Insights into the Sulfate Transporter Gene Family and Its Expression Patterns in Durum Wheat Seedlings under Salinity

Sulfate transporters (SULTRs) are an essential plant transporter class responsible for the absorption and distribution of sulfur, an essential plant growth element. SULTRs are also involved in processes related to growth and development and in response to environmental stimuli. In the present study, 22 TdSULTR family members were identified and characterized in the genome of Triticum turgidum L. ssp. durum (Desf.) using available bioinformatics tools. The expression levels of candidate TdSULTR genes were investigated under salt treatments of 150 and 250 mM NaCl after several different exposure times. TdSULTRs showed diversity in terms of physiochemical properties, gene structure, and pocket sites. TdSULTRs and their orthologues were classified into the known five main plant groups of highly diverse subfamilies. In addition, it was noted that segmental duplication events could lengthen TdSULTR family members under evolutionary processes. Based on pocket site analysis, the amino acids leucine (L), valine (V), and serine (S) were most often detected in TdSULTR protein binding sites. Moreover, it was predicted that TdSULTRs have a high potential to be targeted by phosphorylation modifications. According to promoter site analysis, the plant bioregulators ABA and MeJA were predicted to affect TdSULTR expression patterns. Real-time PCR analysis revealed TdSULTR genes are differentially expressed at 150 mM NaCl but show similar expression in response to 250 mM NaCl. TdSULTR reached a maximum level of expression 72 h after the 250 mM salt treatment. Overall, we conclude that TdSULTR genes are involved in the response to salinity in durum wheat. However, additional studies of functionality are needed to determine their precise function and linked-interaction pathways.