Elucidation of the evolutionary process of fruit morphology related to seed dispersal

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K14779
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 45030:Biodiversity and systematics-related
• Research Institution: Kagoshima University
• Principal Investigator: Emura Naoko 鹿児島大学, 農水産獣医学域農学系, 助教 (10762114)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 種子散布 / 海岸植物 / 環境適応 / 多型

Outline of Final Research Achievements

Coastal shrub Scaevola taccada has the inter-individual fruit dimorphism of a dispersal-related two fruit morphs. Namely, the individuals either produce fruits with a corky mesocarp, or with a pulpy mesocarp, referred to as cork and pulp morphs, respectively. In this study, we aimed to clarify the molecular differences between the two morphs. Comparative transcriptome analysis revealed differences in the expression levels of genes involved in lignin biosynthesis between the two morphs in fruits after 15 days of flowering. In addition, we have determined the whole genome sequence of one type of the first generation of self-built cork in Iriomote Island. Using this sequence as a reference sequence, we are analyzing it using the QTL-seq method, one of the whole genome linkage analysis methods, and comparing the sequences between the two types.

Free Research Field

生態学

Academic Significance and Societal Importance of the Research Achievements

散布形質の果実形態の変異について、個体間変異はクサトベラを除いて、ほとんどの例が果実色多型である。しかし、多く知られている果実色多型は果実食動物の選好性に違いをもたらしうるが、その違いは餌資源や季節で変動するため、分散能力に明瞭な違いが生じない場合が多い。一方で、クサトベラの二型は海流散布の有無という散布能力と環境選好性に明瞭な違いがあるため、選択圧の違いが検出されやすいと期待される。ハビタットシフトにともなう種子散布形質の分子レベルの進化過程を明らかにした研究はほとんどない。本研究はクサトベラを用いてこの過程を明らかにすることで、果実形態の多様性について新たな理解を深める。