Molecular Phylogeny Analysis Research Articles

Molecular detection and phylogeny analysis of Coxiella burnetii detected from cattle and buffalo milk based on plasmid cbhE gene in West Azerbaijan of Iran

Humans and animals may get Q fever, which is caused by the Gram-negative coccobacillus Coxiella burnetii. The symptoms of Q fever may include a self-limiting febrile illness, pneumonia, endocarditis, or hepatitis. Infections are classified as either acute or persistent. Cattle, sheep, and goats are the most prevalent reservoir animals for this zoonosis. This research was conducted to identify C. burnetii using transposable and isocitrate dehydrogenase genes (IS1111, icd) and QpH1 plasmids. A total of 142 samples of raw buffalo and cow milk were collected from various locations within the West Azerbaijan region (see map). We used "nested" PCR techniques using primers based on the IS1111 and icd genes of C. burnetii, as well as conserved and variable portions of plasmid sequences, to identify C. burnetii and their plasmids in milk samples from buffalo and calves. Out of 142 milk samples that were positive for the chromosomal transposable genes (IS1111 and icd) at a rate of 16.9 percent (95 percent CI: 14.5 percent to 19.6 percent) and 7.1 % (95 percent CI: 5.59 percent to 9.08 percent), respectively, 86 samples were positive for the QpH1 plasmid at a rate of 60.5 percent (95 percent CI: 52.35 percent to 68.2 percent). Based on a phylogenetic study of the icd and QpH1 genes, the majority of the isolates had a similarity of 99.45–99.9 percent. Conclusion: It was determined that the buffalo population in West Azerbaijan province represents a significant epidemiological factor with respect to Q fever and consequently public health.

Morphological and Phylogenetic Analysis Reveals Two New National Records of Viola (Violaceae) from Southwestern China

Two rarely reported violets, Viola annamensis Baker f. and V. rheophila Okamoto were confirmed as new additions to the flora of China, based on three collections from Yunnan and Guangxi, southwestern China. Molecular phylogeny analysis based on nrITS dataset was conducted to facilitate further identification and their phylogenetic position. A brief description of the two new recorded species were also presented.

Cortinarius steglichii: a taxonomical and chemical novelty from Chile

The new species Cortinarius steglichii is described from Chilean Nothofagus forest based on morphological and microscopical attributes, molecular phylogeny, and chemical analysis of secondary metabolites. C. steglichii is characterized by abundant, long, ramified cystidia on the lamellar edges and stipe apex, further by a deep violet color reaction after treatment with KOH. As responsible secondary metabolite for the cytoplasmatic color reaction of cystidia and some hyphae, the new diterpenoid steglichon (1) could be recognized, showing also remarkable antibacterial and anticancer activity. Phylogenetic analyses (ITS, LSU, RPB1) confirm the close relationship to species of the Cortinarius dulciolens group.

Novel discoveries of Xylariomycetidae (Ascomycota) taxa from peat swamp forests and other terrestrial habitats in Thailand.

In a comprehensive survey of fungi conducted in the northern (Chiang Rai Province) and southern (Narathiwat Province) regions of Thailand, several xylariales-like specimens were discovered. Through the integration of molecular phylogeny and morphological analyses, one previously undocumented taxon, Oxydothisnarathiwatensis sp. nov., was identified, along with Xylariabawanglingensis and Hypoxylonhypomiltum as new host and geographical records from Afzeliaxylocarpa, and Dalbergiacana, respectively. In addition, Annulohypoxylonthailandicum was identified as a new host record from Swieteniamacrophylla in Thailand. The morphological characters, including ascomata, asci, and ascospores, were compared with known Oxydothis, Xylaria, Hypoxylon, and Annulohypoxylon species. Multi-locus phylogenetic analyses based on ITS, LSU, and SSU (for Oxydothidaceae), ITS, rpb2, tub2, and act (for Xylariaceae), and ITS, LSU, rpb2, and tub2 (for Hypoxylaceae) gene regions were carried out to refine the taxonomic classifications of these specimens further. This research contributes to understanding fungal diversity in these ecologically significant regions, highlighting insights into the relationships among xylariales-like species.

NLRP3, NLRP6, and NLRP12 are inflammasomes with distinct expression patterns.

