Research Articles : Association of Aster Yellow Phytoplasma with Witches` Broom Disease of Ash (Fraxinus rhynchophylla Hence) in Korea = Research Articles : Association of Aster Yellow Phytoplasma with Witches` Broom Disease of Ash (Fraxinus rhynchophylla Hence) in Korea

다국어 초록 (Multilingual Abstract)

Typical phytoplasma whiches` broom symptoms were observed in Ash (Fraxinus rhynchop/?ylla Hence) in Korea. The symptoms of the disease were showing abnormally small leaves, shorted internodes and proliferation of shoots. Examination of fluorescent and electron microscopy of leaf midribs revealed numerous phytoplasma bodies localized in the phloem tube cells. The phytoplasmas were detected in all the symptomatic samples by the amplification with phytoplasma specific primer pair P1/P7 consistently, and the expected size was1.8 kb. However, the phytoplasma DNA was not detected in healthy seedlings. Based on sequence analysis of amplified region, this phytoplasma has close homologies with egilodiutn phyllody, mulberry dwarf, and aster yellow phytoplasmas, 99.95%, 99.79% and 99.78%, respectively, This phylogetic analysis indicates that ash witches` broom phytoplasma should he classified in the aster yellow group 16SrVI and clearly distinct from the ash yellow group l6SrVII.