Discovery brings wheat flowering mechanism to light
That handy chart on the back of seed packet tells backyard gardeners when it’s time to plant based on where they live. Things get a bit more complicated, however, when your goal is to feed the world.
Researchers at the University of California–Davis have unlocked a long-held secret into how wheat determines when it’s time to flower. This information is critical to wheat growers because flowering marks the transition between the plant’s growing period and the reproductive stage when the actual grain is created. Equipped with this knowledge, breeders can develop better adapted varieties to help growers maximize yield.
UC Davis professors Jorge Dubcovsky and Clark Lagarias, worked with a particular set of plant proteins called phytochromes that can sense differences in light and regulate the responses of other plant genes. His research indicates that Phytochrome C (“PhyC”) plays a much more significant role in the regulation of wheat flowering than was previously believed. When activated by the red spectrum of light, PhyC changes form and activates a gene known as Photoperiod 1, which is also regulated by the 24-hour day/night cycle (the circadian clock). The simultaneous regulation by an external light signal and the internal circadian clock is required to measure the length of days and nights. If PhyC is inactivated, wheat flowering is delayed by more than 100 days.
Results from this research are highlighted in this month’s edition of Proceedings of the National Academy of Sciences. The project was funded by two Agriculture and Food Research Initiative grants administered by the U.S. Department of Agriculture’s National Institute of Food and Agriculture (NIFA).
Dubcovsky said his lab’s goal was to understand the effects of different genes on wheat flowering. Follow-on researchers can now look for natural variants of PhyC to create new varieties of wheat with accelerated or delayed flowering. Wheat breeding programs around the world already use molecular markers for other flowering genes previously identified in Dubcovsky’s laboratory to design new crosses and to optimize yield in new and changing environments.
“The more we understand about wheat development and its regulation, the more we will be able to engineer a response we want to the environment,” he said.
According to Dubcovsky, wheat provides about one-fifth of the calories consumed by humans, has high levels of protein, is easy to transport, and stores for long periods of time – all characteristics that make wheat critical for world food security. “We need to maximize wheat production to feed a human population that will exceed 9 billion people by 2050,” he said.
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