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...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.展开更多
Tung tree(Vernicia fordii)is an economically important woody oil plant that produces tung oil rich in eleostearic acid.Here,we report a high-quality chromosome-scale genome sequence of tung tree.The genome sequence wa...Tung tree(Vernicia fordii)is an economically important woody oil plant that produces tung oil rich in eleostearic acid.Here,we report a high-quality chromosome-scale genome sequence of tung tree.The genome sequence was assembled by combining Illumina short reads,Pacific Biosciences single-molecule real-time long reads,and Hi-C sequencing data.The size of tung tree genome is 1.12 Gb,with 28,422 predicted genes and over 73%repeat sequences.The V.fordii underwent an ancient genome triplication event shared by core eudicots but no further wholegenome duplication in the subsequent ca.34.55 million years of evolutionary history of the tung tree lineage.Insertion time analysis revealed that repeat-driven genome expansion might have arisen as a result of long-standing long terminal repeat retrotransposon bursts and lack of efficient DNA deletion mechanisms.The genome harbors 88 resistance genes encoding nucleotide-binding sites;17 of these genes may be involved in early-infection stage of Fusarium wilt resistance.Further,651 oil-related genes were identified,88 of which are predicted to be directly involved in tung oil biosynthesis.Relatively few phosphoenolpyruvate carboxykinase genes,and synergistic effects between transcription factors and oil biosynthesis-related genes might contribute to the high oil content of tung seed.The tung tree genome constitutes a valuable resource for understanding genome evolution,as well as for molecular breeding and genetic improvements for oil production.展开更多
基金This work was supported by the project of Yunnan Innovation Team Project, the Hundreds Oversea Talents Program of Yunnan Province, the Top Talents Program of Yunnan Province （Grant 20080A009）, the Key Project of the Natural Science Foundation of Yunnan Province （201401 PC00397）, National Science Foundation of China （U0936603）, Key Project of Natural Science Foundation of Yunnan Province （2008CC016）, Frontier Grant of Kunming Institute of Botany, CAS （672705232515）, Top Talents Program of Yunnan Province （20080A009）, and Hundreds Talents Program of Chinese Academy of Sciences （CAS） （to L.G.）.
文摘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.
基金supported by the National Key R&D Program of China(Grant No.2017YFD0600703)the National Forestry Public Welfare Industry Research Project of China(Grant No.201204403)+2 种基金the Outstanding Youth Project of the Education Department of Hunan Province,China(Grant No.17B279)the US Department of AgricultureAgricultural Research Service(USDA-ARS)National Program for Quality and Utilization of Agricultural Products(NP 306Grant No.CRIS 6054-41000-103-00-D).
文摘Tung tree(Vernicia fordii)is an economically important woody oil plant that produces tung oil rich in eleostearic acid.Here,we report a high-quality chromosome-scale genome sequence of tung tree.The genome sequence was assembled by combining Illumina short reads,Pacific Biosciences single-molecule real-time long reads,and Hi-C sequencing data.The size of tung tree genome is 1.12 Gb,with 28,422 predicted genes and over 73%repeat sequences.The V.fordii underwent an ancient genome triplication event shared by core eudicots but no further wholegenome duplication in the subsequent ca.34.55 million years of evolutionary history of the tung tree lineage.Insertion time analysis revealed that repeat-driven genome expansion might have arisen as a result of long-standing long terminal repeat retrotransposon bursts and lack of efficient DNA deletion mechanisms.The genome harbors 88 resistance genes encoding nucleotide-binding sites;17 of these genes may be involved in early-infection stage of Fusarium wilt resistance.Further,651 oil-related genes were identified,88 of which are predicted to be directly involved in tung oil biosynthesis.Relatively few phosphoenolpyruvate carboxykinase genes,and synergistic effects between transcription factors and oil biosynthesis-related genes might contribute to the high oil content of tung seed.The tung tree genome constitutes a valuable resource for understanding genome evolution,as well as for molecular breeding and genetic improvements for oil production.
