{"title":"Bridging the gap between genomic, phenotypic, and modeling data in picophytoplankton-virus interactions.","authors":"Luisa Listmann, Carina Peters, Anais Labecot, Raphaël Rousseau, Christie Baux, Maria Elisabetta Santelia, Eric Manirakiza, Nigel Grimsley, Sheree Yau, Sébastien Gourbiere, C-Elisa Schaum, Gwenael Piganeau","doi":"10.1111/jpy.70229","DOIUrl":"https://doi.org/10.1111/jpy.70229","url":null,"abstract":"<p><p>We present a comprehensive synthesis of recent developments in methodological approaches to combine experimental and genomic studies of picophytoplankton-virus interactions. This synthesis will not only enhance our understanding of these relationships but also stimulate new hypotheses for the interpretation of metagenomic data and enrich current modeling efforts. Marine picophytoplankton are significant primary producers despite their low contribution to biomass. Pan-oceanic metagenomic studies have revealed an astounding genetic diversity within these communities and the astronomical abundance of viruses that infect them. Despite recent advances in understanding the genetic and genomic diversity of picophytoplankton and viruses, the interpretation of these data relies heavily on ecological and physiological insights. Specifically, our understanding of the mechanisms and dynamics governing host-virus interactions is limited because the current wealth of sequence data has not yet been matched with corresponding life-history traits. Linking phenotypes to genotypes in picophytoplankton-virus systems is also essential for accurately modeling their interactions and their impact on the global carbon cycle. Ultimately, the synergy of the three domains allows for a mechanistic interpretation of environmental data.</p>","PeriodicalId":16831,"journal":{"name":"Journal of Phycology","volume":" ","pages":""},"PeriodicalIF":4.3,"publicationDate":"2026-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148977137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Em G Lim, Claire M Attridge, Kiara R Kattler, Brittnie Spriel, Isabelle M Côté
{"title":"Macroalgae respond to consumer-mediated nutrient cycling in a temperate ecosystem.","authors":"Em G Lim, Claire M Attridge, Kiara R Kattler, Brittnie Spriel, Isabelle M Côté","doi":"10.1111/jpy.70233","DOIUrl":"https://doi.org/10.1111/jpy.70233","url":null,"abstract":"<p><p>Primary production in coastal upwelling regions has often been presumed to be supported primarily by allochthonous nutrients, but inconsistent nutrient delivery and the metabolic cost of nitrate assimilation can leave producers nitrogen limited during the growing season. As a potential supplement for insufficient allochthonous supply, nutrient provisioning through the metabolic wastes of animals, termed consumer-mediated nutrient cycling (CNC), provides easily assimilated nitrogen in the form of ammonium. Although it has been suggested that CNC sustains macroalgal growth on the west coast of North America, experimental fertilization experiments, especially on kelps, are lacking. Here, we measured the growth rates of winged kelp (Alaria marginata) and sea lettuce (Ulva sp.) under ammonium levels that varied experimentally in the laboratory as well as naturally across sites in the wild. We observed evidence that in the field, a regionally high-nitrate environment, elevated ammonium was associated with 1.4× higher growth and 1.2× higher percent nitrogen content in A. marginata. Using in situ mesocosms, we observed that Ulva grew 3.8× faster and had 1.4× higher internal nitrogen concentration when exposed to nitrogen-rich excretion from red rock crabs (Cancer productus). Our study suggests kelps growing in low ammonium but higher nitrate conditions may be nitrogen limited, suggesting that nitrates from allochthonous sources may not meet the nutrient requirements of macroalgae in this moderate upwelling ecosystem. Therefore, nutrient regeneration by animals may be an important source of nitrogen across varying levels of allochthonous nitrate supply.</p>","PeriodicalId":16831,"journal":{"name":"Journal of Phycology","volume":" ","pages":""},"PeriodicalIF":4.3,"publicationDate":"2026-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148919721","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lauren N Dykman, S Clay Steell, Amanda Zielinski, Rob Zielinski, Alexandra Saunders-Wiebe, Matthew Csordas, Julia K Baum, Christopher J Neufeld
