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Date:

May 13, 2008

Subject:

GM potato trial OK'd; Uganda gets biotech centre; Green revolutionary returns

 

* Go-ahead for GM potato trial
* Vertical growth in biotech crops
* India's green revolutionary is back
* Uganda sets up cassava biotech centre
* Advances made in crop technology
* GM crops 'would net $8.5b for farmers'
* The world needs GM food now
* EU Biotech Policy and German Ag-Industry
* Biotechnology must become plat principal
* Gene-Based Plant Immunity and a Fungal Effector

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University given go-ahead for open field trial of GM potato crop

- Chris Benfield, Yorkshire Post, May 10, 2008

http://www.yorkshirepost.co.uk/news/University-given-goahead-for-open.4070514.jp

LEEDS University has been given the go-ahead to grow genetically modified potatoes in an open field.

The potatoes have had their genes tweaked by Professor Howard Atkinson to give them resistance to a parasite. Now seedlings are on standby in glasshouses on the university's experimental farm in Tadcaster and 400 will be moved outdoors later this month.

The move was announced yesterday by the Department of Environment, Farming and Rural Affairs (Defra), headed by Leeds MP Hilary Benn.

Some other EU countries already grow GM crops commercially - particularly rape, beet and maize - but development of the GM business in this country has been held back by fear of vandalism by opponents.

The Leeds trial centres on potatoes resistant to the parasite commonly known as "eel worm".

Prof Atkinson said: "This is a university. We don't think it is appropriate to take extreme security measures but also we do not think it is appropriate for people to stop academic research. We have promised to behave responsibly and we hope we will be left to do it."

The potatoes will be used for laboratory purposes only and the soil they are grown in will be sterilised after the harvest.

The NFU has no objections. Its Driffield-based vice president, Paul Temple, has taken part in field trials of GM crops and he says most members are relaxed about them. He said: "We are importing thousands of tons of GM material every day, from other countries in Europe, and we want to see the trials take place and see what happens."

But Pete Riley, of campaign group GM Freeze, said: "This approval is unwise and unnecessary. We are very concerned that Defra persists in approving applications which contain antibiotic-resistant marker genes involving antibiotics which are still in clinical use. These genes are not needed and should be removed. All in all, it's a bad decision by Defra."

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Tremendous scope for vertical growth in biotech crops

'Bt cotton has enabled India turn exporter of the crop'

- G. Chandrashekhar, Business Daily (The Hindu), May 9, 2008

http://www.thehindubusinessline.com/2008/05/09/stories/2008050951921100.htm

Mumbai - With trials of India's first genetically modified (GM) food crop, Bt. Brinjal (insect-tolerant vegetable), progressing well, the anti-biotechnology lobby seems to have become active. Those opposed to biotechnology in agriculture are spreading disinformation, according to Dr Usha B. Zehr, Joint Director of Research with Maharashtra Hybrid Seeds Company Ltd (MAHYCO), pioneer in the country's foray into agbiotech.

Indeed, Bt Brinjal is not the first GM vegetable crop. Globally, as many as 23 vegetable crop species (excluding potato and sweet corn) have been genetically engineered. China grows tomato, papaya, petunia and sweet pepper, while the US grows squash (a variety of gourd) and papaya.

Currently, over a dozen biotech crops are being field-tested in different parts of the world. These include three major staples (rice, maize and wheat) as also potato, tomato, soyabean, cabbage, peanut, melon, papaya, sweet pepper, chilli and rapeseed.

China's agbiotech

Talking about China's advances into agbiotech, Dr Zehr said the country has planted about one quarter of a million Bt. Poplars and in 2006, started to commercialise an approved virus-resistant biotech papaya (a fruit/food crop) developed by a Chinese university and grown on approximately 3,500 hectares.

A virus-resistant sweet pepper and delayed ripening tomato have also been approved for commercialisation, she pointed out. China is the world's largest producer and consumer of rice (over 125 million tonnes a year) and has the world's largest biotech rice programme.

