Coccoid Green Algae Research Articles

Valeriella persica sp. nov. (Chlorococcaceae, Chlorophyceae): A potential biodiesel feedstock from the hyperarid desert soil in Yazd (Iran) revealing new diagnostic criteria for green coccoids

Clear–cut delineation of the species identity of the drylands–inhabiting coccoid green algae is a challenging taxonomic work that requires an in–depth polyphasic investigation. Here, we employed an integrative polyphasic approach to characterize an interesting terrestrial green coccoid belonging to the recently proposed genus Valeriella from Iran. Despite morphological resemblances to some established taxa, this strain is distinguished by a combination of taxonomic features. Similarities and differences with morphologically allied taxa were discussed in detail, and some new diagnostic criteria for green coccoids were revealed. Our new findings threw light on the age-old problem in the taxonomy of green coccoids. The 18S rDNA phylogenetic assignment placed our strain in a well–supported lineage within the Valeriella clade (Chlorococcaceae, Chlorophyceae) with close affinity to V. minor. Therefore, here we propose Valeriella persica sp. nov. as a new species based on its phylogenetic position and key taxonomic features including cell-wall ultrastructure, life–cycle stages, reproduction strategies and ecology. We also assessed lipid content and fatty-acid profiles to evaluate suitability as potential feedstock for biofuel production. The lipid content and productivity were about 27 % and 130.5 mg L−1 day−1, respectively, at the late exponential phase. Gas chromatography (GC) coupled with flame−ionization detection (GC–FID) unraveled twenty−six species of FAs with highly significant levels of palmitic (C16:0; 24.74 %), oleic (C18:1c, ω–9; 19.02 %), linoleic (C18:2c, ω–6; 18.15 %), and α-linolenic (C18:3, ω–3; 16.28 %) acids. The biodiesel properties of V. persica are consistent with the international standards, making it a good candidate for biodiesel production on the large–scale. Overall, these ecophysiologically important compounds are well known to have major dynamic roles in regulating the fluidity and functioning of the cell and thylakoid membranes, and they, therefore, provide ecophysiological–adaptive traits to the extremely dry, desert habitat of this novel green coccoid.

Emended description of the genus Eremochloris (Trebouxiophyceae, Chlorophyta), with Eremochloris kamchatica sp. nov. from Kamchatka, Russia

ABSTRACT Three strains of a coccoid green alga were isolated from soil samples collected at the Shiveluch Volcano on the Kamchatka Peninsula. SSU rRNA gene sequence comparisons resolved the strains as members of the genus Eremochloris in the class Trebouxiophyceae. Analyses based on the internal transcribed spacer (ITS) rRNA secondary structure revealed that our isolates were genetically distinct from the type species of this genus. These isolates were characterized by spherical, elliptical or pyriform cells that were solitary with a single excentric nucleus. The cells harboured a single-pyrenoid parietal chloroplast, which was either simple or dissected into clear, curved or undulated lobes. Studies on the life cycle of this alga revealed that asexual reproduction takes place via autospores or biflagellated zoospores. Sexual reproduction is very scarce and is isogamous. All these features suggest a new species, which we name Eremochloris kamchatica. The description of the genus Eremochloris is emended to accommodate the features of the new species.

New Species of Chloroidium (Trebouxiophyceae, Chlorophyta) from East Asia.

Chlorella-like green algae that reproduce only asexually by immotile autospores or motile zoospores are the most typical inhabitants of non-aquatic environments. They have a simple morphology that hampers their differentiation, but algae of such habit represent a diverse array of lineages, which are mostly in the classes Chlorophyceae and Trebouxiophyceae. One of these lineages is the order Watanabeales (Watanabea clade; Trebouxiophyceae), which comprises 10 genera that share a distinct mode of reproduction through unequally sized autospores. Most of these genera account for a few species that are rarely recorded in nature. In contrast, the genus Chloroidium is one of the most species-rich and widely distributed members of the order. Three strains of coccoid green alga were isolated during a study of soil algae in the temperate monsoon climate zone of Asia. These strains are described here as a new species, Chloroidium orientalis. SSU and ITS rDNA sequence data, morphological characteristics, and life cycle features differentiate these strains from known members of the genus.

A Parachlorella kessleri (Trebouxiophyceae, Chlorophyta) strain tolerant to high concentration of calcium chloride.

