Transcriptome analysis of molecular mechanism to pyrethroids resistance in Spodoptera litura

Abstract Background Spodoptera litura is a destructive agricultural pest and had evolved resistance to multiple insecticides, especially pyrethroids. At present, the resistance mechanism to pyrethroids remains unclear. Results Four field-collected populations, namely CZ, LF, NJ and JD, were identified to have high resistance to pyrethroids, and the resistant ratio ranged from 40.8 to 1764.0-fold. To explore pyrethroids resistance mechanism, the transcriptome between pyrethroid-resistant (LF and NJ) and pyrethroid-susceptible (GX) populations were compared by RNA-sequence. Results showed that multiple differential expressed genes were enriched in metabolism-related GO terms and KEGG pathways. 35 up-regulated metabolism-related genes were screened to verify by qRT-PCR. Consistent up-regulation of 13 unigenes, including 3 P450s, 4 GSTs, 1 UGTs, 4 COEs and 1ABC, were verified in the additional pyrethroids resistant populations CZ and JD. The expression level of CYP3 and GST3, which were homologous to CYP321A8 and GST1, respectively, showed good correlation with their pyrethroids resistance level among CZ, LF, NJ and JD populations. While the expression level of CYP12, CYP14, COE4 and ABC5 showed good correlation with their pyrethroids resistance level in at least three populations. UGT5 had the highest expression level among the tested UGT genes in the four pyrethroids resistant populations. Conclusion CYP3, CYP12, CYP14, GST3, COE4, UGT5 and ABC5 play important roles in pyrethroids resistance among the four field-collected populations. Our study provided a valuable resource for further study of pyrethroid resistance mechanisms in S. litura.