1
|
Kage A, Takahashi K, Nozaki H, Higashiyama T, Baba SA, Nishizaka T. Swimming ability and flagellar motility of sperm packets of the volvocine green alga Pleodorina starrii. PLoS One 2024; 19:e0287561. [PMID: 39024288 PMCID: PMC11257277 DOI: 10.1371/journal.pone.0287561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 06/11/2024] [Indexed: 07/20/2024] Open
Abstract
Eukaryotic flagella collectively form metachronal waves that facilitate the ability to cause flow or swim. Among such flagellated and planktonic swimmers, large volvocine genera such as Eudorina, Pleodorina and Volvox form bundles of small male gametes (sperm) called "sperm packets" for sexual reproduction. Although these sperm packets reportedly have flagella and the ability to swim, previous studies on volvocine motility have focused on asexual forms and the swimming characteristics of sperm packets remain unknown. However, it is important to quantify the motility of sperm packets and sperm in order to gain insights into the significance of motility in the sexual reproduction of planktonic algae. In this study, we quantitatively described the behavior of three flagellated forms of a male strain of Pleodorina starrii-asexual colonies, sperm packets, and single dissociated sperm-with emphasis on comparison of the two multicellular forms. Despite being smaller, sperm packets swam approximately 1.4 times faster than the asexual colonies of the same male strain. Body length was approximately 0.5 times smaller in the sperm packets than in asexual colonies. The flagella from sperm packets and asexual colonies showed asymmetric waveforms, whereas those from dissociated single sperm showed symmetric waveforms, suggesting the presence of a switching mechanism between sperm packets and dissociated sperm. Flagella from sperm packets were approximately 0.5 times shorter and had a beat period approximately twice as long as those from asexual colonies. The flagella of sperm packets were densely distributed over the anterior part of the body, whereas the flagella of asexual colonies were sparse and evenly distributed. The distribution of flagella, but not the number of flagella, appear to illustrate a significant difference in the speeds of sperm packets and asexual colonies. Our findings reveal novel aspects of the regulation of eukaryotic flagella and shed light on the role of flagellar motility in sexual reproduction of planktonic algae.
Collapse
Affiliation(s)
- Azusa Kage
- Department of Physics, Gakushuin University, Toshima-ku, Tokyo, Japan
| | - Kohei Takahashi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Hisayoshi Nozaki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Tetsuya Higashiyama
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Shoji A. Baba
- Department of Biology, Ochanomizu University, Bunkyo-ku, Tokyo, Japan
| | | |
Collapse
|
2
|
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.
Collapse
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.
| |
Collapse
|
3
|
Roy SW. Digest: Three sexes from two loci in one genome: A haploid alga expands the diversity of trioecious species. Evolution 2021; 75:3002-3003. [PMID: 34486115 DOI: 10.1111/evo.14345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 08/31/2021] [Indexed: 11/27/2022]
Abstract
Multicellular eukaryotes exhibit a remarkable diversity of sexual systems; however, trioecy, the coexistence of male, female, and cosexual or hermaphrodite individuals in a single species, is remarkably rare. Takahashi et al. (2021) report the first known instance of trioecy in a haploid organism. In contrast to other known cases of trioecy, the authors report evidence for genetic control of all three sexes by two loci. These results complicate models for sexual system turnover and expand the known diversity of trioecy species in several ways.
Collapse
Affiliation(s)
- Scott William Roy
- Department of Biology, San Francisco State University, San Francisco, California, 94117
| |
Collapse
|