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Lindsey CR, Knoll AH, Herron MD, Rosenzweig F. Fossil-calibrated molecular clock data enable reconstruction of steps leading to differentiated multicellularity and anisogamy in the Volvocine algae. BMC Biol 2024; 22:79. [PMID: 38600528 PMCID: PMC11007952 DOI: 10.1186/s12915-024-01878-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 04/03/2024] [Indexed: 04/12/2024] Open
Abstract
BACKGROUND Throughout its nearly four-billion-year history, life has undergone evolutionary transitions in which simpler subunits have become integrated to form a more complex whole. Many of these transitions opened the door to innovations that resulted in increased biodiversity and/or organismal efficiency. The evolution of multicellularity from unicellular forms represents one such transition, one that paved the way for cellular differentiation, including differentiation of male and female gametes. A useful model for studying the evolution of multicellularity and cellular differentiation is the volvocine algae, a clade of freshwater green algae whose members range from unicellular to colonial, from undifferentiated to completely differentiated, and whose gamete types can be isogamous, anisogamous, or oogamous. To better understand how multicellularity, differentiation, and gametes evolved in this group, we used comparative genomics and fossil data to establish a geologically calibrated roadmap of when these innovations occurred. RESULTS Our ancestral-state reconstructions, show that multicellularity arose independently twice in the volvocine algae. Our chronograms indicate multicellularity evolved during the Carboniferous-Triassic periods in Goniaceae + Volvocaceae, and possibly as early as the Cretaceous in Tetrabaenaceae. Using divergence time estimates we inferred when, and in what order, specific developmental changes occurred that led to differentiated multicellularity and oogamy. We find that in the volvocine algae the temporal sequence of developmental changes leading to differentiated multicellularity is much as proposed by David Kirk, and that multicellularity is correlated with the acquisition of anisogamy and oogamy. Lastly, morphological, molecular, and divergence time data suggest the possibility of cryptic species in Tetrabaenaceae. CONCLUSIONS Large molecular datasets and robust phylogenetic methods are bringing the evolutionary history of the volvocine algae more sharply into focus. Mounting evidence suggests that extant species in this group are the result of two independent origins of multicellularity and multiple independent origins of cell differentiation. Also, the origin of the Tetrabaenaceae-Goniaceae-Volvocaceae clade may be much older than previously thought. Finally, the possibility of cryptic species in the Tetrabaenaceae provides an exciting opportunity to study the recent divergence of lineages adapted to live in very different thermal environments.
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Affiliation(s)
- Charles Ross Lindsey
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Andrew H Knoll
- Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford St., Cambridge, MA, 02138, USA
| | - Matthew D Herron
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Frank Rosenzweig
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
- Parker H. Petit Institute for Bioengineering and Biosciences, Atlanta, GA, 30332, USA.
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2
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Harvey THP. Colonial green algae in the Cambrian plankton. Proc Biol Sci 2023; 290:20231882. [PMID: 37876191 PMCID: PMC10598416 DOI: 10.1098/rspb.2023.1882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Accepted: 09/28/2023] [Indexed: 10/26/2023] Open
Abstract
The fossil record indicates a major turnover in marine phytoplankton across the Ediacaran-Cambrian transition, coincident with the rise of animal-rich ecosystems. However, the diversity, affinities and ecologies of Cambrian phytoplankton are poorly understood, leaving unclear the role of animal interactions and the drivers of diversification. New exceptionally preserved acritarchs (problematic organic-walled microfossils) from the late early Cambrian (around 510 Ma) reveal colonial organization characterized by rings and plates of interconnected, geometrically arranged cells. The assemblage exhibits a wide but gradational variation in cell size, ornamentation and intercell connection, interpreted as representing one or more species with determinate (coenobial) colony formation via cell division, aggregation and growth by cell expansion. An equivalent strategy is known only among green algae, specifically chlorophycean chlorophytes. The fossils differ in detail from modern freshwater examples and apparently represent an earlier convergent radiation in marine settings. Known trade-offs between sinking risk and predator avoidance in colonial phytoplankton point to adaptations triggered by intensifying grazing pressure during a Cambrian metazoan invasion of the water column. The new fossils reveal that not all small acritarchs are unicellular resting cysts, and support an early Palaeozoic prominence of green algal phytoplankton as predicted by molecular biomarkers.
