Differential Expression of Immune Genes between Two Closely Related Beetle Species with Different Immunocompetence following Attack by Asecodes parviclava

Abstract

Endoparasitoid wasps are important natural enemies of many insect species and are major selective forces on the host immune system. Despite increased interest in insect antiparasitoid immunity, there is sparse information on the evolutionary dynamics of biological pathways and gene regulation involved in host immune defense outside Drosophila species. We de novo assembled transcriptomes from two beetle species and used time-course differential expression analysis to investigate gene expression differences in closely related species Galerucella pusilla and G. calmariensis that are, respectively, resistant and susceptible against parasitoid infection by Asecodes parviclava parasitoids. Approximately 271 million and 224 million paired-ended reads were assembled and filtered to form 52,563 and 59,781 transcripts for G. pusilla and G. calmariensis, respectively. In the whole-transcriptome level, an enrichment of functional categories related to energy production, biosynthetic process, and metabolic process was exhibited in both species. The main difference between species appears to be immune response and wound healing process mounted by G. pusilla larvae. Using reciprocal BLAST against the Drosophila melanogaster proteome, 120 and 121 immune-related genes were identified in G. pusilla and G. calmariensis, respectively. More immune genes were differentially expressed in G. pusilla than in G. calmariensis, in particular genes involved in signaling, hematopoiesis, and melanization. In contrast, only one gene was differentially expressed in G. calmariensis. Our study characterizes important genes and pathways involved in different immune functions after parasitoid infection and supports the role of signaling and hematopoiesis genes as key players in host immunity in Galerucella against parasitoid wasps.

Genome assemblies of three closely related leaf beetle species (Galerucellaspp)

“…"Inferred from homology [3]", 161,853 proteins). In addition to protein resources, transcriptome data containing 57,255 transcripts from G. pusilla were used as evidence for all three genomes (Yang et al 2020). Next, we used the candidate genes from the initial annotation to train three different ab-initio gene predictors: GeneMark v4.48 (Besemer et al 2001), Augustus v3.3.3 (Stanke et al 2006) and Snap v2013_11_29 (Korf 2004) .…”

“…The demography, host searching behavior and immunology have previously been addressed in several Galerucella species (Zheng et al 2008;Fors et al 2015;Yang et al 2020), but no genome assemblies of Galerucella species are currently available. The closest related species that has an available genome assembly is ragweed leaf beetle (Ophraella communa), which also belongs to the leaf beetle (Chrysomelidae) family (Figure 1) (Bouchemousse et al 2020).…”

Molecular assessment and transcriptome profiling of wild fish populations of Oryzias mekongensis and O. songkhramensis (Adrianichthyidae: Beloniformes) from Thailand

“…The analysis of DEGs can be performed through transcriptomic profiles to understand alterations in genes or genes in different species [49][50][51]. For DEG screening, the transcriptomic analyses showed that some gene expression levels were different between O. mekongensis and O. songkhramensis.…”

Genome assemblies of three closely related leaf beetle species (Galerucella spp.)

“…In addition to its application in biological control, Galerucella spp. has been widely investigated in both ecological ( Pappers et al 2002 ; Tanaka and Nakasuji 2002 ; Hori et al 2006 ; Fors et al 2016 ) and evolutionary ( Ikonen et al 2003 ; Stenberg and Axelsson 2008 ; Yang et al 2020 ) studies. In particular, Galerucella spp.…”

“…The demography, host searching behavior, and immunology have previously been addressed in several Galerucella species ( Zheng et al 2008 ; Fors et al 2015 ; Yang et al 2020 ), but no genome assemblies of Galerucella species are currently available. The closest related species that has an available genome assembly is ragweed leaf beetle ( Ophraella communa ), which also belongs to the leaf beetle (Chrysomelidae) family ( Bouchemousse et al 2020 ).…”