The RG “reproduction and seeds” thematic pole is interested in the sexual part of the plant life cycle; gametophyte development, seed formation and quality. Our groups combine approaches of forward and reverse genetics, functional genomics, biochemistry and structural biology. They aim to identify the genes implicated in these different processes, to elucidate the structure and biological function of proteins and metabolites produced, and to explore network interactions. These questions are addressed essentially in Brassicacea species, either model (Arabidopsis thaliana) or cultivated (Oilseed rape, Brassica napus). We are looking to improved our basic knowledge of sexual reproduction, seed composition and germination capacity in order to provide solutions for the improvement of seed quality for agriculture, the food industry and “green chemistry” (notably the production of hydrid seeds, assuring germination vigour, oil, protein and secondary metabolite contents, improving reserve extraction…).

Groups

The « Organelles and reproduction » team investigates the functional and evolutionary relationships between the plant cell nucleus and two types of organelles, the mitochondria and the chloroplasts. More specifically, the group studies the control of organelle gene expression by nuclear encoded factors, notably the PPR (Pentatrico Peptide Repeat) motif containing proteins. The group is also interested in the evolutionary co-adaptation between these genetic compartments and the effects of these interactions on plant reproduction, in particular in nucleo-cytoplasmic male sterility.

The « Male gametophyte development » team investigates the role of targeted protein degradation through the Ubiquitin Proteasome System (UPS) during microspore and/or pollen development. Previous work of the group and male gametophyte transcriptomic studies suggested that this major regulatory pathway of plant development also plays a key role at the sporophyte-gametophyte transition, and later during the gametophytic (haploid) phase. We want to precise this role through a reverse genetics approach ; in particular, we concentrate our efforts on the characterization of F-box protein gene mutants. F-box proteins are key sub-units of E3 ligase enzymes, responsible for target protein recognition and tranfer towards the proteasome.

The « Seed development and quality » team investigates the genetic, cellular and molecular mechanisms that control the biosynthesis and accumulation of seed storage compounds (lipids and proteins) or secondary metabolites. These compounds are important for animal and human nutrition or health, and for green chemistry. The analyses are performed in different tissues (embryo, endosperm or seed coat) of developing and mature seeds. Our studies currently focus on regulatory networks (mainly at the transcriptional level), transport and storage of the metabolites (e.g. oil bodies).

The « Homeostasis lipid-protein in seed » team aims to identify the main factors (genetic, physiological and environmental) that determine the partitioning between different types of reserves (mainly oil and protein) in Arabidopsis. This model plant is also representative of the European oleaginous plants (rapessed, sunflower) which will allow the transposition of Arabidopsis acquired knowledge’s on crop plants. Moreover, in order to substitute petroleum-derived products by molecules produced by “green chemistry” (i.e synthons), quality production and yield of industrially important crops need to be improved.

The « Dynamic and structure of lipid bodies » team aims to increase the knowledge on the proteins (identity, structure, organisation, interactions, and role) of lipid storage organelles (lipid bodies) in plants and in yeasts. In accordance with the principles of “Green Chemistry”, our research aims to modulate amounts and tailor the
nature of lipids produced, as well as to facilitate storage lipid extraction. Our expertise in the field of half-membrane protein solubilization, and structure determination using spectroscopic (synchrotron radiation circular dichroism, dynamic light scattering) and crystallographic techniques is available to the scientific community.

The « Germination physiology » team studies the control of seed germination quality by diverse factors, in particular abscisic acid (ABA), nitric oxide (NO°), the protein L-isoapartyl methyltransferase (PIMT), flavonoids and the release of polysaccharidic mucilage. Our research aims to analyse the basic mechanisms regulating dormancy, longevity and the response of the seed to the environment.

Publications significatives :

Agrawal GK, Bourguignon J, Rolland N, Ephritikhine G, Ferro M, Jaquinod M, Alexiou KG, Chardot T, Chakraborty N, Jolivet P, Doonan JH, Rakwal R (2010) Plant organelle proteomics: Collaborating for optimal cell function. Mass Spectrom Rev. DOI: 10.1002/mas.2030

Baud S, Bourrellier ABF, Azzopardi M, Berger A, Dechorgnat J, Daniel-Vedele F, Lepiniec L, Miquel M, Rochat C, Hodges M, Ferrario-Mery S (2010) PII is induced by WRINKLED1 and fine-tunes fatty acid composition in seeds of Arabidopsis thaliana. Plant J 64, 291-303

Dubos C, Stracke R, Grotewold E, Weisshaar B, Martin C, Lepiniec L (2010) MYB transcription factors in Arabidopsis. Trends Plant Sci 15, 573-81

