Determination of Amino Acids and Nutritional Aspects in Transgenic Soybean Exposed to Glyphosate

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With the increase of glyphosate tolerant transgenic soybean cultivation areas, this substance has become the main herbicide for this crop, its use may interfere with the metabolism and nutritional aspects of transgenic plants. In this scenario, the objective of this work was to verify the oil, protein, phytate and amino acid concentrations in glyphosate tolerant soybean cultivar. For this, a randomized block experiment with 6 treatments and 4 repetitions was performed. The analyzed cultivar was genetically modified soybean BRS Valiosa RR. The treatments consisted of glyphosate applied once, that is, respectively in the doses: 1,5 and 2,0 L ha-1 of the commercial product, glyphosate applied sequentially in the doses: 1,5 / 1,5; 2.0 / 1.5 and 2.0 / 1.5 / 1.5 L ha^-1 of commercial products, with intervals of 15 to 20 days between applications and control (clean) weeded (without glyphosate application)). Grains were harvested, macerated and 200 mg of each sample was used for extraction of soluble amino acids. After extraction, triplicate aliquots were analyzed to determine total soluble amino acids. For quantitative determination of free amino acids, reverse phase HPLC was used after derivatization with o-ophydialdehyde (OPA) on a Spherisorb ODS-2 (C18) column. OPA derivatives were detected by fluorescence and protein contents were determined by the Kjeldhal and Soxhlet method. The data obtained were submitted to analysis of variance and F test of the statistical program ASSISTAT version 7.7 beta. Significant analyzes were performed by comparing means by Tukey test at 5% probability. In conclusion, the data indicate that although the transgenic event affects some routes, amino acid synthesis was not affected nor in nutritional terms at the glyphosate doses studied.