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Affiliation(s)
- Thomas H. P. Harvey
- Centre for Palaeobiology and Biosphere Evolution, School of Geography, Geology and the Environment, University of Leicester, University Road, Leicester LE1 7RH, UK
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3
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Ma X, Shi X, Wang Q, Zhao M, Zhang Z, Zhong B. A Reinvestigation of Multiple Independent Evolution and Triassic-Jurassic Origins of Multicellular Volvocine Algae. Genome Biol Evol 2023; 15:evad142. [PMID: 37498572 PMCID: PMC10410301 DOI: 10.1093/gbe/evad142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 07/09/2023] [Accepted: 07/22/2023] [Indexed: 07/28/2023] Open
Abstract
The evolution of multicellular organisms is considered to be a major evolutionary transition, profoundly affecting the ecology and evolution of nearly all life on earth. The volvocine algae, a unique clade of chlorophytes with diverse cell morphology, provide an appealing model for investigating the evolution of multicellularity and development. However, the phylogenetic relationship and timescale of the volvocine algae are not fully resolved. Here, we use extensive taxon and gene sampling to reconstruct the phylogeny of the volvocine algae. Our results support that the colonial volvocine algae are not monophyletic group and multicellularity independently evolve at least twice in the volvocine algae, once in Tetrabaenaceae and another in the Goniaceae + Volvocaceae. The simulation analyses suggest that incomplete lineage sorting is a major factor for the tree topology discrepancy, which imply that the multispecies coalescent model better fits the data used in this study. The coalescent-based species tree supports that the Goniaceae is monophyletic and Crucicarteria is the earliest diverging lineage, followed by Hafniomonas and Radicarteria within the Volvocales. By considering the multiple uncertainties in divergence time estimation, the dating analyses indicate that the volvocine algae occurred during the Cryogenian to Ediacaran (696.6-551.1 Ma) and multicellularity in the volvocine algae originated from the Triassic to Jurassic. Our phylogeny and timeline provide an evolutionary framework for studying the evolution of key traits and the origin of multicellularity in the volvocine algae.
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Affiliation(s)
- Xiaoya Ma
- College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Xuan Shi
- College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Qiuping Wang
- College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Mengru Zhao
- College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Zhenhua Zhang
- College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Bojian Zhong
- College of Life Sciences, Nanjing Normal University, Nanjing, China
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4
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von der Heyde B, von der Heyde EL, Hallmann A. Cell Type-Specific Promoters of Volvox carteri for Molecular Cell Biology Studies. Genes (Basel) 2023; 14:1389. [PMID: 37510294 PMCID: PMC10379329 DOI: 10.3390/genes14071389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 06/26/2023] [Indexed: 07/30/2023] Open
Abstract
The multicellular green alga Volvox carteri has emerged as a valuable model organism for investigating various aspects of multicellularity and cellular differentiation, photoreception and phototaxis, cell division, biogenesis of the extracellular matrix and morphogenetic movements. While a range of molecular tools and bioinformatics resources have been made available for exploring these topics, the establishment of cell type-specific promoters in V. carteri has not been achieved so far. Therefore, here, we conducted a thorough screening of transcriptome data from RNA sequencing analyses of V. carteri in order to identify potential cell type-specific promoters. Eventually, we chose two putative strong and cell type-specific promoters, with one exhibiting specific expression in reproductive cells (gonidia), the PCY1 promoter, and the other in somatic cells, the PFP promoter. After cloning both promoter regions, they were introduced upstream of a luciferase reporter gene. By using particle bombardment, the DNA constructs were stably integrated into the genome of V. carteri. The results of the expression analyses, which were conducted at both the transcript and protein levels, demonstrated that the two promoters drive cell type-specific expression in their respective target cell types. Transformants with considerably diverse expression levels of the chimeric genes were identifiable. In conclusion, the screening and analysis of transcriptome data from RNA sequencing allowed for the identification of potential cell type-specific promoters in V. carteri. Reporter gene constructs demonstrated the actual usability of two promoters. The investigated PCY1 and PFP promoters were proven to be potent molecular tools for genetic engineering in V. carteri.
