Physical mapping of the 18S-25S and 5S ribosomal RNA genes in diploid bananas

Dolezelova M., Valarik M., Swennen R., Horry Jean-Pierre, Dolezel Jaroslav. 1998. Physical mapping of the 18S-25S and 5S ribosomal RNA genes in diploid bananas. Biologia Plantarum, 41 (4) : 497-505.

Résumé : Fluorescent #in situ# hybridisation (FISH) was used to determine the number and distribution of the 18S-25S and 5S rDNA sites on mitotic chromosomes of 6 wild and 2 edible diploid (2n=22) accessions belonging to the two banana species, #Musa acuminata# and #M. balbisiana#. FISH with the 18S-25S probe resulted in signals on one pair of chromosomes, the position of signals corresponded to the secondary constriction at the end of a short arm. The intensity of labelling was different between the homologues and the larger site corresponded to a larger secondary constriction. This labelling pattern was observed consistently in all genotypes. On the other hand, differences in the number of 5S sites were observed between the accessions. While in some of the wild seeded species, the 5S rDNA was localised on two pairs of chromosomes, hybridisation signals appeared on three pairs of chromosomes in other wild accessions. Quite unexpectedly, only five sites of 5S rDNA were reproducibly observed in the two vegetatively propagated diploid edible cultivars, Pisang Mas and Niyarma Yik, evidence for structural heterozygosity. A dual colour FISH showed that in all accessions, the satellite chromosomes carrying the 18S-25S loci did not carry the 5S loci. The results demonstrate that molecular cytogenetics can be applied to #Musa# an that physical cytogenetic maps can be generated.

Mots-clés Agrovoc : Musa acuminata, Musa balbisiana, adn, localisation de gène, carte génétique, séquence nucléotidique, adn ribosomal

Classification Agris : F30 - Génétique et amélioration des plantes

Auteurs et affiliations

• Dolezelova M., Institute of Experimental Botany (CZE)
• Valarik M., Institute of Experimental Botany (CZE)
• Swennen R., Laboratory of Tropical Crop Improvement (BEL)
• Horry Jean-Pierre, CIRAD-FLHOR-BPA (FRA)
• Dolezel Jaroslav, Institute of Experimental Botany (CZE)

Source : Cirad - Agritrop (https://agritrop.cirad.fr/263679/)

Métriques

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