Dominant role of abundant rather than rare bacterial taxa in maintaining agro-soil microbiomes under environmental disturbances

Elucidating the mechanisms underpinning the responses of abundant and rare microbial taxa to environmental disturbances is essential for understanding the biodiversity-stability relationship and maintaining microbial diversity. Here, we explored the response patterns of abundant and rare bacterial taxa to disturbances by invasive plant growth and oil contamination in agricultural soils across a large spatial scale (latitude gradient = 18.62°-46.51°). Our meta-analysis based on existing Illumina sequencing datasets showed that abundant taxa persisted under the disturbances whereas rare taxa were more easily affected, indicating the higher resilience or resistance of abundant taxa to disturbances. The responses of abundant taxa were associated with mean annual temperature at the sampling sites, while rare taxa instead showed stochastic responses. There were significantly negative linear regressions between bacterial α-diversity and community dissimilarities (disturbed vs. undisturbed soils), suggesting stronger resilience or resistance in those bacterial communities with higher α-diversity. This resilience or resistance was mainly associated with the α-diversity of abundant taxa. Our network analysis showed that the disturbances substantially decreased the strength of the connections, loosened the co-occurrence relationships, and reshaped the complex bacterial interactions. In the undisturbed soils, abundant taxa were located in central positions within the network more often than were rare taxa, while these trends were reversed in the disturbed soils. Our results suggest that abundant taxa play a dominant role in the stability and maintenance of agro-soil bacterial communities, while rare taxa could greatly influence local bacterial interactions under environmental disturbances.