UV-B induced accumulation of tocopherol in Arabidopsis thaliana is not dependent on individual UV photoreceptors

Tocopherols are lipophilic antioxidants in plants. Their potential role in protecting UV-B exposed plants has been alluded to, but not shown. Here we have determined UV-B induced accumulation of tocopherol in the model plant Arabidopsis thaliana and asked (1) whether induction relies on UV-B application duration, (2) if UV (UVR8) or blue light (phototropins or cryptochrome) photoreceptors mediate the accumulation of tocopherol and, (3) whether tocopherol contributes to UV-B photoprotection. Results show that UV-B induces accumulation of tocopherols in plants, with the strongest induction of alpha-tocopherol. The induction is dependent on exposure duration but not individual photoreceptors. Plants with impaired tocopherol biosynthesis show no UV-B induction of tocopherol and are found to be UV-sensitive. Overall, the results show for the first time that tocopherol accumulation is a component of UV-B acclimation and that impeding their responses leads to increased UV-susceptibility of the photosynthetic machinery.