Plant adaptation to abiotic stress is significantly influenced by galactinol synthase (GolS), which is a regulatory enzyme that catalyzes the synthesis of raffinose family oligosaccharides (RFOs). Soybean GolS genes, GmGolS2-1 and GmGolS2-2 were isolated in this study. GmGolS2-1 was 993 bp and encoded a 330-amino acid polypeptide, and GmGolS2-2 was 975 bp and encoded a 324-amino acid polypeptide. The deduced amino acid sequences contained common features of plant GolS proteins: a DXD motif and a hydrophobic pentapeptide (APSAA). Significant increase of GmGolS2-1 and GmGolS2-2 transcripts under drought stress was observed under real-time fluorescence quantitative PCR (qPCR), while their transcripts only increased slightly under salt and cold stresses. The GmGolS2-1 promoter region contained four methyl jasmonate-responsive elements, two anaerobic-induced elements, a wound-responsive element, and two MYB binding sites. Overexpression of GmGolS2-1 enhanced the GolS activity along with expression of stress-associated genes in transgenic tobacco. Additionally, the overexpression of GmGolS2-1 resulted in lower relative electrolyte leakage and malondialdehyde (MDA) content and higher soluble carbohydrates and proline content in transgenic tobacco than wild-type (WT) tobacco under drought stress. These findings indicate that GmGolS2-1 improved transgenic tobacco drought resistance.

半乳糖醇合酶（GolS）是一种可催化棉子糖家族寡糖（RFOs）合成的调节酶，对植物对非生物胁迫的适应性有显着影响。本研究分离了大豆GolS基因GmGolS2-1和GmGolS2-2。GmGolS2-1为993 bp，编码330个氨基酸的多肽，而GmGolS2-2为975 bp，编码324个氨基酸的多肽。推导的氨基酸序列包含植物GolS蛋白的共同特征：DXD基序和疏水性五肽（APSAA）。GmGolS2-1和GmGolS2-2显着增加在实时荧光定量PCR（qPCR）下观察到干旱胁迫下的转录本，而在盐和冷胁迫下它们的转录本仅略有增加。该GmGolS2-1启动子区域包括下列四个茉莉酸甲酯响应元件中，两个厌氧诱导的元件，伤口响应元件，和两个MYB结合位点。GmGolS2-1的过表达增强了转基因烟草中Gol​​S的活性以及与压力相关基因的表达。另外，在干旱胁迫下，GmGolS2-1的过表达导致转基因烟草中的相对电解质泄漏和丙二醛（MDA）含量降低，可溶性碳水化合物和脯氨酸含量更高。这些发现表明GmGolS2-1改善了转基因烟草的抗旱性。