Plum pox virus strain M detected in Japan
In Japan, Plum pox virus (Potyvirus, PPV – EPPO A2 List) was first found in 2009 in several orchards of Japanese apricots (Prunus mume) in the prefectures of Tokyo, Ibaraki and Kanagawa (EPPO RS 2011/086). At that time, only PPV-D was detected. Following this initial detection, an eradication programme and a nationwide survey were initiated. In June 2016, symptoms of PPV were observed on several apricot trees (P. mume and P. armeniaca), peach trees (P. persica) and 1 P. tomentosa tree in Yokohama city. Symptomatic trees were located in a small area of Yokohama city, most of them were grown in home gardens, and some were planted along roadsides, in parks and orchards. The age of these trees ranged from 5 to 20 years old (or more). In total, 133 symptomatic leaf samples were collected and tested (serological and molecular tests). All tested samples were found to be infected by PPV and the proportions of P. mume, P. persica, P. armeniaca, and P. tomentosa were 114 (85.7%), 3 (2.2%), 15 (11.2%) and 1 (0.75%), respectively. Sequencing of total RNAs extracted from 1 infected P. mume tree, revealed the presence of PPV-M. This is the first time that this type of isolate is detected in Japan.
The situation of Plum pox virus in Japan can be described as follows: Present, only in some areas, under eradication.
Sources
Oishi M, Inoue Y, Kagatsume R, Shukuya T, Kasukabe R, Oya H, Hoshino S, Ushiku S, Fujiwara Y, Motokura Y, Maeda Y (2018) First report of Plum pox virus strain M in Japan. Plant Disease 102(4), p 829.