质膜Na^(+)/H^(+)逆向转运蛋白SOS1在植物离子稳态平衡中的作用

Roles of Plasma Membrane Na^(+)/H^(+)Antiporter SOS1 in Maintaining Ionic Homeostasis of Plants

植物通过一系列复杂转运系统调节离子稳态以适应盐渍环境,SOS(salt overly sensitive)信号通路是植物响应非生物胁迫的主要信号途径,主要由质膜Na^(+)/H^(+)逆向转运蛋白SOS1、丝氨酸/苏氨酸类蛋白激酶SOS2和钙感应器SOS3组成。SOS1作为SOS信号通路的主要成员之一,广泛存在于高等植物中,由于早期的进化差异,可能导致不同物种SOS1的结构和理化性质存在一定的特异性。SOS1蛋白为一个同型二聚体,每个单体由跨膜和胞内结构域组成,这为整合来自不同途径的信号和调节Na^(+)转运提供了稳定的对接平台。SOS1基因转录水平受到不同胁迫条件的调控,通过Ca^(2+)信号调控、磷酸化、自抑制和与离子转运体协同调控等机制可抑制或激活SOS1活性。该蛋白具有调控植物昼夜节律和pH以及维持离子稳态等功能,在植物逆境胁迫响应中发挥重要作用。论文对SOS1的结构、功能、调控机制及其维持植物离子稳态平衡作用等方面的研究进展加以综述,并对其未来研究方向进行展望,以期为农作物抗逆性遗传改良提供理论支持和优异基因资源。

Plants regulate ion homeostasis to adapt to saline environment through a series of complex transport systems.SOS(salt over sensitive)signal pathway is the major signal pathway for plants to respond to abiotic stress,which is mainly composed of plasma membrane Na^(+)/H^(+)antiporter SOS1,serine/threonine protein kinase SOS2,and calcium sensor SOS3.As one of the main members of SOS signaling pathway,SOS1 widely exists in higher plants.Due to the early evolutionary differences,the structural,physical,and chemical properties of SOS1 from different species had certain specificity.The SOS1 protein is a homodimer,and each monomer is composed of transmembrane and intracellular domains,which provides a stable docking platform for integrating signals from different pathways and regulating Na^(+)transport.Transcription level of the SOS1 gene was regulated by different stress conditions.SOS1 activity was inhibited or activated through Ca^(2+)signal regulation,phosphorylation,self-inhibition,and synergistic regulation with other ion transporters.SOS1 has shown to regulate circadian rhythm and pH,and maintain ion homeostasis in plants,which plays an important role in the response of plant to abiotic stress.In this review,the structure,function,regulation mechanism of SOS1 and its role in maintaining plant ion homeostasis are reviewed,and its future research direction is also prospected.The information in this review provide a theoretical support and excellent genetic resources for the genetic improvement of crops to produce new,stress-resistant varieties.