The Tea Tree Genome Provides Insights into Tea Flavor and Independent Evolution of Caffeine Biosynthesis

• Published in: Molecular plant Vol. 10; no. 6; pp. 866 - 877
• Main Authors: Xia, En-Hua, Zhang, Hai-Bin, Sheng, Jun, Li, Kui, Zhang, Qun-Jie, Kim, Changhoon, Zhang, Yun, Liu, Yuan, Zhu, Ting, Li, Wei, Huang, Hui, Tong, Yan, Nan, Hong, Shi, Cong, Shi, Chao, Jiang, Jian-Jun, Mao, Shu-Yan, Jiao, Jun-Ying, Zhang, Dan, Zhao, Yuan, Zhao, You-Jie, Zhang, Li-Ping, Liu, Yun-Long, Liu, Ben-Ying, Yu, Yue, Shao, Sheng-Fu, Ni, De-Jiang, Eichler, Evan E., Gao, Li-Zhi
• Format: Journal Article
• Language: English
• Published: England Elsevier Inc 05.06.2017
• Subjects: Beverages; biosynthesis; caffeine; Caffeine - biosynthesis; Camellia sinensis; Camellia sinensis - chemistry; catechin; Comparative genomics; enzyme activation; evolution; flavor; genes; Genomics - methods; Global adaptation; metabolomics; Plant Leaves - genetics; Plant Leaves - metabolism; Plant Proteins - genetics; retrotransposons; stress tolerance; tea; Tea flavor; Tea tree genome; Tea-proccessing suitability; trees; Tea-proccessing suitability; Comparative genomics; Global adaptation; Caffeine biosynthesis; Tea tree genome; Tea flavor
• ISSN: 1674-2052; 1752-9867; 1752-9867
• DOI: 10.1016/j.molp.2017.04.002

Tea is the world＇s oldest and most popular caffeine-containing beverage with immense economic, medicinal, and cultural importance. Here, we present the first high-quality nucleotide sequence of the repeat-rich （80.9%）, 3.02-Gb genome of the cultivated tea tree Camellia sinensis. We show that an extraordinarily large genome size of tea tree is resulted from the slow, steady, and long-term amplification of a few LTR retrotransposon families. In addition to a recent whole-genome duplication event, lineage-specific expansions of genes associated with flavonoid metabolic biosynthesis were discovered, which enhance catechin production, terpene enzyme activation, and stress tolerance, important features for tea flavor and adaptation. We demonstrate an independent and rapid evolution of the tea caffeine synthesis pathway relative to cacao and coffee. A comparative study among 25 Camellia species revealed that higher expression levels of most flavonoid- and caffeinebut not theanine-related genes contribute to the increased production of catechins and caffeine and thus enhance tea-processing suitability and tea quality. These novel findings pave the way for further metabolomic and functional genomic refinement of characteristic biosynthesis pathways and will help develop a more diversified set of tea flavors that would eventually satisfy and attract more tea drinkers worldwide.