APPLIED MICROBIAL AND CELL PHYSIOLOGY Trehalose synthesis in Saccharomycopsis fibuligera does not respond to stress treatments L. K. Liang & X. K. Wang & K. L. Zhu & Z. M. Chi Received: 21 July 2006 / Revised: 14 September 2006 / Accepted: 18 September 2006 / Published online: 4 November 2006 # Springer-Verlag 2006 Abstract Synthesis of trehalose in Saccharomycopsis fibuligera sdu under various stress conditions was investi- gated. Neither the activation of trehalose-6-phosphate synthase (SfTPS1) nor the change in trehalose content was observed under stress exposure of S. fibuligera sdu cells. The results of reverse transcription polymerase chain reaction, which was performed with the specific primers designed to target the SfTPS1 gene fragment cloned from this strain, also showed that all stress treatments did not increase the expression of SfTPS1 gene. These results demonstrated that synthesis of trehalose in response to stress conditions in S. fibuligera sdu clearly differs from that of Saccharomyces cerevisiae and most other fungi. The phylogenetic analysis of the amino acid sequence deduced from the SfTPS1 gene fragment showed that the SfTPS1 sequence formed a separate family that was far related to S. cerevisiae TPS1. The yeast strain, which can accumulate a large amount of trehalose under normal growth con- ditions, has many applications and TPS1 gene in such strain may have unique use in transgenic organisms. Keywords Trehalose . TPS1 gene . Stress treatment . Saccharomycopsis fibuligera Introduction Trehalose is a nonreducing disaccharide that has been found in many organisms. In addition to its nonreducing characteristic, it possesses several unique physical proper- ties, which include high hydrophilicity and chemical stability, non-hygroscopic glass formation, and the absence of internal hydrogen bond formation. These features account for the principal role of trehalose as a stress metabolite (Aranda et al. 2004). It is now being recognized as a crucial defense mechanism that stabilizes proteins and biological membranes under a variety of stress conditions (Gancedo and Flores 2004). Based on its unique properties, it can be used as a cryoprotectant for cells in medicine and microbiology, as an effective component in cosmetics, as a stabilizer for clinical reagents and bioproducts, or even as a preserve for fresh foodstuff (Schiraldi et al. 2002). Trehalose is synthesized in a two-step process in most eukaryotes. Trehalose-6-phosphate synthase (TPS1) transfers a glycosyl unit from uridine 5′-diphosphate (UDP)-glucose to glucose-6-phosphate to yield trehalose-6-phosphate, and the latter is then split into trehalose and phosphate by trehalose-6-phosphate phosphatase (TPS2; see Hottiger et al. 1987). This pathway has been extensively studied in Escherichia coli and Saccharomyces cerevisiae. In S. cerevisiae, TPS1 forms a complex with three other subunits: TPS2, TPS3, and TSL. In E. coli, the two enzymes are separate entities. Studies in many micro- organisms have shown that numerous forms of stress induce trehalose accumulation most of the time through regulation at the level of transcription. Transcription of TPS1 gene is upregulated under a variety of stress con- ditions (Winderickx et al. 1996). The physiological hallmark of heat shock response in S. cerevisiae is a rapid, enormous increase in the concen- Appl Microbiol Biotechnol (2007) 74:1084–1091 DOI 10.1007/s00253-006-0688-8 L. K. Liang (*) Department of Biochemistry, Yantai University, Qingquan Road, No.30, Yantai 264005, China e-mail: llk1966@126.com X. K. Wang : K. L. Zhu : Z. M. Chi UNESCO Chinese Center of Marine Biotechnology, Ocean University of China, Yushan Road, No.5, Qingdao 266003, China