Inflammasomes are sensors that detect cytosolic microbial molecules or cellular damage, and in response they initiate a form of lytic regulated cell death called pyroptosis. Inflammasomes signal via homotypic protein-protein interactions where CARD or PYD domains are crucial for recruiting downstream partners. Here, we screened these domains from NLR family proteins, and found that the PYD domain of NLRP6 and NLRP12 could activate caspase-1 to induce cleavage of IL-1β and GSDMD. Inflammasome reconstitution verified that full length NLRP6 and NLRP12 formed inflammasomes in vitro, and NLRP6 was more prone to auto-activation. NLRP6 was highly expressed in intestinal epithelial cells (IEC), but not in immune cells. Molecular phylogeny analysis found that NLRP12 was closely related to NLRP3, but the activation mechanisms are different. NLRP3 was highly expressed in monocytes and macrophages, and was modestly but appreciably expressed in neutrophils. In contrast, NLRP12 was specifically expressed in neutrophils and eosinophils, but was not detectable in macrophages. NLRP12 mutations cause a periodic fever syndrome called NLRP12 autoinflammatory disease. We found that several of these patient mutations caused spontaneous activation of caspase-1 in vitro, which likely causes their autoinflammatory disease. Different cell types have unique cellular physiology and structures which could be perturbed by a pathogen, necessitating expression of distinct inflammasome sensors to monitor for signs of infection.

Analyses of the Mx family members in lumpfish: Molecular characterization, phylogeny, and gene expression analyses

Members of the myxovirus resistance (Mx) protein family play an essential role in antiviral immunity. They are Dynamin-like GTPases, induced by interferons. In the current study, we have characterized two predicted MX genes (MX1 and MX2) from lumpfish (Cyclopterus lumpus L.), having 12 and 13 exons, respectively. Mx2 has two isoforms (Mx2-X1 and Mx2-X2) which differ in exon 1. The lumpfish Mx proteins contain an N-terminal Dynamin-like GTPase domain, the middle domain (MD) and GTPase effector domain (GED) characteristic for Mx proteins. Phylogenetic analyses grouped all the lumpfish Mx sequences in group 1, and synteny analyses showed that both genes were localized at chromosome 5 in proximity to the genes Tohc7, Atxn7 and Psmd6. In vitro stimulation experiment showed that both MX1 and MX2-X2 were highly upregulated upon exposure to poly(I:C), but not bacteria, 24 h post exposure, indicating their role in antiviral immunity.

Sporochnus keyari sp. nov. (Sporochnales, Phaeophyceae) from Japan

ABSTRACT In the genus Sporochnus (Sporochnales, Phaeophyceae), Okamura reported S. radiciformis and S. scoparius in Japan in 1922; however, S. scoparius was later synonymized with S. radiciformis, as Okamura’s S. radiciformis was considered to be a young stage of S. scoparius. Therefore, only one species, S. radiciformis, has been recognized in Japan, until the reported occurrence of a second species, S. dotyi, and suggestion that the species identified as S. radiciformis in Japan was genetically distinct from true S. radiciformis described from Australia. We now report findings that based on molecular phylogeny (atpB, rbcL, atp6, cox3) and morpho-anatomical analyses confirming that the common Japanese Sporochnus species is distinct from true S. radiciformis, and we therefore describe a new species, S. keyari sp. nov. This new species differs from S. radiciformis in having less-branched erect thalli, longer terminal assimilatory filaments (trichothallic hairs), and larger unilocular zooidangia, and from S. bolleanus in having more robust thallus axes. In gross morphology, S. keyari is distinguished from S. dotyi, which is also distributed in Japan, in having more slender thalli and lacking greenish structural colour of the assimilatory filaments. In culture, unizoids (zoospores) released from unilocular zooidangia developed into monoicous gametophytes forming antheridia and oogonia at the distal ends of the filaments. Actual sexual fusion was not observed, but presumably fertilization occurred within oogonia and new sporophytes developed in situ within oogonia. Sporophytes were at first uniseriate, but later formed terete thalli by trichothallic growth, with terminal assimilatory filaments.

Complete Mitochondrial Genomes and Phylogenetic Analysis of Genus Henricia (Asteroidea: Spinulosida: Echinasteridae).

The genus Henricia is known to have intraspecific morphological variations, making species identification difficult. Therefore, molecular phylogeny analysis based on genetic characteristics is valuable for species identification. We present complete mitochondrial genomic sequences of Henricia longispina aleutica, H. reniossa, and H. sanguinolenta for the first time in this study. This study will make a significant contribution to our understanding of Henricia species and its relationships within the class Asteroidea. Lengths of mitochondrial genomes of the three species are 16,217, 16,223, and 16,194 bp, respectively, with a circular form. These genomes contained 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA genes, and a D-loop. The gene order and direction aligned with other asteroid species. Phylogenetic relationship analysis showed that our Henricia species were in a monophyletic clade with other Henricia species and in a large clade with species (Echinaster brasiliensis) from the same family. These findings provide valuable insight into understanding the phylogenetic relationships of species in the genus Henricia.

