Phylogeography and Coevolution of Bamboo Mosaic Virus and Its Associated Satellite RNA.

Ing-Nang Wang,Na-Sheng Lin,Wen-Bin Yeh

doi:10.3389/fmicb.2017.00886

Abstract

Bamboo mosaic virus (BaMV), a plant potexvirus, has been found only in infected bamboo species. It is frequently associated with a large, linear single-stranded satellite RNA (satBaMV) that encodes a non-structural protein. Decades of collecting across a wide geographic area in Asia have accumulated a sizable number of BaMV and satBaMV isolates. In this study, we reconstructed the BaMV phylogeny and satBaMV phylogeny with partial coat protein gene sequences and partial genomic sequences, respectively. The evolutionary relationships allowed us to infer the phylogeography of BaMV and satBaMV on the Asian continent and its outlying islands. The BaMV phylogeny suggests that the BaMV isolates from Taiwan, unsurprisingly, are most likely derived from China. Interestingly, the newly available satBaMV isolates from China were found to be most closely related to the previously established Clade III, which is found in India. The general pattern of clustering along the China/India and Taiwan divide led us to hypothesize that the Taiwan Strait has been a physical barrier to gene flow in the past evolutionary history of both BaMV and satBaMV. Lastly, cophylogeny analyses revealed a complex association pattern between BaMV and satBaMV isolates from China. In general, closely related BaMV sequences tend to carry closely related satBaMV sequences as well; but instances of mismatching with distantly related satBaMV isolates were also found. We hypothesize plausible scenarios of infection and superinfection of bamboo hosts that may be responsible for the observed association pattern. However, a more systematic sampling throughout the geographic distribution of various bamboo species is needed to unambiguously establish the origin, movement, and evolution of BaMV and satBaMV.

Highlights

Population genetic surveys and phylogenetic reconstructions of plant viruses and their associated satellites offer us invaluable insights into the observed patterns and inferred processes of plant virus evolution (García-Arenal et al, 2003) and the ecological interactions that may contribute to long-distance dispersal and emergence of new diseases (Fargette et al, 2006)
Bamboo mosaic virus (BaMV) has been detected in various parts of the world (Nelson and Borth, 2011), almost all available BaMV sequences are derived from samples obtained in Taiwan
Recent additions from China (Lin et al, 2015, 2016) provide an opportunity to explore the evolutionary history among the BaMV isolates over a larger geographic area

Summary

Introduction

Population genetic surveys and phylogenetic reconstructions of plant viruses and their associated satellites offer us invaluable insights into the observed patterns and inferred processes of plant virus evolution (García-Arenal et al, 2003) and the ecological interactions that may contribute to long-distance dispersal and emergence of new diseases (Fargette et al, 2006). Limited studies with full-length genomic sequences do reveal a clustering pattern, and suggest that isolates from Taiwan are derived from China (Lin et al, 2016, 2017b).

Results

Conclusion