Mississippi Agricultural and Forestry Experiment Station

Biochemistry, Molecular Biology, Entomology and Plant Pathology

Scientists in the Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology conducts research focused on topics of concern to agriculture in Mississippi, the Southern region and the nation. Biochemistry and Molecular Biology faculty work on projects with corn, cotton, rice, livestock, biofuels and fruits. Entomology and Plant Pathology faculty members conducts basic and applied research dealing with the systematics, biology and management of agricultural and forest pests. Faculty in both departments also work on projects associated with human health in environmental toxicology, pharmacology, and plant diseases.

Learn more at biochemistry.msstate.edu

 

A soldier in the fight

The black soldier fly, which turns agricultural waste into viable protein that can be used in feed for livestock such as chickens, may help fight food insecurity. John Schneider, Mississippi Agricultural and Forestry Experiment Station and professor of entomology in the Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, is evaluating how to integrate the insect into food production systems. According to Schneider, studies indicate that the insect is a high quality food source with no side effects. He hopes the research will help close the ecological loop, providing an efficient way to reduce agricultural waste and produce livestock feed.

Developing an antidote for nerve agents

The use of nerve agents in warfare has been a concern since World War II, but the only currently available antidotes act only after these weapons have damaged the nervous system. However, MSU researchers are working to develop an antidote that works before severe damage occurs. Toxicologist Howard Chambers and chemist Steven Gwaltney are developing an antidote that could protect victims from the usual signs of nerve agent poisoning: tremors, seizures, and respiratory collapse. Scientists in the College of Veterinary Medicine will test the experimental antidotes. They will use compounds similar to nerve agents—not actual chemical weapons—to safely test the antidotes, which are formulated to enhance the ability of a blood enzyme to degrade agents before they enter the nervous system. The antidote under development at MSU could also be used in cases of insecticide poisoning.

Developing a new antifungal drug

A MAFES researcher’s discovery of an agricultural phenomenon could lead to the development of a new antifungal compound that shows significant promise for treating serious fungal infections in people with compromised immune systems, such as those undergoing chemotherapy or those with HIV or AIDS. While studying crop reactions to disease-causing organisms, plant pathologist Shien Lu discovered a patch of soil in Mississippi that suppressed diseases. This finding led him to identify a new compound called “occidiofungin,” with broad antifungal properties. Occidiofungin has great potential as a crop fungicide or as a pharmaceutical product for humans and animals. Upcoming clinical evaluations will examine its effects on animal fungal infections and its performance in controlling plant disease. Lu works with other researchers, including scientists in the MSU College of Veterinary Medicine, to explore the potential of occidiofungin, define how it works, and determine whether it is safe for humans and animals.

Looking to nature for biomass solutions

Biochemist Ashli Brown gained national attention for a unique approach to natural biofuel production: the use of “panda poop.” More specifically, she discovered that microbes in panda feces are strong enough to efficiently break down woody material and other tough plants. These bacteria could tremendously cut production costs for alternative fuels and allow the use of plants other than food crops. One of the most expensive processes in making biofuels is the pretreatment, where sugar polymers in plants are chemically treated so they can be fermented and distilled to make ethanol. Enzymes in the bacteria speed up the break down of cellulose into simple sugars and thus offer a more energy-efficient way to turn materials such as switchgrass, corn stalks, and wood chips into biofuel.

Brown and fellow biochemist Darrell Sparks conducted a 14-month study of the giant pandas at the Memphis Zoo. While the initial focus of the study was to observe the overall health and nutrition of the pandas, they found several species of bacteria that break down cellulitic plant material that is generally difficult to digest. These microbes are similar to bacteria that help termites digest wood, but the panda-associated bacteria appear to be more efficient at breaking down plant materials and may work in a way that is better for biofuel manufacturing. So far, the scientists have identified 40 high-potential bacteria species in the pandas’ digestive tracts.

Controlling aflatoxin in corn

United States corn and peanut farmers lose about $200 million each year due to crop contamination with aflatoxin, a naturally occurring toxin produced by the mold fungi Aspergillus flavus and A. parasiticus. Delta R&E Center scientist Gabe Sciumbato and colleagues in the USDA Agricultural Research Service are evaluating an in-field approach to reduce amount of aflatoxin in corn. The scientists obtained A. flavus fungal strains that do not produce aflatoxin. The scientists innoculate cornfields with A. flavus fungal strains that do not produce aflatoxin. These atoxogenic fungi outcompete the resident toxogenic fungi—in essence, fighting a bad mold with a good one. Using non-aflatoxin fungi has the potential to protect much of the nation’s corn harvest.

