Identification and Expression Analysis of Tobacco SAUR Gene Family

To elucidate the molecular mechanisms of SAUR gene family in plant growth, development and stress responses, we employed bioinformatics tools to identify the SAUR family genes in tobacco. We analyzed their evolutionary relationships, physicochemical properties, gene and protein structures, promoter elements, chromosomal distribution, and leaf expression patterns. Our results identified 137 NtSAUR genes in tobacco, distributed across 23 chromosomes and classified into 4 subfamilies. Notably, only 4 genes contain introns, and the protein sequences of genes within the same subfamily are highly conserved. The promoters of NtSAUR genes contain four types of cis-acting elements, which are involved in plant growth and development, environmental stress, hormone and light responses. Evolutionary analysis suggests that NtSAUR genes may have undergone extensive tandem duplication and chromosomal fragment duplications. Based on leaf expression patterns analysis, we identified two genes potentially involved in tobacco leaf morphogenesis and six genes likely associated with leaf senescence. These findings provide a theoretical foundation for the subsequent functional verification SAUR genes in tobacco.