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From Superseeds to Mutant Tomatoes

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August 20, 2010

By ROBIN FINN

WOODBURY, N.Y.

ZACHARY B. LIPPMAN, who favors hemp sandals, baggy khakis and an overgrown 5 o’clock shadow, is tending 40,000 tomato plants this summer, including 80 heirloom variants. He is in the second phase of his discovery of a genetic intervention that turns the average tomato plant into a bionic fruit factory. An international patent is, as the saying goes, pending.

“If I had a million dollars, I’d start a seed company tomorrow,” said Dr. Lippman, 32, a scientist with a hunch that the world is insatiable when it comes to tomatoes.

Dr. Lippman did his postdoctoral research on plum tomatoes in Rehovot, Israel, in conjunction with two top geneticists and mentors, Dani Zamir and Yuvel Eshed. (Their breakthrough research was published online in March in Nature Genetics.) Now working with his own team at Cold Spring Harbor Laboratory, he has been ramping up his efforts to decode the fruit-making process. In June, he published a pet project, the DNA sequence of the currant tomato — the wild ancestor of them all — online at the Sol Genomic Network, a database containing research on the nightshade family, of which tomatoes are a member.

Simply put, his achievement is this: By manipulating a single copy of a mutant gene, he can make a tomato plant increase its yield by half and simultaneously sweeten its produce. With a handful of his superseeds, a bag of cow manure and a sunny patch of dirt, someday any gardener may be able to do the same.

Told that his research — harnessing the phenomenon of hybrid vigor to harvest endless tomatoes — sounded like a pyramid scheme, Dr. Lippman played along. “I’m going to be in jail for committing tomato Ponzi,” he said, gently flicking a ladybug off his sleeve.

Dr. Lippman is farmer in chief of two greenhouses at the lab’s genome research center in nearby Woodbury, four acres of leased farmland in Riverhead, and a couple of acres at the Nature Conservancy’s Uplands Farm Sanctuary in Cold Spring Harbor. The lab hired him two years ago to expand his research into yields of tomato hybrids and various other plants, and he isn’t slacking; he smells of tomato plants, acrid and earthy, with a whiff of petunia and marigold for balance. His face is, no coincidence, tomato-hued from so much time in the fields.

Off duty — he lives on campus in Cold Spring Harbor with his wife, Shira, a dentist, and their four children — he hoards the seeds from every choice-looking fruit and vegetable he buys at the local Stop and Shop. For Dr. Lippman, a geneticist with a genuine food fascination, today’s experiment could be tomorrow’s salad.

“I’ve been grilling a lot of peppers this summer,” he said. Peppers, with only a single fruit per stem, are a future challenge.

An assistant professor at the lab who earned a doctorate from the Watson School of Biological Sciences there in 2004, Dr. Lippman was chagrined when, the day after his team’s research was published, a group of scientists spotted him and yelled, “Hey, Zach, nice tomatoes!”

“I don’t think they take tomatoes that seriously here,” he said, “but I’m doing something that I deem important. I don’t feel the need to justify it.”

He definitely has no need to plead his case before Bruce Stillman, the president of Cold Spring Harbor Laboratory, which has invested nearly $1 million in greenhouses alone.

“This is a result that screams out, ‘Hey, look at this!’ It’s extremely interesting and potentially of huge commercial value,” Dr. Stillman said.

Dr. Lippman had his “aha moment” in Israel, where he sifted through thousands of varieties of the humble plum tomato — and occasionally dodged missiles during the Lebanon conflict. “We joked that it counted as our military service,” he said.

He produced a strain of hyper-productive tomato seeds through his manipulation of a “flower power gene” known as S.F.T. (single flower truss), the “command gene” that tells plants when and how many flowers to generate. He is fixated on the potential of plant genetics to radically improve the yield not only of plum tomatoes but of boutique melons and mass-produced crops like soybeans.

“If this technology can be transferred to other species, it could be quite valuable, and that’s what Zach is working on now,” Dr. Stillman said.

Dr. Lippman’s parents, who do not garden, still live in Milford, Conn., where he grew up; he became interested in crop yields by working summers at a local farm during high school (where he grew a 620-pound pumpkin). As an undergraduate at Cornell he had his first exposure “to the genes that make extreme-sized fruits,” he said.

His crossing kit, a plastic box crammed with gadgets and a couple of green peppers whose seeds he intends to extract and study, serves as his briefcase. In it are a No. 5 tweezers, labels, string, a face mask (transplanting gets dusty) and a 20-year-old wood-handled pollinator that originated as a frog dissector but has been customized by having its needle-nose tip pounded flat. Finally, there is his pedigree list, which keeps track of the genetics of each plant and which bears a resemblance to a copy of The Daily Racing Form after it has been scrutinized and embellished with crib notes.

“The lifeblood of genetics is being able to pedigree,” he said, “but all we’re really doing is figuring out what Mother Nature and/or God have already done for us in a slow way, and we’re trying to understand and accelerate the process in a kosher way. No genetically modified tricks.”

He pointed to an ungainly bush, the progenitor of all domesticated tomatoes. “Currant tomatoes: basically just a bag of seeds waiting to be dispersed,” he said, squashing one to prove his point.

This summer’s most successful hybrids will produce at least 20 pounds of tomatoes per plant; seeds from the best of the bunch will be added to his personal stash of superperformers. But the experiment is not just about the harvest; it’s about controlling the flower-making process. Some plants will grow wispy and sterile, like the sad-looking mutant sequestered in a pot in the greenhouse for extended observation.

“We call him Wiry,” said Dr. Lippmann, who refers to his plants in the masculine gender, even petunias. He seems baffled by an accusation of sexism. “Technically they’re all hermaphrodites,” he said. “I don’t know why I call them ‘he’ and ‘him,’ I just do.” Some things defy scientific explanation.