You'd think the complex flavor in a quality cup of tea would depend mainly on the tea varieties used to make it. But a study appearing in the journal Current Biology on 15 February 2024 shows that the making of a delicious cup of tea depends on another key ingredient: the collection of microbes found on tea roots. By altering that assemblage, the authors showed that they could make good-quality tea even better.
"Significant disparities in microbial communities, particularly nitrogen metabolism-related microorganisms, were identified in the roots of tea plants with varying qualities through microbiomics," says Tongda Xu of Fujian Agriculture and Forestry University in Fujian, China. "Crucially, through the isolation and assembly of a synthetic microbial community from high-quality tea plant roots, we managed to notably enhance the amino acid content in various tea plant varieties, resulting in an improvement in tea quality."
China harbors a wealth of genetic resources for growing tea plants. But, the researchers explain, improving the quality of tea through molecular genetic breeding methods is challenging. There's interest in finding other ways to modify and enhance tea, perhaps including the use of microbial agents. Earlier studies showed that soil microbes living in plant roots affect the way nutrients are taken up and used within plants. In the new study, the researchers wanted to learn more about how specifically root microbes affect tea quality. They found that the microbes in tea roots affected their uptake of ammonia, which in turn influenced the production of theanine, which is key for determining a tea's taste. They also saw variations in the microbes colonizing different teas.
By comparing tea varieties with different amounts of theanine, they identified a set of microbes that looked promising for altering nitrogen metabolism and boosting theanine levels.
(Source: Agriculture and Food News, ScienceDaily.