nsf.gov - National Science Foundation - Keeping pace with plant pathogens

Plant immune system research ready for application, say researchers.-

Late-blight-resistant potato plants, on left, compared with potatoes suffering from the disease Credit and Larger Version

August 15, 2013

In the battle between diseases and plants--constant, changing and centuries old--scientists and farmers usually arm themselves through classical breeding, crossing varieties in the hopes of eventually reaching disease resistance. With advances in DNA sequencing and genetics, however, they may soon have a more sophisticated weapon: disease-resistant seeds.

Basic research on the genetic gears of plant immune systems has advanced so much that scientists can now begin applying that knowledge, building healthier plants to decrease dependence on pesticides, water overuse and help agriculture in developing countries, according to a paper in this week's edition of the journal Science.

"I think the backdrop is simple: We need to feed a lot of people, and we need to do it in a sustainable way," said Jeff Dangl, one of the paper's authors. He is a Howard Hughes Medical Institute investigator and biology professor at the University of North Carolina. "We need to feed them in a way that we use no more land than we use now. We need to do it more efficiently, and we need to do it in the face of ever-evolving pathogens."

The paper was also authored by Brian Staskawicz, plant and microbial biology professor at the University of California, Berkeley, and Diana Horvath, director of the Two Blades Foundation, a Chicago-area nonprofit promoting plant disease resistance research and application. NSF funds have helped fuel the research of all three.

The paper synthesizes two decades of research on plant immune systems, looking at "where technology has been applied, and what the future can be," said Staskawicz.

For more than a century, disease resistance in plants has been achieved through traditional breeding, a process that requires the "patience of Job," Dangl said. "Imagine waiting till you get to your grandchildren to see how your offspring turn out."

Disease-causing microbes multiply much, much faster. Modern agriculture--predominately single crops grown over many acres instead of the diversity hodgepodge seen in nature--also favors pathogens, microbial agents that cause disease.

Globally, about 15 percent of crop harvests are lost each year due to disease, but destruction varies greatly from crop to crop. Cassava blight, which attacks a staple food source in many developing countries, can destroy 20 to 100 percent of crops. Most loss occurs late in a crop's life, gallons and gallons and gallons of water in. "Plant diseases are a huge waste of water," Dangl said.

To combat pathogens, farmers rely on disease-resistant plant varieties--cultivated by careful, slow breeding--and pesticides. Both are far from foolproof. Pathogens evolve to outwit breeding and pesticides often carry harmful environmental side effects. Some farmers, like those in developing countries, also can't afford them. Creating disease resistant seeds, requiring little-to-no pesticides and no unfamiliar agricultural techniques, is "a simple and effective way to help farmers in developing countries," Horvath said.

Classical breeding has given plant researchers a wealth of genetic material, developed over generations, with which to breed disease resistant varieties. Combined with leaps and bounds in genetics research and quicker, cheaper DNA sequencing, scientists have learned how to build stronger plant varieties. They have pinpointed special receptors, housed both inside and outside plant cells, which scan for infection; launching the attack when a pathogen is found. They've identified disease-resistant genes housed in the molecular architecture of different plants. These genes can confer resistance to dangers such as wheat rust, powdery mildew and bacterial spot disease.

"We now know enough about the key molecules in the plant immune system that we can actually start to deploy what we've learned," said Dangl. This includes genetic editing--removing disease-prone genes--or mining disease-resistance genes from various plants and adding them into other crops. Combining a few disease-resistance genes would bolster plant immunity to multiple diseases, similar to the chemical cocktail developed to fight AIDS.

The ultimate objective is to build "predictive, highly refined molecular plant breeding that includes disease resistance," Dangl said. It's essentially an updated version of classical breeding, injecting genetic know-how into seed creation using disease-resistance genes from plants people eat every day: wheat, rice, pepper, tomato and others.

This has already been successful. Disease resistance genes bred into papaya helped save Hawaii's papaya industry from a ringspot virus in the mid-90s. Staskawicz and Horvath also worked to develop tomato plants resistant to bacterial pathogens. In Florida field tests, the modified varieties have higher yields and don't require harmful copper pesticides.

Still, researchers have much to learn. How all these disease resistance genes function, on a molecular basis, is to be discovered.  Staskawicz compares it to watching TV. You know if you press a certain button, the TV comes on, without understanding any mechanics behind the screen. "You can still use the gene without knowing exactly how it works," he said. Pathogens will also continue evolving, slowly subverting genetic disease resistance, engineered or not. "It's a constantly evolving process," Staskawicz said.

