Cloning of catalase gene LbCAT and its expression analysis under high and low temperature stresses in Liposcelis bostrychophila (Psopotera: Liposcelididae)

To investigate the molecular mechanism of catalase (CAT) responding to extreme high and low temperature stress in Liposcelis bostrychophila.

We cloned the CAT gene from this species and designated it LbCAT. Bioinformatics methods and real-time quantitative PCR (RT-qPCR) were employed to analyze the sequence features of LbCAT and its expression profiles under acute thermal stress (42℃ and 4℃) at 0, 60, and 120 min.

The results showed that the full-length cDNA of the LbCAT gene (GenBank entry number: OQ938787) was 1 693 bp, and the open reading frame was 1 404 bp, encoding 467 amino acids. Sequence analysis revealed that LbCAT had a domain typical of the CAT family, including a proximal active site tag (26FDRERIPERVVHAKGAG42) and a proximal heme ligand tag (316RLFAYADTH324). Phylogenetic analysis showed that L. bostrychophila was closely related to Liposcelis entomophila, which also belongs to the order Psocoptera. The expression of the LbCAT gene was induced by both high and low temperature stress. At 4℃ temperature treatment, the expression of the LbCAT gene was significantly increased at 60 min and 120 min compared with the control. At 42℃ high-temperature treatment, the expression of the LbCAT gene at 60 min and 120 min was significantly higher than that of the control.

These results suggested that LbCAT may play a critical role in the molecular mechanism of L. bostrychophila responding to extreme thermal stress.