Yeast profilin complements profilin deficiency in transgenic tomato fruits and allows development of hypoallergenic tomato fruits

Abstract

Gene silencing of Lyc e 1 leads to reduced allergenicity of tomato fruits but impaired growth of transgenic tomato plants. The aim of the study was to restore growth of Lyc e 1-deficient tomato plants while retaining reduced allergenicity by simultaneous complementation of profilin deficiency by expression of nonallergenic yeast profilin. Transgenic plants were generated and tested by RT-PCR and immunoblotting; allergenicity of yeast profilin and transgenic fruits was investigated by IgE binding, basophil activation, and skin-prick tests. Lyc e 1 content of transgenic tomato fruits was <5% of that of wild-type plants, causing significantly reduced IgE antibody binding. Simultaneous coexpression of yeast profilin restored growth and biomass production almost to wild-type levels. Yeast profilin, sharing 32.6% amino acid sequence identity with Lyc e 1, displayed low IgE-binding capacity and allergenic potency. Among 16 tomato-allergic patients preselected for sensitization to Lyc e 1, none showed significant reactivity to yeast profilin. Yeast profilin did not induce mediator release, and coexpression of yeast profilin did not enhance the allergenicity of Lyc e 1-reduced fruits. Simultanous coexpression of yeast profilin allows silencing of tomato profilin and generation of viable plants with Lyc e 1-deficient tomato fruits. Therefore, a novel approach to allergen avoidance, genetically modified foods with reduced allergen accumulation, can be generated even if the allergen fulfills an essential cellular function in the plant. In summary, our findings of efficiently complementing profilin-deficient tomato plants by coexpression of low allergenic yeast profilin demonstrate the feasibility of creating low-allergenic food even if the allergen fulfills essential cellular functions.