Pub Date : 2023-04-03DOI: 10.1080/09670262.2023.2183990
Thoriq Teja Samudra, Hiroaki Takahashi, Y. Amano, M. Machida
ABSTRACT Cyanobacterial blooms are widely known to cause problems in the aquatic environment, and their appearance has become more frequent due to global warming. Microcystis is one of the most widespread and dominant bloom-forming cyanobacterial genera, largely because Microcystis has the ability to control its buoyancy. A buoyancy experiment conducted on Microcystis sp. isolated from cyanobacterial blooms in Lake Senba, Japan, showed that buoyancy could be controlled using a combination of preculture under the dark conditions and the addition of powdered tightly bound extracellular polysaccharides (TB-EPS) and metal cations (Ca2+ and Mg2+). Preculture under the dark conditions, 96 h in length were the most effective treatment to reduce the cellular carbohydrate content of Microcystis and simultaneously increase its buoyancy. The addition of TB-EPS, Ca2+ and Mg2+ ions increased the colony size of Microcystis and enhanced buoyancy in precultures under both dark and light conditions. Thus, the buoyancy of Microcystis can be controlled by reducing its cellular carbohydrate content by preculturing it in dark conditions for 96 h and increasing the colony size with the addition of 100 mg l−1 EPS, 80 mg l−1 Ca2+ and 80 mg l−1 Mg2+. This study contributes to establishing a novel removal method for cyanobacterial blooms dominated by Microcystis, especially in water treatment facilities. HIGHLIGHTS • Microcystis buoyancy was controlled by decreasing cellular carbohydrate content using preculture under dark conditions. • The addition of TB-EPS, Ca2+ and Mg2+ ions increased the colony size of Microcystis and enhanced the buoyancy in precultures under both dark and light conditions. • This represents a novel removal method for cyanobacterial blooms in water treatment facilities.
{"title":"Buoyancy control of Microcystis using different light regimes combined with extracellular polysaccharides and cationic ions","authors":"Thoriq Teja Samudra, Hiroaki Takahashi, Y. Amano, M. Machida","doi":"10.1080/09670262.2023.2183990","DOIUrl":"https://doi.org/10.1080/09670262.2023.2183990","url":null,"abstract":"ABSTRACT Cyanobacterial blooms are widely known to cause problems in the aquatic environment, and their appearance has become more frequent due to global warming. Microcystis is one of the most widespread and dominant bloom-forming cyanobacterial genera, largely because Microcystis has the ability to control its buoyancy. A buoyancy experiment conducted on Microcystis sp. isolated from cyanobacterial blooms in Lake Senba, Japan, showed that buoyancy could be controlled using a combination of preculture under the dark conditions and the addition of powdered tightly bound extracellular polysaccharides (TB-EPS) and metal cations (Ca2+ and Mg2+). Preculture under the dark conditions, 96 h in length were the most effective treatment to reduce the cellular carbohydrate content of Microcystis and simultaneously increase its buoyancy. The addition of TB-EPS, Ca2+ and Mg2+ ions increased the colony size of Microcystis and enhanced buoyancy in precultures under both dark and light conditions. Thus, the buoyancy of Microcystis can be controlled by reducing its cellular carbohydrate content by preculturing it in dark conditions for 96 h and increasing the colony size with the addition of 100 mg l−1 EPS, 80 mg l−1 Ca2+ and 80 mg l−1 Mg2+. This study contributes to establishing a novel removal method for cyanobacterial blooms dominated by Microcystis, especially in water treatment facilities. HIGHLIGHTS • Microcystis buoyancy was controlled by decreasing cellular carbohydrate content using preculture under dark conditions. • The addition of TB-EPS, Ca2+ and Mg2+ ions increased the colony size of Microcystis and enhanced the buoyancy in precultures under both dark and light conditions. • This represents a novel removal method for cyanobacterial blooms in water treatment facilities.","PeriodicalId":12032,"journal":{"name":"European Journal of Phycology","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45450290","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-28DOI: 10.1080/09670262.2023.2183265
H. Kawai, Kazusa Takeuchi, T. Hanyuda, J. Brodie, Robert J. Mrowicki, K. Miller, W. Nelson
ABSTRACT A molecular phylogeny of Tinocladia and Eudesme based on specimens covering a large proportion of the known species was done using mitochondrial cox1 and cox3, chloroplast atpB, psaA, psbA and rbcL genes and 5.8S rDNA and its ITS2 region sequences. The phylogeny revealed a close phylogenetic relationship between the two genera and the occurrence of a cryptic species within the generitype T. crassa. Eudesme species (E. borealis, E. shandongensis and the generitype E. virescens) showed a sister relationship with the northern hemisphere Tinocladia (T. crassa, including a cryptic sister species T. pseudocrassa sp. nov., and T. sanrikuensis), whereas southern hemisphere Tinocladia (T. australis, T. falklandica, T. novae-zelandiae, and a cryptic species from New Zealand) nested in the Eudesme clade. Morphologically, Tinocladia species have been distinguished from Eudesme by their denser medullary filaments and more extensive subcortical layer, but our molecular phylogenetic analyses suggest that these features do not correlate with genetic differences. The cox3 sequence divergence between northern hemisphere Tinocladia and the lineage that includes Eudesme and southern hemisphere Tinocladia was comparable to or smaller than those within selected ectocarpalean genera. We therefore propose to merge Tinocladia with Eudesme and resurrect Eudesme crassa (Suringar) Okamura for T. crassa. Although the two independent lineages of T. crassa do not show marked morphological differences, they are genetically isolated even in sympatric populations. We therefore propose to treat them as independent species. In this paper we neotypify Tinocladia crassa (=Eudesme crassa), describe E. pseudocrassa sp. nov., and determine that the Californian population of E. crassa is an introduction from Northeast Asia. HIGHLIGHTS •A taxonomic revision of Eudesme and Tinocladia, based on genetic and morpho-anatomy, provides evidence to merge Tinocladia with Eudesme. •The finding of cryptic species in New Zealand highlights the need for further taxonomic studies in this region. •The genetic data have revealed the occurrence of a cryptic species within T. crassa in Japan.
