Transcriptome analysis reveals the mechanism for blue-light-induced biosynthesis of delphinidin derivatives in harvested purple pepper fruit

Jinhui Gao; Yuwei Dou; Xiaotong Wang; Dalong Zhang; Min Wei; Yan Li

doi:10.3389/fpls.2023.1289120

Transcriptome analysis reveals the mechanism for blue-light-induced biosynthesis of delphinidin derivatives in harvested purple pepper fruit

Front Plant Sci. 2023 Oct 26:14:1289120. doi: 10.3389/fpls.2023.1289120. eCollection 2023.

Authors

Jinhui Gao¹, Yuwei Dou¹, Xiaotong Wang¹, Dalong Zhang^{1

2}, Min Wei^{1

2}, Yan Li^{1

2}

Affiliations

¹ College of Horticultural Science and Engineering, Shandong Agricultural University, Tai'an, Shandong, China.
² Scientific Observing and Experimental Station of Environment Controlled Agricultural Engineering in Huang-Huai-Hai Region, Ministry of Agriculture, Tai'an, Shandong, China.

Abstract

Anthocyanins are the main pigments that affect the color and quality of purple-fruited sweet pepper (Capsicum annuum). Our previous study indicated that blue light can induce anthocyanin accumulation in purple pepper. In view of its underlying mechanism that is unclear, here, anthocyanin content was determined, and transcriptome analysis was performed on pepper fruits harvested from different light treatments. As a result, among the identified anthocyanin metabolites, the levels of delphinidin (Dp) glycosides, including Dp-3-O-rhamnoside, Dp-3-O-rutinoside, and Dp-3-O-glucoside, were highly accumulated in blue-light-treated fruit, which are mainly responsible for the appearance color of purple pepper. Correlation between anthocyanin content and transcriptomic analysis indicated a total of 1,619 upregulated genes were found, of which six structural and 12 transcription factor (TF) genes were involved in the anthocyanin biosynthetic pathway. Structural gene, for instance, CaUFGT as well as TFs such as CaMYC2-like and CaERF113, which were highly expressed under blue light and presented similar expression patterns consistent with Dp glycoside accumulation, may be candidate genes for anthocyanin synthesis in response to blue-light signal.

Keywords: blue light; delphinidin derivatives; light spectrum; purple pepper; transcriptomic.

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This work was supported by the Natural Science Foundation of Shandong Province (ZR2020MC148), National Natural Science Foundation of China (32272796), and China Agriculture Research System (CARS-23-C04).