{"title":"Identifying thermally tolerant bull kelp (Nereocystis luetkeana) source populations for restoration under climate change.","authors":"Lauren N Dykman, S Clay Steell, Amanda Zielinski, Rob Zielinski, Alexandra Saunders-Wiebe, Matthew Csordas, Julia K Baum, Christopher J Neufeld","doi":"10.1111/jpy.70232","DOIUrl":"https://doi.org/10.1111/jpy.70232","url":null,"abstract":"<p><p>Kelp forests are declining in many parts of the world due to climate change and other stressors. Restoration is one solution to return kelp forests to places where they have been lost, yet continually warming oceans may necessitate the identification of thermally tolerant strains to facilitate the long-term success of kelp restoration. The Salish Sea is a waterway in British Columbia, Canada, and Washington State, United States, where ocean temperatures increasingly exceed the thermal limit for bull kelp (Nereocystis luetkeana), causing substantial losses along parts of its range. To identify thermally tolerant source material, we cultured bull kelp sourced from five populations along a thermal gradient in the northern Salish Sea and outplanted them in a common garden experiment at a warm site where bull kelp has been extirpated: Maude Reef on Hornby Island. We tracked stipe length, blade elongation, blade condition, sorus formation, and persistence. Kelp from the nearest cool site reached the largest sizes overall and produced the most sori. In the warm summer, kelp from the nearest warm site had significantly greater blade elongation rates and persisted longer than kelp from distant sites. Blade opacity did not show any distinct pattern, suggesting that loss of photosynthetic pigmentation is likely not the mechanism or consequence of observed differences in growth rate. Significant population-level variation in growth and blade condition may hint at possible adaptive strategies for heat avoidance in bull kelp. From these findings, we suggest population sourcing or mixture strategies that may increase restoration success.</p>","PeriodicalId":16831,"journal":{"name":"Journal of Phycology","volume":" ","pages":""},"PeriodicalIF":4.3,"publicationDate":"2026-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148919610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Genome-scale insights into metabolic streamlining and photosynthetic energy balance in the extremophile green alga Picocystis salinarum (Picocystophyceae, Chlorophyta).","authors":"Claude Lemieux, Christian Otis, Monique Turmel","doi":"10.1111/jpy.70235","DOIUrl":"https://doi.org/10.1111/jpy.70235","url":null,"abstract":"<p><p>Picocystis salinarum is an early-diverging chlorophyte and the sole described member of the Picocystophyceae, frequently dominating hypersaline and alkaline lakes despite extreme physicochemical constraints. To elucidate the genomic foundations of its ecological success, we generated a fully annotated, chromosome-scale nuclear genome assembly of the type strain originally isolated from a saline pond in San Francisco Bay. The 18.5-Mb genome comprises 30 chromosomal assemblies, exhibits clear diploidy, and contains multiple copies of intact Ty3/Gypsy and Ty1/Copia long terminal repeat retrotransposons encoding polyproteins with atypical accessory domains. Phylogenomic analyses reveal strong affinity with the Nephroselmidophyceae. Comparative analyses reveal extensive metabolic streamlining, including the absence of a queuosine salvage pathway, the 2-methylcitrate cycle, β-oxidation of propionate, and branched-chain amino acid catabolism, traits retained in several marine prasinophyte lineages. In contrast, the genome preserves multiple ancestral bacterial derived systems. Notably, P. salinarum features a complete chloroplast NADH dehydrogenase-like complex, including all membrane, electron binding, and assembly components, a configuration not previously reported in sequenced chlorophyte algae. This retention implies substantial capacity for cyclic electron flow and chlororespiration, processes expected to be critical in chronically low-light and chemically extreme environments. The genome further reveals a distinctive biochemical CO<sub>2</sub>-concentrating mechanism centered on plastid-targeted phosphoenolpyruvate carboxykinase, complete plastid peptidoglycan biosynthetic and remodeling pathways, and partial retention of lipid-A-related machinery. Conversely, P. salinarum lacks canonical non-photochemical quenching proteins while retaining xanthophyll-cycle enzymes that support slower photoprotective responses. Together, these features define a coordinated genomic architecture that underpins the specialization of P. salinarum to hypersaline, alkaline, and persistently low-light ecosystems.</p>","PeriodicalId":16831,"journal":{"name":"Journal of Phycology","volume":" ","pages":""},"PeriodicalIF":4.3,"publicationDate":"2026-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148919560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Myung Jin Hyun, Howon Lee, Antonio Mannino, Crystal Thomas, Young-Je Park, Jongkuk Choi, Dong Han Choi, Taekeun Rho, Joaquim I Goes, Charity Mijin Lee, Yeonjung Lee, Jae-Hoon Noh