{"title":"Taxonomic revision of Tinocladia (Ectocarpales s.l., Phaeophyceae): merger of Tinocladia with Eudesme and description of E. pseudocrassa sp. nov","authors":"H. Kawai, Kazusa Takeuchi, T. Hanyuda, J. Brodie, Robert J. Mrowicki, K. Miller, W. Nelson","doi":"10.1080/09670262.2023.2183265","DOIUrl":"https://doi.org/10.1080/09670262.2023.2183265","url":null,"abstract":"ABSTRACT A molecular phylogeny of Tinocladia and Eudesme based on specimens covering a large proportion of the known species was done using mitochondrial cox1 and cox3, chloroplast atpB, psaA, psbA and rbcL genes and 5.8S rDNA and its ITS2 region sequences. The phylogeny revealed a close phylogenetic relationship between the two genera and the occurrence of a cryptic species within the generitype T. crassa. Eudesme species (E. borealis, E. shandongensis and the generitype E. virescens) showed a sister relationship with the northern hemisphere Tinocladia (T. crassa, including a cryptic sister species T. pseudocrassa sp. nov., and T. sanrikuensis), whereas southern hemisphere Tinocladia (T. australis, T. falklandica, T. novae-zelandiae, and a cryptic species from New Zealand) nested in the Eudesme clade. Morphologically, Tinocladia species have been distinguished from Eudesme by their denser medullary filaments and more extensive subcortical layer, but our molecular phylogenetic analyses suggest that these features do not correlate with genetic differences. The cox3 sequence divergence between northern hemisphere Tinocladia and the lineage that includes Eudesme and southern hemisphere Tinocladia was comparable to or smaller than those within selected ectocarpalean genera. We therefore propose to merge Tinocladia with Eudesme and resurrect Eudesme crassa (Suringar) Okamura for T. crassa. Although the two independent lineages of T. crassa do not show marked morphological differences, they are genetically isolated even in sympatric populations. We therefore propose to treat them as independent species. In this paper we neotypify Tinocladia crassa (=Eudesme crassa), describe E. pseudocrassa sp. nov., and determine that the Californian population of E. crassa is an introduction from Northeast Asia. HIGHLIGHTS •A taxonomic revision of Eudesme and Tinocladia, based on genetic and morpho-anatomy, provides evidence to merge Tinocladia with Eudesme. •The finding of cryptic species in New Zealand highlights the need for further taxonomic studies in this region. •The genetic data have revealed the occurrence of a cryptic species within T. crassa in Japan.","PeriodicalId":12032,"journal":{"name":"European Journal of Phycology","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46247463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-22DOI: 10.1080/09670262.2023.2169767
A. Skriptsova, S. Shibneva, A. Semenchenko
ABSTRACT Traditional morphology-based investigations of the red algal genera Devaleraea and Palmaria (Palmariaceae, Rhodophyta) fail to provide accurate accounts of diversity and distribution for species from the Russian coast of the north-western Pacific. Consequently, there is much disagreement and taxonomic uncertainty regarding several species. To resolve these issues we conducted a molecular-assisted investigation that included a DNA barcode survey (COI-5’) and multilocus (COI-5’, cob, psaA, ITS) phylogenetic analyses. Our analyses indicate that diversity was previously underestimated for the Devaleraea/Palmaria complex. We describe three additional species of Devaleraea: D. sakhalinensis sp. nov., D. kussakinii sp. nov. and D. urupiana sp. nov. We consider D. titlyanoviorum to be an alga with abundant proliferations from the margins, branching to several orders, that is known only from Kunashir Island. Algae from Sakhalin Island and the mainland coast of the Sea of Japan previously identified as D. titlyanoviorum are described here as D. sakhalinensis. We confirmed that the genus Palmaria is not monotypic. It includes at least two species: P. palmata in the North Atlantic and P. moniliformis in the north-western Pacific. We expand the known ranges of D. callophylloides, D. mollis and P. hecatensis in the north-western Pacific southwards and find that D. stenogona is confined to the northern part of the Sea of Japan. The distribution patterns of species of the genera Devaleraea and Palmaria are discussed in relation to the oceanography of the north-western Pacific. HIGHLIGHTS Three new species of the genus Devaleraea are proposed. The genus Palmaria is not monotypic and includes at least two species, P. moniliformis and P. palmata.
