Wang Ya Rong, Chen Yi, Li Chang Xin, Li Xiao Gang, Zhu Jun Zi, Zhong Jie
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, Colleage of Pratacultural Science, Gansu Agricultural University, Lanzhou 730070, China.
Yunnan Academy of Tobacco Agricultural Sciences, Kunming, Yunnan Province 650021, PR China.
Pestic Biochem Physiol. 2025 Nov;214:106576. doi: 10.1016/j.pestbp.2025.106576. Epub 2025 Jul 15.
The genus Alternaria comprises a wide range of ubiquitous plant pathogens that affect various host plants. Certain mycoviruses can induce changes in the biological characteristics and virulence of host fungi, offering potential for biocontrol in managing fungal plant diseases. Here, we identified a mycovirus with a high degree of homology to Alternaria arborescens victorivirus 1 (AaVV1), which was previously reported from Alternaria arborescens, in the QRH strain of the heterologous host Alternaria gomphrenae. This virus was named AaVV1-QRH and belongs to the Victorivirus genus within the family Totiviridae. Isometric particles, containing dsRNA genome, 30 to 45 nm in diameter, were examined by TEM. Virus curing through protoplast regeneration and biological comparison demonstrated that AaVV1-QRH might reduce the virulence and inhibit the growth of its A. gomphrenae host. Furthermore, following the addition of cell-free culture supernatant from strain QRH, A. alternata was successfully transfected with virus AaVV1-QRH, resulting in the conversion to a hypovirulent strain, as further confirmed by viral horizontal transfer between A. alternata strains and virulence analysis. Collectively, our study provided clear evidence that AaVV1-QRH was the causal agent of hypovirulence in both the A. gomphrenae and A. alternata, which may not only serve as a potential biocontrol agent against Alternaria species but also offer insights into the pathogenesis of Alternaria fungi.
