Introduction of Ethylene Insensitivity In Flowering Potted Plants by Genetic Modification

One of the effective ways to control ethylene synthesis and ethylene responses in plants is genetic modification. The introduction of the mutant ethylene receptor gene, etr1-1, from Arabidopsis has been proved as the most promising for such purpose, especially when its expression is controlled by a flower specific promoter. Effective regeneration and transformation systems for ethylene sensitive potted plants Kalanchoë and Campanula were established to enable the introduction of etr1-1 mutant gene. Transgenic fertile plants of Campanula carpatica Jacq. and Kalanchoë blossfeldiana Poeln. were obtained by Agrobacterium tumefaciens-mediated transformation using the construct containing etr1-1 gene under the control of the flower specific fbp1-promoter from Petunia. Flowers of T0 lines were tested for their ethylene sensitivity by exposure to 2 µl l^-1 ethylene. Non transgenic flowers of Kalanchoë and Campanula plants wilted within 2-3 days. The best Kalanchoë line had only 1/3 wilted flowers after 10 days of continuous ethylene exposure, while the best transgenic line of Campanula flowered up to 27 days in ethylene.  Use of flower specific promoter successfully prevented introduction of ethylene insensitivity in leaves or roots. The cuttings taken from transgenic Campanula and Kalanchoë plants produced roots. T1 progenies of both plant species, which were established from crosses between transgenic plants and wild plants, showed stable dominant inheritance and expression of etr1-1, which makes the plants useful for breeding program.