Revision of the Genus Cryptomonas (Cryptophyceae): a Combination of Molecular Phylogeny and Morphology Provides Insights into a Long-Hidden Dimorphism

Hoef‐Emden, Kerstin; Melkonian, Michael

doi:10.1078/143446103322454130

Cited by 119 publications

(139 citation statements)

References 52 publications

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“…This is particularly true for taxa for which classification was previously controversial due to the lack of clear morphological criteria. Successful integration of morphological and molecular taxonomy has been demonstrated for many groups of marine flagellates, for example, for cryptomonads (Hoef-Emden & Melkonian, 2003;Cerino & Zingone, 2006, 2007 and prymnesiophytes (Edvardsen et al, 2000;Medlin & Zingone, 2007;Edvardsen et al, 2011). Nevertheless, attempts to achieve such a synthesis with raphidophytes have thus far been more problematic, mainly because of the lack of correspondence between morphological and molecular classifications.…”

Section: Discussionmentioning

confidence: 99%

Phylogeny and morphology of a Chattonella (Raphidophyceae) species from the Mediterranean Sea: what is C. subsalsa?

Klöpper

John

Zingone

et al. 2013

European Journal of Phycology

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We analysed the molecular and morphological features of strains of Chattonella subsalsa isolated from the western Adriatic coast (Mediterranean Sea), with the aim of confirming their classification and elucidating their phylogenetic positions within the Raphidophyceae. We sequenced parts of the ribosomal operon, including the small subunit (SSU), the internal transcribed spacer region (ITS) and the large subunit (LSU) of the rDNA. Additionally, we analysed sequences of the chloroplast-encoded subunit psaA of Photosystem I (PSI) and rbcL, encoding the large subunit of the Rubisco gene. For three phylogenetic markers (LSU, ITS, rbcL), the sequences of the strains from the Adriatic Sea were identical and for two markers (SSU, psaA) only minor differences occurred. All strains were sister to, but well separated from, sequences from isolates in culture collections and from GenBank, thus far classified as belonging to C. subsalsa. Light and electron microscopy provided evidence for morphological differences between a strain of C. subsalsa (CCMP217) from the Gulf of Mexico and the isolates from the Adriatic Sea. Differences concerned the shape and arrangement of chloroplasts and the presence of mucocysts and other surface microstructures, which were only observed in isolates from the Adriatic Sea. This is the first evidence for two different taxa classified as C. subsalsa, which are clearly separated on the basis of several genetic markers and also show morphological differences. As compared with strains assigned to C. subsalsa from the NCMA (formerly CCMP) culture collection, the Adriatic strains more closely match the original species description. This would imply that strain CCMP217 and other genetically similar strains should be described under a new species name. Nevertheless, given the high morphological plasticity of Chattonella species, the definition of the true C. subsalsa must be decided based on detailed morphological and molecular analysis of more strains from other geographical areas.

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Section: Discussionmentioning

confidence: 99%

Phylogeny and morphology of a Chattonella (Raphidophyceae) species from the Mediterranean Sea: what is C. subsalsa?

Klöpper

John

Zingone

et al. 2013

European Journal of Phycology

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“…In another species (Proteomonas sulcata), two alternating morphologically different forms were observed, the larger one with twice as much DNA as the smaller one and hence most likely representing the diploid stage (23). Interestingly, evidence, or at least hints, for the occurrence of similar morphological dimorphism (alas without data on the ploidy level) exists for several other cryptophyte lineages, which led to the speculation that cryptophytes may exhibit an ancestral cryptic sexual dimorphic life cycle (24,25), their name thus possibly being a nice instance of "nomen est omen." A further remarkable case in point concerns two other curious algal groups in Stramenopiles.…”

Section: Sex In Eukaryotic Microorganisms: More Voyeurs Neededmentioning

confidence: 99%

Sex is a ubiquitous, ancient, and inherent attribute of eukaryotic life

Speijer

Lukeš

Eliáš

2015

Proc. Natl. Acad. Sci. U.S.A.