Members of coccoid green algae have been documented in various extreme environments. In this article, a unicellular green alga was found to slowly grow in high concentration (3.6g/L) and pure calcium chloride solution in the laboratory. It was successfully cultured and a taxonomic study combined approaches of morphological and molecular methods was conducted to determine its classification attribution, which was followed by a preliminary physiology research to explore its unique tolerance characteristics against calcium chloride stress. The strain was identified as Parachlorella kessleri by very similar morphology and the same phylogenetic position. The morphological differences among the three species in genus Parachlorella were then discussed and the characteristic traits of absent or thin mucilaginous envelop and mantel-shaped chloroplast for P.kessleri were supported. In addition, the almost strictly spherical shape of adult cells could further distinguish the P.kessleri from the other two species. The tolerant characteristics to CaCl2 stress for this strain were confirmed and the limit concentration was revealed as between 2000 and 4000 times than the standard BG11 culture concentration. Therefore, this P.kessleri strain is expected to be a good material to explore the mechanism of resistance to calcium ions stress for eukaryotic microbiology.

Molecular Phylogeny of Unicellular Marine Coccoid Green Algae Revealed New Insights into the Systematics of the Ulvophyceae (Chlorophyta).

Most marine coccoid and sarcinoid green algal species have traditionally been placed within genera dominated by species from freshwater or soil habitats. For example, the genera Chlorocystis and Halochlorococcum contain exclusively marine species; however, their familial and ordinal affinities are unclear. They are characterized by a vegetative cell with lobated or reticulated chloroplast, formation of quadriflagellated zoospores and living epi- or endophytically within benthic macroalgae. They were integrated into the family Chlorochytriaceae which embraces all coccoid green algae with epi- or endophytic life phases. Later, they were excluded from the family of Chlorococcales based on studies of their life histories in culture, and transferred to their newly described order, Chlorocystidales of the Ulvophyceae. Both genera form a “Codiolum”-stage that serves as the unicellular sporophyte in their life cycles. Phylogenetic analyses of SSU and ITS rDNA sequences confirmed that these coccoid taxa belong to the Chlorocystidales, together with the sarcinoid genus Desmochloris. The biflagellated coccoid strains were members of the genus Sykidion, which represented its own order, Sykidiales, among the Ulvophyceae. Considering these results and the usage of the ITS-2/CBC approach revealed three species of Desmochloris, six of Chlorocystis, and three of Sykidion. Three new species and several new combinations were proposed.

Settling the identity and phylogenetic position of the psychrotolerant green algal genus Coleochlamys (Trebouxiophyceae)

ABSTRACT Despite significant recent advances, our understanding of the diversity and phylogeny of coccoid green algae remains incomplete, partly because of the existence of numerous previously described taxa that are yet to be reinvestigated to clarify their identity and phylogenetic position. An essentially forgotten taxon is the genus Coleochlamys Korshikov, presently classified in the class Chlorophyceae. Here we present the results of our investigations of one new and four previously available strains identified as Coleochlamys. Based on morphological features and molecular evidence, the strains represented two clearly differentiated species: Co. apoda, the type species of the genus, and Co. oleifera, which are both epitypified in this study. The two species differ in cell shape and presence or absence of a cell wall extension resembling a papilla. They are also differentiated by multiple compensatory base changes (CBCs) in the ITS2 region. Our data support the previous proposal that the genera Rhopalocystis and Fusochloris are later synonyms of Coleochlamys, and additionally suggest that the algae originally described as Characium perforatum K.W. Lee & H.C. Bold and Rhopalocystis cucumis are conspecific with Co. apoda. Phylogenies of both 18S rRNA and rbcL genes place Coleochlamys in the class Trebouxiophyceae, in a clade with Microthamnion. Analysis of environmental DNA data has revealed the existence of at least one additional Coleochlamys species, and of a closely related sister lineage (potentially a separate genus) encountered in an Alaskan glacier. The occurrence data on Coleochlamys indicate that the genus includes psychrotolerant algae that may be common in cold environments worldwide.

