A Method to Improve the Embryogenesis Rate of Banana Somatic Cell Embryogenesis

Abstract

Getting embryogenic callus is the first step for banana transformation. Enhancing embryonic-callus-rate is important for banana molecular breeding. In this paper, WIND1, an AP2/ERF transcription factor was added into the embryonic-callus-inducing medium with poly-Arg and nuclear localization signal (NLS). The embryogenic-callus-induced rate of the immature male florescence cultured on the media containing the recombinant protein Arg9-NLS-WIND1 was significantly higher than that of the immature male florescence cultured on the control media. Medium containing 0.01% of the protein Arg9-NLS-WIND1 had the best effect for inducing the embryogenesis of the immature male inflorescence. On the medium containing 0.01% of the protein Arg9-NLS-WIND1, 11.5% of the immature male flowers can develop embryonic callus. On the medium containing Arg9-NLS-WIND1, the protein might be transferred into cytoplasm of the explants by endocytosis due to the interaction between the poly-Arg transduction domain and the plasma membrane. After it entered the nucleus guided by NLS and bind with the target DNA domain, the somatic cell embryogenesis reactions were initiated and the embryonic callus formed.