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AgBioResearch News

Plant scientists find mechanism that gives plants 'balance'

When a plant goes into defense mode to protect itself against harsh weather or disease, that’s good for the plant but bad for the farmer growing the plant. Bad because, when a plant acts to defend itself, it turns off its growth mechanism.

MSU AgBioResearch scientist Sheng Yang He, is part of an international collaboration that has figured out how plants can make the “decision” between growth and defense, a finding that could help them strike a balance that keeps them safe from harm while continuing to grow.

Writing in the Proceedings of the National Academy of Sciences, He, an MSU professor of plant biology, and his team found that the two hormones that control growth (called gibberellins) and defense (known as jasmonates) literally come together in a crisis to determine the plant’s response.

“What we’ve discovered is that some key components of growth and defense programs physically interact with each other,” he said. “Communication between the two is how plants coordinate the two situations. We now know where one of the elusive molecular links is between growth and defense.”

This is important because now that scientists know that this happens, they can work to figure out how to “uncouple” the two, He added.

“Perhaps at some point we can genetically or chemically engineer the plants so they don’t talk to each other that much,” he said. “This way we may be able to increase yield and defense at the same time.”

In this way, He said plants are a lot like humans because we have only a certain amount of energy to use, and we have to make wise choices on how to use it.

“Plants, like people, have to learn to prioritize,” he explained. “You can use your energy for growth or use it for defense, but you can’t do them both at maximum level at the same time.”

The work was done on rice, a narrow-leafed plant, and Arabidopsis, which has a broader leaf. This was significant because it demonstrated that this phenomenon occurs in a variety of plant types.

He was one of the lead investigators on an international team of scientists that studied the issue. Other participating institutions are the Shanghai Institutes for Biological Sciences, Hunan Agricultural University, the University of Arkansas, Duke University, Yale University and Penn State University.

In addition to funding from AgBioResearch, funding for the project was provided by the National Institutes of Health, the U.S. Department of Energy and the Howard Hughes Medical Institute.

He is a Howard Hughes Medical Institute/Gordon and Betty Moore Foundation investigator. Earning the prestige honor last year, He is one of only 15 in the country.

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Silent Spring's 50th anniversary recognized on Earth Day 2012

Fifty years have passed since the publication of Rachel Carson’s “Silent Spring,” the book many credit with sparking the environmental movement – and an anniversary worth celebrating on Earth Day, April 22.

The book has deep connections to Michigan State University, from the late MSU ornithologist George Wallace’s research that was featured prominently in the book to the establishment of the Rachel Carson Chair in Sustainability at MSU and a legacy of environmental science research being conducted today.

Before Carson’s book, DDT was touted as a cure-all pesticide suitable for solving many of the world’s problems, including eliminating malarial mosquitoes, the beetles responsible for spreading Dutch elm disease and even treating lice on humans. To protect the stately elms that lined MSU’s campus drives, the university, like many other institutions and municipalities, used DDT liberally, employing misters to treat the trees.

“Silent Spring,” which is ranked No. 2 on New York University’s Top 100 Works of Journalism, is widely credited for opening the world’s eyes to the negative effects of many pesticides and helped lead to the banning of DDT in the United States in 1972. Wallace gave “Silent Spring” the living – and dying – imagery of flocks of terminal robins. His research showed that the unwitting birds, after feasting on DDT-filled worms, suffered seizures and died.

Wallace’s work and MSU’s legacy of environmental research is what attracted Thomas Dietz, MSU assistant vice president for environmental research, to the East Lansing campus. A prominent climate change researcher, Dietz understands researching a controversial subject in the face of zealous detractors.

“Her book, and others published at that time, transformed my interest from being purely scientific to a mix of science with the intent of providing good advice for policy,” said Dietz, an MSU AgBioResearch scientist. “Sadly, people attacked her personally and questioned her motives, as opposed to debating the science on which the book was based. It’s a sad pattern we still see today where, rather than work to come up with creative solutions related to climate change, people often bully and attack the messengers.”

He admires the work of Wallace, Carson and other scientists who conduct their research despite scathing attacks and, in some cases, even death threats, Dietz added.

Jianguo (Jack) Liu, an MSU AgBioResearch scientist and holder of the Rachel Carson Chair in Sustainability at MSU, remembers reading “Silent Spring” in college.

