Identification of Core Genes of Toll-like Receptor Pathway from Lymantria dispar and Induced Expression upon Immune Stimulant

Abstract

The gypsy moth, Lymantria dispar, is a polyphagous forest pest worldwide. The baculovirus, Lymantria dispar multiple nucleopolyhedrovirus (LdMNPV) is a natural pathogen of L. dispar. The Toll-like receptors (TLR) pathway plays a crucial role in both innate and adaptive immunity in animals. However, The TLR pathway and its underlying immune mechanism against baculovirus in L. dispar have not been explored. In this study, eleven TLRs and five downstream TLR pathway components were identified and characterized from L. dispar. Structural analysis indicated that intracellular Toll/interleukin-1 receptor (TIR) domains of LdTLRs and LdMyD88 contained three conserved motifs, and the 3D structures of TIR domains of LdTLRs possessed similar patterns in components arrangement and spatial conformation. The TLR proteins of L. dispar were placed into five monophyletic groups based on the phylogenetic analysis. LdTLR1, 2, 5, 6, 7, 8 and all identified downstream TLR pathway factors were highly induced upon LdMNPV infection, indicating that the TLR pathway of L. dispar was activated and might play a role in the immune response to LdMNPV infection. Collectively, these results help elucidate the crucial role of the TLR pathway in the immune response of L. dispar against LdMNPV, and offer a foundation for further understanding of innate immunity of the pest.

Transcriptome analysis of the endangered dung beetle Copris tripartitus (Coleoptera: Scarabaeidae) and characterization of genes associated to immunity, growth, and reproduction

“…TLR proteins from the C. tripartitus transcriptome (TLR-2, TLR-6, and TLR-7) may act as membrane receptors to drive the MyD88-dependent pathway of the Toll cascade with assistance from intracellular components. Consistent with our results, core genes of the TLR pathway ( TLRs, MyD88, and kinases) have also been identified in the transcriptome of gypsy moth, Lymantria dispar [ 70 ].…”

Characterization and Functional Analysis of Toll Receptor Genes during Antibacterial Immunity in the Green Peach Aphid Myzus persicae (Sulzer)

“…Herein, five Toll receptor genes of M. persicae were cloned, which is less than the number of Toll-related genes identified in other insects, ranging from 7 in Acyrthosiphon pisum to 14 in Bombyx mori [ 35 , 36 ]. Sequence analyses indicated that three typical conserved domains of the Toll family were found in five MpToll amino acid sequences, and a similar conservation has been found in Toll sequences in B. mori and Lymantria dispar [ 37 , 38 ]. Different domains may play distinct roles, with the TIR domain being a key site of interaction with intracytoplasmic adaptor protein MyD88 to enable intracellular signaling [ 39 ], while the LRRs domain was thought to be particularly suitable for interactions between proteins [ 40 ].…”