{"title":"MsbZIP55 regulates salinity tolerance by modulating melatonin biosynthesis in alfalfa","authors":"Tingting Wang, JiaQi Yang, JiaMin Cao, Qi Zhang, HuaYue Liu, Peng Li, YiZhi Huang, WenWu Qian, Xiaojing Bi, Hui Wang, Yunwei Zhang","doi":"10.1111/pbi.70035","DOIUrl":null,"url":null,"abstract":"SummarySoil salinity is a severe abiotic stress that damages plant growth and development. As an antioxidant and free radical scavenger, melatonin is well known for helping plants survive abiotic conditions, including salinity stress. Here, we report that the salt‐related gene <jats:italic>MsSNAT1</jats:italic>, encoding a rate‐limiting melatonin biosynthesis enzyme, is located in the chloroplast and contributes to salinity stress tolerance in alfalfa. We found that the <jats:italic>MsSNAT1</jats:italic> overexpressing alfalfa lines exhibited higher endogenous melatonin levels and increased tolerance to salt stress by promoting antioxidant systems and improving ion homeostasis. Furthermore, through a combination of transcriptome sequencing, dual‐luciferase assays and transgenic analysis, we identified that the basic leucine zipper (bZIP) transcription factor, MsbZIP55, is associated with salt response and <jats:italic>MsSNAT1</jats:italic> expression. EMSA analysis and ChIP‐qPCR uncovered that MsbZIP55 can recognize and directly bind to the <jats:italic>MsSNAT1</jats:italic> promoter <jats:italic>in vitro</jats:italic> and <jats:italic>in vivo</jats:italic>. MsbZIP55 acts as a negative regulator of <jats:italic>MsSNAT1</jats:italic> expression, thereby reducing melatonin biosynthesis. Morphological analysis revealed that overexpressing <jats:italic>MsbZIP55</jats:italic> conferred salt sensitivity to transgenic alfalfa through a higher Na<jats:sup>+</jats:sup>/K<jats:sup>+</jats:sup> ratio and lower antioxidant activities, which could be alleviated by applying exogenous melatonin. Silencing of <jats:italic>MsbZIP55</jats:italic> by RNA interference in alfalfa resulted in higher expression of <jats:italic>MsSNAT1</jats:italic> and promoted salt tolerance by enhancing the antioxidant system enzyme activities and ion homeostasis. Our findings indicate that the MsbZIP55‐MsSNAT1 module plays a crucial role in regulating melatonin biosynthesis in alfalfa while facilitating protection against salinity stress. These results shed light on the regulatory mechanism of melatonin biosynthesis related to the salinity stress response in alfalfa.","PeriodicalId":221,"journal":{"name":"Plant Biotechnology Journal","volume":"18 1","pages":""},"PeriodicalIF":10.1000,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Plant Biotechnology Journal","FirstCategoryId":"5","ListUrlMain":"https://doi.org/10.1111/pbi.70035","RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"BIOTECHNOLOGY & APPLIED MICROBIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
SummarySoil salinity is a severe abiotic stress that damages plant growth and development. As an antioxidant and free radical scavenger, melatonin is well known for helping plants survive abiotic conditions, including salinity stress. Here, we report that the salt‐related gene MsSNAT1, encoding a rate‐limiting melatonin biosynthesis enzyme, is located in the chloroplast and contributes to salinity stress tolerance in alfalfa. We found that the MsSNAT1 overexpressing alfalfa lines exhibited higher endogenous melatonin levels and increased tolerance to salt stress by promoting antioxidant systems and improving ion homeostasis. Furthermore, through a combination of transcriptome sequencing, dual‐luciferase assays and transgenic analysis, we identified that the basic leucine zipper (bZIP) transcription factor, MsbZIP55, is associated with salt response and MsSNAT1 expression. EMSA analysis and ChIP‐qPCR uncovered that MsbZIP55 can recognize and directly bind to the MsSNAT1 promoter in vitro and in vivo. MsbZIP55 acts as a negative regulator of MsSNAT1 expression, thereby reducing melatonin biosynthesis. Morphological analysis revealed that overexpressing MsbZIP55 conferred salt sensitivity to transgenic alfalfa through a higher Na+/K+ ratio and lower antioxidant activities, which could be alleviated by applying exogenous melatonin. Silencing of MsbZIP55 by RNA interference in alfalfa resulted in higher expression of MsSNAT1 and promoted salt tolerance by enhancing the antioxidant system enzyme activities and ion homeostasis. Our findings indicate that the MsbZIP55‐MsSNAT1 module plays a crucial role in regulating melatonin biosynthesis in alfalfa while facilitating protection against salinity stress. These results shed light on the regulatory mechanism of melatonin biosynthesis related to the salinity stress response in alfalfa.
期刊介绍:
Plant Biotechnology Journal aspires to publish original research and insightful reviews of high impact, authored by prominent researchers in applied plant science. The journal places a special emphasis on molecular plant sciences and their practical applications through plant biotechnology. Our goal is to establish a platform for showcasing significant advances in the field, encompassing curiosity-driven studies with potential applications, strategic research in plant biotechnology, scientific analysis of crucial issues for the beneficial utilization of plant sciences, and assessments of the performance of plant biotechnology products in practical applications.