There are an estimated 110 million rice households in China farming an average of 0.27 hectares of rice each. China's biotech rice is resistant to specific pests (insect borers) and diseases (bacterial blight) and is awaiting approval after extensive field trials, the scientist asserted, adding evidence suggests that the biotech crop reduces insecticide application by 80 per cent or 17 kilograms per hectare. India situation

Interestingly, India is the world's second largest rice producer (after China) with output of about 94 million tonnes. Planted in about 45 million hectares, paddy yields are on an average 3.5 tonnes a hectare, equivalent to roughly 2 tonnes of milled rice. China's paddy yields are far superior at about 6 tonnes a hectare or over 3.6 tonnes.

Cultivation of rice in smallholdings is common to both the countries. If India has to remain self-sufficient in rice, yields have to be raised. There is tremendous scope and need for vertical growth.

According to Dr Zehr, last year (2007 was the 12th year of biotech farming), 120 million farmers in 23 countries grew biotech crops on 114.3 million hectares.

Cotton experience

India's experience with Bt. Cotton has been positive. Cotton output has gone up from about 17 million bales in 2001 to over 30 million bales in 2007. As a result, India has turned into a cotton exporter. Bt. Cotton is now grown in over half the planted area of about 9 million hectares. That should provide sufficient motivation and support to accelerate infusion of more biotech products, especially at a time when a food crisis looms large, Dr Zehr said.

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India's green revolutionary is back in spotlight

- Mayank Bhardwaj and Jonathan Leff, Dawn (India), May 13, 2008

http://www.dawn.com/2008/05/13/int13.htm

NEW DELHI: Forty years after he helped rescue the world from growing famine and a deepening gloom over the future of food supplies, Monkombu Sambasivan Swaminathan is once again agitating for revolution this time a perpetual one.

The 82-year-old scientist, dubbed here the father of the Green Revolution for helping development a hybrid wheat seed that allowed Indian farmers to dramatically increase yields, says the current food crisis offers the world a chance to put farmers on the right road to unending growth.

In the 21st Century's "Evergreen Revolution", as he calls it, conservation farming and green technology will bring about sustainable change that could allow India to become an even bigger supplier of food to the world.

"I'm very happy now, because in every crisis is an opportunity," he said at his government apartment in the heart of New Delhi, a perk of his membership in India's upper house. "This time it will lead to an evergreen revolution."

That would be welcome news for the millions of impoverished people and food-importing nations who are struggling to cope with the surge in basic crop prices over the last year, caused in part by protectionist trade bans by some exporters, including India.This year's near trebling in the price of rice the main staple for most of the world's poor has driven the issue home. It has triggered riots in Haiti and raised the risk of starvation for the hundreds of millions who depend on subsidised foods.

With anxiety over food supply running higher than anytime since the 1960s, the former Cambridge scholar is busier than ever, just as passionate and in high demand.

"My wife says I have a one-track mind," he said during an interview squeezed between a meeting with an analyst from Asian brokerage CLSA and a consultation with a pack of regional politicians.

His wife Mina, a women's rights campaigner who met Swaminathan in Cambridge over 50 years ago, enforces quiet time during his daily siesta, part of a regime that helps give him the energy and focus of a man several decades his junior. A slight stoop and white hair are rare signs of his advanced age.

TAKING CUES FROM 1960S: Today's crisis is still far from that of the 1960s, when China was engulfed in deadly famine and India barely got by on hand-to-mouth imports, reviving the grim Malthusian view that the world's population was expanding too quickly to feed itself.

Back then, Swaminathan, a young scientist who turned down plumb positions in academia and the government to work in agriculture research, helped cross-breed wheat seeds that allowed India to more than treble its annual crop in just 15 years.

US production has risen only about a third since then.

