Effects of a domestic exotic species, Magnolia kobus, on the persistence of a rare species, M. stellata

• Project/Area Number: 17H03830
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Forest science
• Research Institution: Nagoya University
• Principal Investigator: Tomaru Nobuhiro 名古屋大学, 生命農学研究科, 教授 (50241774)
• Co-Investigator(Kenkyū-buntansha): 石田 清 弘前大学, 農学生命科学部, 准教授 (10343790) ; 中川 弥智子 名古屋大学, 生命農学研究科, 准教授 (70447837)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Project Status: Completed (Fiscal Year 2019)
• Budget Amount: ¥15,210,000 (Direct Cost: ¥11,700,000、Indirect Cost: ¥3,510,000); Fiscal Year 2019: ¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000); Fiscal Year 2018: ¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000); Fiscal Year 2017: ¥6,890,000 (Direct Cost: ¥5,300,000、Indirect Cost: ¥1,590,000)
• Keywords: 保全遺伝学 / コブシ節 / マイクロサテライト / 外来種 / 雑種形成 / 遺伝子浸透 / 繁殖干渉 / 絶滅リスク / 樹木 / 国内外来種 / 種間交雑 / 植物 / 交雑

Outline of Final Research Achievements

Magnolia kobus (MKO) is not naturally distributed around the habitat of M. stellata (MST). However, because there are planted or escaped MKO trees, interspecific hybridization between MST and MKO may occur. The extinction risk of MST may be increased through this hybridization. In this study, we evaluated the effects of an invasive species, MKO, on the persistence of a rare species, MST. This study revealed that hybrids was formed by interspecific hybridization and furthermore backcrossing between MST and hybrids could give rise to introgression from MKO and MS, and that reproductive interference via pollen flow from MKO or hybrids could decrease the number of purebred seeds for MST. The findings suggest that MKO may adversely affect the persistence of MST.

Academic Significance and Societal Importance of the Research Achievements

樹木の遺伝子汚染を明らかにした研究はあまり見当たらない中で、様々な技術・手法を用いてシデコブシとコブシの交雑がもたらす遺伝子汚染の可能性を指摘した点に学術的意義が見出される。
東海地方の湧水湿地では落葉広葉樹が芽吹く前に、シデコブシの美しい花が一斉に開花し、早春の里山を彩る。シデコブシは湿地保全をアピールする象徴的な種である。コブシとの交雑がシデコブシの絶滅リスクを高めることが明らかになったため、コブシを安易に植栽することやコブシが逸出することの危険性を社会に知らしめることは、シデコブシの保全に繋がるだけでなく、象徴種であることから樹木の外来種問題や関連する問題を社会に周知するよい機会にもなる。

Research Products

• [Journal Article] Population genetic structure and demography of Magnolia kobus: variety borealis is not supported genetically (2019)
  • Author(s): Tamaki, I., Kawashima, N., Setsuko, S., Lee, J. H., Itaya, A., Yukitoshi, K., and Tomaru, N.
  • Journal Title: Journal of Plant Research Volume: 132 Issue: 6 Pages: 741-758
  • DOI: 10.1007/s10265-019-01134-6
  • NAID: 120006797864
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Reduced incompatibility in the production of second generation hybrids between two Magnolia species revealed by Bayesian gene dispersal modeling (2017)
  • Author(s): Tamaki, I., Tani, S., Setsuko, S., Ueno, S., Wadasaki, N., and Tomaru, N.
  • Journal Title: American Journal of Botany Volume: 104 Issue: 10 Pages: 1546-1555
  • DOI: 10.3732/ajb.1700138
  • NAID: 120006374955
  • Peer Reviewed
• [Presentation] Effects of a native invasive species, Magnolia kobus, on the persistence of a rare species, M. stellate. (2019)
  • Author(s): Tomaru, N., Wadasaki, N., Yukitoshi, K., Tamaki, I., Setsuko, S, and Ishida, K.
  • Organizer: XXV IUFRO World Congress
  • Int'l Joint Research
• [Presentation] 景観スケールにおけるシデコブシとコブシの種間雑種の分布拡大 (2019)
  • Author(s): 和田﨑直隆、村松正雄、戸丸信弘
  • Organizer: 第130回日本森林学会大会
• [Presentation] シデコブシとコブシ間の人工授粉実験による繁殖干渉の評価 (2018)
  • Author(s): 和田﨑直隆, 石田清, 戸丸信弘
  • Organizer: 第129回森林学会大会
• [Presentation] シデコブシとタムシバの種間雑種における生態的・遺伝的特徴 (2017)
  • Author(s): 和田﨑直隆, 玉木一郎, 鈴木節子, 戸丸信弘
  • Organizer: 第7回中部森林学会大会