Multilocus sequence based identification and adaptational strategies of Pseudomonas sp. from the supraglacial site of Sikkim Himalaya

Abstract

Microorganisms inhabiting the supraglacial ice are biotechnologically significant as they are equipped with unique adaptive features in response to extreme environmental conditions of high ultraviolet radiations and frequent freeze-thaw. In the current study, we obtained eleven strains of Pseudomonas from the East Rathong supraglacial site in Sikkim Himalaya that showed taxonomic ambiguity in terms of species affiliation. Being one of the most complex and diverse genera, deciphering the correct taxonomy of Pseudomonas species has always been challenging. So, we conducted multilocus sequence analysis (MLSA) using five housekeeping genes, which concluded the taxonomic assignment of these strains to Pseudomonas antarctica. This was further supported by the lesser mean genetic distances with P. antarctica (0.73%) compared to P. fluorescens (3.65%), and highest ANI value of ~99 and dDDH value of 91.2 of the representative strains with P. antarctica PAMC 27494. We examined the multi-tolerance abilities of these eleven Pseudomonas strains. Indeed the studied strains displayed significant tolerance to freezing for 96 hours compared to the mesophilic control strain, while except for four strains, seven strains exhibited noteworthy tolerance to UV-C radiations. The genome-based findings revealed many cold and radiation resistance-associated genes that supported the physiological findings. Further, the bacterial strains produced two or more cold-active enzymes in plate-based assays. Owing to the polyadaptational attributes, the strains ERGC3:01 and ERGC3:05 could be most promising for bioprospection.

Bacterial community distribution and functional potentials provide key insights into their role in the ecosystem functioning of a retreating Eastern Himalayan glacier

“…Previously, this bacteria has been reported from Antarctic soils, marine waters, and perialpine lakes (Paix et al 2019 , Li et al 2021 , Ortiz et al 2021 ). The predominance of the genus Pseudomonas in the supraglacial meltwater corroborates our previous culture-dependent study (Mukhia et al 2022b ). The uncultured genus Saccharimonadales LWQ8 was more enriched in the sediment samples of supraglacial and proglacial sites.…”

The microbiome of the ice-capped Cayambe Volcanic Complex in Ecuador

“…Species in this complex are capable of ice-nucleating activities (Obata et al, 1998). Within the P. fluorescens complex, there is a group named P. antarctica (Vásquez-Ponce et al, 2018), which consists of Antarctic species, but has also been reported from the East Rathong supraglacial site in Sikkim Himalaya (Mukhia et al, 2022). We found that this genus was significantly and strongly more abundant at higher altitudes (>5,200 masl) in glacier ice communities.…”

“…Pseudomonas is a genus with psychrophilic species (Margesin et al, 2009), such as those in the Pseudomonas fluorescens complex (Mukhia et al, 2022). Species in this complex are capable of ice-nucleating activities (Obata et al, 1998).…”

Isolation and Characterization of a Low-Temperature, Cellulose-Degrading Microbial Consortium from Northeastern China

“…Previous studies showed that Pseudomonas was a dominant genus in low-temperature cellulose degradation, and a key component in many other communities of soil cellulose-degrading microorganisms [ 51 , 52 ]. Furthermore, this genus is known for its cold-adaptation capabilities and can be a source of many cold-adapted enzymes for bioprospecting [ 53 ]. Moreover, P. fluorescens , a recognized cold-adapted bacterium, can cause food spoiling in a variety of frozen items while often being unchecked in soil or water [ 54 ].…”