Summer phytoplankton 24-hours dynamics in the lake Svetloyar (Nizhny Novgorod region)

In this research the information of structural parameters of algocenoses (species richness, proportions of leading groups, abundance, biomass) in the photosynthetic zone of a unique karst lake Svetloyar (Nizhny Novgorod region) is provided according to the data for the summer of 2012. During the studied 24-hours period the main components of plankton were coccoid green and diatom algae, colonial and filamentous cyanobacteria, whose daily vertical migration was poorly expressed. The maximum of abundance and biomass of these species were noted at the afternoon (the period from 13:30 to 16:30) and in the most heated layer (0–4 m). Motile algae (mainly from phylum Dinophyta) were characterized with more noticeable daily activity. They were present in the algocenoses only in the daytime and evening hours and moved at night and in the morning below the photosynthetic zone. The daily dynamics of the species richness of algae demonstrated was similar with the indicators of quantitative development, while the number of dominant species remained stable during the day (amounting to 1–4 taxa in the sample).

Choricystis and Lewiniosphaera gen. nov. (Trebouxiophyceae Chlorophyta), two different green algal endosymbionts in freshwater sponges

Associations of freshwater sponges with coccoid green algae have been known for a long time. Two types of coccoid green algae, which are commonly assigned as zoochlorellae, are recognized by morphology: small coccoids (< 3 μm) without pyrenoids and larger Chlorella-like algae (4–6 μm) with pyrenoids. Despite their wide distribution in some freshwater sponges, these green algae were never studied using a combined analysis of morphology and molecular phylogeny. We investigated several endosymbiotic strains isolated from different Spongilla species, which were available in culture collections. Phylogenetic analyses of SSU and ITS rDNA sequences revealed that the strain SAG 211-40a is a member of the Chlorellaceae and represents a new species of the newly erected genus Lewiniosphaera, L symbiontica. The phylogenetic position was confirmed by morphology and ITS-2 barcode. The endosymbionts without pyrenoid were identified as Choricystis parasitica by morphology and phylogenetic analyses. The comparison with free-living strains revealed the recognition of two new Choricystis species, C. krienitzii and C. limnetica, which were confirmed by molecular signatures in V9 region of SSU rDNA and ITS-2 barcode.

Screening of Extremophile Microalgae Isolated from High Background Radiation Areas as Source of Bioactive Materials

Background: Microalgae are the source of various compounds with high potentials for being used in different industries. The production of such compounds can be raised under extreme conditions. In the present study, four cyanobacteria and one coccoid green alga were examined which were isolated from hot springs in high background radiation areas in Ramsar, a city in the north of Iran. Methods: Cadmium adsorption from aqueous solution, response towards cadmium stress, antioxidant activity, total phenolic compound and drought tolerance were investigated in these microalgae. Results: The results showed that these extremophile microalgae contain valuable biological compounds which can be useful in remediation of heavy metals from contaminated water and soils and pharmaceutical applications. The unicellular cyanobacterium, Chroococidiopsis thermalis IBRC-M50002, was the best strain with the highest biological activity in various testes such as cadmium adsorption (225 mg g-1), cadmium tolerance stress (100 mg ml-1), antioxidant activity (IC50= 18 μg mg-1) and total phenol content (100 μg ml-1). The coccoid green algae Grasiella emersonii IBRC-M50001, also exhibited significant antioxidant activity (IC50=10 μg mg-1) and total phenol compound (116 μg ml-1), but its cadmium adsorption, tolerance at cadmium stress and desiccation were lower than Chroococidiopsis thermalis. Conclusion: HBRAs microalgae, isolated from extreme conditions, are useful microorganisms for the production of bioactive substances and natural antioxidants. In other words, they exhibited high capacity to be used in pharmaceutical, industrial and commercial applications.

Micractinium tetrahymenae (Trebouxiophyceae, Chlorophyta), a New Endosymbiont Isolated from Ciliates

Endosymbiosis between coccoid green algae and ciliates are widely distributed and occur in various phylogenetic lineages among the Ciliophora. Most mixotrophic ciliates live in symbiosis with different species and genera of the so-called Chlorella clade (Trebouxiophyceae). The mixotrophic ciliates can be differentiated into two groups: (i) obligate, which always live in symbiosis with such green algae and are rarely algae-free and (ii) facultative, which formed under certain circumstances such as in anoxic environments an association with algae. A case of the facultative endosymbiosis is found in the recently described species of Tetrahymena, T. utriculariae, which lives in the bladder traps of the carnivorous aquatic plant Utricularia reflexa. The green endosymbiont of this ciliate belonged to the genus Micractinium. We characterized the isolated algal strain using an integrative approach and compared it to all described species of this genus. The phylogenetic analyses using complex evolutionary secondary structure-based models revealed that this endosymbiont represents a new species of Micractinium, M. tetrahymenae sp. nov., which was further confirmed by the ITS2/CBC approach.

