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1.
J Phycol ; 2020 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-32196675

RESUMO

The cosmopolitan red algal genus Pyropia sensu lato is the most speciose of the bladed Bangiales genera. In a major revision of the Bangiales, Pyropia was resurrected from Porphyra, although there was evidence at the time that species of Pyropia could be separated into several genera. Subsequent global phylogenetic analyses continued to resolve species assigned to Pyropia into several major clades with strong support, and the latest biogeographic analyses indicated that species distribution was also a pointer to the underlying phylogeny of Pyropia sensu lato. Therefore, in the present study, we have redefined the genus Pyropia, resurrected Porphyrella, and proposed four new genera: Calidia, Neoporphyra, Neopyropia and Uedaea. Based on a molecular phylogenetic study of the bladed Bangiales of China, a species which did not match any known taxa, was resolved in the new genus Calidia. The species, Calidia pseudolobata sp. nov., is described based on both morphological and molecular data. Molecular sequence data for rbcL, 18S and COI-5P were amplified for fifteen samples in the present study. All the obtained rbcL sequences were identical to each other except for one (LYCN117) with one base pair difference. Two haplotypes of 18S (V9 region) were observed with one base pair difference (C/T30 ). All the obtained COI-5P sequences were identical. Morphological comparisons were conducted not only with species in Calidia, but also with generically uncertain species currently assigned to Porphyra.

2.
J Phycol ; 2019 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-31855278

RESUMO

North-Atlantic records of Schizymenia dubyi extend along the eastern shores of the North Atlantic from Morocco to southern Britain and Ireland, and the species is also recorded from Iceland. A study was undertaken to confirm the identity of the specimens from Iceland that were geographically separate from the main distribution of S. dubyi and in contrast to other species of the genus did not have gland cells. We analyzed rbcL and COI molecular sequence data from Icelandic specimens and compared the results with those for Schizymenia specimens available in GenBank. For both markers, Schizymenia was shown to be a monophyletic genus. The Icelandic specimens were clearly genetically distinct from S. dubyi and formed a well-supported clade with Schizymenia species from the Northern Pacific. Based on these results, we have described a new species, Schizymenia jonssonii, which can be distinguished by molecular phylogeny, its lack of gland cells and by being strictly intertidal. Crustose tetrasporophytes with identical COI and rbcL sequences were found at the same locations as foliose plants. Schizymenia apoda is reported for the first time in the UK, its identity confirmed by rbcL sequence data. In light of these findings, it is likely that by further molecular analysis of the genus Schizymenia in the north-eastern Atlantic and the Mediterranean, a higher diversity of Schizymenia spp. will be discovered in this region.

3.
Glob Chang Biol ; 25(3): 1032-1048, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30548757

RESUMO

The European Union (EU) has recently published its first list of invasive alien species (IAS) of EU concern to which current legislation must apply. The list comprises species known to pose great threats to biodiversity and needs to be maintained and updated. Horizon scanning is seen as critical to identify the most threatening potential IAS that do not yet occur in Europe to be subsequently risk assessed for future listing. Accordingly, we present a systematic consensus horizon scanning procedure to derive a ranked list of potential IAS likely to arrive, establish, spread and have an impact on biodiversity in the region over the next decade. The approach is unique in the continental scale examined, the breadth of taxonomic groups and environments considered, and the methods and data sources used. International experts were brought together to address five broad thematic groups of potential IAS. For each thematic group the experts first independently assembled lists of potential IAS not yet established in the EU but potentially threatening biodiversity if introduced. Experts were asked to score the species within their thematic group for their separate likelihoods of i) arrival, ii) establishment, iii) spread, and iv) magnitude of the potential negative impact on biodiversity within the EU. Experts then convened for a 2-day workshop applying consensus methods to compile a ranked list of potential IAS. From an initial working list of 329 species, a list of 66 species not yet established in the EU that were considered to be very high (8 species), high (40 species) or medium (18 species) risk species was derived. Here, we present these species highlighting the potential negative impacts and the most likely biogeographic regions to be affected by these potential IAS.


