Vitamin D in Arabidopsis thaliana.

Vitamin D is a secosterol hormone critical for bone growth and calcium homeostasis, produced in vertebrate skin by photolytic conversion of the cholesterol biosynthetic intermediate provitamin D. Insufficient levels of vitamin D especially in the case of low solar UV-B irradiation is often compensated by an intake of a dietary source of vitamin D of animal origin. Small amounts of vitamin D 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 D in the model plant Arabidopsis thaliana. This plant secosterol is a UV-B mediated derivative of provitamin D, the precursor of sitosterol. The present work will allow a further survey of vitamin D distribution in plant species.