The gene expression and the activity of enzyme synthesis of trehalose during development ofAscaris suum(Nematoda) eggs

Involvement of trehalose-6-phosphate synthase in innate immunity of Musca domestica

Trehalose-6-phosphate synthase (TPS) is responsible for synthesizing trehalose, which is prevalent in crustaceans and insects as blood-sugar. In this paper, a TPS gene from Musca domestica(MdTPS)has been cloned and characterized. MdTPS promoter was analyzed, and its transcriptional activity was verified in vitro by Sf9 cell. Quantitative RT-PCR analysis revealed that the MdTPS transcription was up-regulated following bacterial challenge by Escherichia coli or Staphylococcus aureus. Meanwhile, trehalose is accumulated in larvae upon bacterial challenge. Significantly increased mortality can be observed in MdTPS depleted (RNA interference, RNAi) larvae under bacterial infection. Interestingly, feeding trehalose led to increasing trehalose content in larvae, and the effects of RNAi targeting MdTPS on host survival against bacterial challenge was partly counteracted. Taken together, these results suggest that MdTPS acts as an inducible anti-stress gene that takes part in immune defense in M. domestica via synthesizing its product trehalose.

Invertebrate Trehalose-6-Phosphate Synthase Gene: Genetic Architecture, Biochemistry, Physiological Function, and Potential Applications

The non-reducing disaccharide trehalose is widely distributed among various organisms. It plays a crucial role as an instant source of energy, being the major blood sugar in insects. In addition, it helps countering abiotic stresses. Trehalose synthesis in insects and other invertebrates is thought to occur via the trehalose-6-phosphate synthase (TPS) and trehalose-6-phosphate phosphatase (TPP) pathways. In many insects, the TPP gene has not been identified, whereas multiple TPS genes that encode proteins harboring TPS/OtsA and TPP/OtsB conserved domains have been found and cloned in the same species. The function of the TPS gene in insects and other invertebrates has not been reviewed in depth, and the available information is quite fragmented. The present review discusses the current understanding of the trehalose synthesis pathway, TPS genetic architecture, biochemistry, physiological function, and potential sensitivity to insecticides. We note the variability in the number of TPS genes in different invertebrate species, consider whether trehalose synthesis may rely only on the TPS gene, and discuss the results of in vitro TPS overexpression experiment. Tissue expression profile and developmental characteristics of the TPS gene indicate that it is important in energy production, growth and development, metamorphosis, stress recovery, chitin synthesis, insect flight, and other biological processes. We highlight the molecular and biochemical properties of insect TPS that make it a suitable target of potential pest control inhibitors. The application of trehalose synthesis inhibitors is a promising direction in insect pest control because vertebrates do not synthesize trehalose; therefore, TPS inhibitors would be relatively safe for humans and higher animals, making them ideal insecticidal agents without off-target effects.