There are no simple solutions, said Michael Mishkind, a program director in NSF's Biological Sciences Directorate. Yet our current level of understanding of disease resistance mechanisms "speaks eloquently to the importance of basic research. Years of fundamental study of the plant immune system have added a powerful set of tools, helping us keep ahead of the pathogens that threaten our food supply."

-NSF-

Media Contacts Jessica Arriens, NSF (703) 292-2243

 jarriens@nsf.gov

Related WebsitesTwo Blades Foundation:

 http://2blades.org/
Staskawicz Laboratory, UC-Berkeley:

 http://www.staskawiczlab.org/
Jeff Dangl, Howard Hughes Medical Institute: 

http://www.hhmi.org/scientists/jeffery-l-dangl

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) 2012, its budget was $7.0 billion. NSF funds reach all 50 states through grants to nearly 2,000 colleges, universities and other institutions. Each year, NSF receives about 50,000 competitive requests for funding, and makes about 11,500 new funding awards. NSF also awards about $593 million in professional and service contracts yearly.

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The effects of bacterial leaf spot disease on regular tomatoes (on top) and genetically altered ones
Credit and Larger Version

The researchers' work is described in the Aug. 16, 2013, issue of the journal Science.
Credit and Larger Version

The National Science Foundation (NSF).

Guillermo Gonzalo Sánchez Achutegui

ayabaca@hotmail.com

ayabaca@gmail.com

ayabaca@yahoo.com

nsf.gov - National Science Foundation : NSF, USDA, DOE Award Grants to Improve Predictions of Climate Change on Regional, Decadal Scales

Research will lead to better understanding of climate change effects on shorter, more local scales,-

Simulation of surface temperature changes due to aerosols from Northern Hemisphere fires. Credit: Yongjia Song and Yuhang Wang, Georgia Institute of Technology

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EaSM researchers will assess how climate change affects prairie pothole wetlands. Credit: Ducks Unlimited

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Water: more precious than gold. Will there be enough in longer times of drought? Credit: Wikimedia Commons

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EaSM grantees will study wildfires and regional climate variability. Credit: Wikimedia Commons

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Scorched Earth: drought in the Sonoran Desert cracks open the land. Credit: Wikimedia Commons

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Hot time in the city: How will climate change affect urban and surrounding areas? Credit: NSF Central Arizona-Phoenix Long-Term Ecological Research Site

