A team from the Innovative Genomics Institute at the University of California, Berkeley (UCB) has managed to increase gene expression in a food crop by modifying its upstream regulatory DNA. This groundbreaking research, published in Science Advances, marks the first time an unbiased gene-editing approach has been utilized to boost gene expression and downstream photosynthetic activity in crops. While previous studies have focused on using CRISPR/Cas9 gene-editing to decrease gene expression, this new research demonstrates the potential for fine-tuning gene expression in crops to enhance desired traits.
The research team, led by Dhruv Patel-Tupper, was inspired by previous work that had successfully increased the water-use efficiency of a model crop by overexpressing the PsbS gene, which is involved in the photoprotection process. By utilizing genes that are naturally found in plants, the researchers aimed to improve the expression of a plant’s native genes without introducing foreign DNA. The target crop for this study was rice, which provides a significant portion of the world’s calories and has a limited number of key photoprotection genes, making it an ideal model system for gene-editing experiments.
This work was conducted as part of the Realizing Increased Photosynthetic Efficiency (RIPE) project, which aims to enhance global food production by developing crops that can convert solar energy into food more efficiently. By leveraging CRISPR/Cas9 to modify the regulatory DNA upstream of the target gene, the team was able to significantly increase gene expression and downstream activity in rice plants. Surprisingly, the changes in DNA had a larger impact on gene expression than anticipated, demonstrating the remarkable plasticity of plants to undergo genetic modifications.
Through RNA sequencing experiments, the researchers observed that inversions in the regulatory DNA led to increased gene expression of PsbS. Importantly, the modifications did not compromise the activity of other essential genes in the rice genome, indicating that the approach was highly targeted and effective. While the team was able to demonstrate the feasibility of this method, they noted that only around 1% of the generated plants exhibited the desired trait, highlighting the challenges and limitations of this gene-editing approach.
Despite the challenges, the researchers believe that this approach holds promise for accelerating the breeding of crops with improved traits. By utilizing CRISPR/Cas9 to modify existing genes rather than introducing foreign DNA, they aim to overcome regulatory hurdles and expedite the development of crops that can adapt to climate change and grow more efficiently. While the process may be more complex than traditional breeding methods, the potential benefits of this gene-editing approach in enhancing crop productivity and resilience make it a valuable tool for future agricultural research and development.
