Genome-Wide Analysis of Gene Families of Pattern Recognition Receptors in Fig Wasps (Hymenoptera, Chalcidoidea).

Hong-Xia Hou,Da-Wei Huang,Zhao-Zhe Xin,Jin-Hua Xiao

doi:10.3390/genes12121952

Hong-Xia Hou, Da-Wei Huang + Show 2 more

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https://doi.org/10.3390/genes12121952

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Journal: Genes	Publication Date: Dec 5, 2021
Citations: 4	License type: CC BY 4.0

Affiliation: Nankai University

Abstract

Pattern recognition receptors (PRRs) play important roles in detecting pathogens and initiating the innate immune response. Different evolutionary histories of pollinators and non-pollinators may result in different immune recognition systems. A previous study had reported that there were significant differences in peptidoglycan recognition proteins (PGRPs) between pollinators and non-pollinators in gene number and lineage of specific genes. In this study, based on the genomic data of 12 fig wasp species, with seven pollinators and five non-pollinators, we investigated the evolution patterns of PRRs, such as Gram-negative bacteria-binding proteins (GNBPs), C-type lectins (CTLs), scavenger receptors class B (SCRBs), fibrinogen-related proteins (FREPs), galectins, and thioester-containing proteins (TEPs). Our results showed that pollinators had no GNBP, but non-pollinators all had two gene members, which were clustered into two different clades in the phylogenetic tree, with each clade having specific domain and motif characteristics. The analysis of CTL and SCRB gene families also showed that there were lineage-specific genes and specific expansion in non-pollinators. Our results showed that there were significant differences in immune recognition between pollinators and non-pollinators, and we concluded that they had undergone flexible adaptive evolution in different environments. Our study can provide more molecular evidence for future functional studies on the immune system of fig wasps.

Highlights

Immune recognition is the first step of an effective immune response to protect hosts from invading pathogens [1]
Gram-negative bacteria-binding proteins (GNBPs) are a family that show high affinity for β-1,3-glucan, which are numerous in fungal cell walls
There was gene duplication of SCRBs in non-pollinators, suggesting that SCRBs may play important roles in resisting pathogens. These results suggested that recognition genes in the fig wasp immune system may be diverse, and the evolutionary patterns may be different between pollinators and non-pollinators

Summary

Introduction

Immune recognition is the first step of an effective immune response to protect hosts from invading pathogens [1]. The pattern recognition receptors (PRRs) of the hosts play important roles in recognizing pathogens by sensing the pathogen-associated molecular patterns (PAMPs) of microbes, such as peptidoglycan, lipopolysaccharide, lipoteichoic acid, and β-1,3-glucans [4]. The PRRs of insects are diverse, including peptidoglycan recognition proteins (PGRPs), Gram-negative bacteria-binding proteins (GNBPs), C-type lectins (CTLs), galectins, scavenger receptors (SRs), thioestercontaining proteins (TEPs), and fibrinogen-related proteins (FREPs) etc. These PRRs have their own characteristics and functions, and accurately identify non-self entities, playing important roles in innate immunity [2]. Different microorganisms would selectively activate different immune recognition genes, indicating a flexible innate immune system to cope with various bacterial infections [5]

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