Husker findings boost rice’s ability to withstand nighttime heat stress

New genetic findings by Husker scientists can help rice producers maintain yield in the face of increased nighttime temperatures, a growing threat for 21st century agriculture. The University of Nebraska–Lincoln project, funded by the National Science Foundation, has major potential to strengthen the sustainability of one of the planet’s leading crops at a time of climate stress and increasing global demand. 

A multi-year, $5.78 million NSF grant funded the research of a team led by Harkamal Walia, professor of agronomy and horticulture, in collaboration with Arkansas State University and Kansas State University. The scientists focused on understanding the responses of rice and wheat to increases in nighttime temperature. 

The researchers studied hundreds of rice varieties under field and greenhouse settings, analyzing phenotype conditions and a wide range of genetic details. They recently published their findings in the journal Plant Physiology. 

The project identified varieties that cope better with high nighttime heat temperatures. Above all, the researchers found that a specific gene, LOGL1, has major influence on rice weight under nighttime heat stress. A reduced level of LOGL1 is likely to mean better grain weight and overall yield. 

The finding indicates that if gene-editing technology can produce a less active version of LOGL1, the rice will exhibit greater nighttime heat tolerance and maintain desired yield, said Walia, the Heuermann Chair of Agronomy and a faculty fellow with the Daugherty Water for Food Global Institute. 

Given this promising gene-editing potential, UNL has a patent application for LOGL1 technology pending with the U.S. Patent and Trademark Office. NUTech Ventures, the university’s technology commercialization affiliate, is working to engage with potential commercialization partners that can help bring the technology to the market. 

“Rice and wheat, along with corn, collectively provide more than 60% of calories consumed by humans,” Walia said.

Data are plentiful concerning agronomic effects from daytime heat stress, but major gaps need to be filled about ramifications from nighttime heat stress. 

“If you look at more than 100 years’ worth of data in the U.S., the nights are warming at nearly twice the rate of the daytime,” Walia said. 

The paper by Walia and colleagues notes that “field studies indicate that every one-degree Celsius increase in average nighttime temperature during the growing season can cause up to 10% reduction in rice yield.”

Two strategic investments in major scientific infrastructure by UNL were crucial to securing the federal grant, which was funded through the NSF’s Experimental Program to Stimulate Competitive Research, or EPSCoR. The automated plant phenotyping facility at the Nebraska Innovation Campus Greenhouse was “instrumental” in facilitating the detailed analysis necessary for the rice study, Walia said. And the university’s Holland Computing Center made possible the required data analytics, data storage and software development. 

Walia mentored Jaspreet Sandhu and Larissa Irvin, graduate students in the Department of Agronomy and Horticulture, to pursue the LOGL1 discovery. The team continues to follow up the rice project by filling in additional gaps in the scientific knowledge. A central focus is understanding how the LOGL1 gene works and what other impacts it has on other major crops such as wheat and corn. 

The Husker scientists also want to find the answer to a surprise their research produced: One of their gene edits to reduce the LOGL1 effect increased the rice’s grain yield when the plant wasn’t even stressed. 

“So, we're really interested in discovering why that is the case,” Walia said. “Is this something specific to this gene, or is there something else that was altered during the gene-editing experimental process, resulting in higher grain weight?”