Download the high-resolution JPG version of the image. (100 KB) What will Earth's climate be like in a decade--or sooner? And what will it be like where you live, and around the globe? To help find answers, the National Science Foundation (NSF) and other federal agencies have awarded new grants to study the consequences of climate variability and change. The awards were made through the interagency Decadal and Regional Climate Prediction Using Earth System Models (EaSM) Program. At NSF, EaSM is part of the Science, Engineering and Education (SEES) portfolio of investments. "NSF is strongly supportive of the EaSM goal of improved understanding of the climate system," says Roger Wakimoto, NSF assistant director for Geosciences. "Better climate predictions will arm decision-makers with the quantitative information they need to help chart the appropriate future course for society," says Wakimoto. Other agencies awarding grants in the interagency EaSM Program are the U.S. Department of Agriculture (USDA) and the U.S. Department of Energy (DOE). NSF has invested $22.7 million in the awards; USDA, $5.2 million; and DOE, $3.3 million. Among the subjects addressed by the EaSM awards are: Quantifying and conveying the risk of prolonged drought in coming decades, Exploring the connection between wildfires and regional climate variability, Linking near-term future changes in weather and hydroclimate in Western North America to adaptations for ecosystem and water resource management, Advancing climate and regional model validation for societal applications, and Connecting human and Earth system models to assess regional effects and adaptations in urban systems and their hinterlands. According to scientists, the EaSM program addresses one of the most pressing problems of the millennium: climate change and how it is likely to affect the world--and how people can plan for its consequences. That challenge calls for the development of next-generation Earth system models that include coupled and interactive representations of ecosystems, agricultural working lands and forests, urban environments, biogeochemistry, atmospheric chemistry, ocean and atmospheric currents, the water cycle, land and sea ice and human activities. EaSM projects will expand the limits of scientists' understanding of Earth's climate system, leading to better ways of predicting climate change. The consequences of climate variability and change are becoming more immediate and profound than anticipated, research has found. Prolonged droughts on several continents, increasing stresses on natural and managed ecosystems, losses of agricultural and forest productivity, degraded ocean and permafrost habitats, global sea-level rise, the rapid retreat of ice sheets and glaciers, and changes in ocean currents have shown that climate variability and change will likely have significant effects on decade and shorter time scales. Those effects on humans and other animals, plants, and planet-wide systems such as the oceans, may be far-reaching. Among the goals of the EaSM program is achieving reliable global and regional predictions of decadal climate variability and change through an understanding of the coupled physical, chemical, biological and human processes that drive the climate system. Awardees are working to quantify the effects of climate variability and change on ecological, agricultural and other human systems, and to identify and quantify "feedback loops" through which humans affect the environment. "As climate becomes more variable, precipitation extremes become more frequent and temperatures rise, agricultural producers, foresters and natural resource managers will need to plan and adapt in order to meet the needs of Earth's population," says Sonny Ramaswamy, director of the National Institute of Food and Agriculture at the U.S. Department of Agriculture. "Understanding the climate system and being able to predict climate trends on decadal and regional scales will be important to helping the agriculture industry remain profitable. These grants will help us move science forward so we can make the best decisions for adaptive management and planning for the future." Adds Sharlene Weatherwax, DOE associate director for Biological and Environmental Research, "To advance a robust predictive understanding of Earth's climate, and to inform the development of sustainable solutions to our energy and environmental challenges, a deeper understanding of natural climate variability and change is needed. "The projects DOE supports through EaSM are expected to efficiently enhance the ability to design and deploy the most effective energy solutions for the nation." Scientists are maximizing observational and model data for impact and vulnerability/resilience assessments, and translating model results and their uncertainties into the scientific basis for well-informed human adaptation to and management decisions for climate change. These decisions need to happen, say climate researchers, in the coming years--not decades or centuries. 2013 NSF-USDA-DOE EaSM Awards Collaborative Research EaSM2: Mechanisms, Predictability, Prediction, and Regional and Societal Impacts of Decadal Climate Variability: Gokhan Danabasoglu, UCAR Collaborative Research: EaSM2--Quantifying and Conveying the Risk of Prolonged Drought in Coming Decades: Jonathan Overpeck, University of Arizona Collaborative Research: EaSM2--Linking Near Term Future Changes in Weather and Hydroclimate in Western North America to Adaptation for Ecosystem and Water Management:    Richard Seager, Columbia University Collaborative Research: EaSM2--Advanced Climate and Regional Model Validation for Societal Applications:  Lawrence Buja, UCAR Collaborative Research: EaSM 2: Stochastic Simulation and Decadal Prediction of Large-Scale Climate: Dmitri Kondrashov, University of California, Los Angeles Collaborative Research: EaSM2--Wildfires and Regional Climate Variability - Mechanisms, Modeling, and Prediction:   Yuhang Wang, Georgia Tech (jointly funded with DOE) Collaborative Research: EaSM2--Linking Human and Earth System Models to Assess Regional Impacts and Adaption in Urban Systems and Their Hinterlands:  Brian O'Neill, UCAR Collaborative Research: EaSM 2 Advancing extreme value analysis of high impact climate and weather events: Daniel Cooley, Colorado State University (jointly funded with DOE) Attribution of changes in precipitation intensity over the central US (USDA-funded):  Ray Arritt, Iowa State Forest Die-off, Climate Change, and Human Intervention in Western North America (USDA-funded): Phil Mote, Oregon State University -NSF- Media Contacts Cheryl Dybas, NSF (703) 292-7734 cdybas@nsf.gov Related WebsitesNSF Science, Engineering and Education for Sustainability (SEES) Investment: http://www.nsf.gov/sees NSF/EaSM Discovery Article: The Snows of Mount Washington: http://www.nsf.gov/discoveries/disc_summ.jsp?cntn_id=123363&org=NSF NSF Publication: Discoveries in Sustainability: http://www.nsf.gov/pubs/2012/disco12001/disco12001.pdf 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) 2012, its budget was $7.0 billion. NSF funds reach all 50 states through grants to nearly 2,000 colleges, universities and other institutions. Each year, NSF receives about 50,000 competitive requests for funding, and makes about 11,500 new funding awards. NSF also awards about $593 million in professional and service contracts yearly. Get News Updates by Email Useful NSF Web Sites: NSF Home Page:  http://www.nsf.gov NSF News: http://www.nsf.gov/news/ For the News Media: http://www.nsf.gov/news/newsroom.jsp Science and Engineering Statistics: http://www.nsf.gov/statistics/ Awards Searches:  http://www.nsf.gov/awardsearch/

