PNAS:华中农大姜道宏研究组发表真菌病毒进展
2016年10月24日，国际著名学术期刊《美国国家科学院院刊》杂志在线发表了华中农业大学植物科学技术学院姜道宏教授团队题为“Fungal DNA virus infects a mycophagous insect and utilizes it as a transmission vector”的研究论文，论文报道了真菌病毒及其生物防治的最新研究成果。博士研究生刘四为论文第一作者，姜道宏教授为论文通讯作者。
真菌病毒侵染真菌并在寄主细胞中复制，部分真菌病毒侵染植物病原真菌后导致寄主致病力减弱，这类病毒是重要的植物真菌病害生物防治资源。前人研究表明真菌病毒依赖于寄主的菌丝体融合进行水平传播，或者通过寄主产生的孢子进行垂直传播;在此之前没有关于真菌病毒传播介体的报道。
2010年该课题组首次报道真菌ssDNA病毒------核盘菌弱致病性相关DNA病毒1(Sclerotinia sclerotiorum hypovirulence-associated DNA virus 1, SsHADV-1)(Yu et al, 2010);之后他们发现SsHDAV-1病毒具有体外侵染能力及较好的油菜菌核病生物防治能力(Yu et al, PNAS, 2013)。最近进一步研究发现一种食真菌昆虫厉眼蕈蚊在取食感染SsHADV-1的核盘菌时，SsHADV-1可以进入厉眼蕈蚊体内并在昆虫细胞中复制积累;厉眼蕈蚊也可以将病毒传播给不携带病毒的核盘菌菌株，是SsHADV-1的传播介体。SsHADV-1与厉眼蕈蚊存在互惠性相互作用，一方面，SsHADV-1抑制核盘菌产生挥发性避虫物质(蘑菇醇和辛酮)，以吸引厉眼蕈蚊雌成虫趋向于携带病毒的核盘菌菌落中产卵，另一方面SsHADV-1可以显著提高厉眼蕈蚊的产卵能力。
该发现不仅促进了利用真菌病毒控制作物真菌病害的研究;同时也丰富了真菌病毒学研究，为研究真菌病毒、真菌与昆虫之间的互作关系提供了模型。此外，SsHADV-1代表着一类广泛分布于不同生境的新出现的环状小分子DNA病毒，本研究也将为解析这些新出现的环状小分子DNA病毒的生态学特性提供线索。据悉，该课题组于2014年也在真菌中发现和鉴定了一种真菌负链RNA病毒(Liu et al, PNAS, 2014)。
原文链接：
Fungal DNA virus infects a mycophagous insect and utilizes it as a transmission vector
原文摘要：
Mycoviruses are usually transmitted horizontally via hyphal anastomosis and vertically via sexual/asexual spores. Previously, we reported that a gemycircularvirus, Sclerotinia sclerotiorum hypovirulence-associated DNA virus 1 (SsHADV-1), could infect its fungal host extracellularly. Here, we discovered that SsHADV-1 could infect a mycophagous insect, Lycoriella ingenua, and use it as a transmission vector. Virus acquired by larvae feeding on colonies of a virus-infected strain of S. sclerotiorum was replicated and retained in larvae, pupae, adults, and eggs. Virus could be transmitted to insect offspring when larvae were injected with virus particles and allowed to feed on a nonhost fungus. Virus replication in insect cells was further confirmed by inoculating Spodoptera frugiperda cells with virus particles and analyzing with RT-PCR, Northern blot, immunofluorescence, and flow cytometry assays. Larvae could transmit virus once they acquired virus by feeding on virus-infected fungal colony. Offspring larvae hatched from viruliferous eggs were virus carriers and could also successfully transmit virus. Virus transmission between insect and fungus also occurred on rapeseed plants. Virus-infected isolates produced less repellent volatile substances to attract adults of L. ingenua. Furthermore, L. ingenua was easily observed on Sclerotinia lesions in rapeseed fields, and viruliferous adults were captured from fields either sprayed with a virus-infected fungal strain or nonsprayed. Our findings may facilitate the exploration of mycoviruses for control of fungal diseases and enhance our understanding of the ecology of SsHADV-1 and other newly emerging SsHADV-1–like viruses, which were recently found to be widespread in various niches including human HIV-infected blood, human and animal feces, insects, plants, and even sewage.
作者：姜道宏
