title: Comparative analysis of salt-tolerant gene HOG1 in a Zygosaccharomyces rouxii mutant strain and its parent strain.
abstract: BACKGROUND
  A higher-salt-tolerant mutant strain Zygosaccharomyces rouxii 3-2 (strain S3-2) that could be used for improving the flavour of high-salt liquid state soy sauce was previously constructed from parent strain Z. rouxii (strain S) by genome shuffling. However, whether the mutations in this strain affect HOG1 encoding MAPK Hog1p and improve intracellular glycerol production remains to be elucidated.
  
  
  RESULTS
  Although two mutations in the ORF and one in the promoter of the HOG1 gene sequence of strain S3-2 occurred compared with that of strain S, there was no significant difference in secondary and tertiary structures between S3-2Hog1p and SHog1p. It was found that the expression level of S3-2HOG1 was higher than that of SHOG1 in YPDN medium with high salt concentration. Furthermore, overexpression of S3-2HOG1 in Saccharomyces cerevisiae W303-1A could improve the salt tolerance and osmotolerance of engineered yeast compared with that of SHOG1.
  
  
  CONCLUSIONS
  Enhancement of the transcription level of HOG1 induced by mutation in the promoter region may be one of the main reasons for the improved salt tolerance of strain S3-2 compared with that of strain S. Considering food security, the conservation of S3-2HOG1 would be beneficial for application of strain S3-2 in the fermentation of soy sauce.
authors.affiliation: Key Laboratory of Food Nutrition and Safety, Tianjin University of Science and Technology, Ministry of Education, Tianjin, 300457, China; School of Biological Sciences and Engineering, Shanxi University of Technology, Hanzhong, 723001, China.
authors.forename: Yonghua
authors.initials: Y
authors.lastname: Wei
authors.forename: Cong
authors.initials: C
authors.lastname: Wang
authors.forename: Meng
authors.initials: M
authors.lastname: Wang
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Cao
authors.forename: Lihua
authors.initials: L
authors.lastname: Hou
mesh_terms: D000429:Alcohol Oxidoreductases; D000595:Amino Acid Sequence; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D015966:Gene Expression Regulation, Fungal / Q000502:physiology*; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D009997:Osmotic Pressure; D011401:Promoter Regions, Genetic; D055049:Salt Tolerance / Q000235:genetics*; D020068:Zygosaccharomyces / Q000235:genetics / Q000378:metabolism*
chemical_list: D000429:Alcohol Oxidoreductases; C021496:lactate-malate transhydrogenase; D020928:Mitogen-Activated Protein Kinases
keywords: HOG1; Zygosaccharomyces rouxii mutant strain; osmostress; salt tolerance