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. To combat this stress and ensure global food security, the identification and utilization of excellent drought-resistant genes are crucial for developing drought-resistant crop varieties. However, sugar transporters are known to be involved in stress tolerance in many plants, while the sugar transporter gene family of Tartary buckwheat has not been systematically analyzed yet. In this study, 140 sugar transporter genes were identified from the 'Pinku' Tartary buckwheat genome and classified into ten 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 that FtSUT7, FtSTP28, FtPLT1, and FtINT2 genes are relatively ancient. 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, it was observed that the overexpression of FtERD23 maintains osmotic pressure through glucose transport, which may enhance drought stress tolerance. Moreover, gene co-expression analyses using WGCNA and FCMA identified six transcription factors that may regulate FtERD23 expression and are involved in plant drought tolerance. In summary, this systematic analysis provides a theoretical basis for further functional characterization of sugar transporter genes to improve drought tolerance in Tartary buckwheat and its related species.