发现首例真菌DNA病毒

5月4日，国际权威刊物《美国科学院院刊》（PNAS）发表了华中农业大学微生物学国家重点实验室姜道宏教授研究小组的研究论文，报告了他们在真菌中发现的DNA病毒（SsHADV-1）。这是国际上首次有关真菌DNA病毒报道。

感染真菌并在其体内增殖的病毒称为真菌病毒。目前，真菌中已发现的所有真菌病毒均为RNA病毒，甚至有学者认为真菌中可能存在一种可抑制DNA病毒复制和增殖的特殊机制。华中农业大学植物病理学专业硕士生于晓和博士生李博，自油菜菌核病病原菌核盘菌致病力衰退菌株DT-8中分离鉴定出DNA病毒，解开了多年来真菌中是否存在DNA病毒的谜团。

核盘菌DNA病毒与普遍危害作物的植物双生病毒具有亲缘关系。据姜道宏介绍，中国农作物由双生病毒引起的病害十分严重，如黄化曲叶病毒病对番茄具有毁灭性危害，发病植株不能正常开花或花蕊脱落，最后罹病植株枯死。从南到北全国15个省市都有发生，仅2009年经济损失达数十亿元。防治该类病毒危害的关键的基础研究双生病毒的起源和进化问题，至今仍然是一个谜团。核盘菌DNA病毒类似于双生病毒进化中较早祖先的结构特点，为双生病毒的起源和进化研究提供了新的科学证据。

姜道宏还介绍说，在生产实践上，致病力衰退相关的真菌病毒可以用于植物病害生物防治，寻找这一类病毒是国内外生物防治学者致力研究的重要方向之一。

核盘菌DNA病毒的致病力衰退特性在控制作物真菌病害尤其是核盘菌导致的菌核病上具有潜在的优势。核盘菌可以侵染450多种植物，其引起的菌核病严重威胁到油菜和大豆等多种作物的安全生产。研究人员下一步将开展利用真菌DNA病毒，防治油菜等作物菌核病等多项研究。

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A geminivirus-related DNA mycovirus that confers hypovirulence to a plant
pathogenic fungus
Xiao Yua,b,1, Bo Li ^a,b, Yanping Fu ^b, Daohong Jiang ^a,b, Said A. Ghabrial ^c, Guoqing Li ^a,b,
Youliang Peng ^d, Jiatao Xie ^b, Jiasen Cheng ^b, Junbin Huang ^b, and Xianhong Yi ^b

a. State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, Hubei Province, China;
b. Provincial Key Laboratory of Plant Pathology of Hubei Province, Huazhong Agricultural University, Wuhan 430070, Hubei Province, China;
c. Department of Plant Pathology, University of Kentucky, Lexington, KY 40546-0312; and
d. State Key Laboratories for Agrobiotechnology, China Agricultural University, Beijing 100193, China

【Abstract】Mycoviruses are viruses that infect fungi and have the potential to control fungal diseases of crops when associated with hypovirulence. Typically, mycoviruses have double-stranded (ds) or single-stranded (ss) RNA genomes. No mycoviruses with DNA genomes have previously been reported. Here, we describe a hypovirulence-associated circular ssDNA mycovirus from the plant pathogenic fungus Sclerotinia sclerotiorum. The genome of this ssDNA virus, named Sclerotinia sclerotiorum hypovirulence-associated DNA virus 1 (SsHADV-1), is 2166 nt, coding for a replication initiation protein (Rep) and a coat protein (CP). Although phylogenetic analysis of Rep showed that SsHADV-1 is related to geminiviruses, it is notably distinct from geminiviruses both in genome organization and particle morphology. Polyethylene glycol-mediated transfection of fungal protoplasts was successful with either purified SsHADV-1 particles or viral DNA isolated directly from infected mycelium. The discovery of an ssDNA mycovirus enhances the potential of exploring fungal viruses as valuable tools for molecular manipulation of fungi and for plant disease control and expands our knowledge of global virus ecology and evolution.