Distinct Viral Populations Differentiate and Evolve Independently in a Single Perennial Host Plant

Abstract

The complex structure of virus populations has been the object of intensive study in bacteria, animals, and plants for over a decade. While it is clear that tremendous genetic diversity is rapidly generated during viral replication, the distribution of this diversity within a single host remains an obscure area in this field of science. Among animal viruses, only Human immunodeficiency virus and Hepatitis C virus populations have recently been thoroughly investigated at an intrahost level, where they are structured as metapopulations, demonstrating that the host cannot be considered simply as a "bag" containing a homogeneous or unstructured swarm of mutant viral genomes. In plants, a few reports suggested a possible heterogeneous distribution of virus variants at different locations within the host but provided no clues as to how this heterogeneity is structured. Here, we report the most exhaustive study of the structure and evolution of a virus population ever reported at the intrahost level through the analysis of a Prunus tree infected by Plum pox virus for over 13 years following a single inoculation event and by using analysis of molecular variance at different hierarchical levels combined with nested clade analysis. We demonstrate that, following systemic invasion of the host, the virus population differentiates into several distinct populations that are isolated in different branches, where they evolve independently through contiguous range expansion while colonizing newly formed organs. Moreover, we present and discuss evidence that the tree harbors a huge "bank" of viral clones, each isolated in one of the myriad leaves.

Estimation of the number of virus particles transmitted by an insect vector

“…The insensitivity to s was still enhanced by increasing values of . is an important parameter to take into account for plant viruses, because compartmentalization of virus variants within plants was frequently observed (15,26,27) and may be the consequence of genetic drift that occurred at the plant tissue level during plant infection.…”

Sequence diversity, population genetics and potential recombination events in grapevine rupestris stem pitting-associated virus in Pacific North-West vineyards

“…A recent study has shown that plum pox virus has evolved into several distinct populations to the point that in different parts of the same Prunus tree, the composition of these populations was different over a period of 13 years after inoculation (Jridi et al, 2006). It will be interesting to pursue similar studies with GRSPaV to better understand the dynamics of genetic Genetic diversity and putative recombination in GRSPaV diversity and the potential association between different Vitis spp.…”

No recombination detected in artificial potyvirus mixed infections and between potyvirus derived transgenes and heterologous challenging potyviruses

“…Because of the genome compatibility of PVY strains, the No recombination in artificial potyvirus infections probability of finding recombinants of PVY/PVY is expected to be higher than detecting recombinants between PPV/TVMV, PPV-SK68/PVY-H or PVA/PVY-O. However, we can not state categorically that the time frame from inoculation to RNA isolation (up to four weeks) was sufficient to generate recombinant genomes, since Jridi et al (2006) have recently shown that sequence heterogeneity in PPV occurred in a plum tree over 13 years after a single infection. In future studies, the experimental design should critically address the period from inoculation to detection of recombinant viruses.…”