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Affiliation(s)
- Benjamin von der Heyde
- Department of Cellular and Developmental Biology of Plants, University of Bielefeld, Universitätsstr. 25, 33615 Bielefeld, Germany
| | - Eva Laura von der Heyde
- Department of Cellular and Developmental Biology of Plants, University of Bielefeld, Universitätsstr. 25, 33615 Bielefeld, Germany
| | - Armin Hallmann
- Department of Cellular and Developmental Biology of Plants, University of Bielefeld, Universitätsstr. 25, 33615 Bielefeld, Germany
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5
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Takahashi K, Suzuki S, Kawai-Toyooka H, Yamamoto K, Hamaji T, Ootsuki R, Yamaguchi H, Kawachi M, Higashiyama T, Nozaki H. Reorganization of the ancestral sex-determining regions during the evolution of trioecy in Pleodorina starrii. Commun Biol 2023; 6:590. [PMID: 37296191 PMCID: PMC10256686 DOI: 10.1038/s42003-023-04949-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 05/17/2023] [Indexed: 06/12/2023] Open
Abstract
The coexistence of three sexual phenotypes (male, female and bisexual) in a single species, 'trioecy', is rarely found in diploid organisms such as flowering plants and invertebrates. However, trioecy in haploid organisms has only recently been reported in a green algal species, Pleodorina starrii. Here, we generated whole-genome data of the three sex phenotypes of P. starrii to reveal a reorganization of the ancestral sex-determining regions (SDRs) in the sex chromosomes: the male and bisexual phenotypes had the same "male SDR" with paralogous gene expansions of the male-determining gene MID, whereas the female phenotype had a "female SDR" with transposition of the female-specific gene FUS1 to autosomal regions. Although the male and bisexual sex phenotypes had the identical male SDR and harbored autosomal FUS1, MID and FUS1 expression during sexual reproduction differed between them. Thus, the coexistence of three sex phenotypes in P. starrii is possible.
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Affiliation(s)
- Kohei Takahashi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Shigekatsu Suzuki
- Biodiversity Division, National Institute for Environmental Studies, Onogawa, Tsukuba, Ibaraki, 305-8506, Japan
| | - Hiroko Kawai-Toyooka
- Department of Frontier Bioscience, Hosei University, Kajino-cho, Koganei, Tokyo, 184-8584, Japan
| | - Kayoko Yamamoto
- Department of Chemical and Biological Sciences, Faculty of Science, Japan Women's University, Bunkyo-ku, Tokyo, 112-8681, Japan
| | - Takashi Hamaji
- Research and Development Initiative, Chuo University, Kasuga, Bunkyo-ku, Tokyo, 112-8551, Japan
| | - Ryo Ootsuki
- Department of Chemical and Biological Sciences, Faculty of Science, Japan Women's University, Bunkyo-ku, Tokyo, 112-8681, Japan
- Department of Natural Sciences, Faculty of Arts and Sciences, Komazawa University, Komazawa, Setagaya-ku, Tokyo, 154-8525, Japan
| | - Haruyo Yamaguchi
- Biodiversity Division, National Institute for Environmental Studies, Onogawa, Tsukuba, Ibaraki, 305-8506, Japan
| | - Masanobu Kawachi
- Biodiversity Division, National Institute for Environmental Studies, Onogawa, Tsukuba, Ibaraki, 305-8506, Japan
| | - Tetsuya Higashiyama
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Hisayoshi Nozaki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
- Biodiversity Division, National Institute for Environmental Studies, Onogawa, Tsukuba, Ibaraki, 305-8506, Japan.