{"title":"Morphological and molecular investigations shed light on diversity and distribution of Palmariaceae in the north-western Pacific","authors":"A. Skriptsova, S. Shibneva, A. Semenchenko","doi":"10.1080/09670262.2023.2169767","DOIUrl":"https://doi.org/10.1080/09670262.2023.2169767","url":null,"abstract":"ABSTRACT Traditional morphology-based investigations of the red algal genera Devaleraea and Palmaria (Palmariaceae, Rhodophyta) fail to provide accurate accounts of diversity and distribution for species from the Russian coast of the north-western Pacific. Consequently, there is much disagreement and taxonomic uncertainty regarding several species. To resolve these issues we conducted a molecular-assisted investigation that included a DNA barcode survey (COI-5’) and multilocus (COI-5’, cob, psaA, ITS) phylogenetic analyses. Our analyses indicate that diversity was previously underestimated for the Devaleraea/Palmaria complex. We describe three additional species of Devaleraea: D. sakhalinensis sp. nov., D. kussakinii sp. nov. and D. urupiana sp. nov. We consider D. titlyanoviorum to be an alga with abundant proliferations from the margins, branching to several orders, that is known only from Kunashir Island. Algae from Sakhalin Island and the mainland coast of the Sea of Japan previously identified as D. titlyanoviorum are described here as D. sakhalinensis. We confirmed that the genus Palmaria is not monotypic. It includes at least two species: P. palmata in the North Atlantic and P. moniliformis in the north-western Pacific. We expand the known ranges of D. callophylloides, D. mollis and P. hecatensis in the north-western Pacific southwards and find that D. stenogona is confined to the northern part of the Sea of Japan. The distribution patterns of species of the genera Devaleraea and Palmaria are discussed in relation to the oceanography of the north-western Pacific. HIGHLIGHTS Three new species of the genus Devaleraea are proposed. The genus Palmaria is not monotypic and includes at least two species, P. moniliformis and P. palmata.","PeriodicalId":12032,"journal":{"name":"European Journal of Phycology","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42974793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-03DOI: 10.1080/09670262.2023.2169768
Valter Loureiro de Araújo, Márcio Ferreira dos Santos, Alessandra Selbach Schnadelbach, José Marcos de Castro Nunes, Taiara Aguiar Caires
ABSTRACT Brazil’s Atlantic Ocean coast is approximately 7500 km long, with several coastal and oceanic islands. The cyanoflora of this area is not commonly included in published studies, resulting in an underestimated diversity. Here, we isolated and analysed through a polyphasic approach three strains of marine benthic homocyted cyanobacteria from Brazilian coastal islands with two distinct climates: ALCB 132761 and ALCB 132774 are from the tropics, and ALCB 132760 from the subtropics. These strains presented differences in their cell morphometry and presence/absence of sheath, but were similar in apical cell shape, colour, and form of the trichome. In the 16S rRNA phylogeny, Maximum likelihood (ML) and Bayesian posterior probability (PP) analyses placed our strains in two robust clades. We propose that Microlinema tropicalium gen. et sp. nov. (ALCB 132774) is placed in the Leptolyngbyaceae, and Insularia amadoi gen. et sp. nov. (ALCB 132761) and Salileptolyngbya insularis sp. nov. (ALCB 132760) in Pseudanabaenaceae. The 16S-23S Internal Transcribed Spacer (ITS) was used to reconstruct Box B and D1-D1’ secondary structures, which were treated as autapomorphic characters. The new thin homocyted benthic cyanobacterial taxa described here from marine coastal islands of Brazil help to disentangle the Leptolyngbyaceae and Pseudanabaenaceae. HIGHLIGHTS •Polyphasic description of two new Brazilian genera Insularia and Microlinema. •Expansion of Salileptolyngbya: recognition of one species for the Atlantic Ocean. •Elucidation of benthic genera in the Leptolyngbyaceae and Pseudanabaenaceae.
