Abstract: 【Aim】 ATP-binding cassette transporter (ABC transporter), a huge superfamily of membrane transporters, plays an important role in insect growth, development and insecticide resistance. This study aims to provide theoretical basis for subsequent functional studies by cloning ABCD1 of the white-backed planthopper, Sogatella furcifera and determining its expression pattern under insecticide stress. 【Methods】 The cDNA sequence of ABCD1 of S. furcifera was cloned by RT-PCR, and subjected to bioinformatics analysis. The expression levels of ABCD1 in S. furcifera at different developmental stages (1st-5th instar nymphs and 1-4 day-old male and female adults), in different tissues (head, integument, fat body, gut, leg, wing, testis and ovary) of the 5th instar nymphs and adults, and in the 3rd instar nymphs exposed to different concentrations (LC₁₀, LC₂₅, LC₅₀ and LC₉₀) of thiamethoxam, buprofezin, and abamectin were detected by RT-qPCR. 【Results】 An ABC transporter gene of S. furcifera was obtained and named SfABCD1 (GenBank accession no.: MW701394), with an open reading frame of 2 220 bp in length. It encodes a putative protein of 739 amino acid residues with the predicted molecular weight of 82.08 kD and isoelectric point of 9.32. SfABCD1 is closely related to ABCD1 of Laodelphax striatellus and Nilaparvata lugens. RT-qPCR results showed that SfABCD1 had the highest expression level in the 5th instar nymphs and was expressed in various tissues of the 5th instar nymphs and adults with the highest expression level in the gut and head of the 5th instar nymphs. After the 3rd instar nymphs were exposed to insecticides for 48 h, the expression levels of SfABCD1 in the treatment groups of buprofezin at the concentrations of LC₁₀, LC₅₀ and LC₉₀, thiamethoxam at the concentrations of LC₁₀, LC₂₅ and LC₅₀ and abamectin at the concentrations of LC₅₀ and LC₉₀ were significantly up-regulated as compared to that in the control group treated with water. When the 3rd instar nymphs were exposed to the three insecticides at the four concentrations of LC₁₀, LC₂₅, LC₅₀ and LC₉₀ for different time, the expression difference of SfABCD1 in the nymphs between the treatment group and the control group were the largest at 48 h after treatment and subsequently decreased at 96 h after treatment, and then the expression level of this gene in nymphs at 120 h after treatment was close to that in the control group. 【Conclusion】 S. furcifera can respond to the stress of buprofezin and thiamethoxam by up-regulating the expression of SfABCD1, and the expression level of SfABCD1 decreases with the increase of the concentration of thiamethoxam. In addition, S. furcifera also responds to the poison of high concentrations of abamectin by regulating the transcription level of SfABCD1.

Key words: Sogatella furcifera, ABCD1 gene, insecticide stress, expression analysis, insecticide resistance