The aroma of tea is the distinctive fragrance naturally emitted by the tea leaves themselves. So, where does this tea aroma come from? Actually, just like the scent of flowers, it originates from the tea plant. The tea plant is an important economic crop, but research in tea tree molecular biology, particularly functional gene studies, has progressed relatively slowly due to the plant's inherent characteristics. Let's discuss how this tea aroma actually develops.

Currently, there are nearly 60 tea-producing countries worldwide, but only about a dozen have tea gardens with an annual yield exceeding 1,500 kilograms per hectare. In China, out of approximately 1.1 million hectares of tea gardens, less than 25% are planted with improved varieties. This is because tea plants are perennial, and one of the challenges in breeding and promoting new tea tree varieties is their long growth cycle.

The quality, aroma, and unique properties of different teas all stem from functional genes. Modern biotechnology is advancing rapidly, with whole-genome methods already evolving to the third and fourth generations. Today, thousands of genes can be obtained in a single day. However, when we began researching tea tree functional genes, obtaining even one gene was not easy. Despite numerous researchers worldwide studying tea, by 2001, only about a dozen genes had been acquired. At that time, we used the EST method and managed to obtain over a thousand genes within six months.

The aroma of tea can be high or low, long-lasting or short, light or strong, elegant or common, clear or dull, fresh or stale. The fragrance profiles are incredibly diverse. Green tea most commonly exhibits a chestnut-like aroma. For black tea, the most frequent descriptor is "rich aroma," often reminiscent of apples. Oolong tea displays a variety of fragrance types, with distinct varietal aromas such as Huangjingui fragrance, Qilan fragrance, and Maoxie fragrance. For Pu-erh tea, a pure aroma is considered good, a lotus scent is superior, and an aged woody fragrance is regarded as the highest quality.

For the first time, an analysis was conducted on the genetic stability of tea tree germplasm resources and the genetic diversity of tea section plants and tea tree varieties. Three independent methods were proposed for the molecular identification of tea tree germplasm resources. Furthermore, research on tea tree functional genomics was initiated, leading to the establishment of China's first tea tree cDNA library. Through high-throughput gene sequencing, bioinformatics comparison, separation, cloning, and annotation, functional genes of the tea tree were identified.

Through comparative analysis, researchers preliminarily clarified the gene expression profile characteristics and abundance in tea tree new shoots. They obtained partial or full-length sequences of over 300 tea tree functional genes, including two genes closely related to tea aroma formation: β-glucosidase and β-primeverosidase genes.

Aroma can accumulate in the body. Regularly drinking high-aroma teas may impart fragrance to the body. The aromatic components are absorbed, circulate through the bloodstream to every capillary, and over time, accumulate. This gradual buildup releases aromatic substances, allowing one to both appreciate the fragrance personally and share it with others.

We hope that more people will engage in tea research to further discover the benefits and effects of tea on human health. At the same time, we aim to deepen our understanding of tea aroma and other fundamental aspects of tea. Learning represents progress, and research marks the beginning of development.