Abstract
In plants, tocopherols (vitamin E) have long been assumed to protect photosynthetic membranes from oxidative stress by acting as lipid-soluble antioxidants. However, this hypothesis has not been rigorously tested. Here we subjected and analyzed the response of a series of Arabidopsis vitamin E-deficient (vte) mutants to various abiotic stresses. Surprisingly, these mutants were virtually identical to wild-type during high light, salinity and drought stresses. Also, the photosynthetic response of these mutants did not differ significantly from wild-type during high light stress, suggesting tocopherols have a limited photoprotective role in plants. In contrast, these mutants exhibited a dramatic chilling susceptible phenotype; the mutant in comparison to wild-type grew slower, accumulated anthocyanins in mature leaves, and produced less seeds during the treatment. Detail biochemical characterization of the phenotype provided evidence that tocopherols play a critical role in chilling adaptation by affecting carbohydrate metabolism, which is independent of photoprotective function of tocopherols.
