Mechanism underlying the carotenoid accumulation in shaded tea leaves

Xiumin Fu; Jiaming Chen; Jianlong Li; Guangyi Dai; Jinchi Tang; Ziyin Yang

doi:10.1016/j.fochx.2022.100323

Mechanism underlying the carotenoid accumulation in shaded tea leaves

Food Chem X. 2022 May 4:14:100323. doi: 10.1016/j.fochx.2022.100323. eCollection 2022 Jun 30.

Authors

Xiumin Fu¹, Jiaming Chen^{1

2}, Jianlong Li³, Guangyi Dai¹, Jinchi Tang³, Ziyin Yang^{1

2

4}

Affiliations

¹ Guangdong Provincial Key Laboratory of Applied Botany & Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, South China Botanical Garden, Chinese Academy of Sciences, No. 723 Xingke Road, Tianhe District, Guangzhou 510650, China.
² University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing 100049, China.
³ Tea Research Institute, Guangdong Academy of Agricultural Sciences & Guangdong Provincial Key Laboratory of Tea Plant Resources Innovation and Utilization, No. 6 Dafeng Road, Tianhe District, Guangzhou 510640, China.
⁴ Center of Economic Botany, Core Botanical Gardens, Chinese Academy of Sciences, No. 723 Xingke Road, Tianhe District, Guangzhou 510650, China.

Abstract

Carotenoids contribute to tea leaf coloration and are the precursors of important aromatic compounds. Shading can promote the accumulation of carotenoids in tea leaves, but the underlying mechanism remains unknown. In the study, we analyzed the content and composition of carotenoids, and transcript levels and functions of related genes in carotenoid biosynthesis using HPLC, qRT-PCR, and heterologous expression system. It was found that long-term shading (14 days, 90% shading) significantly increased the total carotenoid content in tea leaves, and increased the expression of non-mevalonate pathway (MEP) genes (CsDXS1 and CsDXS3) and key genes in carotenoid synthesis pathway (CsPSY, CsLCYB, and CsLCYE). Long-term exposure to darkness (14 days, 0 lx) decreased the transcription of most carotenoid biosynthetic genes and adversely affected carotenoid accumulation. Furthermore, CsDXS1, CsDXS3, CsPSY, CsLCYB, and CsLCYE were functionally identified and contributed to the enhanced accumulation of carotenoids in tea leaves in response to long-term shading.

Keywords: Biosynthesis; Camellia sinensis; Carotenoids; Metabolic regulation; Shade; Tea; α-Carotene (PubChem CID: 4369188); β-Carotene (PubChem CID: 54603957); δ-Carotene (PubChem CID: 5281230).