Ethylene signaling may be involved in the regulation of tocopherol biosynthesis in Arabidopsis thaliana.

Tocopherol biosynthesis was investigated in ein3-1, etr1-1 and eto1-1 mutants of Arabidopsis thaliana, which show a defect in ethylene signaling, perception and over-produce ethylene, respectively. A mutation in the EIN3 gene delayed the water-stress related increase in alpha-tocopherol and caused a reduction in the levels of this antioxidant by ca. 30% compared to the wild type. In contrast to the wild type and ein3-1 mutants, both etr1-1 and eto1-1 mutants showed a sharp (up to 5-fold) increase in alpha-tocopherol levels during leaf aging. It is concluded that ethylene perception and signaling may be involved in the regulation of tocopherol biosynthesis during water stress and leaf aging.