The External Microbiome Communicates with the Developing Zebrafish ( Danio rerio ) Embryo Through the Chorion and Influences Developmental Trajectory

The microbiome has a significant influence on host physiological processes including energy metabolism and neurobiology. However, current knowledge is largely limited to post-embryonic development, highlighting a notable gap in host-microbe communication during embryonic development, particularly in oviparous organisms. This is because the developing embryo is protected from the external environment by the chorion and typically considered to be sterile. We hypothesized the external microbiome influences embryonic development in oviparous organisms despite lack of physical contact with microbes, shaping host physiology beyond embryogenesis. To test this interaction, we utilized zebrafish ( ) reared germ-free or conventionalized with microbes at different times during embryonic development (6 and 24 hours post fertilization) to examine changes in transcriptomics, proteomics, and physiology at 32 hours post-fertilization. In contrast to the prevailing notion, we reveal a significant role of the external aquatic microbial community in regulating embryonic transcript and protein abundance associated with critical developmental processes including energy metabolism and neurodevelopment. Furthermore, we demonstrate the external microbial community drives differential expression of genes involved in cytochrome P450 directed xenobiotic metabolism and associated bioenergetic and behavioral responses following exposure to a CYP1A activator during embryogenesis. These findings reveal embryonic development is an integration of host genetic blueprints and external microbial cues, enhancing knowledge of fundamental developmental processes influenced by embryo-microbe interactions that shape developmental susceptibility to environmental stressors.

Duke Scholars

Author John F. Rawls Molecular Genetics and Microbiology

Author Nishad Jayasundara Environmental Natural Science