Chromosomal and Molecular Characterization of 45s and 5s rDNA in Musa Spp. Using Fish Probe

Tee, Lu Ying (2019) Chromosomal and Molecular Characterization of 45s and 5s rDNA in Musa Spp. Using Fish Probe. Final Year Project (Bachelor), Tunku Abdul Rahman University College.

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Abstract

Bananas (Musa spp.) are essential food and profit-generating crops for Malaysia. Most of the banana cultivars have arisen from hybridisation between two ancestor diploid species, M. accuminata (A genome) and M. balbisiana (B genome). Banana cultivars are facing crisis now as there are particularly vulnerable to diseases such as tropical race 4 (TR4). To solve this problem, it is necessary to understand the genetic variation between the wild type and the cultivars. In this study, primers were designed to amplify 720 bp region of the 45S rDNA and 409 bp region of the 5S rDNA of the banana genome. In addition, the meiotic analysis in Musa plants was carried out by generating FISH probes targeting 45S rDNA, 5S rDNA and 18S-5.8S-25S of the banana genome. The BLAST results show that the wild type banana samples analysed are similar to M. acuminata (AA) with the identity of 96%. Besides, the results also indicate that the cultivars, i.e. Cavendish, Pisang MAS and Pisang Berangan, are consisted of A genome and have arisen from the hybridisation between M. acuminata and M. acuminata due to the presence of 45S rDNA only. Lastly, the Rastali banana was found to consist of both A and B genome due to the presence of both 5S and 45S rDNA genes, suggesting that which arose from the hybridisation it is a species arose from hybridization between M. acuminata and M. balbisiana. In a nutshell, the wild type Musa species and its cultivars undergoing meiosis for cell development, thus further investigation can be carried out to determine chromosome defects during meiosis that may lead to loss of resistance towards diseases during the evolution process.