The green peach aphid gut contains host plant microRNAs identified by comprehensive annotation of Brassica oleracea small RNA data

Max C Thompson,Stefan Wuchty,Honglin Feng,Alex C C Wilson

doi:10.1038/s41598-019-54488-1

Max C Thompson, Stefan Wuchty + Show 2 more

Open Access

https://doi.org/10.1038/s41598-019-54488-1

Copy DOI

Abstract

Like all organisms, aphids, plant sap-sucking insects that house a bacterial endosymbiont called Buchnera, are members of a species interaction network. Ecological interactions across such networks can result in phenotypic change in network members mediated by molecular signals, like microRNAs. Here, we interrogated small RNA data from the aphid, Myzus persicae, to determine the source of reads that did not map to the aphid or Buchnera genomes. Our analysis revealed that the pattern was largely explained by reads that mapped to the host plant, Brassica oleracea, and a facultative symbiont, Regiella. To start elucidating the function of plant small RNA in aphid gut, we annotated 213 unique B. oleracea miRNAs; 32/213 were present in aphid gut as mature and star miRNAs. Next, we predicted targets in the B. oleracea and M. persicae genomes for these 32 plant miRNAs. We found that plant targets were enriched for genes associated with transcription, while the distribution of targets in the aphid genome was similar to the functional distribution of all genes in the aphid genome. We discuss the potential of plant miRNAs to regulate aphid gene expression and the mechanisms involved in processing, export and uptake of plant miRNAs by aphids.

Highlights

Most insects in the order Hemiptera are herbivores that feed on plant sap[1]
We interrogated the striking difference between the proportion of total small RNA reads that mapped to the M. persicae and Buchnera genomes in M. persicae gut versus bacteriome tissues (Fig. 2)
Our analyses revealed that two members of the M. persicae species interaction network, the host plant, B. oleracea, and an aphid facultative symbiont, Regiella insecticola, were the source of a large fraction of the unmapped small RNA reads in M. persicae gut libraries (Supplementary Table S1)

Summary

Introduction

Most insects in the order Hemiptera are herbivores that feed on plant sap[1]. Typically, insects that feed on plant sap critically depend on bacteriome housed endosymbionts to supplement dietary shortfalls in essential amino acids and vitamins[2,3,4]. Preliminary data processing of the M. persicae small RNA data available in the National Center for Biotechnology Information (NCBI) data repository as BioProject PRJNA395356 identified a striking difference between gut and bacteriome tissue samples (see Fig. 1A for arrangement of tissues in aphid host) in the proportion of total reads that mapped to the M. persicae and Buchnera genomes (Fig. 2). This difference, which was not explored by Feng et al.[12], motivated the current work. We found that the distribution of targets across the M. persicae genome were dissimilar to that observed in the B. oleracea genome targets that were strongly enriched for functions associated with transcription

Objectives

Methods

Results

Conclusion