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Sainsbury Laboratory

Research Interests

I am a developmental biologist interested in flower development and morphogenesis and in particular the mechanisms flowers has evolved to promote successful reproduction. Through my research, I am aiming to gain a deeper understanding of the developmental mechanisms behind plant reproduction using multidisciplinary and quantitative approaches (microscopy, genetics, computational and mechanical modelling and bumblebee behavioural assays).

 

Plant reproduction and mechanics

After a Master’s degree in life sciences specialising in agriculture, agronomy and forestry (Ecole d’Ingenieurs de Purpan, Toulouse, France), I was awarded of a doctoral fellowship (French Ministry of Higher Education, Research, and Innovation) to complete a PhD at the Laboratoire de Reproduction et Développement des Plantes at ENS Lyon (Cell Signaling team) under the supervision of Thierry Gaude and Isabelle Fobis-Loisy.

I studied the mechanisms of pollination in Arabidopsis thaliana, focusing on the very first step of male-female interaction, when a pollen grain lands on the female epidermis (surface of stigma). It was unknown how the pollen tube orients itself when it emerges from the pollen at the stigmatic cells (female) surface. I showed how mechanical properties of the stigmatic cell wall guide the pollen tube toward the ovule direction, using diverse microscopy techniques (time-lapse confocal microscopy, scanning electron microscopy and atomic force microscopy) as well as genetic and computational and mechanical modelling. 

In addition, I studied the dynamic adaptations of stigmatic cell behaviour to intruder identity, by comparing the cellular changes induced in the stigmatic cell after penetration of a pollen tube (welcomed) and Phytophthora parasitica infection (unwanted pathogen).

 

At the very first step of male-female interaction in Arabidopsis thaliana (A), when wild-type pollen grain lands on the female epidermis, the pollen tube grows in the direction straight towards the ovules (B). However, when the mechanical properties of the stigmatic cell wall are impaired, wild-type pollen tubes lack direction, coiling around the stigmatic cells (C). Image credit: Lucie Riglet.

 

Flower morphogenesis and patterning

Seeking to broaden my knowledge about flower development, I started my postdoctoral research at the Sainsbury Laboratory, University of Cambridge, in the Moyroud lab, which uses Hibiscus trionum as an emerging model system. As a Herchel Smith Postdoctoral Research Fellow, I am investigating how plants pattern their petals to communicate with pollinators, focusing on how spatial patterns of cell behaviour emerge and persist as the tissue grows into a functional organ. I have recently developed a quantitative imaging pipeline and deciphered the mechanisms specifying the distinct bullseye regions in developing petals of Hibiscus trionum combining imaging, genetics, computational modelling and bumblebee behaviour assays. We have shown that the H. trionum petal epidermis is pre-patterned, with the boundary specified long before the bullseye pattern becomes visible. We have identified some of the mechanisms leading to vary petal pattern proportions. Petal patterns are thought to enhance flower attractiveness, but it was unknown if pollinators prefer specific bullseye sizes. Using behavioural assays, we found that bumblebees use bullseye proportions as a cue to identify targets and that they prefer medium-sized bullseye dimensions.

Hibiscus trionum petals with a boundary at the one-third position separating the purple proximal region and white distal domain (A). At early developmental stages, when the petal is still greenish, lacking of any differentiation sign, a pre-pattern is already specifying the boundary region of the petal at maturity (B). We identified the mechanisms behind pattern variations, using Hibiscus richardsonii, a sister species (C). We tested bumblebees with artificial flowers mimicking H. trionum (medium) and H. richardsonii (small) bullseye sizes, and found that bumblebees preferred the medium-sized bullseye. Image credits: Lucie Riglet.

 

Video communicating the key findings from our recent petal patterning research aimed at a general public audience.

 

Science Communications and Outreach

I like sharing my research and microscopy images and contribute to the Sainsbury Outreach Committee in developing and running science engagement activities for public outreach events, such as the Cambridge Festival, Festival of Plants, Open Cambridge and Big Biology Day. I have also participated in science communication exhibitions, for example, my SEM images were featured in an exhibition for the « Étonnant Vivant » exhibition at the Montparnasse-Bienvenüe station, Paris

 

Plants know how to choose their sexual partners (Lucie Riglet) featured in the Astonishing Living Exhibition at the Montparnasse-Bienvenüe Station.

 

Research Articles

Riglet L., Zardilis A., Fairnie A., Yeo M., Jönsson H., Moyroud E. (2024), Hibiscus bullseyes reveal mechanisms controlling petal pattern proportions that influence plant-pollinator interactions, Science Advances. https://doi.org/10.1126/sciadv.adp5574 

Riglet L., Hok S., Kebdani-Minet N., Le-Berre J., Gourgues M., Rozier F., Bayle V., Bancel-Vallee L., Allasia V., Keller H., da Rocha M., Gaude T., Attard A., Fobis-Loisy I. (2024), Invasion of the stigma by the pollen tube or an oomycete pathogen: striking similarities and differences. Journal of Experimental Botany. https://doi.org/10.1093/jxb/erae308

Riglet L., Quilliet C., Godin C., John K., Fobis-Loisy I. (2024), Geometry and cell wall mechanics guide early pollen tube growth in Arabidopsis thaliana. Under revision. BioRxiv preprint: https://doi.org/10.1101/2024.02.05.578915

Riglet L., Rozier F., Fobis-Loisy L., Gaude T. (2021), KATANIN and cortical organization have a pivotal role in early pollen tube guidance, Plant Signaling and Behavior. https://doi.org/10.1080/15592324.2021.1921992

Kodera C., Just J., Da Rocha M., Larrieu A., Riglet L., Legrand J., Rozier F., Gaude T., Fobis-Loisy I., (2021), The molecular signatures of compatible and incompatible pollination in Arabidopsis, BMC Genomics 22, 268. https://doi.org/10.1186/s12864-021-07503-7

Riglet L., Rozier F., Kodera C., Bovio S., Sechet J., Fobis-Loisy L., Gaude T. (2020), KATANIN-dependent mechanical properties of the stigmatic cell wall mediate the pollen tube path in Arabidopsis, eLife. https://doi.org/10.7554/eLife.57282

Rozier F., Riglet L., Kodera C., Bayle V., Durand E., Schnabel J., Gaude T., Fobis-Loisy L., (2020) Live-cell imaging of early events following pollen perception in self-incompatible Arabidopsis thaliana, Journal of Experimental Botany Volume 71, Issue 9, 9 May 2020, Pages 2513–2526. https://doi.org/10.1093/jxb/eraa008

 

Reviews, Book Chapters or Protocols

Riglet L, and Fobis-Loisy I. (2024), Fast and high-resolution imaging of pollinated stigmatic cells by Tabletop Scanning Electron Microscopy, Under revision, Bioprotocol.

Riglet, L., Fobis-Loisy, I. (2023). Cytoskeleton Remodeling in Arabidopsis Stigmatic Cells Following Pollination. In: Hussey, P.J., Wang, P. (eds) The Plant Cytoskeleton. Methods in Molecular Biology, vol 2604. Humana, New York, NY. https://link.springer.com/protocol/10.1007/978-1-0716-2867-6_16

Riglet L., Gatti S., Moyroud E. (2021), Sculpting the surface: Structural patterning of plant epidermis, iScience. https://doi.org/10.1016/j.isci.2021.103346

Research Associate
Dr Lucie Riglet

Contact Details

Sainsbury Laboratory
University of Cambridge
47 Bateman Street
Cambridge
CB2 1LR