Trehalose: A Crucial Molecule in the Physiology of Fungi

Abstract

Trehalose is a nonreducing disaccharide with exceptional physical and chemical properties that explain its careful preservation throughout evolution and its wide presence in the biosphere, comprising both prokaryotic and eukaryotic organisms. Indeed, bacteria contain an elaborate system for trehalose biosynthesis, which includes three different and well-characterized pathways (OtsAB, TreS and TreYZ) that provide them with ample physiological roles; for example, as carbon source, structural component or compatible solute. In contrast, in eukaryotes only the OtsAB orthologous pathway has been conserved (termed the TPS/TPP route). Surprisingly, however, trehalose synthesis does not occur in vertebrates, although they possess hydrolytic mechanisms. The trehalose metabolism has been carefully elucidated in fungi, where the sugar plays crucial physiological roles as reserve carbohydrate, stress protector or virulence factor. Recent research has also provided new evidence on whether trehalose serves as antifungal target, metabolic regulator or signaling molecule, paving new ways for biotechnological and clinical applications. All these topics are covered in this article.