黄瓜花叶病毒M株系引致烟草症状恢复的初步研究

Primary studies on symptom recovery of tobacco plants infected by Cucumber mosaic virus strain M

黄瓜花叶病毒M株系在白肋烟上具有典型的症状恢复现象,本研究用提纯病毒和DAS-ELISA建立了CMV-M病毒定量检测方法。研究发现,症状严重程度与叶片中的病毒浓度呈正相关:最早发病的黄化叶每克病组织中病毒可高达790μg,而恢复叶片上部再发病的花叶症状病叶中每克病组织中病毒也可高达508μg,恢复叶片中病毒含量很低,每克叶片中最高也没有超过6μg,仅为发病叶片病毒浓度的1/85～1/135,远低于根和茎中的病毒浓度。RT-PCR和生物学检测结果表明恢复叶片中确实存在具侵染活性的病毒,而且病毒在长达半个月以上一直保持很低浓度。结果表明恢复叶中可能存在有效的病毒防御机制,其具体机理有待进一步研究。

A typical symptom recovery appears on tobacco （Nicotiana tabacum cv. white Budey） plants infected with Cucumber mosaic virus strain M （CMV-M）. It is a significant step for finding of symptom recovery mechanism of virus infection if the variation of virus concentration in tobacco plants infected with CMV- M is demonstrated. A quantitative method for detection of CMV-M was established by purified CMV particles and DAS-ELISA. The results showed that the virus concentration was positively related to severity of symptoms, with the highest up to 790 μg/g tissue in the first appeared yellow symptom leaves, up to 508 μ/g tissue in the upper mosaic symptom leaves; and only 6 μg/g tissue in the recovery symptomless middle leaves, which was about 85 to 135 times less than that in the mosaic or yellow symptom leaves and also much lower than that in the stems and roots. RT-PCR and biological experiment showed that infectious virus did exist in the recovered leaves, but somehow the virus could not reach higher concentration and cause obvious symptom, it indicated that an efficient resistant mechanism existed in symptom recovery leaves.