Guoyong Liu, Xiang Yu, Yonglun Zeng, Baiying Li, Rong Wang, Xiangfeng Wang, Xiaoyun Zhao, Liwen Jiang, Yan Guo
{"title":"SOS2-FREE1 regulates SOS1 tonoplast sorting to promote Na<sup>+</sup> compartmentalization in vacuole during salt stress response.","authors":"Guoyong Liu, Xiang Yu, Yonglun Zeng, Baiying Li, Rong Wang, Xiangfeng Wang, Xiaoyun Zhao, Liwen Jiang, Yan Guo","doi":"10.1111/jipb.13970","DOIUrl":null,"url":null,"abstract":"<p><p>Soil salinity significantly affects plant survival and limits crop productivity. Under salt stress, plants can transport sodium ions (Na<sup>+</sup>) out of cells and sequester them into vacuoles for detoxification. The salt excretion process is governed by the SALT OVERLY SENSITIVE (SOS) pathway, which involves the calcium sensors SOS3 and SOS3-LIKE CALCIUM BINDING PROTEIN 8, the protein kinase SOS2, and the plasma membrane Na<sup>+</sup>/H<sup>+</sup> antiporter SOS1. While previous studies have provided insights into Na<sup>+</sup> transport through the SOS system, the role of this pathway in Na<sup>+</sup> compartmentalization within vacuoles remains poorly understood. In this study, we demonstrate that SOS1 partially internalizes to the tonoplast under salt stress, which is crucial for Na<sup>+</sup> compartmentalization in vacuoles in Arabidopsis (Arabidopsis thaliana). We show that SOS2 phosphorylates the endosomal sorting complex required for transport-I (ESCRT-I) component FYVE DOMAIN PROTEIN REQUIRED FOR ENDOSOMAL SORTING 1 (FREE1), which disrupts its interaction with VPS23A, an ESCRT-I component. This phosphorylation event inhibits the formation of intraluminal vesicles (ILVs) in prevacuolar compartments and multivesicular bodies (PVCs/MVBs), thereby remodeling endosomal sorting during salt stress. Additionally, our previous research indicated that SOS2-mediated phosphorylation of FREE1 leads to vacuole fragmentation by altering endomembrane fusion, thereby regulating intracellular Na<sup>+</sup> homeostasis. Taken together, our findings reveal how the SOS2-FREE1 module orchestrates both endomembrane fusion and endosome sorting processes to enhance plant salt tolerance, providing novel insights into the cellular mechanisms underlying salt stress adaptation.</p>","PeriodicalId":195,"journal":{"name":"Journal of Integrative Plant Biology","volume":" ","pages":""},"PeriodicalIF":9.3000,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Integrative Plant Biology","FirstCategoryId":"99","ListUrlMain":"https://doi.org/10.1111/jipb.13970","RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"BIOCHEMISTRY & MOLECULAR BIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Soil salinity significantly affects plant survival and limits crop productivity. Under salt stress, plants can transport sodium ions (Na+) out of cells and sequester them into vacuoles for detoxification. The salt excretion process is governed by the SALT OVERLY SENSITIVE (SOS) pathway, which involves the calcium sensors SOS3 and SOS3-LIKE CALCIUM BINDING PROTEIN 8, the protein kinase SOS2, and the plasma membrane Na+/H+ antiporter SOS1. While previous studies have provided insights into Na+ transport through the SOS system, the role of this pathway in Na+ compartmentalization within vacuoles remains poorly understood. In this study, we demonstrate that SOS1 partially internalizes to the tonoplast under salt stress, which is crucial for Na+ compartmentalization in vacuoles in Arabidopsis (Arabidopsis thaliana). We show that SOS2 phosphorylates the endosomal sorting complex required for transport-I (ESCRT-I) component FYVE DOMAIN PROTEIN REQUIRED FOR ENDOSOMAL SORTING 1 (FREE1), which disrupts its interaction with VPS23A, an ESCRT-I component. This phosphorylation event inhibits the formation of intraluminal vesicles (ILVs) in prevacuolar compartments and multivesicular bodies (PVCs/MVBs), thereby remodeling endosomal sorting during salt stress. Additionally, our previous research indicated that SOS2-mediated phosphorylation of FREE1 leads to vacuole fragmentation by altering endomembrane fusion, thereby regulating intracellular Na+ homeostasis. Taken together, our findings reveal how the SOS2-FREE1 module orchestrates both endomembrane fusion and endosome sorting processes to enhance plant salt tolerance, providing novel insights into the cellular mechanisms underlying salt stress adaptation.
期刊介绍:
Journal of Integrative Plant Biology is a leading academic journal reporting on the latest discoveries in plant biology.Enjoy the latest news and developments in the field, understand new and improved methods and research tools, and explore basic biological questions through reproducible experimental design, using genetic, biochemical, cell and molecular biological methods, and statistical analyses.