Molecular phylogeny and secondary structure analysis of hop stunt viroid (HSVd) associated with Mulberry (Morus alba) in India.

Hop stunt viroid (HSVd), a small, single stranded, circular, non-coding infectious RNA known to cause infection in various economically important crop plants. In the present investigation, a study was conducted in the southern part of Karnataka districts of India to detect the possible association of HSVd infection in mulberry plants. A total of 41 mulberry plants showing typical viroid-like symptoms along with asymptomatic samples were collected and screened using conventional Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) using a specific set of HSVd-Fw/ HSVd-Re primers. Out of 41 samples, the study confirmed the presence of HSVd in six samples of mulberry collected from Ramanagara (1 sample), Chikkaballapur (3 samples) and Doddaballapura (2 samples) regions with an expected HSVd amplicon size of ∼ 290-300 nucleotides. The mechanical transmission of HSVd was also confirmed on cucumber (cv. Suyo) seedlings through bioassay, which was reconfirmed by RT-PCR. The amplicons were cloned, sequenced, and the representative nucleotide sequences were deposited in the NCBI GenBank. Subsequently, molecular phylogenetic analysis showed that HSVd mulberry isolates from this study were most closely related to grapevine isolates, indicating a common origin. On the other hand, it was shown to belong to a different group from mulberry isolates so far reported from Iran, Italy, Lebanon, and China. The secondary structure analysis of HSVd mulberry Indian isolates exhibited substitutions in the terminal left, pathogenicity, and variable regions compared to those of the Indian grapevine isolates. As far as this study is concerned, HSVd was detected exclusively in some mulberry plants with viral-like symptoms, but the pathogenesis and symptom expression needs to be further investigated to establish the relationship between HSVd and the disease symptoms in the mulberry plants.

Molecular phylogeny and ethology of the Family Plagiostomidae (Platyhelminthes, Prolecithophora), with integrative description of a new species, Plagiostomum robusta A. Wang, sp. nov.

The taxon Prolecithophora, which is closely related to the well-known clade Tricladida, is rarely studied, particularly in terms of molecular phylogeny and behavioral characteristics. In this study, we employed an integrative analysis of molecular phylogeny, histology, and ethology to describe a new marine species, Plagiostomum robusta A.Wang, sp. nov. of the order Prolecithophora. Additionally, we obtained its nearly complete mitogenome sequence with annotations of 12 protein-coding genes, two rRNA genes and 22 tRNA genes. P. robusta is characterized by several features, including a pair of short tentacles, a terminal mouth and a terminal gonopore, a large variable pharynx, two extended front ends of the intestine, paired testes located behind the ovaries and outside the vitellaria, a muscular and movable distal sac, and a long tubular penis surrounded by a sheath. The phylogenetic analysis, based on 18S rDNA and 28S rDNA, revealed that the new species formed a clade with six Plagiostomum flatworms, indicating a close kinship with Plagiostomum. Despite contradictions between the traditional morphological classification system and the results of molecular phylogenetics, we chose to assign the new species to Plagiostomum based on comprehensive considerations. Moreover, our study has provided more insights into the behavioral features of Plagiostomidae species, as we found that P. robusta fed on other flatworms and engaged in cannibalism, and unexpectedly it mated via hypodermic inpregnation. This study represents the first comprehensive description of the reproductive behavior of Plagiostomidae species, contributing to the more in-depth understanding of the biological characteristics of this group.

