We have studied the effect of temperature on the contribution of Hsp104 and trehalose to barotolerance using mutants deficient in Hsp104 and trehalose synthesis. When compared with a corresponding wild type strain, mutants of Hsp104 did not show temperature dependent barotolerance when the incubation temperature during the hydrostatic pressure treatment was increased. However, a mutant deficient in trehalose synthesis showed features similar to a wild type strain. Furthermore, the Hsp104 level was low in the insoluble fraction of the wild type strain after pressure treatment at 35 degrees C but not at 4 degrees C, and the protein profiles in the insoluble fraction were different between 35 degrees C and 4 degrees C. In contrast to the Hsp104 deficient mutants, the protein profile of the wild type after pressure treatment at 35 degrees C favors the role of Hsp104 as a disaggregator of proteins during hydrostatic pressure stress. These results suggest that the role of Hsp104 in barotolerance is temperature dependent in contrast to trehalose.