Genome-Wide Analysis of Gene Family in Three Species Provides Insights into Expression Patterns under Hormonal and Salt Stresses.

BBX protein is a class of zinc finger transcription factors that have B-box domains at the N-terminus, and some of these proteins contain a CCT domain at the C-terminus. It plays an important role in plant growth, development, and metabolism. However, the expression pattern of BBX genes in alfalfa under hormonal and salt stresses is still unclear. In this study, we identified a total of 125 gene family members by the available reference genome in diploid alfalfa ( spp. ), a model plant (), and tetraploid alfalfa (. ), and divided these members into five subfamilies. We found that the conserved motifs of of the same subfamily reveal similarities. We analyzed the collinearity relationship and duplication mode of these genes and found that the expression pattern of genes is specific in different tissues. Analysis of the available transcriptome data suggests that some members of the gene family are involved in multiple abiotic stress responses, and the highly expressed genes are often clustered together. Furthermore, we identified different expression patterns of some genes under salt, ethylene, salt and ethylene, salicylic acid, and salt and salicylic acid treatments, verified by qRT-PCR, and analyzed the subcellular localization of , , and using transient expression in tobacco. The results showed that genes were localized in the nucleus. This study systematically analyzed the gene family in plants, which provides a basis for the study of gene family tolerance to abiotic stresses.