Comparing the sexualization mechanisms of related species planarians using sex-inducing factors to clarify the evolution of reproductive strategy

• Project/Area Number: 18K06323
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 44040:Morphology and anatomical structure-related
• Research Institution: Tsuyama National College of Technology
• Principal Investigator: Maezawa Takanobu 津山工業高等専門学校, 総合理工学科, 准教授 (90548398)
• Co-Investigator(Kenkyū-buntansha): 柴田 典人 津山工業高等専門学校, 総合理工学科, 教授 (60402781)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Project Status: Completed (Fiscal Year 2021)
• Budget Amount: ¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000); Fiscal Year 2021: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000); Fiscal Year 2020: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000); Fiscal Year 2019: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000); Fiscal Year 2018: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
• Keywords: プラナリア / 有性化 / 生殖器官 / 有性化因子 / 低温 / 有性化機構 / 種間比較

Outline of Final Research Achievements

Planarians have different asexual states depending on the species, and Dugesia ryukyuensis has only ovarian primordia, whereas Dugesia japonica has both ovarian primordia and testicular primordia. The purpose of this study was to clarify the commonalities and differences between various planarian sexualization mechanisms. First, it was clarified that the D. ryukyuensis OH strain was sexualized by administration of sex-inducing factors at 20 ° C, while the SSP strain of D. japonica was sexualized by administration of sex-inducing factors at 14 ° C. In the OH strain, the testis primordia appears at the stage of st.3 when the ovary develops, and develops toward st.5. On the other hand, in the SSP strain, it was clarified that the development of the testis primordia occurs from the early stage of sexualization as in the ovary.

Academic Significance and Societal Importance of the Research Achievements

プラナリア種間の有性化機構の違いを細胞レベルで明らかにした。さらに、これまで有性化しないと考えられていたモデル動物のS.mediterraneaを生殖転換できたことでプラナリア有性化機構を遺伝子レベルで解析する準備が整った。多くの動物が有性化することが知られており、本研究は、それらの機構を理解するための基盤となると考えられる。

Research Products

• [Journal Article] Sex-Inducing Activities of the Land Planarian Bipalium nobile Extract Fractions, Obtained Using Bioassay-Guided Fractionation, in the Freshwater Planarian Dugesia ryukyuensis (2021)
  • Author(s): Makoto Kitamura, Hiroyuki Tanaka, Yurie Horiguchi, Sayaka Manta, Ikuma Saito, Hisashi Iwaya, Hikaru Okamoto, Nanna Nagao, Yumi Yanagihara, Yu Taguchi, Rei Tezuka, Takanobu Maezawa, Kiyono Sekii, Kazuya Kobayashi
  • Journal Title: Zoological science Volume: 38 Issue: 6 Pages: 544-557
  • DOI: 10.2108/zs210029
  • NAID: 210000167061
  • Peer Reviewed
• [Journal Article] D-Tryptophan enhances the reproductive organ-specific expression of the amino acid transporter homolog Dr-SLC38A9 involved in the sexual induction of planarian Dugesia ryukyuensis (2021)
  • Author(s): Takanobu Maezawa, Masaki Ishikawa, Kiyono Sekii, Go Nagamatsu, Ryohei Furukawa, Kazuya Kobayashi
  • Journal Title: Zoological Letters Volume: 7 Issue: 1 Pages: 4-4
  • DOI: 10.1186/s40851-021-00173-z
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Transcriptomic analysis reveals differences in the regulation of amino acid metabolism in asexual and sexual planarians (2019)
  • Author(s): Sekii Kiyono, Yorimoto Shunta, Okamoto Hikaru, Nagao Nanna, Maezawa Takanobu, Matsui Yasuhisa, Yamaguchi Katsushi, Furukawa Ryohei, Shigenobu Shuji, Kobayashi Kazuya
  • Journal Title: Scientific Reports Volume: 9 Issue: 1 Pages: 6132-6132
  • DOI: 10.1038/s41598-019-42025-z
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] A comprehensive comparison of sex-inducing activity in asexual worms of the planarian Dugesia ryukyuensis: the crucial sex-inducing substance appears to be present in yolk glands in Tricladida (2018)
  • Author(s): Nakagawa Haruka、Sekii Kiyono、Maezawa Takanobu、Kitamura Makoto、Miyashita Soichiro、Abukawa Marina、Matsumoto Midori、Kobayashi Kazuya
  • Journal Title: Zoological Letters Volume: 4 Issue: 1 Pages: 14-14
  • DOI: 10.1186/s40851-018-0096-9
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Presentation] プラナリア有性化におけるアミノ酸の役割 (2019)
  • Author(s): 清水辰海, 江川碧唯, 石川正樹, 関井清乃, 古川亮平, 小林一也, 石田哲夫, 前澤孝信
  • Organizer: 日本動物学会第87回
• [Presentation] Mechanisms in ovarian development during sexual induction of the planarian Dugesia ryukyuensis (2018)
  • Author(s): Maezawa T, Shimizu T, Egawa A, Ishikawa M, Sekii K and Kobayashi K
  • Organizer: International Planarian Meeting
  • Int'l Joint Research
• [Presentation] プラナリア有性化過程における卵巣形成機構 (2018)
  • Author(s): 前澤孝信, 清水辰海, 江川碧唯, 石川正樹, 関井清乃, 小林一也
  • Organizer: 日本動物学会第86回