Seed Development

Team members (Link toward photo board)

Permanent staff
Gwyneth INGRAM (PI)DR CNRS+33 4 72 72 89 82
Sophy CHAMOTT CNRS+33 4 72 72 86 14
Nathalie DEPEGE-FARGEIXMdC UCBL+33 4 72 72 89 85
Ghislaine GENDROTAI INRA+33 4 72 72 86 07
Peter ROGOWSKYDR INRA+33 4 72 72 86 07
Thomas WIDIEZCR INRA+33 4 72 72 86 04
Post-docs & Invited researcher
Nicolas DOLLMaster 2, ENS Lyon+33 4 72 72 86 08
Laurine GILLESPh.D student, ENS Lyon (ED BMIC)+33 4 72 72 39 58
Jeanne LOUE-MANIFELMaster 2, Strasbourg University04 72 72 39 59
Steven MOUSSUPh.D student, ENS Lyon (ED BMIC)+33 4 72 72 89 46
Contract staff
Audrey CREFFIE CNRS+33 4 72 72 89 85
Marie-France GERENTESAI INRA+33 4 72 72 86 10
Jérôme LAPLAIGEIE INRA04 72 72 86 07

Our publications

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Research interest

The aim of the Seed Development team is to decipher the molecular mechanisms that govern seed development (embryo, endosperm and seed coat) in the model plant Arabidopsis and the crop plant maize.
Both the embryo and the endosperm undergo a very precise and tightly regulated development from a single cell into a multi-cellular, highly differentiated organism, permanently co-ordinating their growth with that of the other parts of the seed. While the developmental or early phase of seed development is the main interest of the team, the subsequent filling and maturation phases are also of strong interest for us. Independently of the developmental stage, the goals are to identify and characterize the functions of genes important for the seed biology and to generate knowledges for seed breeding that will better fit the demands of a sustainable agriculture.

Current Projects

- Transcriptional regulation of seed development
- Gene network regulated by ZHOUPI in Arabidopsis and maize
- Crosstalks between Seed coat-Endosperm-embryo
- Role of the DEK1 protein in Arabidopsis and maize
- Positional cloning of the gim (gynogenesis) locus in maize
- Maize transformation

Transcriptional regulation of seed development

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Cereal seeds are the main source of human nutrition and animal feed throughout the world as well as an important resource for biosourced chemistry and alternative energy production. Therefore, the understanding of seed formation in cereals, and in particular the intimate knowledge of the genes involved, their precise function and their regulation is essential for plant breeding efforts aiming at improving seed yield and quality, stabilising seed traits in fluctuating environments or enhancing industrial uses.
Seeds are complex biological systems composed of three compartments (seed coat, embryo, endosperm) that undergo profound changes during their development characterised by three major stages, i.e. morphogenesis, filling and dehydration. The existence of distinct genetic and epigenetic programs for the three compartments and the three stages of seed development is indicated by transcriptomics analyses in the dicot model species Arabidopsis and several other species.

We now want to address:
- establish maize gene expression patterns at different developmental stages and in different seed compartments on a genome wide basis
- study the conservation in maize of the ABI3/FUS3/LEC2/LEC1 regulatory network, which is essential for seed development in Arabidopsis
- determine the function of specific transcription factors in seed development

Gene network regulated by ZHOUPI in Arabidopsis and maize

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One of the major differences between Arabidopsis and maize seeds is the persistence of the endosperm. In Arabidopsis the endosperm is transient, breaking down as the embryo develops to provide space, and possibly nutrients. We have identified The ZHOUPI (ZOU) gene as being required for this process in Arabidopsis. We have also shown that ZOU regulates a signaling pathway which is necessary for the formation of the embryo surface during seed development.
The ZOU protein is conserved in flowering plants and even in club mosses, suggesting that it has an ancient role, possibly regulating the development of the female gametophyte.

We now want to address:
- use transcriptomic approaches to identify downstream targets of ZOU in Arabidopsis, allowing us to pinpoint the processes that usually lead to endosperm breakdown.
- understand the role of ZOU in maize, a plant which naturally has a persistent endosperm. This may teach us more about the ancestral role of ZOU
- unravel the regulatory network surrounding ZOU in both species, by characterization both upstream and co-regulators, and direct targets.

Crosstalks between Seed coat-Endosperm-Embryo

Seed coat (bleu) ; Endosperm (red) ; Embryo (green)
Maize seeds are complex biological systems composed of three compartments: the seed coat (represented in blue on the picture here opposite), the embryo (in green), and its nourishing tissue the endosperm (in red). These tissues undergo profound and tightly synchronize changes during seed development. This emphasizes the necessity to establish communication between these 3 different tissues in order to co-ordinate their developmental programs throughout the seed development. Despite the importance of this communication, how it is achieved remains almost completely unknown.

We now want to address:
- What are the molecular signalling frameworks operating between seed coat, embryo and endosperm tissues?
- What are the effectors of these inter-compartmental signalling pathways?

Role of the DEK1 protein in Arabidopsis and maize

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Wild-type cotyledon (left) vs dek1 cotyledon (right)

DEK1 is a highly conserved and essential protein in both Arabidopsis and maize, and is absolutely required for normal cell fate specification in both the developing embryo and endosperm. A preliminary functional dissection of DEK1 has highlighted its extreme importance for growth co-ordination, making it an interesting candidate for a role in inter-tissue and intercompartmental communication during seed development. DEK1 is a complex and big protein that is made of several predicted transmembrane domains and a cytoplasmic tail that includes a calpain protease moiety and a domain of unknown function.

We now want to address the following questions:
- Which are the biochemical functions of the different DEK1 domains? To reach this goal, we are using a wide array of biochemical approaches.
- Why the loss or gain of DEK1 functions results in such extreme and pleiotropic phenotypes? We are currently characterizing in detail the morphological and physiological phenotypes associated with DEK1 activity with the aim of identifying the pathways this protein is involved in.

Positional cloning of the gim (gynogenesis) locus in maize

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Gynogenesis (the development of the non-fertilised egg cell into a haploid plant) combined with a colchicine-induced chromosome doubling is nowadays a routine procedure in maize breeding. In maize, it is triggered by the pollination of a plant of interest by a so-called inducer line, and a major QTL of the inducing capacity has been identified on chromosome 1. The objective of the project is the positional cloning of this QTL and the identification of the underlying gene as well as to understand the molecular mechanism involved.

We now want to address:
- determine the exact size of the confidence interval by marker densification
- identify additional recombinants in the interval

Maize transformation

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- Maize transformation, technical platform
The role of the platform is to produce transgenic plants that are tools for basic research and are grown exclusively in a confined environment. Created in 2008, the first year of the maize transformation platform was devoted to the establishment of the most widely used maize transformation technique (contact of Agrobacterium with immature embryos) in the team.
The platform is now opened for outside collaborations. For further information please Contact Ghislaine Gendrot

- Improvement of maize transformation
Maize transformation is an essential tool in functional genomics. The currently used standard technique is not very efficient (2 to 5% of the immature embryos put into contact with Agrobacterium tumefaciens are transformed), quite slow (9 months from transformation to T1 seed), limited to a single genotype and labor intensive. The objective of the project is to improve the existing technique and to test innovative transformation tools in maize.
We now want to address:
- establish maize transformation for additional genotypes
- test in planta transformation in maize
- use meganucleases for targeted gene insertion in maize
- use TALEN for gene knockout

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