Wednesday, January 26, 2022

"As arable land disappears, a genetic tweak might secure the world’s food supply."

From, January 19, 2022:

Plants Fight for Their Lives

It’s 2050. The world population has increased by 2.3 billion to 9.9 billion. Demand for food has risen 70 to 100 percent but a warming planet, extreme weather, and a decrease in arable land is threatening food security. Luckily, farmers can grow crops more densely, increasing yield from smaller plots of available agricultural land.

Packing crops so tightly wouldn’t have been possible three decades earlier. That’s because despite looking docile, plants are actually hypercompetitive. Grow two plants too close together and they start competing for resources like minerals, water, nutrients, and—once they start to shade one another—sunlight. Without adequate light, plants adapt rapidly through what’s called shade avoidance response (SAR). They reallocate energy into growing taller in an effort to harness sunlight, which results in stunted root growth and accelerated flowering time.

We’re not trying to be Dr. Frankenstein. We’ve been modifying genomes for 10,000 years.

“This comes at a tremendous cost,” explains Ullas Pedmale, an assistant professor at Cold Spring Harbor Laboratory, where his lab studies the interactions of plants and the environment. “This change in energy basically leads to lower crop and biomass yield. The plant is now like, ‘Hey, I’m stressed, I’ve got very limited light, so let me make my offspring or seeds as soon as possible,’ because now the plant is thinking about its Darwinian evolutionary pressure to increase reproduction as soon as possible.”

Understanding SAR is especially important as major food crops—such as wheat, corn, potato, and tomato—are shade avoiders. But what if there was a way to grow plants densely without sacrificing yield? By learning about the genes involved in shade avoidance, Pedmale thinks he can shut down the plant’s state of distress, and perhaps engineer plants that can access sunlight but not panic into flowering early and stunting root growth thereby reducing yield.

Pedmale has been researching how plants perceive and modify their architecture in response to light. Specifically, he is studying a group of proteins called cryptochromes, what he calls one of the eyes of the plant. Cryptochromes, the only group of receptors common among animals and plants, sense changes in the availability of blue light. A reduction in blue light or red light with an increase in far-red light indicates that a plant is in the shade, prompting it to switch on genes that, among other responses, stunt root growth. Understanding cryptochromes and their interplay with these genes could be an important aspect of mediating these responses and the key to growing crops at higher densities....