Peanut (Arachis hypogaea L.) is an important source of oil and food around the world, and the testa color affects its appearance and commercial value. However, few studies focused on the mechanism of pigment formation in peanut testa. In this study, cultivars Shanhua 15 with pink testa and Zhonghua 12 with red testa were used as materials to perform the combined analysis of transcriptome and metabolome. A total of 198 flavonoid metabolites were detected, among which petunidin 3-O-glucoside and cyanidin O-acetylhexoside in Zhonghua12 were 15.23 and 14.72 times higher than those of Shanhua 15 at the R7 stage, revealing the anthocyanins underlying the red testa. Transcriptome analysis showed that there were 6059 and 3153 differentially expressed genes between Shanhua 15 and Zhonghua 12 in different growth periods, respectively. These differentially expressed genes were significantly enriched in the flavonoid biosynthesis, biosynthesis of secondary metabolites, and metabolic pathways. Integrated analysis of transcriptome and metabolome indicated CHS gene (arahy.CM90T6), F3H genes (arahy. 8F7PE4 and arahy. K8H9R8), and DFR genes (arahy. LDV9QN and arahy. X8EVF3) may be the key functional genes controlling the formation of pink and red testa in peanut. Transcription factors MYB (arahy.A2IWKV, arahy.US2SKM, arahy.SJGE27, arahy.H8DJRL, and arahy.PR7AYB), bHLH (arahy.26781N, arahy.HM1IVV, and arahy.MP3D3D), and WD40 (arahy.L6JJW9) in the biosynthetic pathway of anthocyanin were significantly upregulated in Zhonghua 12 which may be the key regulatory genes in testa pigment formation. This is a comprehensive analysis on flavonoid metabolites and related genes expression in peanut testa, providing reference for revealing the regulatory mechanism of pigment accumulation in peanut testa.

中文翻译：

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转录组和代谢组分析揭示花生粉红色和红色种皮中的花青素代谢（Arachis hypogaea L.）

花生 ( Arachis hypogaeaL.) 是世界范围内重要的石油和食品来源，种皮颜色影响其外观和商业价值。然而，很少有研究关注花生种皮色素形成的机制。本研究以粉种皮山花15和红色种皮中华12为材料进行转录组和代谢组的联合分析。共检测到198种黄酮代谢物，其中中华12号矮牵牛花素3-O-葡萄糖苷和花青素O-乙酰己糖苷在R7期分别比山花15高15.23倍和14.72倍，揭示了红种皮下的花青素。转录组分析表明，山花15和中华12不同生育期的差异表达基因分别为6059和3153个。这些差异表达的基因在类黄酮生物合成、次级代谢产物的生物合成和代谢途径中显着富集。转录组和代谢组的综合分析表明 CHS 基因（arahy.CM90T6 )、F3 H基因( arahy.8F7PE4和arahy.K8H9R8 )和D​​FR基因( arahy.LDV9QN和arahy.X8EVF3 )可能是控制花生粉红色和红色种皮形成的关键功能基因。转录因子的MYB（arahy.A2IWKV，arahy.US2SKM，arahy.SJGE27，arahy.H8DJRL，和arahy.PR7AYB）的bHLH（arahy.26781 N，arahy.HM1IVV，和arahy.MP3D3D），和WD40（arahy.L6JJW9)在花青素生物合成途径中在中华12号中显着上调，这可能是种皮色素形成的关键调控基因。对花生种皮中黄酮类代谢产物及相关基因表达的综合分析，为揭示花生种皮色素积累的调控机制提供参考。