Daniela Milstein

A NEW LOOK AT AN ANCIENT ORDER: GENERIC REVISION OF THE BANGIALES (RHODOPHYTA)†

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.

A NEW LOOK AT AN ANCIENT ORDER: GENERIC REVISION OF THE BANGIALES (RHODOPHYTA)(1).

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.

Molecular phylogeny of Bangiales (Rhodophyta) based on small subunit rDNA sequencing: emphasis on Brazilian Porphyra species

D. Milstein and M. C. de Oliveira. 2005. Molecular phylogeny of Bangiales (Rhodophyta) based on small subunit rDNA sequencing: emphasis on Brazilian Porphyra species. Phycologia 44: 212–221. In an attempt to clarify the position of the Brazilian Porphyra species within the order Bangiales, phylogenetic trees were inferred on the basis of nuclear small subunit ribosomal RNA gene (SSU rDNA) sequences. The internal transcribed spacers ITS-1 and ITS-2 and the 5.8S rRNA gene were sequenced for discrimination of the closely related species Porphyra drewiana, P. spiralis var. spiralis and P. spiralis var. amplifolia. Occurrence of SSU rDNA group I introns is reported for some Porphyra species and a novel position for a group I intron is described for Bangiopsis sp. (Porphyridiales). The Brazilian species, P. acanthophora var. acanthophora, P. acanthophora var. brasiliensis, P. drewiana, P. spiralis var. amplifolia, P. spiralis var. spiralis and Porphyra sp. ‘Piaui’ formed a monophyletic group within a large polytomy that includes Bangia collections and Porphyra species from distinct locations. The Brazilian species Porphyra sp. ‘Baleia’ grouped strongly with P. suborbiculata from Japan and New Zealand, indicating that this cosmopolitan species also occurs in the South Atlantic. South African P. capensis grouped with two New Zealand species.

A new look at an ancient order: generic revision of the Bangiales

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.

Will a DNA barcoding approach be useful to identify Porphyra species (Bangiales, Rhodophyta)?

This paper is part of an extensive study on the biodiversity of the macroalgal flora of São Paulo state, SE Brazil. Previous assessments were based only on morphological descriptions. Here, we tested the effectiveness of DNA barcoding, in comparison with morphological observations for the recognition and cataloging of species. The focus of this study is the genus Porphyra, which is a conspicuous component of the upper intertidal on rocky shores of this region. With five currently accepted species, we have sequenced three short markers: cox1, cox2–3 spacer and UPA to establish the first DNA barcode database for the Porphyra species from the Brazilian coast. The three markers, although with different evolution rates, recovered a cryptic species (Porphyra sp. 77), grouped two different species (Porphyra drewiana and Porphyra spiralis) that are being synonymized, and finally indicated that varieties within P. acanthophora and P. spiralis are merely morphological, with no sequence divergence in the studied molecular markers.

Group I introns and associated homing endonuclease genes reveals a clinal structure for Porphyra spiralis var. amplifolia (Bangiales, Rhodophyta) along the Eastern coast of South America

BackgroundGroup I introns are found in the nuclear small subunit ribosomal RNA gene (SSU rDNA) of some species of the genus Porphyra (Bangiales, Rhodophyta). Size polymorphisms in group I introns has been interpreted as the result of the degeneration of homing endonuclease genes (HEG) inserted in peripheral loops of intron paired elements. In this study, intron size polymorphisms were characterized for different Porphyra spiralis var. amplifolia (PSA) populations on the Southern Brazilian coast, and were used to infer genetic relationships and genetic structure of these PSA populations, in addition to cox2-3 and rbcL-S regions. Introns of different sizes were tested qualitatively for in vitro self-splicing.ResultsFive intron size polymorphisms within 17 haplotypes were obtained from 80 individuals representing eight localities along the distribution of PSA in the Eastern coast of South America. In order to infer genetic structure and genetic relationships of PSA, these polymorphisms and haplotypes were used as markers for pairwise Fst analyses, Mantels test and median joining network. The five cox2-3 haplotypes and the unique rbcL-S haplotype were used as markers for summary statistics, neutrality tests Tajimas D and Fus Fs and for median joining network analyses. An event of demographic expansion from a population with low effective number, followed by a pattern of isolation by distance was obtained for PSA populations with the three analyses. In vitro experiments have shown that introns of different lengths were able to self-splice from pre-RNA transcripts.ConclusionThe findings indicated that degenerated HEGs are reminiscent of the presence of a full-length and functional HEG, once fixed for PSA populations. The cline of HEG degeneration determined the pattern of isolation by distance. Analyses with the other markers indicated an event of demographic expansion from a population with low effective number. The different degrees of degeneration of the HEG do not refrain intron self-splicing. To our knowledge, this was the first study to address intraspecific evolutionary history of a nuclear group I intron; to use nuclear, mitochondrial and chloroplast DNA for population level analyses of Porphyra; and intron size polymorphism as a marker for population genetics.