“Rachel Carson was a pioneer, and her work inspired me,” said Liu, who still has a first edition of “Silent Spring.” “As the first person to hold the Rachel Carson Chair in Sustainability, I am honored to continue her legacy, especially knowing the scrutiny she faced as a result of the book.”

Liu, after publishing a paper in Science, came under similar fire when he demonstrated that a world-famous giant panda reserve in China was not protecting the country’s iconic wildlife as intended.

“It took a long time for the government and many others to understand all of the issues involved,” Liu said. “But I am glad that there have been many positive changes – the co-author of the Science paper is the director of the reserve, several important policy changes have been implemented and the panda habitat has been improving.”

To view a video celebrating the 50th anniversary of Silent Spring, click here. 

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Busy queen bees maintain genetic diversity, health of their colonies

By mating with nearly 100 males, queen bees on isolated islands avoid inbreeding and keep colonies healthy.

These findings, published in a recent issue of PLoS ONE, focused on giant honey bee colonies on Hainan Island, off the coast of China. Because these bees have long been separated from their continental cousins, it was thought that the island bees would be prime candidates for inbreeding and have very different genes, said MSU AgBioResearch scientist Zachary Huang.

“We believed that the island bees would show evidence of the founder effect  -- random genetic changes in an isolated population -- on a unique sex determination gene from the mainland bees,” said Huang, an associate professor in the MSU Department of Entomology.  “At first we were surprised when we couldn’t document this effect. Looking at it further, I asked myself, ‘Why didn’t I think of this before?’”

Compared with bees, humans have a rather simplistic sex-determination process. In females, the two sex-determination chromosomes are the same, and in males the two chromosomes are different. The chromosome from the male determines the sex of the offspring. With bees, however, the combinations of complementary sex determination genes, or CSDs, determine the sex and the societal role of the bees.

One particular gene can have alleles – the “flavors” of genes. In humans, they dictate hair and eye color. In bees, they are responsible for creating females (worker bees), fertile males (that mate with the queen) or infertile males (diploid males, which serve no purpose).

The ‘Eureka’ moment came once Huang estimated the bees’ mating habits and the potential of CSD allele combinations. That’s when he understood why he couldn’t confirm the founder effect. Keeping the CSD mix diverse is one of the keys to maintaining a healthy hive, Huang said.

The island queens carry around 40 CSD alleles. Because each one mates with nearly 100 males – each also harboring around 40 alleles – the high number of healthy genetic combinations keeps the gene pool diverse. By using natural selection to create healthy offspring, the bees perpetuate a healthy colony.

In comparison, if the island bees adopted the breeding habits of fire ants, with queens mating with a single male, inbreeding could wreck the off-shore clades, distinct populations of bees. The devastating change would reduce the fitness of the hive, decreasing the female workforce, and lowering the number of mating males.

What would be left would be an unhealthy hive with higher numbers of diploid or infertile males, with the same alleles, Huang said.

By extending his research beyond Hainan Island, Huang found evidence that the island wasn’t an isolated case.

“We failed to find any clustering of the bees’ CSD alleles according to their geographical origin -- the Hainan and mainland bees did not form separate clades,” he said. “Previously published CSD sequences also failed to show any unique clade-forming in the Philippines and Malaysia.”

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MSU study: food and agriculture contributions to Michigan economy top $90 billion

Michigan’s food and agriculture business sector has emerged from the recession with flying colors. An updated Michigan State University (MSU) study on the impact of the food and agriculture supply chain shows that the industry contributes an estimated $91.4 billion to Michigan’s economy. That’s an increase of nearly 50 percent between 2004 and 2010.

Chris Peterson, director of the MSU Product Center, announced the findings from “The Economic Impact of Michigan’s Food and Agriculture System” during a Michigan Agriculture and Rural Development Commission meeting April 11 in Lansing. The study is based predominately on 2010 data—the latest available.

Though the largest dollar growth came from the wholesale and retail distribution portion of the supply chain, the largest percentage of growth came from farming. The farming line encompasses food, energy, horticultural crops, animal production and turf production.

“The impact of Michigan’s farms and the commodities they produce is 12 percent of the overall total, and their economic contribution has nearly doubled from less than $7 billion to more than $13 billion,” said Peterson, an MSU AgBioResearch scientist. “You’d be hard-pressed to find another business sector that has pulled through the recession with those kinds of numbers in just six years.”

Peterson attributes the growth to a substantial increase in the value of food and agricultural products throughout the world.

