene targets that can be used with new technologies, such as transformation and gene editing, to generate new diversity that may help improve crop productivity.
“We anticipate our research will lead to further discoveries of genes that control spikelet and floret development in wheat, and in doing so, benefit the development of strategies for improving the yield potential.”
Boden and his team have been working on this project for about 7 years, with part of the work being performed in Adelaide and the rest at the John Innes Centre in the UK, at which Boden worked previously.
He says the research is of global benefit: “The knowledge gained from this work should apply to all wheat varieties. One of the lines we used contains a variant of Photoperiod-1 used commonly in Australian breeding programs, so we think many of the discoveries should transfer well into local varieties.
“But we expect the research outcomes will be useful to breeders all over the world, especially for countries like India, Pakistan, Mexico and China where variation for Photoperiod-1 is used commonly to modify flowering time.”
The fundamental research breakthroughs could be seen to assist farmers in 5 to 7 years although as with all fundamental science, there is some doubt about the time frame.
“It isn’t clear exactly how this will apply to farmers,” says Boden.
“In terms of commercial considerations, the mutant lines we used to confirm gene function were generated using CRISPR/Cas9 gene-editing, and it is likely that licences will need to be obtained to release these seed commercially if further analysis indicates they could benefit farmers.
“But for the gene expression work, we believe the outcomes could benefit breeders immediately by providing knowledge about genes that should now be targeted in breeding programs to improve fertility.
“We expect our results will also help other wheat researchers identify genes that control major yield-related traits, and the benefits of this work may take 5-10 year before helping farmers.
“We will be doing a GMO (genetically modified organisms) field trial this year to see if the mutant improves grain yield. If so, then we will introduce these edits into elite lines and they could be released in 5-7 years, depending on licencing requirements related to the use of CRISPR.”
The understanding of wheat genetics comes at a time when farmers are adapting to a climate being impacted by greenhouse gasses and fossil fuel emissions.
“Flowering time is a major consideration for farmers, because early flowering lines risk being hit by frost, while late flowering lines are affected by terminal season heat and drought,” says Boden.
“We anticipate that traditional optimum flowering period will change as the climate shifts, and so varieties will be required that offer farmers alternate strategies for sowing and flowering-time. One of the lines identified here could contribute to new flowering time strategies, especially in multi-cropping systems.
The research was published in Current Biology.
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The Greenlight Project is a year-long look at how regional Australia is preparing for and adapting to climate change.