Loci rbcL Research Articles

APPLICATION OF THE DNA BARCODING METHOD FOR IDENTIFICATION AND TAXONOMIC ANALYSIS OF THE LAMIACEAE FAMILY

The Lamiaceae family is one of the largest and most important among the aromatic plants, including many species with pronounced pharmacological properties. Plants of this family, such as mint, rosemary and thyme, are widely used in traditional and modern medicine due to their therapeutic and biochemical properties. The importance of correct species identification is emphasized by the need to preserve the biodiversity and sustainable use of the resources of this family. In this work, plants of Lamiaceae family growing in the territory of the Karaganda region were studied by DNA barcoding. The studies were conducted on the basis of nucleotide sequences of rbcL and trnH-psbA chloroplast DNA barcodes using the methods of paired genetic distances, BLASTn and phylogenetic tree based on the analysis of maximum parsimony. The high efficiency of the rbcL locus was demonstrated for the identification of higher taxonomic groups, such as subfamilies and tribes, while the intergenic spacer trnH-psbAhasproved to be effectiveat the level of speciesandgenus level.

Multiplex Bar-HRM for differentiating Centella asiatica (L.) Urb. from possible substituent species

Global market demand for plant-derived products has increased significantly due to their extensive use in the treatment and prevention of various diseases. However, mislabeling of commercial herbal products poses a major safety concern and affects their efficacy. Differentiating species among Centella asiatica (L.) Urb., Hydrocotyle umbellata L., Bacopa monnieri L., and Bacopa caroliniana (Walter) B.L.Rob, which share morphological features and common local names is challenging. To address this issue, DNA barcoding coupled with high-resolution melting (Bar-HRM) analysis was performed using ITS, matK, and rbcL loci. Suitable primer sets were designed based on nucleotide diversity analysis from multiple alignments of each barcode. Our findings showed that multiplex Bar-HRM (mBar-HRM) using matK1 and rbcL1 successfully discriminated C. asiatica from the other species and enabled contamination detection of C. asiatica and species specificity of various medicinal plants. Analytical sensitivity determined the minimal DNA concentration to generate melting patterns at 0.01 ng per reaction. mBar-HRM was also tested for adulteration detection by mixing DNA from C. asiatica with H. umbellata or B. monnieri at more than 75%. Results demonstrated the potential of mBar-HRM as a reliable method for species authentication in C. asiatica-derived commercial products.

Identification of Egyptian Mangrove Species Based on DNA Barcoding

Aims: Mangroves are woody trees or shrubs that grow in the intertidal zone and are distributed along tropical and subtropical coasts. These plants are resilient to various environmental challenges; they are also one of the most efficient terrestrial and coastal ecosystem for carbon fixation and storage. In recent years, mangrove reforestation has attracted much attention as a strategy to reduce the effects of climate change. In Egypt, there are two types of mangroves, Rhizophora mucronata and Avicennia marina, between 30°N and 30°S of the equator. Mangrove management presents a difficult task, particularly when it comes to managing molecular mangroves for long-term sustainability. With the impact of human activity on mangrove ecosystems increasing each year, molecular research on mangrove correlates remains to be conducted. For this reason, using DNA barcoding technology to quickly identify species, mangrove ecosystems may be protected.
 Methodology: In this work, the two Egyptian mangrove species were assessed through morphological, cytological, and molecular approaches. Two universal DNA barcodes, rbcL and ITS, were examined to identify their efficacy for Egyptian mangrove species identification and phylogenetic reconstruction.
 Results: According to pairwise alignments, the rbcL region had the highest level of variability (73.2%), whereas the ITS region was the least variable (11.96%). The selected Egyptian mangrove species can potentially be distinguished by barcoding loci rbcL and ITS due to the existence of distinctive variable sites.

A combined approach of DNA metabarcoding collectively enhances the detection efficiency of medicinal plants in single and polyherbal formulations.

