Gene Editing Boosts Rice Grain Quality and Resilience to Heat Stress, Finds Study

As global temperatures continue to rise, the impact on crop quality and productivity is becoming increasingly evident. Among the affected crops, rice stands out as one of the most vulnerable to heat stress during the ripening phase, leading to a detrimental condition known as "chalkiness." However, a recent breakthrough by researchers from the University of Arkansas and the University of Arkansas System Division of Agriculture (UADA) has paved the way for a potential solution to this problem.

Chalkiness in rice refers to the loosening of rice granules due to reduced starch concentration. This issue can lead to decreased milling yields, cooking quality, and overall market value of the crop. To address this concern, the team of researchers turned to gene-editing technology and published their findings in the Plant Journal in a paper titled "Targeted mutagenesis of the vacuolar H+ translocating pyrophosphatase gene reduces grain chalkiness in rice."

The researchers focused their efforts on a specific gene responsible for encoding the vacuolar H+ translocating pyrophosphatase (V-PPase) enzyme. This enzyme has been known to play a significant role in increasing grain chalkiness when expressed at high levels. By employing the revolutionary CRISPR-Cas9 gene-editing technology, the scientists successfully reduced the expression of V-PPase by editing a promoter element that regulates its activity.

The results of their experiment were promising. The modified rice strains exhibited a remarkable 7 to 15 fold decrease in chalkiness, depending on the rice variety. Additionally, the mutated lines displayed an increase in grain weight. Even under elevated nighttime temperatures, the positive effects persisted, demonstrating the newfound heat resistance of the rice strains.

The most noticeable improvement in the modified rice strains was the compact packing of starch granules and the formation of translucent, high-quality rice grains instead of chalky ones. This shift in grain characteristics represents a significant advancement in rice quality, providing hope for a more resilient and high-yielding rice crop in the face of climate change.

The significance of this achievement has been recognized by the scientific community, and the paper's lead author, Peter James Icalia Gann, a Fulbright Scholar in the Cell and Molecular Biology Program, along with co-author Vibha Srivastava, a professor in the Department of Crop, Soil, and Environmental Sciences with a joint appointment at U of A and UADA, have filed for a provisional patent for their novel gene-editing approach.

Peter James Icalia Gann expressed the importance of finding solutions for food systems affected by rising temperatures to sustain life on our planet. He emphasized the team's excitement in sharing their findings, showcasing how gene-editing can improve rice grain quality and maintain consistency, even under heat stress.

The collaborative research also involved additional co-authors, including Dominic Dharwadker, an honors student in chemistry and biochemistry at the U of A, and Sajedeh Rezaei Cherati, Kari Vinznat, and Mariya Khodakovskaya from the Department of Biology at the University of Arkansas, Little Rock.