On the evolution and biogeography of Apple stem grooving capillovirus.

Apple stem grooving Capillovirus (ASGV) has a wide host range, notably apples, pears and citrus. It is found worldwide. In this study, the published nucleotide sequences of the genomes of 60 isolates and of over 200 coat protein (CP) genes, including those of seven newly determined Iranian isolates, were analyzed. The non-recombinant genomes showed that sequences concatenated from the replicase genes (minus a short variable region), together with the movement and CP genes gave the best supported ML phylogenies, and these also correlated best with CP phylogenies, so that information from phylogenies of the genomic sequences could be augmented, with caution, by that from CP phylogenies. The basal ASGV population was only isolated from CP samples from Himachal Pradesh of northern India. Its progeny lineages diverged into populations in south and east Asia, especially China. The ASVG population in the USA probably came from a Chinese lineage, and the Eurasian one, including seven Iranian isolates, from Indian lineages. The analyses suggests that trade, negative selection and founder effects were the most important factors affecting the genetic evolution of ASGV.