Assuntos
Biodiversidade , Ecossistema , Espécies Introduzidas/tendências , Animais , Conferências de Consenso como Assunto , Política Ambiental , União Europeia , Espécies Introduzidas/estatística & dados numéricos , Medição de Risco
4.
Mol Phylogenet Evol ; 120: 94-102, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29180103

RESUMO

A molecular taxonomic study was undertaken for the first time of the bladed Bangiales of the mainland coast of China (Northwest Pacific) based on sequence data of 201 plastid rbcL and 148 nuclear 18S sequences of historical and contemporary specimens. The results revealed that only one genus of bladed Bangiales, Pyropia, was present along Chinese coast. Species delimitation was determined using two empirical methods: the Automatic Barcode Gap Discovery (ABGD) and General Mixed Yule Coalescence (GMYC) coupled with detection of monophyly in tree reconstruction. At least fourteen species of Pyropia were recovered. Six species were confirmed that had been recorded previously based on morphology (Py. suborbiculata, Py. yezoensis, Py. haitanensis, Py. katadae, Py. tenera and Py. acanthophora), three species were recorded from China for the first time (Py. kinositae, Py. pseudolinearis and Py. tanegashimensis), and five cryptic species that did not match any molecular sequences were also discovered. The phylogeny of the concatenated rbcL and 18S dataset resolved three singletons and four clades. Each clades has a strong trend towards occupying a biogeographic region, but they are not confined to them. A transoceanic and antitropical pattern of distribution was found for Pyropia at both the subgeneric and species level. This together with high biodiversity (ca. 30% of all known Pyropia species) indicates that the Northwest Pacific might act as a centre of origin for modern distribution of Pyropia since the early Cenozoic.


Assuntos
Biodiversidade , Filogenia , Filogeografia , Rodófitas/classificação , Sequência de Bases , Teorema de Bayes , China , Código de Barras de DNA Taxonômico , Especificidade da Espécie
5.
New Phytol ; 216(3): 670-681, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28857164

RESUMO

Contents 670 I. 671 II. 671 III. 676 IV. 678 678 References 678 SUMMARY: Biotic interactions underlie life's diversity and are the lynchpin to understanding its complexity and resilience within an ecological niche. Algal biologists have embraced this paradigm, and studies building on the explosive growth in omics and cell biology methods have facilitated the in-depth analysis of nonmodel organisms and communities from a variety of ecosystems. In turn, these advances have enabled a major revision of our understanding of the origin and evolution of photosynthesis in eukaryotes, bacterial-algal interactions, control of massive algal blooms in the ocean, and the maintenance and degradation of coral reefs. Here, we review some of the most exciting developments in the field of algal biotic interactions and identify challenges for scientists in the coming years. We foresee the development of an algal knowledgebase that integrates ecosystem-wide omics data and the development of molecular tools/resources to perform functional analyses of individuals in isolation and in populations. These assets will allow us to move beyond mechanistic studies of a single species towards understanding the interactions amongst algae and other organisms in both the laboratory and the field.


Assuntos
Antozoários/fisiologia , Evolução Biológica , Feófitas/fisiologia , Animais , Cromatóforos , Dinoflagelados/fisiologia , Eutrofização , Interações Hospedeiro-Patógeno , Fotossíntese , Phycodnaviridae/patogenicidade , Filogenia , Plastídeos , Simbiose
6.
Proc Natl Acad Sci U S A ; 114(31): E6361-E6370, 2017 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-28716924

RESUMO

Porphyra umbilicalis (laver) belongs to an ancient group of red algae (Bangiophyceae), is harvested for human food, and thrives in the harsh conditions of the upper intertidal zone. Here we present the 87.7-Mbp haploid Porphyra genome (65.8% G + C content, 13,125 gene loci) and elucidate traits that inform our understanding of the biology of red algae as one of the few multicellular eukaryotic lineages. Novel features of the Porphyra genome shared by other red algae relate to the cytoskeleton, calcium signaling, the cell cycle, and stress-tolerance mechanisms including photoprotection. Cytoskeletal motor proteins in Porphyra are restricted to a small set of kinesins that appear to be the only universal cytoskeletal motors within the red algae. Dynein motors are absent, and most red algae, including Porphyra, lack myosin. This surprisingly minimal cytoskeleton offers a potential explanation for why red algal cells and multicellular structures are more limited in size than in most multicellular lineages. Additional discoveries further relating to the stress tolerance of bangiophytes include ancestral enzymes for sulfation of the hydrophilic galactan-rich cell wall, evidence for mannan synthesis that originated before the divergence of green and red algae, and a high capacity for nutrient uptake. Our analyses provide a comprehensive understanding of the red algae, which are both commercially important and have played a major role in the evolution of other algal groups through secondary endosymbioses.


