Evolutionary and expression analysis of sugar transporters from Tartary buckwheat revealed the potential function of FtERD23 in drought stress

Drought is becoming a common threat to crop production. Identifying and utilizing excellent drought-resistant genes is crucial to combating this stress and ensuring global food security by developing drought-resistant crop varieties. Although sugar transporters are involved in stress tolerance in many plants, the sugar transporter gene family of Tartary buckwheat has yet to be systematically analyzed. This study identified 140 sugar transporter genes from the ‘Pinku’ Tartary buckwheat genome and classified them into 10 subfamilies. Structural analysis showed that subfamily SGB/pGlcT had the highest number of introns compared to other subfamilies, and abundant abiotic stress-related cis-acting elements existed in the promoter region. Collinear analysis revealed relatively ancient genes FtSUT7, FtSTP28, FtPLT1, and FtINT2. The expression of sugar transporter genes was screened under various abiotic stresses, which revealed the association of stress tolerance with different sugar transporter genes, i.e., FtERD23, FtINT2, FtpGlcT2, and FtSTP27. Further, we observed that the overexpression of FtERD23 maintains osmotic pressure through glucose transport, which may enhance drought stress tolerance. Moreover, gene co-expression analyses using weighted gene co-expression network analysis (WGCNA) and fuzzy c-means algorithm (FCMA) identified six transcription factors that may regulate FtERD23 expression and are involved in plant drought tolerance. Our systematic analysis provides a theoretical basis for the further functional characterization of sugar transporter genes to improve drought tolerance in Tartary buckwheat and its related species.