{"title":"Mechanism-based clustering reveals distinct controls on phytoplankton community composition across Korean marginal seas from integrated in situ and satellite observations (KORUS-OC 2016).","authors":"Myung Jin Hyun, Howon Lee, Antonio Mannino, Crystal Thomas, Young-Je Park, Jongkuk Choi, Dong Han Choi, Taekeun Rho, Joaquim I Goes, Charity Mijin Lee, Yeonjung Lee, Jae-Hoon Noh","doi":"10.1111/jpy.70226","DOIUrl":"https://doi.org/10.1111/jpy.70226","url":null,"abstract":"<p><p>Phytoplankton regulate the marine food web, biogeochemical processes, and climate-relevant carbon export to depth in the oceans, but the mechanisms controlling their distributions vary across space and time, limiting inference from pooled analyses. We developed a mechanism-based clustering framework that groups stations by covariate-community response fingerprints inferred from a multivariate generalized linear mixed model (GLMM). Station-specific random effects across major taxa were treated as fingerprints and clustered to define mechanism-consistent groups; Geostationary Ocean Color Imager (GOCI) satellite time series were analyzed with dynamic factor analysis (DFA) to provide complementary dynamical context. Applied to spring observations in the Korean marginal seas, GLMM-fingerprint clustering identified four clusters and increased redundancy analysis explanatory power relative to both the pooled data set (adjusted R<sup>2</sup> = 0.221) and a composition-based clustering baseline. Phytoplankton community composition was most closely related to stratification in the Yellow Sea, mesoscale eddy/upwelling forcing in the East Sea, and contrasting warm-current versus freshwater influences in the South Sea. The Yellow Sea cluster showed strong coherence with stratification-related controls (adjusted R<sup>2</sup> = 0.847). Explanatory power remained lower in the East Sea cluster (adjusted R<sup>2</sup> = 0.272), consistent with mesoscale forcing that is difficult to capture using field covariates alone, whereas DFA-based satellite diagnostics supported eddy/upwelling-related variability. The South Sea separated into two clusters (adjusted R<sup>2</sup> = 0.492 and 0.424), reflecting contrasting warm-current versus freshwater influences. This framework offers an interpretable pathway for mechanism-oriented regionalization in dynamically complex coastal seas.</p>","PeriodicalId":16831,"journal":{"name":"Journal of Phycology","volume":" ","pages":""},"PeriodicalIF":4.3,"publicationDate":"2026-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148912387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sandra Rabow, Shenghe Cai, Per Carlsson, Karin Rengefors
{"title":"Earlier spring may explain dominance of the slow-growing dinoflagellate Naiadinium polonicum over the cyanobacterium Microcystis during a heatwave.","authors":"Sandra Rabow, Shenghe Cai, Per Carlsson, Karin Rengefors","doi":"10.1111/jpy.70228","DOIUrl":"https://doi.org/10.1111/jpy.70228","url":null,"abstract":"<p><p>Global warming and extreme weather events have been linked to a rise in cyanobacterial blooms, which threaten water quality and ecosystem services. However, during an extreme hot and dry summer, Microcystis was outcompeted by a dinoflagellate, Naiadinium polonicum, in a drinking water lake in southern Sweden. Surface water temperatures were particularly high in May and July, peaking at 18.7 and 24.3°C, respectively. A 3-year field study of the lake further revealed surface water temperature to be a strong predictor of N. polonicum biomass, but not Microcystis biomass. To investigate the mechanisms underlying the success of N. polonicum over Microcystis in 2018, we examined the direct effects of temperature on the recruitment and growth rates of both species. Recruitment experiments were conducted using lake sediments containing resting stages, while growth rate experiments used strains of both species isolated from the lake. Recruitment of N. polonicum was temperature dependent, declining at temperatures above 12°C, whereas its growth rate peaked at 20°C. In contrast, Microcystis recruitment was unaffected by temperature, with optimal growth at the highest temperature used in this study, 28°C. We conclude that the extreme heatwave acted as an \"early spring,\" advancing the recruitment window for N. polonicum but not for Microcystis. This shift in timing gave the slower-growing dinoflagellate a crucial head start, allowing it to accumulate biomass and dominate the community before peak summer temperatures set in. These findings highlight how climate-induced shifts in temperature regimes can restructure phytoplankton communities, altering bloom dynamics in unpredictable ways.</p>","PeriodicalId":16831,"journal":{"name":"Journal of Phycology","volume":" ","pages":""},"PeriodicalIF":4.3,"publicationDate":"2026-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148891912","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Julia Van Etten, Sungpil Han, John A Burns, Duckhyun Lhee, Andrew C Willoughby, Timothy G Stephens, Erin Chille, Robin S Sleith, Debashish Bhattacharya, Hwan Su Yoon