{"title":"New genera of thin homocyted cyanobacteria from Brazilian tropical and subtropical marine islands","authors":"Valter Loureiro de Araújo, Márcio Ferreira dos Santos, Alessandra Selbach Schnadelbach, José Marcos de Castro Nunes, Taiara Aguiar Caires","doi":"10.1080/09670262.2023.2169768","DOIUrl":"https://doi.org/10.1080/09670262.2023.2169768","url":null,"abstract":"ABSTRACT Brazil’s Atlantic Ocean coast is approximately 7500 km long, with several coastal and oceanic islands. The cyanoflora of this area is not commonly included in published studies, resulting in an underestimated diversity. Here, we isolated and analysed through a polyphasic approach three strains of marine benthic homocyted cyanobacteria from Brazilian coastal islands with two distinct climates: ALCB 132761 and ALCB 132774 are from the tropics, and ALCB 132760 from the subtropics. These strains presented differences in their cell morphometry and presence/absence of sheath, but were similar in apical cell shape, colour, and form of the trichome. In the 16S rRNA phylogeny, Maximum likelihood (ML) and Bayesian posterior probability (PP) analyses placed our strains in two robust clades. We propose that Microlinema tropicalium gen. et sp. nov. (ALCB 132774) is placed in the Leptolyngbyaceae, and Insularia amadoi gen. et sp. nov. (ALCB 132761) and Salileptolyngbya insularis sp. nov. (ALCB 132760) in Pseudanabaenaceae. The 16S-23S Internal Transcribed Spacer (ITS) was used to reconstruct Box B and D1-D1’ secondary structures, which were treated as autapomorphic characters. The new thin homocyted benthic cyanobacterial taxa described here from marine coastal islands of Brazil help to disentangle the Leptolyngbyaceae and Pseudanabaenaceae. HIGHLIGHTS •Polyphasic description of two new Brazilian genera Insularia and Microlinema. •Expansion of Salileptolyngbya: recognition of one species for the Atlantic Ocean. •Elucidation of benthic genera in the Leptolyngbyaceae and Pseudanabaenaceae.","PeriodicalId":12032,"journal":{"name":"European Journal of Phycology","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44683861","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-24DOI: 10.1080/09670262.2023.2164907
Laura Lagourgue, F. Rousseau, M. Zubia, C. Payri
ABSTRACT Avrainvillea is a green macroalgal genus of the family Dichotomosiphonaceae (order Bryopsidales). Many species have been morphologically described, but few studies have addressed the genetic diversity of this genus. Based on a rich collection of specimens from the tropical Western Atlantic, Indian and Pacific Oceans, we aimed to (1) reassess Avrainvillea species diversity through species delimitation analyses, (2) update their distribution ranges, (3) reconstruct the species phylogenetic relationships, based on a concatenated multilocus matrix (tufA, rbcL and 18S rDNA) and (4) revise their taxonomy and describe new species where necessary. Our species delimitation approach highlighted 23 secondary species hypotheses in our collection, including nine known and currently accepted species, four species complexes (A. amadelpha, A. lacerata, A. erecta-obscura and A. mazei-nigricans), and eight new species for which we provide descriptions: A. laciniata (Papua New Guinea), A. minima and A. pyrochroma (Madagascar), A. mollis and A. kanakiensis (New Caledonia), A. pavonina (Fiji), A. spongiosa (Pacific) and A. corticata (Indo-Pacific). We also propose the resurrection of A. gracillima Børgesen, the reinstatement of Avrainvillea lacerata var. robustior A.Gepp & E.S.Gepp, and the synonymy of A. rotumensis A.D.R.N’Yeurt, D.S.Littler & Littler with A. pacifica A.Gepp & E.S.Gepp. We complemented the taxonomic work by providing a contemporary dichotomous key for morphological identification of all extant species. Our multilocus phylogeny included 25 species of Dichotomosiphonaceae and recovered Avrainvillea as a polyphyletic group, divided into three distinct clades, with Cladocephalus luteofuscus positioned within the group. The species determined using the species delimitation approach were all monophyletic and 19 of them were highly supported. For the first time, this study also provided genetic sequences for A. asarifolia, A. clavatiramea, A. digitata, A. elliottii, A. fulva, A. gracillima, A. geppiorum, A. pacifica and A. obscura. HIGHLIGHTS • Avrainvillea is not monophyletic. • Reassessment of Avrainvillea species diversity delimited 23 secondary species hypotheses. • Eight new species of Avrainvillea were discovered in the Indo-Pacific.
{"title":"Diversity of the genus Avrainvillea (Dichotomosiphonaceae, Chlorophyta): new insights and eight new species","authors":"Laura Lagourgue, F. Rousseau, M. Zubia, C. Payri","doi":"10.1080/09670262.2023.2164907","DOIUrl":"https://doi.org/10.1080/09670262.2023.2164907","url":null,"abstract":"ABSTRACT Avrainvillea is a green macroalgal genus of the family Dichotomosiphonaceae (order Bryopsidales). Many species have been morphologically described, but few studies have addressed the genetic diversity of this genus. Based on a rich collection of specimens from the tropical Western Atlantic, Indian and Pacific Oceans, we aimed to (1) reassess Avrainvillea species diversity through species delimitation analyses, (2) update their distribution ranges, (3) reconstruct the species phylogenetic relationships, based on a concatenated multilocus matrix (tufA, rbcL and 18S rDNA) and (4) revise their taxonomy and describe new species where necessary. Our species delimitation approach highlighted 23 secondary species hypotheses in our collection, including nine known and currently accepted species, four species complexes (A. amadelpha, A. lacerata, A. erecta-obscura and A. mazei-nigricans), and eight new species for which we provide descriptions: A. laciniata (Papua New Guinea), A. minima and A. pyrochroma (Madagascar), A. mollis and A. kanakiensis (New Caledonia), A. pavonina (Fiji), A. spongiosa (Pacific) and A. corticata (Indo-Pacific). We also propose the resurrection of A. gracillima Børgesen, the reinstatement of Avrainvillea lacerata var. robustior A.Gepp & E.S.Gepp, and the synonymy of A. rotumensis A.D.R.N’Yeurt, D.S.Littler & Littler with A. pacifica A.Gepp & E.S.Gepp. We complemented the taxonomic work by providing a contemporary dichotomous key for morphological identification of all extant species. Our multilocus phylogeny included 25 species of Dichotomosiphonaceae and recovered Avrainvillea as a polyphyletic group, divided into three distinct clades, with Cladocephalus luteofuscus positioned within the group. The species determined using the species delimitation approach were all monophyletic and 19 of them were highly supported. For the first time, this study also provided genetic sequences for A. asarifolia, A. clavatiramea, A. digitata, A. elliottii, A. fulva, A. gracillima, A. geppiorum, A. pacifica and A. obscura. HIGHLIGHTS • Avrainvillea is not monophyletic. • Reassessment of Avrainvillea species diversity delimited 23 secondary species hypotheses. • Eight new species of Avrainvillea were discovered in the Indo-Pacific.","PeriodicalId":12032,"journal":{"name":"European Journal of Phycology","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43399447","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-21DOI: 10.1080/09670262.2023.2165711
