Scent of tea: metabonomic and ionomic basis of regional aroma of Wuyi rock tea

Rock tea produced in different regions has its unique aroma, commonly known as “regional aroma”, lacking scientific evidence and influencing factors. In this study, 350 tea plantations were randomly selected from four rock tea-producing regions in Wuyi Mountain, and 3,500 tea samples and 900 soil samples were collected, respectively. The aroma metabolites in tea leaves were determined by GC-TOF-MS, and 329 metabolic signals were analyzed by cluster analysis. From the results, the aroma metabolites could be divided into two branches according to producing regions: the samples from Gaoshan and Zhengyan regions, and others from the Banyan and Zhou tea regions, demonstrating the existence of the “regional aroma”. The concentration of 13 elements in tea leaves was determined by ICP-MS. Based on redundancy and correlation analyses, phosphorus (P) was the key element affecting the “regional aroma” of rock tea. The soil available P content and leaf P concentration of the Gaoshan samples rich in “regional aroma” were significantly lower than those from Zhou tea. Three key metabolites affected by P were screened by linear regression analysis. Field experiments showed that the relative contents of these three key aroma metabolites were significantly reduced by high P supply. Thus, this study revealed the regional differences in the aroma of rock tea and discovered that P was a key element that affected the “regional aroma”. The results could provide a scientific basis for improving the aroma quality of rock tea through nutrient management.