The National Science Foundation (NSF).-

 

Guillermo Gonzalo Sánchez Achutegui

ayabaca@gmail.com

ayabaca@hotmail.com

ayabaca@yahoo.com

nsf.gov - News - Changing Atmosphere Affects How Much Water Trees Need

Increasing levels of atmospheric carbon dioxide alter how plants use water.-

Above the forest canopy: looking down at the trees from a Michigan eddy-covariance tower. Credit: Chris Vogel Download the high-resolution version of the image. (437 KB)   Summer turns to fall: another view over the forest from the eddy-covariance tower. Credit: Chris Vogel Download the high-resolution version of the image. (283 KB)

A sonic aerometer for monitoring gas exchange between the forest and the atmosphere. Credit: Chris Vogel

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View from the top of an eddy-covariance tower of a boreal forest in Maine. Credit: David Hollinger Download the high-resolution version of the image. (4.5 MB)

On the ground: looking into Harvard Forest's trees from a less lofty perch. Credit: NSF Harvard Forest LTER Site

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Spurred by increasing levels of atmospheric carbon dioxide, forests over the last two decades have become dramatically more efficient in how they use water.

Scientists affiliated with the National Science Foundation's (NSF) Harvard Forest Long-Term Ecological Research (LTER) site report the results in this week's issue of the journal Nature.

Harvard Forest is one of 26 such NSF LTER sites in ecosystems from deserts to grasslands, coral reefs to coastal waters, around the world.

Studies have long predicted that plants would begin to use water more efficiently, that is, lose less water during photosynthesis, as atmospheric carbon dioxide levels rose.

A research team led by Trevor Keenan and Andrew Richardson of Harvard University, however, has found that forests across the globe are losing less water than expected and becoming even more efficient at using it for growth.

Using data collected in forests in the northeastern United States and elsewhere around the world, Keenan and Richardson found increases in efficiency larger than those predicted by state-of-the-art computer models.

The research was done in collaboration with scientists from the USDA Forest Service, Ohio State University, Indiana University and the Karlsruhe Institute of Technology in Germany.

"This could be considered a beneficial effect of increased atmospheric carbon dioxide," said Keenan, the first author of the Nature paper.

"What's surprising is we didn't expect the effect to be this big. A large proportion of the ecosystems in the world are limited by water--they don't have enough water during the year to reach their maximum potential growth.

"If they become more efficient at using water, they should be able to take more carbon out of the atmosphere due to higher growth rates."

While increased atmospheric carbon dioxide may benefit forests in the short-term, Richardson emphasized that the overall climate picture would remain grim if levels continue to rise.

"We're still very concerned about what rising levels of atmospheric carbon dioxide mean for the planet," Richardson said.

"There is little doubt that as carbon dioxide continues to rise--and last month we just passed a critical milestone, 400 parts per million for the first time in human history--rising global temperatures and changes in rainfall patterns will, in coming decades, have very negative consequences for plant growth in many ecosystems around the world."

How do increasing carbon dioxide levels lead to more efficient water use?

The answer, Keenan said, is in the way photosynthesis works.

To take in the carbon dioxide they need, plants open tiny pores, called stomata, on their leaves. As carbon dioxide enters, however, water vapor is able to escape.

Higher levels of carbon dioxide mean the stomata don't need to open as wide, or for as long, so the plants lose less water and grow faster.

To take advantage of that fact, commercial growers have for years pumped carbon dioxide into greenhouses to promote plant growth.

To test whether such a "carbon dioxide fertilization effect" was taking place in forests, Keenan, Richardson and others turned to long-term data measured using a technique called eddy covariance.

This method, which relies on sophisticated instruments mounted on tall towers extending above the forest canopy, allows researchers to determine how much carbon dioxide and water are going into and out of the ecosystem.

With more than 20 years of data, the towers at the NSF Harvard Forest LTER site--which have the longest continuous record in the world--are an important resource for studying how forests have responded to changes in atmospheric carbon dioxide levels, scientists say.

"A goal of the NSF LTER program is understanding forest ecosystems and the basis for predicting fluxes of energy and materials in these ecosystems," said Matt Kane, program director in NSF's Division of Environmental Biology, "as well as distributions of forest biota as a result of global climate change."

