Symbiont biosynthetic output tracks host developmental stage in a marine sponge holobiont
- 1University of Queensland
Abstract
Microbes have likely influenced animal development since its origin, yet how host and microbe partner across ontogeny remains poorly understood. Here we characterise a developmentally dynamic symbiosis in the marine sponge Amphimedon queenslandica by simultaneously profiling host and symbiont gene expression through embryonic, larval and metamorphic development. The transcriptional states of all three core, vertically inherited symbionts were strikingly stage-specific. Metabolic gene expression of the dominant symbiont, AqS1, peaked in brooded embryos, when host glycolytic and oxidative pentose phosphate pathway expression was lowest, and this peak was enriched for enzyme-encoding genes. In non-feeding larvae, AqS1 biosynthetic gene expression contracted across central carbon, vitamin and amino acid metabolism, while its import capacity increased. This contraction was selective. AqS1 genes for the final steps of arginine synthesis, which the host lacks, were minimally expressed in pre-competent larvae and upregulated at settlement together with host nitric oxide synthase, consistent with the known requirement for symbiont-derived arginine in nitric oxide-induced settlement. Histidine biosynthesis genes were instead maintained in the larva, coinciding with upregulation of host histidine-to-glutamate conversion. Host and symbiont nutrient transporters peaked in the same developmental stages more often than expected by chance. In the filter-feeding juvenile, host metabolism and efflux transport reached their maximum while the symbiont transcriptome changed little. These findings show that symbiont biosynthetic output tracks host developmental stage, and suggest that an inherited microbiome may contribute to successive stages of an animal life cycle through changes in its transcriptional activity rather than its composition.
Related
- Anterior hippocampal integration tracks the developmental emergence of flexible navigation through changing environments
- Functional division between root endosphere and rhizosphere microbiomes supports seagrass holobiont resilience under high nutrient and sulfide exposure
- Rapid coral bleaching recovery via symbiont transfer from healthy corals
- Inter‑symbiont horizontal gene transfer and functional partitioning in globally sampled lichen metagenomes
- Within-host evolution and transmission of a human gut symbiont across ecological scales
BibTeX
@misc{degnan2026symbiont,
title = {{Symbiont biosynthetic output tracks host developmental stage in a marine sponge holobiont}},
author = {S. M. Degnan and E. A. Maunders and Z. S. Wong and R. Fieth and B. M. Degnan and X. Xiang},
howpublished = {bioRxiv},
year = {2026},
month = sep,
doi = {10.64898/2026.09.29.755549},
url = {https://www.biorxiv.org/content/10.64898/2026.09.29.755549v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - Symbiont biosynthetic output tracks host developmental stage in a marine sponge holobiont
AU - S. M. Degnan
AU - E. A. Maunders
AU - Z. S. Wong
AU - R. Fieth
AU - B. M. Degnan
AU - X. Xiang
PY - 2026
DA - 2026/09/29
PB - bioRxiv
DO - 10.64898/2026.09.29.755549
UR - https://www.biorxiv.org/content/10.64898/2026.09.29.755549v1
AB - Microbes have likely influenced animal development since its origin, yet how host and microbe partner across ontogeny remains poorly understood. Here we characterise a developmentally dynamic symbiosis in the marine sponge Amphimedon queenslandica by simultaneously profiling host and symbiont gene expression through embryonic, larval and metamorphic development. The transcriptional states of all three core, vertically inherited symbionts were strikingly stage-specific. Metabolic gene expression of the dominant symbiont, AqS1, peaked in brooded embryos, when host glycolytic and oxidative pentose phosphate pathway expression was lowest, and this peak was enriched for enzyme-encoding genes. In non-feeding larvae, AqS1 biosynthetic gene expression contracted across central carbon, vitamin and amino acid metabolism, while its import capacity increased. This contraction was selective. AqS1 genes for the final steps of arginine synthesis, which the host lacks, were minimally expressed in pre-competent larvae and upregulated at settlement together with host nitric oxide synthase, consistent with the known requirement for symbiont-derived arginine in nitric oxide-induced settlement. Histidine biosynthesis genes were instead maintained in the larva, coinciding with upregulation of host histidine-to-glutamate conversion. Host and symbiont nutrient transporters peaked in the same developmental stages more often than expected by chance. In the filter-feeding juvenile, host metabolism and efflux transport reached their maximum while the symbiont transcriptome changed little. These findings show that symbiont biosynthetic output tracks host developmental stage, and suggest that an inherited microbiome may contribute to successive stages of an animal life cycle through changes in its transcriptional activity rather than its composition.
ER -