Comparative Analysis on the Evolution of Flowering Genes in Sugar Pathway in Brassicaceae.

Sugar plays an important role in regulating the flowering of plants. However, studies of genes related to flowering regulation by the sugar pathway of Brassicaceae plants are scarce. In this study, we performed a comprehensive comparative genomics analysis of the flowering genes in the sugar pathway from seven members of the Brassicaceae, including: <i>Arabidopsis thaliana</i>, <i>Arabidopsis lyrata</i>, <i>Astelia pumila</i>, <i>Camelina sativa</i>, <i>Brassica napus</i>, <i>Brassica oleracea</i>, and <i>Brassica rapa</i>. We identified 105 flowering genes in the sugar pathway of these plants, and they were categorized into nine groups. Protein domain analysis demonstrated that the <i>IDD8</i> showed striking structural variations in different Brassicaceae species. Selection pressure analysis revealed that sugar pathway genes related to flowering were subjected to strong purifying selection. Collinearity analysis showed that the identified flowering genes expanded to varying degrees, but <i>SUS4</i> was absent from the genomes of <i>Astelia pumila</i>, <i>Camelina sativa</i>, <i>Brassica napus</i>, <i>Brassica oleracea</i>, and <i>Brassica rapa</i>. Tissue-specific expression of <i>ApADG</i> indicated functional differentiation. To sum up, genome-wide identification revealed the expansion, contraction, and diversity of flowering genes in the sugar pathway during Brassicaceae evolution. This study lays a foundation for further study on the evolutionary characteristics and potential biological functions of flowering genes in the sugar pathway of Brassicaceae.