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Study identifies gene that may reduce chalkiness of heat-stressed rice

Study IDs gene that may reduce chalkiness of heat-stressed rice
Nebraska's Harkamal Walia, professor of agronomy and horticulture. Credit: University of Nebraska-Lincoln

Oppressive temperatures can curb the growth and yields of multiple cereal crops, including rice, which is eaten by some 3.5 billion people worldwide. Though much of the research into heat stress has investigated its effects on quantity, it can degrade grain quality, too. Heat stress is especially known for introducing chalkiness to the interior of a rice seed, which, by complicating the milling process and making the grain less palatable to consumers, also lowers its market price.

Still, researchers know less about the genetic contributors to that stress-driven chalkiness—and how to counteract it—than they do yield and other outcomes.

Nebraska's Harkamal Walia and colleagues recently aimed to both identify linked with chalkiness and determine a faster, more efficient way to compare that chalkiness among different varieties of . The researchers began by exposing 229 genetically diverse rice plants to for five days, then collected and scanned grains from each of those plants.

With the aid of SeedExtractor, a Husker-developed imagery analysis program, the team found that the ratio of red vs. green wavelengths reflected from the seeds could help estimate the amount of chalkiness within. Their work is published in the journal Frontiers in Plant Science.

After incorporating that red-green ratio into a genetic analysis of the rice plants, the team pinpointed one particular gene, OsCG5, that seemed especially active in the face of heat stress. The number of proteins originating from OsCG5—a measure of —rose sharply not long after the researchers turned up the heat. That rise in gene expression also correlated with less chalkiness in the stressed rice seeds. Rice plants lacking OsCG5, meanwhile, responded to heat stress with more chalkiness than did plants containing the gene. Seeds from the OsCG5-absent plants grew 11–17% shorter, too.

Learning more about OsCG5 could inform the development of rice varieties that yield less-chalky seeds amid the heat waves of a still-warming planet, the researchers said. Incorporating the team's red-green pixel analysis might also speed the identification of other chalk-relevant genes in rice and related cereal crops.

More information: Anil Kumar Nalini Chandran et al, Rice Chalky Grain 5 regulates natural variation for grain quality under heat stress, Frontiers in Plant Science (2022). DOI: 10.3389/fpls.2022.1026472

Journal information: Frontiers in Plant Science

Citation: Study identifies gene that may reduce chalkiness of heat-stressed rice (2023, January 10) retrieved 30 March 2023 from
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