Detection of GT73 glyphosate-resistance transgene in wild Brassica rapa populations from Argentina and fitness evaluation

ALONSO, ALDANA; PANDOLFO, CLAUDIO; ACCATINO, ORNELLA; URETA, SOLEDAD; PRESOTTO, ALEJANDRO

Foz de iguazu

Congreso; International Congress of Genetics; 2018

Sociedad BArsilera de Genetica

Brassica rapa L. is an annual Brassicaceae species cultivated for oil and food production, whose wild form is a weed of crops worldwide. In the Argentine Pampas region this species is widely distributed. B. rapa is one of the progenitors of the amphidiploid species B. napus (oilseed rape, canola), one of the most important sources of vegetable oil. Genetically modified (GM) B. napus cultivars are currently grown in 8.6 MHa of five countries, but forbidden in Argentina. However, in 2012, wild populations of glyphosate-resistant B. rapa were found in southeastern Buenos Aires Province. The objective of this work was to confirm the transgenic origin of glyphosate resistance in these populations and to evaluate its fitness cost. Plants of five different wild B. rapa populations were evaluated to detect the GT73 transgene that confers glyphosate resistance in GM oilseed rape, using the specific primers for the CP4 EPSPS gene. The fitness cost of the transgene in one of these populations was evaluated for two years, selecting plants with and without the trait, using an immunological quick test. Plants of five different wild B. rapa populations amplified the 108-bp fragment corresponding to the GT73 event, which is consistent with the occurrence of glyphosate resistance. No difference where found between plants with and without the transgene in several fitness traits, including yield per plant. Our results suggest that the transgene does not imply a fitness cost in this B. rapa population and its dispersion in environments without selection pressure would not be limited.