“This biotech research and development center, located near life sciences hub Wageningen University in the central Netherlands, may have more influence on the future of what we eat and how it tastes than any other agricultural program in the world.”
Europe’s first serious plant “breeders” were the Cistercian monks, who kept the remnants of Roman agriculture alive throughout the Middle Ages. But the monks were limited to selecting from accidental crosses produced by nature. As a result, conservation and chance improvement of prized, ancient fruits were really more acts of faith and deliberation. Renaissance trade and curiosity began to open the palate, but the scientific origins of fruit breeding and selection awaited the turn of the 19th century, when Thomas Andrew Knight of London’s Royal Horticultural Society began systematic breeding programs aimed at producing superior fruits and vegetables.
Two centuries later, European scientists remain at the forefront of fruit and vegetable engineering. Plant geneticists in Holland’s so-called “Food Valley” today are using genomic mapping to analyze and transform classical plant breeding techniques. This biotech research and development center, located near life sciences hub Wageningen University in the central Netherlands, may have more influence on the future of what we eat and how it tastes than any other agricultural program in the world.
But to do so, the scientists working there will have to overcome near fanatical resistance to genetic engineering and national as well as European Union laws that ban most genetic engineering of fresh fruits and vegetables—not to mention brigades of anti-GM activists in Germany, France, and England who readily destroy open research fields. The stakes are enormous because they concern the world’s major fresh foods: tomatoes (the world’s largest fresh commodity), apples (the world’s most ubiquitous fruit), lettuce, peppers, and potatoes—all of which are facing pesticide bans and greater disease threats than ever in history. If they succeed, the plant engineers could end up saving the global agriculture industry tens of billions in annual losses that result from spoilage and crop failures. What’s more, they stand to reduce greenhouse gas emissions created from pesticide and fertilizer manufacture.
Confronted, however, with the reality of anti-GM sentiment in Europe, scientists at two “Food Valley” companies, Genetwister and Keygene, have developed different but equally innovative strategies. Genetwister focuses on genetic analysis of the “keeping qualities” (the length of survival in transit and on the shelf) of fruits and vegetables for some of the world’s largest produce brokers. Because this technique tracks how certain genes are expressed, it is called “expression profiling.”
Keygene uses finely tuned gene sequencing to identify the most promising “parents” for conventional breeding, and then to eliminate all but the best progeny well before those progeny push out their first blossoms or bear their first fruit. This saves breeders thousands of hours of labor and reduces by as much as two-thirds the amount of time it takes to come up with new varieties. If you’re a tomato seed company working the most cutthroat market in the vegetable world, those two advantages can spell life or death. The same is true in the market for cucumbers, peppers, or potatoes.
“We are living in an agricultural food world rocked by change,” Keygene CEO Arjen van Tunen told the Continent’s biotech leaders at last year’s annual Euro-Bio conference in Lille in September. He went on to explain that tomato breeders compete to create new varieties so rapidly that the market lifespan of each new tomato is only five years. Seed companies—and growers—that fail to meet ever tougher demands for better taste and longer shelf life are soon out of business. All of which puts enormous pressure on the biotech labs.
Keygene’s leg-up in the hot tomato race began more than 15 years ago when it developed a DNA fingerprinting technique called AFLP (Amplified Fragment Length Polymorphism) that enables it to identify a specific strand of genetic pairs in a chromosome. Wageningen-based Keygene, which was founded by a consortium of the world’s leading seed companies inside and outside of Holland, licensed the AFLP technology to a wide array of labs—and it’s most famously used now in crime scene analysis to identify criminals’ genetic material. Royalties from AFLP licenses still pay for a good deal of the lab time Keygene’s researchers spend crossing thousands of wild tomatoes with older varieties.
Each cross, undertaken by conventional means, may include as many as 3,000 plants. A typical breeder would have to allow all of those plants to mature and bear fruit, then present those fruit to a tasting panel to select the best. But by using AFLP analysis, researchers can quickly identify not only which plants lack sufficient disease resistance, but also which will have other undesirable qualities—low productivity, short shelf life, small size, etc.—when the plants are no more than tiny seedlings in a plastic cup sustained by growth hormone. On average, well over 95 of them can be immediately eliminated and the rest then back-crossed to arrive at the most promising new varieties.
