H. Shinoyama, H. Ichikawa, M. Saitoh-Nakashima, M. Saito, R. Aida, H. Ezura, H. Yamaguchi, A. Mochizuki, K. Nakase, Y. Nishibata, Y. Nomura, H. Kamada
Chrysanthemum (Chrysanthemum morifolium Ramat.) is a well-known ornamental flower with a wide range of colors, shapes and sizes. Recently, concerns have been raised about transgene flow from GM plants to wild relatives. Chrysanthemum is predominantly self-incompatible, but is cross-compatible with wild Compositae plants when pollinated by bees and other insects. We previously reported of the production of insect-resistant GM-chrysanthemum, but in Japan, their cultivation was not permitted in open fields because of the potential risk of collapse of local ecosystems via transgene flow. Therefore, in addition to the insect-resistance, we have introduced a trait conferring infertility upon chrysanthemum to prevent the potential risk of transgene flow by suppressing the expression of DMC1 gene. We isolated a cDNA clone encoding chrysanthemum DMC1 involved in meiotic homologous recombination, provisionally designated CmDMC1, and constructed a binary vector bearing the CmDMC1-RNAi segment and a modified cry1Ab gene for insect resistance in the T-DNA. These genes were located head-to-head under the control of bi-directional promoters from mannopine synthase genes. After treatment of chrysanthemum with Agrobacterium carrying the binary vector, 682 plantlets were regenerated from leaf discs, and 149 lines showed significantly strong resistance to lepidopteran insect larvae. Seven lines exhibited stable male sterility at 10 to 35°C, namely the flowering temperature of chrysanthemum. Moreover, female fertility was very low. F1 plants with the transgenes from GM chrysanthemum showed insect resistance and male sterility, indicating the stable transmission of these traits into the progenies. These genes/traits did not segregate in F1 plants because they are located closely in the same T-DNA region. The new GM chrysanthemums will be very useful for inhibiting transgene flow to wild relatives because of their male sterility. In the future, a safety assessment of them will be carried out in a special netted greenhouse and in closed fields to demonstrate their benefits.
Shinoyama, H., Ichikawa, H., Saitoh-Nakashima, M., Saito, M., Aida, R., Ezura, H., Yamaguchi, H., Mochizuki, A., Nakase, K., Nishibata, Y., Nomura, Y. and Kamada, H. (2012). INTRODUCTION OF MALE STERILITY TO GM CHRYSANTHEMUM PLANTS TO PREVENT TRANSGENE FLOW . Acta Hortic. 937, 337-346
DOI: 10.17660/ActaHortic.2012.937.41
Chrysanthemum morifolium Ramat., transformation, environmental safety assessment

Acta Horticulturae