Djavaheri M, Rahimian H
Agricultural Biotechnology Research Institute of Iran (ABRII), Seed and Plant Improvement Campus, P.O. Box 31535-1897, Karadj, Iran.
Plant Protection Department, University of Mazandaran, P.O. Box 578, Sari, Iran.
Plant Dis. 2004 Jun;88(6):683. doi: 10.1094/PDIS.2004.88.6.683A.
Symptoms, resembling those of witches'-broom disease of lime (WBDL), consisting of proliferation and growth of spindly shoots, rosetting, development of stunted, pale green, cupped leaves, and long thin thorns were observed on some bakraee (Citrus reticulata hybrid) trees, the major rootstock species in Ghazi-Ghale (Hormozgan Province) and Kahnouj (Kerman Province) in southern Iran. Vein clearing, mottling, and mild to severe yellowing of leaves was evident on some rosetted flushes. The disease occurred sporadically, and only some branches of the tree displayed the symptoms. Sour lime (Citrus aurantifolia) trees with symptoms of WBDL were also encountered in adjacent citrus groves in the area where an association of "Candidatus Phytoplasma aurantifolia" with diseased trees was previously established. Total nucleic acids were extracted from symptomatic as well as apparently healthy bakraee (1). The nucleic acids were subjected to nested polymerase chain reaction (PCR) amplification with the universal primers R16mF2/R16mR1, followed by R16F2n/R16R2 (2). The PCR program consisted of an initial denaturation at 94°C for 2 min, followed by 40 cycles of 1 min at 94°C, 2 min at 55°C, and 3 min at 72°C. After a final extension of 10 min at 72°C, the samples were electrophoresed on agarose gels, and the DNA fragments were stained with ethidium bromide and visualized under ultraviolet light. An expected 1.2-kb product was amplified in DNA preparations from broomed bakraee and WBDL-affected sour lime trees. No such amplicon was detected in similar DNA extracts of asymptomatic trees. These results demonstrated an association of a phytoplasma with witches'-broom disease of bakraee. However, its relationship with "Candidatus Phytoplasma aurantifolia" remains to be determined. References: (1) S. L. Dellaporta et al. Plant Mol. Biol. Rep.1:19, 1983. (2) I. M. Lee et al. Int. J. Syst. Bacteriol. 48:1153, 1998.
在伊朗南部加齐-加莱（霍尔木兹甘省）和卡努吉（克尔曼省）的主要砧木品种——一些巴克莱（Citrus reticulata hybrid）树上，观察到了类似酸橙扫帚病（WBDL）的症状，包括细长嫩枝的增殖和生长、丛枝、发育不良的浅绿色杯状叶片以及细长的刺。在一些丛枝嫩梢上，叶片脉明、斑驳以及轻度至重度黄化明显可见。该病呈散发性发生，仅树木的一些枝条表现出症状。在该地区相邻的柑橘园中，也发现了有酸橙扫帚病症状的酸橙（Citrus aurantifolia）树，此前已确定“韧皮部杆菌柑橘亚种（Candidatus Phytoplasma aurantifolia）”与患病树木有关联。从有症状以及看似健康的巴克莱（1）中提取了总核酸。使用通用引物R16mF2/R16mR1，随后使用R16F2n/R16R2（2）对核酸进行巢式聚合酶链反应（PCR）扩增。PCR程序包括在94°C初始变性2分钟，随后进行40个循环，每个循环包括94°C 1分钟、55°C 2分钟和72°C 3分钟。在72°C最终延伸10分钟后，将样品在琼脂糖凝胶上进行电泳，DNA片段用溴化乙锭染色并在紫外光下观察。在扫帚状巴克莱和受酸橙扫帚病影响的酸橙树的DNA制剂中扩增出了预期的1.2kb产物。在无症状树木的类似DNA提取物中未检测到此类扩增子。这些结果表明一种植原体与巴克莱的扫帚病有关联。然而，它与“韧皮部杆菌柑橘亚种（Candidatus Phytoplasma aurantifolia）”的关系仍有待确定。参考文献：（1）S. L. Dellaporta等人，《植物分子生物学报告》1:19，1983年。（2）I. M. Lee等人，《国际系统细菌学杂志》48:1153，1998年。