Morphology and molecular phylogeny of coccoid green algae Coelastrella sensu lato (Scenedesmaceae, Sphaeropeales), including the description of three new species and two new varieties.

The genus Coelastrella was established by Chodat (Bull. Soc. Bot. Geneve, 13 [1922] 66), and was characterized as being unicellular or in few-celled aggregations with many longitudinal ribs on the cell wall. Many species of this genus showed strong ability to accumulate carotenoids and oils, so they have recently attracted much attention from researchers due to its potential applicability in the energy and food industries. In this study, a total of 23 strains of Coelastrella were sampled from China, and three new species and two new varieties were described: C. thermophila sp. nov., C. yingshanensis sp. nov., C. tenuitheca sp. nov., C. thermophila var. globulina var. nov., C. rubescens var. oocystiformis var. nov. Besides 18S rDNA and ITS2 sequences, we have newly sequenced the tufA gene marker for this taxon. Phylogenetic analysis combined with morphological studies revealed four morphotypes within the Coelastrella sensu lato clade, which contained the morphotype of original Coelastrella, original Scotiellopsis, Asterarcys, and morphotype of C. vacuolata and C. tenuitheca sp. nov. The relationships between morphological differences and phylogenic diversity based on different markers were discussed. Our results support that 18S rDNA was too conserved to be used a species-specific or even a genus-specific marker in this clade. The topology of tufA gene-based phylogenetic tree had a better match with the morphological findings.

Reevaluation and discovery of new species of the rare genus Watanabea and establishment of Massjukichlorella gen. nov. (Trebouxiophyceae, Chlorophyta) using an integrative approach.

Chlorella-like coccoid green algae are widely distributed in almost all terrestrial habitats and belong to different lineages of the Chlorophyceae and Trebouxiophyceae. The Watanabea clade of the Trebouxiophyceae shows a high genetic biodiversity. Re-investigation of the authentic strain of the rarely found W.reniformis showed several morphological differences compared to the original description. To clarify the taxonomic status of Watanabea, wecompared several new isolates with similar morphology. Phylogenetic analyses of the SSU and SSU+ITS rDNA sequences revealed that all new isolates were distinct from W.reniformis. The ITS-2/CBC approach clearly demonstrated that the strains belonging to Watanabea represented species. We emended the generic diagnosis of Watanabea, andproposed four new species. One strain, SAG 2552, represented a separate lineage that we propose as a new genus Massjukichlorella with one species M.epiphytica.

Deep genomic analysis of Coelastrella saipanensis (Scenedesmaceae, Chlorophyta): comparative chloroplast genomics of Scenedesmaceae

ABSTRACTMany species belonging to the coccoid green algae genus Coelastrella are considered potential candidates for the large-scale production of natural pigments and biofuels. However, little is known about the structural, functional and molecular aspects of the chloroplast genomes (cpDNAs) of this genus. In the present study, the complete sequence of the cpDNA of strain FACHB-2138, which was further identified as Coelastrella saipanensis Hanagata based on morphological and molecular analyses, was elucidated. The 196 140 bp cpDNA sequence that was assembled as a circular map was found to possess the typical quadripartite structure. The two identical copies of 11 897 bp inverted repeat (IR) sequences were separated from one another by single copy regions. The large single copy region (LSC) was 104 949 bp, whereas the small single copy region (SSC) was 67 397 bp. The cpDNA encoded a total of 96 unique genes, which included 67 protein-coding genes, three rRNA genes and 26 tRNA genes. A total of 19 group I introns were annotated in this genome. Comparative analyses with three species from the family Scenedesmaceae showed C. saipanensis had a slightly expanded genome, higher GC content and less skewed distribution of its genes between the two DNA strands than that of the other three species. The cpDNA data deduced from the present study helps to expand our present understanding of plant systematics and phylogenetic reconstruction, and identify the possible biotechnological applications of the species belonging to the studied taxa.

Morphology and phylogeny of three planktonic Radiococcaceae sensu lato species (Sphaeropleales, Chlorophyceae) from China, including the description of a new species Planktosphaeria hubeiensis sp. nov.