Empirical research has refined traditional herbal medicinal systems. The traditional market is expanding globally, but inadequate regulatory guidelines, taxonomic knowledge, and resources are causing herbal product adulteration. With the widespread adoption of barcoding and next-generation sequencing, metabarcoding is emerging as a potential tool for detecting labeled and unlabeled plant species in herbal products. This study validated newly designed rbcL and ITS2 metabarcode primers for metabarcoding using in-house mock controls of medicinal plant gDNA pools and biomass pools. The applicability of the multi-barcode sequencing approach was evaluated on 17 single drugs and 15 polyherbal formulations procured from the Indian market. The rbcL metabarcode demonstrated 86.7% and 71.7% detection efficiencies in gDNA plant pools and biomass mock controls, respectively, while the ITS2 metabarcode demonstrated 82.2% and 69.4%. In the gDNA plant pool and biomass pool mock controls, the cumulative detection efficiency increased by 100% and 90%, respectively. A 79% cumulative detection efficiency of both metabarcodes was observed in single drugs, while 76.3% was observed in polyherbal formulations. An average fidelity of 83.6% was observed for targeted plant species present within mock controls and in herbal formulations. In the present study, we achieved increasing cumulative detection efficiency by combining the high universality of the rbcL locus with the high-resolution power of the ITS2 locus in medicinal plants, which shows applicability of multilocus strategies in metabarcoding as a potential tool for the Pharmacovigilance of labeled and unlabeled plant species in herbal formulations.

DNA Barcoding and ITS2 Secondary Structure Predictions in Taro (Colocasia esculenta L. Schott) from the North Eastern Hill Region of India.

Taro (Colocasia esculenta L. Schott, Araceae), an ancient root and tuber crop, is highly polygenic, polyphyletic, and polygeographic in nature, which leads to its rapid genetic erosion. To prevent the perceived loss of taro diversity, species discrimination and genetic conservation of promising taro genotypes need special attention. Reports on genetic discrimination of taro at its center of origin are still untapped. We performed DNA barcoding of twenty promising genotypes of taro indigenous to the northeastern hill region of India, deploying two chloroplast-plastid genes, matK and rbcL, and the ribosomal nuclear gene ITS2. The secondary structure of ITS2 was determined and molecular phylogeny was performed to assess genetic discrimination among the taro genotypes. The matK and rbcL genes were highly efficient (>90%) in amplification and sequencing. However, the ITS2 barcode region achieved significant discrimination among the tested taro genotypes. All the taro genotypes displayed most similar sequences at the conserved matK and rbcL loci. However, distinct sequence lengths were observed in the ITS2 barcode region, revealing accurate discriminations among the genotypes. Multiple barcode markers are unrelated to one another and change independently, providing different estimations of heritable traits and genetic lineages; thus, they are advantageous over a single locus in genetic discrimination studies. A dynamic programming algorithm that used base-pairing interactions within a single nucleic acid polymer or between two polymers transformed the secondary structures into the symbol code data to predict seven different minimum free energy secondary structures. Our analysis strengthens the potential of the ITS2 gene as a potent DNA barcode candidate in the prediction of a valuable secondary structure that would help in genetic discrimination between the genotypes while augmenting future breeding strategies in taro.

Assessment of Rhodolith Diversity in the Northwestern Gulf of Mexico Including the Description of Sporolithon gracile sp. nov. (Sporolithales, Rhodophyta), and Three New Species of Roseolithon (Hapalidiales, Rhodophyta)