"Findings from this study are important to our understanding of forest ecosystems--and how they can be managed more effectively now and in the future."

Though more than 300 towers like Harvard Forest's have sprung up around the globe, many of the earliest--and hence with the longest data records--are in the northeastern United States.

When the researchers began to look at those records, they found that forests were storing more carbon and becoming more efficient in how they used water.

The phenomenon, however, wasn't limited to a single region. When the scientists examined long-term data sets from all over the world, the same trend was evident.

"We went through every possible hypothesis of what could be going on, and ultimately what we were left with is that the only phenomenon that could cause this type of shift in water-use efficiency is rising atmospheric carbon dioxide," Keenan said.

Going forward, Keenan, who is now at Macquarie University in Sydney, Australia, is working to get access to data collected from yet more sites, including several that monitor tropical and arctic systems.

"This larger dataset will help us better understand the extent of the response we observed," he said.

"That in turn will help us build better models, and improve predictions of the future of the Earth's climate.

"Right now, all the models we have underrepresent this effect by as much as an order of magnitude, so the question is: What are the models not getting? What do they need to incorporate to capture this effect, and how will that affect their projections for climate change?"

The research was also supported by NOAA. Field measurements at the sites, which are part of the AmeriFlux network, have also been funded by the U.S. Department of Energy and the USDA Forest Service.

-NSF-

Media Contacts Cheryl Dybas, NSF (703) 292-7734

 cdybas@nsf.gov
Peter Reuell, Harvard University (617) 496-8070

preuell@fas.harvard.edu

Related WebsitesNSF Long-Term Ecological Research Network

 http://www.lternet.edu
NSF Harvard Forest LTER Site:

http://harvardforest.fas.harvard.edu/research/LTER
NSF Discovery Article: The Colors of Fall: Are Autumn Reds and Golds Passing Us By?:

 http://www.nsf.gov/discoveries/disc_summ.jsp?cntn_id=125511
NSF Publication: Discoveries in Long-Term Ecological Research:

 http://www.nsf.gov/pubs/2013/nsf13083/nsf13083.pdf?WT.mc_id=USNSF_25&WT.mc_ev=click

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) 2012, its budget was $7.0 billion. NSF funds reach all 50 states through grants to nearly 2,000 colleges, universities and other institutions. Each year, NSF receives about 50,000 competitive requests for funding, and makes about 11,500 new funding awards. NSF also awards about $593 million in professional and service contracts yearly.

Get News Updates by Email

Useful NSF Web Sites:
NSF Home Page:

http://www.nsf.gov
NSF News:

http://www.nsf.gov/news/
For the News Media:

 http://www.nsf.gov/news/newsroom.jsp
Science and Engineering Statistics:

 http://www.nsf.gov/statistics/
Awards Searches:

 http://www.nsf.gov/awardsearch/

The National Science Foundation (NSF).-
Guillermo Gonzalo Sánchez Achutegui
ayabaca@gmail.com
ayabaca@hotmail.com
ayabaca@yahoo.com

Science: Biologists Replicate Key Evolutionary Step in Life on Earth

Hi My Friends: AL VUELO DE UN QUINDE EL BLOG., More than 500 million years ago, single-celled organisms on Earth's surface began forming multi-cellular clusters that ultimately became plants and animals.

Green cells are undergoing cell death, a cellular division-of-labor--fostering new life.

Credit: Will Ratcliff and Mike Travisano

Multi-cellular 'snowflake' yeast images with a blue cell-wall stain and red dead-cell stain.

Credit: Will Ratcliff and Mike Travisano
First steps in the transition to multi-cellularity: 'snowflake' yeast with dead cells stained red.

Credit: Will Ratcliff and Mike Travisano

A multi-cellular yeast consisting of hundreds of cells.

Credit: Will Ratcliff and Mike Travisano Multi-cellular yeast individuals containing central dead cells, which promote reproduction.

Credit: Will Ratcliff and Mike Travisano Aberrant shapes of multi-cellular yeast's dead cells: break points for reproduction.

