Scientists at the University of Cape Town, South Africa, and colleagues at the South African seed company, PANNAR Pty Ltd, have reportedly developed a resistant variety of maize that could alleviate both food shortages and promote genetically engineered (GE) foods in Africa.
The MSV-resistant maize is the first GE crop developed and tested solely by Africans.
According to Dr. Dionne Shepherd of the University of Cape Town, and her co-authors B. Owor, R. Edema, A. Varsani, D.P. Martin, J.A. Thomson and E.P. Rybicki, maize streak viruses (MSV) are Gemini-viruses that can destroy most of a maize crop.
They are endemic to sub-Saharan Africa and adjacent Indian Ocean islands where they are transmitted by leafhoppers in the genus Cicadulina.
Maize can supply 50 percent of the caloric intake in sub-Saharan Africa but, in certain years, a farmer's entire crop can be wiped out.
In their study presented at the annual meeting of the American Society of Plant Biologists in Chicago on Sunday, Shepher and her colleagues claimed that maize, which originated in Mexico, was carried to Africa in the 1500s and eventually displaced native food crops such as sorghum and millet. aize streak virus, an endemic pathogen of native African grasses, was then carried to maize plants by viruliferous leafhoppers.
They said that African scientists have been working for more than a quarter century on developing resistant varieties of maize by selecting and crossing varieties with various degrees of resistance to the virus.
They said the resistance to the virus requires multiple genes located on different chromosomes, thus ruling out a straightforward process.
The group at the University of Cape Town mutated a viral gene that encodes a protein that the virus needs to replicate itself and inserted it into maize plants. When the virus infects one of these transgenic maize plants, the mutated protein, which is expressed at a high level, prevents the virus from replicating and killing the plant.
The transgenic maize variety has proven consistently resistant to MSV and the trait can be reliably passed on to the next generation and in crosses to other varieties, they opined.
Field trials are scheduled to begin soon, not only to test the effectiveness of the technology in the field, but also to ensure that the GE maize variety has no unintended effects on beneficial organisms that may feed on it.
The resistant maize will also be tested to ensure that the viral protein is digestible and non-allergenic.