Toll protein family structure, evolution and response of the whiteleg shrimp (Litopenaeusvannamei) to exogenous iridescent virus

Abstract

Whiteleg shrimp is a widely cultured crustacean, but frequent disease outbreaks have decreased production and caused significant losses. Toll‐like receptors (TLRs) comprise a large innate immune family that is involved in the innate immune response. However, understanding of their regulatory mechanism is limited. In this study, PacBio sequencing and Illumina sequencing were applied to the gill and hepatopancreas tissues of whiteleg shrimp and an integrated transcript gene set was established. The upregulation of Toll1, Toll2 and Toll3 transcripts in the hepatopancreas tissue of whiteleg shrimp after iridescent virus infection implies that these proteins are involved in the immune response to the virus; simultaneously, the TRAF6 and relish transcripts in the Toll pathway were also upregulated, implying that the Toll pathway was activated. We predicted the three‐dimensional structure of the five Toll proteins in whiteleg shrimp and humans and constructed a phylogenetic tree of the Toll protein family. In addition, there was a large discrepancy of Toll1 between invertebrates and vertebrates, presumably because of the loss of Toll1 protein sequence during the evolution process from invertebrates to vertebrates. Our research will improve the cognition of Toll protein family in invertebrates in terms of evolution, structure and function and provide theoretical guidance for researchers in this field.

Dietary supplementation with Pediococcus pentosaceus enhances the innate immune response in and promotes growth of Litopenaeus vannamei shrimp

“…The TLR signalling pathway is well known to play an important role in the defence against WSSV in L. vannamei shrimp. Among the five upregulated Toll genes in L. vannamei shrimp, Tolls1‐3 have been shown to be activated in shrimps infected with exogenous iridescent virus, resulting in the signal transduction, and release of inflammatory cytokines (Liu et al, 2021). Toll4 has been shown to inhibit WSSV infection in shrimps (H. Li et al, 2018).…”

Identification of pine wood nematode (Bursaphelenchus xylophilus) loading response genes in Japanese pine sawyer (Monochamus alternatus) through comparative genomics and transcriptomics

“…38 Pipelines for full-length transcriptome assembly were modified based on a previous study. 39 The raw data were processed into high-quality circular consensus sequencing (CCS) reads using the CCS subprogram in IsoSeq3 (v3.8.2). 40 The Lima subprogram in IsoSeq3 produced full-length reads by removing the 5 0 and 3 0 ends of cDNA primers.…”

Decapod iridescent virus 1: An emerging viral pathogen in aquaculture

“…the Toll and Imd signalling pathway; the p53 signalling pathway; and the infection. 58 However, the function of these pathways during DIV1 infection is still unknown. In contrast, several studies have indicated that DIV1 could create favourable conditions for replication by affecting the metabolism of crustaceans.…”

“…Several studies using transcriptome analysis have shown that DIV1 infection activates many innate immune signalling pathways, including the lysosome, phagosome, mitogen‐activated protein kinase signalling pathway; the Wnt signalling pathway; the NOD‐like receptor signalling pathway; the Toll and Imd signalling pathway; the p53 signalling pathway; and the phosphatidylinositol 3‐kinase and protein kinase B signalling pathway 29,37,39,57 . Liu et al performed PacBio sequencing and Illumina sequencing on the gill and haepatopancreas tissues of white leg shrimp ( L. vannamei ) and found that the transcripts of Toll1, Toll2 and Toll3 in the haepatopancreas tissues were significantly up‐regulated after DIV1 infection 58 . However, the function of these pathways during DIV1 infection is still unknown.…”