C. Gueidan, Oliver L. Mead, Hadi Nazem-Bokaee, Sarah Mathews
ABSTRACT Although genome sequences of lichenized fungi are increasingly becoming available, genome sequences of microalgae involved in the lichen symbiosis are still scarce. For lichenized eukaryotic algae, genome sequencing has focused mostly on Trebouxia and Asterochloris, with little genomic data available for Stichococcus-like algae, such as Diplosphaera. The genus Diplosphaera is a common component of biological soil crusts, and often occurs associated with lichens of the family Verrucariaceae. It is characterized by cylindrical to spherical cells containing a plate-like chloroplast, and more specifically by a vegetative cell division that leads to the formation of typical two- to four-celled clusters. Here, we present a draft genome sequence for the algal partner of an Australian lichen specimen of Endocarpon pusillum. The genome was sequenced with Pac Bio long read and Illumina short read technologies, and transcriptome data were generated to inform the structural annotations. This algal strain is here identified as Diplosphaera chodatii based on nuSSU and ITS data. Compared with closely related lichenized and non-lichenized algae, the genome of D. chodatii stands out for its large size (85.6 Mb) and gene content (21,261 protein-encoding regions), as well as its high rate of duplicated genes (60% of the BUSCO genes are duplicated). These results suggest that whole genome duplication or large-scale segmental duplications may have occurred in the evolutionary history of this algal species. HIGHLIGHTS Little genome data are available for lichenized algae. We generated the first genome for a lichenized Diplosphaera chodatii. Results suggest a possible whole genome duplication in this species.
{"title":"First draft of an annotated genome for a lichenised strain of the green alga Diplosphaera chodatii (Prasiolales, Trebouxiophyceae)","authors":"C. Gueidan, Oliver L. Mead, Hadi Nazem-Bokaee, Sarah Mathews","doi":"10.1080/09670262.2023.2165711","DOIUrl":"https://doi.org/10.1080/09670262.2023.2165711","url":null,"abstract":"ABSTRACT Although genome sequences of lichenized fungi are increasingly becoming available, genome sequences of microalgae involved in the lichen symbiosis are still scarce. For lichenized eukaryotic algae, genome sequencing has focused mostly on Trebouxia and Asterochloris, with little genomic data available for Stichococcus-like algae, such as Diplosphaera. The genus Diplosphaera is a common component of biological soil crusts, and often occurs associated with lichens of the family Verrucariaceae. It is characterized by cylindrical to spherical cells containing a plate-like chloroplast, and more specifically by a vegetative cell division that leads to the formation of typical two- to four-celled clusters. Here, we present a draft genome sequence for the algal partner of an Australian lichen specimen of Endocarpon pusillum. The genome was sequenced with Pac Bio long read and Illumina short read technologies, and transcriptome data were generated to inform the structural annotations. This algal strain is here identified as Diplosphaera chodatii based on nuSSU and ITS data. Compared with closely related lichenized and non-lichenized algae, the genome of D. chodatii stands out for its large size (85.6 Mb) and gene content (21,261 protein-encoding regions), as well as its high rate of duplicated genes (60% of the BUSCO genes are duplicated). These results suggest that whole genome duplication or large-scale segmental duplications may have occurred in the evolutionary history of this algal species. HIGHLIGHTS Little genome data are available for lichenized algae. We generated the first genome for a lichenized Diplosphaera chodatii. Results suggest a possible whole genome duplication in this species.","PeriodicalId":12032,"journal":{"name":"European Journal of Phycology","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44137924","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-02DOI: 10.1080/09670262.2022.2068075
D. Khan-Bureau, S. Blanco, E. Morales, L. Ector, Michael S. Beauchene, L. Lewis
ABSTRACT Two morphologically similar populations of Didymosphenia were reported from the West Branch of the Farmington River, Connecticut, USA in 2014 and 2016. We described one of them as a new species, D. hullii. The other was observed subsequently in late 2016 and resembled D. geminata, but given the worldwide nuisance characteristic of this species, the identification required confirmation. In this work we used geometric morphometrics analysis to test for quantitative distinctions between the two Connecticut populations, along with two morphologically similar taxa from the literature, D. laticollis and D. pumila. We successfully separated the four entities and confirmed the identity of the second blooming diatom in the Farmington River, Connecticut, as D. geminata, which is the first confirmed report of this species for the state. We conclude that geometric morphometrics, in combination with features viewed with scanning electron microscopy and light microscopy, enhances the ability to distinguish among these morphologically similar species of Didymosphenia. We summarize these findings and pinpoint morphological distinctions that can be used to separate the taxa during routine light microscopy analyses. HIGHLIGHTS Geometric morphometrics was used to differentiate four Didymosphenia taxa. Morphological comparisons of D. hullii and D. geminata are shown. Didymosphenia geminata was recently reported in Connecticut, USA.
