Cloning of heat shock protein gene SfHsp90 and its expression under high and low temperature and UV-A stresses.
Aim: This study aims to explore the molecular mechanism of Spodoptera frugiperda in response to high and low temperature and UV-A stresses. Methods: The heat shock protein Hsp90 gene of S. frugiperda was cloned by RT-PCR technique, and its sequence characteristics were analyzed using bioinformatics methods. The relative expression levels of Hsp90 in different developmental stages (egg, 1st-6th instar larva, pupa and adult), different adult tissues (head with antennae and compound eyes removed, thorax, abdomen, antenna, compound eye, leg, wing, midgut, testis and ovary) and adults exposed to high temperature of 36°C, low temperature of 4°C and UV-A radiation for different time (0, 30, 60, 90, 120 and 150 min) were detected by RT-qPCR. Results: The Hsp90 gene was cloned from S. frugiperda and named SfHsp90 (GenBank accession no.: MN832694). Its open reading frame (ORF) is 2 154 bp in length, encoding 717 amino acids, with the relative molecular weight of 82.52 kD and the isoelectric point (pI) of 5.01. The C-terminal sequence contains the conserved motif EEVD, suggesting that the protein is a cytoplasmic heat shock protein. Phylogenetic analysis showed that insect Hsp90 proteins are highly conserved. Developmental expression profile showed that the expression level of SfHsp90 was the highest in the 1st instar larva, and the tissue expression profile revealed that the expression levels of SfHsp90 were significantly higher in the antenna, compound eyes and head with antennae and compound eyes removed of male and female adults than in other tissues. High and low temperature stresses induced the expression of SfHsp90 obviously. The expression level of SfHsp90 in adults exposed to high temperature of 36°C was significantly higher than that of the control group. After the adults were exposed to high temperature of 36°C, the expression level of SfHsp90 increased at first and then decreased with the increase of exposure time, and reached the maximum at 60 min after exposure in male adults, while its expression level in female adults increased gradually with the prolonging of exposure time. After the adults were exposed to low temperature of 4°C, the expression level of SfHsp90 increased firstly and then decreased in male adults with the prolonging of exposure time, and reached the maximum at 30 min after exposure, while its expression level in female adults increased gradually with the prolonging of exposure time. The expression of SfHsp90 in female and male adults was induced by UV-A stress. After the adults were exposed to UV-A radiation, the expression level of SfHsp90 increased firstly and then decreased with the increase of exposure time, and reached the highest at 90 min in male adults and at 60 min in female adults, respectively. Conclusion: The differential expression of SfHsp90 in S. frugiperda adults under high and low temperature and UV-A stresses suggests that this gene plays an important role in the molecular mechanism in S. frugiperda in response to environmental stresses.