Scientists in the Philippines had also developed a super strain of rice at the same time, and better irrigation and use of fertiliser helped pull India back from the brink of famine.

But Swaminathan says that some seeds of the current crisis were sown in his own revolutionary heyday.

"The Green Revolution created a sense of euphoria that we have solved our production problem. Now we have a plateau in production and productivity. We have a problem of under investment in rural infrastructure," he says.

With genetically advanced seeds, farmers overlooked the potential ecological damage of heavy fertiliser use, the drop in water tables due to heavier irrigation and the impact of repeated crop cycles on soil quality.

He believes we've learned from those lessons, and the next wave of improvements will have environmental considerations at their core, without the need to return to the genetics lab.

"A short-term gain will have to be a long-term disaster in agriculture," says Swaminathan, who held a series of leadership roles in world agriculture organisations before establishing his non-profit Chennai-based M.S. Swaminathan Research Foundation 20 years ago to promote farm growth that will aid the poor, particularly women, and bio-diversity.

COURSE MEAL: But not all his ideas are popular.

Some abroad are unimpressed by his focus on India's self-sufficiency as the primary goal, and those at home question the cultivation of more easily grown foods such as courser grains rather than finer, more costly wheat or rice.

"Would you eat them?" India's food secretary T. Nand Kumar asked earlier this week.

Not that Swaminathan has given up on the staples.

In a world threatened by rising temperatures, he says India should grow more rice rather than wheat, the latter of which India was forced to import over the past two years.

"Wheat is a gamble in temperatures... Rice is going to be the saviour crop in the era of climate change," he said.

With a host of measures suggested to kickstart the struggling sector, Swaminathan believes farmers should be allowed to play a pivotal role in leading the change, though he regrets it took a crisis to finally shift the world's attention back to the land.

"Only when disasters come, farmers become important."

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Uganda sets up biotechnology centre to study cassava

- Africa Science News Service, 10 May 2008

http://africasciencenews.org/asns/index.php?option=com_content&task=view&id=373&Itemid=2

Uganda's scientists have set up a biotechnology centre at the National Crops Resource Research Institute (NCRRI) for purposes of modifying cassava.

The scientists with the help of the Association for Strengthening Agricultural Research in Eastern and Central Africa (Asareca), launched its cassava biotech capacity project through its Agro-biodiversity and Biotechnology programme at the National Crops Resources Research Institute (NCCRI) on April 30, 2008.

Dr Charles Mugoya, a senior scientist, Asareca, said the $110,000 project fund is part of the $320,000 about that was shared among three countries of Kenya, Tanzania and Uganda.

Dr Anton Bua, an Agric-Economist and Team Leader for National Cassava Programme, said Uganda did not have facilities to undertake advanced science like biotechnology which is a world order. "Because of Asareca's support, we will now build capacity to perform very high and advanced science which we normally borrow from Europe and America," said Dr Bua.

Ugandan researchers are working to follow in the footsteps of researchers at the Donald Danforh Plant Science Centre (DDPSC) in the United States.

DDPSC introduced a genetically modified gene in a cassava plant to confer resistance to Cassava Mosaic Disease (CMD), which research results proved successful.

This research has been carried out in several countries in Africa of which Uganda is now involved.

Cassava's ability to produce food under marginal conditions has made it a popular crop among Africa's poor.

According to scientists, cassava is the most consumed crop in East and Central Africa with over 30 million tons of it being produced annually.

On average, the value of cassava production between 1961 and 1999 in Uganda amounted to$2 billion.

The record indicates that Uganda is the third largest producer of cassava in the Asareca, with a total production of 5 million metric tons per year.

But cassava mosaic, a viral disease and other pests have reduced Uganda's cassava production.

According to the scientists, cassava mosaic and cassava brown streak disease are the most important constraints affecting cassava production in Uganda and most parts of African countries.

Other viruses include Africa Cassava Mosaic Virus (ACMV) and the East African Cassava Mosaic Virus (ECMV) which is transmitted by a pest called Whitefly Bemicia Tabaci.

