In vivo evaluation of transgenic watercress containing gene encoding Escherichia coli heat-labile toxin B subunit

In this work, the characterizations of the LTB (Escherichia coli heat-labile toxin B subunit) transgenic watercresses through Agrobacterium tumefaciens-mediated transformation (A1 and A3-A5) and by using biolistic method (B1 and B4) were investigated. Generally, their growth is not remarkably different from the wild-type. Their physiological and biochemical characteristics are relatively different in which plant A1 has highest values such as pigment (0.92 mg g⁻¹), photosynthetic rate (23.39 mgCO₂ [dm²]⁻¹ h⁻¹), dry matter (7.42 %), vitamin C (0.34 mg g⁻¹), calcium (0.83 mg g⁻¹), and potassium (2.47 mg g⁻¹). The dry matter and calcium of all the transgenic watercresses and the wild-type are the same content. Southern blot hybridization showed the transgenic plants contain 1–2 copies in the genome. LTB protein strongly expresses in all the transgenic plants with contents from 1.16 to 1.46 % of total soluble protein. The GM1-ELISA binding assay indicated that plant-derived LTB protein bound to GM1-ganglioside receptors.