Sweet potato tips are a potential vegetable with special flavor and high nutrients, but only the leafy type is popular among consumers, while most types of sweet potato tips are not widely accepted as a vegetable due to their bitter and astringent taste. Here, to reveal the biological pathway involved in the formation of bitter and astringent compounds in sweet potato tips, metabolomics and transcriptomics were performed for three sweet potato varieties with different levels of bitterness and astringency. Metabolomics analysis revealed that 139 metabolites might be related to both bitterness and astringency of sweet potato tips, and 31 flavonoid glycosides and hydroxycinnamic acid derivatives may synergistically affect bitterness and astringency. Histidine, alkaloids, and terpenoids specifically determine bitterness, while flavonol/flavone glycosides and seven phenolic acid derivatives specifically affect astringency. Transcriptome analysis identified 46 structural genes and 24 transcription factors responsible for the accumulation of bitter and astringent compounds, which were then used to construct the biosynthetic pathways. Two bHLHs were identified as hub genes in biosynthetic pathways of bitterness, and four MYBs and one bHLH were common transcription factors in the biosynthetic pathways of both bitterness and astringency. This study provides valuable insights into the formation mechanisms of bitter and astringent taste in sweet potato tips and important information for improvement of leafy type sweet potato.

中文翻译：

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代谢组学和转录组学揭示了与甘薯尖的苦味和涩味相关的代谢物和基因


红薯尖是一种具有特殊风味和高营养成分的潜在蔬菜，但只有叶类受到消费者的欢迎，而大多数类型的红薯尖由于其苦涩的味道而未被广泛接受为蔬菜。在这里，为了揭示甘薯尖中苦味和涩味化合物形成的生物学途径，对三种具有不同苦味和涩味的甘薯品种进行了代谢组学和转录组学。代谢组学分析显示，139 种代谢产物可能与甘薯尖的苦味和涩味有关，31 种类黄酮苷和羟基肉桂酸衍生物可能协同影响苦味和涩味。组氨酸、生物碱和萜类化合物特异性地决定苦味，而黄酮醇/黄酮糖苷和七种酚酸衍生物专门影响涩味。转录组分析确定了 46 个结构基因和 24 个转录因子，这些基因负责苦涩化合物的积累，然后用于构建生物合成途径。2 个 bHLHs 被鉴定为苦味生物合成途径中的枢纽基因，4 个 MYBs 和 1 个 bHLH 是苦味和涩味生物合成途径中的共同转录因子。本研究为甘薯小贴士苦味和涩味的形成机制提供了有价值的见解，并为改良叶型甘薯提供了重要信息。