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Advances made in crop technology

- Wendy Davis, Times Republic (Illinois, USA), May 8, 2008

http://www.timesrepublic.info:80/articles/2008/05/08/local_news/288news02.txt

The advancement in the study of crop technology has come a long way.

Mike Hellmer, technical services manager with Pioneer, spoke at the extension office's ag breakfast yesterday.

In his "Technology Pipeline" presentation he gave examples of what a better understanding of the seed's genetics has done.

He explained how double haploids give better and quicker results than customary inbreeding.

With double haploid studies, scientists are interested in using only the female chromosomes of the plant. They will take these chromosomes, add a chemical and it duplicate them.

"Usually only about 10 kernels on that ear you can use," she said.

With this technology it takes two generations to results rather than seven with inbreeding.

Other genetic advancements include gene shuffling.

"This is some great technology", said Hellmer. "You find a segment of DNA which does some interesting stuff but doesn't do it at the levels needed. The DNA can be split apart and be put back together."

Also marker assisted selection marks a segment of DNA to be moved to another plant. This way it can be seen when it is moved to the new plant.

"Now it can be done in a process that leaves no doubt," said Hellmer."Scientists today are getting so good at looking at genes," he said.

He said corn used in developing other crop technologies can now mature in 45-60 days to evaluate other plants quicker.

With soybeans scientists have found the genes to control yield.

"There are eight different segments in soybean," he said. "We want to make sure all segments come into our new varieties.

There is also an expanded weed control option. He said, today, farmers are using glyphosate is used. In the future, "we'll use it with ALS."

Scientists have also been working on anthracnose stalk rot resistance and drought tolerant corn.

Stalk rot resistant corn was found in South American but it previously could not work with corn grown in the United States. When the technology was available, he said, that segment of DNA was cloned and put into U.S. corn.

"Currently, we're evaluating 24 hybrids with this anthracnose resistant gene," he said.

As for drought tolerance, it is more difficult.

"There are a lot of unknowns in drought tolerance," said Hellmer. "We can produce a lot more bushels in drought stressed corn than we could in the 20-50s," he said.

Today, managed stress environments can simulate conditions. The best places to use these environments are California and Chili, where there is virtually no rainfall from May to September.

Using drip tape, they practice precision irrigation.

"It's such a good science. We can now completely control the stress of the genes," he said.

More and more is learned everyday, he said.

"When kids are looking for direction in a career, we are struggling to find students with a PhD background to help in the ag sector. They don't need an ag background," he said.

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GM crops 'would net $8.5b for farmers'

- The West Australian, May 12, 2008

http://www.thewest.com.au/aapstory.aspx?StoryName=481672

Open-slather planting of genetically modified (GM) crops would net Australia $8.5 billion during the next decade, government researchers estimate.

According to a report by the Australian Bureau of Agricultural and Resource Economics (ABARE), GM crops would boost yields, cut costs, help the environment and boost biodiversity.

But the Australian Greens have rejected the $8.5 billion figure and warned that introducing the controversial crops would do more harm than good.

Most GM crops are banned in Australia but farmers can plant GM cotton and NSW and Victoria have allowed GM canola from this year. State governments decide what can be sown.

According to the Economic Impacts of GM Crops in Australia report, if all GM crops were allowed now, the Australian economy would benefit by $8.5 billion by 2018.

NSW would benefit the most, by $3.5 billion, followed by Western Australia on $2.4 billion.

Delaying the introduction of GM canola by five years would lead to "foregone benefits" of $97 million in WA and $66 million in South Australia, the report said.

ABARE's executive director Phillip Glyde said the report showed that maintaining the bans on GM crops would cost farmers dearly.

"Delaying GM uptake means we are foregoing significant economic benefits for regional Australia," he said.

