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.

中文翻译：

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韩国首次报道杏仁假单胞菌引起日本马蹄莲细菌性叶斑病

2014年，在韩国济州岛汉拿山上的马洛图斯（Mallotus japonicus）中观察到细菌性叶斑病。受感染的叶片表现出叶斑症状，即变色的圆形或不规则叶斑远离叶缘发展，很少受叶脉限制。根据LOPAT测试和16S rRNA、gyrB、rpoB和rpoD基因序列的多位点序列分析（MLSA），从病变病变中分离出致病病原体并鉴定为杏仁假单胞菌。对盆栽 2 年生M. japonicus幼苗进行的致病性测试证实了 Koch 的假设，并揭示了杏仁核是该宿主叶斑的病原体。据我们所知，这是韩国第一次报道杏仁核菌在日本 M. japonicus上引起细菌性叶斑病。