Background: The compatible solute trehalose is a non-reducing disaccharide, which accumulates
upon heat, cold or osmotic stress. It was commonly accepted that trehalose is only present in
extremophiles or cryptobiotic organisms. However, in recent years it has been shown that
although higher plants do not accumulate trehalose at significant levels they have actively
transcribed genes encoding the corresponding biosynthetic enzymes.
Results: In this study we show that trehalose biosynthesis ability is present in eubacteria, archaea,
plants, fungi and animals. In bacteria there are five different biosynthetic routes, whereas in fungi,
plants and animals there is only one. We present phylogenetic analyses of the trehalose-6-
phosphate synthase (TPS) and trehalose-phosphatase (TPP) domains and show that there is a close
evolutionary relationship between these domains in proteins from diverse organisms. In bacteria
TPS and TPP genes are clustered, whereas in eukaryotes these domains are fused in a single
Conclusion: We have demonstrated that trehalose biosynthesis pathways are widely distributed
in nature. Interestingly, several eubacterial species have multiple pathways, while eukaryotes have
only the TPS/TPP pathway. Vertebrates lack trehalose biosynthetic capacity but can catabolise it.
TPS and TPP domains have evolved mainly in parallel and it is likely that they have experienced
several instances of gene duplication and lateral gene transfer.