4.1. Bathyarchaeia inhabiting paddy soil is highly abundant but
not diverse
Bathyarchaeia exhibits a widespread distribution in diverse
environments. Past investigations have predominantly concentrated on
marine, mangrove, and freshwater sediments, where Bathyarchaeiahave been notably abundant (Baker et al. 2020; Lazar et al. 2015; Pan et
al. 2019; Yu et al. 2017). Nevertheless, the presence ofBathyarchaeia in arable soils has received limited scrutiny.
Within this study, we have determined that the proportion ofBathyarchaeia relative to all archaea varies significantly among
distinct paddy soils, constituting an average of approximately 31.2%.
Concerning the community structure of Bathyarchaeia in paddy
soils, the Bathy-6 subgroup exclusively predominates across all
surveyed sites, accompanied by a smaller representation of ASVs
associated with Bathy-11 , Bathy-15 , Bathy-5bb , andBathy-17 . In comparison with our recent meta-analysis (Xue et al.
2023), the subgroup diversity of Bathyarchaeia in paddy soils
within eastern China (comprising 5 subgroups) appeared lower than the
global scale (comprising 7 subgroups), as Bathy-18 andBathy-5b were not detected in our study. This discrepancy might
be elucidated by the greater diversity observed in paddy soils
worldwide. Furthermore, previous studies have indicated thatBathyarchaeia exhibit a relatively low relative abundance in
certain paddy soils (Jiao et al. 2019), while Zheng et al. reported a
higher abundance of Bathyarchaeia in water-saturated paddy soils
compared to cultivar-rotation paddy soils and upland soils (Zheng et al.
2019). All these findings collectively suggest that the abundance and
diversity of Bathyarchaeia in paddy soils are considerably
influenced by pedoclimatic conditions. Therefore, it would be beneficial
to explore the specific soil conditions that favor either low or high
relative abundance of Bathyarchaeia in future research.