As global temperatures continue to rise, maintaining the quality and yield of cold-adapted crops will increasingly become a challenge. One crop known to be affected by higher nighttime temperatures during the ripening stage is rice, which exhibits a condition known as "chalkiness" due to heat stress.
Chalky refers to rice grains that are less dense due to the reduced concentration of starch. This can lead to lower grind yields, cooking quality and overall market value.
Researchers at the University of Arkansas and the University of Arkansas Division of Agricultural Systems (UADA) have published a new paper in The Plant Journal that may offer a remedy for thermally induced and genetic chalk. The paper, "Targeted mutagenesis of the vacuolar H+ translocation pyrophosphatase gene reduces grain chalkiness in rice," details how the team was able to gene-edit a japonica species to reduce chalkiness.
The researchers specifically targeted a gene encoding vacuolar H+ translocation pyrophosphatase (V-PPase), an enzyme that plays a role in increasing grain chalkiness. Using CRISPR-Cas9 gene editing technology, the team was able to reduce the expression of V-PPase by editing the promoter element, which controls the amount of V-PPase expressed.
Mutant rice lines exhibited 7-15 times less chalkiness, depending on the rice line, resulting in increased kernel weight. The findings held even with elevated nighttime temperatures. Overall, the mutant lines were characterized by more compact packing of starch granules, resulting in translucent (rather than chalky) rice, showing a clear improvement in rice quality.
The paper's first author, Peter James Ikaria Gann, is a Fulbright Scholar in the Cell and Molecular Biology Program.
"If we want to sustain life on Earth, it's critically important to find solutions to the food system problems that arise as average temperatures rise," Gann said. "We're excited to share our findings, which uses gene editing in rice to improve grain quality, which remains consistent even under heat stress."
Other co-authors include Dominic Dharwadker, a chemistry and biochemistry honors student at the University of Arizona, and Sajedeh Rezaei Cherati, Kari Vinznat and Mariya Khodakovskaya from the Department of Biology at the University of Arkansas in Little Rock.
Gann and Dharwadker have previously received awards from the Society for In Vitro Biology and the American Society of Plant Biologists for related work.
Reading Background
Gene editing technology in plant protection
Plant protection can benefit from gene editing technologies in a variety of ways. CRISPR/Cas9, TALEN, and ZFN-based gene editing technologies, for example, play an important role in breeding plants for disease resistance and resistance to environmental stresses.
For instance, the OsERF922 and OsSEC3A genes in rice have been disrupted using CRISPR/Cas9-based gene editing to create resistance to rice blast disease, and ZFN-based gene editing has been applied to maize to create herbicide resistance in maize.
Gene Editing Technology at Lifeasible
Lifeasible supports the use of gene editing for plant protection and offers a range of gene editing services. We primarily offer gene editing services for plants in order to produce plant varieties that are resistant to abiotic stress and diseases. By using CRISPR/Cas9, TALEN, and ZFN-based gene editing technologies, we can achieve precision plant gene editing. For the protection of plants, we also offer microbial and pest gene editing.