Two of the best known tomatoes now on the European market, Tasty Toms and Tiger Tomato, developed with Keygene technology, have won rave reviews for tangy sweetness combined with a two-week shelf life. Tigers are a largish cherry tomato size with gold stripes on a red-to-magenta ground while Tasty Toms are full red, medium sized, and grow in grape-like clusters. Keygene’s Van Tunen emphasizes that the breeding “technology” used for both was molecular but not transgenic. Molecular, genetic markers were used to enhance the crosses that produced seeds for each tomato.
Most of the commercial lettuce cultivated in California depends on Keygene technology, focused on breeding resistance to aphids that, in conventional lettuces, can destroy an entire season’s produce.
Critical to Keygene’s successes with fast breeding cycles are the extraordinary software advances that enable bio-technicians to run gene scans. “It cost us $25 per [genetic] base pair to sequence the DNA in 1990,” van Tunen explains, and today it costs $0.00005 per base pair.” Or, as he says, while walking through Keygene’s lab quarters in Wageningen, “a few years ago we could sequence 100,000 base pairs per technician per day. Now we have a machine that can sequence 1 billion per day.”
A block away, Genetwister’s scientists develop genetic assays of fruit- and vegetable-keeping qualities. Genetwister co-founder Douwe de Boer explains, for example, that an apple’s crunchiness depends on a group of apple genes called ETRs, or Ethylene Receptor genes, the ones that Genetwister tracks through “expression profiling.”
“These are what we call texture genes,” de Boer says. Texture, because this array of genes governs the firmness, durability, and elasticity of the cellular walls within a fruit or vegetable. As apples and other fruits ripen and mature, they give off ethylene gas, which advances maturity into decay. Put some apples in your fridge in a bag with lettuce and celery and you’ll see how quickly the green leaves turn yellow from the effects of ethylene. Some ethylene receptors absorb the gas more quickly than others, contributing to cell wall softening, which is why some apples lose their crunch faster than others.
De Boer says the company only sequences the genes that are active at a certain time period. For example, in fruits, only a subset of a plant’s 20,000 or 30,000 genes is present in the actual fruits. And only a subset of this subset is active during ripening. “We determine which genes are involved in the ripening process and which genes are involved in ‘disorder development,’ which can lead to damaged tissue prone to infection by pathogens, which leads to rot,” he says. Even if the particular genetic profile may prevent outright decay for months, it can still leave the fruit unpleasantly soft.
The solution to disorder development, as well as problems of disease resistance, appears to follow the same principle that first overcame tuberculosis in the late 1940s and that immune researchers have applied to AIDS: attack the disease from multiple directions at the same time. Instead of fighting viral, fungal, or bacterial diseases by seeking out single protective genes, they aim to implant multiple resistance genes that will prevent disease from developing, just as humans are often treated with multiple antibiotics. The key example is scab, a fungal infection that can strip an apple tree of its leaves. Trees bred 25 years ago to resist scab with a single gene are already getting sick as the fungus has evolved and overcome the single gene protection.
Tracking genomic markers, as Keygene and Genetwister do, can speed up testing for disease resistance, but it still takes upwards of six years in field trials, and even then the trees are too young to bear fruit, which is the final test of an apple’s worth. At Wageningen’s Plant Research Institute, senior researcher Henk Schouten plucks out genes resistant to scab from wild apple varieties and inserts them directly into older cultivars. “This,” Schouten says, “is what we call Cis-genesis.”
“We now have a treasure box with increasing number of genes available just for Cis-genesis. We introduce just these wanted genes into our new apple cultivars—or in existing high-quality cultivars—without any unwanted genes, just making them directly resistant to scab.”
