Walter Abigail J, Hall David G, Duan Yong Ping
Subtropical Insects Research Unit.
Subtropical Plant Pathology Research Unit, United States Department of Agriculture-Agricultural Research Service, U.S. Horticultural Research Laboratory, Fort Pierce, FL 34945.
Plant Dis. 2012 Jun;96(6):827-832. doi: 10.1094/PDIS-08-11-0668.
Huanglongbing (HLB) is one of the most devastating diseases of citrus worldwide. 'Candidatus Liberibacter asiaticus' is the prevalent species of three HLB-associated Liberibacter spp., which is vectored by the psyllid Diaphorina citri. The vector and the bacteria have host plants outside the genus Citrus, and these plants have the potential to affect disease epidemiology within citrus groves. Murraya paniculata could be especially problematic because it is a popular ornamental plant and a host of both psyllid and bacteria. We conducted a year-long survey of eight urban plantings of M. paniculata in east-central Florida to characterize 'Ca. L. asiaticus' infection rates in plants and associated psyllids. Using sensitive quantitative polymerase chain reaction (qPCR) primers targeting two prophage genes of 'Ca. L. asiaticus', we found infection to be extremely low: less than 1% of psyllids and 1.8% of plants. With qPCR primers targeting 'Ca. L. asiaticus' 16S rDNA, none of the plants and only one psyllid were 'Ca. L. asiaticus'-positive. Therefore, the titer of 'Ca. L. asiaticus' is low in M. paniculata and associated psyllids. These results suggest that urban plantings of M. paniculata may serve as a minor source of 'Ca. L. asiaticus' inoculum.
黄龙病（HLB）是全球最具毁灭性的柑橘病害之一。“亚洲韧皮杆菌”（Candidatus Liberibacter asiaticus）是三种与黄龙病相关的韧皮杆菌属物种中最普遍的一种，由柑橘木虱传播。这种传播媒介和细菌在柑橘属以外有寄主植物，而这些植物有可能影响柑橘园内的疾病流行情况。九里香可能尤其成问题，因为它是一种受欢迎的观赏植物，同时也是木虱和细菌的寄主。我们对佛罗里达州中东部的8个城市九里香种植区进行了为期一年的调查，以确定植物和相关木虱中“亚洲韧皮杆菌”的感染率。使用针对“亚洲韧皮杆菌”两个前噬菌体基因的灵敏定量聚合酶链反应（qPCR）引物，我们发现感染率极低：木虱感染率不到1%，植物感染率为1.8%。使用针对“亚洲韧皮杆菌”16S rDNA的qPCR引物，没有植物检测呈阳性，只有一只木虱检测呈阳性。因此，九里香及其相关木虱中“亚洲韧皮杆菌”的滴度较低。这些结果表明，城市种植的九里香可能是“亚洲韧皮杆菌”接种源的次要来源。
