A Report of Pectobacterium carotovorum subsp. actinidiae Causing Kiwifruit Bacterial Canker in Guangxi, China

A bacterial pathogen strain was isolated from susceptible tissue of Hongyang variety kiwifruit in Zhongfeng Town, Ziyuan County, Guilin City, Guangxi, China. Due to the relatively single variety of kiwifruit in Guangxi, the control technology of fruit farmers is backward, and the climate is humid, which is suitable for the growth of pathogenic bacteria, resulting in frequent occurrence of diseases. In this study, the pathogen strain was identified based on morphological, physiological, and biochemical tests; 16S rRNA gene; PCR detection with specific primers; and Biolog analysis. The results showed that a tobacco allergic reaction could be induced by inoculation with the pathogenic bacteria. Additionally, brown necrotic plaques appeared on kiwifruit leaves, necrotic phloem lesions appeared, and wounds on kiwifruit branches turned brown. The characteristics identified by morphological, physiological, biochemical, and Biolog identification were similar to those caused by Pectobacterium sp. Through 16S rRNA gene sequence analysis and PCR identification with specific primers, bands with a size corresponding to target bands indicated that the pathogen was Pectobacterium carotovorum subsp. actinidiae. This is the first report of kiwifruit canker disease caused by P. carotovorum subsp. actinidiae in Guangxi, China. In addition, through this study, a preliminary understanding of the pathogen has been obtained, which will lay the foundation for the prevention and control of the disease in the future.