The National Science Foundation (NSF): Scientists develop genetic path to tastier tomatoes.- Científicos desarrollan un camino genético hacia tomates más sabrosos

https://www.nsf.gov/news/news_summ.jsp?cntn_id=190832&WT.mc_id=USNSF_51&WT.mc_ev=click

Consumers craving more flavorful tomatoes could get them

Researchers subjected many tomato varieties to consumer panel evaluations. Credit and Larger Version

January 26, 2017

Some consumers crave tastier tomatoes than those available at the supermarket. Now, scientists at the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) and their partners have found a way to get tomatoes to produce the compounds that make them more flavorful.

Their findings were published today in the journal Science.

"Around the world, the tomato is one of the most popular foods," says Gert de Couet, director of the National Science Foundation (NSF) Division of Integrative Organismal Systems, which supported the research. "This state-of-the-art analysis sets the stage to return it to the taste of decades ago by breeding informed by molecular genetics."

Step one for UF/IFAS horticultural scientist Harry Klee and his colleagues involved finding out which of the hundreds of chemicals in a tomato contribute the most to taste.

Next, Klee said, they asked: "What's wrong with modern tomatoes?" As it turned out, modern tomatoes lack sufficient sugars and volatile chemicals critical to better flavor. Those traits have been lost over the past 50 years, says Klee, the Science paper's lead author.

The researchers began looking at tomato alleles (one of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome). Alleles determine specific traits in organisms, whether tomatoes or people. Klee likened this to how different versions of genes in humans influence traits such as height, weight and hair color.

"We wanted to identify why modern tomato varieties are deficient in flavor chemicals," Klee said. "It's because they have lost the more desirable alleles of a number of genes."

The scientists then zeroed in on the locations of those alleles in the tomato genome. Using a technique called a genome-wide association study, they mapped genes that control synthesis of all the "tasty" chemicals. Informed by genetic analysis, they replaced undesirable alleles in modern tomato varieties with desirable alleles.

"We identified the important factors that have been lost and showed how to move them back into modern types of tomatoes," Klee said. "We're just fixing what has been damaged over the last half-century to push them back to where they were, taste-wise. We can make the supermarket tomato taste noticeably better."

Breeding a more flavorful tomato could benefit consumers as well as the tomato industry. According to the Department of Agriculture, the U.S. is second only to China in worldwide tomato production.

Florida and California account for up to three-quarters of all commercially produced fresh tomatoes in the U.S. As of 2014, Florida growers produced 33,000 acres of tomatoes worth $437 million annually, according to UF/IFAS research.

But breeding a better tomato will take time, Klee says. The genetic traits discovered in the study may take three or four years to produce new varieties.

-NSF-

Media Contacts Cheryl Dybas, NSF, (703) 292-7734, cdybas@nsf.gov
Brad Buck, UFL, (352) 294-3303, bradbuck@ufl.edu

Related WebsitesNSF Grant: Regulating Tomato Quality through Expression: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1539831&HistoricalAwards=false

The National Science Foundation (NSF) is an independent federal agency that supports fundamental research and education across all fields of science and engineering. In fiscal year (FY) 2016, its budget is $7.5 billion. NSF funds reach all 50 states through grants to nearly 2,000 colleges, universities and other institutions. Each year, NSF receives more than 48,000 competitive proposals for funding and makes about 12,000 new funding awards. NSF also awards about $626 million in professional and service contracts yearly.