In the past, non-geniculate coralline algae in the northwestern Gulf of Mexico have been identified based primarily on comparative morpho-anatomy. Recent studies employing DNA sequencing techniques combined with morpho-anatomical studies using SEM have revealed a wealth of previously undocumented diversity of rhodolith-forming non-geniculate coralline algae in the Corallinales, Hapalidiales and Sporolithales from mesophotic hard bank communities at 45-90 meters depth. Although many advances in the last decade have been made in clarifying species names and describing new species of corallines from offshore Louisiana and Texas, total diversity estimates are still incomplete and many species remain to be described. Collections from offshore Louisiana at Parker Bank in the newly expanded Flower Garden Banks National Marine Sanctuary yielded thin, finely branched rhodoliths. DNA sequence analyses of plastid-encoded psbA and rbcL loci, and nuclear-encoded LSU rDNA of these rhodolith-forming specimens revealed that some belong to an unnamed species of Sporolithon (Sporolithales) that we herein newly describe. Additionally, comparative DNA sequence analyses of rhodolith collections from Ewing Bank and other hard banks offshore Louisiana were conducted to assess rhodolith diversity in these mesophotic communities. The results revealed new reports of taxa for the region, including new rhodolith-forming species of Roseolithon (Hapalidiales) to be described herein as well. Our new biodiversity findings will be compared with historical studies from the NW Gulf of Mexico.

Life on top: cryptoendolithic ascomycetes and microalgae isolated from over 6000 m altitude

Rocks are among the oldest terrestrial niches hosting a multiplicity of life forms, of which diversity has been only partially uncovered. Endolithic metacommunities comprise all major groups of microorganisms, such as chemo-organotrophic, chemo-lithotrophic and phototrophic, represented by bacteria, microalgae and microfungi. Their diversity is often difficult to describe and may remain underestimated. Furthermore, knowledge about the diversity of microorganisms colonizing rocks in peculiar niches is even poorer due to the difficulty to retrieve environmental specimens. Here, we report the phylogenetic and phenotypic characterization of a few endolithic fungi and algae isolated from rock fragments collected at high elevation, i.e., on the top of two mountains over 6000 m altitude, Muztagh Ata (China) and Cerro Mercendario (Argentina). The identity of the strains was confirmed by sequencing the nuclear ITS and LSU, the plastidial rbcL loci and by morphological analysis. Three fungal strains belonging to the class Dothideomycetes and one algal strain belonging to the genus Trebouxia were isolated from Muztagh Ata, while six fungal strains belonging to the order Chaetothyriales and four algal strains belonging to the genus Myrmecia were isolated from Cerro Mercedario. The detected species diversity is discussed in an evolutionary and ecological context.

Multi-methodological approach for the Quality assessment of Senecionis scandentis Herba (Qianliguang) in the herbal market.

We set forth to assess the quality of an herbal medicine sold in Hong Kong called Qianliguang by employing a multi-methodological approach. The quality is set by its identity, chemical composition, and bioactivities, among others. Qianliguang (Senecionis scandentis Herba, Senecio scandens Buch.-Ham. ex D.Don) has known antibacterial properties. However, it is poisonous and overconsumption can result in liver damage. Eighteen Qianliguang samples were purchased from herbal shops at various districts in Hong Kong. Samples were first authenticated organoleptically. DNA barcoding at the psbA-trnH, ITS2, and rbcL loci was then conducted to confirm the species. HPLC-UV was performed to screen for the presence of the chemical compounds and to quantify the flavonoid hyperoside. UPLC-MS was used to quantify the amount of the toxic pyrrolizidine alkaloid (PA) adonifoline. Microdilution assay was performed to show the antibacterial effect on Streptococcus aureus and S. pneumoniae. Results showed that five samples were found to be substituted by species belonging to the genus Lespedeza; four samples were mixtures containing not only Qianliguang but also Achyranthes aspera L., Lonicera confusa DC., or Solanum nigrum L. HPLC-UV showed that only ten contained enough hyperoside to meet the standard requirement. In addition, nine samples had adonifoline that exceeded the toxicity standard requirement. In the microdilution assay, samples containing Qianliguang showed inhibition on S. aureus and S. pneumoniae, while among the five Lespedeza sp. samples the antibacterial effects on S. aureus were not detectable; only one sample showed inhibition to S. pneumoniae. Our study illustrated the necessity of using a multi-methodological approach for herbal medicine quality assessment. We also showed that Qianliguang samples in the Hong Kong market were either toxic or adulterated. It is therefore essential to improve the quality control of Qianliguang and probably other herbs in the herbal market.

