Antisense suppression of glutamate decarboxylase in tomato (Lycopersicon esculentum L.) results in accumulation of glutamate in transgenic tomato fruits

Abstract

Tomato plants were transformed with a plasmid that contained a the gene for glutamate decarboxylase (GAD) from Lycopersicon esculentum L. coupled, in the antisense orientation, with the constitutively active 35S promoter from cauliflower mosaic virus. Four independent transformants were obtained. In the fruits of these transgenic plants, the level of expression of GAD mRNA was lower than that in non-transgenic plants. When tomatoes were harvested six weeks after the first flowering, we found that the levels of total free amino acids in transgenic fruits were 1.2 to 3.2 times higher than those in non-transgenic plants. In particular, the level of glutamate in fruits of transgenic plants was about twice that in fruits of non-transgenic plants.