Assuntos
Citoesqueleto/genética , Evolução Molecular , Genoma de Planta/genética , Porphyra/citologia , Porphyra/genética , Actinas/genética , Sinalização do Cálcio/genética , Ciclo Celular/genética , Parede Celular/genética , Parede Celular/metabolismo , Cromatina/genética , Cinesina/genética , Filogenia
7.
Trends Plant Sci ; 22(8): 726-738, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28610890

RESUMO

Algae are (mostly) photosynthetic eukaryotes that occupy multiple branches of the tree of life, and are vital for planet function and health. In this review, we highlight a transformative period in studies of the evolution and functioning of this extraordinary group of organisms and their potential for novel applications, wrought by high-throughput 'omic' and reverse genetic methods. We cover the origin and diversification of algal groups, explore advances in understanding the link between phenotype and genotype, consider algal sex determination, and review progress in understanding the roots of algal multicellularity. Experimental evolution studies to determine how algae evolve in changing environments are highlighted, as is their potential as production platforms for compounds of commercial interest, such as biofuel precursors, nutraceuticals, or therapeutics.


Assuntos
Fotossíntese , Estramenópilas/genética , Biodiversidade , Evolução Biológica , Biotecnologia , Ecologia , Transferência Genética Horizontal , Estramenópilas/fisiologia , Simbiose
8.
J Eukaryot Microbiol ; 64(3): 407-411, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28337822

RESUMO

Universal taxonomic frameworks have been critical tools to structure the fields of botany, zoology, mycology, and bacteriology as well as their large research communities. Animals, plants, and fungi have relatively solid, stable morpho-taxonomies built over the last three centuries, while bacteria have been classified for the last three decades under a coherent molecular taxonomic framework. By contrast, no such common language exists for microbial eukaryotes, even though environmental '-omics' surveys suggest that protists make up most of the organismal and genetic complexity of our planet's ecosystems! With the current deluge of eukaryotic meta-omics data, we urgently need to build up a universal eukaryotic taxonomy bridging the protist -omics age to the fragile, centuries-old body of classical knowledge that has effectively linked protist taxa to morphological, physiological, and ecological information. UniEuk is an open, inclusive, community-based and expert-driven international initiative to build a flexible, adaptive universal taxonomic framework for eukaryotes. It unites three complementary modules, EukRef, EukBank, and EukMap, which use phylogenetic markers, environmental metabarcoding surveys, and expert knowledge to inform the taxonomic framework. The UniEuk taxonomy is directly implemented in the European Nucleotide Archive at EMBL-EBI, ensuring its broad use and long-term preservation as a reference taxonomy for eukaryotes.


Assuntos
Classificação , Eucariotos/classificação , Animais , Bactérias/classificação , Biodiversidade , Bases de Dados de Ácidos Nucleicos , Ecossistema , Meio Ambiente , Eucariotos/citologia , Eucariotos/genética , Eucariotos/fisiologia , Células Eucarióticas , Fungos/classificação , Filogenia
9.
FEMS Microbiol Ecol ; 92(8)2016 08.
Artigo em Inglês | MEDLINE | ID: mdl-27222222

RESUMO

The living prokaryotic microbiome of the calcified geniculate (articulated) red alga, Corallina officinalis from the intertidal seashore is characterised for the first time based on the V6 hypervariable region of 16S rRNA. Results revealed an extraordinary diversity of bacteria associated with the microbiome. Thirty-five prokaryotic phyla were recovered, of which Proteobacteria, Cyanobacteria, Bacteroidetes, Actinobacteria, Planctomycetes, Acidobacteria, Verrucomicrobia, Firmicutes and Chloroflexi made up the core microbiome. Unclassified sequences made up 25% of sequences, suggesting insufficient sampling of the world's oceans/macroalgae. The greatest diversity in the microbiome was on the upper shore, followed by the lower shore then the middle shore, although the microbiome community composition did not vary between shore levels. The C. officinalis core microbiome was broadly similar in composition to those reported in the literature for crustose coralline algae (CCAs) and free-living rhodoliths. Differences in relative abundance of the phyla between the different types of calcified macroalgal species may relate to the intertidal versus subtidal habit of the taxa and functionality of the microbiome components. The results indicate that much work is needed to identify prokaryotic taxa, and to determine the nature of the relationship of the bacteria with the calcified host spatially, temporally and functionally.


