Genome-Wide Identification and Expression Analysis of GRAS Gene Family in Nicotiana tabacum L.

GRAS proteins are a plant-specific protein family that play essential roles in various physiological processes, including plant growth, development and responses to biotic and abiotic stresses. In this study, 95 tobacco GRAS genes were identified by using comparative genomics and bioinformatics. Of these, 50 GRAS family members were unevenly distributed across 20 chromosomes. Phylogenetic analysis, collinearity analysis, and expression pattern examination were performed on these tobacco GRAS genes. Results showed that the newly identified GRAS genes from tobacco and Arabidopsis could be divided into eight subgroups. A total of 26 GRAS members originated from genome-wide replication events, with 16 covariance pairs predicted to be associated with Arabidopsis thaliana GRAS genes. The GRAS genes promoters contain numerous development- and stress-related cis-elements. The expression of these genes showed tissue specificity, and some GRAS members exhibited altered expression levels under drought and salt stress treatments, suggesting their involvement in the signal transduction pathways associated with tobacco’s stress responses.