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Khan AK, Kausar H, Jaferi SS, Drouet S, Hano C, Abbasi BH, Anjum S. An Insight into the Algal Evolution and Genomics. Biomolecules 2020; 10:E1524. [PMID: 33172219 PMCID: PMC7694994 DOI: 10.3390/biom10111524] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 11/02/2020] [Accepted: 11/05/2020] [Indexed: 01/06/2023] Open
Abstract
With the increase in biotechnological, environmental, and nutraceutical importance of algae, about 100 whole genomic sequences of algae have been published, and this figure is expected to double in the coming years. The phenotypic and ecological diversity among algae hints at the range of functional capabilities encoded by algal genomes. In order to explore the biodiversity of algae and fully exploit their commercial potential, understanding their evolutionary, structural, functional, and developmental aspects at genomic level is a pre-requisite. So forth, the algal genomic analysis revealed us that algae evolved through endosymbiotic gene transfer, giving rise to around eight phyla. Amongst the diverse algal species, the unicellular green algae Chlamydomonas reinhardtii has attained the status of model organism as it is an ideal organism to elucidate the biological processes critical to plants and animals, as well as commercialized to produce range of bio-products. For this review, an overview of evolutionary process of algae through endosymbiosis in the light of genomics, as well as the phylogenomic, studies supporting the evolutionary process of algae was reviewed. Algal genomics not only helped us to understand the evolutionary history of algae but also may have an impact on our future by helping to create algae-based products and future biotechnological approaches.
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Affiliation(s)
- Amna Komal Khan
- Department of Biotechnology, Kinnaird College for Women, Lahore 54000, Pakistan; (A.K.K.); (H.K.); (S.S.J.)
| | - Humera Kausar
- Department of Biotechnology, Kinnaird College for Women, Lahore 54000, Pakistan; (A.K.K.); (H.K.); (S.S.J.)
| | - Syyada Samra Jaferi
- Department of Biotechnology, Kinnaird College for Women, Lahore 54000, Pakistan; (A.K.K.); (H.K.); (S.S.J.)
| | - Samantha Drouet
- Laboratoire de Biologie des Ligneux et des Grandes Cultures (LBLGC), INRAE USC1328, Université d’Orléans, 28000 Chartres, France; (S.D.); (C.H.)
| | - Christophe Hano
- Laboratoire de Biologie des Ligneux et des Grandes Cultures (LBLGC), INRAE USC1328, Université d’Orléans, 28000 Chartres, France; (S.D.); (C.H.)
| | - Bilal Haider Abbasi
- Department of Biotechnology, Quaid-i-Azam University, Islamabad 45320, Pakistan;
| | - Sumaira Anjum
- Department of Biotechnology, Kinnaird College for Women, Lahore 54000, Pakistan; (A.K.K.); (H.K.); (S.S.J.)
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Smith DR. Haematococcus lacustris: the makings of a giant-sized chloroplast genome. AOB PLANTS 2018; 10:ply058. [PMID: 30393516 PMCID: PMC6205361 DOI: 10.1093/aobpla/ply058] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2018] [Accepted: 09/27/2018] [Indexed: 05/23/2023]
Abstract
Recent work on the chlamydomonadalean green alga Haematococcus lacustris uncovered the largest plastid genome on record: a whopping 1.35 Mb with >90 % non-coding DNA. A 500-word description of this genome was published in the journal Genome Announcements. But such a short report for such a large genome leaves many unanswered questions. For instance, the H. lacustris plastome was found to encode only 12 tRNAs, less than half that of a typical plastome, it appears to have a non-standard genetic code, and is one of only a few known plastid DNAs (ptDNAs), out of thousands of available sequences, not biased in adenine and thymine. Here, I take a closer look at the H. lacustris plastome, comparing its size, content and architecture to other large organelle DNAs, including those from close relatives in the Chlamydomonadales. I show that the H. lacustris plastid coding repertoire is not as unusual as initially thought, representing a standard set of rRNAs, tRNAs and protein-coding genes, where the canonical stop codon UGA appears to sometimes signify tryptophan. The intergenic spacers are dense with repeats, and it is within these regions where potential answers to the source of such extreme genomic expansion lie. By comparing ptDNA sequences of two closely related strains of H. lacustris, I argue that the mutation rate of the non-coding DNA is high and contributing to plastome inflation. Finally, by exploring publicly available RNA-sequencing data, I find that most of the intergenic ptDNA is transcriptionally active.
