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.

喜马拉雅山脉因其独特的气候和地形变化而具有明显的特征；因此，解开原生生命形式的冷适应机制和过程一直是科学界关注的问题。从这个角度看，嗜冷固氮菌Pseudomonas helmanticensis的蛋白质组学反应研究了低温条件。基于 LC-MS 的分析表明，大多数提供冷应激抗性的差异表达蛋白是分子伴侣和冷休克蛋白。参与脯氨酸、多胺、不饱和脂肪酸生物合成、ROS 中和途径和精氨酸降解的酶被上调。然而，参与能量产生氧化途径的蛋白质被数倍下调。除此之外，低温下未表征蛋白质的上调表明P. helmanticensis表达了用于冷适应的新蛋白质。P. helmanticensis 的蛋白质相互作用网络在寒冷环境下，Tif、Tig、DnaK 和 Adk 是参与寒冷适应的关键蛋白质。最后，这项研究记录了冷应激下喜马拉雅嗜冷P. helmanticensis的蛋白质组和蛋白质-蛋白质相互作用网络。