Comparative transcriptome analysis reveals molecular strategies of ghost moth Thitarodes armoricanus in response to hypoxia and anoxia.

Hypoxia or anoxia greatly impact the survival of many animal species. The ghost moth Thitarodes armoricanus is distributed in the Tibetan Plateau at an average elevation of approximate 4 km above sea level and has probably evolved a superior capacity to tolerate low oxygen levels. In this study, transcriptome analysis using high-throughput RNA-seq revealed common and different adaptation strategies of T. armoricanus in response to hypoxia (11% O2 ) or anoxia. T. armoricanus adopted three common strategies for adaptation to hypoxia or anoxia: Up-regulated signal transduction pathways essential for cellular survival, strengthened cell and organelle structure and activity, and activated immune system. Under hypoxia, T. armoricanus might develop a strategy to adapt to hypoxia by suppressing TCA, oxidative phosphorylation pathways, and hypoxanthine catabolism. T. armoricanus larvae kept active under hypoxia but became coma under anoxia, probably relating to up-regulated or suppressed dopamine synthesis pathway. Furthermore, the HIF system seemed not to be essential for regulating the hypoxic and anoxic responses of this insect in Tibetan Plateau. This study provides a global view of gene expression profiles and suggests common and different adaptation strategies of T. armoricanus under hypoxic and anoxic conditions. The results are helpful for understanding the mechanism responsible for the low oxygen level tolerance of this insect species.