Isolation and characterisation of a banana CYCD2;1 gene and its over-expression enhances root growth

  • David Talengera
  • Gerrit TS Beemster
  • Wilberforce K Tushemereirwe
  • Karl Kunert
Keywords: CyclinD2, 1 gene, Musa spp., banana transformation, 1 over-expression, root growth.


Stimulation of the cell cycle by over-expression of Arabidopsis CyclinD2;1 enhanced growth in tobacco and rice, but not Arabidopsis. To broaden the range of species and to improve an important crop species for developing countries, a CyclinD2;1 homologue was isolated from an East African highland banana cultivar ‘Nakasabira’ (Musa spp., AAA group) and designated Musac;CYCD2;1 (Genebank accession no HQ839770). Musac;CYCD2;1 amino-acid sequence exhibited 40, 54, 57 and 57% identity with CYCD2;1 sequences of Arabidopsis, rice, maize and wheat, respectively. Over-expression of Musac;CYCD2;1 driven by the CaMV 35S promoter in cultivar ‘Sukali ndizi’ (AAB) resulted in transformed plants with no significant increase in total banana CYCD2;1 transcripts in the shoot, but up to 66-fold increase of total banana CYCD2;1 transcripts in roots. Correspondingly, transformed plants had no change in above-ground growth but produced longer main roots and more lateral roots under in vitro conditions. A deeper root system was observed in one transgenic line relative to non-transformed plants when grown in soil. Results demonstrate that a banana homologue of Arabidopsis CYCD2;1 can also enhance growth in a homologous background and the potential of enhancing banana root growth.

Key words: CyclinD2;1 gene, Musa spp., banana transformation, CyclinD2;1 over-expression, root growth.


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eISSN: 1684-5315