Fructokinase genes and their use in metabolic engineering of fruit sweetness

摘要

This invention provides for novel cDNA and regulatory DNA sequences which modify carbohydrate metabolism in ripening fruit. In order to suppress fructokinase gene expression in transgenic plants and their fruit, we have isolated the cDNA of two tomato fructokinase genes that are expressed in developing and ripening fruit. These cDNA sequences, antisense sequences or ribozymes can be used to suppress expression of the transgenic plant's endogenous genes in ripening fruit by the use of chimeric constructions of the cDNA or antisense using either constitutive or fruit-specific and ripening-regulating regulatory sequences. In addition to a novel method of modifying carbohydrate metabolism, we have also found a novel fructokinase gene. Of the two tomato fructokinase genes described in this invention, one is highly homologous to previously described potato fructokinase gene; the other is highly divergent and represents a kinetically unique plant fructokinase.