{"title":"Using geometric morphometrics to disentangle Didymosphenia hullii and D. geminata (Bacillariophyceae) from Connecticut, USA, and two congeneric relatives","authors":"D. Khan-Bureau, S. Blanco, E. Morales, L. Ector, Michael S. Beauchene, L. Lewis","doi":"10.1080/09670262.2022.2068075","DOIUrl":"https://doi.org/10.1080/09670262.2022.2068075","url":null,"abstract":"ABSTRACT Two morphologically similar populations of Didymosphenia were reported from the West Branch of the Farmington River, Connecticut, USA in 2014 and 2016. We described one of them as a new species, D. hullii. The other was observed subsequently in late 2016 and resembled D. geminata, but given the worldwide nuisance characteristic of this species, the identification required confirmation. In this work we used geometric morphometrics analysis to test for quantitative distinctions between the two Connecticut populations, along with two morphologically similar taxa from the literature, D. laticollis and D. pumila. We successfully separated the four entities and confirmed the identity of the second blooming diatom in the Farmington River, Connecticut, as D. geminata, which is the first confirmed report of this species for the state. We conclude that geometric morphometrics, in combination with features viewed with scanning electron microscopy and light microscopy, enhances the ability to distinguish among these morphologically similar species of Didymosphenia. We summarize these findings and pinpoint morphological distinctions that can be used to separate the taxa during routine light microscopy analyses. HIGHLIGHTS Geometric morphometrics was used to differentiate four Didymosphenia taxa. Morphological comparisons of D. hullii and D. geminata are shown. Didymosphenia geminata was recently reported in Connecticut, USA.","PeriodicalId":12032,"journal":{"name":"European Journal of Phycology","volume":"58 1","pages":"99 - 109"},"PeriodicalIF":2.4,"publicationDate":"2023-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45559040","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-20DOI: 10.1080/09670262.2022.2150894
S. Beer
ABSTRACT Ulva is an opportunistically growing green macroalgal genus, the worldwide distribution of which can partly be explained by its ability to employ two alternative modes of photosynthetic inorganic carbon acquisition. In temperate areas, the less efficient (in terms of inorganic carbon utilization), externally acting, carbonic anhydrase-catalysed HCO3 – to CO2 conversion mechanism prevails. However, when growing in warmer and higher irradiance regions, or if transferred to high-pH seawater, Ulva features a highly efficient HCO3 − uptake system unique among macroalgae. In addition, the light reactions acclimate effectively to various irradiances, including full sunlight in the intertidal. The following topics are discussed in this review, often in a historical perspective, in the context of two questions: (1) Is there a need for a CO2 concentrating mechanism? (Yes!) and (2) if so, is Ulva a C4 alga? (No!). How Ulva utilizes external HCO3 − for its photosynthetic needs is discussed, considering the ability of Ulva to increase pH values to >10 in enclosed areas such as rockpools, and its ecological consequences. The ability of intertidal Ulva to photosynthesize when emergent is addressed, and mechanisms protecting the light reactions from high irradiances are reviewed. Finally, Ulva is viewed in the context of future environments of increased CO2 and ocean acidification. HIGHLIGHTS Photosystems II and I of Ulva are well protected from high irradiances. Ulva is unique among macroalgae in using a plasma membrane HCO3 – transport system. Ulva’s efficient photosynthetic traits allow it to thrive worldwide.
{"title":"Photosynthetic traits of the ubiquitous and prolific macroalga Ulva (Chlorophyta): a review","authors":"S. Beer","doi":"10.1080/09670262.2022.2150894","DOIUrl":"https://doi.org/10.1080/09670262.2022.2150894","url":null,"abstract":"ABSTRACT Ulva is an opportunistically growing green macroalgal genus, the worldwide distribution of which can partly be explained by its ability to employ two alternative modes of photosynthetic inorganic carbon acquisition. In temperate areas, the less efficient (in terms of inorganic carbon utilization), externally acting, carbonic anhydrase-catalysed HCO3 – to CO2 conversion mechanism prevails. However, when growing in warmer and higher irradiance regions, or if transferred to high-pH seawater, Ulva features a highly efficient HCO3 − uptake system unique among macroalgae. In addition, the light reactions acclimate effectively to various irradiances, including full sunlight in the intertidal. The following topics are discussed in this review, often in a historical perspective, in the context of two questions: (1) Is there a need for a CO2 concentrating mechanism? (Yes!) and (2) if so, is Ulva a C4 alga? (No!). How Ulva utilizes external HCO3 − for its photosynthetic needs is discussed, considering the ability of Ulva to increase pH values to >10 in enclosed areas such as rockpools, and its ecological consequences. The ability of intertidal Ulva to photosynthesize when emergent is addressed, and mechanisms protecting the light reactions from high irradiances are reviewed. Finally, Ulva is viewed in the context of future environments of increased CO2 and ocean acidification. HIGHLIGHTS Photosystems II and I of Ulva are well protected from high irradiances. Ulva is unique among macroalgae in using a plasma membrane HCO3 – transport system. Ulva’s efficient photosynthetic traits allow it to thrive worldwide.","PeriodicalId":12032,"journal":{"name":"European Journal of Phycology","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2022-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44873413","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-11-24DOI: 10.1080/09670262.2022.2136405