“The global population increase and the dramatic expansion of the middle class worldwide means that more people are consuming more food and, at the same time, pushes the food price higher,” he explained.

Keith Creagh, director of the Michigan Department of Agriculture and Rural Development (MDARD), said Michigan’s food and agriculture industry remains core to the state’s economic recovery and reinvention.

“As a $91.4 billion industry, it would rank 47th if it were on the list of Fortune 500 companies,” Creagh said. “Thanks to Michigan’s crop diversity—coupled with our fresh water access and business innovation—food and agriculture will be centric to Michigan’s economic reinvention and lay the foundation for regional economies. From having an educated talent bank to cultivating a fair regulatory platform, Michigan has worked hard to create an environment where businesses have an opportunity to grow.”

According to the report, Michigan has more than 73,000 full-time farmers and farm workers. That’s 12 percent of the 618,000 direct jobs in Michigan’s food and agriculture business sector. Food and agriculture account for 22 percent of all jobs in Michigan when direct, indirect and induced jobs are considered.

The total jobs line showed a downturn overall from 2004 to 2010, with most job losses coming from food wholesale and retail. Jobs in food processing and agricultural production rose more than 6 percent in the same time period.

“It’s not surprising that there were job losses in the service sector,” Peterson said. “Fewer people are eating out, which leads to fewer wait staff, cooks, restaurant hosts, etc. However, we’re seeing the numbers of new jobs created in food processing plants and on farms continue to increase.”

The study was first conducted in 2006 using 2004 data. Then, the value of the food and agriculture sector was determined to be $60.1 billion. An interim study in 2009 showed an increase in value to $71.3 billion. The newest study shows that the food and agriculture system is on a consistent growth trend.

That’s a surprise to Bill Knudson, product marketing economist with the MSU Product Center and the study’s lead technician.

“Unlike manufactured goods and tourism, food is a necessity, so we knew this sector had the potential to fare better than other industries in an economic downturn,” he said. “But even we were surprised to see the size of the increase despite the global recession.”

The full report and an executive summary are available at www.productcenter.msu.edu.

The MSU Product Center provides coordinated, universitywide assistance to help Michigan entrepreneurs develop and commercialize high-value, consumer responsive products and businesses in the agriculture, food, natural resources and bioeconomy sectors.

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Journal shines spotlight on long-term ecological research

For more than 20 years, Michigan State University has been a part of the Long-Term Ecological Research program (LTER), a National Science Foundation-funded project to conduct research on ecological issues that can last decades and span huge geographical areas.

In celebration of the LTER program, which has been in existence for nearly 30 years, six new papers relating to the importance of such long-term research were recently published in the scientific journal BioScience. MSU AgBioResearch scientists Phil Robertson and Doug Landis are among LTER researchers with articles published in the journal. There are more than 26 sites throughout the world, including the KBS LTER site at the MSU W.K. Kellogg Biological Station near Kalamazoo.

Robertson, who has led the KBS LTER for those 20-plus years, is the lead author of the first article in the BioScience series. His piece notes the success of the program in documenting and understanding environmental changes that are difficult to detect in short-term studies.

“As we move into an era where human decisions affect even the most remote ecosystems, we need more than ever to understand how decisions cause ecological change both planned and inadvertent,” said Robertson, a university distinguished professor of crop and soil sciences.  “Many of these changes take a long time to play out, and LTER helps us to understand their underlying origins and effects.”

Since 1988 — the year that KBS joined the LTER network — hundreds of scientists have visited this rural landscape in southwestern Michigan, where research is focused on agricultural ecosystems. They come to address the pressing agricultural challenge of how to provide the food and biofuel feedstocks needed by society while improving sustainability and minimizing negative environmental consequences.

Unlike most grant-funded research that spans a few years, LTER studies are often sustained over decades, documenting gradual changes and sudden surprises that often cannot be revealed by short-term studies.

“Long-term field experiments are critical for discovering the causes and consequences of environmental change,” said Landis, a professor in the MSU Department of Entomology. “Even in managed ecosystems such as Michigan field crops, we can miss the boat without a long-term perspective.”

MSU AgBioResearch Director Steve Pueppke said the long-term research conducted at the LTER provides an opportunity to understand the past and help forecast future environmental change.

“This network of long-term experiments taking place in climates from polar to tropical, from maritime to continental, and in ecosystems that range from Antarctic valleys to Michigan cropland, is crucial to solving many of the environmental problems facing society today,” Pueppke said.