Discovery of evolutionary conserved genes governing leaflets formation in eudicots plants

The group of Patrick Laufs have identified genes of the regulation network involved in leaflet formation during leaf development. This work has been published in Science (19 december 2008) together with a group from the University of Oxford.

Comparing the simple leaves shape in monocot plants, frequently ribbon shaped as in grasses, to the leaf shape in eudicot plants, a larger diversity of shape does exist in those last one. Their leaves are frequently divided into distinct leaflets variable in number, for example: three in clover and up to seven for chestnut. Leaflets are developed at the margin of very young leaves, at the initiation of its development.

Works on plant development, initiated in the group for more than ten years, has shown that the NAM/CUC regulatory genes’ family is involved in boundary domains setup between leaves, during their initiation at the tip of shoots in the cruciferous model plant Arabidopsis thaliana. Serrations formation on its simple leaves is also controlled by a member of this regulatory gene family. In Arabidopsis, a natural variation can be observed: leaf margins are more or less incised depending on the gene pool of the wild type plant. The scientists hypothesized that some of these regulators could play a role in leaflets formation in plants with compound leaves.

Comparative study of leaf development in four plants harbouring compound leaves: columbine (Ranunculaceae), tomato (Solanaceae), cardamine (Brassicaceae) and pea (Fabaceae) showed that NAM/CUC3 genes control serration and leafletformation.
The evolutive distance between these four plants and the core of data gathered allow constructing a general model of leafletsand serrations formation: transcriptional factors encoded by the NAM/CUC3 genes would slowdown the growth of margins at the leaf margin provoking limb serration. At the opposite they would activate nearby leaflets formation inducting factors able to activate at their turn NAM/CUC3 genes expression, so bringing to light an auto-activating loop necessary for the establishment of the new tissue. This mechanism could also regulate leaf and flower primordia at the tip of the shoot. A similar mecanism does exist in animal during formation of brain or wings of fly.

(*) Thomas Blein et al. (2008) A conserved molecular framework for compound leaf development. Science 322 (5908), 1835 - 1839 (PubMed) (Abstract | Full Text | PDF)

19 décember 2008

Loïc Lepiniec received the price of plant biology from Académie des sciences for hisworks in integrative biology

Project leader Inra at the Seed Biology Laboratory from the IJPB and head of the Plant Biology Departement, Loïc Lepiniec was honored the 25th november 2008 by the Octave Mirbeau et Valentine Allorge price. This price of plant biology from the Académie des sciences awarded every four years comes to reward its works led since 1996 on the genetic determinism and molecular of the seed quality in the model plant Arabidopsis thaliana.

To understand the genetic determinism and molecular mechanisms controlling seed development and physiology is strategic in a sustainable agriculture context where genetic improvement of seed quality is a key element. Study of seed biology must allow on one hand to provide markers to evaluate seed quality and on the other hand to provide tools to improve plants by classical breeding or plant biotechnology. Together his works participate to a better understanding of seed functioning and allow foreseeing to modify it. He also contributed to methodological improvement in genomic which had an important international impact, collaborating with Georges Pelletier from the Genetics and Plant Breeding Laboratory of IJPB and Michel Caboche from the Plant Genomics Research Unit in Evry.
Along all these years, Loïc Lepiniec and his group identified and characterized numerous genes’ functions involved in seed development and metabolism, particularly concerning oil and flavonoïds biosynthesis. These genes are currently studied by the international scientific community in the model plant Arabidopsis thaliana or crops as rapeseed, maize, potato, vine, strawberry, tomato or rice. He coordinated several international projects, for example the European project FLAVO (2004-2008) on fundamental research aspect and also food quality, nutrition and human health. Flavonoïds are phenolic compounds thought to contribute to prevent cardiovascular diseases and some cancers. Loïc Lepiniec develops henceforth new biological approaches more intégratives as study of regulation networks involved in gene expression. Around fifty scientific publications in international journals and four patents are to his credit.

décember 2008

Discovery of a new class of plant hormones involved in shoot branching

The group of Catherine Rameau, together with groups from the CNRS/University of Toulouse and the University of Queensland, have identified a new plant hormone which controls shoot branching (*). Less than ten hormones controlling development have been described so far. This work has been published in Nature (11 september 2008 issue).

