Longjing tea tree chromosome-level genome assembly was successful

, Nature-Communication published an important breakthrough in the whole genome assembly of tea tree and the evolution of tea tree origin. The study was led by the Tea Research Institute of the Chinese Academy of Agricultural Sciences (hereinafter referred to as the Tea Institute) and the Shenzhen Agricultural Genomics Research Institute of the Chinese Academy of Agricultural Sciences (hereinafter referred to as the Genomics Institute) and was carried out in cooperation with the Kunming Institute of Zoology of the Chinese Academy of Sciences (hereinafter referred to as the Kunming Institute of Zoology) and the Tea Research Institute of the Yunnan Academy of Agricultural Sciences. The results provide rich material for tea tree genomics and breeding research, as well as tea tree genetic and evolutionary research.
tea tree originated in China and is popular all over the world, with more than two-thirds of the world's tea drink consumers. Tea tree is widely distributed in china, rich in species resources, six teas have their own characteristics, and the study of tea tree evolution is still few.Yang Yajun, author of
Communication, said that they first took Longjing 43, a well-known fine tea tree variety in China, as a material, and used their self-developed three-generation assembly software combined with high-volume chromosomal image capture (Hi-C) and other technologies to overcome the complex genome assembly problems with high genomic hybridization and high repeat sequence ratio, and completed the genome assembly at longjing 43 chromosome level.
Longjing 43 genome size of 3.26 Gb, DNA framework (scaffold) N50 reached 143.85 Mb, with good continuity, in the single base level and scaffold level have achieved high accuracy, obtained 33,556 high-quality annotated genes.
study found that Longjing 43 was expanding with disease resistance, flavor metabolism and self-indescing and related gene families, and positive selection of genes associated with resistance.
Based on assembled, high-quality genomes, the team resealed 139 representative tea tree materials from different countries and regions around the world, revealing systematic relationships between tea tree populations and depicting the evolutionary history of cultivated tea trees.
They found that the expansion of cultivated areas increased the hybridity and broad gene flow among tea tree populations, and that the wild close-edge population of tea trees was the ancestor of small and medium leaf tea varieties (most of which belong to tea variants in plant classification) and large leaf tea varieties (most of which belong to Assam tea variants in plant classification), and that there were differences in the direction of choice in the process of domestication. Small and medium leaf tea (tea variant) in the long-term domestication process associated with tea flavor terpene metabolic genes and disease-resistant genes are selected stronger than large leaf tea (Assam variant) tea tree.
Longjing 43 is an excellent variety from the West Lake Longjing group species, with its early germination, excellent quality, strong resistance and other fine economic conditions and welcomed by China's tea farmers, in China's main green tea production area in the forefront of the promotion area. This year coincides with the 60th anniversary of the discovery of Longjing 43, the results of which explain the molecular nature of Longjing 43's high quality and resistance to resistance, and have good commemorative significance.
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