Mutant Rice Plants with Low Gibberellin Produce High Yield and Stress Tolerance

One of the main challenges of modern agricultural biotechnology is maximizing plant architecture to enhance productivity, stress tolerance, and water use efficiency. Gibberelins (GAs) are known to regulate plant height and tillering which are directly linked to grain yield in cereals. To optimize these traits, the team of Shuen-Fang Lo from Academia Sinica and National Chung Hsing University in Taiwan eased the levels of GAs in rice thru degradation.

GA 2-oxidase (GA2ox) is a key enzyme that inactivates endogenous GAs and their precursors. The team focused on GA2ox6, which is known to regulate the architecture and function of rice plants. The team then mutated nine specific amino acids in this domain and observed a gradient of effects.

Expression of the GA2ox6 non-functioning mutants moderately lowered GA levels, leading to reduced plant height, more productive tillers, expanded root system, higher WUE and photosynthesis rate, and enhanced abiotic and biotic stress tolerance in transgenic rice. Combinations of these traits resulted in not only drought and disease tolerance, but also increased grain yield in field trials.

This study holds the potential of manipulating GA levels to improve plant architecture, stress tolerance, and grain yield in rice and possibly in other crops.

For more on this promising study, read the full article in Plant Biotechnology Journal.