Proteomic insights of interaction between ichthyotoxic dinoflagellate Karenia mikimotoi and algicidal bacteria Maribacter dokdonensis

Omics technology has been employed in recent research on algicidal bacteria, but previous transcriptomic studies mainly focused on bacteria or algae, neglecting their interaction. This study explores interactions between algicidal bacterium Maribacter dokdonesis P4 and target alga Karenia mikimotoi KMHK using proteomics. Proteomics responses of KMHK after co-culture with P4 in separate compartments of the transwell for 8 and 24 h were evaluated using tandem mass tags (TMT) proteomics, and changes of P4 proteomics were also assessed. Results indicated that essential metabolic processes of KMHK were disrupted after 8 h co-culture with P4. Disturbance of oxidative phosphorylation in mitochondria and electron transport chain in chloroplast raised oxidative stress, leading to endoplasmic reticulum stress and cytoskeleton collapse, and eventual death of KMHK cells. Iron complex outer-membrane receptor protein in P4 was upregulated after co-culture with KMHK for 24 h, suggesting P4 might secrete ferric siderophores, a potential algicidal substance.