Differential proteomic expression of himalayan psychrotrophic diazotroph Pseudomonas palleroniana N26 under low temperature diazotrophic conditions.

ABSTRACT

BACKGROUND: In low temperature nitrogen-deficient ecosystems, native microorganisms must possess adaptive mechanisms to cope with environmental stress as well as nitrogen (N) starvation-like conditions. However, moderate information is available about the cold adapted diazotrophs and diazotrophy. OBJECTIVE: The aim of this study was to examine the proteomic response(s) of Himalayan psychrotrophic diazotroph under low temperature nitrogen fixing conditions. MATERIALS AND METHODS: Proteomic analysis of Pseudomonas palleroniana N26 was carried out using two dimensional electrophoresis technique. RESULTS: Altogether, fifty three protein spots were found to be differentially expressed revealing several mechanisms thought to be involved in low temperature adaptation and nitrogen fixation, including general stress adaptation, protein synthesis and modifications, and energy metabolism. Expression profiling of the spots revealed the up-regulation of low molecular weight acidic proteins; a majority of which were stress proteins. The largest group of down-regulated proteins were related to biosynthetic processes; thereby, providing the evidence for stress-associated metabolic adaptations. CONCLUSION: The present study, which provides an overview of the cold diazotrophy of a Himalayan psychrotrophic bacterium and its adaptive responses, can facilitate further studies of low temperature nitrogen fixing mechanisms, psychrophilic diazotrophic markers, and transgenic microorganism(s)/crop(s) development.