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MAES Discoveries Upend Traditional Thinking about How Plants Make Certain Compounds

Rob LastAn MAES plant scientist helped identify two new genes and two new enzymes in tomato plants; those findings led the research team to discover that the plants were making monoterpenes, compounds that help give tomato leaves their distinctive smell, in a way that flies in the face of accepted thought.

On the basis of years of research, scientists thought that plants always used a specific compound, geranyl diphosphate, to make monoterpenes. But MAES biochemistry and molecular biology scientist Rob Last and postdoctoral researcher Anthony Schilmiller were part of the team that found that tomato plants use a different compound, neryl diphosphate, as the substrate for making monoterpenes. The difference is subtle, but the discovery will change the way terpene research is done. The research was published in the May 25 issue of the Proceedings of the National Academy of Sciences.

"Essentially, this work subverts the dominant paradigm about an important and widespread pathway in plants," Last explained. "For years it was known that monoterpenes are made in a specific way. But there were cases where that pathway likely wasn't involved, given the kinds of compounds found in specific plants. We showed that in tomato trichomes [small hair cells located mainly on the plant's leaves and stems], the established pathway is wrong. In the tomato trichome, two enzymes work together to make the monoterpenes in a previously unsuspected way."

The two newly identified genes, neryl diphosphate synthase 1 (NDPS1) and phellandrene synthase 1 (PHS1), cause the tomato plant to make the new enzymes that produce the monoterpenes.

As the team was sequencing the DNA of tomato trichomes, Schilmiller and Eran Pichersky, of the University of Michigan, noticed that there were many sequences from genes that weren't supposed to be involved in monoterpene production. Because the sequences were found so frequently, they hypothesized the genes must be making high levels of compounds in the trichome.

"We had to think outside the box to figure out what the function of NDPS1 and PHS1 were," Schilmiller said. "Our colleagues at the University of Michigan, Eran Pichersky and Ines Schauvinhold, were instrumental in coming up with theories and running the assays."

Terpenes are the largest class of molecules made by plants -- tens of thousands of terpenes have been identified. Some of the known functions of terpenes include attracting pollinators, repelling pests and protecting the plant from diseases, as well as giving many plants their smell and taste. The aroma of many plants, such as mint and basil, come from terpenes.

These new discoveries will allow other scientists to look for similar genes in other plants and perhaps discover new enzymes that make monoterpenes, which could lead to new ways to protect plants from pests.

Other co-authors from MSU are Amanda Charbonneau, biochemistry and molecular biology research assistant; and Matthew Larson and Curtis Wilkerson, of the bioinformatics core of the Research Technology Support Facility; from U-M are Adam Schmidt and Richard Xu.

This research is funded by the National Science Foundation.

Following Biosecurity Steps Help Ensure Healthy Swine

Barb StrawAs media coverage for the H1N1 influenza virus (previously called "swine flu") continues to wax and wane, many wonder what the connection is to pigs. The origin of the virus is still being investigated, but MAES large animal clinical scientist Barb Straw, a swine veterinarian who specializes in disease management, said there is no sign of the virus in swine herds in the United States -- and she credits strict biosecurity protocols for keeping H1N1 out of swine populations.

"There has been much public interest and concern about the new H1N1 influenza virus," Straw said. "The primary concern remains human to human transfer, but people with pigs should also be concerned about transferring the virus from human to animal."

Straw said all pig owners, including those with 4-H swine projects and backyard breeders, should take extra precautions to ensure that this new flu strain doesn't infect their pigs.

"Owners of pigs that are involved in shows and fairs have a particularly difficult challenge in guarding the health of their pigs," she said. "To protect the health of their own pigs and the health of the entire pork industry, they should practice as many of the 10 steps for biosecurity as possible."

The 10 steps for biosecurity on swine farms are:

  1. Quarantine all incoming stock and purchase pigs only from high health herds whose health status is compatible with that of your herd. New feeder pigs should be quarantined a minimum of 21 days, and new breeding stock, a minimum of 60 days.
  2. Provide clean boots and coveralls for all employees and visitors to your herd, and do not allow any employee or visitor showing influenza symptoms access to your herd.
  3. All animal caretakers on the farm should change into clean boots and coveralls upon entering each barn. Clean footbaths may be appropriate within a barn for different rooms.
  4. Minimize the entry of equipment and supplies into the pig barn. Take appropriate precautions such as disinfecting any equipment entering or reentering your farm.
  5. Prevent the access of wild animals (rodents and birds) or pets (dogs and cats) to pigs. Use screens in windows, air inlets, doors, etc.
  6. Restrict entry to essential personnel. Only animal caretakers and visitors wearing clean clothes and boots should be allowed to work with pigs.
  7. Provide shower facilities for visitors or a place to change into clean clothes.
  8. If sows are bred using artificial insemination, purchase semen from a genetics supplier who routinely tests for PRRS virus and other infectious agents.
  9. Ensure that feed and water sources are clean and free from infectious agents.
  10. Review your biosecurity plan and herd health program, including vaccination protocols, with your veterinarian on a regular basis.

Straw said large swine farms have an advantage in developing biosecurity protocols because they can strictly limit the number of people who come in contact with animals.

"Most large hog farms have already adopted all 10 of the biosecurity points, and they should take extra precautionary biosecurity measures with employees," Straw said. "Any employee who is showing symptoms of influenza infection should not be allowed to work with pigs until he/she is fully recovered."

Straw said that those who exhibit pigs in fairs and other shows should exercise added caution.

"Implementing any one of these suggestions will reduce the risk of disease entry and each additional step that's implemented will further reduce biosecurity risks," she said. "Participating in these events and then allowing the animals to return home increases the risk of spreading infectious disease. They should be treated as potentially infected animals."

