title: Inhibition of maize streak virus (MSV) replication by transient and transgenic expression of MSV replication-associated protein mutants.
abstract: Maize streak disease is a severe agricultural problem in Africa and the development of maize genotypes resistant to the causal agent, Maize streak virus (MSV), is a priority. A transgenic approach to engineering MSV-resistant maize was developed and tested in this study. A pathogen-derived resistance strategy was adopted by using targeted deletions and nucleotide-substitution mutants of the multifunctional MSV replication-associated protein gene (rep). Various rep gene constructs were tested for their efficacy in limiting replication of wild-type MSV by co-bombardment of maize suspension cells together with an infectious genomic clone of MSV and assaying replicative forms of DNA by quantitative PCR. Digitaria sanguinalis, an MSV-sensitive grass species used as a model monocot, was then transformed with constructs that had inhibited virus replication in the transient-expression system. Challenge experiments using leafhopper-transmitted MSV indicated significant MSV resistance--from highly resistant to immune--in regenerated transgenic D. sanguinalis lines. Whereas regenerated lines containing a mutated full-length rep gene displayed developmental and growth defects, those containing a truncated rep gene both were fertile and displayed no growth defects, making the truncated gene a suitable candidate for the development of transgenic MSV-resistant maize.
authors.affiliation: Department of Molecular and Cell Biology, University of Cape Town, Private Bag, Rondebosch, Cape Town 7701, South Africa.
authors.forename: Dionne N
authors.initials: DN
authors.lastname: Shepherd
authors.affiliation: Division of Pharmacology, University of Cape Town, Cape Town, South Africa.|Department of Molecular and Cell Biology, University of Cape Town, Private Bag, Rondebosch, Cape Town 7701, South Africa.
authors.forename: Tichaona
authors.initials: T
authors.lastname: Mangwende
authors.affiliation: Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, Anzio Road, Cape Town 7925, South Africa.
authors.forename: Darren P
authors.initials: DP
authors.lastname: Martin
authors.affiliation: Department of Molecular and Cell Biology, University of Cape Town, Private Bag, Rondebosch, Cape Town 7701, South Africa.
authors.forename: Marion
authors.initials: M
authors.lastname: Bezuidenhout
authors.affiliation: Department of Molecular and Cell Biology, University of Cape Town, Private Bag, Rondebosch, Cape Town 7701, South Africa.
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Thomson
authors.affiliation: Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, Anzio Road, Cape Town 7925, South Africa.|Department of Molecular and Cell Biology, University of Cape Town, Private Bag, Rondebosch, Cape Town 7701, South Africa.
authors.forename: Edward P
authors.initials: EP
authors.lastname: Rybicki
mesh_terms: D015870:Gene Expression; D026762:Maize streak virus / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D030821:Plants, Genetically Modified; D014764:Viral Proteins / Q000502:physiology*; D014779:Virus Replication / Q000502:physiology*
chemical_list: D014764:Viral Proteins