Virus Discovery in Desert Tortoise Fecal Samples: Novel Circular Single-Stranded DNA Viruses.

Joseph P Orton,Kenro Kusumi,Arvind Varsani,Rafaela S Fontenele,Daniel J Leavitt,Greer A Dolby,Melissa A Wilson,Timothy H Webster,Kara Schmidlin,Matheo Morales,Simona Kraberger

doi:10.3390/v12020143

Abstract

The Sonoran Desert tortoise Gopherus morafkai is adapted to the desert, and plays an important ecological role in this environment. There is limited information on the viral diversity associated with tortoises (family Testudinidae), and to date no DNA virus has been identified associated with these animals. This study aimed to assess the diversity of DNA viruses associated with the Sonoran Desert tortoise by sampling their fecal matter. A viral metagenomics approach was used to identify the DNA viruses in fecal samples from wild Sonoran Desert tortoises in Arizona, USA. In total, 156 novel single-stranded DNA viruses were identified from 40 fecal samples. Those belonged to two known viral families, the Genomoviridae (n = 27) and Microviridae (n = 119). In addition, 10 genomes were recovered that belong to the unclassified group of circular-replication associated protein encoding single-stranded (CRESS) DNA virus and five circular molecules encoding viral-like proteins.

Highlights

The Sonoran Desert tortoises (Gopherus morafkai) are long-lived animals (>50 years in the wild) [1,2]adapted to the Mojave and Sonoran deserts of southwestern North America
The Sonoran Desert tortoise does not appear to face the health-related effects of upper respiratory tract disease observed in Mojave desert tortoise caused by infectious bacterium
Using a viral metagenomic approach, we identified 156 unique complete genomes of single-stranded DNA (ssDNA)

Summary

Introduction

Adapted to the Mojave and Sonoran deserts of southwestern North America. Desert tortoises eat a wide range of native desert grasses [6], are active in the summer monsoon [7], occupy rocky hillsides and streambeds laden with caliche caves [8], and usually use existing rock or caliche shelters [7]. They are thought to have speciated in isolation from Mojave desert tortoise (Gopherus agassizii) approximately 5 MYA when the Colorado River bisected the ancestral population. Differences in the timing and amount of rainfall between the Mojave and Sonoran deserts may have led to differential adaptation between these species over the same time period [9].

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