The Glaciozyma antarctica genome reveals an array of systems that provide sustained responses towards temperature variations in a persistently cold habitat

Abstract

Extremely low temperatures present various challenges to life that include ice formation and effects on metabolic capacity. Psyhcrophilic microorganisms typically have an array of mechanisms to enable survival in cold temperatures. In this study, we sequenced and analysed the genome of a psychrophilic yeast isolated in the Antarctic region, Glaciozyma antarctica. The genome annotation identified 7857 protein coding sequences. From the genome sequence analysis we were able to identify genes that encoded for proteins known to be associated with cold survival, in addition to annotating genes that are unique to G. antarctica. For genes that are known to be involved in cold adaptation such as anti-freeze proteins (AFPs), our gene expression analysis revealed that they were differentially transcribed over time and in response to different temperatures. This indicated the presence of an array of adaptation systems that can respond to a changing but persistent cold environment. We were also able to validate the activity of all the AFPs annotated where the recombinant AFPs demonstrated anti-freeze capacity. This work is an important foundation for further collective exploration into psychrophilic microbiology where among other potential, the genes unique to this species may represent a pool of novel mechanisms for cold survival.

Stress-Induced Expression is Enriched for Evolutionarily Young Genes in Diverse Budding Yeasts

“…One complication is that stress exposure often results in hundreds of significant transcriptional changes 13,14 , most of which do not correlate with single gene deletion changes in robustness 11 . These results suggest that several genes from different gene families may contribute additively to robustness and/or that stress genes may exist as duplicates, as is the case for antifreeze protein genes in artic yeasts 15 . Thus, researchers have employed systems biology to characterize the transcriptome and/or proteome-wide stress-induced changes 13,14,[16][17][18] .…”

Expression, Characterisation and Homology Modelling of a Novel Hormone-Sensitive Lipase (HSL)-Like Esterase from Glaciozyma antarctica

“…Previously, a psychrophilic yeast named G. antarctica was successfully isolated from sea ice near Casey Research Station, Antarctica. The whole-genome sequencing of this organism was done using 454 pyrosequencing and Illumina technology, with the protein information of G. antarctica being deposited in the Glaciozyma antarctica Genome Database (GanDB) (www.mgi-nibm.my/glaciozyma_ antarctica) [42]. The gene encoding for putative esterase was chosen and known as Glaciozyma antarctica hormone-sensitive lipase (GlaEst12) esterase.…”

Computational discovery and annotation of conserved small open reading frames in fungal genomes

“…In the cellular component classification -there were 184 predicted sORFs classified into mitochondria (59), nucleus (57), endoplasmic reticulum (13), integral component of membrane (33) and Ssh1 translocon complex (22). Under the molecular function classification -the predicted sORFs were assigned to functions associated to mating pheromone activity (11), DNA and RNA binding (41), ribosome (145), cytochrome (7), protein binding (31), zinc ion binding (22), hydrogen ion transmembrane transporter activity (39), metal ion binding (16), protein heterodimerization activity (1), oxidoreductase activity (1), ATP binding (1), GTP binding (1) and ligase activity (1).…”