Credit: Will Ratcliff and Mike Travisano

More than 500 million years ago, single-celled organisms on Earth's surface began forming multi-cellular clusters that ultimately became plants and animals.
Just how that happened is a question that has eluded evolutionary biologists.
Now scientists have replicated that key step in the laboratory using common Brewer's yeast, a single-celled organism.
The yeast "evolved" into multi-cellular clusters that work together cooperatively, reproduce and adapt to their environment--in essence, they became precursors to life on Earth as it is today.
The results are published in this week's issue of the journal Proceedings of the National Academy of Sciences (PNAS).
"The finding that the division-of-labor evolves so quickly and repeatedly in these 'snowflake' clusters is a big surprise," says George Gilchrist, acting deputy division director of the National Science Foundation's (NSF) Division of Environmental Biology, which funded the research.
"The first step toward multi-cellular complexity seems to be less of an evolutionary hurdle than theory would suggest," says Gilchrist. "This will stimulate a lot of important research questions."
It all started two years ago with a casual comment over coffee that bridging the famous multi-cellularity gap would be "just about the coolest thing we could do," recalled Will Ratcliff and Michael Travisano, scientists at the University of Minnesota (UMN) and authors of the PNAS paper.
Other authors of the paper are Ford Denison and Mark Borrello of UMN.
Then came the big surprise: it wasn't that difficult.
Using yeast cells, culture media and a centrifuge, it only took the biologists one experiment conducted over about 60 days.
"I don't think anyone had ever tried it before," says Ratcliff. "There aren't many scientists doing experimental evolution, and they're trying to answer questions about evolution, not recreate it."
The results have earned praise from evolutionary biologists around the world.
"To understand why the world is full of plants and animals, including humans, we need to know how one-celled organisms made the switch to living as a group, as multi-celled organisms," says Sam Scheiner, program director in NSF's Division of Environmental Biology.
"This study is the first to experimentally observe that transition," says Scheiner, "providing a look at an event that took place hundreds of millions of years ago."
In essence, here's how the experiments worked:
The scientists chose Brewer's yeast, or Saccharomyces cerevisiae, a species of yeast used since ancient times to make bread and beer because it is abundant in nature and grows easily.
They added it to nutrient-rich culture media and allowed the cells to grow for a day in test tubes.
Then they used a centrifuge to stratify the contents by weight.
As the mixture settled, cell clusters landed on the bottom of the tubes faster because they are heavier. The biologists removed the clusters, transferred them to fresh media, and agitated them again.
Sixty cycles later, the clusters--now hundreds of cells--looked like spherical snowflakes.
Analysis showed that the clusters were not just groups of random cells that adhered to each other, but related cells that remained attached following cell division.
That was significant because it meant that they were genetically similar, which promotes cooperation. When the clusters reached a critical size, some cells died off in a process known as apoptosis to allow offspring to separate.
The offspring reproduced only after they attained the size of their parents.
"A cluster alone isn't multi-cellular," Ratcliff says. "But when cells in a cluster cooperate, make sacrifices for the common good, and adapt to change, that's an evolutionary transition to multi-cellularity."
In order for multi-cellular organisms to form, most cells need to sacrifice their ability to reproduce, an altruistic action that favors the whole but not the individual, Ratcliff says.
For example, all cells in the human body are essentially a support system that allows sperm and eggs to pass DNA along to the next generation.
Thus multi-cellularity is by its nature very cooperative.
"Some of the best competitors in nature are those that engage in cooperation, and our experiment bears that out," says Travisano.
Evolutionary biologists have estimated that multi-cellularity evolved independently in about 25 groups.
Travisano and Ratcliff wonder why it didn't evolve more often since it's not that difficult to recreate in a lab.
Considering that trillions of one-celled organisms lived on Earth for millions of years, it seems like it should have, Ratcliff says.
That may be a question the biologists will answer in the future using the fossil record for thousands of generations of multi-cellular clusters, which are stored in a freezer in Travisano's lab.
Since the frozen samples contain multiple cell lines that independently became multi-cellular, the researchers can compare them to learn whether similar or different mechanisms and genes were responsible in each case, Travisano says.
The next steps will be to look at the role of multi-cellularity in cancer, aging and other critical areas of biology.
"Multi-cellular yeast is a valuable resource for investigating a wide variety of medically and biologically important topics," Travisano says.
"Cancer was recently described as a fossil from the origin of multi-cellularity, which can be directly investigated with the yeast system.
"Similarly the origins of aging, development and the evolution of complex morphologies are open to direct experimental investigation that would otherwise be difficult or impossible."
-NSF-
Guillermo Gonzalo Sánchez Achutegui
ayabaca@gmail.com
ayabaca@hotmail.com
ayabaca@yahoo.com