A novel in-situ-process technique constructs whole circular cpDNA library

BackgroundThe chloroplast genome (cp genome) is directly related to the study and analysis of molecular phylogeny and evolution of plants in the phylogenomics era. The cp genome, whereas, is highly plastic and exists as a heterogeneous mixture of sizes and physical conformations. It is advantageous to purify/enrich the circular chloroplast DNA (cpDNA) to reduce sequence complexity in cp genome research. Large-insert, ordered DNA libraries are more practical for genomics research than conventional, unordered ones. From this, a technique of constructing the ordered BAC library with the goal-insert cpDNA fragment is developed in this paper.ResultsThis novel in-situ-process technique will efficiently extract circular cpDNA from crops and construct a high-quality cpDNA library. The protocol combines the in-situ chloroplast lysis for the high-purity circular cpDNA with the in-situ substitute/ligation for the high-quality cpDNA library. Individually, a series of original buffers/solutions and optimized procedures for chloroplast lysis in-situ is different than bacterial lysis in-situ; the in-situ substitute/ligation that reacts on the MCE membrane is suitable for constructing the goal-insert, ordered cpDNA library while preventing the large-insert cpDNA fragment breakage. The goal-insert, ordered cpDNA library is arrayed on the microtiter plate by three colonies with the definite cpDNA fragment that are homologous-corresponds to the whole circular cpDNA of the chloroplast.ConclusionThe novel in-situ-process technique amply furtherance of research in genome-wide functional analysis and characterization of chloroplasts, such as genome sequencing, bioinformatics analysis, cloning, physical mapping, molecular phylogeny and evolution.

Identification and antifungal sensitivity of Fusarium species isolated from piscine hosts.

Fusarium is a huge genus of filamentous fungi that has the potential to cause emerging diseases. Members of this genus can cause infections in plants, animals and humans. Here, we report the isolation of F. oxysporum and F. equiseti from 2 important fish species, Oncorhynchus mykiss (rainbow trout) and Tor putitora (golden mahseer), respectively. F. oxysporum has emerged as a significant fungal pathogen causing infection in many fish. However, F. equiseti has been isolated mainly from plants. As far as the available literatures are concerned, this is the first report on the isolation of F. oxysporum and F. equiseti from these hosts. The isolates were identified based on growth morphology and microscopic observation. F. oxysporum produced violet pigmentation on potato dextrose agar, while F. equiseti had yellow colouration. F. oxysporum produced 1- to 2-celled microconidia along with straight or curved macroconidia having 3 to 4 septa. F. equiseti produced abundant macroconidia with 4 or more septa. Species were further confirmed based on the nucleotide sequences of the internal transcribed spacer region. In a molecular phylogeny analysis, F. oxysporum and F. equiseti formed 2 different clades. In an antifungal sensitivity assay, F. oxysporum was found to be susceptible to clotrimazole with a minimum inhibitory concentration of 1.0 µg ml-1, whereas F. equiseti was susceptible to clotrimazole, ketoconazole and fluconazole. Overall, the main findings of this study are the infection of new hosts by Fusarium species and the limited activity of many antifungal drugs against these pathogens.

Molecular detection of Batrachochytrium dendrobatidis (Chytridiomycota) and culturable skin bacteria associated with three critically endangered species of Atelopus (Anura: Bufonidae) in Ecuador.

Chytridiomycosis is a fungal disease responsible for massive amphibian die-offs worldwide, caused by the fungus Batrachochytrium dendrobatidis (Bd). Potential symbiotic relationships between frogs and the bacteria residing on their skin-referred to as skin-bacteria-may inhibit Bd growth, aiding in resistance to this lethal disease. This research had three main objectives: (1) to detect the presence of Bd in native populations of Atelopus balios, A. bomolochos, and A. nanay in the central Andes and coastal southern regions of Ecuador; (2) to identify the culturable skin-bacteria; and (3) to analyze differences among the bacterial communities in the three Atelopus species studied. Skin swabs were collected from two populations of A. balios (107-203 m a.s.l.) and one population each of A. bomolochos and A. nanay (3,064-3,800 m a.s.l.). These swabs served two purposes: first, to detect Bd using conventional PCR; and second, to isolate culturable bacteria, which were characterized through DNA sequencing, molecular phylogeny, and community composition similarity analysis (Jaccard index). Results showed that Bd was present in all species, with positive Bd PCR amplification found in 11 of the 12 sampled amphibians. The culturable skin-bacteria were classified into 10 genera: Pseudomonas (31.4%), Stenotrophomonas (14.3%), Acinetobacter (11.4%), Serratia (11.4%), Aeromonas (5.7%), Brucella (5.7%), Klebsiella (5.7%), Microbacterium (5.7%), Rhodococcus (5.7%), and Lelliottia (2.9%). The Jaccard index revealed that bacterial genera were least similar in A. bomolochos and A. balios (J=0.10), while the highest similarity at the genus level was between A. bomolochos and A. nanay (J=0.33). At the clade-species level, only A. bomolochos and A. nanay show common bacteria (J=0.13). Culturable bacterial communities of specimens diagnosed as Bd positive (n=10) or Bd negative (n=1) share a J value of 0.1 at genus and 0.04 at species-clade level. The prevalence of Bd and the composition of cutaneous bacteria could be influenced by Bd reservoirs, Atelopus biology, and intrinsic environmental conditions. This research contributes to understanding the relationship between endangered Andean species and Bd, and explores the potential use of native skin-bacteria as biocontrol agents against Bd.