264

267

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Sexual reproduction and clonality in eukaryotes are mostly seen as exclusive, the latter being rather exceptional. This view might be biased by focusing almost exclusively on metazoans. We analyze and discuss reproduction in the context of extant eukaryotic diversity, paying special attention to protists. We present results of phylogenetically extended searches for homologs of two proteins functioning in cell and nuclear fusion, respectively (HAP2 and GEX1), providing indirect evidence for these processes in several eukaryotic lineages where sex has not been observed yet. We argue that (i) the debate on the relative significance of sex and clonality in eukaryotes is confounded by not appropriately distinguishing multicellular and unicellular organisms; (ii) eukaryotic sex is extremely widespread and already present in the last eukaryotic common ancestor; and (iii) the general mode of existence of eukaryotes is best described by clonally propagating cell lines with episodic sex triggered by external or internal clues. However, important questions concern the relative longevity of true clonal species (i.e., species not able to return to sexual procreation anymore). Long-lived clonal species seem strikingly rare. We analyze their properties in the light of meiotic sex development from existing prokaryotic repair mechanisms. Based on these considerations, we speculate that eukaryotic sex likely developed as a cellular survival strategy, possibly in the context of internal reactive oxygen species stress generated by a (proto) mitochondrion. Thus, in the context of the symbiogenic model of eukaryotic origin, sex might directly result from the very evolutionary mode by which eukaryotic cells arose.reactive oxygen species | evolution | protists | eukaryotes | sex

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“…Recently, molecular work (Marin et al 1998, Deane et al 2002 has shown that Cryptomonas species grouped together with species of Campylomonas and Chilomonas. Hoef-Emden and Melkonian (2003) The alignment for each gene sequence was aligned by the eye, and was edited using the Genetic Data Environment (GDE 2.4) program (Smith et al 1994). Unalignable nucleotides were excluded from phylogenetic analyses.…”

Section: Dna Isolation Polymerase Chain Reaction (Pcr) and Sequencingmentioning

confidence: 99%

“…Cryptomonas species display one or two morphotypes within a clonal culture. In the cryptomorph, the inner periplast component (IPC) is made of hexagonal to polygonal plates, whereas in the camphylomorph the IPC is a sheet-like layer (Faust 1974, Brett and Wetherbee 1986, Hill 1991, Hoef-Emden and Melkonian 2003, Hoef-Emden 2007.…”

Section: Introductionmentioning

confidence: 99%

“…Cells can be easily recognized by two unequal biflagella, olive-brownish to olive-greenish in color, large ejectisomes lined in the furrow-gullet system, and a peculiar swaying swimming behavior due to the asymmetric shape, dorsally flattened and ventrally concave in lateral view. Cells have two chloroplasts originated from red algae, which contain the accessory pigment phycoerythrin 566 of phycobiliprotein (Hill and Rowan 1989, Clay et al 1999, Deane et al 2002, Hoef-Emden and Melkonian 2003. Cryptomonas species display one or two morphotypes within a clonal culture.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Taxonomy and phylogeny of the genus Cryptomonas (Cryptophyceae, Cryptophyta) from Korea

Choi¹,

Son²,

Kim³

et al. 2013

ALGAE

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The genus Cryptomonas is easily recognized by having two flagella, green brownish color, and a swaying behavior. They have relatively simple morphology, and limited diagnostic characters, which present a major difficulty in differentiating between species of the genus. To understand species delineation and phylogenetic relationships among Cryptomonas species, the nuclear-encoded internal transcribed spacer 2 (ITS2), partial large subunit (LSU) and small subunit ribosomal DNA (rDNA), and chloroplast-encoded psbA and LSU rDNA sequences were determined and used for phylogenetic analyses, using Bayesian and maximum likelihood methods. In addition, nuclear-encoded ITS2 sequences were predicted to secondary structures, and were used to determine nine species and four unidentified species from 47 strains. Sequences of helix І, ІІ, and ІІІb in ITS2 secondary structure were very useful for the identification of Cryptomonas species. However, the helix ІV was the most variable region across species in alignment. The phylogenetic tree showed that fourteen species were monophyletic. However, some strains of C. obovata had chloroplasts with pyrenoid while others were without pyrenoid, which used as a key character in few species. Therefore, classification systems depending solely on morphological characters are inadequate, and require the use of molecular data.

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Revision of the Genus Cryptomonas (Cryptophyceae): a Combination of Molecular Phylogeny and Morphology Provides Insights into a Long-Hidden Dimorphism

Cited by 119 publications

References 52 publications

Phylogeny and morphology of a Chattonella (Raphidophyceae) species from the Mediterranean Sea: what is C. subsalsa?

Phylogeny and morphology of a Chattonella (Raphidophyceae) species from the Mediterranean Sea: what is C. subsalsa?

Sex is a ubiquitous, ancient, and inherent attribute of eukaryotic life

Taxonomy and phylogeny of the genus Cryptomonas (Cryptophyceae, Cryptophyta) from Korea

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