RESUMO
MZHG0JG corn will offer growers the flexibility to alternate between herbicides with two different modes of action in their weed-management programs, helping to mitigate and manage the evolution of herbicide resistance in weed populations. The proteins conferring herbicide tolerence in MZHG0JG corn, double-mutated 5-enol pyruvylshikimate-3-phosphate synthase protein (mEPSPS) and phosphinothricin acetyltransferase (PAT), as well as the MZHG0JG corn event, have been assessed by regulatory authorities globally and have been determined to be safe for humans, animals, and the environment. In addition to the safety data available for these proteins, further studies were conducted on MZHG0JG corn to assess levels of mEPSPS as compared to previously registered genetically modified (GM) corn. The results support the conclusion of no impact on toxicological safety or nutritional composition.
Assuntos
3-Fosfoshikimato 1-Carboxiviniltransferase/genética , Acetiltransferases/genética , Proteínas de Bactérias/genética , Plantas Geneticamente Modificadas/genética , Zea mays/genética , 3-Fosfoshikimato 1-Carboxiviniltransferase/metabolismo , Acetiltransferases/metabolismo , Agrobacterium tumefaciens/enzimologia , Proteínas de Bactérias/metabolismo , Análise de Perigos e Pontos Críticos de Controle , Resistência a Herbicidas , Herbicidas/farmacologia , Mutação , Valor Nutritivo , Plantas Geneticamente Modificadas/efeitos adversos , Plantas Geneticamente Modificadas/efeitos dos fármacos , Plantas Geneticamente Modificadas/metabolismo , Streptomyces/enzimologia , Zea mays/efeitos adversos , Zea mays/efeitos dos fármacos , Zea mays/metabolismoRESUMO
The enzyme p-hydroxyphenylpyruvate dioxygenase (HPPD) is ubiquitous in plants and functions in the tyrosine catabolic pathway, resulting in the formation of homogentisate. Homogentisate is the aromatic precursor of all plastoquinones and tocochromanols, including tocopherols and tocotrienols. Soybean (Glycine max (L.) Merr.) has been genetically modified to express the gene avhppd-03 that encodes the protein AvHPPD-03 derived from oat (Avena sativa L.). The AvHPPD-03 isozyme has an inherent reduced binding affinity for mesotrione, a herbicide that inhibits the wild-type soybean HPPD enzyme. Expression of avhppd-03 in soybean plants confers a mesotrione-tolerant phenotype. Seeds from three different avhppd-03-expressing soybean events were quantitatively assessed for content of eight vitamin E isoforms. Although increased levels of two tocopherol isoforms were identified for each of the three soybean events, they were within, or not substantially different from, the ranges of these isoforms found in nontransgenic soybean varieties. The increases of these tocopherols in the avhppd-03-expressing soybean events may have a slight benefit with regard to vitamin E nutrition but, given the commercial processing of soybeans, are unlikely to have a material impact on human nutrition with regard to vitamin E concentrations in soybean oil.