Phylogenetic position inferred on SSU rDNA sequence gene and description of a new parasitic cnidarian (Endocnidozoa: Myxobolidae) infecting Markiana nigripinnis (Teleostei: Stevardiinae) from a small marginal lake floodplain, Brazil.

Herein, a detailed molecular phylogeny analysis was developed to determine the phylogenetic position of a new freshwater histozoic myxosporean cnidarian, Henneguya markiana sp. nov. from the world's largest tropical wetland area, Pantanal, Brazil. The new species is described using an integrative taxonomy approach including morphology, biological traits and molecular data. Phylogenetic analysis inferred by Maximum Likehood method showed the new Henneguya species in a well-supported clade of myxosporean gill parasites of South American characids fishes. In this same clade, the new Henneguya described appeared in a sub-clade clustering with H. lacustris and H. chydadea. Nevertheless, the sequences of the new species and H. lacustris and H. chydadea have a large genetic divergence of 10.4% (148 nucleotides-nt) and 10.5% (147 nt) respectively. To the best of our knowledge, this is the first report of a cnidarian myxosporean species parasitizing a fish from Stevardiinae from South America. In the light of the differences observed from the integrative taxonomy, we are confident that this isolate is a new species of Henneguya, increasing the knowledge of diversity of this enigmatic group of cnidarians.

Analysis of geometric morphometrics and molecular phylogeny for Anopheles species in the Republic of Korea

Human malaria, transmitted by Anopheles mosquitoes, is the most predominant mosquito-borne disease that is responsible for hundreds of thousands of deaths worldwide each year. In the Republic of Korea (ROK), there are currently several hundred malaria cases annually, mostly near the demilitarized zone (DMZ). Eight species of Anopheles mosquitoes are currently known to be present in the ROK. Similar to other major malaria vectors in Africa and India, it is very challenging to morphologically differentiate Anopheles mosquitoes in the ROK due to their extremely similar morphology. In this study, wing geometric morphometrics (WGM) were used to differentiate the eight Anopheles species collected at six locations near the DMZ, Seoul and Pyeongtaek from April–October 2021. Phylogenetic analysis was also performed using cytochrome c oxidase subunit 1 (COI), internal transcribed spacer 2 (ITS2), and tyrosine hydroxylase (TH) genes for comparison with WGM analysis and to infer evolutionary relationships. The results of cross-validation (overall accuracy = 74.8%) demonstrated that species identification using WGM alone was not possible with a high accuracy for all eight species. While phylogenetic analyses based on the COI region could not clearly distinguish some species, the analysis based on ITS2 and TH was more useful for resolving the phylogenetic correlation of the eight species. Our results may improve Anopheles species identification strategies for effective identification and control of malaria vectors in the ROK.

Morphology of the wings and attachment apparatus in the evolution of the family Hippoboscidae (Diptera).

Using a complex analysis of the molecular genetics, morphological, and ecological characteristics of Hippoboscidae flies, the phylogenetic structure and trends in the evolution of morphological characters that contribute to the ectoparasitic lifestyle of hippoboscid flies of the north of Eurasia were studied for the first time. The research was carried out on 26 Palearctic species from 10 genera. The analysis of molecular phylogeny revealed the levels of clustering of the family with the species predominantly parasitizing mammals or birds, the time of cluster formation, and the divergence of species in the Palearctic conditions. An independent adaptation to birds occurred in the genera Icosta, Pseudolynchia, Ornithoica, and others. Bird parasites are characterized by bifid tarsal claws, long hooks on pulvilli, and long empodium setae (except genus Ornithoica). Mammalian parasites are characterized by simple tarsal claws, short lobes of hooks on pulvilli, and zones on empodium with short setae. Specialization in empodium and pulvillus morphotypes and wing reduction are higher diverged in mammalian parasites than in bird parasites. The decrease of flight ability and wing reduction independently arose in different subfamilies of Hippoboscidae flies. Our results assume that the tribe Ornithomyini is a paraphyletic group, since, according to the complex of morphological features, the genus Ornithoica can be considered a separate lineage of evolution.

