PROJECT

Project description

Vanilla is an emblematic patrimonial and endemic resource for tropical EU regions and combines a high socio-economic value with a natural image due to its traditional and sustainable mode of production and process. Tropical EU regions offer a unique opportunity to study the genus in its global biodiversity.

The stake of vanilla sustainability relies on three capacities: Our capacity to protect the wild vanilla species through their conservation and study, our capacity to exploit our knowledge of this biodiversity to diversify the quality of the vanilla product, and our capacity to improve cultivated vanilla (aroma, disease resistance, agronomy).

The four regions involved (Reunion, French Polynesia, Guadeloupe, Mayotte) will share Vanilla genetic resources and biodiversity management and development skills as well as scientific expertise (together with IBP/Paris) to develop these capacities to reach two objectives:The main research objectives of the project are first to improve our scientific knowledge to implement actions in the preservation of vanilla wild genetic resources in tropical UE (both ex situ and in situ) and subsequently, to identify what services wild species can offer for the improvement of cultivated species and the sustainability of vanilla crop production.

We will inventory and characterise (genetic, phenotypic and mechanisms of evolution and diversification) the wide range of Vanilla genetic resources both cultivated and natural in tropical EU to protect and value endemic species and resources. We will also assess important agronomical traits in these species (aroma, resistance to viruses and fusarioses), and how these traits can be combined through hybrid breeding (V. xtahitensis x V. pompona). Innovative candidate gene markers from a collaborative international metagenomic project will be used to implement genome enabled improvement strategies for vanilla. The direct participation of biodiversity management and sustainable development stakeholder partners will allow implementing the results with regards to these two aspects, for each region involved.

VaBiome is a highly structuring project which will contribute to build the future and long term international conservation of the genus diversity as well as the aromatic exploitation of this beloved product.

Objectives

The first objective of this project is to inventory genetic resources of endangered wild Vanilla species present in tropical EU, to survey their genetic diversity at the macro- and microevolutionary scale to implement preservation strategies ex situ and in situ.  The second objective is to assess the potential services wild species can offer for breeding improved Vanilla cultivars and the power of genome-enabled crop improvement strategies

Tropical European regions, and particularly Guadeloupe and Mayotte are rich in endangered wild Vanilla species awaiting for characterisation and protection. A collection of vanilla genetic resources is available in Reunion (BRC Vatel, 400 accessions, 30 species). As Vanilla is considered as a TCG a Taxonomic Complex Group, specific taxonomic identification necessitates appreciating the reproduction modes of the species  (importance of vegetative reproduction/sexual), the possible existence of interspecific hybrids and of polyploids. Associated to morphological descriptors, this data will allow to inventory the species present in these three regions and to set up ex situ collections.

The V. humblotii species from Mayotte is protected, and will more particularly be the focus of a population study of its genetic diversity,  spatial distribution and reproductive biology, in order to implement in situ conservation strategies. A similar approach will be conducted on V. mexicana in Guadeloupe. In order to evaluate the services these wild species can offer for the improvement of cultivated vanilla showing a narrow genetic foundation (V. planifolia and V. x tahitensis), three characters of major agro economical importance will be assessed: resistance to viruses (CymMV) and Fusarium, and the aromatic composition of the fruits. The model species V. pompona (resistant to these diseases and showing peculiar aromatical characteristics) will be used to test for the possibility of genome enabled improvement strategies in V. xtahitensis.

The finalised objective of this project is clearly to allow the characterisation, protection and sustainable use and valorisation of vanilla biodiversity in tropical UE and worldwide.

Work program

Three work packages will be developed, thanks to the sharing of competencies between the different partners (genetics and evolution, phytopathology, aroma chemistry, biodiversity conservation and sustainable development).

The first work package will involve field and forest prospecting in Guadeloupe and Mayotte & Comoros and if necessary, the ex situ preservation of the collected accessions. The management of these ex situ collection (core collection virus indexation) and in situ conservation plan for the species V. humblotii in Mayotte will be implemented. Morphological characterisation (common descriptors) will be performed to gain a preliminary indication of the species taxonomy, and ecological data will be recorder (phenology, habitat, pollinators..)

In the second WP, the combined analysis of molecular phylogenies of the chloroplastic and nuclear DNA associated with cytogenetic analyses (genome sizes, chromosome studies) and morphological taxonomy will allow the identification of the species present, and to optimize their ex situ conservation. The developed molecular technologies  (Reunion) will be transferred to the other partners of the project.

In the third WP, we will use a progeny of a cross  V. xtahitensis x V. pompona created in French Polynesia to follow the transmission of two major traits: CymMV and Fusarium resistance (populations are too young to study fruit aromatic traits). In addition to AFLP and microsatellite markers, we will develop candidate gene markers from the phenylpropanoid pathway thanks to a collaboration via Reunion with an American transcriptomics sequencing prject of the V. planifolia genome. This biosynthetic pathway is implied in the synthesis of numerous aromatic compounds, including vanilla, but is also strongly influenced by biotic stress. These markers will allow to get major insights on the physiological mechanisms involved on the plant –pathogen interactions. The transmission of these characters will be evaluated, and simple early selection markers will be developed for the further characterisation of hybrids that will be produced in future vanilla breeding programs in French Polynesia and other teams (particularly Reunion)