关键词: 棉蚜, 热激蛋白90, 棉酚, 氟吡呋喃酮, HSF

Abstract: 【Aim】The aim of this study is to identify heat shock protein (Hsp) gene in Aphis gossypii(AgHsp90) and clarify the response of AgHsp90 to temperature, plant allelochemicals and insecticide stresses. 【Methods】RT-PCR and RACE were used to clone AgHsp90 of A. gossypii, and bioinformatics analysis was conducted. The expression levels of AgHsp90 in different developmental stages (1st-4th instar nymphs and adult) and in adults at 1 h after treatments with -5, 0, 5, 10, 15, 20, 30, 35, 38 and 42 ℃, and at 24 h after treatment with plant allelochemicals (20 mg/L tannic acid, 50 mg/L gossypol, 50 mg/L 2-tridecanone and 50 mg/L quercetin) and pesticide flupyradifurone stress［LC₂₅(2.410 mg/L)］ were quantified by qRT-PCR. RNAi of AgHsp90 and heat shock factor (HSF) gene AgHSF of A. gossypii adult was performed for 24 h through feeding method to determine the mortality rate of A. gossypii adults at 24 and 48 h after treatments with 50 mg/L gossypol and LC₄₀ (4.649 mg/L) flupyradifurone through feeding and leaf dipping methods, respectively, explore the effect of AgHsp90 on the susceptibility of A. gossypii to gossypol and flupyradifurone and preliminarily verify the mutual regulation between AgHsp90 and AgHSF. 【Results】One Hsp90 gene of A. gossypii designated AgHsp90 (GenBank accession no.: UOF38310) was obtained with a 2 181 bp ORF in length. The expression levels of AgHsp90 were relatively stable in different developmental stages, with the significant difference happened between the 3rd instar nymph and adult. Temperature stress experiment result revealed that AgHsp90 was obviously high temperature inducible, but low temperature downregulated the expression level of AgHsp90. The expression level of AgHsp90 in A. gossypii adult was not significantly induced by three plant allelochemicals (gossypol, tannic acid, and quercetin) and significantly induced by 2-tridecanone and LC₂₅ flupyradifurone compared with the controls 0.5 mol/L sucrose and Triton X-100, respectively. RNAi of AgHsp90 could remarkably increase the mortality rate of A. gossypii adult resulted from gossypol and flupyradifurone compared with the control fed with dsGFP. AgHsp90 and its transcription factor AgHSF could mutually affect the expression levels using RNAi method. 【Conclusion】 The heat shock protein gene AgHsp90 of A. gossypii is high temperature and flupyradifurone inducible. AgHsp90 is mostly associated with the gossypol and flupyradifurone susceptibility of A. gossypii. The above results indicate that AgHsp90 may play crucial roles in response to high temperature and pesticide flupyradifurone stresses.

Key words: Aphis gossypii, heat shock protein 90, gossypol, flupyradifurone, HSF