The family Radiococcaceae sensu lato, defined as colonial autospore-producing mucilaginous coccoid green algae, is widespread in terrestrial and freshwater habitats. Three species of Radiococcaceae sensu lato, including two Radiococcus species and one Planktosphaeria species, were described from China by light and electron microscopy. A new species of Planktosphaeria, Planktosphaeria hubeiensis sp. nov. was erected based on morphological comparisons and genetic analyses. Our phylogenetic analyses indicated that Radiococcaceae sensu lato is polyphyletic, and separated into three lineages. The Radiococcus species did not cluster into a monophyletic group in phylogenetic analyses; therefore the taxonomy of the genus Radiococcus should be revised in the future.

The polyphasic approach revealed new species of Chloroidium (Trebouxiophyceae, Chlorophyta)

Chlorella-like coccoid green algae are widely distributed in many types of habitats such as freshwater, terrestrial and marine. One group of terrestrial microalgae belonging to the Trebouxiophyceae forms the monophyletic lineage of the Watanabea clade. This clade exclusively comprises of ellipsoid and spherical coccoid green algae, which traditionally have been assigned as different species of Chlorella. Within this clade, seven out of ten genera are described mainly based on phylogenetic analyses of SSU and rbcL sequences. Most of the genera are represented by only one or two species that are rarely found in natural samples. In contrast, the genus Chloroidium is widely distributed across different habitats. We investigated 34 new isolates, which were originally assigned as Chloroidium or Chlorella, using an integrative approach. The phylogenetic analyses of SSU and ITS rDNA sequences revealed nine lineages, eight of which were highly supported in all of our bootstrap and Bayesian analyses. The ITS-2/CBC approach clearly demonstrated that these nine lineages represent individual species. The haplotype network analyses revealed that three out of them were widely distributed and showed no preference for any habitat. The comprehensive study of SSU and rbcL datasets also revealed that no clear synapomorphy could be found to support the assigned genus Parachloroidium. As a result of our findings, we proposed that both species belonging to Parachloroidium be transferred to Chloroidium. In addition, we re-established two species originally described by Chodat as new members of Chloroidium (C. lichenum, C. viscosum). Two of the nine lineages (C. antarcticum, C. arboriculum) were newly described in this study.

English

Conventional identification of three coccoid green algae isolates was attempted to characterize the studied algae morphologically under compound microscope, which demonstrated confusional phenomenal convergence; all were classified microscopically as the green alga Chlorella vulgaris Beijerinck, 1890. Phylogenetic studies were conducted to settle the argument about the phenotype by studying the genotype. Genotype the promising field in advance classification by using 18S rRNA and compared to GenBank database using to search the related sequences. The determined sequences showed high a similarity to the strains registered in GenBank. Phylogenetic tree of ITS within 18S RNA were analyzed: the phylogram separated into two clusters, the first cluster included C1-ITS-Iraq and C2-ITS-Iraq and put with Coelastrella Chodat, 1922 which was well supported in bootstrap tests (86-100%), while the second cluster included C3-ITS-Iraq and put with C. sorokiniana Shihira and Krauss, 1965, which have bootstrap value 100% with the mentioned species. however, in this study, the green alga Colestrella was identified as new record genus in Iraqi freshwater belonged to the order Sphaeropleales.

Novel green algal isolates from the Egyptian hyper‐arid desert oases: a polyphasic approach with a description of Pharao desertorum gen. et sp. nov. (Chlorophyceae, Chlorophyta)

The biodiversity of terrestrial algae is still grossly understudied, and African deserts in particular are barely touched in this respect. Here, four coccoid green algae from oases in the Western Desert of Egypt were characterized using a combination of morphotaxonomic, ecological and 18S rDNA data, with additional carotenoid and lipid analyses for two of the strains. Three strains were identified as affiliated with known taxa: Mychonastes sp., Asterarcys sp. (first report of this genus from a desert soil), and Stichococcus cf. deasonii. The fourth strain is proposed to represent a new cryptic genus Pharao gen. nov., with the type species P.desertorum sp. nov. The new taxon is sister to the clade of uncharacterized North American desert strains of Radiococcaceae (Chlorophyceae, Chlorophyta). The pigment profile of P.desertorum gen. et sp. nov. revealed carotenoids and chlorophylls typical of green algae. Bioorganic analysis showed a complex lipidome based on phospho- (PC), galacto- (MGDG and DGDG), betaine- (DGTS), and sulfoquinovosyl- (SQDG) membrane lipids, besides significant amounts of storage neutral lipids such as diacyl- (DAG) and triacylglycerols (TAG). The presence of saturated alkyl chains within all the membrane lipid classes in P.desertorum and Asterarcys sp. appears to reflect the need to maintain membrane fluidity and viscosity. In summary, African deserts likely still harbor new taxa to be described, and lipidomic analyses of such taxa may provide clues about their ability to survive in the extremely harsh desert habitats.

