Tomato is a suitable material for producing recombinant miraculin protein in genetically stable manner

Miraculin is a taste-modifying protein that turns sour tastes into sweet ones. We previously generated transgenic tomato plants that constitutively expressed miraculin. To study the stability of transgene inheritance and expression in detail, three lines of transgenic tomato that highly accumulate miraculin in the T0 generation with a single copy of the miraculin gene were analyzed for genomic organization, mRNA expression and miraculin accumulation up to the T5 generation, corresponding to six generations of propagation. Transgenes were stably inherited and genomic rearrangement was not detected; this was confirmed in the T5 generation in one line and the T3 generation in the other two lines. The expression of miraculin mRNA was stable through multiple generations and in individual plants of the same generation. The concentrations of miraculin protein ranged from 8.73 to 11.52 μg/mg total soluble protein in the transgenic tomatoes, and they were stable in each line. These results suggest that the tomato is a suitable material for producing recombinant miraculin protein.