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Grochau-Wright ZI, Nedelcu AM, Michod RE. The Genetics of Fitness Reorganization during the Transition to Multicellularity: The Volvocine regA-like Family as a Model. Genes (Basel) 2023; 14:genes14040941. [PMID: 37107699 PMCID: PMC10137558 DOI: 10.3390/genes14040941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 04/06/2023] [Accepted: 04/13/2023] [Indexed: 04/29/2023] Open
Abstract
The evolutionary transition from single-celled to multicellular individuality requires organismal fitness to shift from the cell level to a cell group. This reorganization of fitness occurs by re-allocating the two components of fitness, survival and reproduction, between two specialized cell types in the multicellular group: soma and germ, respectively. How does the genetic basis for such fitness reorganization evolve? One possible mechanism is the co-option of life history genes present in the unicellular ancestors of a multicellular lineage. For instance, single-celled organisms must regulate their investment in survival and reproduction in response to environmental changes, particularly decreasing reproduction to ensure survival under stress. Such stress response life history genes can provide the genetic basis for the evolution of cellular differentiation in multicellular lineages. The regA-like gene family in the volvocine green algal lineage provides an excellent model system to study how this co-option can occur. We discuss the origin and evolution of the volvocine regA-like gene family, including regA-the gene that controls somatic cell development in the model organism Volvox carteri. We hypothesize that the co-option of life history trade-off genes is a general mechanism involved in the transition to multicellular individuality, making volvocine algae and the regA-like family a useful template for similar investigations in other lineages.
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Affiliation(s)
| | - Aurora M Nedelcu
- Biology Department, University of New Brunswick, Fredericton, NB E3B 5A3, Canada
| | - Richard E Michod
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA
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7
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Jiménez-Marín B, Rakijas JB, Tyagi A, Pandey A, Hanschen ER, Anderson J, Heffel MG, Platt TG, Olson BJSC. Gene loss during a transition to multicellularity. Sci Rep 2023; 13:5268. [PMID: 37002250 PMCID: PMC10066295 DOI: 10.1038/s41598-023-29742-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 02/09/2023] [Indexed: 04/03/2023] Open
Abstract
Multicellular evolution is a major transition associated with momentous diversification of multiple lineages and increased developmental complexity. The volvocine algae comprise a valuable system for the study of this transition, as they span from unicellular to undifferentiated and differentiated multicellular morphologies despite their genomes being similar, suggesting multicellular evolution requires few genetic changes to undergo dramatic shifts in developmental complexity. Here, the evolutionary dynamics of six volvocine genomes were examined, where a gradual loss of genes was observed in parallel to the co-option of a few key genes. Protein complexes in the six species exhibited novel interactions, suggesting that gene loss could play a role in evolutionary novelty. This finding was supported by gene network modeling, where gene loss outpaces gene gain in generating novel stable network states. These results suggest gene loss, in addition to gene gain and co-option, may be important for the evolution developmental complexity.
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Affiliation(s)
- Berenice Jiménez-Marín
- Division of Biology, Kansas State University, Manhattan, KS, 66506, USA
- Interdepartmental Genetics Graduate Program, Kansas State University, Manhattan, KS, 66506, USA
| | - Jessica B Rakijas
- Division of Biology, Kansas State University, Manhattan, KS, 66506, USA
| | - Antariksh Tyagi
- Division of Biology, Kansas State University, Manhattan, KS, 66506, USA
| | - Aakash Pandey
- Division of Biology, Kansas State University, Manhattan, KS, 66506, USA
| | | | - Jaden Anderson
- Division of Biology, Kansas State University, Manhattan, KS, 66506, USA
| | - Matthew G Heffel
- Division of Biology, Kansas State University, Manhattan, KS, 66506, USA
- Interdepartmental Genetics Graduate Program, Kansas State University, Manhattan, KS, 66506, USA
| | - Thomas G Platt
- Division of Biology, Kansas State University, Manhattan, KS, 66506, USA
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8
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Ford SA, Craig RJ, Ness RW. A novel method for identifying Chlamydomonas reinhardtii (Chlorophyta) and closely related species from nature. JOURNAL OF PHYCOLOGY 2023; 59:281-288. [PMID: 36453860 DOI: 10.1111/jpy.13306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 11/14/2022] [Indexed: 06/17/2023]
Abstract
Here, we introduce a new method for efficiently sampling Chlamydomonas reinhardtii and closely related species using a colony PCR-based screen with novel primer sets designed to specifically detect these important model microalgae. To demonstrate the utility of our new method, we collected 130 soil samples from a wide range of habitats in Ontario, Canada and identified 33 candidate algae, which were barcoded by sequencing a region of the rbcL plastid gene. For select isolates, 18S rRNA gene and YPT4 nuclear markers were also sequenced. Based on phylogenetic and haplotype network analyses of these three loci, seven novel isolates were identified as C. reinhardtii, and one additional isolate appeared to be more closely related to C. reinhardtii than any other known species. All seven new C. reinhardtii strains were interfertile with previously collected C. reinhardtii field isolates, validating the effectiveness of our molecular screen.
