Transcriptome and metabolome analyses reveal chlorogenic acid accumulation in pigmented potatoes at different altitudes

Pigmented potato tubers are abundant in chlorogenic acids (CGAs), a metabolite with pharmacological activity. This article comprehensively analyzed the transcriptome and metabolome of pigmented potato Huaxingyangyu and Jianchuanhong at four altitudes of 1800 m, 2300 m, 2800 m, and 3300 m. A total of 20 CGAs and intermediate CGA compounds were identified, including 3-o-caffeoylquinic acid, 4-o-caffeoylquinic acid, and 5-o-caffeoylquinic acid. CGA contents in Huaxinyangyu and Jianchuanhong reached its maximum at an altitude of 2800 m and slightly decreased at 3300 m. 48 candidate genes related to the biosynthesis pathway of CGAs were screened through transcriptome analysis. Weighted gene co-expression network analysis (WGCNA) identified that the structural genes of phenylalanine deaminase (PAL), coumarate-3 hydroxylase (C3H), cinnamic acid 4-hydroxylase (C4H) and the transcription factors of MYB and bHLH co-regulate CGA biosynthesis. The results of this study provide valuable information to reveal the changes in CGA components in pigmented potato at different altitudes.