Genetic Determinism and Evolutionary Reconstruction of a Host Jump in a Plant Virus.
In spite of their widespread occurrence, only few host jumps by plant viruses have been evidenced and the molecular bases of even fewer have been determined. A combination of three independent approaches, 1) experimental evolution followed by reverse genetics analysis, 2) positive selection analysis, and 3) locus-by-locus analysis of molecular variance (AMOVA) allowed reconstructing the Potato virus Y (PVY; genus Potyvirus, family Potyviridae) jump to pepper (Capsicum annuum), probably from other solanaceous plants. Synthetic chimeras between infectious cDNA clones of two PVY isolates with contrasted levels of adaptation to C. annuum showed that the P3 and, to a lower extent, the CI cistron played important roles in infectivity toward C. annuum. The three analytical approaches pinpointed a single nonsynonymous substitution in the P3 and P3N-PIPO cistrons that evolved several times independently and conferred adaptation to C. annuum. In addition to increasing our knowledge of host jumps in plant viruses, this study illustrates also the efficiency of locus-by-locus AMOVA and combined approaches to identify adaptive mutations in the genome of RNA viruses.
Laboratory of Virology, Benaki Phytopathological Institute, Kifissia, Greece.
Nikon
N
Vassilakos
INRA, UR407 Pathologie Végétale, Montfavet, France.
Vincent
V
Simon
Laboratory of Virology, Benaki Phytopathological Institute, Kifissia, Greece.
Aliki
A
Tzima
Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej, Frederiksberg C, Denmark.
Elisabeth
E
Johansen
INRA, UR407 Pathologie Végétale, Montfavet, France benoit.moury@avignon.inra.fr.
Benoît
B
Moury
D005075:Biological Evolution; D002212:Capsicum / Q000821:virology; D003062:Codon; D019143:Evolution, Molecular; D023061:Gene Order; D033141:Genetic Determinism; D056426:Genetic Loci; D016679:Genome, Viral; D005838:Genotype; D009154:Mutation; D010802:Phylogeny; D010935:Plant Diseases / Q000821:virology; D010942:Plant Viruses / Q000145:classification / Q000235:genetics*; D014764:Viral Proteins / Q000235:genetics; D056189:Viral Tropism / Q000235:genetics*
D003062:Codon; D014764:Viral Proteins
AMOVA; Potato virus Y; Potyvirus; Solanaceae; host jump