New plans to save the most important grain in the world

Rice plants submerged as part of the long-running investigation into root responses. Credit: Julia Bailey-Serres/UCR

Plants are just like us, but they have their own ways to deal with stress. Scientists are trying to figure out how plants deal with stress so they can protect one of the most important crops on Earth from extreme changes in the weather.

A team from UC Riverside has learned what happens to the roots of rice plants when they are stressed by either too much water or not enough water. New ways to keep people safe are based on these observations.

“This one crop provides up to 45 percent of the world’s calories, but its harvests are in danger,” said Julia Bailey-Serres, a geneticist at UCR and the study’s lead author. “Each year in the U.S., floods cause as much damage to farmers’ crops as droughts.”

Rice can grow in flooded soils, but if the water stays too deep for too long, the plants will produce less food or even die. This work simulated floods that lasted for five days or longer and covered all of the plants. It also made it look like there was a drought.

In particular, the researchers looked at how both floods and droughts affected the roots, since roots are the first parts of a plant to react to stress.

In a new paper in the journal Developmental Cell, they talk about their work.

One important fact is that rice roots make a cork-like substance called suberin when they are stressed. It helps protect against both floods and droughts.

Bailey-Serres said, “Suberin is a lipid molecule that helps water from the roots get to the shoots and oxygen from the shoots get to the roots.” “Rice has a better chance of surviving in all kinds of weather if we help the plant make more suberin.”

The researchers were able to find a network of genes that control the production of suberin. They can use this information to edit genes or choose which plants to grow.

“It’s exciting to learn about suberin because soil microbes can’t break it down,” said Alex Borowsky, a computational biologist at UCR and co-author of the study. “This means that the carbon that the plant puts into suberin molecules in its roots stays in the ground.” This means that adding more suberin could help fight climate change by taking carbon out of the air and storing it.

The researchers also found the genes that control some of the other things rice does when it is stressed.

Bailey-Serres said, “One interesting thing we found is that when rice plants are submerged in water, the root cell growth cycle stops. It starts up again soon after the shoots get access to air.”

In the future, the research team wants to see if changing these stress responses can make the plant more resistant to both wet and dry conditions.

“Now that we know how these responses work, we have a plan for how to change the rice genome in a way that will make the plant more resistant to stress,” Bailey-Serres said.

Even though both heavy rains and droughts are becoming more of a problem, Bailey-Serres is hopeful that new genetic technology can make it stronger before it’s too late.

“It’s amazing that we can make a small but specific change to a plant’s genome and protect it from disease. Even though our crops are at risk, new technologies give us hope “Bailey-Serres said that.

Further information: Mauricio A. Reynoso et al, Gene regulatory networks shape developmental plasticity of root cell types under water extremes in rice, Developmental Cell (2022). DOI: 10.1016/j.devcel.2022.04.013

Journal information: Developmental Cell

Source: University of California – Riverside