Examining insects for nutrition and waste disposal

Imagine an insect that can eat nearly anything, control microbes, survive on water alone as an adult, and provide a good source of protein for animal feed. Entomologist John Schneider leads a team of scientists studying just such an insect: the black soldier fly. This insect could eliminate large amounts of agricultural waste while generating a valuable feed source. Black soldier fly larvae are 40–45 percent protein by dry weight. Harvested larvae can be dried and milled to create a high-protein meal for cattle, poultry, and fish consumption. These versatile, high-potential flies are not known disease carriers, do not bite or sting, and are not a nuisance species. Soldier fly larvae can eat almost anything—manure, cotton gin trash, and other agricultural by-products—without leaving behind any harmful fungi or microbial residue. With financial support from industry and visiting scholar Alfredo Llecha of Spain, MAFES researchers are designing a building with the optimum conditions for rearing black soldier flies.

Improving Turf Grass and Ornamentals

Associate research professor Maria Tomaso-Peterson knows a few things about disease-causing fungi, especially those that develop in grasses and ornamental crops. One problem she studies is spring dead spot in turf, with particular emphasis on determining why some plants develop a resistance to fungi. A key goal is figuring out how different cultivation methods can enhance disease management in Bermuda grasses planted in the South. Recently, Tomaso-Peterson showed that producers can help prevent Pythium fungi in poinsettias by using biofungicides, biological agents that fight fungi and other harmful microorganisms organically. Applying biofungicides will reduce the rate of conventional fungicides required, thus increasing producer profits and reducing the need for possibly harmful chemicals.

Cotton yields increase with new technology

Researchers at Mississippi State University have developed technology that uses reflected light to analyze the presence of certain nematodes in cotton fields so producers can increase profits. Since 2001, MAFES and MSU scientists have been developing a way to use remote sensing technology to battle reniform and root-knot nematodes, which are the No. 1 cotton pest in Mississippi, Alabama and Louisiana. In recent years, Mississippi cotton producers lost more profits from these nematode infestations than any other state, including a loss of 225,000 bales worth $87.8 million in 2006.

Compared to the nematode counts, the data collected through hyperspectral imaging was 75 to 100 percent accurate. The data was used to generate a field map showing areas of low, medium and high nematode populations. From that, a prescription map for applying different amounts of nematicide was created. For the producers, the yields were higher, which increases profits. Plus they saved money by applying only the amount of chemical required rather than blanketing their field with the amount needed to treat the highest population of nematodes found in their soil samples. The third benefit is to the environment, because site-specific applications reduce the amount of chemical used.

This research benefits not only Mississippi, but the entire Southeast, as producers in Alabama and Georgia routinely use the site-specific application method for treating their fields.

MSU professor finds pandas may aid biofuel production

MAFES scientists are looking to "panda poop," or microbes in panda excrement that breakdown woody materials, as a possible means to biofuel production. Scientists recently discovered that microbes in panda feces are strong enough to break down the toughest plant materials. Panda poop might help overcome one of the major challenges to producing biofuels: breaking down the raw plant materials used to make the fuels.

The findings have garnered national attention as the reproduction of these microbes could contribute to developing alternative fuels that don’t interfere with food crops and could also save a great deal of money. One of the most expensive processes in making biofuels is the pretreatment, where sugar polymers are chemically treated so that they can be used to make ethanol or oil. If you can insert a microbe that does that naturally and efficiently, production costs for alternative fuels would be cut tremendously.

MSU research benefits poinsettia producers

Researchers at Mississippi State University have found a cost-effective and environmentally friendly strategy for fighting one of the most serious soil-borne diseases in poinsettia production. Pythium stem and root rot is a common problem in poinsettia production because the fungus thrives in cool, saturated and poorly drained soils. MAFES researchers found a way to use organic methods and fewer fungicides to successfully fight this pathogen.

Pythium is a widespread fungus. Plants are cross-contaminated by splashing water or soil from pot to pot. In nursery management, producers treat the plants when they transplant cuttings to the pot. Once the disease is established, it’s too late to treat, so growers have to use a fungicide early in the season to make sure they have a healthy crop. The standard conventional fungicide is effective but expensive, and there is a high risk that the fungus will become resistant to the chemical.

