Xu Nianao, Yang Fan, Dai Weifeng, Yuan Cheng, Li Jinxue, Zhang Hanqi, Ren Youdi, Zhang Mi
Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming 650500, China.
Institute of Tropical and Subtropical Cash Crops, Yunnan Academy of Agricultural Sciences, Ruili 678600, China.
Plants (Basel). 2024 Oct 15;13(20):2888. doi: 10.3390/plants13202888.
Sodium humate (SH) is the sodium salt of humic acid. Our previous research has demonstrated that SH has the ability to enhance the levels of total flavonoids in various parts of lemons, including the leaves, peels, pulps, and seeds, thereby improving the quality of lemons. In the current study, the regulation effect of SH on the biosynthesis and content of lemon flavonoid compounds was examined using transcriptome sequencing technology and flavonoid metabolomic analysis. Following SH treatment, the transcriptome sequencing analysis revealed 320 differentially expressed genes (DEGs) between samples treated with SH and control (CK) samples, some of which were associated with the phenylalanine pathway by KEGG annotation analysis. The levels of seven flavonoid compounds identified in lemon peels were observed to increase, and eriocitrin and isoorientin were identified as differential metabolites (DMs, VIP > 1) using OPLS-DA analysis. The integrated analysis of transcriptomics and flavonoid metabolomics indicates that SH treatment induces alterations in gene expression and metabolite levels related to flavonoid synthesis. Specifically, SH influences flavonoid biosynthesis by modulating the activity of key enzymes in the phenylalanine pathway, including HCT (O-hydroxycinnamoyltransferase) and F5H (ferulate-5-hydroxylase).
腐植酸钠（SH）是腐植酸的钠盐。我们之前的研究表明，SH能够提高柠檬各个部位（包括叶片、果皮、果肉和种子）中总黄酮的含量，从而改善柠檬的品质。在本研究中，利用转录组测序技术和黄酮类代谢组学分析，研究了SH对柠檬黄酮类化合物生物合成和含量的调控作用。SH处理后，转录组测序分析显示，SH处理组与对照组（CK）样本之间有320个差异表达基因（DEGs），通过KEGG注释分析发现其中一些基因与苯丙氨酸途径相关。观察到柠檬果皮中鉴定出的七种黄酮类化合物的含量增加，通过OPLS-DA分析，异甘草素和异荭草素被鉴定为差异代谢物（DMs，VIP>1）。转录组学和黄酮类代谢组学的综合分析表明，SH处理会引起与黄酮类合成相关的基因表达和代谢物水平的变化。具体而言，SH通过调节苯丙氨酸途径中关键酶的活性来影响黄酮类生物合成，这些关键酶包括HCT（O-羟基肉桂酰转移酶）和F5H（阿魏酸-5-羟化酶）。
