Mechanism of gibberellin oxidases in regulating crop growth and stress resistance

Gibberellin is a core hormone regulating crop growth, development, and stress responses. Its homeostasis is mainly co-regulated by three types of 2-oxoglutarate-dependent dioxygenases: GA20-oxidase (GA20ox), GA3-oxidase (GA3ox), and GA2-oxidase (GA2ox). This article systematically reviews the biochemical characteristics, gene functions, and applications of these three enzymes in crop growth and development, stress response, and molecular design breeding. All three enzymes contain conserved 2OG-FeII_Oxy and DIOX_N domains and maintain the dynamic balance of bioactive GAs by specifically catalyzing key steps in gibberellin synthesis and degradation. Studies have shown that gibberellin oxidases participate deeply in multiple core processes of crop growth and development through spatiotemporal-specific expression, specifically manifested as: (1) regulating seed germination and grain weight, modulating internode elongation to shape plant architecture, adjusting tiller number and root system configuration, and playing a dual regulatory role in root nodule symbiotic nitrogen fixation in leguminous plants; (2) regulating flowering time, pollen development, and inflorescence structure during the reproductive stage, affecting crop reproduction and yield formation; (3) mediating the "growth-defense trade-off" by reducing bioactive GA levels to conserve energy and enhancing crop tolerance to salt-alkali stress, drought, and extreme temperatures. Looking ahead, precise regulation of gibberellin oxidases is expected to achieve coordinated improvements in multiple traits such as high yield, stress resistance, and quality in crops. However, challenges remain, including insufficient precision in regulation and limited depth in data mining. These challenges need to be addressed by integrating technologies such as tissue-specific promoters, gene editing, and AI tools to advance molecular design breeding.