Project description:Recent studies have unveiled the deep sea as a rich biosphere, populated by species descended from shallow-water ancestors post-mass extinctions. Research on genomic evolution and microbial symbiosis has shed light on how these species thrive in extreme deep-sea conditions. However, early adaptation stages, particularly the roles of conserved genes and symbiotic microbes, remain inadequately understood. This study examined transcriptomic and microbiome changes in shallow-water mussels Mytilus galloprovincialis exposed to deep-sea conditions at the Site-F cold seep in the South China Sea. Results reveal complex gene expression adjustments in stress response, immune defense, homeostasis, and energy metabolism pathways during adaptation. After 10 days of deep-sea exposure, shallow-water mussels and their microbial communities closely resembled those of native deep-sea mussels, demonstrating host and microbiome convergence in response to adaptive shifts. Notably, methanotrophic bacteria, key symbionts in native deep-sea mussels, emerged as a dominant group in the exposed mussels. Host genes involved in immune recognition and endocytosis correlated significantly with the abundance of these bacteria. Overall, our analyses provide insights into adaptive transcriptional regulation and microbiome dynamics of mussels in deep-sea environments, highlighting the roles of conserved genes and microbial community shifts in adapting to extreme environments.
Project description:Mussels (Mytilus galloprovincialis) were exposed during 7 and 28 days in seawater (control), seawater + acetone (solvent control, SC), and 10 micrograms per Litre of tris(1,3-dichloro-2-propyl) phosphate (TDCPP). TDCPP was added from a stock solution prepared in acetone, the volume added being 100 µL per 30 L aquaria. The same volume of acetone was added to SC aquaria. Mussel density was 20 mussels per each 30 L aquaria at the beginning of the experiment and varied between 15 ‒ 20 mussels/30 L aquaria during the 28 days exposure period. Exposure conditions were the following: T = 15.6 ± 0.7 ºC, S = 35.5 ± 0.5 ppt, pH = 7.9 ± 0.1, O2 = 7.9 ± 0.6 mg L-1 and 10:14h light:dark photoperiod. Water was renewed twice per week and mussels were fed before every water renewal with a mixture of phytoplankton representing 1% of mussel tissue dry weight.
Project description:Transcriptional profiling of the mantle tissue across the four stages of male gonads development (winter peak) in a natural population of the marine mussel Mytilus galloprovincialis sampled in the Bizerta Lagoon, Tunisia, across November 2007 -March 2008. Background: Seasonal environmental changes may affect the physiology of Mytilus galloprovincialis (Lam.), an intertidal filter-feeder bivalve occurring commonly in Mediterranean and Atlantic coastal areas. We investigated seasonal variations in relative transcript abundance of the digestive gland and the mantle (gonads) of males and females. To identify gene expression trends, we used a medium-density cDNA microarray (1.7 K probes) in dual-color competitive hybridization analyses. Results: Hierarchical clustering of digestive gland microarray data showed two main branches, distinguishing profiles associated with the “hot” months (May–August) from the other months. Genes involved in chitin metabolism, associated with mussel nutrition and digestion, showed higher expression during summer. Moreover, we found different gene expression patterns in the digestive glands of males and females during the four stages of mussel gonadal development. Microarray data from gonadal transcripts also displayed clear patterns during the different developmental phases with peak relative mRNA abundance at the ripe phase (stage III) for both sexes. Conclusion: These data showed a clear temporal pattern in gene expression profiles of mussels sampled over an annual cycle. Physiological response to thermal variation, food availability, and reproductive status across months may contribute to variation in gene expression.
Project description:Transcriptional profiling of the mantle tissue across the four stages of female gonads development (winter peak) in a natural population of the marine mussel Mytilus galloprovincialis sampled in the Bizerta Lagoon, Tunisia, across November 2007 -March 2008. Background: Seasonal environmental changes may affect the physiology of Mytilus galloprovincialis (Lam.), an intertidal filter-feeder bivalve occurring commonly in Mediterranean and Atlantic coastal areas. We investigated seasonal variations in relative transcript abundance of the digestive gland and the mantle (gonads) of males and females. To identify gene expression trends, we used a medium-density cDNA microarray (1.7 K probes) in dual-color competitive hybridization analyses. Results: Hierarchical clustering of digestive gland microarray data showed two main branches, distinguishing profiles associated with the “hot” months (May–August) from the other months. Genes involved in chitin metabolism, associated with mussel nutrition and digestion, showed higher expression during summer. Moreover, we found different gene expression patterns in the digestive glands of males and females during the four stages of mussel gonadal development. Microarray data from gonadal transcripts also displayed clear patterns during the different developmental phases with peak relative mRNA abundance at the ripe phase (stage III) for both sexes. Conclusion: These data showed a clear temporal pattern in gene expression profiles of mussels sampled over an annual cycle. Physiological response to thermal variation, food availability, and reproductive status across months may contribute to variation in gene expression.