Association of Elm Yellows Subgroup 16SrV-B Phytoplasma with a Disease of Hovenia dulcis

Abstract

Japanese raisin (Hovenia dulcis) trees with typical phytoplasma-like symptoms were observed for the first time in South Korea. The disease, named Japanese raisin witches’ broom, is progressively destructive. The cause of the graft-transmissible disease was confirmed by electron microscopy and molecular studies. The 16S rDNA sequence analysis showed that the phytoplasma was closely related to the elm yellows (EY) group, ribosomal subgroup 16SrV-B. The 16S-23S rDNA intergenic spacer region, fragment of rp operon and secY gene sequences had 96–99% similarity with members of EY phytoplasma. Based on the sequence analyses and phylogenetic studies, it was confirmed that the phytoplasma infecting Japanese raisin trees in Korea belongs to the EY group.