Abstract
The cyanobacterium Nostoc commune is adapted to the terrestrial environment and highly desiccation-tolerant. It is shown that N.commune accumulates trehalose as compatible solute when N. commune is subjected to desiccation and salt stress. In this study, changes of trehalose content and levels of transcript of the genes for trehalose methabolizing enzymes in N. punctiforme stain M-15 responding to desiccation and biochemical properties of these enzymes were investigated. N. punctiforme accumulated 5 μ mol trehalose per g dry weight when desiccated. The genes for trehalose synthesis ( treYZ ) and trehalose hydrolysis ( treH ) constitute a gene cluster. Levels of transcripts of treY, treZ and treH increased simultaneously after 1 h of dehydration. Trehalase activity decreased in the presence of 50 mM NaCl, and was strongly inhibited by Tris buffer. These results suggest that trehalose level is regulated mainly by change of trehalase activity.
