samedi 14 avril 2018

Fusariose de la vanille : un danger planétaire

VaBiome teams from Paris, Reunion and French Polynesia published a paper  "Fusariose de la vanille : un danger planétaire" by M. Dron, T. Atuahiva, S. Lepers, P. Besse, M. Grisoni  in Jardins de France #649 (Avril 2018).

lundi 1 mai 2017

A new publication for the Vabiome team in April 2017

Vabiome (Reunion, Paris and French Polynesia teams) has published in Genome Bio. Evol. "DNA Remodeling by Strict Partial Endoreplication in Orchids, an Original Process in the Plant Kingdom" by Spencer C. Brown, Mickaël Bourge, Nicolas Maunoury, Maurice Wong, Michele Wolfe Bianchi, Sandra Lepers-Andrzejewski, Pascale Besse, Sonja Siljak-Yakovlev, Michel Dron and Béatrice Satiat-Jeunemaître.

DNA remodeling during endoreplication appears to be a strong developmental characteristic in orchids. In this study, we analyzed DNA content and nuclei in 41 species of orchids to further map the genome evolution in this plant family. We demonstrate that the DNA remodeling observed in 36 out of 41 orchids studied corresponds to strict partial endoreplication. Such process is developmentally regulated in each wild species studied. Cytometry data analyses allowed us to propose a model where nuclear states 2C, 4E, 8E, etc. form a series comprising a fixed proportion, the euploid genome 2C, plus 2–32 additional copies of a complementary part of the genome. The fixed proportion ranged from 89% of the genome in Vanilla mexicana down to 19% in V. pompona, the lowest value for all 148 orchids reported. Insterspecific hybridization did not suppress this phenomenon. Interestingly, this process was not observed in mass-produced epiphytes. Nucleolar volumes grow with the number of endocopies present, coherent with high transcription activity in endoreplicated nuclei. Our analyses suggest species-specific chromatin rearrangement. Towards understanding endoreplication, V. planifolia constitutes a tractable system for isolating the genomic sequences that confer an advantage via endoreplication from those that apparently suffice at diploid level.

mercredi 7 décembre 2016

A new publication from VaBiome

Microsatellite Markers Confirm Self‐Pollination and Autogamy in Wild Populations of Vanilla mexicana Mill. (syn. V. inodora) (Orchidaceae) in the Island of Guadeloupe

By Rodolphe Laurent Gigant, Narindra Rakotomanga, Chloe Goulié, Denis Da Silva, Nicolas Barre, Gervais Citadelle, Daniel Silvestre, Michel Grisoni and Pascale Besse 

This article is part of the  "Microsatellite markers" book edited by Ibrokhim Y. Abdurakhmonov, ISBN 978-953-51-2798-7,

and is available for free in open access here

jeudi 13 octobre 2016

New publications from Vabiome

Part of the work on Vanilla humblottii in Mayotte was published as "combining pollination ecology and fine-scale spatial genetic structure analysis to unravel the reproductive strategy of an insular threatened orchid" in SAJB

Different vanilla accessions and species were assessed with regards to their resistance to Fusarium and the work was published in Frontiers in Plant Science

mardi 16 juin 2015

VaBiome final seminar in Raiatea (French Polynesia) - 13-17 July 2015

Exploring vanilla biodiversity from the Caribbean to the Indian ocean to the Pacific

Better know, preserve and enhance the biodiversity of vanilla in European tropical regions, this is the objective of the research project VaBiome, which was launched in March 2012, within the Net-Biome networkThe project is funded by the national agency of research (ANR) and the Reunion Region.

For each territory, involved in the VaBiome project, the objective is to better know, preserve and improve its vanillaFor La Reunion and Tahiti, it is above all to improve its quality; for Guadeloupe, to start or revive production of vanilla, but also preserve wild species, as in Mayotte in the Comoros areaThe aim is, for the researchers involved, to identify and study the biodiversity of vanilla, via surveys in forests or plantations, mainly in Guadeloupe and the Comoros. Then follows a study of genetic diversity, leading to the last step: the improvement of the quality of cultivated vanilla and the protection of wild species.

After a launch workshop at the Pôle de Protection des Plantes in Saint-Pierre, Reunion island, from 6th to 9th of March, 2012, the teams from Tahiti, Guadeloupe, Réunion, Mayotte and Paris gathered from the 22d to 26th of May 2014 in Guadeloupe under the aegis of the National Park for a mid-term meeting.

Vabiome comes to an end on the 31th of August 2015. The participants will gather for a meeting of work and final restitution from the 13th to the 17th of July in Raiatea in French Polynesia organized by EVT.

Many knowledge on the ecology and the evolution of species of the genus Vanilla (including V.humblotii in Comoros, V. mexicana in Guadeloupe, and species of the germplasm collections of the CRB Vatel in Reunion and the EVT in Polynesia) have been acquired (genetics, cytogenetics, floral perfumes, disease resistance) and have resulted in concrete preservation and improvement actions.Thus, the research targeted a species native and endangered in Mayotte and the Comoros, V. humblotii, and allowed to start actions of preservation both in situ and ex situ in Mayotte and the drafting of a National Plan of Action (PNA). The tropical American species V. pompona was used as a parent in a cross with the species cultivated in Polynesia V. × tahitensis to produce offspring in which important agronomic characters are being evaluatedA new variety of the species cultivated in La Reunion, V. planifolia, improved for its resistance to the Fusarium fungus has also been selected.

The VaBiome team in Raiatea