Ziziphus jujuba var. spinosa Raw sequence reads. Ziziphus jujuba var. spinosa

Chinese sour jujube (Ziziphus jujuba var. spinosa (Bunge) Hu ex H. F. Chow) is one of woody plant with the same origin of medicine and food. Flavonoid are mainly distributed in its fruits as active ingredient, but the composition and biosynthesis mechanism of flavonoid in different harvest times are still unclear. The accumulation of flavonoids in Chinese sour jujube from five development stages was investigated, using a combined metabolomics and transcriptomics approach in this study. And a total of 1539 differentially accumulated metabolites (DAMs) and 11592 differentially expressed genes (DEGs) were identified. The flavonoid, flavone, and flavonol biosynthtic pathways were significantly enriched in the Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis of differentially expressed genes (DEGs) and differentially accumulated metabolites (DAMs). Furthermore, a comprehensive regulatory network was built for flavonoid biosynthesis and it was discovered that there is one FLS gene, and one NAC transcription factors (TFs) with a high connection with flavonoid biosynthesis by weighted gene co-expression network analysis (WGCNA). This finding was further verified by real-time quantitative polymerase chain reaction (PCR) experiments. This study offered candidate genes involved in flavonoid biosynthesis, information of flavonoid composition and characteristics of flavonoids accumulation, and provided references for the metabolic engineering of flavonoid biosynthesis in Chinese sour jujube.

酸枣（Ziziphus jujuba var. spinosa (Bunge) Hu ex H. F. Chow）是药食同源木本植物之一。其果实中以黄酮类化合物为主要活性成分，但不同采收期下酸枣黄酮类化合物的组成与生物合成机制仍未明确。本研究采用代谢组学与转录组学联合分析策略，对酸枣5个发育阶段的黄酮类化合物积累模式进行了探究，最终共鉴定得到1539个差异积累代谢物（differentially accumulated metabolites, DAMs）与11592个差异表达基因（differentially expressed genes, DEGs）。在差异表达基因（DEGs）与差异积累代谢物（DAMs）的京都基因与基因组百科全书（Kyoto Encyclopedia of Genes and Genomes, KEGG）富集分析中，黄酮类化合物、黄酮与黄酮醇生物合成通路均显著富集。此外，本研究构建了黄酮类化合物生物合成的全面调控网络，并通过加权基因共表达网络分析（weighted gene co-expression network analysis, WGCNA）发现，1个FLS基因与1个NAC转录因子（transcription factors, TFs）与黄酮类化合物生物合成具有高度关联。该发现通过实时荧光定量聚合酶链式反应（real-time quantitative polymerase chain reaction, PCR）实验得到了进一步验证。本研究筛选得到参与黄酮类化合物生物合成的候选基因，明确了酸枣黄酮类化合物的组成与积累特征，可为酸枣黄酮类化合物生物合成的代谢工程研究提供参考依据。