Cell Wall Structure of Coccoid Green Algae as an Important Trade-Off Between Biotic Interference Mechanisms and Multidimensional Cell Growth

Coccoid green algae can be divided in two groups based on their cell wall structure. One group has a highly chemical resistant cell wall (HR-cell wall) containing algaenan. The other group is more susceptible to chemicals (LR-cell wall – Low resistant cell wall). Algaenan is considered as important molecule to explain cell wall resistance. Interestingly, cell wall types (LR- and HR-cell wall) are not in accordance with the taxonomic classes Chlorophyceae and Trebouxiophyceae, which makes it even more interesting to consider the ecological function. It was already shown that algaenan helps to protect against virus, bacterial and fungal attack, but in this study we show for the first time that green algae with different cell wall properties show different sensitivity against interference competition with the cyanobacterium Microcystis aeruginosa. Based on previous work with co-cultures of M. aeruginosa and two green algae (Acutodesmus obliquus and Oocystis marssonii) differing in their cell wall structure, it was shown that M. aeruginosa could impair only the growth of the green algae if they belong to the LR-cell wall type. In this study it was shown that the sensitivity to biotic interference mechanism shows a more general pattern within coccoid green algae species depending on cell wall structure.

Jenufa lobulosa sp. nov. (Chlorophyceae, Chlorophyta), a new epilithic, terrestrial species described from China

:Unicellular coccoid green algae are characterised by a high cryptic diversity, but such diversity is still poorly known, especially in terrestrial environments. The genus Jenufa, first described in 2011 from terrestrial habitats, currently includes three species: J. perforata, J. minuta and J. aeroterrestrica. We describe a new species, Jenufa lobulosa sp. nov. The type strain FACHB-2128 was isolated from sandstone surfaces in Nanning, Guangxi Province, a subtropical area in southwestern China, and the cultured material was examined using light and electron microscopy. It shared representative features of the genus: a parietal perforated chloroplast with several lobes, no pyrenoids, and asexual reproduction via autospores. However, J. lobulosa differed from congeners in the mean size of its vegetative cells and autosporangia, the number of autospores and cell wall thickness. Phylogenetic analyses of 18S rDNA and rbcL sequences showed that strain FACHB-2128 belonged to the Jenufa clade of the Chlorophyceae, forming an independent lineage and differing from any known species. The position of strain FACHB-2128 within Jenufa was also supported by ITS2 rDNA sequences.

Occurrence and characterization of an epibiotic parasite in cultures of oleaginous microalga Graesiella sp. WBG-1

Mass culture of oleaginous microalgae in open raceway ponds is considered to be the cost-effective method for biodiesel production. The oleaginous green alga Graesiella sp. WBG-1 is an industrial strain capable of high lipid productivity, but it is subject to parasitism. In the present study, an epibiotic parasite EPG01 was found in cultures of the oleaginous Graesiella sp. WBG-1 and had devastating effects on microalgal growth and lipid accumulation in open raceway ponds. Based on analyses of the morphology, ultrastructure, 18S rDNA-based phylogeny, and host specificity, the parasite EPG01 was identified as Rhizophydium scenedesmi. Moreover, the host specificity test showed that only three coccoid green algae strains were rapidly and intensively infected by the parasite EPG01: Chlorococcum sp. A213, Chlorococcum sp. GP1, and Graesiella sp. WBG-1. This is the first documented report of R. scenedesmi infection in oleaginous coccoid green algae. This present study verified the presence of haustorium and the thick-walled resting sporangium and also proposed a life cycle description for R. scenedesmi. Our results will improve understanding of parasite-host relationships and help to establish strategies for the control of parasitic contaminations.