Mitigation of -induced Coral Bleaching Through Bacterial Dysbiosis Prevention by

species are prevalent in ocean ecosystems, particularly , and pose a threat to corals and other marine organisms under global warming conditions. While microbiota manipulation is considered for coral disease management, understanding the role of commensal bacteria in stress resilience remains limited. Here, a single bacterial species () rather than a consortium of native was used to combat pathogenic and protect corals from bleaching. showed therapeutic activity , preventing a significant reduction in bacterial diversity in bleached corals. Notably, the structure of the bacterial community differed significantly among all the groups. In addition, compared with the bleached corals caused by , the network analysis revealed that complex interactions and positive correlations in the bacterial community of the protected non-bleached corals, indicating 's role in fostering synergistic associations. Many genera of bacteria significantly increased in abundance during infection, including , , , and , contributing to the pathogenicity of the bacterial community. However, effectively countered the proliferation of these genera, promoting potential probiotic and other taxa, while reducing the abundance of betaine lipids and the type VI section system of the bacterial community. These changes ultimately influenced the interactive relationships among symbionts and demonstrated that probiotic intervention can modulate coral-associated bacterial community, alleviate pathogenic-induced dysbiosis, and preserve coral health. These findings elucidated the relationship between the behavior of the coral-associated bacterial community and the occurrence of pathological coral bleaching.IMPORTANCEChanges in the global climate and marine environment can influence coral host and pathogen repartition which refers to an increased likelihood of pathogen infection in hosts. The risk of -induced coral disease is significantly heightened, primarily due to its thermos-dependent expression of virulent and populations. This study investigates how coral-associated bacterial communities respond to bleaching induced by . Our findings demonstrate that exhibits clear evidence of defense against pathogenic bacterial infection, contributing to the maintenance of host health and symbiont homeostasis. This observation suggests that bacterial pathogens could cause dysbiosis in coral holobionts. Probiotic bacteria display an essential capability in restructuring and manipulating coral-associated bacterial communities. This restructuring effectively reduces bacterial community virulence and enhances the pathogenic resistance of holobionts. The study provides valuable insights into the correlation between the health status of corals and how coral-associated bacterial communities may respond to both pathogens and probiotics.