GM crops were more resistant to pests and weeds, meaning fewer chemicals had to be used, which increased yields. Labour, machinery and fuel costs also fell with GM crops, the report said.

"Managing GM crop production is generally easier and less time-consuming than non-GM crop production," the report says.

GM canola and soy beans had strong potential for Australia and wheat and rice could work down the track, it said, although maize was of uncertain economic benefit.

The report found GM crops were good news for the environment because there was less crop spraying, which meant cleaner soil and water and more beneficial insect species.

But Greens senator Rachel Siewert said ABARE had been pro-GM "from the start" and the report lacked credibility.

"It's grossly exaggerated, I question their figures, I question their objectiveness," Senator Siewert said.

"It's a very biased view."

She said ABARE used figures provided by industry without independently analysing them.

She said the report had downplayed the costs and potential problems associated with using GM crops. For example, growing them could exclude Australia from some lucrative markets in Europe and Japan.

Senator Siewert said GM crops were unproven and there were health concerns about introducing them into the food chain.

The Greens were also worried about the crops contaminating non-GM areas. And they may need more chemicals in the long-term than other crops, she warned.

"I think there needs to be a lot more independent research done on the costs and benefits," Senator Siewert said.

The ABARE report was funded by the federal Department of Agriculture, Fisheries and Forestry.

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If ever the world needed GM food production, it's right now

- Kevin Myers, Independent.ie, Apr. 23, 2008

http://www.independent.ie/opinion/columnists/kevin-myers/if-ever-the-world-needed-gm-food-production-its-right-now-1355873.html

The dilemma is simple. The sustained hysteria over global warming is finally beginning to cost lives -- as it was bound to. Ignoring the laws of nature -- and the market place is nature at its purest -- will always exact a price. And the price is usually paid by the weakest and the most vulnerable in a society: of course, this will not include -- and never could include -- the well-heeled humbugs who have driven the hysteria in the first place.

We were told that one way of tackling global warming was to burn biofuels rather than fossil fuels: since replacement crops will absorb the carbon dioxide created when the biofuels combust, the transaction is said to be "carbon neutral".

Governments have thus been rewarding producers for growing biofuels -- with the result that in the US, many farmers prefer to grow them rather than food. Listen: I was the worst student ever to pass first-year economics at UCD, but I still understand the consequences of cutting supply. Prices go up.

And that's what's happened. Rice is roughly twice the price that it was a year ago. That's irritating for us, but perfectly catastrophic for the poor of the world. So serious is the problem that India (among many other countries) has outlawed the export of rice: a further interference in the market. And that's the way of such things: one correction obliges the market-molester to endlessly correct as the initial distortion caused by the first correction begins to rock the entire structure.

No-one can manage the consequences, because they are too complex and unpredictable.

Now, you might argue that increasing the price of food is a necessary, if tragic, step towards saving the world from global warming. But it is a strange morality indeed which also campaigns against a technology that could both make food cheaper, and biofuels easier to grow.

Yet the science of genetic modification can unleash the vast untapped resources which are locked up in the DNAs of different species.

As Swift so aptly put it: "that whoever could make two ears of corn or two blades of grass to grow upon a spot of ground where only one grew before, would deserve better of mankind and do more essential service to his country, than the whole race of politicians put together".

Quite. Yet it is the political classes in Europe, with the eco-mob at their heels -- they who wax so hysterical about global warming -- who have prevented the development of GM products here. Supermarkets even boast "We sell no GM products", as witless as the 19th-century apothecary's response to Edward Jenner's discoveries: "No vaccination here".

Simply, GM will enable us to increase plant production, without greater use of fertiliser, for three purposes: to grow biofuels, to produce greater vegetable crops, and, finally, to cultivate special plants whose sole duty is carbon imprisonment. This last function is what the molluscs of the oceans did millions of years ago. By locking up atmospheric carbon in their tiny shells, in due course they became the great limestone, marble and chalk mountains of the world, thereby lowering the world's temperature, and making terrestrial life possible.

