Resumo

LANDAVAZO GAMBOA, Dora Alicia et al. Molecular and biological characterization of recombinant genes in maize landraces from Oaxaca. Agric. Téc. Méx [online]. 2006, vol.32, n.3, pp.267-279. ISSN 0568-2517.

Maize landraces from three regions: Sierra Norte, Valles Centrales and Costa in the state Oaxaca, were sampled looking for transgenic sequences. The strategies to accomplish this goal were: 1) search for 35 S promoter of the caulifl ower mosaic virus by qualitative PCR, 2) immunological detection of phosphinotricin acetyl transferase (PAT) enzyme activity, which confers resistance to the herbicides glufosinate, 3) detection of resistant plants to glufosinate, 4) detection of the transgene bar by PCR, 5) assessment of transgenic content by quantitative PCR and 6) sequencing of specific amplified fragments. The use of the first technique allowed for the detection of the 35S promoter sequence in plants from five plots from the Sierra Norte region, in the district of Ixtlan. The 35S promoter was not detected in samples from the other two regions. Immunological detection for the phosphinotricin acetyl transferase protein was negative for all samples analyzed. Twenty-three plants out of 1435 were resistant to the herbicide glufosinate; however, none showed amplification of the bar transgene. Out of fi ve initial samples only three were confi rmed positive for 35S promoter by quantitative PCR and sequencing. The 35S positive samples did not test positive for the bar transgen; therefore, the detected 35S promoter sequence might have a different origin as well as the herbicide resistance present in these maize landraces from the region Sierra Norte.

Palavras-chave : Zea mays L; cauliflower mosaic virus; glufosinate-ammonium; phosphinothricin acetyl transferase; real time PCR; 35S promoter.

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