Functional analysis of different promoter haplotypes of the coffee (Coffea canephora) CcDREB1D gene through genetic transformation of Nicotiana tabacum
In many higher plants, DREB genes have been shown to be involved in abiotic stress transduction pathways. Previous results showed that CcDREB1D gene expression increased under drought stress in leaves of the drought-tolerant clone 14 of Coffea canephora Conilon but not in those of the drought-susceptible clone 22. Rationale: By sequencing the CcDREB1D promoter regions of these clones, three haplotypes (hp15, hp16 and hp17) containing several single nucleotide polymorphisms and insertions/deletions were found. These haplotypes were cloned independently into the binary vector pBI101 in order to analyze their ability to control the expression of the uidA reporter gene in transgenic tobacco plants under different stress conditions. Methods: The three haplotypes of CcDREB1D promoter sequences fused to the uidA reporter gene were transferred in N. tabacum cv. SRI via A. tumefaciens mediated transformation. Kanamycin-resistant plants were subjected to dehydration (DH), heat shock (HS) and cold (CS) stresses and further analyzed by histochemical GUS assays and expression of uidA by qPCR experiments. Results: Under DH and HS conditions, GUS activity was detected in petioles and youngest leaves of pD22-hp17L-transformed tobacco after 6h of stress. Under CS conditions, GUS staining was detected after 36h and 48h of stress, mainly in leaf lamina, petioles and vascular tissues, but not in roots of pD14-hp15L-transformed tobacco. In pD22-hp17L-transformed plantlets, GUS activity was detected after 12h, 24h, 36h and 48h of CS treatment, mainly in leaf petioles and midribs. In pD14-hp16L-transformed plantlets, CS treatment also induced uidA gene expression that did not present significant variations over stress duration. For all these constructions, uidA gene expression was not detected in unstressed conditions and recovered tobacco plantlets. Conclusions &Perspectives: Our results clearly suggest that (1) the hp 17 haplotype of the CcDREB1D promoter functioned in a different manner in the DH/HS and CS treatments in transformed-tobacco plants and (2) the three CcDREB1D promoter haplotypes of CcDREB1D gene were inducible by abiotic stress in tobacco by with a weaker strength compared to that of the constitutive CaMV35S promoter. These results clearly support theidea that the molecular mechanisms implicated in the transcriptional control of DREB gene expression by abiotic stress are probably highly conserved between tobacco and coffee plants. (Texte intégral)
| Main Authors: | , , , , , |
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| Format: | conference_item biblioteca |
| Language: | eng |
| Published: |
ASIC
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| Subjects: | F30 - Génétique et amélioration des plantes, F60 - Physiologie et biochimie végétale, H50 - Troubles divers des plantes, |
| Online Access: | http://agritrop.cirad.fr/582721/ http://agritrop.cirad.fr/582721/7/PB231%20Aquino%20et%20al%20ASIC%202016%20v2.pdf |
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