Genetic Structure and Variability of East Asian Passiflora virus Population in Amami‐O‐shima, Japan

Abstract

AbstractOur previous study showed that the East Asian Passiflora virus (EAPV) population emerging in Amami‐O‐shima, Kagoshima prefecture, Japan, consisted only of isolates of the AO strain by RT‐PCR screening using strain‐specific primers. To evaluate the results and gain insights into the evolutionary mechanisms of EAPV, the coat protein (CP) nucleotide (nt) sequences of 17 isolates collected from four different regions (Tatsugo, Uken, Sumiyo and Setouchi) in Amami‐O‐shima and polyprotein‐encoding sequences of 8 isolates of them were determined. The nt sequence identities of resultant CP‐ and polyprotein‐encoding sequences against the type isolate of the AO strain were >98.5 and >98.8%, respectively, confirming that all the 17 isolates are of the same genetic group. Estimates of nt diversity showed that the EAPV population in Amami‐O‐shima had low diversity through the genome and all the genes were under negative selection, but the genetic constraints were varied between different protein‐encoding regions. Phylogenetic analyses revealed that EAPV isolates showed a star‐like phyl‐ogeny based on their CP‐encoding regions, and it is suggested that the population in Sumiyo has expanded recently.