Adam Hélène. 2000. Recherche et caractérisation de marqueurs d'expression associés à l'anomalie mantled chez le palmier à huile (Elaeis guineensis Jacq.). Toulouse : s.n., 42 p. Mémoire d'ingénieur : Biotechnologies appliquées au végétal : Université Paul Sabatier
Résumé : The IRD/CIRAD group has developed a micro-propagation process based on somatic embryogenesis of Elaeis guineensis Jacq. However , the occurrence of somaclonal variants (5%), displaying a phenotype known as mantled, currently hampers the scaling-up of clonal plant production. The abnormality, which is unstable over a period of years is characterized by an altered floral morphology and often in the reduction of flower fertility and oil yield. In order to improve the reliability of the micropropagation process, an approach based on differential gene expression analysis, using differential display performed on normal/variant plant material, was developed to identify molecular markers of the mantled phenotype. Using this approach, 37 potential cDNA clones were isolated from shoot apices. In this study, each of the putative markers was tested separately by northern hybridisation to check its differential profile. These experiments confirmed the differential expression profile of around half of the ddRT markers. Two markers, m6B and m13A, were extensively characterized in a wider range of tissue cultures of different genotypes and at different stages of the regeneration process. Screening of shoot apex cDNA libraries was carried out in order to isolate and characterise full length cDNAs. m6B transcript accumulation was found to be generally greater in abnormal than in normal shoot apices and leaves. The m6B cDNA nucleotide sequence reveals a coding sequence of 320 amino acids (36 kDa) sharing significant homology with the lisp 90. The m13A gene displays accumulation of a 2,4kb transcript in normal shoot apices of different genotypes. A putative full length coding sequence has been isolated. The 688 amino acid polypeptide encoded by the m13A gene displays similarities with cellulose synthase. This work should help to improve our understanding of the induction and the molecular mechanisms giving rise to the mantled abnormality during the regeneration process. The availability of reliable markers should make it possible in the future to develop tests for clonal conformity allowing the elimination of abnormal plants.
Mots-clés Agrovoc : Elaeis guineensis, variation somaclonale, Embryogénèse somatique, micropropagation, trouble de différenciation sexuelle, marqueur génétique, PCR, sonde nucléique
Classification Agris : F30 - Génétique et amélioration des plantes
F02 - Multiplication végétative des plantes
Auteurs et affiliations
- Adam Hélène, CIRAD-CP-PALMIER (FRA)
Autres liens de la publication
Source : Cirad - Agritrop (https://agritrop.cirad.fr/477177/)
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