Diário da Saúde, 18/10/2011
A conceituada revista Nature apresentou nesta semana um longo artigo ponderando a aprovação do feijão transgênico da Embrapa.
“Junto com o arroz ou misturado na feijoada, o feijão é um componente essencial da culinária brasileira,” começa a reportagem, lembrando que agora o país será pioneiro no uso de um grão fruto da engenharia genética para consumo humano.
“Grupos ambientalistas e o Conselho Nacional de Segurança Alimentar e Nutricional, ligado à presidência da república, pediram mais transparência na biotecnologia e na tomada de decisões, e mais pesquisas para descartar os riscos à saúde derivados do feijão transgênico,” pondera a revista.
Mas essas demandas não foram ouvidas.
Referindo-se à CTNBio, a comissão que aprova os organismos transgênicos no Brasil, a revista afirma que “os membros atuais da comissão defenderam agressivamente sua posição”.
Não existe segurança absoluta
“Os agricultores têm plantado grandes áreas de milho, soja e algodão geneticamente modificados, com pequena resistência por parte do público, mas a Embrapa agora está lidando com um produto que as pessoas comem em grandes quantidades a cada dia,” afirmou Rubens Nodari, da Universidade Federal de Santa Catarina, ouvido pela Nature.
Quem defendeu mais “agressivamente” a aprovação do feijão transgênico foi Edison Paiva, presidente da CTNBio, que afirmou à revista que os opositores à aprovação do alimento humano transgênico estão querendo que os cientistas garantam segurança absoluta, o que seria impossível.
Embora os cientistas não possam garantir que não haverá riscos à população, Francisco Aragão, da Embrapa, afirmou que “as análises de segurança não mostraram razões para preocupações com relação ao feijão [transgênico]”.
Armamento molecular
Aragão afirmou ainda que o feijão geneticamente modificado não produz “proteínas não-familiares”, como acontece com outros grãos transgênicos, e que poderiam causar reações alérgicas quando esses grãos são ingeridos.
O feijão transgênico produz apenas fragmentos de RNA projetados para reagir e neutralizar o RNA dos vírus invasores.
Herve Vanderschuren, biotecnólogo suíço também ouvido pela revista, afirma que as plantas produzem fragmentos de RNA naturalmente para se defender de ataques virais, “e não há evidências de que esse armamento molecular seja perigoso para os humanos”.
“A comissão de biossegurança tem adotado uma posição favorável à biotecnologia nos anos anteriores, ajudando o Brasil a se tornar o segundo maior produtor de cereais geneticamente modificados, atrás dos Estados Unidos,” afirma a Nature.
—
Leia abaixo a matéria original da Nature:
Published online 12 October 2011 | Nature 478, 168 (2011) | doi:10.1038/478168a
News
Brazil cooks up transgenic bean
Approval draws criticism over transparency and safety tests.
Paired with rice or steeped in feijoada stew, beans are an essential feature of Brazilian cuisine. So great is Brazil’s love of legumes that demand often outstrips domestic supply, forcing the country to import beans from Argentina, Bolivia and China. But this relationship could face the ultimate test as Brazilian scientists roll out a transgenic pinto bean (Phaseolus vulgaris) engineered to fend off one of the crop’s most devastating enemies: the golden mosaic virus.
Approved on 15 September by the Brazilian National Technical Commission on Biosafety (CTNBio), the transgenic bean uses RNA interference to shut down replication of the virus (K. Bonfim et al. Mol. Plant Microbe Interact. 20, 717–726; 2007). A product of more than a decade of home-grown research, the bean could begin appearing on tables across the country as early as 2014.
“It is an extremely important crop for our small farmers,” says Francisco Aragão, a plant geneticist who led the work for the Brazilian Agricultural Research Corporation (EMBRAPA), the research arm of the Ministry of Agriculture, based in Brasilia.
The biosafety commission has taken a favourable position towards biotechnology in past years, helping Brazil to become the world’s second-largest producer of genetically modified (GM) crops, behind the United States. Farmers have planted vast tracts of GM maize (corn), soya and cotton with little public resistance, but EMBRAPA is now tinkering with a product that people eat in large quantities every day, says Rubens Nodari, a plant geneticist at the Federal University of Santa Catarina in Florianopolis.
Environmental groups and a presidential advisory panel, the National Council for Food Security and Nutrition, have called for more transparency in biotechnology science and decision-making, and increased research to rule out health risks stemming from the bean. Nodari, a former member of CTNBio who has long questioned transgenic crops, says that the commission improperly granted EMBRAPA’s request for confidentiality regarding key aspects of the genetic engineering. “We don’t know what we will be eating tomorrow in Brazil,” he says.
Current members of the commission have aggressively defended their decision. In a media interview after the decision last month, Edilson Paiva, president of CTNBio, said that Nodari and other opponents of genetic engineering are taking an ideological position aimed at “promoting fear and uncertainty” as they demand that scientists provide the impossible: guarantees of absolute safety.
