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Chiaki Y.,Kagoshima University | Fukumoto T.,Kagoshima University | Fukumoto T.,Kagoshima Prefecture Institute for Agricultural Development | Nakamura M.,Kagoshima University | Iwai H.,Kagoshima University
European Journal of Plant Pathology | Year: 2015

East Asian Passiflora virus (EAPV) is a member of the genus Potyvirus in the family Potyviridae. In this study, we collected 15 isolates of EAPV from two different areas (the Yuwan area of Uken village and the Sumiyo town of Amami city) on Amami Oshima Island, Japan. The sequences of polyproteins from 10 isolates and the NIb and CP regions of five isolates were determined. The nucleotide and amino acid sequence identities of polyproteins within each population were very high, and those between isolates from both areas were also high. However, five characteristic nonsynonymous substitutions were uniformly observed in the P3 and CP regions of Sumiyo isolates. Recombination analysis revealed that there was no evidence of recombination in any of the isolates from Amami Oshima Island. The selection pressure analysis showed that as a whole, the EAPVs of both populations underwent negative selection but the extent of the negative selection varied. These results were supported by a neutrality test. The gene differentiation and gene flow analysis suggested that the Sumiyo and Yuwan populations were differentiated clearly and gene flow occurred only infrequently. These results were supported by phylogenetic analysis. It was concluded that the two populations evolved independently in each respective area. © 2015 Koninklijke Nederlandse Planteziektenkundige Vereniging Source

Chiaki Y.,Kagoshima University | Nasir N.,Andalas University | Herwina H.,Andalas University | Sonoda A.,Kagoshima University | And 4 more authors.
European Journal of Plant Pathology | Year: 2015

Banana bunchy top disease is caused by the Banana bunchy top virus (BBTV), which is a species of the genus Babuvirus in the family Nanoviridae. In this study, we collected 61 isolates of BBTV from Sumatra Island. The sequences of DNA-R and DNA-S of 61 samples and DNA-U3 of 37 samples were determined. Although the Sumatra population has different sequences in the stem-loop region in DNA-U3, it is generally very similar, with little or no variation according to planting area or the varieties and genome types of the host. The comparison of sequences between Sumatra isolates and those from other areas showed that the sequence identity with the Asian group is higher than with the South Pacific group. The genetic analysis showed that the Sumatra population has very low diversity compared with other areas. Recombination analysis revealed that there was no evidence of recombination in the Sumatra population. The selection pressure analysis indicated that all Sumatra populations received negative selection. The selection pressure among the viruses infecting the banana varieties having the genotypes of AAB or ABB received a slightly weaker negative selection than that of the viruses infecting the varieties with AA or AAA genotypes. A neutrality test suggested the sudden expansion of the West Sumatra population. This is the first report to survey the BBTV on Sumatra Island. © 2015, Koninklijke Nederlandse Planteziektenkundige Vereniging. Source

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