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Risk Assessment
Record information and status
Record ID
48255
Status
Published
Date of creation
2009-02-18 13:58 UTC (pafca@mre.gov.br)
Date of last update
2013-04-22 21:44 UTC (gutemberg.sousa@mctic.gov.br)
Date of publication
2013-04-23 20:34 UTC (davi.bonavides@itamaraty.gov.br)

This document is also available in the following languages:
General Information
Country
  • Brazil
Title of risk assessment
Risk Assessment of Insect Resistant Maize (TC 1507)
Date of the risk assessment
2008-12-11
Competent National Authority(ies) responsible for the risk assessment
National Technical Biosafety Commission
Setor Policial Sul -SPO Área 5 Quadra 3 Bloco B - Térreo Salas 10 à 14
Brasília, DF
Brazil, CEP - 70610-200
Phone:(5561) 3411-5516
Fax:(5561) 3317-7475
Email:ctnbio@mct.gov.br
Url:National Technical Biosafety Comission
Risk assessment details
Living modified organism
DAS-Ø15Ø7-1 - Herculex™ I maize
Resistance to diseases and pests - Insects - Lepidoptera (butterflies and moths) Resistance to herbicides - Glufosinate
Show detection method(s)
Scope of the risk assessment
  • LMOs for Contained use
  • LMOs for direct use as feed
  • LMOs for direct use as food
  • LMOs for Introduction into the environment
    • Commercial production
    • Field trial
  • LMOs for processing
Methodology and points to consider
Potential adverse effects identified in the risk assessment
Analyses of TC1507 corn regarding quality and quantity standards of metabolites normally found in corn demonstrated that event TC1507 is substantially equivalent to conventional varieties of corn. The assessments were conducted to define individual components that are part of human diet. Centesimal composition  data analyses presented in the process encompass profile analysis of proteins, amino acids, fat acids, lipids, carbohydrates, minerals, vitamins, secondary metabolites,  and composition of fodder and kernel, comparing event TC1507 with corn plants not genetically modified. The results obtained in Brazil and other countries failed to show variations that exceed the standards commonly found in non-genetically modified corn hybrids and lineages. Therefore, one may assume that TC1507 corn is substantially equivalent to non-genetically modified corn plants. Samples taken from leaves, pollen, kernel and the whole plant (vegetative tissues) of both, TC1507 and conventional corn lineages, were used to detect Cry1F and PAT proteins in transformed plants. Western Blot analyses showed that protein Cry1F is expressed in all tissues, in contrast to protein PAT that was detected only in leaves of the TC1507 lineage. In order  to analyze the level of  expression, samples  of corn leaves, pollen, silk, stalk, whole plant, kernel, both normal and senescent  of the TC1507 corn lineage, as well as  samples  from non-transformed corn plants  were collected during the 1998-1999  crop and  tested with the ELISA test. The results regarding total protein (TP) showed higher levels of the Cry1F protein expression in the whole plant (1063.8 pg Cry1F/ug TP), senescent whole plant (714.3 pg Cry1F/ug TP), stalk (550.0 pg Cry1F/ug TP) followed by pollen (135.5 pg Cry1F/ug TP), leaf (110.0 pg Cry1F/ug TP), grain (89.9pg Cry1F/ug TP) and silk (50.3 pg Cry1F/ug TP). Dispersion of corn seeds is easily controlled, since domestication of corn eliminated the ancient seed dispersion mechanisms and pollen movement is the only effective means for gene escaping of corn plants. Horizontal gene flow between TC1507 corn and other species, even those closely related, are practically unlikely to happen, since wile species related to corn do not occur naturally in Brazil. Coexistence between cultivars of conventional corn (either cultivated or Creole) and transgenic cultivars is possible from the agronomic viewpoint, and this is a reason to comply with the provisions of CTNBio Ruling Resolution no. 04.
Likelihood that the potential adverse effects will be realized
Considering that TC1507 corn is derived from a transformation of common Zea mays corn, a fully characterized species with a  solid history of safety  for  human and animal  consumption; that the transformation process caused insertion of a  single  copy of a DNA fragment containing genetic constructs with pat and cry1f  genes
Possible consequences:
1. Corn is the species that reached the highest domestication level among cultivated plants, and is  unable to survive  in nature with no human intervention.
2. In Brazil, there are no wild species with which corn may intercross, since  the closest wild corn species is teosinte, found only in Mexico and in some Central America locations, where it may cross  with corn cultivated in production fields.
3. Protein Cry1F was detected in low levels  in tissues analyzed and displayed  high  susceptibility to digestion in simulated gastric fluids, failing  to show acute toxicity in mammals and similarity with known  allergens(38).
4. The DNA molecule is  a natural  component of food and there is no  evidence that this molecule may have adverse effect  to man when ingested  in food  in acceptable amounts.
5. There is no evidence that intact  genes of plants may be  transferred and functionally integrated to the human genome or genome of  other mammals exposed to such DNA or to foods manufactured with such elements(50).
