植物の発生進化研究で著名なイギリス・オックスフォード大学のLaura Moody博士とフランス・CNRSのYoan Coudert博士にご講演いただきます。 お二人は、植物が約5億年前に水中から陸上環境に進出し適応する過程でどのようにして複雑な形態が進化してきたのかをコケ植物を使った研究で明らかにされています。Laura Moody博士は立体的な成長メカニズムの進化について、Yoan Coudert博士は葉序の形成機構についてお話しいただく予定です。みなさま奮ってご参加ください。
日時：2024年11月25日（月）15:00〜17:00
場所：片平キャンパス生命科学研究科プロジェクト総合棟1階 講義室A
＊本セミナーは単位認定セミナー兼イノベーションセミナー（2ポイント） * です。
学生のみなさんの積極的な参加を歓迎します。
*イノベーションセミナーの認定は留学生に限る
講演者1
Laura Moody (University of Oxford, UK)
タイトル： Genetic regulation of the 2-dimensional to 3-dimensional growth transition in the moss Physcomitrium patens
要旨：
The evolution of 3-dimensional (3D) growth coincided with the colonization of land by plants approximately 470 million years ago. The acquisition of apical cells that could cleave in three planes, rather than just one or two, allowed plants to develop the characteristics required to successfully survive and reproduce on land. 3D growth is an invariable and fundamental feature of all land plants, and the diverse morphologies exhibited across the globe are a result of the differential regulation of 3D growth processes. Yet, we know relatively little about how 3D growth is regulated at the genetic level. My group has established Physcomitrium patens as a model system to elucidate the genetic pathways underpinning 3D growth. Although the genetic basis remains somewhat elusive, the 3D developmental trajectory is well characterized in P. patens. A series of highly coordinated asymmetric cell divisions convert an initial cell into a leafy shoot (gametophore) bearing a prominent tetrahedral-shaped apical cell capable of 3D growth; self-renewal and the generation of leaf-like phyllids that wrap around the gametophore in a spiral pattern. Using forward genetics, we have isolated ‘no gametophores’ (nog) mutants that fail to establish and/or maintain 3D growth. Invariably, these mutants cannot orient division planes within emerging buds, and bud development arrests early in development. We continue to identify, and functionally characterize, novel regulators of the 2D to 3D growth transition. Our research aims to answer an overarching and fundamental research question –‘How is 3D growth regulated and how did it evolve?’
講演者2
Yoan Coudert (CNRS, France)
タイトル： How a single cell shapes a shoot
要旨： Phyllotaxis, the regular arrangement of leaves around stems, is one of the most striking natural patterns and a primary determinant of plant architecture. Similar phyllotactic patterns have been described in bryophytes and vascular plants, the two major land plant lineages. However, phylogenetic evidence and the fossil record suggest that leaves and leaf-like organs evolved multiple times independently during bryophyte and vascular plant diversification, implying that phyllotaxis arose by convergence in both lineages.
Deciphering how the periodic emergence of leaves is coordinated in space and time at the apex of growing shoots is an enigma that has puzzled biologists, mathematicians and physicists for centuries. Most studies investigating the cellular and molecular basis of phyllotaxis have focused on ferns and angiosperms, leaving the mechanisms underpinning phyllotaxis in bryophytes largely unknown. In bryophytes, phyllotaxis arises from single-celled meristems, raising questions about how asymmetric divisions of a single apical cell create phyllotactic patterns and whether asso-ciated genetic processes are shared across lineages.
To address this fundamental problem, we use the moss Physcomitrium patens as a model system. I will present the quantitative imaging tools that we have developed to characterize phyllotaxis at multiple scales, both in wild-type and mutant genetic backgrounds, and discuss how these approaches have allowed us to pinpoint the contribution of a biochemical-mechanical interplay in the regulation of phyllotactic patterning.
主催：特別推進研究「植物の成長と共生を制御するストリゴラクトンの二面的機能：その起源と進化」
Organizer：植物発生分野 経塚淳子
お問い合わせ：植物発生分野 秦有輝（yuki.hata.a8(at)tohoku.ac.jp）