Copper stress response in yeast Rhodotorula mucilaginosa AN5 isolated from sea ice, Antarctic

Abstract

Heavy metal pollution in Antarctic is serious by anthropogenic emissions and atmospheric transport. To dissect the heavy metal adaptation mechanisms of sea-ice organisms, a basidiomycetous yeast strain AN5 was isolated and its cellular changes were analyzed. Morphological, physiological, and biochemical characterization indicated that this yeast strain belonged to Rhodotorula mucilaginosa AN5. Heavy metal resistance pattern of Cd > Pb = Mn > Cu > Cr > Hg was observed. Scanning electron microscopic (SEM) results exhibited altered cell surface morphology under the influence of copper metal compared to that with control. The determination of physiological and biochemical changes manifested that progressive copper treatment significantly increased antioxidative reagents content and enzymes activity in the red yeast, which quench the active oxygen species to maintain the intercellular balance of redox state and ensure the cellular fission and growth. Comparative proteomic analysis revealed that, under 2 mM copper stress, 95 protein spots were tested reproducible changes of at least 10-fold in cells. Among 95 protein spots, 43 were elevated and 52 were decreased synthesis. After MALDI TOF MS/MS analysis, 51 differentially expressed proteins were identified successfully and classified into six functional groups, including carbohydrate and energy metabolism, nucleotide and protein metabolism, protein folding, antioxidant system, signaling, and unknown function proteins. Function analysis indicated that carbohydrate and energy metabolism-, nucleotide and protein metabolism-, and protein folding-related proteins played central role to the heavy metal resistance of Antarctic yeast. Generally, the results revealed that the yeast has a great capability to cope with heavy metal stress and activate the physiological and protein mechanisms, which allow more efficient recovery after copper stress. Our studies increase understanding of the molecular resistance mechanism of polar yeast to heavy metal, which will be benefitted for the sea-ice isolates to be a potential candidate for bioremediation of metal-contaminated environments.

High-throughput sequencing of fungal communities across the perennial ice block of Scărișoara Ice Cave

“…Taxa affiliated to the Microbotryomycetes class were mainly present in the 900 years old clear ice layer, corresponding to a variety of black yeasts belonging to Mrakia sp., C. victoriae and Rhodotorula sp. (Kan and others, 2018). These phylotypes, also found in cultured fungal communities from Scărișoara Ice Cave in both 1 and 900 years old ice layers (Brad and others, 2018), have been recently identified in 10 000 years old permafrost from Swiss Alps (Frey and others, 2016).…”

Lipid and Carotenoid Production by Rhodotorula glutinis with a Combined Cultivation Mode of Nitrogen, Sulfur, and Aluminium Stress

“…All the reports that have studied the effect of metal on carotenoid production confirmed its stimulatory role on carotenoid production, explaining this by hypothesising a possible activation or inhibition mechanism of selected metal ions on specific carotenogenic enzymes, in particular, on a specific desaturase involved in carotenoid biosynthesis [14]. Elsewhere, it was noted that the determination of physiological and biochemical changes of Rhodotorula mucilaginosa AN5 after progressive copper treatment stated a significant increase in the antioxidative reagents content and enzymes activity, which quenched the active oxygen species to maintain the intercellular balance of the redox state and ensure the cellular fission and growth [55]. Another recent study implemented multi-omics metabolism analysis to investigate the mechanisms involved in irradiation-induced stress resistance in R. glutinis.…”

“…Sci. 2019, 9, x FOR PEER REVIEW 14 of 20 maintain the intercellular balance of the redox state and ensure the cellular fission and growth [55]. Another recent study implemented multi-omics metabolism analysis to investigate the mechanisms involved in irradiation-induced stress resistance in R. glutinis.…”

Cloning and functional characterization of a novel metallothionein gene in Antarctic sea‐ice yeast (Rhodotorula mucilaginosa)

“…Whereas, to the best of our knowledge, no relevant study of the MTs from the Antarctic yeast Rhodotorula mucilaginosa was published. While metal tolerance and protein response to metal stress in this yeast have been reported , MT‐mediated metal adaptation has not. In this study, the MT gene ( RmMT ) from the polar yeast R. mucilaginosa AN5 was cloned and its molecular characteristics were studied.…”