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Affiliation(s)
- Scott A Ford
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, Ontario, L5L 1C6, Canada
- Department of Cell & Systems Biology, University of Toronto, 25 Harbord Street, Toronto, Ontario, M5S 3G5, Canada
| | - Rory J Craig
- California Institute for Quantitative Biosciences, University of California, Berkeley, 174 Stanley Hall, Berkeley, California, 94720-3220, USA
| | - Rob W Ness
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, Ontario, L5L 1C6, Canada
- Department of Cell & Systems Biology, University of Toronto, 25 Harbord Street, Toronto, Ontario, M5S 3G5, Canada
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario, M5S 3B2, Canada
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9
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Hu Y, Zhang J, Huang J, Zhou M, Hu S. The biogeography of colonial volvocine algae in the Yangtze River basin. Front Microbiol 2023; 14:1078081. [PMID: 36778887 PMCID: PMC9910701 DOI: 10.3389/fmicb.2023.1078081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 01/12/2023] [Indexed: 01/27/2023] Open
Abstract
Colonial Volvocine Algae (CVA) are of great significance for biological evolution study, but little is presently known about their biogeographic distribution. Meanwhile, with the impact of climate change and human activities, their effects on the distribution and structures of CVA communities also remain largely unknown. Herein, the biogeography of CVA was investigated in the Yangtze River basin, 172 sampling sites were set up within a catchment area of 1,800,000 km2, and the distribution and community composition of CVA were studied using single-molecule real-time sequencing and metabarcoding technology based on the full-length 18S sequence. In 76 sampling sites, CVA was discovered in two families, eight genera, and nine species. Eudorina and Colemanosphaera were the main dominant genus. Based on the result of the random forest model and Eta-squared value, the distribution of CVA was significantly influenced by water temperature, altitude, and TP. CVA could be suitably distributed at an average water temperature of 22°C, an average TP concentration of 0.06 mg/L, and an altitude lower than 3,920 m. To assess the effects of anthropogenic pollution on the structures and co-occurrence patterns of CVA communities, we used a stress index calculated by 10 environmental factors to divide the CVA community into low and high pollution group. Network analysis showed that greater pollution levels would have a negative impact on the co-occurrence patterns and diversity of the CVA community. Finally, to study the scientific distribution of CVA under current and future climate change scenarios, we analyzed the climate suitability regionalization of CVA with the maximum entropy model based on 19 climatic factors and four climate scenarios from 2021 to 2040 published by CMIP6. Our results reveal the suitable areas of CVA, and temperature is an important environmental factor affecting the distribution of CVA. With the change of climate in the future, the Three Gorges Reservoir Area, Chaohu Lake, and Taihu Lake are still highly suitable areas for CVA, but the habitat of CVA may be fragmented, and more thorough temporal surveys and sampling of the sediment or mud are needed to investigate the fragmentation of CVA.
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Nozaki H, Mori F, Tanaka Y, Matsuzaki R, Yamashita S, Yamaguchi H, Kawachi M. Cryopreservation of two species of the multicellular volvocine green algal genus Astrephomene. BMC Microbiol 2023; 23:16. [PMID: 36650459 PMCID: PMC9847204 DOI: 10.1186/s12866-023-02767-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 01/10/2023] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND Astrephomene is an interesting green algal genus that, together with Volvox, shows convergent evolution of spheroidal multicellular bodies with somatic cells of the colonial or multicellular volvocine lineage. A recent whole-genome analysis of A. gubernaculifera resolved the molecular-genetic basis of such convergent evolution, and two species of Astrephomene were described. However, maintenance of culture strains of Astrephomene requires rapid inoculation of living cultures, and cryopreserved culture strains have not been established in public culture collections. RESULTS To establish cryopreserved culture strains of two species of Astrephomene, conditions for cryopreservation of the two species were investigated using immature and mature vegetative colonies and two cryoprotectants: N,N-dimethylformamide (DMF) and hydroxyacetone (HA). Rates of cell survival of the A. gubernaculifera or A. perforata strain after two-step cooling and freezing in liquid nitrogen were compared between different concentrations (3 and 6%) of DMF and HA and two types of colonies: immature colonies (small colonies newly released from the parent) and mature colonies (large colonies just before daughter colony formation). The highest rate of survival [11 ± 13% (0.36-33%) by the most probable number (MPN) method] of A. gubernaculifera strain NIES-4017 (established in 2014) was obtained when culture samples of immature colonies were