(*) Gomez-Roldan et al. (2008). Strigolactone inhibition of shoot branching. Nature 455, 189-194 (PubMed) (First paragraph | Full Text | PDF)

contact : Catherine Rameau

septembre 2008

Georges Pelletier organized the conference « Aspects of genetics and plant breeding » the 25th march 2008 for his medals ceremony of “insignes de la Légion d’honneur”, l’INRA, Versailles

This ceremony initiated by INRA honour an outstanding scientific who produced pioneering contributions of first order to plant breeding field (haploid plant achievement, device of trangenesis techniques, development of research on the model plant Arabidopsis). This conference recounted some of the major progress in the plant genetics field and its application in plant breeding during the last years (programme). History of this scientific field was recalled as an introduction by Georges Pelletier. Guy Riba, Deputy Director General, in charge of scientific programmes, resources and evaluation, opened the ceremony. He emphasized the major role of Georges Pelletier in new knowledge acquiring and economic impact of his scientific work (hybrids of rape and cabbage, haploid* asparagus). The ceremony was closed with the prizegiving by Jean-Claude Mounolou from “Académie d’Agriculture de France” (see the film).

Georges Pelletier is Director of research “exceptionnel” of the Genetics and Plant Breeding Laboratory and Director of the Genoplante executive comity.
The numerous prizes rewarding his works : the Jean Dufrenoy prize of “Académie d’Agriculture de France” (1986), the Doistaut-Blutet prize from Académie des Sciences (1989) and the prize of friendship of the Great Wall of China (Beijing, 2001) and "premier Laurier de la recherche agronomique INRA" (2006).
Georges Pelletier also is member of the "Académie des Sciences" (2004), member of the “Académie d’Agriculture de France " (2004) and "chevalier de l’Ordre National du Mérite" (1992).

*haploid : concerning a plant harbouring only one copy of its chromosomes

(juin 2008)

FREE Registration (On-line registration is mandatory due to limited seats and open until June 12)

Preserving human health by improving plant food has become a major societal issue.

FLAVO is a European Commission-funded research project aiming at the production of the knowledge and tools necessary to develop healthier and consumer-desirable fruits, vegetables and derived foods/beverages containing optimal levels of flavonoids.

Flavonoids are polyphenolic compounds found in fruits and vegetables that may protect against cancer and cardiovascular diseases and extend lifespan. FLAVO is focused on crops and model plants (e.g. grape, apple, and strawberry) and their derived products (wine, fruit juices and jams). These fruits are rich sources of flavonoids and their derived products are largely consumed.

The development of plant food with specific flavonoid contents is expected to have a direct impact on food quality and human health, to offer new market opportunities, to increase thecompetitiveness of the Agri-Food sector and to reduce health care expenses.

PROGRAMME :

This workshop will present the results obtained within FLAVO and the interest of using flavonoids to develop functional foods. More largely, it will also address industrial applications, market opportunities and consumer attitudes towards functional foods and beverages. These topics will be structured into 4 themes:
•1. Health and Nutrition
•2. Food Quality and Nutrition
•3. Flavonoid Biosynthesis
•4. Socio-Economic Aspects

This workshop will bring together leading researchers and representatives of the academy, consumer organisations,professional federations, unions of crop breeders, agro-food industries and mass press.

ORGANISING COMMITTEE :

• Arnaud Bovy (PRI, Wageningen, The Netherlands)
• Véronique Cheynier (INRA, Montpellier, France)
• Paul Kroon (IFR, Norwich, UK)
• Liisa Lähteenmäki (VTT, Espoo, Finland)
• Loïc Lepiniec (INRA-IJPB, Versailles, France)

FLAVO PROJECT INFORMATION :

• http://flavo.vtt.fi and http://www.flavo.info
• FLAVO booklets, 2005 and 2007.

Additional information, will be available at the FLAVO Workshop 2008 website:
• Registration form
• Detailed program• How to reach the INRA-IJPB Versailles

This workshop is funded by the Conseil Régional de l’Ile de France, the INRA, and the EC.

(february 2008)

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