Structural assembly of maize CRY-GL2 photosignaling complex provides insights into its regulatory role in cuticular wax biosynthesis

Plant cryptochromes (CRYs) are blue-light photoreceptors regulating physiological processes via oligomerization-dependent interaction with effectors. However, the structural basis for photoactivated CRY-effector assembly remains elusive. Here, we report the crystal structure of an active maize CRY1c photolyase homology region in complex with GLOSSY2 (ZmGL2), a BAHD acyltransferase family protein that could form an enzyme complex with ECERIFERUM6 (ZmCER6) and direct very-long-chain fatty acid elongation in cuticular wax biosynthesis. Light-activated CRY1c forms a homotetrameric scaffold. Each protomer binds one ZmGL2 molecule via conformational changes, forming a 4:4 hetero-octameric photosignaling complex. Structural alignment shows 78% overlap between the GL2-binding interfaces in the ZmCRY1c-ZmGL2 and ZmCER6-ZmGL2 complexes. Biochemically, CRY1c dose-dependently inhibits ZmCER6-ZmGL2 enzyme activity, unveiling a light-dependent regulatory switch modulating very-long-chain fatty acid elongation efficiency. Our work establishes the atomic model for light-activated CRY-effector assembly and uncovers spatial competition between photoreceptor and metabolic enzyme complexes as a photoregulatory paradigm in wax biosynthesis.