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In the face of increasing water scarcity, adapting breeding programs to target crops for more efficient water use is crucial. This requires a comprehensive knowledge of the plant physiological responses to drought, including the regulation of water status in plant tissues (by stomatal closure) and the determinants of water-use efficiency (the ratio of carbon gain to water use). These challenging questions have been scarcely studied in perennial crops such as apple tree, yet of major economic importance. The proposed project aims at screening the European diversity of apple trees responses to drought to decipher their genetic and physiological determinants. We propose a unique combination of innovative methods developed respectively at the origin (INRA Montpellier) and the host (University Bologna), that will be complementarily used on two core-collections of apple tree (200 varieties each) implanted either at one site or the other. During my stay in Bologna, I measured the dynamic responses (transpiration and growth) to soil water deficit on the Italian collection using high-throughput, air-borne imagery methods developed in Montpellier. I will complement with in planta measurements leaning on physiological methods for which the host has a leading expertise (e.g. fluorimetry), allowing the characterization of many genotypes for water status and carbon assimilation and thus the validation of the results derived from imagery. GWAS and exploration of the underlying genes will allow the identification of the genomic regions involved in the control of these traits and of the causal factors of variation. Results will be confronted to (i) data gathered on young potted plants in order to assess the effect of plant age and production on the responses to drought, and (ii) to data similarly collected in the field in Montpellier on the common genotypes, in order to dissect the effect of interaction between Genotype and Environment (GxE).
My research is mostly focused on the integrated study of plants responses to environmental stimuli. I combine ecophysiology, high-throughput phenotyping and quantitative genetics to explore how plants cope with climate change. Some keywords of special interest to me: water-use efficiency, (night) transpiration, isohydry, ABA, growth, architecture, genetic diversity. I graduated as an agronomist with a specialization in plant breeding at Montpellier SupAgro (2012). I then led my PhD thesis at the “Ecophysiology Lab of Plants under Environmental Stress” (LEPSE) at INRA Montpellier and the University of Adelaide (Australia), where I studied the determinisms of water use in grapevine (2012-15). For a first postdoc, I joined a group working on maize to gain experience in the use of highly performant genomic tools and focus on the determinisms of development and flowering (LEPSE, coll. INRA Le Moulon). I was then awarded a postdoc funding (Agropolis foundation) to join the “Genetic Improvement and Adaptation of Mediterranean and Tropical Plants” unit (AGAP) in Montpellier, where I am currently developing field-based approaches to explore the genetic diversity of apple tree responses to drought. In the same time, I got an AgreenSkills fellowship for a short mobility in Luca Corelli-Grappadelli’s Lab at the University of Bologna.
Coupel-Ledru A, Tyerman S, Masclef D, Lebon E, Christophe A, Edwards EJ, Pantin F, Simonneau T. 2017. Abscisic acid down-regulates hydraulic conductance of grapevine leaves in isohydric genotypes only. Plant Physiology 175(3):11211134.
Coupel-Ledru A, Lebon E, Christophe A, Gallo A, Gago P, Pantin F, Doligez A, Simonneau T. 2016. Reduced night-time transpiration is a relevant breeding target for high wateruse efficiency in grapevine. Proceedings of the National Academy of Sciences 113 (32): 8963-8968.
Millet EJ, Welcker C, Kruijer W, Negro S, Coupel-Ledru A, Nicolas SD, Laborde J, Bauland C, Praud S, Ranc N, Presterl, Tuberosa R, Bedo Z, Draye X, Usadel B, Charcosset A, Van Eeuwijk F, Tardieu F. 2016. Genome-wide analysis of yield in Europe: allelic effects as functions of drought and heat scenarios. Plant Physiology 172: 749-764.
Coupel-Ledru A, Lebon E, Christophe A, Doligez A, CabreraBosquet L, Péchier P, Hamard P, This P, Simonneau T. 2014. Genetic variation in a grapevine progeny (Vitis vinifera L. cvs Grenache×Syrah) reveals inconsistencies between maintenance of daytime leaf water potential and response of transpiration rate under drought. Journal of Experimental Botany 65: 6205-6218.