Vitamin D(5) in Arabidopsis thaliana

Vitamin D(3) 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(3). Insufficient levels of vitamin D(3) especially in the case of low solar UV-B irradiation is often compensated by an intake of a dietary source of vitamin D(3) of animal origin. Small amounts of vitamin D(3) 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(5) in the model plant Arabidopsis thaliana. This plant secosterol is a UV-B mediated derivative of provitamin D(5), the precursor of sitosterol. The present work will allow a further survey of vitamin D distribution in plant species.