6. Applicant answered to all questions mentioned in CTNBio Ruling Instruction  no. 05 and there is no issue indicating that this corn may present  adverse  effects to human and animal health.
7. There  is no likelihood  that TC1507 corn may perform  or cause invasion  of uncultivated areas.
8. Proteins Cry1F and PAT  are  rapidly degraded in gastric conditions, thus  minimizing any absorption potential in an intestinal system(51, 40).
9. Bacterium B. thuringiensis may be considered the most potent biological agent to control forest and agricultural pest insects and disease vectors for  the specificity of delta-endotoxins to insects and target-invertebrates, and its innocuousness to  vertebrates and the environment, including  beneficial insects and natural enemies,  making this agent a key component in integrated management of pests.
10. Cultures of B. thuringiensis are filed with Agência Nacional de Vigilância Sanitária - ANVISA, the National  Sanitary Surveillance Agency, under  different formulations for application in thirty types of plant  cultures  for food  use(68).
11. Biopesticides  based on such toxin are widely used as an alternative to chemical insecticides in terms  of safety to non-target organisms and when  development of resistance to chemical insecticides is the  case(69).
12. The use of Bt technology in Brazil may contribute to  reduce  the use of insecticides and, consequently,  mitigate  the impact resulting from the  use of  such pesticides  to the environment, human and  animal  health, and to positively affect the preservation of non-target  organisms and beneficial  insects, facilitating the integrated management of farm pests.
13. This corn variety shows low risk to human health, animal health  and is no likely to change into a  plant pest.
14. The gene insertion did  not change the composition and  nutritive value and the presence of protein Cry1F in proportion to the total corn protein does not imply significant contribution to the amount or proteins in human diet.
15. Nutritional, equivalence and toxicological tests have  been reported showing the expressed protein to be innocuous(26, 27, 28).
16. Concurrently to resistance to insects, the Bt toxin contributes to reduce mold  development in corn ears, which are responsible for production and  contamination of corn  with mycotoxins(29).
17. No  other characteristic  of the  original organisms that represents risks to human health was modified and there  was no record  of adverse effects resulting from  TC1507 corn in studies related to human health and the environment.
18. Commercial use of TC1507 corn lineage is occurring  in the United States since 2001, Argentina (2005), Colombia (2006), China (2004), Mexico (2003), South Africa (2002), Canada (2002), Australia (2003), Japan (2002), Korea (2002), Philippines (2003), Taiwan (2003)  and European Union (2006)  without  any record of problems linked to the agronomic characteristics of the event.
19. Comments, opinions, suggestions and documents resulting from a Public Hearing related to  TC1507 corn held on March 20, 2007, failed to register any relevant scientific fact, corroborated by scientific evidence, that may compromise the environmental safety and  human and animal  health.
20. Coexistence of  conventional  corn cultivars (improved or Creole) and transgenic cultivars is  possible from  the agronomic viewpoint, and the provisions  of CTNBio Ruling Instruction no. 04 shall be complied  with.
For the foregoing, and  considering internationally accepted criteria in the process of  risk analysis  for  genetically modified raw-materials, a conclusion  emerges that TC1507 corn is as safe as  its conventional  equivalent.
CTNBio holds that commercial cultivation and consumption of TC1507 corn are not potential causes of significant degradation to the environment or of harm to human and animal health. Restrictions to the use of the GMO analyzed and its derivatives are conditioned to the provisions of CTNBio Ruling Resolutions no. 03 and 04. Additionally, this risk analysis took into consideration and consulted third party  independent studies and scientific publication submitted by applicant.
Receiving environment(s) considered
Corn is an annual plant with low dormancy ability. The corn seed can survive from one cultivation season to another, and may successfully germinate under adequate temperature and moist conditions. These so-called  volunteer plants are easily  identified and controlled by manual, mechanical and chemical means. Corn does not exhibit tendency to proliferate as a plant pest and is not invasive in natural ecosystems(45).  Some species of the Zea genus are sylvan plants developing successfully in Central America without any considerable trend to proliferate as a plant pest.
Event TC1507 was carefully cultivated and monitored in what regards its proliferation ability as plant pest and agronomic behavior in over eighty locations around the world, including Argentina, United States, Chile, Italy, Brazil, France and South Africa. In Brazil, several planned  releases to the environment were presented by applicants and duly passed by CTNBio. In all  cases, TC1507 corn exhibited a behavior similar to the one expected from non-transgenic  corn, without evidencing any development of unforeseen morphologic or phenotypic characteristics.
In experimental and field essays conducted in Brazil by Dow AgroSciences during the 2005-2006 crops to compare TC1507 corn with the conventional material, several agronomic parameters were measured, such as: plant height, ear, stalk breaking, root size and yield, among other agronomic characteristics and resistance to diseases. Results reached in  experiments conducted in domestic soil were comparable to those attained in Argentina and United States, where it was demonstrated that the genetic  modification does not affect  the plant phenotype and field behavior.
