Analysis of smHsp genes in Lymantria dispar and its response to carbaryl stress

Small heat shock proteins of insect with molecular weight from 12 to 43 kDa are stress proteins with molecular chaperone activity and can assist protein folding and transporting under environmental stress. In present study, the full length of six smHsp cDNA was identified from Lymantria dispar transcriptome. The open reading frames (ORF) of smHsps were from 444 to 567 bp encoding proteins of 147-188 amino acid residues with the theoretical pI of 5.58-6.17. These smHsps were named as LdHsp17.0, LdHsp18.7, LdHsp19.1, LdHsp20.3, LdHsp21.3 and LdHsp21.4 according to their molecular mass. The effects of sublethal concentrations (LC₅, LC₁₀ and LC₃₀) of carbaryl on smHsp gene expression in L. dispar larvae were analyzed using real-time RT-PCR technology. The results showed that the expressions of LdHsp20.3, LdHsp19.1 and LdHsp17.0 were induced while those of LdHsp21.4, LdHsp21.3 and LdHsp18.7 were inhibited under three sublethal concentrations of carbaryl. The smHsp gene expressions were in concentration- and time-dependent way. Our study provides the basis for further studying the functions of smHsp and their roles in insecticide resistance in L. dispar.