Positively Selected Orthologous Genes Identified in Sesame (Sesamum indicum) by Deep Resequencing

Sesame (Sesamum indicum L.) is the queen of oil seed crops and is cultivated widely in tropical and subtropical areas. The availability of the sesame genome sequence presents unprecedented opportunities for studying its genetics, genomics, and evolution. In this report, we conducted a genome resequencing-based identification of sesame orthologs; in total, 26,379 coding sequences (CDSs) were isolated. Using a reciprocal best hit, we ultimately identified a total of 639 orthologs sets after one-to-one orthologs extraction across seven Pentapetalae plant species. These orthologs were considered to be the most credible between the two species, and in sesame. Furthermore, we performed a branch model-based maximum likelihood estimation of dN/dS of the orthologs, resulting in the identification of 198 evolutionarily accelerated orthologs and 66 positively selected genes (P-value and FDR ＜ 0.05). An enrichment analysis and protein interaction network suggested 19 genes with important functions of the orthologs specific in sesame development and domestication. The method we used here provides a case study for identifying orthologous genes between sesame and other plants species that are distributed in equilibrium phylogenetically, which can be used in other plants.