Detection of SNPs in Merremia and its related taxa for species identification using DNA barcode markers

Merremiae is one of the least defined tribes in the family Convolvulaceae. It contains number of species which are basically herbs and shrubs. Species identification is a tedious work in the tribe using morphological characters as these traits are often influenced by environmental factors. In the present piece of work, we have analysed five taxa (Merremia umbellata, Merremia vitifolia, Merremia tridentata (Pubescens) and Merremia tridentata (Alatipes) along with one species of Ipomoea - Ipomoea calycina) with help of DNA barcode marker. We have used seven DNA barcoding regions from organellar DNA. Clear and reproducible amplifications were obtained in most of the cases but we failed to observe remarkable variation in amplified fragment size. Variations were detected in the DNA sequence associated with matK and rbcL loci. Sequence analysis showed visible difference between the intra and inter specific genetic distance based on K2P model for both the loci. From the sequenced data we found unique SNPs and In/Dels for the different taxa included in the study. Based upon the matK and rbcL SNP variance table, two dendrograms were constructed and authentication of species of Merremia and its relative were carried out. This work will help in authentic identification of the different taxa in the tribe Merremiae.

RbcL, a potential candidate DNA barcode loci for aconites: conservation of himalayan aconites.

Aconitum heterophyllum Wall. ex Royle and Aconitum balfourii Stapf, are two highly important, threatened medicinal plants of the Indian Himalayan Region. Root-tubers of Aconites have occupied an important place in Indian pharmacopoeia from very ancient times. India is a hub of the wild-collected medicinal herbs industry in Asia and these two aconites are known to have been heavily traded from the region in illicit manner. Prosecution of these illegal trading crimes is hampered by lack of pharma-forensic expertise and tools. Present study was conducted to evaluate the discriminatory potential of rbcL, a Chloroplast based DNA barcode marker for the authentication of these two Himalayan Aconites. Fresh plant samples were collected from their natural distributional range as well as raw materials were procured from herbal market and a total of 32 sequences were generated for the rbcL region. Analysis demonstrated that rbcL region can successfully be used for authentication and importantly, both the aconites, were successfully discriminated by rbcL locus with high bootstrap support (> 50%). Molecular markers could certainly be relied upon morphological and chemical markers being tissue specific, having a higher discriminatory power and not age dependent. Phylogenetic analysis using Maximum Likelihood Method revealed that the rbcL gene could successfully discriminate Himalayan Aconites to species level and have potential to be used in pharma-forensic applications as well as to curb illicit trade of these invaluable medicinal plants.

Barcoding of Some Plant Species Using rbcL Gene ‎in the Mediterranean Oolitic Sand Dunes West of Alexandria, Egypt

In the Mediterranean Basin, Oolitic sand dunes extend along the northeastern coast of Africa between Gulf of Gabes (Tunisia) and the Nile Delta (Egypt) attenuating coastal vulnerability to storms and saltwater intrusion and protecting the inland infrastructure. Psammophytes are the typical and distinctive plants for dunes habitat; they are the primary driver for dune growth and stabilization through trapping sand particles with their shoot and root systems. Anthropocene fingerprint may create an overall environment favorable for non-psammophytes invasion and subsequent alteration in the sand dunes habitat structure and functions. The authentication of sand dunes-inhabiting species should be a priority for conservation or restoration measures concerning sand dunes habitat. The present study is the first rbcL-based DNA barcoding documentation for 20 plant species inhabiting the vulnerable Egyptian oolitic sand dune habitats in Burg El-Arab area, west of Alexandria. The results highlighted the applicability of the rbcL locus sequence for species authentication and recognition of the examined plant taxa sharing the same habitat. The phylogenetic analysis of the rbcL barcodes polymorphism revealed the current taxonomic relationships between the assigned species. However, the ‎results add valuable information to the authentication of sand dune plants where it provided the first rbcL barcodes for species growing in the Egyptian oolitic sand dune-habitat in Egypt of which 6 were submitted for the first time to Gene Bank.

