The adaptive landscape of wildtype and glycosylation-deficient populations of the industrial yeast Pichia pastoris

BMC Genomics

Research Article

Martin Dragosits¹  Iain B. H. Wilson¹  Josef W. Moser² 

[1] Department of Chemistry, University of Natural Resources and Life Sciences, Muthgasse 18, 1190, Vienna, Austria;Department of Chemistry, University of Natural Resources and Life Sciences, Muthgasse 18, 1190, Vienna, Austria;Austrian Centre of Industrial Biotechnology (ACIB), Muthgasse 11, 1190, Vienna, Austria;

关键词: Pichia Pastoris;    Experimental evolution;    Glucose;    Salt stress;    OCH1;   

DOI  :  10.1186/s12864-017-3952-7

 received in 2017-03-23, accepted in 2017-07-23,  发布年份 2017

来源: Springer

【 摘 要 】

BackgroundThe effects of long-term environmental adaptation and the implications of major cellular malfunctions are still poorly understood for non-model but biotechnologically relevant species. In this study we performed a large-scale laboratory evolution experiment with 48 populations of the yeast Pichia pastoris in order to establish a general adaptive landscape upon long-term selection in several glucose-based growth environments. As a model for a cellular malfunction the implications of OCH1 mannosyltransferase knockout-mediated glycosylation-deficiency were analyzed.ResultsIn-depth growth profiling of evolved populations revealed several instances of genotype-dependent growth trade-off/cross-benefit correlations in non-evolutionary growth conditions. On the genome level a high degree of mutational convergence was observed among independent populations. Environment-dependent mutational hotspots were related to osmotic stress-, Rim - and cAMP signaling pathways. In agreement with the observed growth phenotypes, our data also suggest diverging compensatory mutations in glycosylation-deficient populations. High osmolarity glycerol (HOG) pathway loss-of-functions mutations, including genes such as SSK2 and SSK4, represented a major adaptive strategy during environmental adaptation. However, genotype-specific HOG-related mutations were predominantly observed in opposing environmental conditions. Surprisingly, such mutations emerged during salt stress adaptation in OCH1 knockout populations and led to growth trade-offs in non-adaptive conditions that were distinct from wildtype HOG-mutants. Further environment-dependent mutations were identified for a hitherto uncharacterized species-specific Gal4-like transcriptional regulator involved in environmental sensing.ConclusionWe show that metabolic constraints such as glycosylation-deficiency can contribute to evolution on the molecular level, even in non-diverging growth environments. Our dataset suggests universal adaptive mechanisms involving cellular stress response and cAMP/PKA signaling but also the existence of highly species-specific strategies involving unique transcriptional regulators, improving our biological understanding of distinct Ascomycetes species.

【 授权许可】

CC BY   
© The Author(s). 2017