赤霉素氧化酶调控作物生长与抗逆的作用机制

Mechanism of gibberellin oxidases in regulating crop growth and stress resistance

  • 摘要: 赤霉素是调控作物生长发育与抗逆响应的核心激素,其稳态平衡主要由GA20-氧化酶(GA20ox)、GA3-氧化酶(GA3ox)和GA2-氧化酶(GA2ox)三类2-酮戊二酸依赖性双加氧酶协同调控。本文系统综述了这三类酶的生化特征、基因功能及其在作物生长发育、抗逆响应和分子设计育种中的应用。这三类酶均含保守的2OG-FeII_Oxy和DIOX_N结构域,通过特异性催化赤霉素合成与降解的关键步骤,维持体内活性GA的动态平衡。研究表明,赤霉素氧化酶通过时空特异性表达,深度参与作物生长发育的多个核心过程,具体表现为:(1)调控种子萌发与粒重、调节节间伸长以塑造株型、调节分蘖数与根系构型,且在豆科植物根瘤共生固氮中发挥双重调控作用;(2)调控生殖阶段的开花时间、花粉发育及花序结构,影响作物繁殖与产量形成;(3)通过介导“生长-防御权衡”,降低活性GA水平以节约能量,增强作物对盐碱、干旱、极端温度的耐受性。展望未来,精准调控赤霉素氧化酶有望实现作物高产、抗逆、优质的多性状协同改良,但仍面临调控精准度不足与数据挖掘深度不够的挑战,需结合组织特异性启动子、基因编辑及AI工具等技术推动分子设计育种升级。

     

    Abstract: 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.

     

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