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A<sc>bstract</sc> Heritable microbes shape host phenotypes and are important drivers of evolution. While interactions between insects and bacterial symbionts have been extensively studied, the prevalence and consequences of insect-viral symbiosis are an open question. We show that viral symbionts in the familyIflaviridaeare widespread among aphids, an important model for research on bacterial symbiosis. We discovered multiple new species of iflaviruses that are maintained in asexual lines without apparent fitness costs and are transmitted vertically from mothers to offspring. Using field data and phylogenetic evidence, we further show that aphid iflaviruses likely move horizontally across species, but through laboratory experiments, we demonstrated that horizontal transfer among species infesting the same host plants does not persist throughout clonal lineages. Using quantitative PCR and immunohistochemistry, we discovered that viral infections localize in the host fat bodies and developing embryos. Surprisingly, we also found viral infections inside bacteria-housing cells called bacteriocytes, with a positive correlation between viral and bacterial symbiont density, indicating a mechanism for vertical transmission. Together, our work suggests that iflaviruses are an important but previously unrecognized piece of aphid symbiosis and sets the stage to use this model to answer new questions about host-microbe associations. I<sc>mportance</sc>In recent years, the rise of metatranscriptome sequencing has led to the rapid discovery of novel viral sequences in insects. However, few studies have carefully investigated the dynamics of insect-virus interactions to produce a general understanding of viral symbiosis. Aphids are a significant agricultural pest but also an important model for understanding the evolution of host-microbe interactions and the molecular basis of bacterial symbiosis. We show that heritable iflaviruses are an important but previously unrecognized part of the aphid heritable microbiome, with viral symbionts transmitted alongside bacteria from mothers to offspring, potentially via specialized bacteriocytes that house symbiotic microbes. Our findings have important implications for furthering the understanding of insect-microbe symbiosis and the potential for biocontrol of agriculturally relevant pest species.
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Draft genome sequence of the glasshouse-potato aphid Aulacorthum solani
Abstract Aulacorthum solani is a worldwide agricultural pest aphid capable of feeding on a wide range of host plants. This insect is a vector of plant viruses and causes injury to crops including stunted growth from the loss of phloem. We found that the publicly available genome for A. solani is contaminated with another aphid species, and we produced a new genome using a barcoded isogenic laboratory line. We generated Oxford Nanopore and Illumina reads to assemble a draft genome, and we sequenced RNA to aid in the annotation of our assembly. Our A. solani genome is 671 Mb containing 7,020 contigs with an N50 length of 196 kb with a BUSCO completeness of 98.6%. Out of the 24,981 genes predicted by EGAPx, 22,804 were annotated with putative functions based on homology to other aphid species. This genome will provide a useful resource for the community of researchers studying aphids from agricultural and genomic perspectives.
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- PAR ID:
- 10577974
- Publisher / Repository:
- Oxford University Press
- Date Published:
- Journal Name:
- G3: Genes, Genomes, Genetics
- Volume:
- 15
- Issue:
- 3
- ISSN:
- 2160-1836
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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