A carregar...
Projeto de investigação
Freshwater Bivalves at the edge: Adaptation genomics under climate-change scenarios
Financiador
Autores
Publicações
The crown pearl V2: an improved genome assembly of the European freshwater pearl mussel Margaritifera margaritifera (Linnaeus, 1758)
Publication . Gomes-dos-Santos, André; Lopes-Lima, Manuel; Machado, André M.; Forest, Thomas; Achaz, Guillaume; Teixeira, Amílcar; Prié, Vincent; Castro, L. Filipe C.; Froufe, Elsa
Contiguous assemblies are fundamental to deciphering the composition of extant genomes. In
molluscs, this is considerably challenging owing to the large size of their genomes, heterozygosity,
and widespread repetitive content. Consequently, long-read sequencing technologies are
fundamental for high contiguity and quality. The first genome assembly of Margaritifera
margaritifera (Linnaeus, 1758) (Mollusca: Bivalvia: Unionida), a culturally relevant, widespread,
and highly threatened species of freshwater mussels, was recently generated. However, the
resulting genome is highly fragmented since the assembly relied on short-read approaches. Here,
an improved reference genome assembly was generated using a combination of PacBio CLR long
reads and Illumina paired-end short reads. This genome assembly is 2.4 Gb long, organized into
1,700 scaffolds with a contig N50 length of 3.4 Mbp. The ab initio gene prediction resulted in
48,314 protein-coding genes. Our new assembly is a substantial improvement and an essential
resource for studying this species’ unique biological and evolutionary features, helping promote
its conservation.
Population-specific phenotypic plasticity of endangered bivalves in response to extreme events
Publication . Gomes-dos-Santos, André; Lopes-Lima, Manuel; Silva, Beatriz; Machado, André M.; Pinto, Rui; Österling, Martin; Wallerius, Magnus Lovén; Urbańska, Maria; Golski, Janusz; Runowski, Sławomir; Kaźmierczak, Sandra; Teixeira, Amilcar; Sousa, Ronaldo; Castro, L. Filipe C.; Castro, Paulo; Carvalho, Francisco; Fonseca, Elza; Froufe, Elsa
Freshwater mussels are among the most endangered animal groups, highly sensitive to climate change due to their strict dependence on freshwater habitats. While freshwater mussels are often considered ecologically strict, their distribution across broad environmental gradients raises the possibility of population-specific adaptations mediated by phenotypic plasticity.
This study investigates whether geographically and climatically distinct populations of two freshwater mussel species (Unio pictorum and Unio delphinus) exhibit different transcriptomic responses to prolonged heat stress and whether these responses reveal signs of local adaptation.
We exposed northern and southern populations of both species to gradually increasing temperatures in controlled laboratory conditions, simulating a prolonged thermal extreme event, and RNA-seq was used to quantify differential gene expression.
Results showed strong differences between northern and southern populations of the two species, both in the magnitude and functional composition of transcriptomic responses. Southern populations exhibited intense expression shifts involving classical stress pathways, heat shock proteins, detoxification (cytochrome P450s), apoptosis, and energy metabolism, while northern populations, particularly U. delphinus, showed a markedly subdued response. Notably, U. pictorum's northern population relied heavily on the cytochrome P450 family even at moderate temperatures, while the southern populations of both species activated broader proteostasis and immune responses at higher stress thresholds.
These findings demonstrate clear population-specific phenotypic plasticity, shaped by environmental conditions rather than phylogenetic proximity. They underscore the need for conservation strategies to move beyond species-level management, embracing intraspecific variation as a buffer against climate impacts. As climate change accelerates, safeguarding the evolutionary potential encoded within populations, not just species, is essential to preserving biodiversity resilience.
The gill transcriptome of threatened European freshwater mussels
Publication . Gomes-dos-Santos, André; Machado, André M.; Castro, L. Filipe C.; Prié, Vincent; Teixeira, Amílcar; Lopes-Lima, Manuel; Froufe, Elsa
Genomic tools applied to non-model organisms are critical to design successful conservation
strategies of particularly threatened groups. Freshwater mussels of the Unionida order are among
the most vulnerable taxa and yet almost no genetic resources are available. Here, we present the gill
transcriptomes of five European freshwater mussels with high conservation concern: Margaritifera
margaritifera, Unio crassus, Unio pictorum, Unio mancus and Unio delphinus. The final assemblies, with
N50 values ranging from 1069–1895 bp and total BUSCO scores above 90% (Eukaryote and Metazoan
databases), were structurally and functionally annotated, and made available. The transcriptomes here
produced represent a valuable resource for future studies on these species’ biology and ultimately guide
their conservation.
The silent extinction of freshwater mussels in Portugal
Publication . Lopes-Lima, Manuel; Reis, Joaquim; Alvarez, Maria G.; Anastácio, Pedro M.; Banha, Filipe; Beja, Pedro; Castro, Paulo S.; Gama, Mafalda; Gil, Maria G.; Gomes-dos-Santos, André; Miranda, Fernando Jorge Veloso; Nogueira, Joana Garrido; Sousa, Ronaldo; Teixeira, Amílcar; Varandas, Simone; Froufe, Elsa
Freshwater mussels are one of the most threatened animal groups in the world. In the European Union,
threatened and protected mussel species are not adequately monitored, while species considered to be common
and widespread receive even less attention. This is particularly worrying in the Mediterranean region, where
species endemism is high and freshwater habitats are severely affected by water scarcity. In the absence of hard
data on population trends, we report here a long-term comparison of freshwater mussel assemblages at 132 sites
covering 15 different hydrological basins in Portugal. This study reveals a widespread decline of 60 % in the
number of sites and 67 % in the overall abundance of freshwater mussels across Portugal over the last 20 years,
indicating that all species are rapidly declining and threatened with extinction. These results show that current
legislation and conservation measures are largely ineffective and highlight the importance of updating the
Habitats Directive to enforce standard monitoring protocols for threatened species in the European Union and to
extend monitoring to other freshwater species thought to be common and widespread. Efficient water management,
restrictions on irrigation expansion in important biodiversity areas, mitigation of hydrological changes
and loss of aquatic habitat connectivity caused by physical alterations are urgently needed to reverse these
declining population trends. For the severely endangered species Margaritifera margaritifera, Potomida littoralis,
and Unio tumidiformis, where populations are now critically low, more urgent action is needed, such as ex-situ
conservation, protection of remaining populations and large-scale habitat restoration.
Unidades organizacionais
Descrição
Palavras-chave
Contribuidores
Financiadores
Entidade financiadora
Fundação para a Ciência e a Tecnologia
Programa de financiamento
Concurso para Financiamento de Projetos de Investigação Científica e Desenvolvimento Tecnológico em Todos os Domínios Científicos - 2020
Número da atribuição
PTDC/CTA-AMB/3065/2020