Inhibition of maize streak virus (MSV) replication by transient and transgenic expression of MSV replication-associated protein mutants.
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.
Shepherd
Dionne N
DN
Department of Molecular and Cell Biology, University of Cape Town, Private Bag, Rondebosch, Cape Town 7701, South Africa.
Mangwende
Tichaona
T
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.
Martin
Darren P
DP
Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, Anzio Road, Cape Town 7925, South Africa.
Bezuidenhout
Marion
M
Department of Molecular and Cell Biology, University of Cape Town, Private Bag, Rondebosch, Cape Town 7701, South Africa.
Thomson
Jennifer A
JA
Department of Molecular and Cell Biology, University of Cape Town, Private Bag, Rondebosch, Cape Town 7701, South Africa.
Rybicki
Edward P
EP
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.
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*
D014764:Viral Proteins