First Report Of Pseudomonas Amygdali Causing Bacterial Leaf Spot Of Mallotus Japonicus In South Korea

In 2014, bacterial leaf spots were observed in Mallotus japonicus on the Halla Mountain in Jeju Island, South Korea. The infected leaves showed leaf spot symptoms, that is discoloured circular or irregular leaf spots developing away from the leaf edge, rarely limited by veins. The causal pathogen was isolated from the diseased lesions and identified as Pseudomonas amygdali based on LOPAT tests and multilocus sequence analysis (MLSA) of the 16S rRNA, gyrB, rpoB and rpoD gene sequences. The pathogenicity tests conducted on potted 2-year-old M. japonicus seedlings confirmed Koch's postulates and revealed that P. amygdali was the causal agent of the leaf spots in this host. To the best of our knowledge, this is the first report of P. amygdali causing bacterial leaf spots on M. japonicus in South Korea.