An empirical study on the underutilized medicinal genus Kaempferia from India revealed cytological and genetic variability

The genus Kaempferia L., consisting of aromatic and ornamental species found in east and south-east Asia, have profound ethno-medicinal usages as antimicrobial and anticancer agents, attributable to presence of novel cyclohexane derivatives, flavonoids and di-terpenes. Represented by only 7 species in India, a comprehensive genetic study of Kaempferia from the country is lacking. We present here a study of 4 species of this genus from India, namely, K. rotunda, K. galanga, K. elegans and K. angustifolia. Cytological analyses revealed distinct inter-specific ploidy and consequent somatic chromosome number variations (2n = 22 to 2n = 54). High inter- and intra-chromosomal variability was observed with chromosome lengths ranging from 0.87 to 6.63 µm, constriction types varying from median to sub-median range and different secondary constrictions, along with contrasting values of asymmetry indices. RAPD and ISSR analyses of 8 accessions produced 1,398 polymorphic bands, their sizes ranging from 100 to 2000 bp; percentage polymorphism varying from 84 to 100%. UPGMA dendrogram generated using the polymorphic fragments showed Jaccard's similarity coefficient value varying between 0.07 and 0.93, producing 3 separate clusters for the studied Kaempferia species. ITS, matK and rbcL loci sequence analyses also confirmed high level of inter-specific variability of Kaempferia. Genetic variation revealed in this study could indicate chemotypic differences in Kaempferia and will direct our future research for a wider cytogenetic and phytochemical investigation including all the Indian species that would open up avenues for judicious exploitation of these medicinally important plants.

An update on the indigenous vascular flora of sub-Antarctic Marion Island: taxonomic changes, sequences for DNA barcode loci, and genome size data

The flora of sub-Antarctic Marion Island forms part of the unique South Indian Ocean Biogeographic Province, and is under threat from climate change and invasive species. Current information on the flora is necessary to rapidly identify and manage future changes. We conducted a literature search on the taxonomy of indigenous vascular plant species on Marion Island and found nomenclatural changes following taxonomic revisions for Austroblechnum penna-marina (Poir.) Gasper & V.A.O.Dittrich, Carex dikei (Nelmes) K.L.Wilson, Leptinella plumosa Hook.f., Notogrammitis crassior (Kirk) Parris, Phlegmariurus saururus (Lam.) B.Ollg., and Polypogon magellanicus (Lam.) Finot. Additionally, Ranunculus moseleyi Hook.f. was removed from our species checklist due to its long absence in floristic surveys, leaving 21 species in the indigenous vascular plant flora present on Marion Island. We also amplified and sequenced the universal plant barcoding loci rbcL and matK for 19 and 13 species, respectively, and found that ample interspecific genetic distance and minimal intraspecific genetic distance allowed for easy discrimination between species. Lastly, we obtained genome size estimates using flow cytometry for 12 species. Mean 2C genome size for species on Marion Island ranged from 0.44 to 21.44 pg, which is on the lower end of the known range for vascular plant species. We detected two distinct cytotypes in Poa cookii (Hook.f.) Hook.f. and one cytotype in all other species measured.

Relaciones filogenéticas de especies de plantas que crecen en el desierto florido de la Región de Atacama

Every 3 to 7 year angiosperms species of the flowering desert appear in the Atacama Region of Chile, as a result of the climatic phenomenon El Nino. Our objective was to evaluate the universality of matK and rbcL barcode markers of these species, and validate their taxon through phylogenetic relationships. Argemone hunnemannii, Oenothera coquimbensis, Malesherbia humilis, Leucocoryne appendiculata, Loasa elongata, Nicotiana solanifolia, Stachys grandidentata, Aristolochia chilensis, Alstroemeria kingii and Adesmia eremophila, almost all classified as endemic to Chile, were collected in Pan de Azucar and Llanos de Challe National Park (Atacama Region, Chile) at the end of October 2017. The phylogeny of these ten angiosperm species from the flowering desert was analyzed using rbcL and matK markers with the maximum likelihood and Bayesian inference methods. The results showed that 70% of the species can be distinguished with the matK or rbcL locus, however, 100% were distinguished using both loci. The phylogenetic results showed that the species formed clades with high reliability and high support with both the matK and rbcL genes, when comparing our results with sequences obtained from GenBank. The matK and rbcL genes are efficient markers for analyzing phylogenetic relationships and validating the taxonomy of flowering species.

