Results of Husker research improve rice resistance to nighttime heat stress

LINCOLN, Nebraska – New genetic insights from Husker scientists may help rice producers maintain yields despite rising nighttime temperatures, which pose a growing threat to 21st century agriculture. The University of Nebraska-Lincoln project, funded by the National Science Foundation, has great potential to bolster the sustainability of one of the world's leading crops at a time of climate change and rising global demand.

A multi-year NSF grant of $5.78 million funded research by a team led by Harkamal WaliaProfessor of Agricultural Sciences and Horticulture, in collaboration with Arkansas State University and Kansas State University. The scientists focused on understanding the responses of rice and wheat to rising nighttime temperatures.

The researchers studied hundreds of rice varieties under field and greenhouse conditions and analyzed phenotypic conditions as well as a wide range of genetic details. They recently published their results. in the journal Plant Physiology.

The project identified varieties that can better cope with high nighttime heat temperatures. Most importantly, the researchers found that a particular gene, LOGL1, has a major impact on rice weight under nighttime heat stress. Reduced LOGL1 levels likely mean better grain weight and higher overall yield.

GENE EDITING

The finding suggests that if gene editing technology can be used to create a less active version of LOGL1, the rice will have greater nighttime heat tolerance and achieve the desired yield, said Walia, Heuermann Chair in Agronomy and faculty member of the Daugherty Water for Food Global Institute.

Given this promising potential for genome editing, UNL has filed a patent application for the LOGL1 technology with the U.S. Patent and Trademark Office. NUTech Ventures, the university's technology commercialization affiliate, is working to attract potential commercialization partners who can help bring the technology to market.

“Rice and wheat, together with maize, provide more than 60 percent of the calories consumed by humans,” Walia said.

There is a wealth of data on the agronomic impacts of daytime heat stress, but there are still major gaps to be filled regarding the consequences of nighttime heat stress.

“If you look at more than 100 years of data in the United States, it's clear that temperatures warm almost twice as fast at night as they do during the day,” Walia said.

The paper by Walia and colleagues states: “Field studies suggest that every one degree Celsius increase in average nighttime temperature during the growing season can lead to a reduction in rice crop yield of up to 10%.”

Two strategic investments by UNL in key scientific infrastructure were critical to securing the federal grant, funded through the NSF's Experimental Program to Stimulate Competitive Research (EPSCOR). The automated plant phenotyping facility at the Nebraska Innovation Campus Greenhouse was “instrumental” in conducting the detailed analysis necessary for the rice study, Walia said. And the university's Holland Computing Center enabled the required data analysis, data storage and software development.

Walia supervised Jaspreet Sandhu and Larissa Irvin, PhD students in the Department of Agronomy and Horticulture, in taking the LOGL1 discovery further. The team is pursuing the rice project by filling other gaps in scientific knowledge. A key focus is on understanding how the LOGL1 gene works and its impact on other important crops such as wheat and maize.

The Husker scientists also want to find an answer to a surprise that their research has produced: One of their gene edits to reduce the LOGL1 effect increased the rice's grain yield even though the plant was not even under stress.

“We're really interested in finding out why this is the case,” Walia said. “Is this something specific to this gene, or was something else changed during the experimental process of gene editing that resulted in higher grain weight?”