Biotech Updates

Transgenic Sweet Potato to Battle Virus Diseases in South Africa

April 30, 2014

Infection of sweet potato by multiple viruses is a common occurrence and often results as a more severe disease than the sum effect of infection with each virus alone. The sweet potato feathery mottle virus (SPFMV), sweet potato chlorotic stunt virus (SPCSV), sweet potato virus G (SPVG) and Sweet potato mild mottle virus (SPMMV) have caused a synergistic disease complex that has devastated sweet potato in South Africa. In order to address the problem, transgenic sweet potato (Ipomoea batatas Lam.) with broad virus resistance is being developed through genetic engineering.

Transformation of apical tips of sweet potato cultivar Blesbok was achieved through Agrobacterium tumefaciens strain LBA4404. Coat protein gene segments of the four viruses were used to induce gene silencing in transgenic sweet potato. Six transgenic plants were developed and these six were then evaluated through graft inoculation with SPFMV, SPCSV, SPVG and SPMMV-infected Ipomoea setosa. Virus presence was detected in the transgenic sweet potatoes using nitrocellulose enzyme-linked immunosorbent assay. However, all transgenic plants displayed delayed and milder symptoms of chlorosis and mottling of lower leaves compared to the control plants.

These results showed promise and require further investigation on resistance to virus infections under field conditions.

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