Genome-wide identification of the LEA gene family in Chimonanthus praecox and functional analysis of CpLEA3-5 involved in cold stress

Late embryogenesis abundant (LEA) proteins often accumulate in seeds at the late stage of embryogenesis, which play a crucial role in the plant stress response. In this study, a genome-wide investigation of LEA genes in wintersweet ( Chimonanthus praecox ) was performed based on characterization of conserved domains and sequence motifs using bioinformatics approaches. A total of 65 CpLEA genes were identified in C. praecox , which were classified into eight groups based on phylogenetic analysis, including LEA1–6 , SMP , and dehydrin ( DHN ). Further analysis revealed that collinear genes within this family have been shaped by purifying selection over a span ranging from 88.7 to 242.2 million years ago. Transcriptome analysis of C. praecox flowers suggested that CpLEA genes appear to be involved in the differentiation of floral buds and cold tolerance. Transcripts of seven CpLEA3 subfamily genes, including CpLEA3–5 , were predominantly detected following low-temperature treatment. CpLEA3–5 protein was primarily localized in the nucleus. Overexpression of CpLEA3–5 in Arabidopsis thaliana promoted early flowering and improved the low-temperature tolerance of transgenic plants by influencing the expression of related endogenous genes. Activity of the CpLEA3–5 promoter increased with the treatment of multiple hormones. Overall, this study indicates that CpLEA3–5 plays a significant role in the flowering and cold tolerance of wintersweet. • In Chimonanthus praecox , 65 LEA genes have been identified, classified into 8 subfamilies. • Analysis suggests that CpLEAs may be involved in plant flowering. • The expression levels of CpLEAs significantly increase after exposure to extreme temperatures and other stress treatments. • CpLEA3–5 enhances the low-temperature tolerance of transgenic Arabidopsis.