EMBRAPA says that it must keep core information about genetic insertions confidential, to allow it to patent the work. The details will help the agency to develop bean varieties that are resistant to the golden mosaic and similar viruses, says Aragão, who is a member of CTNBio but abstained from the decision on the beans.
Aragão notes that safety analyses showed no reason for concern regarding the beans. He says that whereas some other GM crops produce unfamiliar proteins that could in theory cause an allergic reaction when eaten, the GM pinto bean produces only small snippets of RNA, tailored to react with and neutralize RNA from any invading virus. Herve Vanderschuren, a biotechnologist at the Swiss Federal Institute of Technology in Zurich, adds that plants naturally produce similar RNA snippets to defend themselves from viral attack, and there is no evidence that this common molecular warfare is dangerous to humans.
With approval secured, EMBRAPA must now conduct a further round of field trials to ensure that the transgenic bean produces yields comparable to those of existing varieties. Aragão hopes that the strain will not only boost yields, but also enable planting on as much as 200,000 hectares of land on which the golden mosaic virus is so prevalent that farmers cannot grow beans at all at present. Brazil produces some 3.5 million tonnes of beans per year already, and Aragão says that the transgenic bean could increase production by 10–20%, enough to offset imports and soften the price spikes that accompany domestic shortages.
“The best part of this story is that the bean was developed in Brazil for the Brazilian farmers,” says Vanderschuren, who is part of a consortium working with researchers in Kenya, Tanzania and South Africa to apply the same technology to local crops, including cassava.
EMBRAPA is already looking to develop other virus-resistant beans, including common black beans and the popular carioca bean. “It’s very easy to transfer this gene to any other variety,” says Aragão. “That’s the next step.”
Comments
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- #27731
This is a perfect example of what the revolution in molecular biology has accomplished, and it uses an existing system to accomplish the goals, it’s not transgenic.
I expect to hear people in the US and Europe claiming it’s untested and unnatural but these claims would be out of ignorance. Safety trials need to be conducted and I expect the virus will change with time – complete eradication isn’t likely but this is a major breakthrough. Great work!
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- 2011-10-12 12:51:19 PM
- Posted by: Charles Hollahan
- #27734
The Brazilian team deserves commendation for this great achievement. Congratulations.
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- 2011-10-12 01:29:10 PM
- Posted by: Abdulrazak Ibrahim
- #27749
Brazilians, with a few, well known, recurrent exceptions, are very proud of the work of the plant geneticists at EMBRAPA.
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- 2011-10-12 09:45:09 PM
- Posted by: Homero Dewes
- #27755
Because small RNA molecules have always been part of our diets does not mean that all small RNAs are safe. Bacteria have always been on our food, but some cause harm. What we already know is that small RNA molecules that cause RNAi have off-target effects. We know that small RNAs transmit through food to animals. Plant miRNA has now been found in the human circulatory system, probably from food. These miRNAs can effect gene silencing in the mouse liver, and in human cells. Novel small RNAs that are created through this process ought to be checked for having unintended adverse effects on people and key insects and wildlife. There is still much more that we don’t know about small RNAs than we do. If the novel small RNAs in the GM bean have been tested, let’s see the data. If not, why not? Thanks to the good scientists of Brazil who have the wisdom to ask for the testing that can, and I think should, be done.
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- 2011-10-13 04:15:57 AM
- Posted by: Jack Heinemann
- #27783
@Jack Heinemann
Could you provide links to some refereed papers that describe the finding of plant miRNAs in humans? I’m particularly interested in the plant origin claim. AFAIK for a miRNA to work it must match the sequence of the target mRNA. So if a miRNA in the blood matches a human mRNA then how do we know it came from a plant and is not just a normal human product?
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- 2011-10-13 04:00:53 PM
- Posted by: David Grant
- #27899
@ David Grant
Zhang et al. 2011 Exogenous plant MIR168a specifically targets mammalian LDLRAP1: evidence of cross-kingdom regulation by microRNA. Cell Res, 1-20.Several lines of evidence support that these are of plant origin, including the nucleotide level modifications that are special to plants. The matches between these miRNAs and mammal genes is sufficient to achieve the silencing in mice in vivo.
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- 2011-10-15 06:40:47 PM
- Posted by: Jack Heinemann
Nature publica nota de reparo a sua entrevista:
Nature | Correspondence
Agriculture: Risk assessment for Brazil’s GM bean
- Nature 479, 299 (17 November 2011)
- doi:10.1038/479299e
- Published online | 16 November 2011
Your report on the production of genetically modified (GM) beans in Brazil implies that I am an opponent of genetic engineering (Nature 478, 168, 2011). However, you misrepresent my scientific and professional record.
I have never said or written anything against transgenic crops per se. Neither have I claimed to be an opponent of the transgenic technique. However, I have always insisted, as a former member of the Brazilian National Technical Commission on Biosafety (CTNBio) and in my capacity in other professional positions, on critical risk-assessment studies and on research meeting a minimum standard of scientific quality.