Cloning and in silico characterization of an abiotic stress-inducible U-box domain-containing protein gene GsPUB8 from Glycine soja

The ubiquitination pathway is involved in the posttranslational modification of cellular proteins. However, the role of E3 ubiquitin ligase family proteins under abiotic stress conditions remains unclear, particularly in soybean. The core objective of the current study was to isolate and functionally characterize the GsPUB8 protein gene from wild soybean (Glycine soja) by using a homologous cloning method to investigate its abiotic stress responses. The GsPUB8 is a 40,562 Da molecular weight protein with 373 amino acid residues. The sequence alignment revealed the presence of U-box domain while the phylogenetic analysis showed an abundance of PUB8 proteins in both monocot and dicot plants. Analysis of gene structure predicted the absence of introns along with the presence of one exon. Furthermore, the activity of the GsPUB8 protein was anticipated in the plasma membrane and its expression was persuaded with NaCl, ABA, PEG6000, and NaHCO3 treatments with considerably higher manifestation in roots than leaves although, expressed in both vegetative and reproductive parts of G. soja. GsPUB8 protein showed 54% and 32% sequence identity to U-box domain containing 8 and 12 proteins from Arabidopsis thaliana and Oryza sativa subsp. japonica, respectively. GsPUB8 exhibited relatively higher expression under saline and drought stress particularly in roots. Whereas, the 3D model of GsPUB8 protein was generated using the SWISS-MODEL. This study can be used to manipulate the GsPUB8 protein or GsPUB8 gene for transformation purposes and its functional characterization under abiotic stress conditions.