云南烟草丛枝症病害研究：Ⅻ病原研究：病毒问题

Studies on Tobacco Witches' BroomSymptom Diseases in Yunnan Studies on Pathogeny:the Problem about Virus

云南烟草丛枝症病害病程表现为潜伏、过敏反应、缩顶、丛枝等４个阶段，以过敏反应导致叶片严重坏死和枯死为前期特征，以腋芽丛生而表现为黄化丛枝症为后期特征，苗期感染形成僵苗症，大田期感染表现丛枝症；汁液摩擦接种１１科３２种植物发现其只侵染烟属植物，通过机械传染（嫁接、汁液）和介体传染（菟丝子、蚜虫、烟盲蝽、叶蝉）等方式传播，该病害与文献记载的烟草丛枝、丛顶和丛蔟类病害有明显区别，可能是未见记载的病害．在云南烟草丛枝症病株的老叶和带毒蚜虫中抽提到直径约２２～２４ｎｍ的球状病毒，回接烟草发病，病株检测到和云南烟草丛枝症病害相关的低分子量ＲＮＡ，说明该病毒和云南烟草丛枝症病害有密切的关系，且与ＳＢＭＶ，ＶＴＭＶ，ＴＲＳＶ，ＡｒＭＶ，ＣａｒＭＶ，ＣＭＶ，ＢＣＭＶ，ＴＮＶ等８种病毒无血清学关系，综合各项研究和文献检索结果，作者推测该病毒可能是未见记载的病毒，建议称为“烟草簇矮病毒（Ｔｏｂａｃｏｂｕｓｈｙｄｗａｒｆｖｉｒｕｓ）”．

The process when attacked of tobacco witches' broom symptom diseases in Yunnan represents into four stages: Incubation, allergic reaction, dwarf top and witches' broom. The earlier character is that allergic reaction leads to necrotic and withering leaf, the later is that the axillary buds begin to grow excessively then appears typical yellow witches' broom symptom. The infected seedling becomes rigid, while the infected transplant appears witches' broom symptom. The pathogen only infects tabacum genus, and it can be transmitted mechanically (grafting,sap) and by vectors (dodder,aphid,shieldbug,leafhopper). The symptoms of tobacco witches' broom symptom diseases in Yunnan differ distinctly from ones of tobacco witches' broom, tobacco bushy top and rosette that articles reported. Perhaps this disease is an uncovered one. A virus particles have been obtained with diameter ranged 2024 nm from the diseased tobaccos and the aphids. The healthy tobacco inoculated with it could be infected, and the tobacco witches' broom symptomassociated lowmolecularweight RNA was found in it. These facts might prove this virus associated with the pathogen nearly. There were no serological relations between the isometric particle with SBMV, VTMV, TRSV, ArMV, CarMV, CMV, BCMV and TNV. From all researching results mentioned above, the author assume it may be an uncovered virus and suggest naming it as Tobacco bushy dwarf virus.