College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou, China.
Institute of Subtropical Fruits, Fujian Agriculture and Forestry University, Fuzhou, China.
J Food Biochem. 2021 Sep;45(9):e13878. doi: 10.1111/jfbc.13878. Epub 2021 Aug 2.
Fruit sweetness being an important factor of organoleptic quality directly affects the consumers' preferences for fresh fruit consumption, and is influenced by the composition and quantity of sugars. In this study, four soluble sugars (sucrose, fructose, glucose, and sorbitol) were identified and quantified in plum fruits cv. 'Huangguan' at four different maturity stages (fruitlet, green, veraison, and mature stage). The results revealed that sucrose and glucose are major soluble sugar components at the fruitlet and mature stages, respectively. RNA-Seq analysis was carried out and 6,778 differentially expressed genes (DEGs) were identified, including 121 genes involved in sugar metabolism. Furthermore, a total of 39 transcripts of 8 gene families encoding key enzymes related to the metabolism and accumulation of soluble sugars were separately identified. ERD6L (gene 103322904) was involved in keeping a balance of glucose between the inside and outside of vacuole. SS (gene 103333990) and SDH (gene 103335104) regulated the accumulation of fructose at the green stage. SDH (gene 103335104) controlled the degradation of sorbitol at the green stage. SS (gene 103333990) and PFK (gene 103333391) regulated the degradation of sucrose at the early stages of fruit development. Moreover, NINV (gene 103331108) regulated the accumulation of total sugar in plum. Genes 103321334 and 103335689 were important bZIP transcription factors that regulate the accumulation of glucose and fructose in fruits. Twelve DEGs were selected and validated to observe the relative accuracy of transcriptome sequencing data using qRT-PCR. Gene expression patterns were consistent between qRT-PCR and RNA-Seq data, indicating the reliability of RNA-Seq data. PRACTICAL APPLICATIONS: The results of this study provided new insights into comprehensive understanding of the genetic control of sugar metabolism and accumulation in plum fruits.
水果的甜度是感官品质的一个重要因素，直接影响消费者对新鲜水果的偏好，而甜度受糖的组成和含量的影响。本研究在四个不同成熟阶段（幼果期、绿熟期、转色期和完熟期）鉴定并定量了‘皇冠’李果实中的四种可溶性糖（蔗糖、果糖、葡萄糖和山梨醇）。结果表明，蔗糖和葡萄糖分别是幼果期和完熟期的主要可溶性糖成分。进行了 RNA-Seq 分析，鉴定出 6778 个差异表达基因（DEGs），包括 121 个参与糖代谢的基因。此外，分别鉴定出 8 个基因家族的 39 个转录本，这些基因家族编码与可溶性糖代谢和积累相关的关键酶。ERD6L（基因 103322904）参与维持液泡内外葡萄糖的平衡。SS（基因 103333990）和 SDH（基因 103335104）在绿熟期调控果糖的积累。SDH（基因 103335104）在绿熟期调控山梨醇的降解。SS（基因 103333990）和 PFK（基因 103333391）在果实发育早期调控蔗糖的降解。此外，NINV（基因 103331108）调控李果实中总糖的积累。基因 103321334 和 103335689 是调控果实中葡萄糖和果糖积累的重要 bZIP 转录因子。选择并验证了 12 个 DEG，用 qRT-PCR 观察转录组测序数据的相对准确性。qRT-PCR 和 RNA-Seq 数据的基因表达模式一致，表明 RNA-Seq 数据的可靠性。实际应用：本研究结果为全面了解李果实糖代谢和积累的遗传调控提供了新的见解。