Assuntos
Microbiota , Rodófitas/microbiologia , Actinobacteria/genética , Bactérias/genética , Bacteroidetes/genética , Chloroflexi/genética , Cianobactérias/genética , Proteobactérias/genética , RNA Ribossômico 16S/genética
10.
Mol Phylogenet Evol ; 94(Pt B): 814-826, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26484942

RESUMO

A molecular taxonomic study of the bladed Bangiales of the South Eastern Pacific (coast of Chile) was undertaken based on sequence data of the mitochondrial COI and chloroplast rbcL for 193 specimens collected from Arica (18°S) in the north to South Patagonia (53°S) in the south. The results revealed for the first time that four genera, Porphyra, Pyropia, Fuscifolium and Wildemania were present in the region. Species delimitation was determined based on a combination of a General Mixed Yule Coalescence model (GMYC) and Automatic Barcode Gap Discovery (ABGD) coupled with detection of monophyly in tree reconstruction. The overall incongruence between the species delimitation methods within each gene was 29%. The GMYC method led to over-splitting groups, whereas the ABGD method had a tendency to lump groups. Taking a conservative approach to the number of putative species, at least 18 were recognized and, with the exception of the recently described Pyropia orbicularis, all were new to the Chilean flora. Porphyra and Pyropia were the most diverse genera with eight 'species' each, whereas only a 'single' species each was found for Fuscifolium and Wildemania. There was also evidence of recently diverging groups: Wildemania sp. was distinct but very closely related to W. amplissima from the Northern Hemisphere and raises questions in relation to such disjunct distributions. Pyropia orbicularis was very closely related to two other species, making species delimitation very difficult but provides evidence of an incipient speciation. The difference between the 'species' discovered and those previously reported for the region is discussed in relation to the difficulty of distinguishing species based on morphological identification.


Assuntos
Rodófitas/classificação , Evolução Biológica , Chile , Código de Barras de DNA Taxonômico/métodos , Marcadores Genéticos , Especiação Genética , Variação Genética , Filogenia , Porphyra , Rodófitas/genética
11.
Sci Rep ; 5: 11645, 2015 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-26139470

RESUMO

The marine world is incredibly rich in brilliant and intense colours. Photonic structures are found in many different species and provide extremely complex optical responses that cannot be achieved solely by pigments. In this study we examine the cuticular structure of the red alga Chondrus crispus (Irish Moss) using anatomical and optical approaches. We experimentally measure the optical response of the multilayer structure in the cuticle. Using finite-difference time-domain modelling, we demonstrate conclusively for the first time that the dimensions and organisation of lamellae are responsible for the blue structural colouration on the surface of the fronds. Comparison of material along the apical-basal axis of the frond demonstrates that structural colour is confined to the tips of the thalli and show definitively that a lack of structural colour elsewhere corresponds with a reduction in the number of lamellae and the regularity of their ordering. Moreover, by studying the optical response for different hydration conditions, we demonstrate that the cuticular structure is highly porous and that the presence of water plays a critical role in its ability to act as a structural light reflector.


Assuntos
Chondrus/ultraestrutura , Chondrus/metabolismo , Dessecação , Microscopia Eletrônica de Transmissão , Pigmentação
12.
Ecol Evol ; 4(13): 2787-98, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25077027

RESUMO

Seaweed and seagrass communities in the northeast Atlantic have been profoundly impacted by humans, and the rate of change is accelerating rapidly due to runaway CO2 emissions and mounting pressures on coastlines associated with human population growth and increased consumption of finite resources. Here, we predict how rapid warming and acidification are likely to affect benthic flora and coastal ecosystems of the northeast Atlantic in this century, based on global evidence from the literature as interpreted by the collective knowledge of the authorship. We predict that warming will kill off kelp forests in the south and that ocean acidification will remove maerl habitat in the north. Seagrasses will proliferate, and associated epiphytes switch from calcified algae to diatoms and filamentous species. Invasive species will thrive in niches liberated by loss of native species and spread via exponential development of artificial marine structures. Combined impacts of seawater warming, ocean acidification, and increased storminess may replace structurally diverse seaweed canopies, with associated calcified and noncalcified flora, with simple habitats dominated by noncalcified, turf-forming seaweeds.

