Genome-Wide Identification of the Gene Family in Pepper () and Its Expression Profiles During Seed Germination.

The () family plays key regulatory roles in seed dormancy and germination. However, a genome-wide analysis of genes has not been performed for pepper (), one of the agriculturally important species, and no studies have been conducted to characterize their expression profiles. Based on genome information, the identification and expression analysis of gene family members through bioinformatics approaches can provide a theoretical foundation for subsequent studies on the biological functions of and the improvement of seed traits in breeding. In this study, a total of 13 genes were identified in the genome. Phylogenetic analysis showed that these CaDOG1s, along with DOG1s from thale cress (), rice (), and maize (), were classified into four subgroups. All genes were unevenly distributed on six chromosomes, and they had relatively conserved exon-intron patterns, most with zero to one intron. According to the chromosomal distribution patterns and synteny analysis of the genes, the family expanded mainly through replication, which occurred predominantly after the divergence of dicotyledons and monocotyledons. Conserved motif analysis indicated that all encoded proteins contained Motif 2 and Motif 6, except for CaDOG1-3. Expression profile analysis using transcriptome data revealed that genes were differentially expressed across various tissues and developmental stages, with notable involvement in flowers and seeds. Quantitative real-time PCR also revealed that all genes were downregulated during seed germination, indicating that may play negative roles in seed germination. Moreover, upon abscisic acid treatment, six genes exhibited upregulation, while in response to ethylene, four genes exhibited downregulation. Taken together, these findings provide an extensive description of the gene family and might facilitate further studies for elucidating their functions in seed germination.