芸薹黄化病毒（BrYV）对油菜等十字花科作物的致病性及其引发症状形成的分子机理研究

Some poleroviruses are great threats to many crops all over the world, for example, Turnip yellows virus (TuYV) is the most significant pathogen on oilseed rape in European countries, which shows generally high level of infection and can cause at least 30 percent yield loss each year. Brassica yellows virus (BrYV) is a newly identified polerovirus, which is transmitted by Myzus persicae, occurs widely and has a vast range of cruciferous hosts, including the oilseed rape (B. napus ssp. napus) in China. BrYV has the closest taxonomy relationship with TuYV, and the symptoms caused by these two viruses on oilseed rape is very similar, however, we barely know anything about the pathogenicity and the mechanism of how they induce symptom development and reduce the yield. Therefore, Based on the research progress obtained on the poleroviruses infecting crucifer crops, this proposal will focus on BrYV pathogenicity and pathogenesis on cruciferous crops using basic biological assay and molecular biology techniques combination, our purpose is to prove our hypothesis that BrYV can also be of great economic importance in cruciferous crops, to dissect the viral determinants and host factors involved in pathogenesis, and finally elucidate the molecular mechanism for symptom development induced by BrYV on cruciferous crops especially oilseed rape. The results of this proposal would be helpful to not only find out effective integrated control strategy of crucifers viral diseases, but also provide useful experimental material and methods for further resistant variety breeding program.

马铃薯卷叶病毒属一些病毒对许多重要农作物在生产中造成严重危害。例如，芜菁黄化病毒 (TuYV )在欧洲各油菜产区大面积发生，每年对油菜产业造成至少30%产量损失。芸薹黄化病毒 (BrYV) 是申请人发现的该属一种新病毒，具有蚜虫传播和寄主范围广泛的特点，能够侵染油菜等十字花科植物。BrYV与TuYV的亲缘关系最近，且它们在田间侵染油菜之后所引发的症状非常类似，然而，对于BrYV 在油菜等十字花科植物上的致病性缺乏证据，BrYV和TuYV如何引发症状和降低产量的致病机理尚不清楚。因此，本申请课题在国内外已有研究工作基础上，利用基础生物学测定和多种分子生物学技术，深入研究BrYV 对于十字花科植物的致病性和症状形成机理，明确BrYV对于油菜等十字花科植物的重要性，解析与病程密切相关的病毒致病因子和寄主蛋白，揭示BrYV引发油菜等十字花科植物症状形成的致病分子机理。

芸薹黄化病毒 (Brassica yellows virus, BrYV) 是马铃薯卷叶病毒属的一种新病毒，具有蚜虫传播和寄主范围广泛的特点，能够侵染十字花科植物。本课题在国内外现有研究基础上，进一步明确了BrYV对十字花科植物具有很强的致病性，解析了转化BrYV全长cDNA的两个转基因拟南芥植株的转录组特征，验证BrYV全长cDNA转基因拟南芥花青素含量明显高于野生型拟南芥。初步判定MP蛋白是导致BrYV侵染后植物叶片颜色变紫的致病关键因子。初步明确了转化BrYV全长cDNA转基因拟南芥的小RNA特征。建立桃蚜传播BrYV方法，验证了自然情况下介体蚜虫传播病毒同样能够导致拟南芥表现出植株矮化和叶片变紫等异常发育表型和导致拟南芥花青素及糖类基因变化。利用酵母双杂方法筛选鉴定与BrYV MP蛋白互作的候选寄主蛋白。通过原核表达纯化蛋白制备了BrYV、PLRV等卷叶病毒属病毒MP的特异性抗血清，获得了BrYV部分基因的转基因材料。明确了病毒RNA沉默抑制子P0与寄主RAF2、SKP1互作在病毒侵染过程中的作用机制。上述研究结果为保障我国的油菜等十字花科作物的安全生产提供理论指导，并为抗病品种的选育提供实验材料。发表英文论文9篇（SCI论文6篇），会议论文摘要6篇，培养3位研究生获得博士学位，3位研究生获得硕士学位。