McCollum Greg, Hilf Mark, Irey Mike, Luo Weiqi, Gottwald Tim
United States Department of Agriculture-Agricultural Research Service (USDA-ARS), Fort Pierce, FL 34945.
Southern Gardens Citrus, Clewiston, FL 33440.
Plant Dis. 2016 Jun;100(6):1080-1086. doi: 10.1094/PDIS-08-15-0940-RE. Epub 2016 Mar 7.
Huanglongbing (HLB) disease is the most serious threat to citrus production worldwide and, in the last decade, has devastated the Florida citrus industry. In the United States, HLB is associated with the phloem-limited α-proteobacterium 'Candidatus Liberibacter asiaticus' and its insect vector, the Asian citrus psyllid (ACP; Diaphorina citri). Significant effort is being put forth to develop novel citrus germplasm that has a lower propensity to succumb to HLB than do currently available varieties. Effective methods of screening citrus germplasm for susceptibility to HLB are essential. In this study, we exposed small, grafted trees of 16 citrus types to free-ranging ACP vectors and 'Ca. L. asiaticus' inoculum in the greenhouse. During 45 weeks of exposure to ACP, the cumulative incidence of 'Ca. L. asiaticus' infection was 70%. Trees of Citrus macrophylla and C. medica were most susceptible to 'Ca. L. asiaticus', with 100% infection by the end of the test period in three trials, while the complex genetic hybrids 'US 1-4-59' and 'Fallglo' consistently were least susceptible, with approximately 30% infection. Results obtained in this greenhouse experiment showed good agreement with trends observed in the orchard, supporting the validity of our approach for screening citrus germplasm for susceptibility to HLB.
黄龙病（HLB）是全球柑橘生产面临的最严重威胁，在过去十年里，它摧毁了佛罗里达州的柑橘产业。在美国，HLB与韧皮部受限的α-变形菌“亚洲韧皮杆菌”（‘Candidatus Liberibacter asiaticus’）及其昆虫传播媒介——亚洲柑橘木虱（ACP；柑橘木虱（Diaphorina citri））有关。目前正在付出巨大努力来培育新型柑橘种质，这种种质比现有品种更不容易感染HLB。有效的筛选柑橘种质对HLB易感性的方法至关重要。在本研究中，我们在温室中将16种柑橘类型的小嫁接树暴露于自由活动的ACP传播媒介和“亚洲韧皮杆菌”接种物中。在暴露于ACP的45周内，“亚洲韧皮杆菌”感染的累积发生率为70%。大叶柑橘和枸橼树对“亚洲韧皮杆菌”最易感，在三项试验中，到试验期结束时感染率达100%，而复杂遗传杂种“US 1-4-59”和“Fallglo”始终最不易感，感染率约为30%。在这个温室实验中获得的结果与在果园中观察到的趋势高度一致，支持了我们筛选柑橘种质对HLB易感性方法的有效性。
