Evolutionary genomics of the emergence of brown algae as key components of coastal ecosystems.

Brown seaweeds are keystone species of coastal ecosystems, often forming extensive underwater forests, and are under considerable threat from climate change. In this study, analysis of multiple genomes has provided insights across the entire evolutionary history of this lineage, from initial emergence, through later diversification of the brown algal orders, down to microevolutionary events at the genus level. Emergence of the brown algal lineage was associated with a marked gain of new orthologous gene families, enhanced protein domain rearrangement, increased horizontal gene transfer events, and the acquisition of novel signaling molecules and key metabolic pathways, the latter notably related to biosynthesis of the alginate-based extracellular matrix, and halogen and phlorotannin biosynthesis.

Of sea, rivers and symbiosis: Diversity, systematics, biogeography and evolution of the deeply diverging florideophycean order Hildenbrandiales (Rhodophyta).

The Hildenbrandiales, a typically saxicolous red algal order, is an early diverging florideophycean group with global significance in marine and freshwater ecosystems across diverse temperature zones. To comprehensively elucidate the diversity, phylogeny, biogeography, and evolution of this order, we conducted a thorough re-examination employing molecular data derived from nearly 700 specimens. Employing a species delimitation method, we identified Evolutionary Species Units (ESUs) within the Hildenbrandiales aiming to enhance our understanding of species diversity and generate the first time-calibrated tree and ancestral area reconstruction for this order.

French Polynesian Scytosiphonaceae (Ectocarpales, Phaeophyceae): A combined molecular and morphological approach to their diversity and systematics.

This study revisited the taxonomy and diversity of brown macroalgae within the Scytosiphonaceae family in French Polynesia, which had previously been recognized as encompassing only six species. Using the chloroplast and mitochondrial genes rbcL, psbA, and cox3 as molecular markers in conjunction with morpho-anatomical observations, we unveiled the presence of 11 species spanning six genera: Chnoospora minima, Colpomenia claytoniae, Co. sinuosa [groups IIIa and IIIb], Hydroclathrus rapanuii, H.

Marine Flora of French Polynesia: An Updated List Using DNA Barcoding and Traditional Approaches.

Located in the heart of the South Pacific Ocean, the French Polynesian islands represent a remarkable setting for biological colonization and diversification, because of their isolation. Our knowledge of this region's biodiversity is nevertheless still incomplete for many groups of organisms. In the late 1990s and 2000s, a series of publications provided the first checklists of French Polynesian marine algae, including the Chlorophyta, Rhodophyta, Ochrophyta, and Cyanobacteria, established mostly on traditional morphology-based taxonomy.

Marine Floral Biodiversity, Threats, and Conservation in Vietnam: An Updated Review.

Part of the Indo-Chinese peninsula and located on the northwest edge of the Coral Triangle in the South China Sea, the Vietnamese coastal zone is home to a wealthy marine biodiversity associated with the regional geological setting and history, which supports a large number of marine ecosystems along a subtropical to tropical gradient. The diversity of coastal benthic marine primary producers is also a key biological factor supporting marine biological diversity. The present review provides: (1) an updated checklist of the Vietnamese marine flora, (2) a review of molecular-assisted alpha taxonomic efforts, (3) an analysis of marine floral biodiversity spatial distribution nationally and regionally (South China Sea), (4) a review of the impact of anthropogenic and environmental stressors on the Vietnamese marine flora, and (5) the efforts developed in the last decade for its conservation.

Diversity and Ecology of Species Associated with Coral Reef Systems in the Western Gulf of Thailand, including the Description of Two New Species.

The brown macroalgal genus plays important ecological roles in many marine ecosystems. This group has received much attention over the past decade, and a considerable number of new species have been identified globally. However, our knowledge of the genus diversity and ecology along south-east Asian coasts are still limited.

Whole genome population structure of North Atlantic kelp confirms high-latitude glacial refugia.

Coastal refugia during the Last Glacial Maximum (~21,000 years ago) have been hypothesized at high latitudes in the North Atlantic, suggesting marine populations persisted through cycles of glaciation and are potentially adapted to local environments. Here, whole-genome sequencing was used to test whether North Atlantic marine coastal populations of the kelp Alaria esculenta survived in the area of southwestern Greenland during the Last Glacial Maximum. We present the first annotated genome for A.

Providing a phylogenetic framework for trait-based analyses in brown algae: Phylogenomic tree inferred from 32 nuclear protein-coding sequences.

In the study of the evolution of biological complexity, a reliable phylogenetic framework is needed. Many attempts have been made to resolve phylogenetic relationships between higher groups (i.e.

Whole-genome sequencing reveals forgotten lineages and recurrent hybridizations within the kelp genus Alaria (Phaeophyceae).

The genomic era continues to revolutionize our understanding of the evolution of biodiversity. In phycology, emphasis remains on assembling nuclear and organellar genomes, leaving the full potential of genomic datasets to answer long-standing questions about the evolution of biodiversity largely unexplored. Here, we used whole-genome sequencing (WGS) datasets to survey species diversity in the kelp genus Alaria, compare phylogenetic signals across organellar and nuclear genomes, and specifically test whether phylogenies behave like trees or networks.

