Researchers may have figured out how to enhance the calming effects of tea by manipulating the microbes living in the plant's roots. A new study in Current Biology reveals that introducing specific bacteria into the tea plant's root increases the production of theanine, an amino acid related to calming effects and umami taste.
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| Fig. Theanine, Attribution: Minzfish, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons |
Zhenbiao Yang is a plant cell biologist at the Shenzhen Institute of Advanced Technology in China. He says theanine seems relaxing, and at least some studies show that it helps with sleep quality. The researchers focused on roots harvested from two types of oolong tea: Maoxie, which is sweet and low-theanine, and high-theanine Rougui, with a cinnamon-like flavor. They found that rougui roots harbored higher amounts of nitrogen-metabolizing microbes, which the tea plants required to produce theanine.
To this end, 21 bacterial strains were isolated from rougui roots, and an experimental microbial blend was synthesized, termed SynCom. They disinfected the tea seedlings' roots and planted them in sterilized vermiculite soil, which they later inoculated with dead or live SynCom and a nutrient solution with varying amounts of nitrogen.
From the age of 20 days onwards, all tea varieties tested were observed to have significantly increased theanine levels in the presence of live SynCom. The effect was most substantial in low nitrogen, and moxie leaves treated with live SynCom showed a significantly high amount of theanine contents compared to those treated with dead SynCom.
He proposes that the next steps would be the simplification of SynCom to one or two bacterial strains, making it more manageable for production and distribution. "This innovative approach might result in better quality tea and a more consistent, soothing experience for tea drinkers—likely revolutionizing how tea is grown and consumed worldwide."