<p>The 1345-4 line of tomato (Lycopersicon esculentum) was developed through a specific genetic modification of cultivar 91103-114 to exhibit a decreased activity of the enzyme 1- minocyclopropane-1- carboxylic acid (ACC) synthase. This endogenous enzyme is responsible for the conversion of s-adenosylmethionine to ACC, which is the immediate precursor of ethylene, a phytohormone known to play a key role in fruit ripening. The in situ accumulation of ethylene in the transgenic tomatoes is only about 1/50 the level found in the unmodified parental line and the fruit does not fully ripen unless an external source of ethylene is applied. The inbred line 1345-4 tomato was created by Agrobacterium-mediated transformation in which the transfer-DNA (T-DNA) contained a 3&rsquo;-truncated open reading frame corresponding to the sequence of the ACC synthase encoding gene from &ldquo;Golden Nugget&rdquo; tomato. The expression of this truncated ACC synthase gene was controlled by inclusion of sequences from the 35S promoter of cauliflower mosaic virus and the 3&rsquo;-polyadenylation signal from the nopaline synthase (nos) gene from Agrobacterium tumefaciens. In addition, the T-DNA contained sequences encoding the enzyme neomycin phosphotransferase II (NPTII) from the Tn5 transposon of Escherichia coli, strain K12, under the control of the nos promoter from A. tumefaciens. The expression of NPTII activity was used as a selectable trait to screen transformed plants for the presence of the truncated ACC synthase gene. There was no incorporation of translatable plasmid DNA sequences outside of the T-DNA region. While not completely understood, the mechanism of &ldquo;downregulation&rdquo; of the endogenous ACC synthase gene is likely linked to the coordinate suppression of transcription of both the endogenous gene and the introduced truncated ACC synthase gene. While transcription of the truncated ACC synthase gene was detected in transgenic tomato tissues, no expression of a protein product was detectable. The presence of NPTII protein has been judged to be insignificant with respect to any human health risk due to exposure. Alpha-tomatine is the principal naturally occurring glycoalkaloid in tomato, and the level of a-tomatine decreases as the fruit matures so that the amounts in vine-ripened red tomatoes are negligible. The concentration of a-tomatine in immature tomatoes from transgenic line 1345-4 was 1.13-1.37 mg/100g fresh weight tissue, as compared with 3.37-3.59 mg/100g fresh weight tissue for the unmodified 91103- 114 parental line. For ripe red tomatoes, the amounts of a-tomatine from each of these lines were 0.11 and 0.07 mg/100g fresh weight tissue, respectively. Other than reduced ACC synthase activity, the disease, pest and other agronomic characteristics of the transgenic 1435-4 line was comparable to the unmodified parental line.</p><br>