The Qinghai-Tibet Plateau (QTP) is known for extreme natural environments and, surprisingly, has been reported to contain widespread organic pollutants. Rhodococcus can survive a variety of extreme environments and degrade many organic contaminants. Here, we isolated a Rhodococcus strain (FXJ9.536 = CGMCC 4.7853) from a soil sample collected in the QTP. Phylogenomic analysis indicated that the strain represents a novel Rhodococcus species, for which the name Rhodococcus tibetensis sp. nov. is proposed. Interestingly, R. tibetensis FXJ9.536 maintained a fast growth rate and degraded 6.2% of p-nitrophenol (4-NP) and 50.0% of malathion even at 10 °C. It could degrade 53.6% of 4-NP and 99.9% of malathion at a moderate temperature. The genome of R. tibetensis FXJ9.536 contains 4-hydroxyphenylacetate 3-monoxygenase and carboxylesterase genes, which are likely associated with the degradation of 4-NP and malathion, respectively. Further genomic analysis revealed that the strain might employ multiple strategies to adapt to the harsh QTP environment. These include synthesizing cold shock proteins, compatible solutes, secondary metabolites, and storage compounds, utilizing inorganic compounds as energy and nutrition sources, as well as degrading a range of organic pollutants. Overall, our study reveals the potential of a QTP-derived new actinobacterial species for environmental adaptation and remediation in cold regions.
Keywords: Qinghai-Tibet Plateau; Rhodococcus tibetensis FXJ9.536; adaptation strategy; degradation; malathion; p-nitrophenol (4-NP).