Native or introduced? A re-evaluation of Pyropia species (Bangiales, Rhodophyta) from Brazil based on molecular analyses

The genus Porphyra sensu lato of the Bangiales has been reported from the Brazilian coast since the 19th century. However, a major worldwide taxonomic revision of the Bangiales indicated that the foliose genus present in Brazil was Pyropia and that Porphyra sensu stricto has not been recorded from this region. A revision of the species of Pyropia in Brazil, based on sequence analysis of molecular markers (rbcL and SSU rDNA) and complemented with morphology, revealed the occurrence of five distinct species in Brazil: P. acanthophora, P. spiralis, P. suborbiculata, P. tanegashimensis and P. vietnamensis. Possible events of Pyropia species introduction in Brazil are discussed in the context of phylogenetic analyses. Pyropia acanthophora and P. spiralis, regarded as southwestern Atlantic species, were not closely related in phylogenetic analyses. Pyropia acanthophora grouped with the possibly introduced Indo-Pacific species P. suborbiculata, P. tanegashimensis and P. vietnamensis. Analysis of available COI-5P and UPA sequences indicated that P. acanthophora occurs in the Hawaiian Islands. These results suggest that P. acanthophora, contrary to previous views, may not be endemic to Brazil. Pyropia spiralis, which is supposedly the only native Pyropia species in Brazil, grouped with species from the Mexican Pacific coast, and its origin along the southwestern Atlantic Ocean and Caribbean Sea is discussed.

DNA barcoding reveals high diversity in the Gelidiales of the Brazilian southeast coast

Abstract Morphological identification of species in the order Gelidiales can be difficult and controversial because of phenotypic plasticity, the low numbers of reproductive specimens and poorly defined taxonomic boundaries. A DNA barcoding survey of Brazilian specimens of Gelidiales, employing neighbor-joining and Automatic Barcode Gap Discovery analyses, indicated the presence of 23 statistically robust primary species hypotheses (PSH). In addition to the cytochrome oxidase I gene (COI-5P), the chloroplast universal plastid amplicon (UPA) marker was also sequenced and submitted to the same analyses. Representatives of each COI-5P/UPA PSH were selected for rbcL sequence analysis to further corroborate the occurrence of 23 species and to infer their phylogenetic relationships. These analyses confirmed the identity of six species previously cited for Brazil: Gelidiella acerosa, G. ligulata, Gelidium crinale, G. floridanum, Pterocladiella bartlettii and P. capillacea. Three new reports for Brazil were also detected: Gelidium microdonticum, Pterocladiella beachiae and P. australafricanensis. Fourteen species remain unidentified and require detailed morphological evaluation.

DNA barcoding of Canadian Ahnfeltiales (Rhodophyta) reveals a new species – Ahnfeltia borealis sp. nov

Milstein D. and Saunders G.W. 2012. DNA barcoding of Canadian Ahnfeltiales (Rhodophyta) reveals a new species – Ahnfeltia borealis sp. nov. Phycologia 51: 247–259. DOI: 10.2216/11-40.1 The red algal genus Ahnfeltia has only two described species in Canada, Ahnfeltia fastigiata and Ahnfeltia plicata, occurring along the North Pacific and North Atlantic coasts, respectively. However, during an ongoing molecular-based floristic survey of Canadian marine algae using the mitochondrial 5′ end of the cytochrome c oxidase I gene as a screening tool, cryptic diversity was uncovered, indicating the presence of four genetic lineages. These genetic clusters were further characterized using the nuclear ribosomal internal transcribed spacers and the variable domain V of the plastid large subunit (23S) ribosomal gene (universal plastid amplicon), as well as morphological and anatomical observations. Our data indicate the presence of a third species of Ahnfeltia, A. borealis sp. nov., which is typically subarctic in its distribution and intermediate in many key anatomical features between A. fastigiata and A. plicata.

The floating Sargassum (Phaeophyceae) of the South Atlantic Ocean – likely scenarios

Abstract: This study represents the efforts of a network of researchers to characterise the large, floating Sargassum (Fucales, Phaeophyceae) biomass that had reached the Brazilian coast in 2014 and 2015. Material collected during these events was identified as Sargassum natans and S. fluitans using morphological characteristics; ITS2 sequences showed low divergence (0%–3%) with sequences of nine other Sargassum species. Several epiphytic macroalgae, invertebrates and fishes were associated with the floating Sargassum. Satellite images did not support the hypothesis of slicks moving south from the Sargasso Sea in the northern Atlantic Ocean. This strengthens the hypothesis that there is a matrix of pelagic Sargassum in the central Atlantic Ocean and that biomass accumulation should be considered a result of the combination of physicochemical seawater conditions and biological interactions. The biomass accumulation of the stranded Sargassum was estimated during four events, peaking in 98 kg m−2 wet weight on a beach on the Amazonian coast. The landing of huge Sargassum biomass represents a potential source of environmental stress, as it can lead to an increase in oxygen demand and eventually synthesise and release chemical compounds with allelopathic properties. On the other hand, these floating islands are a fundamental element of the biogeography and macroecology of tropical environments in the Atlantic Ocean, providing connectivity south/north and east/west among marine biodiversity from Atlantic reef environments. Studies concerning Sargassum effects on local communities are necessary for the proper management of this phenomenon.