Significant Advances in Plant Metabolism

Researchers have had quite impressive results with plants that possess all the genes necessary for the McG cycle. These plants exhibited weights between two to three times greater than control plants, which only had a subset of those genes. They not only had more leaves, but those leaves were also larger, and the plants produced a greater number of seeds. In various growing environments, the plants with a complete McG cycle absorbed more carbon without increasing their water intake.

The outcome of having a two-carbon output was also in line with expectations. By using radioactive bicarbonate, the team could track the presence of carbon in specific molecules. Imaging techniques showed that the plants generated such a large amount of lipids that their cells developed internal pockets filled solely with fatty substances. Triglyceride levels surged by factors exceeding 100.

Overall, the plants clearly performed better with this additional carbon fixation pathway. However, there are several warnings to consider. For one, it’s uncertain if findings from this small weed will be applicable to larger plants or crops, or any species beyond Arabidopsis for that matter. It’s possible that having excess fat globules in the cells could have repercussions, especially for something larger like a tree. Additionally, plants grown in laboratory settings often thrive in nutrient-rich soil, raising questions about how this might translate in varied real-world conditions.

Moreover, we still don’t know if the extra carbon these plants are grabbing from the atmosphere would be stored in a meaningful way. It’s plausible that, upon dying, the fat could simply be oxidized. Still, there are many methods for crafting biofuels that depend on tweaking the fats found in plants or algae. There’s potential for this research to enhance biofuel efficiency, potentially leading to positive climate effects.

Regardless of the practical implications, it’s pretty remarkable that we’ve reached a stage where we can fundamentally alter a metabolic pathway that has functioned for billions of years, all without drastically harming the plants.

Science, 2025. DOI: 10.1126/science.adp3528