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Affiliation(s)
- David Roy Smith
- Department of Biology, University of Western Ontario, London, Ontario, Canada
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Gaouda H, Hamaji T, Yamamoto K, Kawai-Toyooka H, Suzuki M, Noguchi H, Minakuchi Y, Toyoda A, Fujiyama A, Nozaki H, Smith DR. Exploring the Limits and Causes of Plastid Genome Expansion in Volvocine Green Algae. Genome Biol Evol 2018; 10:2248-2254. [PMID: 30102347 PMCID: PMC6128376 DOI: 10.1093/gbe/evy175] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/07/2018] [Indexed: 12/25/2022] Open
Abstract
Plastid genomes are not normally celebrated for being large. But researchers are steadily uncovering algal lineages with big and, in rare cases, enormous plastid DNAs (ptDNAs), such as volvocine green algae. Plastome sequencing of five different volvocine species has revealed some of the largest, most repeat-dense plastomes on record, including that of Volvox carteri (∼525 kb). Volvocine algae have also been used as models for testing leading hypotheses on organelle genome evolution (e.g., the mutational hazard hypothesis), and it has been suggested that ptDNA inflation within this group might be a consequence of low mutation rates and/or the transition from a unicellular to multicellular existence. Here, we further our understanding of plastome size variation in the volvocine line by examining the ptDNA sequences of the colonial species Yamagishiella unicocca and Eudorina sp. NIES-3984 and the multicellular Volvox africanus, which are phylogenetically situated between species with known ptDNA sizes. Although V. africanus is closely related and similar in multicellular organization to V. carteri, its ptDNA was much less inflated than that of V. carteri. Synonymous- and noncoding-site nucleotide substitution rate analyses of these two Volvox ptDNAs suggest that there are drastically different plastid mutation rates operating in the coding versus intergenic regions, supporting the idea that error-prone DNA repair in repeat-rich intergenic spacers is contributing to genome expansion. Our results reinforce the idea that the volvocine line harbors extremes in plastome size but ultimately shed doubt on some of the previously proposed hypotheses for ptDNA inflation within the lineage.
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Affiliation(s)
- Hager Gaouda
- Department of Biology, University of Western Ontario, London, Ontario, Canada
| | - Takashi Hamaji
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Japan
- Department of Biological Sciences, Graduate School of Science, Kyoto University, Japan
| | - Kayoko Yamamoto
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Japan
| | - Hiroko Kawai-Toyooka
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Japan
| | - Masahiro Suzuki
- Kobe University Research Center for Inland Seas, Awaji, Hyogo, Japan
| | - Hideki Noguchi
- Center for Genome Informatics, Joint Support-Center for Data Science Research, Research Organization of Information and Systems, Mishima, Shizuoka, Japan
- Advanced Genomics Center, National Institute of Genetics, Mishima, Shizuoka, Japan
| | - Yohei Minakuchi
- Center for Information Biology, National Institute of Genetics, Mishima, Shizuoka, Japan
| | - Atsushi Toyoda
- Advanced Genomics Center, National Institute of Genetics, Mishima, Shizuoka, Japan
- Center for Information Biology, National Institute of Genetics, Mishima, Shizuoka, Japan
| | - Asao Fujiyama
- Advanced Genomics Center, National Institute of Genetics, Mishima, Shizuoka, Japan
| | - Hisayoshi Nozaki
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Japan
| | - David Roy Smith
- Department of Biology, University of Western Ontario, London, Ontario, Canada
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