Genome-Wide Analysis of the GRAS Gene Family and Functional Identification of GmGRAS37 in Drought and Salt Tolerance

Abstract

<i>GRAS</i> genes, which form a plant-specific transcription factor family, play an important role in plant growth and development and stress responses. However, the functions of <i>GRAS</i> genes in soybean (<i>Glycine max</i>) remain largely unknown. Here, 117 <i>GRAS</i> genes distributed on 20 chromosomes were identified in the soybean genome and were classified into 11 subfamilies. Of the soybean <i>GRAS</i> genes, 80.34% did not have intron insertions, and 54 pairs of genes accounted for 88.52% of duplication events (61 pairs). RNA-seq analysis demonstrated that most <i>GmGRASs</i> were expressed in 14 different soybean tissues examined and responded to multiple abiotic stresses. Results from quantitative real-time PCR analysis of six selected <i>GmGRASs</i> suggested that <i>GmGRAS37</i> was significantly upregulated under drought and salt stress conditions and abscisic acid and brassinosteroid treatment; therefore, this gene was selected for further study. Subcellular localization analysis revealed that the GmGRAS37 protein was located in the plasma membrane, nucleus, and cytosol. Soybean hairy roots overexpressing <i>GmGRAS37</i> had improved resistance to drought and salt stresses. In addition, these roots showed increased transcript levels of several drought- and salt-related genes. The results of this study provide the basis for comprehensive analysis of <i>GRAS</i> genes and insight into the abiotic stress response mechanism in soybean.