The team aims to decipher mechanisms that govern seed development in the model plant Arabidopsis and the crop plant maize.

Current Projects

– Communication between seed compartments
– Haploid embryo induction
– Mechanics of seed development
– Gene Editing & Maize transformation

Communication between seed compartments

Leaders: Gwyneth INGRAM & Nathalie DEPEGE-FARGEIX (Arabidopsis) / Thomas WIDIEZ (maize)

Seeds are complex biological systems composed of three compartments: the maternal tissues (represented in green on the picture here opposite), the embryo (in red), and its nourishing tissue the endosperm (in blue). In addition to actively importing and exporting nutrients, these tissues also undergo profound and tightly synchronized developmental transitions during seed development. This emphasizes the need to establish communication between these three different tissues in order to co-ordinate their developmental programs throughout the seed development.

The main questions tackled in the two plant models (Arabidopsis and maize) are:
– What are the signaling mechanisms and frameworks operating between the three main seed compartments?
– How is the structure/composition of the apoplast at compartment interfaces controlled, and how does interface structure/composition influence inter-compartmental communication?
( Doll et al. 2020, Current Biology ; Doll et al. 2020, Science ; Doll et al. 2020, Plant Cell ).

Haploid embryo induction

Leader: Thomas WIDIEZ

Peculiar maize lines (called “haploid inducer lines”) present a deviation from the classical plant double fertilization, leading to the production of atypical seeds containing haploid embryos (containing only the maternal genome, and a normal endosperm. Our pioneering work (Gilles et al. 2017, EMBO Journal) identified the underlying mutation in a phospholipase that we named NOT LIKE DAD (NLD) because haploid embryos lack a paternal contribution. This project aims at solving the mystery of how the pollen (male) expressed gene NLD induces maternal (female) haploid embryos. In addition to tackling fundamental questions in plant reproduction (e.g. characterization of the peri-germ cell membrane that wraps the sperm cells (Gilles et al. 2021, JCB ; Sugi et al., 2024, Nature Plants), this project is also strongly connected to plant breeding, because maize haploid inducer lines have become key tools for seed companies as part of in planta doubled haploid technologies, which allow rapid production of perfectly homozygous maize plants (see some of our reviews: Gilles et al. 2017, Current Biology and Jacquier et al. 2020, Nature Plants).

Mechanics of seed development

Leader: Benoit LANDREIN

Using the seed of Arabidopsis as a model system, we are studying how mechanical interactions between tissues and cell responses to mechanical signals control plant organ morphogenesis (Landrein and Ingram, 2019, J Exp Bot). By combining experimental approaches with modelling, performed in collaboration with Olivier Ali from the MOSAÏC team, we recently built a model of seed morphogenesis based on the mechanical interaction between the endosperm and the seed coat. This model allowed us to rethink the contribution of turgor pressure to plant organ growth (Creff, Ali, et al, 2023, Nature Communications). In parallel, we also showed that seed size and shape are the product of two mechanical responses that are triggered each seed coat outer integument layer at distinct developmental stages (Bauer et al, 2024, EmboJ). Building on this work, we are now studying in more depth the molecular mechanisms that determines the mechanical properties and responses of forces of seed coat outer integument cells. To know more, click here to see the dedicated page of the Seed Mechanics Group.

Leader: Thomas WIDIEZ / Platform Animator: Emilie MONTES

Biotechnological research in the team is centered around the maize transformation platform founded in 2008. The vocation of the platform is to produce transgenic maize plants for fundamental research and all plants produced are cultured exclusively in confined environments. The biological questions concern on one hand maize reproduction and kernel development in liaison with the SeedDev team, and on the other flowering time, tolerance to water deficit and nitrogen use efficiency in collaboration with national and international partners. In parallel, technological developments are carried out to improve maize transformation, for example by increasing the transformation rate, by shortening the duration of the transformation process or by adapting it to genome editing by CRISPR/Cas9 (Doll et al. 2019, Plant Cell reports ; Fierlej et al. 2022, Frontiers Plant science).

The platform is opened for outside collaborations. For further information please Contact Emilie MONTES

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