Straw said show pigs that return home should be isolated from other pigs for at least 21 days. The quarantine facilities should be as far from the regular herd as possible, and the person providing daily care should change into clean clothes and boots before working with other pigs on the farm.

"There may be instances when state and fair officials are forced to change fair and show schedules to reduce the risk of disease transfer," she said. "In these rare occasions, exhibitors and their families must remember that it is important to maintain the health and safety of the nation’s swine herd."

Research Finds Southwestern Michigan Abuzz With Native Bee Species

Bee in flowerHow many kinds of bees can the average person name? Most folks throw in the towel after spelling, quilting, honey and bumble. Julianna Tuell, postdoctoral researcher who works with MAES entomology scientist Rufus Isaacs, can name a far greater number, but even she was surprised at what she found in the blueberry fields of southwestern Michigan.

As is the case for all horticultural crops, pollination is a critical step in blueberry production. Typically, domesticated honeybees are put on the job. Growers rent hives that are placed near fields, giving the insects access to the flowers from which they gather nectar and spread pollen from blossom to blossom, fertilizing the year's crop.

Blueberry growers have been concerned about the loss of wild honeybee colonies, which made them more dependent on rented colonies, and wanted to learn more about what other bees help pollinate their crop.

"They were concerned that honeybees weren't interested in some cultivars, and they wanted to know what other options there were," Tuell said.

To help answer the questions, she led a research team that collected, counted and categorized bees found in blueberry fields for 3 years on 15 southwestern Michigan farms. The scientists knew they would find native pollinators in the fields they studied because blueberries are native to North America. What they didn’t expect was the sheer number of bee species buzzing in the blueberry blossoms.

"We found 112 species during blueberry bloom, and 166 species overall," Tuell said. "They aren't all visiting blueberries, but at least half of them are contributing to pollination. There's a really wide diversity of bees across the season, with some that provide pollination during bloom and are also active later in the season."

The team found seven bee species that had never been found as far north as Michigan. These findings, published in the Annals of the Entomological Society of America, describe a more diverse ecosystem in managed blueberry fields than scientists had imagined and also mean that growers may have more pollination options than they thought.

"If you have a small field, you're likely to have a large number of these native bees that can provide a portion of the pollination work," Tuell said. "In large fields, growers are more dependent on honeybees because there isn't the density of native bees to do the pollination."

Native bees are active in the fields before, during and after blueberry bushes bloom. Farmers who time pesticide applications to avoid flowering and who don't spray during the day or when it’s windy can help these bees survive and be around for the next season.

Tuell and Isaacs are using the research results to help growers time spray applications so natural pollinators aren't affected.

"This research fits with the MSU Extension programming we’ve done to talk to blueberry growers about conservation strategies they might implement to make their fields more sustainable for native bees," Isaacs said. "We call it the closing of the circle. We got the input from the growers, we did the research, and then the results go back to the growers through workshops and a bulletin to put the information into their hands."

Besides the MAES, the research is funded by Project GREEEN (Generating Research and Extension to meet Economic and Environmental Needs), the plant industry initiative at MSU; MBG Marketing; and a C.S. Mott predoctoral fellowship in sustainable agriculture.

Mark Your Calendar for 30th Ag Expo, July 21-23 at MSU

Ag Expo logoAg Expo, Michigan’s largest outdoor farm show, returns to the Michigan State University campus July 21-23 for its 30th anniversary run, bringing a variety of educational and commercial activities and exhibits to the state's agricultural community as well as homeowners, families and anyone who wants to know more about the state's second-largest industry.

New to this year's show is "Profitable Environmental Options for Livestock Producers," a one-day (July 21) series of demonstrations at the MSU Beef Cattle Research Center. MSU experts will discuss feeding sites, feeders and bunker silos, watering systems, cattle handling and pasture seeding options.

Another new feature for 2009 will be on-site seed plots from commercial seed companies. Visitors will be able to talk with seed company reps while looking at examples of the companies’ corn, soybean and wheat hybrids.

Also on the Ag Expo grounds, visitors can take part in ride-and-drive demonstrations of skid steers, zero-turn mowers, tractor and wheel loaders, and draft horses. They can also take in lawn tractor (July 21) and antique tractor (July 22) pulls and watch the state FFA tractor driving contest (July 21).

The MSU College of Agriculture and Natural Resources (CANR) will once again present a tent full of "Family Futures" with education and activities for residents of all ages. The United Dairy Industry of Michigan will present a daily recipe demonstration in the tent at 11:45 a.m., and the MSU Dairy Store will offer free ice cream while accepting donations to support CANR scholarships.

"We've got a great mix of educational activities, ride-and-drive demonstrations and informational presentations planned for this year's show," said Ruth Hohl Borger, Ag Expo director. "Whether you manage 1,000 acres or mow a half-acre lawn, you’re guaranteed to learn something new at Ag Expo."

Ag Expo features commercial farm equipment from throughout the Midwest and several Canadian provinces on the 35-acre main exhibition site and the 40-acre field demonstration area, as well as educational exhibits from several MSU colleges and departments.

The event runs from 9 a.m. to 5 p.m. July 21 and 22, and 9 a.m. to 3 p.m. July 23. Admission to the grounds and parking at Farm Lane and Mt. Hope Road are free. Because of the construction on Farm Lane, the Ag Expo parking area and grounds will be accessible only from Mt. Hope Road.

For more information about Ag Expo, call 800-366-7055 or visit www.agexpo.msu.edu.

Ag Expo is sponsored by the MSU College of Agriculture and Natural Resources.

MAES Field Days and Special Events in June and July

June 2009

July 2009

Last Updated: May 28, 2009
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