Elucidating the impact of respiration on plant and crop carbon balance is a persisting conundrum of physiology since respiration is both detrimental to plant biomass production (carbon loss in the form of CO2) and beneficial for nutrient assimilation (such as nitrogen) and growth. Furthermore, leaf respiration is at the heart of interactions between photosynthesis, photorespiration and mitochondrial metabolism and therefore, it is believed to be orchestrated by a complex regulation network, that may in turn be influenced by environmental changes (e.g. light/dark transition, atmospheric CO2 and temperature). Still, there are presently many enduring uncertainties about respiratory function in photosynthetic organs. So is the case of (i) possible robust relationships between ecophysiological leaf traits and respiration rate, (ii) fundamental fluxes that describe respiratory gas exchange, (iii) metabolic flux patterns associated with respiration and (iv) the effect of respiration on carbon and isotopic balance. In the present project, we intend to use post-genomic approaches (mainly, proteomics, fluxomics and isotopic facilities) to better understand metabolic commitments as well as respiratory responses to environmental conditions, from the cellular to the organ level. We propose to develop mostly in vivo and analytical methods to characterize leaf respiration, identify key regulators and appreciate the impact of respiration on other metabolisms like C1-metabolism. This project takes advantage of our expertise in isotopic methods adapted for plant biology. The ‘generalized fluxomic’ approach proposed in the project (i.e. carrying out extensive flux pattern studies) should provide a neat advance in understanding the metabolic orchestration of plant respiration.

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 five regions involved (Reunion, French Polynesia, Guadeloupe, French Guiana, 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.