Chloroplast DNA marker as a tool to study the molecular phylogeny of Indian Barleria L. (Acanthaceae)

Barleria is one of the largest and diversified genus of family Acanthaceae comprising more than 300 species. An enormous repertoire of phytochemicals found within this genus makes it medicinally important taxon. Barleria is classified into two sub-genera i.e., Barleria and Prionitis. However, due to high morphological variability observed within this genus,the sub-generic classification and phylogenetic relationship among different Barleria species remain ambiguous and unclear. Thus, molecular approach was attempted to resolve these discrepancies associated with morphology based classification. In India, Barleria is represented by more than 31 taxa. A high degree of regional endemism has also been observed among different species of this genus. Recent changes in the infra generic classification of Barleria genus also necessitate a thorough study of the group in India as well. Thus, in the present work the systematic position of Indian Barleria was examined with chloroplast (cp) locus i.e., rbcL along with a detailed analysis on the effect of changed circumscription on Indian taxa. Though infra generic classification involving rbcL locus could not be resolved pertaining to a small sample size, we observed genus Barleria as a monophyletic group even after adding Indian taxa.

Systematics of Hymenophyllum subgenus Mecodium (Hymenophyllaceae) in Taiwan

Abstract—Hymenophyllum subg. Mecodium, composed of the taxonomically notorious H. polyanthos and approximately 15 other closely related taxa, is a common element of filmy fern communities in the tropical and subtropical moist forests. In Taiwan, although only H. polyanthos and one or two closely related taxa were recognized in recent studies, considerable morphological variation has been observed among populations throughout the island. Thus, we conducted an extensive morphological investigation, as well as a molecular phylogenetic analysis, to clarify the specific diversity and phylogenetic relationships within Hymenophyllum subg. Mecodium in Taiwan. Field and herbaria surveys helped in recognizing five morphs in Taiwan, mainly differentiated by the combination of certain traits, viz., the presence or absence of stipe wings, general frond size and shape, degree of laminar crispation, sori position, and involucre shape. The different morphs had diverse ecological preferences. The phylogenetic tree, inferred from the sequences of the plastid loci rbcL and rps4-trnS, demonstrated that Hymenophyllum subg. Mecodium materials in Taiwan comprise several well-supported lineages, mostly corresponding to the classification based on morphology. Comparing with the protologues and type specimens of 34 related scientific names, the five morphs are herein recognized as five independent species. A new species, Hymenophyllum exquisitum, is described here. Also, the status of H. paniculiflorum is reconfirmed and that of H. fujisanense, H. parallelocarpum, and H. punctisorum reinstated. Only H. exquisitum and H. parallelocarpum are endemic to Taiwan among all the species studied. In addition, the names Hymenophyllum blumeanum, H. integrum, H. microsorum, H. polyanthos, H. tenellum, and H. wrightii are now excluded from the regional flora, and several related taxa from China, Taiwan, and the Philippines are treated as synonyms. This study unravels the deep phylogenetic relationships within Hymenophyllum subg. Mecodium in Taiwan and Eastern Asia.

<p><strong><em>Sporolithon amadoi </em>sp. nov. (Sporolithales, Rhodophyta), a new rhodolith-forming non-geniculate coralline alga from offshore the northwestern Gulf of Mexico and Brazil</strong></p>

DNA sequence analysis of plastid-encoded psbA and rbcL loci, and nuclear-encoded LSU rDNA of rhodolith-forming specimens of Sporolithales from Brazil and the northwestern Gulf of Mexico reveal that they belong to an unnamed species of Sporolithon (Sporolithaceae). Sporolithon amadoi sp. nov. is morpho-anatomically characterized by a vegetative thallus reaching more than 20 cell layers, a tetrasporophyte with tetrasporangial sori slightly raised above the thallus surface that become overgrown and buried after spore release, and by cruciately divided tetrasporangia with pores surrounded by 9–13 rosette cells. Since these morpho-anatomical features are shared with some other Sporolithon species, identification of this species can only be confirmed by DNA sequences.

