Résumé
Although some studies in plant physiology resulted in a better understanding of the mechanisms involved in drought tolerance in coffee, knowledge about the metabolic and molecular changes involved in the response of the coffee plant to water deficit conditions is still scarce. Recent studies permitted the identification of several candidate genes presenting differential expression between genotypes contrasting (tolerant vs. susceptible) to this trait. In many higher plants, DREB genes were shown to be involved in the transduction pathways of water stress. Previous results showed that CcDREB1D gene expression increased under drought stress in leaves of drought-tolerant clone 14 but not in those of the drought-susceptible clone 22 of Coffea canephora. By sequencing the DREB1D promoter regions of these clones, several nucleic polymorphisms ("single nucleotide polymorphism" [SNP] and insertion/deletion [INDELs]) were found. In order to know if these polymorphisms could explain the differences of DREB1D gene expression observed between the clones 14 and 22 of C. canephora., 5 'deletions of several alleles of the CcDREB1D promoter regions were made and cloned in the binary vector pBI101 in order to analyze their ability to control the expression of the uidA reporter gene in transgenic tobacco (Nicotiana tabacum) plants. Work supported by CAPES-COFECUB, Consórcio Pesquisa Café and INCT-Café (CNPq/FAPEMIG). (Texte intégral)