Acta Entomologica Sinica ›› 2016, Vol. 59 ›› Issue (11): 1182-1188.doi: 10.16380/j.kcxb.2016.11.005

• RESEARCH PAPERS • Previous Articles     Next Articles

Expression of nicotinic acetylcholine receptor gene in Plutella xylostella (Lepidoptera: Plutellidae) after long-term exposure to low concentration of spinosad

YIN Xian-Hui1, WU Qing-Jun2,*, ZHANG You-Jun2, LONG You-Hua1, WU Xiao-Mao1, LI Rong-Yu1, LI Ming1, ZHAO Zan-Wei1, WANG Ying1   

  1. (1. Institute of Crop Protection, Guizhou University, Guiyang 550025, China; 2. Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China)
  • Online:2016-11-20 Published:2016-11-20

Abstract: 【Aim】 This study aims to investigate the sublethal effects of spinosad on Plutella xylostella after long-term exposure to low concentration of spinosad. 【Methods】 The Sub strain of P. xylostella was continuously selected using the LC25 of spinosad. The susceptibility of the 4th instar larvae of various subpopulations of P. xylostella to spinosad was assayed by leaf dip feeding method, and the change of expression level of nicotinic acetylcholine receptor (nAChR) α subunit gene in the 4th instar larvae of P. xylostella treated with low concentration of spinosad was determined by quantitative real-time PCR. 【Results】 The sensitivity of P. xylostella to spinosad decreased across generations. After selection with the LC25 of spinosad for ten generations (Sub10), the Sub strain developed 2.70-fold resistance compared with the SS strain. Quantitative real-time PCR analysis indicated that the expression level of nAChR α subunit gene decreased with generations and significantly decreased by 32.04% in the Sub10 generation compared to that in the SS strain, and the expression level in the spinosad resistant strain RR (resistance ratio=17.85-fold) was only 37% of that in the SS strain. 【Conclusion】 This multi-generational study found the possible correlation between spinosad susceptibility and the expression abundance of nAChR α subunit gene in P. xylostella, and this is helpful for further understanding of spinosad resistance mechanisms in P. xylostella.  

Key words: Plutella xylostella, spinosad, insecticide resistance, nAChR, gene expression