Homoeologous chromosome pairing between the A and B genomes of Musa spp. revealed by genomic in situ hybridization

• Published in: Annals of botany Vol. 108; no. 5; pp. 975 - 981
• Main Authors: Jeridi, Mouna, Bakry, Frédéric, Escoute, Jacques, Fondi, Emmanuel, Carreel, Françoise, Ferchichi, Ali, D'Hont, Angélique, Rodier-Goud, Marguerite
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01.10.2011; Oxford University Press (OUP)
• Subjects: Breeding; Chemical and Process Engineering; Chromosome Pairing; Chromosomes; Chromosomes, Plant; DNA, Plant - genetics; Engineering Sciences; Evolutionary genetics; Food engineering; Gene Transfer, Horizontal; Genomes; Genomics; Hybridity; Hybridization, Genetic; In Situ Hybridization; Life Sciences; Medical genetics; Meiosis; Musa; Musa - cytology; Musa - genetics; Musa acuminata; Polyploidy; Technical; TECHNICAL ARTICLE; Triploidy; banana; meiosis; polyploidy; genomic; interspecific hybrid; hybridization; homoeologous chromosomes pairing; Musa, banana, genomic in situ hybridization, meiosis, homoeologous chromosomes pairing, interspecific hybrid, polyploidy
• ISSN: 0305-7364; 1095-8290
• DOI: 10.1093/aob/mcr207

• Background and Aims Most cooking banana and several desert bananas are interspecific triploid hybrids between Musa acuminata (A genome) and Musa balbisiana (B genome). In addition, M. balbisiana has agronomical characteristics such as resistance to biotic and abiotic stresses that could be useful to improve monospecific acuminata cultivars. To develop efficient breeding strategies for improving Musa cultivare, it is therefore important to understand the possibility of chromosome exchange between these two species. • Methods A protocol was developed to prepare chromosome at meiosis metaphase I suitable for genomic in situ hybridization. A series of technical challenges were encountered, the main ones being the hardness of the cell wall and the density of the microsporocyte's cytoplasm, which hampers accessibility of the probes to the chromosomes. Key parameters in solving these problems were addition of macerozyme in the enzyme mix, the duration of digestion and temperature during the spreading phase. • Results and Conclusions This method was applied to analyse chromosome pairing in metaphase from triploid interspecific cultivars, and it was clearly demonstrated that interspecific recombinations between M. acuminata and M. balbisiana chromosomes do occur and may be frequent in triploid hybrids. These results provide new insight into Musa cultivar evolution and have important implications for breeding.