Project description:Escaped domesticated individuals can introduce disadvantageous traits into wild populations due to both adaptive differences between population ancestors and human-induced changes during domestication. In contrast to their domesticated counterparts, some endangered wild Atlantic salmon populations encounter during their marine stage large amounts of suspended sediments, which may act as a selective agent. We used microarrays to elucidate quantitative transcriptional differences between a domesticated salmon strain, a wild population and their first-generation hybrids during their marine life stage, to describe transcriptional responses to natural suspended sediments, and to test for adaptive genetic variation in plasticity relating to a history of natural exposure or nonexposure to suspended sediments. We identified 67 genes differing in transcription level among salmon groups. Among these genes, processes related to energy metabolism and ion homoeostasis were over-represented, while genes contributing to immunity and actin-/myosin-related processes were also involved in strain differentiation. Domestic–wild hybrids exhibited intermediate transcription patterns relative to their parents for two-thirds of all genes that differed between their parents; however, genes deviating from additivity tended to have similar levels to those expressed by the wild parent. Sediments induced increases in transcription levels of eight genes, some of which are known to contribute to external or intracellular damage mitigation. Although genetic variation in plasticity did not differ significantly between groups after correcting for multiple comparisons, two genes (metallothionein and glutathione reductase) tended to be more plastic in response to suspended sediments in wild and hybrid salmon, and merit further examination as candidate genes under natural selection.
Project description:<p>Marine sponges can host abundant and diverse microbiomes, which can largely influence the metabolism and other phenotypic traits of the host. However, information on the potential relationships between sponge microbiomes and metabolic signatures, other than secondary metabolites explored for biotechnological purposes, needs further investigation. Applying an integrated approach, we investigated the microbiomes associated with 4 ubiquitous Mediterranean sponge species (i.e., Petrosia ficiformis, Chondrosia reniformis, Crambe crambe and Chondrilla nucula), correlated with their metabolomic patterns (in terms of lipidomics) and microbial predicted functions. Microscopy observations of sponge tissues revealed differences in microbial abundances, which, however, were only partially linked to their diversity assessed through metabarcoding. The microbiomes of the 4 sponges showed a species-specific composition and a different core size, which was independent from the microbial diversity of the surrounding seawater. Predicted functions of the associated microbiomes allowed identifying 2 functional host clusters: one more related to heterotrophic pathways and the other more linked to phototrophic activities. Differences in the microbiomes were also associated with different metabolic profiles, mostly due to specific compounds characterizing the host and its microbiome. Overall, this study provides new insights on the functionality of sponges and their prokaryotic symbioses’, and in particular, it discloses a descriptive sketch of the diverse compartments forming the sponge holobiont.</p>