We demonstrated that a mutated melon ethylene receptor gene Cm-ETR1/H69A confers reduced ethylene sensitivity in a heterologous plant, Nemesia strumosa. Cm-ETR1/H69A was introduced with a missense mutation that converted the His 6 9 residue to Ala in the melon ethylene receptor gene Cm-ETR1, as in the Arabidopsis mutant gene etr1-1. Agrobacterium transformation of N. strumosa was performed, and 26 putative transformants with Cm-ETR1/H69A were obtained. Southern blot analysis confirmed the integration of the Cm-ETR1/H69A gene into the genomes of 23 of the putative transformants, and RT-PCR analysis confirmed Cm-ETR1/H69A mRNA expression in all of the transformants. Six of the 23 transformants were selected randomly, and flower longevity was evaluated. All the transformants had significantly extended flower longevity compared with that of the wild type. Furthermore, treatment with 5μM 1-aminocyclopropane-1-carboxylic acid (ACC) or aminoethoxyvinylglycine (AVG) had little or no effect on hairy root formation in most of the transgenic plants. By contrast, in the wild type, AVG treatment reduced hairy root formation and ACC treatment increased hairy root formation. These results indicate that transformants expressing Cm-ETR1/H69A show reduced ethylene sensitivity.