Functional determinism amid taxonomic stochasticity: insights into rules governing the assembly of algal-microbial symbioses

as a model, this study demonstrates that while the microbial species surrounding different algal strains vary greatly, their metabolic functions remain remarkably consistent. This finding reveals that algal hosts deterministically shape the functional needs of their microbiome, whereas the specific bacterial members fulfilling those roles are interchangeable. Such a "function-first" organization explains how algal-microbial symbioses persist despite environmental fluctuations. Understanding these assembly rules not only advances our knowledge of marine microbial ecology but also provides a conceptual foundation for engineering stable and resilient algal-microbial consortia for sustainable ocean biotechnologies.