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RNAi-Mediated Resistance to Bean golden mosaic virus in Genetically Engineered Common Bean (Phaseolus vulgaris)

June 2007 , Volume 20 , Number  6
Pages  717 - 726

Kenny Bonfim , 1 , 2 Josias C. Faria , 3 Elsa O. P. L. Nogueira , 1 érica A. Mendes , 1 and Francisco J. L. Aragão 1 , 2

1Embrapa Recursos Genéticos e Biotecnologia, PqEB W5 Norte, 70770-900, Brasília, DF, Brazil; 2Universidade de Brasília, Departamento de Biologia Celular, Campus Universitário, 70910-900, Brasília, DF, Brazil; 3Embrapa Arroz e Feijão, Rodovia GO-462, km 12 Zona Rural C.P. 179, 75375-000 Santo Antônio de Goiás, GO, Brazil

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Accepted 24 January 2007.

Bean golden mosaic virus (BGMV) is transmitted by the whitefly Bemisia tabaci in a persistent, circulative manner, causing the golden mosaic of common bean (Phaseolus vulgaris L.). The characteristic symptoms are yellow-green mosaic of leaves, stunted growth, or distorted pods. The disease is the largest constraint to bean production in Latin America and causes severe yield losses (40 to 100%). Here, we explored the concept of using an RNA interference construct to silence the sequence region of the AC1 viral gene and generate highly resistant transgenic common bean plants. Eighteen transgenic common bean lines were obtained with an intron-hairpin construction to induce post-transcriptional gene silencing against the AC1 gene. One line (named 5.1) presented high resistance (approximately 93% of the plants were free of symptoms) upon inoculation at high pressure (more than 300 viruliferous whiteflies per plant during the whole plant life cycle) and at a very early stage of plant development. Transgene-specific small interfering RNAs were detected in both inoculated and non-inoculated transgenic plants. A semiquantitative polymerase chain reaction analysis revealed the presence of viral DNA in transgenic plants exposed to viruliferous whiteflies for a period of 6 days. However, when insects were removed, no virus DNA could be detected after an additional period of 6 days.

Additional keywords: Begomovirus, geminivirus, RNA interference.

© 2007 The American Phytopathological Society