The same techniques can be used to alter other characteristics, such as color. Schouten mentions a specific gene called MYB 10 that was first identified by New Zealand researchers. The MYB 10 gene, he says, produces red leaves, roots, and flowers. “We’d like to have this gene in our well-tasting apples for two reasons: the level of coloration is higher, and it’s very health-promoting because it has an antioxidant capacity,” he says. He adds that if just the skin is red, there are smaller quantities of antioxidants, or what are generally known as a flavenoids. But if the whole apple is red, the antioxidant capacity will drastically increase. There’s another reason for having apples that are red to the core. “It also doesn’t brown as quickly when you slice it.”
At the moment, none of these apples is on the market, nor are there even any trees growing in test fields. Technically, they are seen as “transgenic” because current regulations make no distinction between “cisgenic” and “transgenic” plants: both have been “genetically engineered.”
The Dutch, led by the team at the Plant Research Institute, have petitioned the European Commission in Brussels to distinguish between the two since most of the opposition to genetic engineering is the mixing of species or incorporating certain viral proteins into plants. They argue that chemically and botanically, there is no difference between the hybrid produced through classical Mendelian crossing and through intra-species gene shifting. But diehards like France’s militant José Bové, who go around destroying European research plots, are unlikely to be persuaded.
All of this plant biotech is about much more than finding a prettier fruit that doesn’t brown when you slice it. Ton den Nijs, manager of the University’s plant breeding lab, says society has an important choice to make. It can continue to spray for scab for another 50 years. Or, he says, it can embrace the development of resistance genes that could safely eliminate the need for pesticides. “People say in case of trans-genesis you are introducing novel genes,” says den Nijs. “In case of cis-genics, we do not. We only use genes that are already in apple plants.”
Beyond pesticide reduction, there are still larger issues at stake, a point raised by Keygene’s van Tunen. The lengthening of the global food supply chain is posing ever greater challenges, he says, noting that there are now some 50 cities in Asia that each has more than 10 million people. “Remember that in those cities you have to transport all the vegetables and fruits into the city and that can take a long time, from production site to city,” says van Tunen. “That’s where shelf life and disease resistance gets more and more important.”
The big staple crops—wheat, corn, and soy—are also at risk as many are produced in Europe, the United States, and Brazil and must be shipped to Asia and Africa. “You know, it’s not only fruit that has to prevail a long time,” van Tunen says. “It’s also protecting grains against fungal rot.” After it is cut, lettuce will have to be better shielded from the ravages of oxidation on the edges of the leaves. “All of these kinds of things will be more important in the future,” says van Tunen.
The Dutch are far from the only researchers working on genetic enhancement of the world’s fruit and vegetables. Serious work is underway in Britain, Germany, New Zealand, and of course in the U.S., where Cornell University has long been a global leader. Plant pathologist Herb Aldwinckle has used genetic engineering to improve apple disease resistance for more than 20 years, as has Phil Forsline, curator of America’s largest apple germplasm repository in Geneva, New York, a collaboration between the U.S. Department of Agriculture and Cornell. Forsline is also the research director of the USDA Plant Genetic Resources Unit in Geneva. The Dutch, he says are “right at the top of the field in Europe and throughout the world. They’re at the cutting edge of developmental genetics in apples. They’re the highest per capita consumers of apples in the world, and they’re conducting some of the most progressive research in apples.”
Of course, one might wonder why a tiny country like the Netherlands, with only 16.5 million residents, or less than 0.03 percent of the world’s population, has pushed itself into the forefront of solving all of these looming problems in the world’s food supply. The first clue is that Holland since its golden age in the 18th century has dominated European trade and today runs the world’s largest wholesale food exchange (followed by Shanghai). But that’s not all, says Willem Stiekema, director of the Wageningen University’s Center for Bio-System Genomics: “We Dutch are a different breed. That’s true. We are a rather inquisitive and experimenting people—so why not?”
Frank Browning has reported on science, social, and cultural matters for NPR since 1983. He lives in Paris but spends time in Kentucky, where he makes hard cider. He is the author of six books including The Culture of Desire and Apples: Story of the Fruit of Temptation.