Experimental essays conducted  all over  the  world with TC1507 corn lineage since 1997 confirmed that event TC1507 does not  show any unexpected change in plant vigor. Assessment by simple observation of  field essays showed  that the development from an emerging  plantlet to one-leaved plantlet, and from three to  five  leaves plantlet, TC1507 corn lineage is  comparable to the non-genetically modified corn.
Applicants additionally conducted field essays in Brazil, where resistance  to  common rust (Puccinia sorghi), Polysora rust (Puccinia Polysora),  cercosporiosis (Cercospora zea-maydis), Northern corn leaf blight (Exserohilum turcicum), Phaeosphaeria leaf spot (Phaeosphaeria  maydis), and Diplodia leaf spot (Diplodia macrospora) was assessed. The data indicate that in the four hybrid essayed there was no differences in disease severity between the hybrid  with TC1507 event and the correspondent conventional hybrid.
Comparatively, essays were conducted to assess  resistance characteristics  of hybrids derived from TC1507 corn lineage and their corresponding non-genetically modified corn to diseases such as Exserohilum turcicum leaf spot, Bipolaris maydis   leaf spot, Polysora  rust, cercosporiosis, Erwinia stewartii bacterial spot,  Ustilago zeae smut and resistance to pests, such as armyworm Spodoptera frugiperda, corn earworm Helicoverpa zea,  Frankliniella sp. thrips, Aphis sp. aphis, Chaetocnema pulicaria corn flea beetle, red acarus, among others. These essays showed that there was no difference to be recorded on severity of disease symptoms; damage caused by insects, except for organisms identified as susceptible to protein Cry1F among plants of event TC1507 and those of genetically modified corn.
The biological activity of protein Cry1F was studied in a range of pest insects feeding on corn plants. The essays were conducted  by exposing insects to artificial diets  treated with aqueous formulations of Cry1F  protein produced from a microbial source (P. fluorescens). Evans(51) showed  that the biochemical characteristics of a protein produced in either plant or microbial  form are equivalent. Insects studied were: armyworm (Spodoptera Frugiperda), moth borer (Diatraea saccharalis),  European corn borer (Ostrinia nubialis), corn earworm (Helicoverpa zea), black cutworm (Agrotis ipsilon), lesser cornstalk borer (Elasmopalpus lignosellus), Southwest  corn borer (Diatraea grandiosella), Western corn rootworm (Diabrotica virgifera virgifera), corn leaf aphid (Rhopalosiphum maidis) and corn leafhopper (Dalbulus maidis). Huang et al.(55) have already assessed Cry proteins specificity through essays  in connection with cell vesicles, evidencing the high specificity of this protein complex  to insect receptors.
Efficacy essay was conducted in the cities  of Itumbiara, (GO), Toledo (PR), Indianápolis (MG), and Jardinópolis (SP) during the 2005 calendar  year. Experiments were conducted according to cultural practices recommended  for each region.  In that same year, a first assessment was  made, including incidence of initial pests and predators. Incidence of the lesser cornstalk borer, Elasmopalpus lignoselus (Zeller), was not  recorded in any of the localities. Pooled variance analysis of data in the four localities revealed significant difference among the three treatments studied: conventional Pioneer P30F33 corn with application  of  insecticide, conventional Pioneer P30F33 corn without application  of  insecticide, and the same hybrid P30F33 - 1507 (Bt), using F test. Analysis of data related to assessment of herbivory and incidence  of green stink bug,  based on the percentage  of plants  with damage symptoms, revealed that interaction site x treatment was  significant. The result showing the comparison of averages for herbivory is lower for the P30F33 - TC1507 in each site.
Currently there is an indiscriminate use  of insecticides in Brazil, including a mix of chemical products, in an attempt to control insects, especially S frugiperda. With the massive employment of these chemical products an agricultural desert is created  in certain Brazilian regions,  since  the natural enemies  of  such pests  are  the first to be eliminated. Frequent employment of chemical insecticides  contributes to environmental  degradation, pollution and an environmental breakdown in corn culture  and even in other  rotation  crops. By adopting insect  resistant genetically modified  plants, reduction in insecticides has been considerable in countries  where this technology has been adopted for over  ten year. In the United States, for instance, farmers have obtained reductions of over 8,000 tons of active insecticide ingredient in 2001  alone(52, 53, 54). In China, the employment of insecticides were reduced 67% on average, and reduction in volume of active insecticide ingredient reached 80%(55). In South Africa, the  reduction was  around 66%(56). For the foregoing, one may argue that the use of the Bt  technology in Brazil may contribute towards a reduced employment of insecticides  and, consequently, mitigating the  impacts to the  environment and human and animal health resulting from the use  of these pesticides. Furthermore, the use of Bt technologies may positively affect the preservation of non-target populations and beneficial insects, facilitating an integrated management of farm pests(57, 55, 58). In addition, adoption of technologies that minimize the spraying of chemical products in crops  may bring secondary benefits such as reduced use of inputs in the  production of  pesticides, conservation of fuels used  to produce, distribute and  apply the pesticides and elimination of  the  need for use and  discard of pesticide packing
LMO detection and identification methods proposed
molecular traditional methods
Additional Information
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