Ploidy effects on root growth and chromosome behavior in Arabidopsis thaliana

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K06718
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 44030:Plant molecular biology and physiology-related
• Research Institution: Kanagawa University
• Principal Investigator: Iwamoto Akitoshi 神奈川大学, 理学部, 教授 (60434388)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: ゲノム倍数化 / シロイヌナズナ / 高次倍数化 / 同質倍数化 / 成長解析 / FISH / Whole Mount FISH / 染色体束化

Outline of Final Research Achievements

We performed root growth analysis of the diploid and autopolyploid series of Arabidopsis thaliana using the kinematic method on the cellular basis. The analysis revealed that the autopolyploidization to the tetraploid promoted cell volume growth while it suppressed cell proliferation. In the high polyploids, the autopolyploidization suppressed both cell volume growth and cell proliferation. FISH analysis of cauline leaf cells with centromere-specific probes suggested a possible correlation between the growth properties of the autopolyploid series and the chromosome polytenization.
Then, we directly analyzed the chromosome polytenization in the root tip of Arabidopsis using the whole-mount FISH technique. The results showed that the chromosomes were polytenized and the degree of polytenization was almost the same among the autopolyploids in the cell proliferation zone. In contrast, the chromosomes of high polyploids more polytenized than those of the tetraploid in the volume growth.

Free Research Field

植物形態学

Academic Significance and Societal Importance of the Research Achievements

染色体が通常より増えるゲノム倍数化は、植物では一般的に起きる。本研究により、ある程度までの倍数化は細胞体積の増大をもたらすが、ゲノム倍数化が進み過ぎると細胞増殖と体積増大の両方が抑制されることが示された。また、この成長の抑制は増えた染色体同士が互いにくっつく染色体束化と関連することを明らかにした。この成果は、将来的にゲノム倍数化を利用した生産性の高い新品種の開発などにつながるという意義がある。