病毒病是造成山药产量下降、品质降低和种性退化的主要原因。2013-2014年，云南发现一种轻度花叶和斑驳的山药病毒病，根据对病毒基因组和编码的氨基酸序列分析，可将该病毒列为与日本山药花叶病毒（JYMV）具有较近亲缘关系的新病毒。因缺乏有效的生物学测试，病毒最终被认为是与JYMV具有较大变异的分离物(JYMV-CN)。本项目拟通过传统的生物学实验，测试病毒的传播途径、寄主范围和症状类型，明确病毒的分类地位。分离、纯化不同地区，不同寄主品种上的病毒分离物，通过接种实验，分析病毒相同分离物在不同寄主品种上，和同一分离物在相同寄主品种上的症状表现，筛选病毒的弱毒株系。结合基因组全序列，分析病毒的分子变异与致病性的相关性。利用病毒粒体，或经原核表达诱导cp基因表达产生的蛋白为抗原制备单克隆抗体，建立病毒基于血清学的检测方法。所获得的研究结果将对该病毒病害的诊断和防控提供科学的理论依据和技术指导。

Viruses are the most devastating pathogen that deleterious effects on yam tuber yield, quality and germplasm. A virus induced mild mosaic and foliar mottle of yam was found in Yunnan during 2013-2014. Analysis of its’ complete nucleotide sequence and polyprotein encoded, the virus should be classified as a new potyvirus with phylogenetic relationship to Japanese yam mosaic virus (JYMV), but for lacking effective biological testing ,it was taken as a novel strain of JYMV in China (JYMV-CN). With traditional biological method, study of this proposal will be definite the classification of the virus base on property of the virus transmission, host range and symptoms induced. Isolations represent different region, and different yam species will be separated and purified, followed with inoculation to test those symptoms induced by same isolations in different yam species, or by different isolations in the same yam species. Results of the work is that the mild strain of the virus will be selected. Molecular variation and phylogenetic differentiation of the virus will also be analysis conducted by sequencing of different isolates. Monoclonal antibody against JYMV-CN used in serological detection will be provided with virions of purification and/or Coat Protein induced by prokaryotic expression with CP gene. Results of this proposal will provide technical support for the diagnosis and scientific prevention and control of the virus in fields.