Taxonomy and toxicity of a bloom-forming Ostreopsis species (Dinophyceae, Gonyaulacales) in Tahiti island (South Pacific Ocean): one step further towards resolving the identity of O. siamensis.

Among dinoflagellates responsible for benthic harmful algal blooms, the genus Ostreopsis primarily described from tropical areas has been increasingly reported from subtropical and temperate areas worldwide. Several species of this toxigenic genus produce analogs of palytoxin, thus representing a major threat to human and environmental health. The taxonomy of several species needs to be clarified as it was based mostly on morphological descriptions leading in some cases to ambiguous interpretations and misidentifications.

Radiation of the coralline red algae (Corallinophycidae, Rhodophyta) crown group as inferred from a multilocus time-calibrated phylogeny.

The subclass Corallinophycidae is the only group of red algae characterized by the presence of calcite crystals in their cell walls. Except for the Rhodogorgonales, the remaining orders - collectively called corallines - are diverse and widely distributed, having calcified cell walls and highly variable morphology. Corallines constitute the group with the richest fossil record among marine algae.

Diversity, Ecology, Biogeography, and Evolution of the Prevalent Brown Algal Genus Lobophora in the Greater Caribbean Sea, Including the Description of Five New Species.

Distributed in tropical and warm-temperate waters worldwide, Lobophora species are found across the Greater Caribbean (i.e., Caribbean sensu stricto, Gulf of Mexico, Florida, the Bahamas, and Bermuda).

Lobophora (Dictyotales) Species Richness, Ecology and Biogeography Across the North-Eastern Atlantic Archipelagos and Description of Two New Species.

The brown alga Lobophora (Dictyotales, Phaeophyceae) is an important macroalga in the North-eastern Atlantic archipelagos (i.e., Macaronesia).

The systematics of Lobophora (Dictyotales, Phaeophyceae) in the western Atlantic and eastern Pacific oceans: eight new species.

Lobophora is a common tropical to temperate genus of brown algae found in a plethora of habitats including shallow and deep-water coral reefs, rocky shores, mangroves, seagrass beds, and rhodoliths beds. Recent molecular studies have revealed that Lobophora species diversity has been severely underestimated. Current estimates of the species numbers range from 100 to 140 species with a suggested center of diversity in the Central Indo-Pacific.

High metabolic variation for seaweeds in response to environmental changes: a case study of the brown algae Lobophora in coral reefs.

In the marine environment, macroalgae face changing environmental conditions and some species are known for their high capacity to adapt to the new factors of their ecological niche. Some macroalgal metabolites play diverse ecological functions and belong to the adaptive traits of such species. Because algal metabolites are involved in many processes that shape marine biodiversity, understanding their sources of variation and regulation is therefore of utmost relevance.

Historical biogeography of the highly diverse brown seaweed Lobophora (Dictyotales, Phaeophyceae).

The tropical to warm-temperate marine brown macroalgal genus Lobophora (Dictyotales, Phaeophyceae) recently drew attention because of its striking regional diversity. In this study we reassess Lobophora global species diversity, and species distributions, and explore how historical factors have shaped current diversity patterns. We applied a series of algorithmic species delineation techniques on a global mitochondrial cox3 dataset of 598 specimens, resulting in an estimation of 98-121 species.

Species Specificity of Bacteria Associated to the Brown Seaweeds Lobophora (Dictyotales, Phaeophyceae) and Their Potential for Induction of Rapid Coral Bleaching in Acropora muricata.

While reef degradation is occurring worldwide, it is not uncommon to see phase shifts from coral to macroalgal dominated reefs. Numerous studies have addressed the mechanisms by which macroalgae may outcompete corals and a few recent studies highlighted the putative role of bacteria at the interface between macroalgae and corals. Some studies suggest that macroalgae may act as vectors and/or foster proliferation of microorganisms pathogenic for corals.

Allelopathic interactions between the brown algal genus Lobophora (Dictyotales, Phaeophyceae) and scleractinian corals.

Allelopathy has been recently suggested as a mechanism by which macroalgae may outcompete corals in damaged reefs. Members of the brown algal genus Lobophora are commonly observed in close contact with scleractinian corals and have been considered responsible for negative effects of macroalgae to scleractinian corals. Recent field assays have suggested the potential role of chemical mediators in this interaction.

Substrates specialization in lipid compounds and hydrocarbons of Marinobacter genus.

The impact of petroleum contamination and of burrowing macrofauna on abundances of Marinobacter and denitrifiers was tested in marine sediment mesocoms after 3 months incubation. Quantification of this genus by qPCR with a new primer set showed that the main factor favoring Marinobacter abundance was hydrocarbon amendment followed by macrofauna presence. In parallel, proportion of nosZ-harboring bacteria increased in the presence of marcrofauna.

Toward an inordinate fondness for stars, beetles and Lobophora? Species diversity of the genus Lobophora (Dictyotales, Phaeophyceae) in New Caledonia.

Until the recent use of molecular markers, species diversity of Lobophora, an ecologically important brown algal genus with a worldwide distribution in temperate and tropical seas, has been critically underestimated. Using a DNA-based taxonomic approach, we re-examined diversity of the genus from New Caledonia in the Southwest Pacific Ocean. First, species were delineated using general mixed Yule coalescent-based and barcoding gap approaches applied to a mitochondrial cox3 data set.