Genome-Wide Identification and Characterization of Gene Family in Foxtail Millet ( L.).

The genes encode signaling peptides that play important roles in various developmental and physiological processes. However, the systematic identification and characterization of genes in foxtail millet ( L.) remain limited. In this study, we identified and characterized 41 genes in the foxtail millet genome. These genes were distributed across nine chromosomes and classified into four groups, with five pairs resulting from gene duplication events. genes within the same phylogenetic group shared similar gene structure and motif patterns, while 34 genes were found to be single-exon genes. All SiCLE peptides harbored the conserved C-terminal CLE domain, with highly conserved positions in the CLE core sequences shared among foxtail millet, Arabidopsis, rice, and maize. The genes contained various -elements, including five plant hormone-responsive elements. Notably, 34 genes possessed more than three types of phytohormone-responsive elements on their promoters. Comparative analysis revealed higher collinearity between genes in maize and foxtail millet, which may be because they are both C plants. Tissue-specific expression patterns were observed, with genes within the same group exhibiting similar and specific expression profiles. and , classified in Group D, displayed relatively high expression levels in all tissues except panicles. Most genes exhibited low expression levels in young panicles, while , , , and showed higher expression in young panicles, with down-regulated during later panicle development. Greater numbers of genes exhibited higher expression in roots, with , , and showing the highest levels and significantly down-regulated after abscisic acid (ABA) treatment. Following treatments with ABA, 6-benzylaminopurine (6-BA), and gibberellic acid 3 (GA3), most genes displayed down-regulation followed by subsequent recovery, while jasmonic acid (JA) and indole-3-acetic acid (IAA) treatments led to upregulation at 30 min in leaves. Moreover, identical hormone treatments elicited different expression patterns of the same genes in leaves and stems. This comprehensive study enhances our understanding of the gene family and provides a foundation for further investigations into the functions and evolution of genes in foxtail millet.