Obtenção de milho transgênico por RNAi resistente ao vírus do mosaico

Abstract

Brazil is the third largest maize producer in world. However, currently diseases that were not previously considered important are generating enormous losses such as the mosaic (caused by the SCMV). The crops infected with the virus can drop the productivity up to 50%. The search for more productive varieties, resistant to diseases and adapted to diverse cultivation conditions can be accelerated with techniques such as gene manipulation and transgenic. In this work, mosaic resistant transgenic maize lines were obtained by the RNA interference technology (RNAi). Friable callus of maize HiII were transformed via biolistic using a construction based a specific region on coat protein. T1 plants from 80 events were tested against the virus by 4 weeks consecutive mechanical inoculation. The results showed 20% of the T1 plants with no symptoms. The plants were also tested against sensitivity to PPT (selection marker). RT-PCR were done to confirm the presence of the virus on the asymptomatic plants and the expression the RNAi construction. Productivity comparison with no transgenic plants will be done as soon as homozygous with a single copy transgene is obtained. These results have indicated that the technique of RNAi is useful to generate virus-resistant transgenic maize plants.