PDF(Pubmed)
Abstract：
Unfavourable conditions, such as prolonged drought and high salinity, pose a threat to the survival and agricultural yield of plants. The phytohormone ABA plays a key role in the regulation of plant stress adaptation and is often maintained at high levels for extended periods. While much is known about ABA signal perception and activation in the early signalling stage, the molecular mechanism underlying desensitization of ABA signalling remains largely unknown. Here we demonstrate that in the endoplasmic reticulum (ER)-Golgi network, the key regulators of ABA signalling, SnRK2.2/2.3, undergo N-glycosylation, which promotes their redistribution from the nucleus to the peroxisomes in Arabidopsis roots and influences the transcriptional response in the nucleus during prolonged ABA signalling. On the peroxisomal membrane, SnRK2s can interact with glucose-6-phosphate (G6P)/phosphate translocator 1 (GPT1) to maintain NADPH homeostasis through increased activity of the peroxisomal oxidative pentose phosphate pathway (OPPP). The resulting maintenance of NADPH is essential for the modulation of hydrogen peroxide (H2O2) accumulation, thereby relieving ABA-induced root growth inhibition. The subcellular dynamics of SnRK2s, mediated by N-glycosylation suggest that ABA responses transition from transcriptional regulation in the nucleus to metabolic processes in the peroxisomes, aiding plants in adapting to long-term environmental stress.
摘要：
不利条件,如长期干旱和高盐度，对植物的生存和农业产量构成威胁。植物激素ABA在植物胁迫适应的调节中起着关键作用，并且通常长时间维持在高水平。虽然人们对早期信号传导阶段的ABA信号感知和激活了解很多，ABA信号脱敏的分子机制仍然未知。在这里，我们证明在内质网（ER）-高尔基网络中，ABA信号的关键调节剂，SnRK2.2/2.3，进行N-糖基化，促进它们从拟南芥根中的核重新分布到过氧化物酶体，并在延长的ABA信号传导过程中影响核中的转录反应。在过氧化物酶体膜上，SnRK2s可以与葡萄糖-6-磷酸（G6P）/磷酸盐转运蛋白1（GPT1）相互作用，通过增加过氧化物酶体氧化戊糖磷酸途径（OPPP）的活性来维持NADPH稳态。所产生的NADPH的维持对于过氧化氢（H2O2）积累的调制至关重要，从而减轻ABA诱导的根生长抑制。SnRK2s的亚细胞动力学，由N-糖基化介导，表明ABA反应从细胞核中的转录调节过渡到过氧化物酶体中的代谢过程，帮助植物适应长期的环境压力。
