State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, 712100 Yangling, China.
College of Plant Health and Medicine, Qingdao Agricultural University, 266109 Qingdao, China.
Proc Natl Acad Sci U S A. 2020 Feb 18;117(7):3779-3788. doi: 10.1073/pnas.1915996117. Epub 2020 Feb 3.
Plants and fungi are closely associated through parasitic or symbiotic relationships in which bidirectional exchanges of cellular contents occur. Recently, a plant virus was shown to be transmitted from a plant to a fungus, but it is unknown whether fungal viruses can also cross host barriers and spread to plants. In this study, we investigated the infectivity of Cryphonectria hypovirus 1 (CHV1, family ), a capsidless, positive-sense (+), single-stranded RNA (ssRNA) fungal virus in a model plant, CHV1 replicated in mechanically inoculated leaves but did not spread systemically, but coinoculation with an unrelated plant (+)ssRNA virus, tobacco mosaic virus (TMV, family ), or other plant RNA viruses, enabled CHV1 to systemically infect the plant. Likewise, CHV1 systemically infected transgenic plants expressing the TMV movement protein, and coinfection with TMV further enhanced CHV1 accumulation in these plants. Conversely, CHV1 infection increased TMV accumulation when TMV was introduced into a plant pathogenic fungus, In the in planta inoculation experiment, we demonstrated that TMV infection of either the plant or the fungus enabled the horizontal transfer of CHV1 from the fungus to the plant, whereas CHV1 infection enhanced fungal acquisition of TMV. Our results demonstrate two-way facilitative interactions between the plant and fungal viruses that promote cross-kingdom virus infections and suggest the presence of plant-fungal-mediated routes for dissemination of fungal and plant viruses in nature.
植物和真菌通过寄生或共生关系密切相关，在这种关系中会发生细胞内容物的双向交换。最近，一种植物病毒被证明可以从植物传播到真菌，但真菌病毒是否也能跨越宿主屏障并传播到植物中尚不清楚。在这项研究中，我们研究了 Cryphonectria hypovirus 1 (CHV1，家族)在模式植物中的感染性，CHV1 复制在机械接种的叶片中，但不会系统传播，但与不相关的植物 (+)ssRNA 病毒烟草花叶病毒 (TMV，家族)或其他植物 RNA 病毒共接种，可使 CHV1 系统感染植物。同样，CHV1 系统感染表达 TMV 运动蛋白的转基因植物，并且与 TMV 共感染进一步增强了这些植物中 CHV1 的积累。相反，当 TMV 被引入植物病原真菌中时，CHV1 感染会增加 TMV 的积累。在植物体内接种实验中，我们证明了无论是植物还是真菌感染 TMV，都能使 CHV1 从真菌水平转移到植物中，而 CHV1 感染增强了真菌对 TMV 的获取。我们的结果表明，植物和真菌病毒之间存在双向促进作用的相互作用，促进了跨领域病毒感染，并表明在自然界中存在植物-真菌介导的真菌和植物病毒传播途径。
