Differential enrichment of key bacterial taxa in the rhizosphere of naturally growing and artificially restored Kandelia obovata forests

The structure of the soil bacterial community is crucial for maintaining ecosystem balance and facilitating material transformation in mangrove ecosystems. The large-scale destruction of mangroves directly impacts soil bacterial processes, potentially leading to ecosystem degradation. This study employed Illumina NovaSeq high-throughput sequencing to investigate the rhizosphere bacterial community of Kandelia obovata seedlings in both natural and artificially restored forests. Although alpha and beta diversity analyses revealed that the overall bacterial community structure was not significantly altered by artificial restoration, significant shifts in the abundance of specific bacterial genera were identified. A substantial proportion (86.1%-92.6%) of bacterial sequences remained unclassified at the genus level. Distinct dominant genera were observed across different groups: the well-grown artificial group (treat-k) was enriched with Sulfurovum, Actibacter, and Desulfatiglans (5.09%, 2.18%, and 1.82%, respectively), while the poorly-grown artificial group (treat-s) was characterized by Ignavibacterium, Prolixibacter, and Woeseia (2.10%, 1.21%, and 1.06%, respectively). The natural group was dominated by Woeseia, Desulfatiglans, and Halioglobus (1.56%, 1.53%, and 1.11%). Statistical analysis further confirmed that the abundance of several genera, including Ignavibacterium, Prolixibacter, and Haliangium differed significantly (p < 0.05) between the poorly-grown group (treat-s) and the better-grown groups (treat-k and natural). In conclusion, while artificial restoration did not restructure the rhizosphere bacterial community at a global level, it selectively shaped the microbial assemblage by enriching specific bacterial taxa, which might play a crucial role in determining the growth status of Kandelia obovata during restoration.