The complex case of the calcareous sponge Leucosolenia complicata (Porifera: Calcarea): hidden diversity in Boreal and Arctic regions with description of a new species

Abstract In this study, we present the first integrative revision of the Boreal and Arctic calcareous sponges of the genus Leucosolenia with a specific focus on its biodiversity in the White Sea. The material for this work included a combination of newly collected specimens from different regions of the North-East Atlantic and the White Sea and historical museum collections. An integrative analysis was implemented based on vast morphological data (light microscopy, scanning and transmission electron microscopy), microbiome observations, ecological data, accompanied by molecular phylogenetic and species’ delimitation analyses based on three nuclear markers (28S rRNA, 18S rRNA, and histone 3). We demonstrate that Leucosolenia complicata, previously reported from Arctic waters, is restricted to the North-East Atlantic, while in the Arctic, Leucosolenia diversity is represented by at least four species: Leucosolenia corallorrhiza, Leucosolenia variabilis, and two new species, one of which is described herein under the name Leucosolenia creepae sp. nov.. The molecular phylogeny analysis supports the species identity of these species. In addition to conventional morphological characters, new informative fine morphological characters (skeleton and oscular crown organization; cytological structure, including morphotypes of symbiotic bacteria) were found, providing a baseline for further revision of this group in other regions.

Short Communication: Morphological, biochemical, and molecular identification of cellulolytic bacteria isolated from feces of endemic tropical herbivores

Abstract. Suharti S, Novrariani N, Wiryawan KG. 2023. Short Communication: Morphological, biochemical, and molecular identification of cellulolytic bacteria isolated from feces of endemic tropical herbivores. Biodiversitas 24: 4046-4051. Indonesia has endemic herbivores that consume lignocellulose feedstuffs including grass, tree foliage, rice straw, and legume, indicating the presence of cellulolytic bacteria in their gastrointestinal tracts. Therefore, the aim of this study was to isolate and identify cellulolytic bacteria from the feces of tropical endemic herbivores, including anoa (Bubalus depressicornis), banteng (Bos javanicus), muntjak (Muntiacus muntjak), and timor deer (Rusa timorensis). Bacteria were isolated using the serial dilution technique and screened on Carboxy Methyl Cellulose (CMC) media. The selected isolates were identified based on their morphological and biochemical characteristics, cellulase enzyme activity, and molecular identification of 16S rDNA. The result showed that a total of five bacterial isolates were isolated from feces of anoa, banteng, muntjak, and timor deer. In addition, isolates exhibited characteristics of facultative anaerobes with gram-positive coccus, fermenting glucose, fructose, sucrose, starch, and cellulose. Based on cellulolytic index, isolates from anoa and banteng feces showed high cellulolytic activity with an index of about 1.2, indicating their potential as cellulose-degrading bacteria. Molecular identification and phylogeny analysis of cellulolytic bacteria isolates from anoa and banteng feces showed 100% similarities with Enterococcus faecium. Therefore, bacteria from feces of tropical endemic herbivores, especially anoa and banteng, possess cellulolytic activity and have potential as cellulolytic probiotic for ruminants that feed on forage-based diet. This is the first study to document the cellulolytic activity of anoa, and banteng feces.

Taxonomic revision of species of the genus Kailashia based on analysis of morphological data and molecular phylogeny

Taxonomic revision of species of the genus Kailashia based on analysis of morphological data and molecular phylogeny

Thecal plate morphology, molecular phylogeny, and toxin analyses reveal two novel species of Alexandrium (Dinophyceae) and their potential for toxin production

This study describes two novel species of marine dinophytes in the genus Alexandrium. Morphological characteristics and phylogenetic analyses support the placement of the new taxa, herein designated as Alexandrium limii sp. nov. and A. ogatae sp. nov. Alexandrium limii, a species closely related to A. taylorii, is distinguished by having a shorter 2ʹ/4ʹ suture length, narrower plates 1ʹ and 6ʹʹ, with larger length: width ratios, and by the position of the ventral pore (Vp). Alexandrium ogatae is distinguishable with its metasert plate 1ʹ having almost parallel lateral margins, and by lacking a Vp. Production of paralytic shellfish toxins (PSTs), cycloimines, and goniodomins (GDs) in clonal cultures of A. ogatae, A. limii, and A. taylorii were examined analytically and the results showed that all strains contained GDs, with GDA as major variants (6–14 pg cell−1) for all strains except the Japanese strain of A. limii, which exclusively had a desmethyl variant of GDA (1.4–7.3 pg cell−1). None of the strains contained detectable levels of PSTs and cycloimines.