subjected to cryogenic treatment with 6% DMF. In contrast, culture samples of mature colonies subjected to 3% HA cryogenic treatment showed the highest "MPN survival" [5.5 ± 5.9% (0.12-12%)] in A. perforata. Using the optimized cryopreservation conditions for each species, survival after freezing in liquid nitrogen was examined for six other strains of A. gubernaculifera (established from 1962 to 1981) and another A. perforata strain maintained in the Microbial Culture Collection at the National Institute for Environmental Studies (MCC-NIES). We obtained ≥0.1% MPN survival of the A. perforata strain. However, only two of the six strains of A. gubernaculifera showed ≥0.1% MPN survival. By using the optimal cryopreserved conditions obtained for each species, five cryopreserved strains of two species of Astrephomene were established and deposited in the MCC-NIES. CONCLUSIONS The optimal cryopreservation conditions differed between the two species of Astrephomene. Cryopreservation of long-term-maintained strains of A. gubernaculifera may be difficult; further studies of cryopreservation of these strains are needed.
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Affiliation(s)
- Hisayoshi Nozaki
- grid.140139.e0000 0001 0746 5933Biodiversity Division, National Institute for Environmental Studies, Tsukuba, Ibaraki 305-8506 Japan ,grid.26999.3d0000 0001 2151 536XDepartment of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, 113-0033 Japan
| | - Fumi Mori
- grid.140139.e0000 0001 0746 5933Biodiversity Division, National Institute for Environmental Studies, Tsukuba, Ibaraki 305-8506 Japan
| | - Yoko Tanaka
- grid.140139.e0000 0001 0746 5933Biodiversity Division, National Institute for Environmental Studies, Tsukuba, Ibaraki 305-8506 Japan
| | - Ryo Matsuzaki
- grid.140139.e0000 0001 0746 5933Biodiversity Division, National Institute for Environmental Studies, Tsukuba, Ibaraki 305-8506 Japan
| | - Shota Yamashita
- grid.26999.3d0000 0001 2151 536XDepartment of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, 113-0033 Japan ,grid.288127.60000 0004 0466 9350Present Address: Department of Gene Function and Phenomics, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka 411-8540 Japan
| | - Haruyo Yamaguchi
- grid.140139.e0000 0001 0746 5933Biodiversity Division, National Institute for Environmental Studies, Tsukuba, Ibaraki 305-8506 Japan
| | - Masanobu Kawachi
- grid.140139.e0000 0001 0746 5933Biodiversity Division, National Institute for Environmental Studies, Tsukuba, Ibaraki 305-8506 Japan
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11
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Nozaki H, Mori F, Tanaka Y, Matsuzaki R, Yamaguchi H, Kawachi M. Cryopreservation of vegetative cells and zygotes of the multicellular volvocine green alga Gonium pectorale. BMC Microbiol 2022; 22:103. [PMID: 35421922 PMCID: PMC9008917 DOI: 10.1186/s12866-022-02519-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Accepted: 03/30/2022] [Indexed: 11/17/2022] Open
Abstract
Background Colonial and multicellular volvocine green algae have been extensively studied recently in various fields of the biological sciences. However, only one species (Pandorina morum) has been cryopreserved in public culture collections. Results Here, we investigated conditions for cryopreservation of the multicellular volvocine alga Gonium pectorale using vegetative colonies or cells and zygotes. Rates of vegetative cell survival in a G. pectorale strain after two-step cooling and freezing in liquid nitrogen were compared between different concentrations (3% and 6%) of the cryoprotectant N,N-dimethylformamide (DMF) and two types of tubes (0.2-mL polymerase chain reaction tubes and 2-mL cryotubes) used for cryopreservation. Among the four conditions investigated, the highest rate of survival [2.7 ± 3.6% (0.54–10%) by the most probable number (MPN) method] was obtained when 2.0-mL cryotubes containing 1.0 mL of culture samples with 6% DMF were subjected to cryogenic treatment. Using these optimized cryopreservation conditions, survival rates after freezing in liquid nitrogen were examined for twelve other strains of G. pectorale and twelve strains of five other Gonium species. We obtained ≥ 0.1% MPN survival in nine of the twelve G. pectorale strains tested. However, < 0.1% MPN survival was detected in eleven of twelve strains of five other Gonium species. In total, ten cryopreserved strains of G. pectorale were newly established in the Microbial Culture Collection at the National Institute for Environmental Studies. Although the cryopreservation of zygotes of volvocine algae has not been previously reported, high rates (approximately 60%) of G. pectorale zygote germination were observed after thawing zygotes that had been cryopreserved with 5% or 10% methanol as the cryoprotectant during two-step cooling and freezing in liquid nitrogen. Conclusions The present study demonstrated that cryopreservation of G. pectorale is possible with 6% DMF as a cryoprotectant and 1.0-mL culture samples in 2.0-mL cryotubes subjected to two-step cooling in a programmable freezer. Supplementary Information The online version contains supplementary material available at 10.1186/s12866-022-02519-9.
