HY4 — Arabidopsis thaliana

Summary

AT4G08920 (HY4, also known as CRYPTOCHROME 1) encodes a protein that belongs to the cryptochrome/DNA photolyase family and possesses FAD binding, blue light photoreceptor activity, and histone kinase activity. In Arabidopsis thaliana, HY4 is associated with blue light reception, hypocotyl growth inhibition, de-etiolation, shoot branching, fruit growth, magnetic field sensitivity, and activation of the psbD light-responsive promoter. The protein localizes to the chloroplast nucleoid, nuclear bodies, cytosol, and plasma membrane, and is linked to phototransduction, circadian behavior, magnetoception, guard cell development, thermomorphogenesis, and pyrimidine dimer repair. HY4 has been connected to numerous agronomic traits including grain yield, leaf chlorophyll content, leaf area, panicle number, flower diameter, photoperiod sensitivity, blue and red light sensitivity, phenolic compound content, and glyphosate sensitivity. Studies of related genes in other species link the cryptochrome family to fruit antioxidant content, fruit weight, plant pigment content, net photosynthetic rate, and resistance to Pseudomonas syringae.