Multiomics analysis reveals the biosynthetic mechanism of isoquinoline alkaloids in Zanthoxylum armatum DC. Fruit

Zanthoxylum armatum DC. is a plant of the Brassicaceae family with high economic and medicinal value. Its fruit is a traditional spicy condiment and medicinal herb, and the prickly ash industry has developed into a pillar industry for specialty agricultural products in many regions of China. As one of the main components in the fruit of Z. armatum, isoquinoline alkaloids have good biological activity and play an important role in the formation of flavor quality, but fewer studies have been conducted on the mechanism of the biosynthetic pathway of isoquinoline alkaloids in Z. armatum. In this study, relevant metabolites and genes for isoquinoline alkaloid biosynthesis during three developmental periods of Z. armatum fruits were investigated to elucidate the mechanism of isoquinoline alkaloid biosynthesis. A total of 1,167 metabolites and 5,204 differentially expressed genes were detected by combining metabolome, SMRT sequencing and Illumina sequencing. The annotation results of KEGG database showed that four metabolites (levodopa, dopamine, tyramine, and magnoflorine) and eight differentially expressed genes were involved in the biosynthesis of isoquinoline alkaloids in Z. armatum fruits. Specially, metabolites Dopamine and Tyramine decreased with the development of Z. armatum, and the expression of the genes related to their regulation, Zardc00988 and Zardc23209, showed the same trend. This study contributes to our understanding of the mechanism of biosynthesis of Z. armatum isoquinoline alkaloids and provides a reference for the development of the medicinal value of Z. armatum.