2018 Fiscal Year Final Research Report

Phylogeny and genetic background of myrmecophytic morphology of Callicarpa saccata (Lamiaceae).

Research Project

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Project/Area Number	15H05236
Research Category	Grant-in-Aid for Scientific Research (B)
Allocation Type	Single-year Grants
Section	海外学術
Research Field	Biodiversity/Systematics
Research Institution	Kumamoto University
Principal Investigator	Soejima Akiko 熊本大学, 大学院先端科学研究部(理), 教授 (00244674)
Co-Investigator(Kenkyū-buntansha)	塚谷裕一東京大学, 大学院理学系研究科(理学部), 教授 (90260512)
Research Collaborator	Okada Hiroshi Nagamasu Hidetoshi Darnaedi Dedy Utami Nandai Suleiman Monica Anak Bibian
Project Period (FY)	2015-04-01 – 2018-03-31
Keywords	系統分類 / 共生進化 / 形態形成
Outline of Final Research Achievements	Callicarpa saccata, an endemic species of Borneo island, is a relative of C. japonica. It is a myrmecophyte plant possessing a pair of sacs inhabited by ants at the leaf base. Our field observation and molecular phylogenetic analyses showed that a few other mymecophytic species provided with extrafloral nectary or branch cavity as mymecophytic features are closely related to C. saccata. It means that coevolution between the plant and ant occurred through a stepwise process in this group. For the genetic background, expression of BOP genes were detected at the leaf base of developing young leaeves of C. saccata, which suggested the relationship between the sac formation and the genetic mutation of these genes.
Free Research Field	植物系統分類学
Academic Significance and Societal Importance of the Research Achievements	生物種は互いにさまざまな相互作用を行いながら，複雑な生態系を形成している．その中でも特に，強い固有の結びつきを持つ特異的な関係は，その進化の過程において影響し合う共進化によって生じてきたと考えられる．アリ植物はその特殊な例のひとつであり，多くの植物のグループで知られている．しかし，本研究で発見されたような，近縁な種間にアリとの段階的な共生系が存在している例は稀であり，共進化の過程を理解する上で大きな意義が認められる．一方，特殊な形態変化が生じる遺伝的背景に関わる遺伝子が特定できたので，今後，形態発生における遺伝子発現のメカミズムとその進化背景についての解明が進むことが期待できる．