白颖苔草盐诱导关键代谢物质筛选及其分子调控机制的研究

Salt stress is a major abiotic factor that limits the growth of many plant species. The domestic perennial Carex rigescens, which is characterized by low height and the robust tolerance to salt, drought, and heat, is an important native low-maintenance turfgrass for soil and water conservation, for urban as well as rural greening in the saline-alkali areas of northern China. Analysis of the changes of key metabolites and their metabolic pathway in Carex rigescens under salt stress is of great value in exploring the molecular mechanism of salinity-induced salt-tolerance responses in Carex rigescens. Our study conducts comparative analysis of the metabolism between the leaves/roots that are salt-treated and the leaves/roots that are not salt-treated in two kinds of C. rigescens (salt-tolerant and salt-sensitive). We use UHPLC-Q-TOF/MS approaches to identify the important salt-tolerance metabolites and pathways. Further studies of the molecular mechanisms and the function of key metabolite of the regulatory genes are achieved by assays of exogenous application, forward and reverse genetic analysis, and transcript expression profiling detection. Through these ways, we explore the salt-tolerance mechanism of C. rigescens. The results not only provide a new theoretical basis for the breeding of salt-tolerant new varieties of C. rigescens, they also have important significance for the practice of genetic improvement of other turfgrasses towards salt-tolerance.

盐碱是限制植物生长发育的主要非生物胁迫因素之一。乡土多年生白颖苔草具有植株低矮、耐盐碱、抗旱、耐热等特点，是我国北方盐碱地区重要的水土保持与城乡绿化低养护草坪草种。分析白颖苔草盐胁迫下关键代谢物质变化及代谢通路，对探索白颖苔草盐诱导耐盐应答的分子机制具有重要价值。本研究以耐盐与敏盐两种白颖苔草为材料，基于超高效液相色谱-四级杆-飞行时间串联质谱（UHPLC-Q-TOF/MS）技术，对盐胁迫下处理和未处理的白颖苔草叶片及根的代谢组进行比较分析，筛选其重要代谢物质和路径。利用外源施加、正反向遗传分析、转录水平表达分析等方法对关键代谢物质及其调控基因进行进一步的功能验证与分子机制的研究，探究其耐盐机制。研究结果不仅为白颖苔草耐盐的新品种选育提供新的理论依据，也将对草坪植物耐盐遗传改良实践具有重要意义。

盐碱是限制植物生长发育主要非生物胁迫因素之一。白颖苔草具有植株低矮 、耐盐碱、抗旱等特点，是我国北方重要的生态修复和城乡绿化低养护草种。分析白颖苔草盐胁迫下关键代谢物质变化及代谢通路，对探索白颖苔草盐诱导耐盐应答的分子机制具有重要价值。本研究以耐（黄骅）敏（北京）盐两白颖苔草为材料，对盐胁迫下白颖苔草叶片及根代谢组比较分析，筛选其重要代谢物质。利用外源施加、转录水平表达分析等方法对关键代谢物质及其调控基因进行功能验证与分子机制的研究，探究其耐盐机制。结果表明：白颖苔草代谢组盐处理适宜浓度为300mMNaCl；动态表达分析得出两材料分别鉴定到5764和10752个差异基因，构建了具显著性模型2个；差异基因GO注释和KEGG分析，生物进程分类中主要是代谢相关进程和蛋白代谢进程。分子功能分类中是催化活性和氧化还原酶活性。KEGG发现苯丙素代谢及氮代谢途径、亚麻酸代谢、淀粉和蔗糖代谢以及类胡萝卜素合成途径在两白颖苔草中均有较高的富集。差异基因功能鉴定到51个共同表达的转录因子、28个碳水化合物代谢相关基因，包括淀粉和蔗糖代谢途径中的多个催化酶类。盐胁迫后期鉴定到31个与植物激素信号转导相关的共同表达差异基因。细胞壁代谢通路中共鉴定18个共同表达的差异基因。利用qRT-PCR对其基因表达量进行分析并验证转录组数据是准确的。已初步明确乙酸合成关键基因 CrPDC1、咖啡酸氧甲基转移酶 CrCOMT基因和糖基转移酶CrUGT87A1基因的耐盐调控机理，均很好地提高植物的耐盐性。外源施加乙酸可提高盐胁迫下白颖苔草的耐盐性，其通过降低脂毒性提高植物耐盐性。研究结果为草耐盐新品种选育提供理论依据，也将对植物耐盐遗传改良具有重要的实际意义。已发表学术论文7篇，其中SCI 6篇，中文核心1篇。培养毕业博士1名，硕士1名，博士后出站1名。

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