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Scientist Harry Klee and his colleagues identified genes crucial to tomato flavor.
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Compounds associated with flavor are collected and analyzed in the lab using gas chromatography.
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Biologists have shown that chilling tomatoes reduces their flavor quality.
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Harry Klee in the midst of his research subjects: flowering tomato plants.
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The wild progenitor of the tomato, Solanum pimpinellifolium.
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The National Science Foundation (NSF)
Guillermo Gonzalo Sánchez Achutegui
ayabaca@gmail.com
ayabaca@hotmail.com
ayabaca@yahoo.com
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nsf.gov - National Science Foundation - Staple of recipe favorites--the tomato--reveals processes that maintain biodiversity

No hothouse plants: Study examines supermarket tomatoes' wild relatives, which live in Earth's most extreme environments

Wild tomatoes are small plants with big messages. Credit and Larger Version

December 5, 2013

The following is part twelve in a series on the National Science Foundation's Science, Engineering and Education for Sustainability (SEES) investment. Visit parts one, two, three, four, five, six, seven, eight, nine, ten and eleven in this series.

Tomatoes are in almost everything we eat, from salad and soup to chili and pizza. For some, tomato-based dishes are featured during the holiday season.

Most people don't realize, however, that there are more than a dozen wild tomato species, or that wild tomatoes grow in the deserts, rainforests and highlands of South America and on the Galapagos Islands.

These wild species don't have the big, bold fruits we're used to seeing in the supermarket, though. Wild tomato fruits are smaller, from the size of a pea to that of a large marble and are sometimes green and bitter when they're ripe.

But compared with their domesticated relatives, wild tomatoes are more diverse in many hidden and not-so-hidden ways.

Now scientists are using the genomes of wild tomatoes to study the processes that drive Earth's biodiversity.

Their goal is to learn how species cope with differences in climate and natural enemies, and what might happen in this time of environmental change.

 

Wild tomato genomes as a framework for understanding biodiversity

To study natural trait and genome diversity in wild tomatoes, scientists Leonie Moyle, David Haak and Matthew Hahn of Indiana University Bloomington received a grant from the National Science Foundation's (NSF) Dimensions of Biodiversity program.

Dimensions of Biodiversity is part of NSF's Science, Engineering and Education for Sustainability investment and is supported by NSF's Directorates for Biological Sciences and Geosciences.

Scientists funded through Dimensions of Biodiversity integrate genetic, taxonomic and functional approaches in their research.

"The resulting discoveries go beyond expanding our knowledge of the depth and breadth of life on Earth," says John Wingfield, NSF assistant director for Biological Sciences.

"They have the potential to revolutionize the way we manage agriculture, practice medicine, address global climate change and develop new technologies."

The award to Moyle's team funds sequencing of the complete set of all expressed genes (the transcriptome) in populations of wild tomato species.

"Variations within and between these wild tomato genomes can be compared by using the genome sequence of the domesticated tomato as a 'backbone,'"says Moyle.

By linking this genome-wide sequence data with information on wild tomato trait variation, the biologists hope to identify the genes responsible for adaptation to environmental change.

The research focuses on the role of drought and of defense against herbivores, or plant-eaters, in the diversity of wild tomatoes.

"These factors," says Haak, "capture two of the most important aspects of any plant's environment: climate and natural enemies."

 

Wild tomatoes: From hothouse to deep freeze

While domesticated tomatoes thrive only in agricultural irrigation, wild tomatoes live in some of the planet's most extreme environments.

They're among the few plants found in the driest place on Earth--the Atacama Desert in Chile. Other wild tomatoes blossom along the rocky, salty shores of the Galapagos Islands, and in the daily rains of Ecuador's rainforests.

But it's not just the climate in which they grow that varies among wild tomatoes.

The plants bristle with an array of natural defenses, from dense coverings of plant hairs to toxins deadly against insect attackers.

 

Measuring biodiversity in plant defenses

In a forthcoming paper in the journal Ecology, Haak, Moyle and colleagues document large differences in defenses among wild tomatoes.

They used bioassays--experiments in which living organisms are used to reveal the potency or concentration of a substance.

In this case, they fed leaf samples of different wild tomato species to tobacco hornworms.

The tobacco hornworm--also known as the tomato hornworm--is an enemy of both domesticated and wild tomatoes. It rapidly eats its way through the plants' leaves.

Each hornworm caterpillar was weighed before and after feeding to determine how much it had gained on a diet of wild tomato leaves.

