Duy-Chi Trinh-How do flowers close themselves: the story from Arabidopsis; Liyuan Sui-Cell tilting: A novel mechanism driving three-dimensional epithelial morphogenesis

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• Duy-Chi Trinh-ENS de Lyon, France; University of Science and Technology of Hanoi, Vietnam & Liyuan Sui-Postdoc from Christian Dahmann’s Lab School of Science, Technische Universität Dresden
• Monday 28 October 2024, 14:30-15:30
• Online.

If you have a question about this talk, please contact Jia CHEN.

How do flowers close themselves: the story from Arabidopsis

Dr Duy-Chi Trinh

Affiliations: ENS de Lyon, France; University of Science and Technology of Hanoi, Vietnam

Abstract: Plant reproduction is crucial for plants as well as for humans, as it provides us with flowers, fruits and seeds. The reproductive organs (stamens and pistils) are generally fragile and need to be well protected during their development. The flower bud can close to protect themselves in several ways, for example, by twisting or simply inward curving of sepals or petals. How the floral bud becomes sealed is largely unknown. In this study, we attempt to understand the mechanics of flower closure using the plant Arabidopsis thaliana as the model. In Arabidopsis, the flower is closed thanks to the inward curving of the four sepals. In the outermost sepal, we identified a small region at the sepal tip that is markedly curved inward early on and remains curved even after anthesis. Through modelling and quantitative growth analysis, we find that this hook emerges from growth arrest at the tip at a stage when cortical microtubules align with growth-derived tensile stress. Depolymerizing microtubules specifically at young sepal tips hindered hook formation and resulted in open floral buds. Mutants with defective growth patterns at the tip failed to curve inwards, whereas mutants with enhanced alignment of cortical microtubules at the tip exhibited a stronger hook. We propose that floral buds are locked due to a stress-derived growth arrest event curving the sepal tip and forming a rigid hook early on during flower development.

Cell tilting: A novel mechanism driving three-dimensional epithelial morphogenesis

Dr. Liyuan Sui Abstract Dynamic changes in three-dimensional cell shape and arrangement are crucial for tissue form and function. However, most studies on cell behavior have primarily focused on the apical surface of tissues. Investigating tissue morphogenesis in three dimensions within living tissue presents significant challenges. In our latest research, we explore the developing Drosophila eye, where the progression of an epithelial fold, known as the morphogenetic furrow, drives photoreceptor differentiation. This process involves a series of three-dimensional changes in cell shape and arrangement as the morphogenetic furrow advances from the posterior to the anterior of the eye-antennal disc.

In this study, we employed live imaging of ex vivo cultured eye-antennal discs and quantitative image analysis to demonstrate how the morphogenetic furrow progresses through a series of complex three-dimensional changes in cell shape and arrangement. Ultimately, we identified a cellular tilting mechanism that drives columnar cells to reposition within the epithelium to promote morphogenetic furrow progression and cell differentiation. Given the conservation of morphogenetic processes, we anticipate that similar cell-tilting mechanisms occur in other tissues and organisms.

Join the Zoom with the link: https://cam-ac-uk.zoom.us/j/87503254733 Meeting ID: 875 0325 4733

This talk is part of the Morphogenesis Seminar Series series.

This talk is included in these lists:

• Graduate-Seminars
• Morphogenesis Seminar Series
• Online

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