J. García-Plazaola, M. I. Arzac, Laura Brazales, Javier Fernández, J. M. Laza, J. Vilas, M. López-Pozo, A. Perera-Castro, B. Fernández-Marín
ABSTRACT Antarctic macroalgal communities of the upper intertidal zone are particularly poor compared with other coastal regions. Exposure to desiccation and freezing combined with the abrasive effect of ice threatens the life of sessile organisms. One of the few species able to colonize this environment is the rhodophyte Pyropia endiviifolia. It belongs to the Bangiales, one of the oldest extant clades of photosynthetic eukaryotes, which has occurred for more than one billion years with basically the same morphological structure. Considering that the extent of Antarctic glaciation is a geologically recent event, we hypothesized that pre-adaptations to desiccation in bangiophytes may have contributed to the success of P. endiviifolia in Antarctica. To test this, we compared its photosynthetic performance and tolerance to desiccation and freezing with those from a related intertidal species, the temperate Atlantic species Porphyra linearis. As evidenced by gas exchange and chlorophyll fluorescence, P. endiviifolia is more adapted to high irradiances than P. linearis. The former species was also more desiccation-tolerant, and showed a higher glass transition temperature. Both species did not differ in chlorophyll content per dry weight, and tolerance to −20°C, even though the ice-nucleation temperature was much higher in P. endiviifolia. Membrane integrity may depend on fatty acid composition in P. endiviifolia, while on enhanced tocopherol in P. linearis. Overall, both species show different strategies to deal with freezing temperatures: supercooling in P. linearis vs. freezing-tolerance in P. endiviifolia. This matches with the probability of being subjected to sub-zero temperatures in their natural environments (lower in the case of P. linearis). Surprisingly, the higher risk of dehydration in the natural habitat of P. linearis is not matched by a higher desiccation tolerance. This observation does not support the initial hypothesis of the study but suggests the opposite: the acclimation to a cold environment results in higher desiccation tolerance. HIGHLIGHTS ● Porphyra linearis and Pyropia endiviifolia are remarkably tolerant to desiccation and freezing.● Antarctic P. endiviifolia is remarkably tolerant to desiccation and freezing.● Mechanisms of freezing tolerance could induce a higher tolerance to desiccation.
{"title":"Freezing and desiccation tolerance in the Antarctic bangiophyte Pyropia endiviifolia (Rhodophyta): a chicken and egg problem?","authors":"J. García-Plazaola, M. I. Arzac, Laura Brazales, Javier Fernández, J. M. Laza, J. Vilas, M. López-Pozo, A. Perera-Castro, B. Fernández-Marín","doi":"10.1080/09670262.2022.2136405","DOIUrl":"https://doi.org/10.1080/09670262.2022.2136405","url":null,"abstract":"ABSTRACT Antarctic macroalgal communities of the upper intertidal zone are particularly poor compared with other coastal regions. Exposure to desiccation and freezing combined with the abrasive effect of ice threatens the life of sessile organisms. One of the few species able to colonize this environment is the rhodophyte Pyropia endiviifolia. It belongs to the Bangiales, one of the oldest extant clades of photosynthetic eukaryotes, which has occurred for more than one billion years with basically the same morphological structure. Considering that the extent of Antarctic glaciation is a geologically recent event, we hypothesized that pre-adaptations to desiccation in bangiophytes may have contributed to the success of P. endiviifolia in Antarctica. To test this, we compared its photosynthetic performance and tolerance to desiccation and freezing with those from a related intertidal species, the temperate Atlantic species Porphyra linearis. As evidenced by gas exchange and chlorophyll fluorescence, P. endiviifolia is more adapted to high irradiances than P. linearis. The former species was also more desiccation-tolerant, and showed a higher glass transition temperature. Both species did not differ in chlorophyll content per dry weight, and tolerance to −20°C, even though the ice-nucleation temperature was much higher in P. endiviifolia. Membrane integrity may depend on fatty acid composition in P. endiviifolia, while on enhanced tocopherol in P. linearis. Overall, both species show different strategies to deal with freezing temperatures: supercooling in P. linearis vs. freezing-tolerance in P. endiviifolia. This matches with the probability of being subjected to sub-zero temperatures in their natural environments (lower in the case of P. linearis). Surprisingly, the higher risk of dehydration in the natural habitat of P. linearis is not matched by a higher desiccation tolerance. This observation does not support the initial hypothesis of the study but suggests the opposite: the acclimation to a cold environment results in higher desiccation tolerance. HIGHLIGHTS ● Porphyra linearis and Pyropia endiviifolia are remarkably tolerant to desiccation and freezing.● Antarctic P. endiviifolia is remarkably tolerant to desiccation and freezing.● Mechanisms of freezing tolerance could induce a higher tolerance to desiccation.","PeriodicalId":12032,"journal":{"name":"European Journal of Phycology","volume":"1 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2022-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42998795","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-31DOI: 10.1080/09670262.2022.2126894
J. Neiva, R. Bermejo, A. Medrano, P. Capdevila, David Milla-Figueras, Pedro A. Afonso, E. Ballesteros, B. Sabour, D. Serio, Eduardo Nóbrega, J. Soares, J. Valdazo, F. Tuya, M. Mulas, Á. Israel, S. S. Sadogurska, M. Guiry, G. Pearson, E. Serrão