But the very people who grew hysterical at the prospect of GM crops five years ago are today at the forefront of shrieking about global warming. The mathematics of all this are quite simple. So too are the morals. What is less easy to understand is the philosophy which prevents us from the reaching the logical conclusion to which maths and morals direct us.

For if we are to move towards biofuels, either we have GM technology, or millions of people in the developing world (as it is incorrectly called, because a lot of it isn't developing at all) will die. There is no third way.

Now, you can argue that the world could do with a reduction of population, and since there is no obvious group rather altruistically volunteering for extinction, the winnowing out of unwanted bodies will have to occur naturally somewhere that the population is already growing faster than are local resources.

There is a name for such a place. It is Africa. Is this what people want? That Africans should die of hunger in their millions, in order that we should feel better because we are using carbon-neutral biofuels, even as we are outlawing the GM technology that will make those fuels, and foodstuffs, cheaper and more available?

It is an interesting morality which embraces this equation, especially since the mumbo-jumbo over global warming is usually propounded by people who declare themselves to be morally superior to just about everyone else on the planet.

You may just have gathered from my tone my position on this. It is that mankind can do almost nothing useful to lower global warming, and therefore we shouldn't try. But sideline that argument, and address the hypothetical possibilities of reducing CO2 levels by plant activity, without causing famine. That cannot be done without GM: moreover, changing the genes of plant life is what mankind has done ever since the invention of agriculture, in the alluvial gardens of Mesopotamia 10,000 years ago.

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Germany: Discussion Paper of German Ag-Industry about EU Biotech Policy Implications

- US Department of Agriculture, Foreign Agricultural Service, May 12, 2008

http://www.fas.usda.gov/scripts/gd.asp?ID=146294560

A group of German food and feed industry associations released a discussion paper expressing the industries' concerns about the negative implications of the EU biotech policy. The industry is highly concerned that the EU policy on biotechnology will cause significant supply problems for Germany. The concern is heightened by the prospect of new biotech events, such as the second generation RR soybeans, being introduced in the U.S. and other major soybean producing countries. The EU biotech policy prohibits the importation of food/feed products containing traces of not yet EU-approved biotech events.

View the Acrobat version: http://www.fas.usda.gov/gainfiles/200805/146294560.pdf

View/Download the MS Word version: http://www.fas.usda.gov/gainfiles/200805/146294560.doc

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Biotechnology must become plat principal

A chat over breakfast hardly matches the urgent needs of a hungry world.

- European Voice, May 8, 2008

http://www.europeanvoice.com/article/imported/biotechnology-must-become-plat-principal/60680.aspx

The European Commission's breakfast review of Europe's biotechnology regulation yesterday (7 May) scarcely did justice to the subject. Instead, it provided a further compelling illustration of why the European Union still so frequently disappoints rather than dazzles.

That this long-awaited review was relegated to a breakfast might be justified on purely administrative grounds, as a mechanism for bringing all the Commissioners together to focus on a single subject. But for a subject that the Commission itself recognises to be of importance, it nonetheless creates the impression of a marginal and brief encounter: coffee and croissants hardly suggests sharp focus and sustained attention.

If the "orientation debate" - as the Commission terms it - looked like it was too little, it also certainly came too late. The EU rules on approval of biotechnology products date back nearly twenty years and despite repeated modifications and additions, the authorisation process is a mess. The Commission claims that the EU has the world's strictest system for approval of biotechnology products. Strict it may be. Efficient it definitely is not.

For years now, EU member states have failed to agree on dozens of applications for authorisation of genetically modified (GM) products. Some member states have entertained profound doubts about the safety of GM maize or soya or potatoes. Others have championed the innovations. The result has been deadlock. As the Commission drily observed after its orientation debate, "one must note that the member states in the Council [of Ministers] have persistent difficulties to reach decisions on the matter".