{"title":"Crawling under the radar: Two novel Paulinella species expand knowledge about the ecology and evolution of a primary plastid-containing amoeba lineage.","authors":"Julia Van Etten, Sungpil Han, John A Burns, Duckhyun Lhee, Andrew C Willoughby, Timothy G Stephens, Erin Chille, Robin S Sleith, Debashish Bhattacharya, Hwan Su Yoon","doi":"10.1111/jpy.70230","DOIUrl":"https://doi.org/10.1111/jpy.70230","url":null,"abstract":"<p><p>The genus Paulinella represents a rare, independent case of primary endosymbiosis, providing a unique system to study the early stages of organelle evolution. Here, we expand current understanding of primary plastid endosymbiosis through the discovery and characterization of two novel photosynthetic amoebae, Paulinella marae sp. nov. and Paulinella murrayi sp. nov., isolated from a brackish water habitat in North Carolina, United States. Complete chromatophore genomes and mitochondrial data revealed conserved gene content but notable structural variation, including genome rearrangements and inversion events. Phylogenetic analyses uncovered significant discordance between nuclear and organelle datasets, likely driven by substitution saturation, limited taxon sampling, and differing evolutionary signals across loci. Ecological observations over multiple years indicate that both species are in low abundance but consistently present, and when coupled with hobbyist data, support the hypothesis that photosynthetic Paulinella species are globally distributed yet under-sampled. These results increase known species diversity within the clade from four to six and highlight the importance of integrating field-based observations with genomic approaches. Overall, this work advances Paulinella as a model for studying ongoing primary endosymbiosis, lineage divergence, and the ecological strategies of low-abundance microbial eukaryotes.</p>","PeriodicalId":16831,"journal":{"name":"Journal of Phycology","volume":" ","pages":""},"PeriodicalIF":4.3,"publicationDate":"2026-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148891846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Petr Knotek, Iva Jadrná, Martin Pusztai, Pavel Škaloud
{"title":"Comprehensive revision of Mallomonas sect. Peroneides stat. nov. (Chrysophyceae) integrating morphology and multigene phylogeny.","authors":"Petr Knotek, Iva Jadrná, Martin Pusztai, Pavel Škaloud","doi":"10.1111/jpy.70224","DOIUrl":"https://doi.org/10.1111/jpy.70224","url":null,"abstract":"<p><p>Mallomonas is among the most diverse genera of Chrysophyceae, yet many of its lineages remain taxonomically unresolved due to limited molecular sampling. Mallomonas series Peronoides, historically limited to four species, has posed persistent taxonomic difficulties, most notably the long-standing and problematic reliance on a rare hemispherical structure to distinguish M. bangladeshica from M. peroneides. Here, we present a comprehensive revision of Mallomonas section Peroneides stat. nov., formerly treated as ser. Peronoides, that integrates detailed morphological analyses with a five-gene phylogeny. Thirty-one strains isolated from 15 freshwater sites across five countries resolved into seven well-supported clades based on the nuclear ribosomal internal transcribed spacer (ITS) DNA region. Four corresponded to previously described species (M. bangladeshica, M. ceylanica, M. peroneides, M. stellata), whereas three represente novel taxa: M. cotyloides sp. nov., M. neotropica sp. nov., and M. palmata sp. nov. Morphological reassessment, including original iconotypes, identified reliable diagnostic characters in scale architecture; secondary layer distribution; and experimentally confirmed, temperature-dependent formation of the hemispherical structure. Phylogenetic analyses revealed two deeply divergent lineages within the section, reflecting distinct evolutionary trajectories in central depression morphology and scale diversification. Biogeographic and ecological data indicated a primary association with warm, humic freshwater habitats, although several taxa tolerate markedly cooler conditions. Together, these results refine species boundaries, resolve long-standing taxonomic ambiguities, and establish a robust framework for future taxonomic, phylogenetic, and ecological research on Mallomonas.</p>","PeriodicalId":16831,"journal":{"name":"Journal of Phycology","volume":" ","pages":""},"PeriodicalIF":4.3,"publicationDate":"2026-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148865564","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Journal of PhycologyPub Date : 2026-08-18Epub Date: 2026-06-22DOI: 10.1111/jpy.70187
Jane M. Edgeloe, Samuel Starko, Georgina V. Wood, Albert Pessarrodona, Antoine J. P. Minne, Thomas Wernberg