13.
J Phycol ; 50(5): 908-29, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26988645

RESUMO

The diversity of the bladed species of the red algal order Bangiales from the Iberian Mediterranean shores has been reassessed after a detailed study of this region. Prior to this study, 11 bladed species of Bangiales had been reported from Mediterranean waters: Porphyra atropurpurea, P. cordata, P. coriacea, P. dioica, P. linearis, P. purpurea, P. umbilicalis, Pyropia leucosticta, Pyropia koreana (as P. olivii), Py. elongata (as P. rosengurttii) and Py. suborbiculata. A combined analysis of the nuclear nSSU and the plastid rbcL genes together with detailed morphological studies has confirmed the presence of species within the genera Porphyra and Pyropia and also revealed a third, undescribed genus, Themis gen. nov. Porphyra linearis, Pyropia elongata and the introduced Pyropia koreana had been previously listed for the Mediterranean and were recorded in this study. An additional four species, including the introduced Pyropia suborbiculata and three new species: Pyropia parva sp. nov., Themis ballesterosii sp. nov., and Themis iberica sp. nov. were also observed. Hence, most of the Porphyra species traditionally reported along these shores were not reported in this survey. This new floristic Bangiales composition confirms the importance of the Mediterranean basin as a hotspot for biodiversity, possible endemics of ancient origin and high proportion of introductions. Our data also continue to confirm the extent of Bangiales diversity at regional and worldwide levels.

14.
J Phycol ; 48(4): 1020-7, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27009012

RESUMO

A molecular phylogeny was reconstructed from a culture collection of >150 isolates of epi-endophytic and endophytic green algae, based on nucleotide sequences of the plastid tufA and nuclear ITS2 loci. The cultures were isolated from a variety of algal hosts, notably the red algae Chondrus crispus, Mastocarpus stellatus, and Osmundea species, and the brown algae Chorda filum and Fucus serratus. The phylogeny revealed that in the Ulvales the majority of isolates fell into Acrochaete (Ulvellaceae), Ulva (Ulvaceae), Bolbocoleon (Bolbocoleaceae), and at least two unknown genera provisionally assigned to the Kornmanniaceae. Acrochaete was monophyletic. The genus was also more specious than previously described with 12 species, including up to six new species awaiting formal description. Isolates identified as Acrochaete repens, the type species of the genus, were polyphyletic. The remainder of the isolates were placed in the Ulotrichales. The results confirm that the endophytic habit supports a broad diversity of algal taxa and suggest that blade formation is a relatively recent innovation within the green algae.

15.
J Phycol ; 47(5): 1131-51, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27020195

RESUMO

The red algal order Bangiales has been revised as a result of detailed regional studies and the development of expert local knowledge of Bangiales floras, followed by collaborative global analyses based on wide taxon sampling and molecular analyses. Combined analyses of the nuclear SSU rRNA gene and the plastid RUBISCO LSU (rbcL) gene for 157 Bangiales taxa have been conducted. Fifteen genera of Bangiales, seven filamentous and eight foliose, are recognized. This classification includes five newly described and two resurrected genera. This revision constitutes a major change in understanding relationships and evolution in this order. The genus Porphyra is now restricted to five described species and a number of undescribed species. Other foliose taxa previously placed in Porphyra are now recognized to belong to the genera Boreophyllum gen. nov., Clymene gen. nov., Fuscifolium gen. nov., Lysithea gen. nov., Miuraea gen. nov., Pyropia, and Wildemania. Four of the seven filamentous genera recognized in our analyses already have generic names (Bangia, Dione, Minerva, and Pseudobangia), and are all currently monotypic. The unnamed filamentous genera are clearly composed of multiple species, and few of these species have names. Further research is required: the genus to which the marine taxon Bangia fuscopurpurea belongs is not known, and there are also a large number of species previously described as Porphyra for which nuclear SSU ribosomal RNA (nrSSU) or rbcL sequence data should be obtained so that they can be assigned to the appropriate genus.

16.
Trends Plant Sci ; 16(1): 29-37, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21067966

RESUMO

The marine red alga Porphyra is an important marine crop, worth ∼US$1.3 billion per year. Cultivation research now includes farm ecology, breeding, strain conservation and new net-seeding technologies. The success of cultivation is due, in part, to the high stress tolerance of Porphyra. Many species of Porphyra lose 85-95% of their cellular water during the daytime low tide, when they are also exposed to high light and temperature stress. Antioxidant and mycosporine-like amino acid activities have been partially characterized in Porphyra, but, as we discuss here, the Porphyra umbilicalis genome project will further elucidate proteins associated with stress tolerance. Furthermore, phylogenomic and transcriptomic investigations of Porphyra sensu lato could elucidate tradeoffs made during physiological acclimation and factors associated with life-history evolution in this ancient lineage.


