Vitamin D₅ in Arabidopsis thaliana

Vitamin D₃ is a secosterol hormone critical for bone growth and calcium homeostasis, produced in vertebrate skin by photolytic conversion of the cholesterol biosynthetic intermediate provitamin D₃. Insufficient levels of vitamin D₃ especially in the case of low solar UV-B irradiation is often compensated by an intake of a dietary source of vitamin D₃ of animal origin. Small amounts of vitamin D₃ were described in a few plant species and considered as a peculiar feature of their phytochemical diversity. In this report we show the presence of vitamin D₅ in the model plant Arabidopsis thaliana. This plant secosterol is a UV-B mediated derivative of provitamin D₅, the precursor of sitosterol. The present work will allow a further survey of vitamin D distribution in plant species.