Guyon-Debast A, Lécureuil A, Bonhomme S, Guerche P, Gallois JL (2010) A SNP associated with alternative splicing of RPT5b causes unequal redundancy between RPT5a and RPT5b among Arabidopsis thaliana natural variation. BMC Plant Biology 10, 158

Harscoët E, Dubreucq B, Palauqui JC, Lepiniec L (2010) NOF1 encodes an Arabidopsis protein involved in the control of rRNA expression. PLoS One 5(9):e12829

Moison M, Roux F, Quadrado M, Duval R, Ekovich M, Le DH, Verzaux M, Budar F (2010) Cytoplasmic phylogeny and evidence of cyto-nuclear co-adaptation in Arabidopsis thaliana. Plant J 63, 728-738

North H, Baud S, Debeaujon I, Dubos C, Dubreucq B, Grappin P, Jullien M, Lepiniec L, Marion-Poll A, Miquel M, Rajjou L, Routaboul JM, Caboche M (2010) Arabidopsis seed secrets unravelled after a decade of genetic and omics-driven research. Plant J 61, 971-81

Baud S, Wuillème S, To A, Rochat, C, Lepiniec L (2009) Role of WRINKLED1 in the transcriptional regulation of glycolytic and fatty acid biosynthetic genes in Arabidopsis. Plant J 60, 933-947

Berthomé R, Thomasset M, Maene M, Bourgeois N, Froger N, Budar F (2008) pur4 mutations are lethal to the male, but not the female gametophyte and affect sporophyte development in Arabidopsis. Plant Physiol, 147 : 650-60

Dubos C, Le Gourrierec J, Baudry A, Huep G, Lanet E, Debeaujon I, Routaboul JM, Alboresi A, Weisshaar B, Lepiniec L (2008) MYBL2 is a new regulator of flavonoid biosynthesis in Arabidopsis thaliana. Plant J, 55 : 940-53

Guermonprez H, Smertenko A, Crosnier MT, Durandet M, Vrielynck N, Guerche P, Hussey PJ, Satiat-Jeunemaitre B, Bonhomme S (2008) The POK/AtVPS52 protein localizes to several distinct post-Golgi compartments in sporophytic and gametophytic cells. J Exp Bot, 59 : 3087-309

Kopeckný D, Sebela M, Briozzo P, Spíchal L, Houba-Hérin N, Masek V, Joly N, Madzak C, Laloue M (2008) Mechanism-based inhibitors of cytokinin oxidase/dehydrogenase attack FAD cofactor. J Mol Biol, 380 : 886-99

Ogé L, Bourdais G, Bove J, Collet B, Godin B, Granier F, Boutin JP, Job D, Jullien M, Grappin P (2008) Arabidopsis protein repair L-isoaspartyl methyltransferase1 is involved both in seed survival during storage and in germination vigor. Plant Cell, 20 : 3022-3037

Rajjou L, Lovigny Y, Groot SP, Belghazi M, Job C, Job D (2008) Proteome-wide characterization of seed aging in Arabidopsis: A comparison between artificial and natural aging protocols. Plant Physiol, 148, 620-41

Santos-Mendoza M, Dubreucq B, Baud S, Parcy F, Caboche M, Lepiniec L (2008) Deciphering gene regulatory networks that control seed development and maturation in Arabidopsis. Plant J, 54 : 608-20

Uyttewaal M, Arnal N, Quadrado M, Martin-Canadell A, Vrielynck N, Hiard S, Gherbi H, Bendahmane A, Budar F, Mireau H (2008) Characterization of Raphanus sativus pentatricopeptide repeat proteins encoded by the fertility restorer locus for Ogura cytoplasmic male sterility. Plant Cell, 20 : 3331-45

Baud S, Mendoza MS, To A, Harscoët E, Lepiniec L, Dubreucq B (2007) WRINKLED1 specifies the regulatory action of LEAFY COTYLEDON2 towards fatty acid metabolism during seed maturation in Arabidopsis. Plant J, 50 : 825-38

Macquet A, Ralet MC, Loudet O, Kronenberger J, Mouille G, Marion-Poll A, North HM (2007) A naturally occurring mutation in an Arabidopsis accession affects a ß-D-galactosidase that increases the hydrophilic potential of rhamnogalacturonan I in seed mucilage. Plant Cell, 19 : 3990-4006

North HM, De Almeida A, Boutin JP, Frey A, To A, Botran L, Sotta B, Marion-Poll A (2007) The Arabidopsis ABA-deficient mutant aba4 demonstrates that the major route for stress-induced ABA accumulation is via neoxanthin isomers. Plant J, 50 : 810-24