Data Sheet 2_Salt stress enhances bioactive compound accumulation in Glycyrrhiza inflata: integrated transcriptomics and physiological analysis reveals germplasm-specific adaptation mechanisms.pdf

IntroductionGlycyrrhiza inflata Batal., a halophytic plant predominantly found in the saline-alkali deserts of southern Xinjiang, China, is renowned for its abundance of bioactive compounds like flavonoids and triterpenoids. It demonstrates considerable potential for applications within the pharmaceutical, food, health product, and cosmetic industries. Additionally, its cultivation presents the dual advantage of generating economic returns and facilitating the remediation of saline-alkali soils.
MethodsThis study examined 29 distinct provenances of G. inflata collected from various locations across Xinjiang. Key agronomic traits and the content of bioactive compounds in the underground parts of one-year-old plants grown in severely saline-alkali soil were measured to assess inter-germplasm variation. Subsequently, four germplasms displaying contrasting quality and salt tolerance were selected for controlled salt stress treatment (150 mM NaCl) under laboratory conditions. The effects on seed germination, root bioactive compound content, endogenous hormone levels, and key physiological and biochemical indices were analyzed. An integrated analysis of salt stress transcriptomic data was conducted using Weighted Gene Co-expression Network Analysis (WGCNA). This involved expression clustering and enrichment analysis of differentially expressed genes (DEGs) to investigate the impact of salt stress on genes related to bioactive compound biosynthesis (particularly flavonoids), endogenous hormone pathways, and key flavonoid biosynthesis enzymes.
ResultsThe findings indicate that germplasms with superior stress tolerance maintained higher and more stable levels of antioxidant enzymes. In response to stress, these resilient germplasms modulated hormone signaling, notably upregulating abscisic acid (ABA) and downregulating auxin (IAA), thereby reallocating resources towards defense mechanisms. Crucially, salt stress was identified as an effective means to enhance the accumulation of bioactive compounds in G. inflata. Transcriptomic analysis revealed substantial divergence in post-stress gene expression patterns among germplasms, implicating key pathways such as plant hormone signal transduction, flavonoid biosynthesis, and phenylpropanoid metabolism.
DiscussionThis research establishes a foundation for breeding high-quality G. inflata germplasms adapted to desert saline-alkali environments and provides valuable insights into the molecular mechanisms regulating the synthesis and accumulation of its valuable bioactive compounds.

引言：胀果甘草（Glycyrrhiza inflata Batal.）是一种盐生植物，主要分布于中国新疆南部的盐碱荒漠地带，因其富含黄酮类、三萜类等生物活性成分而闻名，在医药、食品、保健品及化妆品行业具有可观的应用潜力。此外，其种植兼具经济效益与盐碱地修复的双重优势。
方法：本研究采集了新疆各地的29份不同种源的胀果甘草材料。针对在重度盐碱土壤中种植的一年生植株地下部分的主要农艺性状及生物活性成分含量进行测定，以评估不同种质间的变异情况。随后选取品质与耐盐性差异显著的4份种质，在实验室条件下开展150 mM NaCl的可控盐胁迫处理，分析盐胁迫对种子萌发、根系生物活性成分含量、内源激素水平及关键生理生化指标的影响。采用加权基因共表达网络分析（Weighted Gene Co-expression Network Analysis, WGCNA）对盐胁迫转录组数据进行整合分析，通过对差异表达基因（differentially expressed genes, DEGs）进行表达聚类与富集分析，探究盐胁迫对与生物活性成分生物合成（尤其黄酮类）、内源激素通路及关键黄酮类生物合成酶相关基因的调控作用。
结果：研究结果表明，耐胁迫能力优异的种质可维持更高且更稳定的抗氧化酶活性水平。面对胁迫时，这类抗性种质会调控激素信号通路，显著上调脱落酸（abscisic acid, ABA）的表达并下调生长素（auxin, IAA）的水平，从而将资源重新分配至防御机制。尤为关键的是，本研究发现盐胁迫可有效促进胀果甘草中生物活性成分的积累。转录组分析显示，不同种质在盐胁迫后的基因表达模式存在显著差异，涉及植物激素信号转导、黄酮类生物合成及苯丙烷代谢等关键通路。
讨论：本研究为培育适应荒漠盐碱环境的优质胀果甘草种质提供了理论基础，同时为解析其高价值生物活性成分的合成与积累调控分子机制提供了重要参考。