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T orulopsis versatilis strains with increased salt tolerance carry mutations in the glycerol transporter gene FPS 1
Author(s) -
Wang Xiaohua,
Wang Cong,
Wang Chunling,
Cao Xiaohong,
Hou Lihua
Publication year - 2014
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/ijfs.12349
Subject(s) - gene , glycerol , mutant , strain (injury) , chemistry , transporter , intracellular , transcription (linguistics) , microbiology and biotechnology , start codon , biology , biochemistry , messenger rna , anatomy , linguistics , philosophy
Summary The salt‐tolerant T orulopsis versatilis mutant strain, T3‐5, is able to grow in YPD medium containing 22% salt, whereas the original strain, T , used for soy sauce fermentation was only able to grow in the presence of 20% or less. Biochemical analyses showed that strain T 3‐5 had a 22% higher intracellular glycerol level than T . Sequencing of the glycerol transporter gene FPS 1 revealed a change from G to A at position 198 upstream of the start codon, changes from G to A at positions 93 and 1084, respectively, within the FPS 1 gene, and insertions of T base at positions 285 and 310, respectively, downstream of the termination codon when comparing the corresponding sequences of strains T and T 3‐5. An inverse relationship between osmotic pressure and the FPS 1 transcription level was observed for both T and T 3‐5 using q PCR . Therefore, it is possible that lower transcription levels of FPS 1 are at least partly responsible for increased osmotolerance in strain T 3‐5. Overexpression of T and T 3‐5 FPS 1 in S accharomyces cerevisiae resulted in lower salt tolerance, especially in the presence of 12% salt. The data suggest that decreased expression levels of and/or alteration in the FPS 1 protein contributed to increased salt tolerance of T 3‐5.