Full‐length transcriptome sequencing and transgenic tobacco revealed the key genes in the chlorogenic acid synthesis pathway of Sambucus chinensis L.

Abstract

Chlorogenic acid is a key chemical in antioxidation and antisepsis. Sambucus chinensis L. is an herbaceous plant rich in chlorogenic acid and a potential genetic resource for breeding high‐chlorogenic acid plants. However, there are few studies on the synthesis pathway of chlorogenic acid in S. chinensis. Our study found chlorogenic acid accumulation in S. chinensis to be organ‐specific, higher in leaves and buds but lower in roots, stems and fruits. A total number of 546,844 CCS (circular consensus sequence), including 402,767 full‐length nonchimeric (FLNC) and 39 annotated sequences related to the synthesis of chlorogenic acid, was obtained by single‐molecule real‐time sequencing technology (SMRT). qRT‐PCR showed that a number of key genes involved in chlorogenic acid synthesis were differentially expressed in various tissues of S. chinensis. Transgenic tobacco revealed that ectopic expression of the HCT homologous gene HCT‐45178 increased the content of chlorogenic acid. Our results should be the first report of full‐length transcriptome data of S. chinensis, which help to understand the basis of chlorogenic acid synthesis and provide a novel strategy for breeding tobacco cultivars with higher levels of chlorogenic acid.