4.3. Niche differentiation of Bathyarchaeia groups in paddy
soils
To the best of our knowledge, this represents the inaugural study
investigating the niche differentiation of Bathyarchaeia in
relation to the physicochemical characteristics of arable soils,
including pH and the C/N ratio. Our Random Forest analysis unveiled MAT
as the preeminent factor influencing the abundance ofBathyarchaeia in paddy soil (as depicted in Fig. 5a). The
relative abundance of Bathyarchaeia and Bathy-6 exhibits a
notably positive correlation with MAT (as seen in Fig. 4). This
observation harmonizes with our recent global meta-analysis (Xue et al.
2023), underscoring the influence of temperature on Bathyarchaeiasubgroups in soils, as similarly documented by previous study (Xiang et
al. 2017), who explored the impact of temperature onBathyarchaeia subgroups in soils via multivariate regression tree
analysis (Xiang et al. 2017). The discovery of Bathyarchaeia in
hot springs further accentuates its remarkable adaptability to
high-temperature environments (Barns et al. 1996).
We found the significance of the C/N ratio as an important factor in
regulating the relative abundance of Bathyarchaeia in paddy soils
(Fig. 4 and Fig. 5). However, in oligotrophic environments, such as sea
and mangrove sediments, TOC was reported to be the major limiting
factors for the abundance of Bathyarchaeia , regulating the
quantity of Bathyarchaeia (Pan et al. 2019; Yu et al. 2017).
However, in paddy soils, organic matter and ammonia are abundant due to
fertilization; therefore, the C/N ratio becomes the major factor
associated with the abundance of Bathyarchaeia . The dominant
subgroup differs in sediments and paddy soils, causing a niche
differentiation. These results can elaborate our understanding of the
niche preference of Bathyarchaeia in different environments and
give suggestions for the enrichment of Bathyarchaeia .
The results of Mantel analysis suggested that soil pH is also a key
factor regulating the Bathyarchaeia and Bathy-6 subgroups.
SEM results further supported the important role of soil pH in
influencing the community structure. The heatmap results also indicated
that the abundance and number of ASVs also significantly correlate with
soil pH. pH is a crucial factor in influencing bacterial, archaeal, and
fungal community structures in soils (Jiao et al. 2019; Tedersoo et al.
2020; Tripathi et al. 2018), also influencing the community structure ofBathyarchaeia in mangrove sediments (Pan et al. 2019).