2025-07-16 北海道大学
北海道大学農学研究院の小出陽平准教授らは、イネの捻れ葉変異体（DSK115）における葉の不規則な捻れのメカニズムを3DマイクロCT解析と数理モデルを用いて解明しました。葉身と葉鞘の左右非対称が成長中に物理的接触を引き起こし、その制約が捻れを誘導することを明らかに。同研究は、細胞レベルの成長差による形質生成に加え、器官同士の物理的相互作用が植物形態形成に果たす重要な役割を示したものです。成果は2025年7月15日付『New Phytologist』にオンライン掲載されました。
イネ捻れ葉変異体で観察された不規則なパターンの葉身の捻れ。本研究では、この捻れが、異なる器官同士の物理的な接触によって生じることを明らかにした（紫：葉身、緑：中肋）。
＜関連情報＞
- https://www.hokudai.ac.jp/news/2025/07/post-1983.html
- https://www.hokudai.ac.jp/news/pdf/250716_pr.pdf
- https://nph.onlinelibrary.wiley.com/doi/10.1111/nph.70322
イネ（Oryza sativa）の葉における左右非対称性は器官の間の物理的相互作用を通じて葉身の捻じれを引き起こす Left–right asymmetry causes twisting in rice (Oryza sativa) leaves via physical interaction between organs
Kiwamu Hikichi, Shuhei Okada, Yoshiki Tokuyama, Seiichiro Miura, Minami Taguchi, Yuji Kishima, Itsuro Takamure, Yohei Koide
New Phytologist Published: 15 July 2025
DOI:https://doi.org/10.1111/nph.70322
Summary
- Shape of plant organs is constrained by other organs within the same plant, yet these constraints remain under-reported. In grasses, new leaves typically develop inside the space formed by the older leaf, which imposes spatial restrictions on the developing leaf. This study focused on the rice (Oryza sativa) mutant, DSK115, which exhibits twisted leaf blades to understand how constraints affect leaf development.
- We quantified 3D shapes of twisted and nontwisted leaves developing inside the cylindrical space formed by the older leaf sheath by micro X-ray computed tomography (micro-CT). We also used computational modelling for qualifying leaf phenotype.
- CT scanning showed physical contact between the inner and outer edges of a leaf blade due to left–right asymmetry in leaf width, and physical inhibition of leaf growth due to reduced space within the enclosing leaf sheath. The simulation models demonstrated these factors could produce a twisted structure like DSK115.
- The study revealed the twisting of leaf blades is consistent with a mechanical explanation by physical contact between the inner and outer edges of a leaf blade and physical inhibition of leaf growth.
