First Report of Die-Back on Rose (Rosa hybrida) Caused by Lasiodiplodia pseudotheobromae in Korea

Abstract

In 2015, symptoms of die-back on Rosa hybrida were observed in Taean, Korea. The aims of this study were to determine the cause of die-back on Rosa hybrida and characterize the pathogen. The fungal isolates were obtained and used for pathogenicity test, morphological and molecular analyses. The pathogenicity test on healthy branches of Rosa hybrida produced die-back, as the original symptoms. For the morphological study, the isolates were inoculated onto potato dextrose agar and incubated for 7 days at 25°C. The colonies grew up quickly and turned white to gray in color. Conidia were observed under an optical microscope. The features of conidia were ellipsoidal, grayish brown in color, 20-31×11-17 µm in size and had one septum. Molecular analyses of the ITS region, TEF and TUB genes were conducted to confirm the identity of the pathogen. The phylogenetic tree of the multi-gene sequences indicated that the causal agent was Lasiodiplodia pseudotheobromae. This study is the first report of die-back caused by Lasiodiplodia pseudotheobromae on Rose (Rosa hybrida).

Keywords

• Botryosphaeriaceae
• Lasiodiplodia pseudotheobromae
• Rose die-back
• Rosa hybrida
• Rose pathogen