Those tomatoes on which caterpillars gained little or no weight, says Haak, have more natural defenses than those on which the caterpillars gained weight.

In one wild tomato species, caterpillars lost significant weight; they refused to consume the plant's toxic leaves.

The researchers showed that the level of natural defense varies widely among wild tomato species.

"Although all wild tomatoes are closely related, these patterns of defense variation don't simply follow historical, evolutionary relationships," says Moyle. "The defense level of each wild tomato population is likely shaped by responses to local herbivores."

 

Linking biodiversity to genomics to understand environmental responses

Moyle and Haak are using DNA sequencing to look at the genes that are expressed differently in wild tomatoes with varying levels of natural defenses, and with differences in responses to drought.

Genes that are consistently up- or down-regulated in these conditions, says Moyle, can reveal the changes important for responding to and coping with environmental stresses.

"By linking data on DNA sequence variation, and on variation in gene expression, with wild tomatoes' responses to drought and natural enemies," she says, "we may find a powerful model for understanding the genetics of responses to environmental change."

The study could also uncover genetic variations helpful in improving domesticated tomatoes and their cultivated relatives, including potatoes and peppers.

"This research on tomatoes' wild relatives offers insights into the huge reservoir of genetic information available to ensure our future food security," says Simon Malcomber, lead NSF program director for Dimensions of Biodiversity.

"Tomatoes are one of the most widely consumed foods around the world," he says. "Studies such as this provide important information that could be used to improve herbivore resistance in crop cultivars."

Next time you're in the supermarket, tomatoes are worth a closer look. These common plants may offer a glimpse of our global food security, and of Earth's environmental future.

--	Cheryl Dybas, NSF (703) 292-7734   cdybas@nsf.gov

Investigators David Haak
Leonie Moyle
Matthew Hahn

Related Institutions/Organizations Indiana University

Related Programs Dimensions of Biodiversity

Related Awards#1136707 Dimensions: Integrating dimensions of Solanum biodiversity: leveraging comparative and experimental transcriptomics to understand functional responses to environmental change

Total Grants $1,182,938

Related WebsitesIn race against time, NSF grants fund research on Earth's threatened biodiversity:

 http://www.nsf.gov/news/news_summ.jsp?cntn_id=129242
Stemming the Tide of Biodiversity Loss on Earth:

 http://www.nsf.gov/news/news_summ.jsp?cntn_id=125495&org=NSF&from=news
Diversity of Life on Earth: NSF Awards Grants for Study of Dimensions of Biodiversity:

 http://www.nsf.gov/news/news_summ.jsp?cntn_id=122098
NSF Awards Grants to Study Dimensions of Earth's Biodiversity:

 http://www.nsf.gov/news/news_summ.jsp?cntn_id=117811&org=NSF&from=news
Earth Week: A Stream Is a Stream Is a Stream: Or Is It?:

 http://www.nsf.gov/discoveries/disc_summ.jsp?cntn_id=123855&org=NSF
NSF Publication: "Discoveries in Sustainability":

 http://www.nsf.gov/pubs/2012/disco12001/disco12001.pdf
Biodiversity of Earth's Richest Plant Kingdom Under Fire:

 http://www.nsf.gov/discoveries/disc_summ.jsp?cntn_id=122938&org=NSF

Wild tomatoes (right) differ in size, taste, color from domesticated tomatoes (left).
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Sheena Shah, a researcher at Indiana University Bloomington, labels wild tomatoes in a greenhouse.
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Solanum pimpinellifolium, a wild tomato species, has red, sweet fruits.
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First the sweet, then the bitter: The green-striped, wild tomato Solanum peruvianum.
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Researcher Amanda Garbers of Indiana University Bloomington studies the DNA of wild tomato plants.
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The National Science Foundation

Guillermo Gonzalo Sánchez Achutegui

ayabaca@gmail.com

ayabaca@hotmail.com

ayabaca@yahoo.com  

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