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Jiménez-Marín B, Olson BJSC. The Curious Case of Multicellularity in the Volvocine Algae. Front Genet 2022; 13:787665. [PMID: 35295942 PMCID: PMC8919427 DOI: 10.3389/fgene.2022.787665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 01/20/2022] [Indexed: 11/13/2022] Open
Abstract
The evolution of multicellularity is a major evolutionary transition that underlies the radiation of many species in all domains of life, especially in eukaryotes. The volvocine green algae are an unconventional model system that holds great promise in the field given its genetic tractability, late transition to multicellularity, and phenotypic diversity. Multiple efforts at linking multicellularity-related developmental landmarks to key molecular changes, especially at the genome level, have provided key insights into the molecular innovations or lack thereof that underlie multicellularity. Twelve developmental changes have been proposed to explain the evolution of complex differentiated multicellularity in the volvocine algae. Co-option of key genes, such as cell cycle and developmental regulators has been observed, but with few exceptions, known co-option events do not seem to coincide with most developmental features observed in multicellular volvocines. The apparent lack of “master multicellularity genes” combined with no apparent correlation between gene gains for developmental processes suggest the possibility that many multicellular traits might be the product gene-regulatory and functional innovations; in other words, multicellularity can arise from shared genomic repertoires that undergo regulatory and functional overhauls.
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Affiliation(s)
- Berenice Jiménez-Marín
- Division of Biology, Kansas State University, Manhattan, KS, United States.,Interdepartmental Genetics Graduate Program, Kansas State University, Manhattan, KS, United States
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Genome sequencing of the multicellular alga Astrephomene provides insights into convergent evolution of germ-soma differentiation. Sci Rep 2021; 11:22231. [PMID: 34811380 PMCID: PMC8608804 DOI: 10.1038/s41598-021-01521-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 10/29/2021] [Indexed: 01/27/2023] Open
Abstract
Germ-soma differentiation evolved independently in many eukaryotic lineages and contributed to complex multicellular organizations. However, the molecular genetic bases of such convergent evolution remain unresolved. Two multicellular volvocine green algae, Volvox and Astrephomene, exhibit convergent evolution of germ-soma differentiation. The complete genome sequence is now available for Volvox, while genome information is scarce for Astrephomene. Here, we generated the de novo whole genome sequence of Astrephomene gubernaculifera and conducted RNA-seq analysis of isolated somatic and reproductive cells. In Volvox, tandem duplication and neofunctionalization of the ancestral transcription factor gene (RLS1/rlsD) might have led to the evolution of regA, the master regulator for Volvox germ-soma differentiation. However, our genome data demonstrated that Astrephomene has not undergone tandem duplication of the RLS1/rlsD homolog or acquisition of a regA-like gene. Our RNA-seq analysis revealed the downregulation of photosynthetic and anabolic gene expression in Astrephomene somatic cells, as in Volvox. Among genes with high expression in somatic cells of Astrephomene, we identified three genes encoding putative transcription factors, which may regulate somatic cell differentiation. Thus, the convergent evolution of germ-soma differentiation in the volvocine algae may have occurred by the acquisition of different regulatory circuits that generate a similar division of labor.
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