1 United States Department of Agriculture, Agricultural Research Service, Prosser, WA 99350; and.
2 United States Department of Agriculture, Agricultural Research Service, Wapato, WA 98951.
Plant Dis. 2019 Mar;103(3):468-474. doi: 10.1094/PDIS-06-18-0937-RE. Epub 2019 Jan 10.
In 2017, potato tubers suspected of being infected with the bacterium 'Candidatus Liberibacter solanacearum' were received from the Animal and Plant Health Inspection Service in the United States. A total of 368 chipping tubers were observed for internal symptoms of zebra chip disease, which is associated with 'Ca. L. solanacearum' infection in the United States, Mexico, Central America, and New Zealand. A single tuber sliced at the stem end showed classic zebra chip symptoms of darkened medullary rays, with streaking and necrotic flecking. The symptomatic tuber was confirmed positive for the bacterium by polymerase chain reaction targeting three different 'Ca. L. solanacearum' genes. Sequence analysis of these three genes, and subsequent BLAST analysis, identified the pathogen with 99, 98, and 97% identity to 'Ca. L. solanacearum' for the 16S ribosomal RNA gene, 50S ribosomal proteins L10/L12 genes, and the outer membrane protein gene, respectively. Sequence analysis did not identify the sample as one of the six known haplotypes of 'Ca. L. solanacearum,' indicating that a seventh haplotype of the pathogen was identified. This new haplotype, designated haplotype F, is now the third haplotype of the bacterium that infects Solanum tuberosum in the United States.
2017 年，从美国动植物卫生检验局收到了疑似感染细菌“甘蓝蚜黄症类菌原体”的马铃薯块茎。共观察了 368 个切片块茎，这些块茎存在与美国、墨西哥、中美洲和新西兰的“Ca. L. solanacearum”感染相关的斑马芯片病的内部症状。从茎端切开的单个块茎显示出典型的斑马芯片症状，即深色髓射线、条纹状和坏死斑。通过针对三种不同“Ca. L. solanacearum”基因的聚合酶链反应，对有症状的块茎进行了细菌检测，结果呈阳性。对这三个基因的序列分析，以及随后的 BLAST 分析，确定该病原体与“Ca. L. solanacearum”的 16S 核糖体 RNA 基因、50S 核糖体蛋白 L10/L12 基因和外膜蛋白基因的同源性分别为 99%、98%和 97%。序列分析并未将该样本鉴定为“Ca. L. solanacearum”的六个已知单倍型之一，这表明该病原体的第七个单倍型被鉴定出来。这种新的单倍型，命名为单倍型 F，现在是美国感染马铃薯的细菌的第三个单倍型。
