Sasaya Takahide, Fujii Hiroya, Ishikawa Koichi, Koganezawa Hiroki
Laboratory of Plant Virology, National AGricultural Research Center for Western Region, Kagawa, Japan.
Phytopathology. 2008 Apr;98(4):464-8. doi: 10.1094/PHYTO-98-4-0464.
Mirafiori lettuce big-vein virus (MLBVV) and Lettuce big-vein associated virus (LBVaV) are found in association with big-vein disease of lettuce. Discrimination between the two viruses is critical for elucidating the etiology of big-vein disease. Using specific antibodies to MLBVV and LBVaV for western blotting and exploiting differences between MLBVV and LBVaV in host reaction of cucumber and temperature dependence in lettuce, we separated the two viruses by transfering each virus from doubly infected lettuce plants to cucumber or lettuce plants. A virus-free fungal isolate was allowed to acquire the two viruses individually or together. To confirm the separation, zoospores from MLBVV-, LBVaV-, and dually infected lettuce plants were used for serial inoculations of lettuce seedlings 12 successive times. Lettuce seedlings were infected at each transfer either with MLBVV alone, LBVaV alone, or both viruses together, depending on the virus carried by the vector. Lettuce seedlings infected with MLBVV alone developed the big-vein symptoms, while those infected with LBVaV alone developed no symptoms. In field surveys, MLBVV was consistently detected in lettuce plants from big-vein-affected fields, whereas LBVaV was detected in lettuce plants not only from big-vein-affected fields but also from big-vein-free fields. LBVaV occurred widely at high rates in winter-spring lettuce-growing regions irrespective of the presence of MLBVV and, hence, of the presence of the big-vein disease.
米拉菲奥里生菜大脉病毒（MLBVV）和生菜大脉相关病毒（LBVaV）与生菜大脉病有关。区分这两种病毒对于阐明大脉病的病因至关重要。我们使用针对MLBVV和LBVaV的特异性抗体进行蛋白质免疫印迹，并利用MLBVV和LBVaV在黄瓜宿主反应以及生菜温度依赖性方面的差异，通过将每种病毒从双重感染的生菜植株转移到黄瓜或生菜植株上来分离这两种病毒。使一种无病毒的真菌分离物单独或同时获取这两种病毒。为了确认分离情况，将来自MLBVV、LBVaV和双重感染生菜植株的游动孢子连续12次用于生菜幼苗的系列接种。根据载体携带的病毒，每次转移时生菜幼苗分别单独感染MLBVV、单独感染LBVaV或同时感染两种病毒。仅感染MLBVV的生菜幼苗出现大脉症状，而仅感染LBVaV的生菜幼苗未出现症状。在田间调查中，在受大脉病影响的田块的生菜植株中始终检测到MLBVV，而LBVaV不仅在受大脉病影响的田块的生菜植株中被检测到，在无大脉病田块的生菜植株中也被检测到。LBVaV在冬春生菜种植区广泛且高发，无论MLBVV是否存在，因此无论大脉病是否存在。