But the system is so ineffective that these decisions come back in the end to the Commission, which has, on more than a dozen occasions over the last few years, granted authorisations. In consequence, member states that opposed the release of these products have responded by erecting their own barriers, invoking safeguard clauses and other devices to prevent the products reaching their market.

Irrespective of the merits or demerits of biotechnology, the situation makes the EU look ridiculous. For all the sophistry that is deployed to defend the system as a judicious balance between safety, consumer choice and protection of biodiversity, it manifestly does not work.

The problem is more than an internal squabble affecting the EU's credibility. Europe's attitudes to biotechnology have resonances and create turbulences way beyond its shores. The consequences lead to trade disputes and to administrative burdens for importers. The EU has repeatedly been attacked for imposing undue restrictions on international trade. And the EU's requirements for rigorous separation of GM and non-GM food and feed generates shipping delays and costs.

The recent spike in world food prices and intensifying food scarcity have added a further dimension to the dispute.

Raising agricultural yields, which is one of the leading advantages claimed by the proponents of biotech, has obvious major potential as a contribution towards a solution.

But at present, the lack of decisiveness in Brussels is handicapping exploration of these avenues - both within Europe and beyond. There is little incentive for an exporting country even to test new technologies if the price will be exclusion from the lucrative EU market.

As the Commission also remarked after its orientation debate, "this is a highly complex matter". No one would deny that. The divisions within the Commission itself testify to the complexity. But complexity is no excuse for the EU as a whole taking so long to grapple with the issues and to establish both clearer thinking and faster processing. The Commission has made a start with its breakfast. It is to be hoped that the EU as a whole is not to make too much of a meal of reaching some real solutions.

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Suppression of Plant Resistance Gene-Based Immunity by a Fungal Effector

- Petra M. Houterman, Ben J. C. Cornelissen and Martijn Rep, PLoS Pathogens, May 9, 2008

http://www.plospathogens.org/article/fetchArticle.action?articleURI=info:doi/10.1371/journal.ppat.1000061

Abstract

The innate immune system of plants consists of two layers. The first layer, called basal resistance, governs recognition of conserved microbial molecules and fends off most attempted invasions. The second layer is based on Resistance (R) genes that mediate recognition of effectors, proteins secreted by pathogens to suppress or evade basal resistance. Here, we show that a plant-pathogenic fungus secretes an effector that can both trigger and suppress R gene-based immunity. This effector, Avr1, is secreted by the xylem-invading fungus Fusarium oxysporum f.sp. lycopersici (Fol) and triggers disease resistance when the host plant, tomato, carries a matching R gene (I or I-1). At the same time, Avr1 suppresses the protective effect of two other R genes, I-2 and I-3. Based on these observations, we tentatively reconstruct the evolutionary arms race that has taken place between tomato R genes and effectors of Fol. This molecular analysis has revealed a hitherto unpredicted strategy for durable disease control based on resistance gene combinations.

Author Summary

In agriculture, the most environmentally friendly way to combat plant diseases is to make use of the innate immune system of plants, for instance by crossing into crop varieties polymorphic resistance genes that occur in natural populations of the crop plant or its close relatives. Plant pathogens, however, have co-evolved with their host plants and have developed ways to overcome the immune system. To effectively make use of components of the plant immune system, it is therefore important to understand the co-evolution of plants and their pathogens at the molecular level. For the interaction between a fungal pathogen and tomato, this paper presents a breakthrough in this respect. A small protein secreted by some strains of the fungus Fusarium oxysporum was found to suppress the activity of two disease resistance genes of tomato. However, a third resistance gene specifically targets this suppressor protein and renders the plant fully resistant against fungal strains that produce it. With this insight, together with knowledge of the genetic variation in the pathogen population, a combination of resistance genes is suggested that is expected to confer durable resistance in tomato against Fusarium wilt disease.

[click on link above for full article]

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*by Andrew Apel, guest editor, andrewapel*at*wildblue.net