Functional Analysis of Arabidopsis thaliana Galactinol Synthase AtGolS2 in Response to Abiotic Stress

Soil salt-alkalization is one of the adverse factors limiting crop yields. Identification of key salt-alkaline tolerant genes is of great significance for molecular breeding of stress-resistant crops. In this study, a T-DNA insertion Arabidopsis mutant atgols2 showing higher sensitivity to bicarbonate salt-alkaline stress was screened out against NaHCO3 treatment. Further bioinformatic analysis revealed that the AtGolS2 gene encoded a galactinol synthase, which is a member of the glycosyltransferase family A superfamily. We predicted the protein interaction network of AtGolS2 via SMART online analysis, and found that these AtGolS2 interacting proteins were related to lipid metabolism, galactose biosynthesis and raffinose biosynthesis, and participated in abiotic stress responses. By using the online expression data, we showed that AtGolS2 expression responded to salt, osmotic, drought and ABA stress. PCR amplification by using the three primers method verified the homozygous T-DNA insertion in atgols2. Phenotypic assays further uncovered that atgols2 mutant was more sensitive to high salt, osmotic and ABA stresses than the wild type Arabidopsis. Taken together, results in this study revealed the positive function of AtGolS2 in bicarbonate salt-alkaline, high salt, osmotic and ABA stresses, which will facilitate further research regarding the function and molecular mechanism of the GolS family genes in stress responses.