Genome-wide characterization of the wheat cryptochrome/photolyase family identifies TaCRY1b as a lamina-joint-associated protein interacting with TaLG2 and TaLG2L
Background Cryptochromes (CRYs) are blue light and ultraviolet A (UV-A) photoreceptors that play pivotal roles in regulating plant development and stress responses through mediating light signaling pathways. However, the evolutionary and functional characteristics of the cryptochrome/photolyase (CRY/PHL) family in wheat (Triticum aestivum L.) remain poorly understood. Results 57 CRY/PHL genes were identified across eight species, including 14 members in hexaploid wheat. Phylogenetic analysis classified CRY/PHLs into four subfamilies. All TaCRY/PHL proteins contain the conserved photolyase homology region (PHR), whereas the cryptochrome C-terminal (CCT) domain is exclusively present in the CRY1 subfamilies. Collinearity analysis revealed extensive synteny among wheat, rice, and maize CRY/PHLs, but not with Arabidopsis, indicating lineage-specific evolution within grasses. Promoters of TaCRY/PHL genes contain multiple predicted light-, hormone-, and stress-responsive cis-elements. Tissue-specific expression profiling demonstrated that subfamily A and C members are predominantly expressed in vegetative tissues, while subfamily B and D members are mainly expressed in reproductive organs. Notably, TaCRY1b expression progressively increased during leaf lamina joint (LJ) development. Subcellular localization demonstrated that TaCRY1b localizes to both the nucleus and cytoplasm, while bimolecular fluorescence complementation assays uncovered direct physical interactions between TaCRY1b and TaLiguless2 (TaLG2s), key regulators of LJ formation. AlphaFold3 prediction showed a putative interaction interface between TaLG2/TaLG2L and TaCRY1b, where multiple complementary residue pairs form polar contacts predominantly within the PHR domain of TaCRY1b. Conclusions This study provides a comprehensive framework for the evolution and functional diversification of the wheat CRY/PHL family and identifies TaCRY1b as a promising candidate regulator of lamina joint development, laying a solid foundation for further investigations into its moltcular function in leaf angle modulation.