Abstract: 【Aim】 This study aims to study the roles of heat shock protein in the adaptation to temperature stress in Phenacoccus solenopsis. 【Methods】 Based on the successful transcriptome sequencing in P. solenopsis, we analyzed two sequences of heat shock protein 70 gene family ［PsHsp70 (GenBank accession no. KJ909505) and Pshsp70-4 (GenBank accession no. KJ909506)］ and one sequence of heat shock protein 90 gene family ［Pshsp90 (GenBank accession no. KJ909507)］, and used comparative quantitative real-time PCR (RT-qPCR) to analyze the expression of genes Pshsp70, Pshsp70-4 and Pshsp90 at different developmental stages (2nd instar nymph, 3rd instar nymph and female adult) of P. solenopsis in response to different temperatures (constant temperature 18 and 32℃, and temporary heat shock for 1 h at 37, 39, 41, 43 and 45℃ and then recovery for 1 h at 26℃) were detected. 【Results】 Sequence analysis showed that the Pshsp70 cDNA contains a 1 923 bp open reading frame, encoding a polypeptide of 641 amino acids with an estimated molecular mass of 70.9 kDa and an estimated isoelectric piont (pI) of 5.65. The Pshsp70-4 cDNA contains a 1 962 bp open reading frame, encoding a polypeptide of 654 amino acids with an estimated molecular mass of 71.8 kDa and an estimated isoelectric piont (pI) of 5.38. The Pshsp90 cDNA contains a 2 172 bp open reading frame, encoding a polypeptide of 724 amino acids with an estimated molecular mass of 83.5 kDa and an estimated isoelectric piont (pI) of 4.93. Both Pshsp70 and Pshsp70-4 contain the highly conserved functional motifs of the Hsp70 gene family. PsHsp70 shares 85% amino acid sequence identities with the Hsp70 proteins from Bemisia tabaci and Bombyx mori, while PsHsp70-4 shares 95% amino acid sequence identities with the Hsp70 proteins from Ericerus pela and Riptortus pedestris. Pshsp90 contains the highly conserved functional motifs of the Hsp90 gene family, and PsHsp90 shares 87% amino acid sequence identities with the Hsp90 proteins from Tribolium castaneum and Orius sauteri. The expression analysis result showed that the mRNA expression levels of the three Hsp genes in the 2nd instar nymphs were down-regulated at constant temperature 18℃, as compared with those at 26℃(the control), while at 32℃, the mRNA expression level of Pshsp70 was significantly higher than the control group in these three developmental stages. Under heat shock at 37-45℃ for 1 h and then recovery for 1 h, the relative expression levels of the three Hsp genes increased with the increase of temperature in the three different developmental stages. The correlation analysis suggested that the correlation coefficients between the expression level of the three Hsp genes in all developmental stages and the heat stress temperature were greater than 0.6, except that of Pshsp70-4 in female adult (0.225). The expression levels of the three Hsp genes in all tested stages under heat shock at 43℃ and 45℃ for 1 h and then recovery for 1 h were significantly higher than the control group. 【Conclusion】 The expression of heat shock protein genes in P. solenopsis is positively correlated with temperature, and PsHsps may play an important role in high temperature tolerance in P. solenopsis.

Key words: Phenacoccus solenopsis, heat shock protein (Hsp), temperature stress, sequence analysis, mRNA expression level, quantitative real-time PCR