Abstract: Selenium plays a very important physiological and biochemical role in plants, selenates are actively transported by SULTR carrier proteins. SiSULTR2.1 gene sequence was identified from the millet genome database, bioinformatics analysis of SiSULTR2.1 was performed and expression response of leaves sprayed with Na2SeO4 and Na2SO4 was analyzed. The objective of this study was to investigate the physicochemical properties of SiSULTR2.1 gene and its expression response to Na2SeO4 and Na2SO4 treatment in millet, and to provide theoretical basis for the study of selenium and sulfur transport mechanism of SiSULTR2.1 gene in millet. SiSULTR2.1 was hydrophobic, non-secretory protein, without signal peptide, 70 374.55 Da molecular weight, 656 amino acids and its secondary structure is composed of α-helix, β-folding and random crimp, contains STAS domain and sulfate-transp domain that are characteristic of sulfur transporter. Quantitative real-time PCR (qRT-PCR) analysis showed that SiSULTR2.1 has obvious tissue expression specificity, with the higher expression level in the stems and leaves. SiSULTR2.1 could be detected in all tested tissues of millet plant and expression was induced by Na2SeO4 and Na2SO4 for 0 ～ 96 h, SiSULTR2.1 has a faster response to Na2SO4, reaching its peak at 12 h, and a slower response to Na2SeO4. The results would provide a basis for further elucidating the mechanism of SiSULTR2.1 gene in Se and S transport.
Key words: millet; sulfate transporter; expression analysis; Na2SeO4; Na2SO4
（Acta Laser Biology Sinica, 2022, 31(2): 157-164）