Generation and ethylene production of transgenic carnations harboring ACC synthase cDNA in sense or antisense orientation

Abstract

Carnation (<i>Dianthus caryophyllus</i> L. cv. Nora) plants, transformed with carnation ACC synthase (<i>DC-ACS1</i>) cDNA in sense or antisense orientation (the transgenes are <i>sACS</i> transgene and <i>aACS</i> transgene, respectively) by <i>Agrobacterium-mediated</i> gene transfer were produced. Cut flowers of all the transgenic lines obtained, 2 lines transformed with sACS transgene and 3 lines with <i>aACS</i> transgene, showed suppressed ethylene production during natural senescence as compared with flowers of the non-transformed control line. Among 5 transgenic lines, the sACS-1 line harboring <i>sACS</i> transgene had the severest reduction in ethylene production from flowers, and the flowers lost their vase-life with drying and discoloration in the rim of petals, the ethylene-independent deterioration of carnation flowers. DNA gel blot analysis revealed that the loci of <i>sACS</i> transgenes in the sACS-1 line were different from those in the 6-0-66 line, which is another transgenic line of different origin harboring <i>sACS</i> transgene, although both lines have two copies of the transgenes.