{"title":"Complete organellar genomes of Cystophora brownii: Insights into mitochondrial and plastid structure and evolution in brown algae","authors":"Jane M. Edgeloe, Samuel Starko, Georgina V. Wood, Albert Pessarrodona, Antoine J. P. Minne, Thomas Wernberg","doi":"10.1111/jpy.70187","DOIUrl":"10.1111/jpy.70187","url":null,"abstract":"<p><i>Cystophora</i> (order Fucales) is one of the most diverse genera of habitat-forming brown algae and is endemic to temperate reefs of Australia and New Zealand. Species in this genus form complex habitat structures that support diverse marine communities and contribute to coastal productivity. However, <i>Cystophora</i> spp. are highly sensitive to environmental stress, and recent declines across parts of their historical range highlight their vulnerability to ocean warming. Despite their ecological importance, genomic resources for <i>Cystophora</i> remain scarce, limiting insight into their evolutionary history, adaptive capacity, and resilience to environmental change. Here, we sequenced, assembled, and annotated the complete plastid and mitochondrial genomes of the widespread species <i>Cystophora brownii</i> using PacBio HiFi long-read sequencing. We characterized organellar genome architecture and gene content, conducted comparative analyses with other Fucalean taxa, and reconstructed phylogenetic relationships within the Fucales. The mitochondrial genome is 36,047 bp and contains 66 conserved genes (GenBank accession PZ196221). The plastid genome is 124,536 bp and contains 171 conserved genes, including two inverted repeat regions (GenBank accession PX975689). Comparative analyses indicate conserved gene content, order, and structure relative to other Fucalean organellar genomes. Maximum likelihood phylogenetic analyses robustly place <i>C. brownii</i> within the Fucales with strong support, resolving it as sister to the remaining Sargassaceae, suggesting an early divergence within the family that may date to the Miocene. These genomic resources provide a foundation for resolving the evolutionary placement of <i>Cystophora</i> and advancing studies of organellar genome evolution in brown algae.</p>","PeriodicalId":16831,"journal":{"name":"Journal of Phycology","volume":"62 4","pages":"1193-1203"},"PeriodicalIF":4.3,"publicationDate":"2026-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/jpy.70187","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148302165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Journal of PhycologyPub Date : 2026-08-18Epub Date: 2026-06-17DOI: 10.1111/jpy.70191
Maisie R. Roy-Musor, Christa Agoawike, A. Lacey Samuels, Patrick T. Martone
{"title":"Holdfast adhesion in the kelp Alaria marginata: Cell wall polysaccharides and phenolics","authors":"Maisie R. Roy-Musor, Christa Agoawike, A. Lacey Samuels, Patrick T. Martone","doi":"10.1111/jpy.70191","DOIUrl":"10.1111/jpy.70191","url":null,"abstract":"<p>Adhesion is a critical process in the survival of seaweeds, especially in wave-swept environments. Kelp (Laminariales) sporophytes secrete adhesives from specialized rhizoid cells to anchor themselves to the substrate and withstand immense forces applied by waves. Although the composition of macroalgal adhesive has been described primarily in the Fucales, the current adhesive model is incomplete, and similarities between kelp and fucoid adhesives are unknown. Moreover, the cellular organization of the attachment interface of kelps is poorly understood. In this study, we examined the composition of rhizoid cells and adhesive from developing holdfasts of the kelp <i>Alaria marginata</i> using brightfield, fluorescence, and scanning electron microscopy. Rhizoid cells form a thick, intertwined mat cemented with adhesive. We provide the highest resolution immunofluorescent analysis of kelp adhesives to date using confocal microscopy: Kelp adhesives are composed of fucose-containing sulfated polysaccharides (FCSPs) and alginate, dominated by BAM3 and BAM4 epitopes. Holdfast adhesives are biochemical extensions of the cell wall with distinct composition from the wall proper. This work advances our basic understanding of kelp adhesion and highlights gaps in our current understanding of adhesive composition, raising questions, for example, about the roles of phenolics and proteins. Biochemical and histological methods presented here set the stage for future examination of the developmental, ecological, and evolutionary dynamics of adhesion.</p>","PeriodicalId":16831,"journal":{"name":"Journal of Phycology","volume":"62 4","pages":"1344-1355"},"PeriodicalIF":4.3,"publicationDate":"2026-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/jpy.70191","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148264856","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}