Progress in the study of tea functional genomics

Tea plant is an important economic plant Due to the limitation of its own characteristics, the study of tea molecular biology, especially the functional genes, is relatively slow With the support of NSFC, Chen Liang, a researcher of Tea Research Institute of CAAS, took the lead in the research of functional genome and molecular marker of tea tree, and further understood the laws of tea tree growth and development, origin, domestication, breeding, resistance, etc There are nearly 60 tea producing countries in the world, but only a dozen of them produce more than 1500 kg / ha of tea annually Many old tea gardens with low productivity have low yield and poor quality In about 1.1 million hectares of tea plantations in China, less than 25% of tea plantations are planted with improved varieties, and most of the other tea plantations are planted with uneven group species, with their productivity declining, far below the world average The low yield and quality of tea production increase the production cost and reduce the economic benefits It is an important way to make a breakthrough in the development of tea production to obtain higher yield, better quality, stronger disease and insect resistance and stress resistance with better varieties Because tea is a perennial plant, one of the difficulties in the cultivation and promotion of new tea varieties is that the growth cycle is too long Therefore, in the breeding process, the work that rice breeding research can be completed in half a year may take several years on the tea tree At the same time, the seed setting rate of tea tree is low, and self pollination is not enough, and pure lines can not be obtained, which makes the commonly used hybrid breeding methods in other plants almost useless in tea tree With the development of plant genetic engineering technology, great achievements have been made in plant disease resistance, insect resistance, herbicide resistance and crop quality improvement, and a large number of genetically engineered plants (transgenic plants) have been obtained Some of these plants have been put into field experiments, some of them have been put into production gradually, which makes people's desire of directional transformation of crops come true "It is similar to human genome research in deciphering genetic information, understanding the origin of life, understanding human beings, mastering the laws of life, aging, death and disease diagnosis and treatment; gene research on tea is not only conducive to the selection of tea trees, improvement of stress resistance and other performance, but also deeper understanding of the growth and development of tea trees." "But tea trees are special, and previous studies have been relatively few," Chen said Starting from functional genes, cotton and other crops have been bred into high-quality and stress resistant varieties through biotechnology, and achieved good benefits However, the genetic engineering research on tea is still rare The main reason is that there is no practical breakthrough in the regeneration of tea plant cells after gene transfer, and the transgenic materials can not be restored to complete plants At the same time, people lack sufficient knowledge of the molecular genetics and molecular biology of tea "The quality, fragrance and unique functions of different teas are all derived from functional genes." "With the rapid development of modern biotechnology, the whole genome approach has developed to the third and fourth generations," Chen said Now people can get thousands of genes a day However, when we started to study the functional genes of tea trees, it was not easy to get one gene So many people around the world did tea research By 2001, only a dozen genes had been obtained At that time, we used EST (expressed sequence tag) method to obtain more than 1000 genes in half a year " In the 1990s, Chen Liang got his master's degree in agronomy from the Department of tea science of Zhejiang Agricultural University He came to the Tea Research Institute of the Chinese Academy of Agricultural Sciences and began to engage in the research of tea germplasm resources and molecular biology He successively went to the gene research center of Ehime University in Japan and the Department of molecular biology and genetics of Cornell University in the United States to engage in the research of plant molecular biology The main research directions are collection, conservation, identification and evaluation, innovative utilization and systematic classification of tea germplasm resources, molecular markers and functional genomics In 2001, with the support of NSFC, Chen Liang began to study genes related to tea aroma release process based on plant est His research team took the lead in the research of tea molecular markers in China The genetic stability of tea germplasm resources and the genetic diversity of tea plants and tea varieties were analyzed for the first time Three independent methods were proposed for molecular identification of tea germplasm resources And it took the lead in the research of tea functional genomics, established the first (second in the world) tea cDNA library in China, through high-throughput gene sequencing and bioinformatics comparison, isolation, cloning and annotation of tea functional genes The team cloned and sequenced the high-throughput cDNA of Longjing 43 shoots, and obtained the first 1684 tea expression sequence tags Through comparison, the researchers preliminarily identified the gene expression profile characteristics and expression abundance of tea shoots, and obtained partial or full-length sequences of more than 300 tea functional genes, including two genes closely related to tea aroma formation - β - glucosidase and β - primrose glycosidase genes They used new technology to build the first broad-spectrum tea tree gene chip based on the EST obtained, and initially built a research platform for tea tree resources and breeding based on the gene chip It is of theoretical and practical significance to obtain a large number of functional gene expression information of tea plant to understand and regulate the growth, development, resistance and metabolism of tea plant at the genomic level Sequencing is just the beginning "The origin, domestication, breeding, structure, and resistance of tea can all be solved genetically Sequencing is only a technical means, through these technical means, we can understand tea tree more deeply Scientists have measured the genes of tens of thousands of animals and plants, and human genome research has been done for more than ten years But tea is different from other crops At present, the sequencing of tea functional genes has not been completed, and we are not clear about some of its mechanisms At present, there are no transgenic tea varieties Chen Liang said NSFC and other early projects laid a good foundation for Chen Liang's follow-up research He has successively presided over more than 30 projects, such as the "863" project, the National Natural Science Foundation project, the international standards of the International Union for the protection of new plant varieties (UPOV), the national standards and agricultural industry standards, the "Eighth Five Year Plan", "Ninth Five Year Plan" and "Tenth Five Year Plan", the "Eleventh Five Year Plan" National Science and technology support plan, the science and technology basic conditions platform project of the Ministry of science and technology, and the basic work project of the Ministry of science and technology Item As the chief scientist, he was responsible for the development of the first test guide developed by China for the International Union for the protection of new plant varieties He has participated in the meeting of the International Union for the protection of new plant varieties on behalf of the Chinese government for five times to discuss and formulate the text of the test guide for tea trees.