Detection of adventitious presence of genetically modified seeds in lots of non transgenic soybean

Abstract

-The difficulty on identifying, lack of segregation systems and absence of suitable standards for coexistence of non trangenic and transgenic soybean are contributing for contaminations that occur during productive system. The objective of this study was to evaluate the efficiency of two methods for detecting mixtures of seeds genetically modified (GM) into samples of non-GM soybean, in a way that seed lots can be assessed within the standards established by seed legislation. Two sizes of soybean samples (200 and 400 seeds), cv. BRSMG 810C (non-GM) and BRSMG 850GRR (GM), were assessed with four contamination levels (addition of GM seeds, for obtaining 0.0%, 0.5%, 1.0%, and 1.5% contamination), and two detection methods: immunoassay of lateral flux (ILF) and bioassay (pre-imbibition into 0.6% herbicide solution; 25 ºC; 16 h). The bioassay is efficient in detecting presence of GM seeds in seed samples of non-GM soybean, even for contamination lower than 1.0%, provided that seeds have high physiological quality. The ILF was positive, detecting the presence of target protein in contaminated samples, indicating test effectiveness. There was significant correlation between the two detection methods (r = 0.82; p ≤ 0.0001). Sample size did not influence efficiency of the two methods in detecting presence of GM seeds.Index terms: Glycine max, glyphosate, transgenic.Detecção de presença adventícia de semente geneticamente modificada em lotes de soja não transgênica RESUMO -A dificuldade de identificação, a falta de sistemas de segregação e a ausência de normas adequadas à coexistência de soja não transgênica e transgênica têm contribuído para que ocorram contaminações durante as etapas do processo produtivo. O objetivo deste trabalho foi verificar a eficiência de dois métodos de detecção de misturas de sementes geneticamente modificadas (GM) em amostras de soja não transgênica, para avaliar lotes de sementes quanto aos limites da legislação. Foram avaliados dois tamanhos de amostra (200 e 400 sementes), das cultivares BRSMG 810C (não transgênica) e BRSMG 850GRR (GM), com quatro níveis de contaminação (sementes GM adicionadas para obter contaminações de 0,0%, 0,5%, 1,0% e 1,5%), e dois métodos de detecção: imunoensaio de fluxo lateral (IFL) e bioensaio (pré-embebição em solução do herbicida a 0,6%; 25 ºC; 16 h). O bioensaio é eficiente na detecção da presença de sementes GM em amostras de semente não transgênica, mesmo para contaminação inferior a 1,0%, desde que apresentem alta qualidade fisiológica. O IFL foi positivo, detectando a presença da proteína alvo nas amostras com contaminação, indicando a eficiência do teste. Houve correlação significativa entre os dois métodos utilizados (r = 0,82; p ≤ 0,0001). O tamanho da amostra não influenciou a eficiência dos dois métodos na detecção da presença de sementes GM.Termos para indexação: Glycine max, glifosato, transgênicos.

Seed reserve mobilization and seedling morphology in a bioassay for the detection of genetically modified soybean

“…In the case of glyphosate-tolerant cultivars, the highest concentration of the herbicide (0.12 %) affected the first and the final counts of germination, as observed by Pereira et al, (2018), however, the glyphosate-tolerant seedlings developed secondary roots, while the sensitive ones did not (Figure 1). The absence of secondary roots in glyphosate-sensitive seedlings is a striking feature of this bioassay (BERVALD et al, 2010;MELO;FAGIOLI;SÁ, 2013;PÁDUA et al, 2012). According to Albrecht et al (2014), the physiological quality and the vigor of the lots fall due to the concentration of the herbicide.…”

“…This is an interesting result because glyphosate-sensitive and glyphosate-tolerant cultivars could not be differentiated by ALR, but by W.1R; this was possible because the roots of tolerant seedlings are heavier (TORRES et al, 2003). In fact, the average root length does not include secondary roots, developed only by herbicide-tolerant cultivars, and absent or incipient in sensitive genotypes (FUNGUETTO et al, 2004;MELO;FAGIOLI;SÁ, 2013;PÁDUA et al, 2012). 11.8 * Averages followed by the same letter, uppercase in the horizontal and lowercase in the vertical, do not differ, at the level of 5 % probability.…”