The Role of Vitamin D inEmiliania huxleyi: A Microalgal Perspective on UV-B Exposure

Abstract

AbstractAn essential interaction between sunlight and eukaryotes involves the production of vitamin D through exposure to ultraviolet-B (UV-B) radiation. While extensively studied in vertebrates, the role of vitamin D in non-animal eukaryotes like microalgae remains unclear.Emiliania huxleyi, a microalga inhabiting shallow ocean depths exposed to UV-B radiation, is well-suited for this research. Our results show thatE. huxleyican produce vitamin D2and D3, pointing to their potential role in the algal physiology. We further show thatE. huxleyialgae respond to vitamin D at the transcriptional level, regulating the expression of protective mechanisms such as the light-harvesting complex stress-related protein (LHCSR) and heme oxygenase, and that vitamin D enhances the algal photosynthetic performance while reducing harmful reactive oxygen species buildup. Understanding the function of vitamin D inE. huxleyihas broader implications, shedding light on its role in non-animal eukaryotes and its potential importance in marine ecosystems. This research sets the stage for further investigations into the complex relationship between sunlight, vitamin D, and microalgal physiology, which contributes to our understanding of how eukaryotes adapt to diverse environmental conditions.