Reciprocal transplant experiment reveals multiple factors influencing changes in coral microbial communities across climate zones

• Published in: The Science of the total environment 2024-01, Vol.907, p.167929-167929, Article 167929
• Main Authors: Chan, Ya-Fan, Chen, Yu-Hsiang, Yu, Sheng-Ping, Chen, Hsing-Ju, Nozawa, Yoko, Tang, Sen-Lin
• Format: Article
• Language: English
• Subjects: bacterial communities; Bacterial community structure; climate; Climate zones; community structure; Coral-associated bacteria; corals; environment; host preferences; microbiome; phylotype; Reciprocal transplant experiments; species
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2023.167929

Previous studies have demonstrated the influence of external factors (environmental factors and the coral host factors) on the community structure of coral-associated bacteria. However, the internal factors, e.g. the interaction within the bacterial community or bacteria itself, have often been overlooked in studies of the coral microbiome. Hence, we performed a reciprocal transplant of corals between two different climate zones to examine the resultant alterations in coral-associated bacterial communities. The findings highlight the significance of environmental factors, host selection, and highly resilient bacteria in shaping the coral microbial composition. The results support that coral species consistently harbor specific predominant bacterial groups influenced by host selection, while locations display unique bacterial taxa due to environmental variations. The transplantation of corals into new environments leads to a gradual shift in the bacterial community, from initially resembling that of the native location to eventually resembling that of the transplanted location, emphasizing the crucial role of bacterial community composition for coral survival under changing ambient conditions. Furthermore, highly resilient bacteria that persisted throughout the reciprocal transplant experiment demonstrated their adaptability to environmental and host changes, suggesting the presence of robust adaptation or resistance mechanisms in bacterial communities. Genetic adaptations within the prevalent bacterial group, Endozoicomonas, were also observed, suggesting variations in resilience and adaptation capabilities among different phylotypes. This study highlights the need to conduct further investigations into the coral-associated bacteria themselves, as they may hold some key insights into understanding the dynamics of coral-associated microbial communities. These data also highlight some key species of coral-associated bacteria which could benefit coral in response to alterations in ambient environment. [Display omitted] •Coral-associated bacterial community structure was shaped by both external and internal factors.•The transplant of corals into new environments led to a gradual shift in the bacterial community, resembling that of the new location.•Several ASVs of Endozoicomonas were dominant in the transplanted coral samples before and after experiment.•Highly resilient bacteria demonstrated their adaptability to environmental and host changes.