Résumé
Coffea canephora is one of the most economically important coffee species and in Brazil, Conilon being the most widely cultivated plant of this species. Abiotic stresses such as temperature variations and drought periods are factors that significantly affect their production and tend to worsen with globally recognized climate changes. Rationale: In an attempt to understand the molecular responses of coffee plants in water deficit conditions, recent studies have identified candidate genes as CcDREB1D (Dehydration Responsive Element Binding Protein). This gene showed increased expression in response to drought in the leaves of clone 14 (drought tolerant) in relation to the clone 22 (drought susceptible) of C canephora Conilon (Marraccini et al., 2012). Methods: The main objectives of this work were (1) to identify DREB genes and their subgroups (SGs) of C. canephora, and (2) to analyze their expression by reverse transcription-quantitative PCR in leaves and roots of drought-tolerant (14, 73 and 120) and drought-susceptible (22) clones of C canephora Conilon submitted (or not) to drought stress. Results: Among the four subgroups (I-IV) of coffee DREB genes (Alves, 2015), we identified several DREB genes showing differential expression profiles in leaves in response to drought. For several of them, differential expression profiles under drought were observed between drought-tolerant and drought-susceptible clones of C. canephora. This was the case for Cc05_g06840 (SG-I) and Cc08_g13960 (SG-III) DREB that were highly up-regulated by drought in leaves of drought-tolerant clones 14 and 73, but not in those of the drought-susceptible clone 22. Conclusions and Perspectives: The fact that several DREB genes were differentially expressed under drought between drought-tolerant and drought-susceptible clones of C. canephora highly suggests that these genes play a key role in response of coffee plants to this abiotic stress. (Texte intégral)