The ethylene biosynthesis enzyme ACS3 acts as a key regulator of grain yield in rice

Enhancing rice yield per unit area is one of the most effective approaches to addressing the global food crisis. However, yield improvement is often accompanied by reduced stress resistance, making it imperative to balance productivity and resilience in current rice breeding efforts. Recent studies highlight phytohormone regulation as a promising strategy to achieve this balance. Ethylene, a hormone unique to plants, plays crucial roles in regulating rice growth, development, and stress responses, yet its role in coordinating grain yield and stress resistance remains unclear. In this study, we found that 1-aminocyclopropane-1-carboxylic acid synthase 3 (ACS3), a key rate-limiting enzyme in ethylene biosynthesis, was highly expressed in panicles and tiller buds, and that loss-of-function reduced ethylene levels. Furthermore, acs3 mutant significantly increased the number of productive panicles and grains per panicle, resulting in enhanced rice yield. Notably, the acs3 mutant exhibited enhanced yield per plant without significant reduction in stress resistance. These findings suggest that fine-tuning ethylene homeostasis via ACS3 rebalances growth and stress adaptation, offering a potential novel strategy for high-yield rice breeding with sustained stress tolerance.

The online version contains supplementary material available at 10.1007/s11032-025-01613-w.