The quality of green tea is influenced by soil microbes in addition to soil conditions and the Camellia sinensis cultivar.
Arbuscular mycorrhizal (AM) fungi can significantly improve soil quality and crop productivity; however, the specific AM
fungal groups that affect the catechin quality index (CQI) of green tea are not yet clear. In the present study, rhizosphere
soil samples, root samples, and fresh tea leaves from six different Camellia sinensis cultivars in Hunan Province, China,
were collected. The taxonomic diversity and community composition of AM fungi in the rhizosphere soil and roots were
investigated using high-throughput Illumina amplicon sequencing technology, and the mycorrhizal colonization rate was
assessed. The two main AM fungal genera in the Camellia sinensis roots and rhizosphere were Paraglomus and Glomus.
A higher catechin quality index (HCQI) is correlated with greater accumulation of Paraglomus in the roots of Camellia
sinensis. The tea cultivar and the available phosphorus content in the rhizosphere soil significantly affected the mycorrhizal
colonization rate and the composition of the AM fungal community within the roots. The mycorrhizal colonization rate
affected the catechin composition, consequently influencing the CQI of green tea. Furthermore, fluctuations in the proportional
presence of Paraglomus and Glomus within the roots of Camellia sinensis notably affected the CQI. In summary,
increased mycorrhizal colonization and increased prevalence of Paraglomus substantially increase the CQI of green tea.
These findings have significant implications for the application of AM fungi in the production of high-quality green tea.