Abstract
Himalayan mountains are distinctly characterized for their unique climatic and topographic variations; therefore, unraveling the cold-adaptive mechanisms and processes of native life forms is always being a matter of concern for scientific community. In this perspective, the proteomic response of psychrophilic diazotroph Pseudomonas helmanticensis was studied towards low-temperature conditions. LC-MS-based analysis revealed that most of the differentially expressed proteins providing cold stress resistance were molecular chaperons and cold shock proteins. Enzymes involved in proline, polyamines, unsaturated fatty acid biosynthesis, ROS-neutralizing pathways, and arginine degradation were upregulated. However, proteins involved in the oxidative pathways of energy generation were severalfold downregulated. Besides these, the upregulation of uncharacterized proteins at low temperature suggests the expression of novel proteins by P. helmanticensis for cold adaptation. Protein interaction network of P. helmanticensis under cold revealed that Tif, Tig, DnaK, and Adk were crucial proteins involved in cold adaptation. Conclusively, this study documents the proteome and protein-protein interaction network of the Himalayan psychrophilic P. helmanticensis under cold stress.