Hog1 Mitogen-Activated Protein Kinase Plays Conserved and Distinct Roles in the Osmotolerant Yeast Torulaspora delbrueckii

Abstract

Torulaspora delbrueckii has emerged during evolution as one of the most osmotolerant yeasts. However, the molecular mechanisms underlying this unusual stress resistance are poorly understood. In this study, we have characterized the functional role of the high-osmolarity glycerol (HOG) mitogen-activated protein kinase pathway in mediating the osmotic stress response, among others, in T. delbrueckii. We show that the T. delbrueckii Hog1p homologue TdHog1p is phosphorylated after cell transfer to NaCl-or sorbitol-containing medium. However, TdHog1p plays a minor role in tolerance to conditions of moderate osmotic stress, a trait related mainly with the osmotic balance. In consonance with this, the absence of TdHog1p produced only a weak defect in the timing of the osmostress-induced glycerol and GPD1 mRNA overaccumulation. Tdhog1⌬ mutants also failed to display aberrant morphology changes in response to osmotic stress. Furthermore, our data indicate that the T. delbrueckii HOG pathway has evolved to respond to specific environmental conditions and to play a pivotal role in the stress cross-protection mechanism.

Role of the HaHOG1 MAP Kinase in Response of the Conifer Root and But Rot Pathogen (Heterobasidion annosum) to Osmotic and Oxidative Stress

“…In the presence of the monovalent salts (NaCl and KCl), we observed the most strong and rapid HaHog1p activation within the first 60 min. A similar activation and kinetic pattern was also detected in other fungal species exposed to NaCl for the same period of time (0 to 60 min) [8] [43]. In this study, we showed that KCl, a less toxic salt compared to NaCl, can also activate the HaHOG1 pathway by phosphorylation of the HaHog1p MAPK.…”

Strain-dependent tolerance to acetic acid in Dekkera bruxellensis

“…Hog1p and phospho-Hog1p were analyzed as reported(Hernandez-Lopez et al 2006) with rabbit polyclonal anti-Hog1 (y-215) (sc-9079) raised against amino acids 221-435 of Hog1p of S. cerevisiae (Santa Cruz Biotechnology, Dallas, TX) and anti-phospho-p38 MAPK (Thr180/Tyr182) respectively, diluted 1:1000 in TBS-BSA 0.5 % (w/v) and Tween 20 0.3 % (v/v). Actin was used to check the amount of protein loaded and it was detected with monoclonal anti-actin antibody (cat.…”

The Emerging Role of the Yeast Torulaspora delbrueckii in Bread and Wine Production: Using Genetic Manipulation to Study Molecular Basis of Physiological Responses

“…In these fermentations, volatile acidity production remained constant throughout the entire process, in contrast with fermentation carried out by S. cerevisiae, where over 35% of the total production occurs in the initial stage of fermentation. The mechanisms of osmotic resistance in T. delbrueckii have been investigated, but are still not completely understood and are significantly different from those of S. cerevisiae (34). Survival of wine strains during the fermentation process is also imperative for their application.…”