Identification and Pathogenicity of Colletotrichum Species Causing Anthracnose of Korean Radish (Rhaphanus sativus) in Korea

Yeun Sug  Jeong1   Jeomsoon  Kim 2,*   Sung Kee  Hong 1   Young Kee   Lee 1   

1Crop Protection Division
2Microbial Safety Team, National Institute of Agricultural Sciences, Wanju 55365, Korea

Abstract

In August 2017, anthracnose symptoms were observed on the petioles and leaf veins of Korean radish (Rhaphanus sativus) in Hongcheon, Jeongseon, and Pyeongchang of the Gangwon province, Korea. Many grayish to dark-brown spots of 1-2 mm in diameter, appeared on the lower surface and leaf veins of the radish leaves. The spots gradually enlarged and coalesced to form dark-brown irregular lesions. Ten Colletotrichum isolates were obtained from the affected tissues of the Korean radish. Out of them, eight isolates were identified as C. higginsianum and two isolates were identified as C. truncatum based on morphological characteristics and multi-l℃us molecular phylogenetic analysis using the internal transcribed spacers and intervening 5.8S rDNA (ITS), partial beta-tubulin gene (TUB2), partial actin gene (ACT), and partial chitin synthase-1 gene (CHS1). The pathogenicity test was carried out on wounded and unwounded Korean radish (cv. Siraegimu and Osarimu), and Chinese cabbage (cv. Chuno and Smart) by in℃ulating with a spore suspension. All isolates except one C. truncatum isolate developed typical symptoms on both wounded and unwounded Korean radish. In Chinese cabbage, only the plants in℃ulated with C. higginsianum isolates developed symptoms regardless of the wound. This is the first report of anthracnose caused by C. truncatum on Korean radish in Korea.

Figures & Tables

Fig. 1. Dark brown to black irregular spots on petioles and leaflets of Korean radish anthracnose caused by species. A, symptoms on petioles and leaflets in Jeongseon; B, weak symptoms on petioles in Pyeongchang.