HY5, a positive regulator of light signaling, negatively controls the unfolded protein response in Arabidopsis

Significance In nature, plants are inevitably exposed to adverse conditions such as salinity, drought, and extreme temperatures. Recent reports suggest that environmental stresses critically affect the protein-folding capacity of endoplasmic reticula (ER), leading to ER stress. As the growth and development of plants significantly depend on light environment, the crosstalk between light signaling and ER stress response explained in current research can be a unique feature of plants. Our results suggest that light increases the ER stress sensitivity of plants and ELONGATED HYPOCOTYL 5, a positive regulator of light signaling, negatively regulates unfolded protein response gene expression in plant cells, which decreases the protein-folding capacity. The present study may form the basis for designing new strategies to increase stress tolerance of plants by tightly controlling light environment.