Alternaria koreana sp. nov., a new pathogen isolated from leaf spot of ovate-leaf Atractylodes in South Korea.

ABSTRACT

BACKGROUND: A new species within the genus Alternaria was isolated from the leaf spot of Atractylodes ovata in the Mungyeong and Hwabuk-myeon districts of the Gyeongbuk province of Korea. The leaves showed disease symptoms such as circular or irregular leaf spots and brown to dark brown with gray spots at the center. The leaves also showed that concentric rings were surrounded with yellow halos. METHODS AND RESULTS: Phylogenetic analysis was conducted using the sequence dataset of the internal transcribed spacer region and part of the glyceraldehyde-3-phosphate dehydrogenase. The RNA polymerase II second largest subunit, endopolygalacturonase, Alternaria major allergen gene, anonymous gene region, and translation elongation factor 1-alpha genes were used as well. Results showed that present fungal isolates were distinct from other species of the sect. Alternaria. Morphologically, the present isolates also differed from other members of the sect. Alternaria in their production of solitary conidia or conidial chains (two units) and conidial body features. Similarly, it exhibited moderate pathogenicity in the host plant. CONCLUSIONS: This study described and illustrated A. koreana as a new species and the causal agent of the leaf-spot disease on A. ovata in Korea.