ABSTRACT Cystoseira sensu lato (s.l.) – encompassing the genera Cystoseira sensu stricto (s.s.), Ericaria and Gongolaria – is a diverse group of forest-forming brown macroalgae endemic to the warm-temperate North-east Atlantic. These algae have immense biogeographic and ecological significance and have been experiencing recent regional declines. Most Cystoseira s.l. display important morphological plasticity and can be confused with similar species. Therefore, species boundaries, geographic ranges and phylogenetic affinities remain imprecise for most. In the face of persistent taxonomic difficulties, several authors underlined the necessity for new molecular-based approaches, but studies so far lacked representativity, resolution and standardization. To fill in these gaps, in this study we sequenced a comprehensive collection of Cystoseira s.l. spanning its entire North-east Atlantic range for a ~1200 bp cox1 barcode, and sequenced selected individuals representing major genetic entities for a few additional plastid markers. Phylogeographic, phylogenetic and species delimitation methods revealed 27 Molecular Operational Taxonomic Units, including unaccounted cryptic diversity, and elucidated with unprecedented resolution species compositions and phylogenetic relationships within each genus. Some entities within the lineages Cystoseira compressa/humilis, Ericaria brachycarpa/crinita, E. selaginoides and tophulose Gongolaria, as well as among free-living algae, conflicted with a priori taxonomic assignments, and required the redefinition, reinstatement and recognition of new taxa. For some, diagnostic mutations and biogeography were more useful for species identifications than morphological characters or conventional barcoding gaps. A few species showed narrow geographic ranges and others were the sole representatives of their respective lineages. Several sister-species showed Atlantic vs Mediterranean complementary ranges. Phylogenetic signal of cox1 was nevertheless insufficient to confidently determine patterns of lineage splitting in several lineages and species complexes and did not improve significantly with additional plastid markers. We discuss novel systematics and biogeography insights considering the advantages and shortcomings of the barcoding approach employed, and how this comprehensive baseline study can be expanded to address multiple questions still left unanswered. HIGHLIGHTS Identification of major genetic entities of Cystoseira s.s., Ericaria and Gongolaria. A comprehensive reference cox1 barcode library for Cystoseira s.l. Updated systematics and biogeography of Cystoseira s.l.
{"title":"DNA barcoding reveals cryptic diversity, taxonomic conflicts and novel biogeographical insights in Cystoseira s.l. (Phaeophyceae)","authors":"J. Neiva, R. Bermejo, A. Medrano, P. Capdevila, David Milla-Figueras, Pedro A. Afonso, E. Ballesteros, B. Sabour, D. Serio, Eduardo Nóbrega, J. Soares, J. Valdazo, F. Tuya, M. Mulas, Á. Israel, S. S. Sadogurska, M. Guiry, G. Pearson, E. Serrão","doi":"10.1080/09670262.2022.2126894","DOIUrl":"https://doi.org/10.1080/09670262.2022.2126894","url":null,"abstract":"ABSTRACT Cystoseira sensu lato (s.l.) – encompassing the genera Cystoseira sensu stricto (s.s.), Ericaria and Gongolaria – is a diverse group of forest-forming brown macroalgae endemic to the warm-temperate North-east Atlantic. These algae have immense biogeographic and ecological significance and have been experiencing recent regional declines. Most Cystoseira s.l. display important morphological plasticity and can be confused with similar species. Therefore, species boundaries, geographic ranges and phylogenetic affinities remain imprecise for most. In the face of persistent taxonomic difficulties, several authors underlined the necessity for new molecular-based approaches, but studies so far lacked representativity, resolution and standardization. To fill in these gaps, in this study we sequenced a comprehensive collection of Cystoseira s.l. spanning its entire North-east Atlantic range for a ~1200 bp cox1 barcode, and sequenced selected individuals representing major genetic entities for a few additional plastid markers. Phylogeographic, phylogenetic and species delimitation methods revealed 27 Molecular Operational Taxonomic Units, including unaccounted cryptic diversity, and elucidated with unprecedented resolution species compositions and phylogenetic relationships within each genus. Some entities within the lineages Cystoseira compressa/humilis, Ericaria brachycarpa/crinita, E. selaginoides and tophulose Gongolaria, as well as among free-living algae, conflicted with a priori taxonomic assignments, and required the redefinition, reinstatement and recognition of new taxa. For some, diagnostic mutations and biogeography were more useful for species identifications than morphological characters or conventional barcoding gaps. A few species showed narrow geographic ranges and others were the sole representatives of their respective lineages. Several sister-species showed Atlantic vs Mediterranean complementary ranges. Phylogenetic signal of cox1 was nevertheless insufficient to confidently determine patterns of lineage splitting in several lineages and species complexes and did not improve significantly with additional plastid markers. We discuss novel systematics and biogeography insights considering the advantages and shortcomings of the barcoding approach employed, and how this comprehensive baseline study can be expanded to address multiple questions still left unanswered. HIGHLIGHTS Identification of major genetic entities of Cystoseira s.s., Ericaria and Gongolaria. A comprehensive reference cox1 barcode library for Cystoseira s.l. Updated systematics and biogeography of Cystoseira s.l.","PeriodicalId":12032,"journal":{"name":"European Journal of Phycology","volume":"58 1","pages":"351 - 375"},"PeriodicalIF":2.4,"publicationDate":"2022-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49664485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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