Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University, Nongda Road 1, Furong District, Changsha City, Hunan Province 410128, PR China; Key Laboratory of Grassland Ecosystem of Ministry of Education, Pratacultural Engineering Laboratory of Gansu Province, Sino-U.S. Centers for Grazingland Ecosystem Sustainability, College of Pratacultural Science, Gansu Agricultural University, Lanzhou 730070, PR China.
Yunnan Academy of Tobacco Agricultural Sciences, Kunming, Yunnan Province 650021, PR China.
Pestic Biochem Physiol. 2024 Sep;204:106042. doi: 10.1016/j.pestbp.2024.106042. Epub 2024 Jul 23.
Rhizoctonia solani is a widespread and devastating soil-borne plant fungal pathogen that causes diseases, including rice sheath blight, which are difficult to control. Some mycoviruses are potential biocontrol agents for the control of fungal diseases. In order to investigate the factors that influence the virulence of R. solani and search for mycoviruses with the potential for biocontrol of R. solani, a rice-infecting R. solani strain, ZJXD1-1, was isolated and confirmed to contain eight mycoviruses via dsRNA extraction and high-throughput sequencing. The identified mycoviruses belong to families of Endornaviridae (RsEV11 and RsEV12) and Mitoviridae (RsMV125 to RsMV129), and an unclassified Toti-like clade (RsTLV1). The C39 domain in RsEV12, which shares a close evolutionary relationship with bacteria, is observed for the first time in a mycovirus. Strains with different virus combinations were obtained through viral horizontal transfer, and pathogenicity test deduced that the Endornaviruses RsEV11 and RsEV12, and Mitovirus RsMV129 might potentially enhance the pathogenicity of R. solani, while RsMV125 might reduce the virulence or interfere with the function of other Mitoviruses. Furthermore, virus curing via protoplast regeneration and viral horizontal transfer demonstrated that RsMV129 is the causal agent of R. solani hypervirulence. Overall, our study provided the resource pool of viruses that may contribute to the discovery of new biocontrol agents against R. solani and enhance our understanding of the pathogenesis of R. solani regulated by mycoviruses.
腐霉菌是一种广泛存在且具有破坏性的土壤传播植物病原真菌，可引起多种疾病，包括水稻纹枯病，这些疾病难以控制。一些真菌病毒可能是真菌病害生物防治的潜在手段。为了研究影响腐霉菌毒力的因素，并寻找具有腐霉菌生物防治潜力的真菌病毒，我们从水稻中分离出并鉴定了一种腐霉菌菌株 ZJXD1-1，该菌株通过 dsRNA 提取和高通量测序被证实含有 8 种真菌病毒。鉴定出的真菌病毒属于 Endornaviridae 科（RsEV11 和 RsEV12）和 Mitoviridae 科（RsMV125 至 RsMV129），以及一个未分类的 Toti-like 分支（RsTLV1）。首次在真菌病毒中观察到与细菌具有密切进化关系的 RsEV12 中的 C39 结构域。通过病毒水平转移获得了具有不同病毒组合的菌株，致病性测试推断 Endornaviruses RsEV11 和 RsEV12 以及 Mitovirus RsMV129 可能潜在地增强腐霉菌的致病性，而 RsMV125 可能降低其毒力或干扰其他 Mitoviruses 的功能。此外，通过原生质体再生和病毒水平转移进行病毒清除实验表明，RsMV129 是腐霉菌超毒力的致病因子。总的来说，我们的研究提供了可能有助于发现新的腐霉菌生物防治手段的病毒资源库，并增强了我们对真菌病毒调控腐霉菌发病机制的理解。
