Arabidopsis and Musa cyclin D2 expressed in banana (cv. Sukali Ndiizi- AAB) enhances regeneration efficiency

Abstract

Genetic transformation of banana is important because of its polyploidy, sterility and long generation time of most cultivars which limit conventional breeding. However, transformability and regeneration of transgenic lines remains low in bananas. This research reports on the potential of CycD2 genes to improve transformation and regeneration efficiency of banana (cv. “Sukali Ndiizi”). Two genes Arath;CycD2;1 andMusa;CycD2;1 were evaluated for cell cycle modification of the embryogenic cell suspension that is conventionally used in banana genetic engineering at the National Biotechnology Centre, Kawanda. The UidA (GUS) gene was used as reporter gene to establish transient transformation frequency by fusing it with each of the CycD2; 1genes and Cauliflower mosaic virus 35S promoter in the binary vector, pC1305.1. The transformed “Sukali Ndiizi” cells were cultured on selection media and the hygromycin resistant clones developed into shoots. The Gus assay analyses showed a success rate of 80 to 90% for all the constructs including the control, transformed with the empty vector without CycD2; 1 gene. Also, the Gus assay of the regenerants showed that the gene was expressed in different parts of the plants (roots, corm and leaves).Polymerase chain reaction (PCR) analysis of the regenerated shoots gave the regeneration frequency of the embryogenic clones of Arath; CycD2; 1 and Musa; CycD2; 1 gene was 47 and 62%, respectively. This was much higher than that of the control clones without CycD2; 1 (18%). The results show that CycD2; 1 genes have the potential to significantly improve regeneration efficiency of “Sukali Ndiizi” cells”. Key words: Cell cycle genes, reporter gene, genetic transformation, regeneration efficiency.