Metabolomic and Transcriptomic Analyses of the Flavonoid Biosynthetic Pathway for the Accumulation of Anthocyanins and Other Flavonoids in Sweetpotato Root Skin and Leaf Vein Base

Sweetpotato [Ipomoea
batatas (L.)
Lam.] is a major tuberous root crop that is rich in flavonoids. Here,
we discovered a spontaneous mutation in the color of the leaf vein
base (LVB) and root skin (RS) in the Zheshu 81 cultivar. The flavonoid
and anthocyanin metabolites and molecular mechanism were analyzed
using metabolome and transcriptome data. Compared to the wild type,
13 differentially accumulated metabolites (DAMs) in the LVB and 59
DAMs in the RS were all significantly downregulated. Moreover, all
the anthocyanin metabolites decreased significantly. The differentially
expressed genes (DEGs) encoding the key enzymes in the later enzymatic
reaction of anthocyanin and flavonoid were significantly downregulated
in the mutant. The expression trends of the transcription factor MYB
were evidently related to the anthocyanin content. These results offer
insights into the coloration in the LVB and RS and a theoretical basis
for determining the regulation of flavonoid and anthocyanin synthesis
in sweetpotato.

甘薯[Ipomoea batatas (L.) Lam.]是一类富含黄酮类物质的重要块根作物。本研究在浙薯81品种中发现了一处叶脉基部（leaf vein base, LVB）与薯皮（root skin, RS）色泽的自发突变。本研究借助代谢组与转录组数据，对其黄酮类、花青素类代谢物及分子机制展开分析。与野生型相比，叶脉基部的13种差异积累代谢物（differentially accumulated metabolites, DAMs）与薯皮的59种差异积累代谢物均显著下调。此外，所有花青素类代谢物的含量均显著降低。该突变体中，编码花青素与黄酮类物质合成后期关键酶的差异表达基因（differentially expressed genes, DEGs）均显著下调。转录因子MYB的表达趋势与花青素含量显著相关。本研究结果为阐明甘薯叶脉基部与薯皮的色泽形成机制提供了新视角，同时为调控甘薯黄酮类与花青素合成途径提供了理论依据。