Abstract: 【Aim】 To explore the molecular mechanism of the natural enemy insect Arma chinensis in response to high or low temperature and UV-B stresses.【Methods】 The heat shock protein genes AcHsp83a and AcHsp83b of A. chinensis were cloned by RT-PCR, and their sequence characteristics were analyzed by bioinformatics methods. RT-qPCR was used to detect the expression levels of AcHsp83a and AcHsp83b in different developmental stages (egg, 1st-5th instar nymphs, female adult and male adult), different adult tissues (head, thorax, abdomen, wing, antenna, fat body, leg, Malpighian tubules, mouthparts, midgut, ovary and testis), and female and male adults at 0 (CK), 6 and 24 h after exposure to high temperature of 38 ℃, and low temperature of 4 ℃, and at 0 (CK), 6 and 12 h after UV-B stress.【Results】 Two Hsp90 genes were cloned from A. chinensis, and namely AcHsp83a (GenBank accession no.: OP791883) and AcHsp83b (GenBank accession no.: OP791884). Their open reading frames (ORFs) were 2 172 and 2 163 bp in length, encoding 723 and 720 amino acids with the relative molecular weight of 83.12 and 82.90 kD and the isoelectric point (pI) of 4.94 and 4.97, respectively, and the C-terminal sequences both contain the conserved motif EEVD, showing that they belong to the cytoplasmic Hsps. AcHsp83a and AcHsp83b are highly conserved. The expression level of AcHsp83a was the highest in eggs, whereas that of AcHsp83b was the highest in adults. The expression level of AcHsp83a was the highest in the testis of male adults, whereas that of AcHsp83b was the highest in the midgut of female adults. When the female adults were exposed to 38 ℃, 4 ℃ or UV-B, the expression levels of AcHsp83a and AcHsp83b increased firstly and then decreased with treatment time, reaching the peak at 6 h. For the male adults, the expression level of AcHsp83a increased firstly and then decreased with treatment time, and reached the peak at 6 h after exposure to 38 ℃ or UV-B. The expression level of AcHsp83a in male adults decreased firstly and then increased with treatment time, and reached the peak at 24 h after exposure to 4 ℃. Compared with the control group, 38 ℃, 4 ℃ or UV-B exposure significantly decreased the expression levels of AcHsp83b in male adults. 【Conclusion】 The differential expression of AcHsp83a and AcHsp83b in A. chinensis suggests that the two genes play important roles in the growth and development of A. chinensis and contribute to its tolerance to extreme temperatures and UV-B stress.

Key words: Arma chinensis, Hsp90, gene cloning, expression profiling, environmental stress