| Summary: | Stress-associated proteins (SAP), a class of zinc-finger proteins, have been identified as novel stress regulatory proteins in stress responses. However, <i>SAP</i> genes in eggplant (<i>SmSAP</i>) have been little reported. It has important significance in identifying SAP members, understanding the molecular mechanisms underlying stress responses, and tolerance. We performed a comprehensive study of the A20/AN1 domains, motifs, gene structures, phylogenetic relationships, chromosomal locations, gene replications, collinearity, cis-acting elements, and expression pattern responses to various abiotic stresses. Twenty-one <i>SAP</i> genes were identified in eggplant (<i>SmSAP</i>) and were localized on 10 chromosomes. A phylogenetic analysis revealed that most of the SmSAP proteins showed a high homology with the tomato SAP members, and 21 members were divided into four groups based on the homology of the SAP members in eggplant, tomato, rice, and <i>Arabidopsis</i>. Further analysis revealed that SmSAP proteins contain the characteristic A20/AN1 domains, the A20 domain composed of motif 2 (ILCINNCGFFGSPATMNLCSKCYKDMJLK). Four pairs of tandem duplications were found in eggplant, and 10 <i>SmSAP</i> genes had collinearity with <i>SAP</i> genes from <i>Arabidopsis</i>, potato, or tomato, but only four <i>SmSAP</i> genes were collinear with <i>SAP</i> genes in the three species mentioned above. Moreover, the promoters of <i>SmSAP</i> genes were predicted to contain many cis-acting elements that respond to abiotic stress and hormones. A qRT-PCR analysis of the four selected <i>SmSAP</i> genes exhibited diverse expression levels in response to various environmental stresses. These results provided a comprehensive analysis of the <i>SmSAP</i> genes and lay a solid foundation for improving the understanding of the functional diversification of <i>SAP</i> genes under various environmental stresses in eggplant.
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