Assuntos
Porphyra/fisiologia , Aminoácidos/análise , Ecologia , Genoma de Planta , Luz , Porphyra/química , Porphyra/genética , Porphyra/crescimento & desenvolvimento , Estresse Fisiológico , Temperatura Ambiente , Água/metabolismo
17.
New Phytol ; 188(1): 30-41, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-20524993

RESUMO

• The origin of the Ectocarpus strain used for genome sequencing (the 'genome strain') was Peru, where no Ectocarpus had been reported previously. To study the genetic diversity in the region and to increase the number of individuals from this area available for genetic experiments, 119 new Ectocarpus strains were isolated from eight localities along the 3000 km of coastline from central Peru to central Chile. • Internal transcribed spacer 1 (ITS1) genotyping revealed nine different genotypes, five of which were endemic to the area studied and three of which were previously unknown. • Individuals of the same genotype as the genome strain occurred from Peru to northernmost Chile, representing 61% of the samples in this area, from which five more genotypes were isolated. Further south, down to central Chile, most individuals belonged to Ectocarpus siliculosus, Ectocarpus fasciculatus and Ectocarpus crouaniorum. In sexual crosses, the genome strain and the new isolates of the same genotype were fully compatible. • Sequences from four nuclear and cytoplasmic genetic markers (ITS1, ITS2, Rubisco spacer and Cytochrome-c oxidase subunit 3 (cox3)) separated the genome strain from the known species of Ectocarpus. It may in future be recognized as a separate species.


Assuntos
Variação Genética , Genoma/genética , Feófitas/genética , Análise de Sequência de DNA , Pareamento de Bases/genética , Sequência de Bases , Chile , DNA Intergênico/genética , Genótipo , Geografia , Dados de Sequência Molecular , Peru , Feófitas/isolamento & purificação , Filogenia
18.
J Phycol ; 45(1): 287-97, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27033664

RESUMO

The Corallinoideae (Corallinaceae) is represented in the northeastern Atlantic by Corallina officinalis L.; Corallina elongata J. Ellis et Sol.; Haliptilon squamatum (L.) H. W. Johans., L. M. Irvine et A. M. Webster; and Jania rubens (L.) J. V. Lamour. The delimitation of these geniculate coralline red algae is based primarily on morphological characters. Molecular analysis based on cox1 and 18S rRNA gene phylogenies supported the division of the Corallinoideae into the tribes Janieae and Corallineae. Within the Janieae, a sequence difference of 46-48 bp (8.6%-8.9%) between specimens of H. squamatum and J. rubens in the cox1 phylogeny leads us to conclude that they are congeneric. J. rubens var. rubens and J. rubens var. corniculata (L.) Yendo clustered together in both phylogenies, suggesting that for those genes, there was no genetic basis for the morphological variation. Within the Corallineae, it appears that in some regions, the name C. elongata has been misapplied. C. officinalis samples formed two clusters that differed by 45-54 bp (8.4%-10.0%), indicating species-level divergence, and morphological differences were sufficient to define two species. One of these clusters was consistent with the morphology of the type specimen of C. officinalis (LINN 1293.9). The other species cluster is therefore described here as Corallina caespitosa sp. nov. This study has demonstrated that there is a clear need for a revision of the genus Corallina to determine the extent of "pseudocryptic" diversity in this group of red algae.

19.
Am J Bot ; 93(8): 1101-8, 2006 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21642175

RESUMO

The red algae, a remarkably diverse group of organisms, are difficult to identify using morphology alone. Following the proposal to use the mitochondrial cytochrome c oxidase subunit I (cox1) for DNA barcoding animals, we assessed the use of this gene in the identification of red algae using 48 samples plus 31 sequences obtained from GenBank. The data set spanned six orders of red algae: the Bangiales, Ceramiales, Corallinales, Gigartinales, Gracilariales and Rhodymeniales. The results indicated that species could be discriminated. Intraspecific variation was between 0 and 4 bp over 539 bp analyzed except in Mastocarpus stellatus (0-14 bp) and Gracilaria gracilis (0-11 bp). Cryptic diversity was found in Bangia fuscopurpurea, Corallina officinalis, G. gracilis, M. stellatus, Porphyra leucosticta and P. umbilicalis. Interspecific variation across all taxa was between 28 and 148 bp, except for G. gracilis and M. stellatus. A comparison of cox1 with the plastid Rubisco spacer for Porphyra species revealed that it was a more sensitive marker in revealing incipient speciation and cryptic diversity. The cox1 gene has the potential to be used for DNA barcoding of red algae, although a good taxonomic foundation coupled with extensive sampling of taxa is essential for the development of an effective identification system.

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