The three trehalases Nth1p, Nth2p and Ath1p participate in the mobilization of intracellular trehalose required for recovery from saline stress in Saccharomyces cerevisiae

Trehalose accumulation is a common response to several stresses in the yeast Saccharomyces cerevisiae. This metabolite protects proteins and membrane lipids from structural damage and helps cells to maintain integrity. Based on genetic studies, degradation of trehalose has been proposed as a required mechanism for growth recovery after stress, and the neutral trehalase Nth1p as the unique degradative activity involved. Here we constructed a collection of mutants for several trehalose metabolism and transport genes and analysed their growth and trehalose mobilization profiles during experiments of saline stress recovery. The behaviour of the triple ¿nth1¿nth2¿ath1 and quadruple ¿nth1¿nth2¿ath1¿agt1 mutant strains in these experiments demonstrates the participation of the three known yeast trehalases Nth1p, Nth2p and Ath1p in the mobilization of intracellular trehalose during growth recovery after saline stress, rules out the participation of the Agt1p H+-disaccharide symporter, and allows us to propose the existence of additional new mechanisms for trehalose mobilization after saline stress.This work was supported by grants AGL 2005-00508 from the ‘Ministerio de Educación y Ciencia’ (MEC), and GVACOMP2007-157 from the ‘Generalitat Valenciana’. E. G. was a fellow of the FPI programme of the Ministerio de Educación y Ciencia (Spain)Peer Reviewe