title: Hypovirulence ofSclerotium rolfsiiCaused by Associated RNA Mycovirus.
abstract: Mycoviruses associated with hypovirulence are potential biological control agents and could be useful to study the pathogenesis of fungal host pathogens.Sclerotium rolfsii, a pathogenic fungus, causes southern blight in a wide variety of crops. In this study, we isolated a series of dsRNAs from a debilitatedS. rolfsiistrain, BLH-1, which had pronounced phenotypic aberrations including reduced pathogenicity, mycelial growth and deficient sclerotia production. Virus-curing and horizontal transmission experiments that eliminated or transmitted, respectively, all dsRNA elements showed that the dsRNAs were involved in the hypovirulent traits of BLH-1. Ultrastructure examination also showed hyphae fracture and cytoplasm or organelle degeneration in BLH-1 hyphal cells compared to the virus-free strain. Three assembled cDNA contigs generated from the cDNA library cloned from the purified dsRNA indicated that strain BLH-1 was infected by at least three novel mycoviruses. One has similarity to the hypovirulence-associated Sclerotinia sclerotiorum hypovirus 2 (SsHV2) in the familyHypoviridae, and the other two are related to two different unclassified dsRNA mycovirus families. To our knowledge, this is the first report ofS. rolfsiihypovirulence that was correlated with its associated dsRNA.
authors.affiliation: Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University Changsha, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhong
authors.affiliation: Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University Changsha, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Chen
authors.affiliation: Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University Changsha, China.
authors.forename: Hong J
authors.initials: HJ
authors.lastname: Zhu
authors.affiliation: Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University Changsha, China.
authors.forename: Bi D
authors.initials: BD
authors.lastname: Gao
authors.affiliation: Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University Changsha, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhou
keywords: Mycovirus; Sclerotium rolfsii; dsRNA; hypovirulence; hypovirus