Detection of adulteration in black gram-based food products using DNA barcoding

DNA barcoding is gaining importance in food authenticity studies due to its sensitivity, reliability and accuracy in identification of adulterant species from pure food commodity. In the present study, three barcoding loci viz., rbcL, trnH-psbA and ITS were explored to test their potential in detection of adulteration of black gram flour and its products with refined wheat flour (maida) and white pea flour. All three loci exhibited 100% success rate of PCR amplification and sequencing. Amplicons of band size 600 bp, 380 bp and 680 bp were obtained for rbcL, trnH-psbA and ITS, respectively. The method was validated on simulated samples of black gram flour (variety TPU-4) adulterated with 5% each of refined wheat flour and white pea flour. Sequence analysis and BLAST searches of the model blends revealed the presence of these two potential adulterants, thereby making the method sensitive enough to detect adulteration at 5% level. Among the 3 loci studied, loci rbcL and trnH-psbA, served as ideal candidates for detection of refined wheat flour adulteration in black gram flour. Eleven market samples of black gram products such as flour, papad, instant medu vada mix and papad atta of different brands were analysed using DNA barcoding. The method could successfully detect the presence of refined wheat flour in one of the papad samples. Therefore, molecular identification of black gram flour products and its adulterants can be done using the developed DNA barcoding method based on rbcL and trnH-psbA sequences.

Sporolithon mesophoticum sp. nov. (Sporolithales, Rhodophyta) from Plantagenet Bank off Bermuda at a depth of 178 m

A coralline rhodolith was collected from a depth of 178 m, the lower end of the mesophotic zone, on Plantagenet Bank offshore of Bermuda by the submersible Nomad using a mechanical armature. DNA sequence comparisons of the plastid encoded psbA and rbcL loci of this specimen to Sporolithales from the tropical western Atlantic and worldwide revealed it to be an unnamed species of Sporolithon. Sporolithon mesophoticum sp. nov. possesses tetrasporangial sori flush to slightly raised above the thallus surface and has uniquely flattened perithallial and meristematic cells. Thus far, the new species is the deepest known living marine macroalga that has been sequenced and placed into a phylogenetic context.

Description of a new diatom genus Dorofeyukea gen. nov. with remarks on phylogeny of the family Stauroneidaceae.

Type material of Navicula kotschyi was studied, and this species was transferred to Dorofeyukea gen. nov. as D.kotschyi comb. nov. Dorofeyukea was described on the basis of DNA sequence and morphological data. Additional species assigned to this genus that were previously included in Navicula include: D.ancisa comb. nov., D.grimmei comb. nov., D.ivatoensis comb.nov., D.orangiana comb. nov., D.rostellata comb. nov. & stat. nov., D.savannahiana comb. nov., D.tenuipunctata comb. nov., and D.texana comb. nov. All Dorofeyukea species share the same morphological features, including having a narrow stauroid fascia surrounded by 1-3 irregularly shortened striae, uniseriate, and weakly radiate striae, circular, or rectangular puncta in the striae that are covered internally by dome-shaped hymenes, presence of a pseudoseptum at each apex and absence of septa. Partial DNA sequences of SSU and rbcL loci show Dorofeuykae belongs to the clade of stauroneioid diatoms together with Stauroneis, Prestauroneis, Craticula, Karayevia, Madinithidium, Fistulifera, Parlibellus, and, possibly, Schizostauron. A new species from the monoraphid genus Madinithidium, M.vietnamica sp. nov., was described based on valve and chloroplast morphology as well as DNA sequence data.