Managing resistance to important fungicides is a key component of a disease management program. One of the strategies MAFES scientists are researching is integrating biofungicides. Biological agents are not conventional fungicides or chemicals, but organic methods of fighting fungi or other harmful microorganisms. The study found that a reduced rate of the conventional fungicide, when used with a biological agent, resulted in plants that didn’t rot and had similar growth to the label rate of conventional fungicides. This is beneficial to growers because it reduces their impact on the environment. It also reduces the risk of the pathogens adapting to the fungicides and becoming resistant and may save producers money by reducing the amount of fungicide they use.

High-protein insect studied at MSU

Imagine an insect that can eat nearly anything, control microbes, live off of water alone in the adult stage, and be a good source of protein for animal feed. The black soldier fly is real, not science fiction, and it has researchers at Mississippi State University abuzz with excitement. MAFES scientists are studying the black soldier fly as a potential solution to dealing with large amounts of waste while also generating a feed product. Black soldier flies are 40 to 45 percent protein by dry weight. Theoretically, one metric ton can be produced per day in the space of a medium-sized house, and used as a feed product.

Harvested larvae can be dried and milled to create a high-protein meal for livestock, poultry and aquaculture consumption. Due to their high oil content, black soldier fly larvae may even be useful for biofuel production. They’re not a known disease carrier, they don’t bite or sting, and they’re not a nuisance. They’re a versatile species with huge potential.

Black soldier fly larvae will eat almost anything—manure, carcasses—without any remaining harmful fungi or microbial residue. These insects require no special diet, so they can be fed nearly any kind of agricultural byproducts or waste.

Corn researchers develop in-field aflatoxin approach

MAFES scientists are researching new ways to reduce aflatoxin in infected corn. Corn is one of the state’s leading row crops, but it is susceptible to aflatoxin, a fungus that can reduce profits and hurt marketability.

Aflatoxins are naturally occurring chemicals produced by the fungi Aspergillus flavus and A. parasiticus. The fungi appear as yellow-green or gray-green molds on corn in the field or in storage. Scientists are applying granules of Aspergillus flavus that do not produce aflatoxin but do compete with the native Aspergillus flavus. In essence, they are using a good fungus to fight a bad one. Aflatoxin levels are not normally high in corn, but Mississippi’s hot, humid climate encourages the growth of the fungus that produces the toxin. Heat, drought, high humidity, insect infestation and anything else that stresses the crop favor fungal growth.

Aflatoxin can build up in crops such as corn, cotton, peanuts and tree nuts. Aspergillus infects corn by invading through corn silks or through insect damage to kernels or ears. Using non-aflatoxin-producing A. flavus strains has the potential to protect much of the state’s corn harvest.

MSU working to increase endangered toad numbers

Plastic storage crates in a sunny lab at Mississippi State University are the new homes of 52 endangered Boreal toads, native to the Colorado Rockies. Boreal toad numbers have dwindled to dangerous levels in recent years, and MAFES scientists have partnered with the Memphis Zoo to find a way to increase the population.

We’re trying to optimize the reproduction protocols for these toads. We want to get the toads to reproduce in captivity so the young can be raised and released to the wild. In Colorado, they usually hibernate naturally from November to summer, and this is believed to be a major trigger of their reproductive cycle.

Scientists are trying to figure out what hormones to use to get the Boreal toads to reproduce in captivity without hibernation.

Identifying Destructive Invaders

Exotic insect species enter the United States through multiple routes, such as on wood shipping pallets, plant materials, and imported fruits and vegetables. The U.S. government sets trade restrictions to help prevent the introduction of nonnative pests, and its inspectors work at all borders to search for and confiscate materials carrying these insects. Some hidden pests do make it past inspection and move into U.S. crops. Once established, these pests can damage crops and native plant species, ultimately causing severe economic damage. Quick identification of invasive species is crucial to stopping their spread. The Mississippi Entomological Museum was recently designated as the Eastern Region Identification Center for the USDA’s Animal and Plant Health Inspection Service.

Muscadine Juice Prevents E. Coli

Finding natural antimicrobial compounds in fruit to enhance the safety of its juice is of great interest to the beverage industry because Escherichia coli, which causes foodborne illness, can survive in acidic environments for long periods. Muscadine grape is indigenous to the Southeast and contains a large variety of antioxidant phytonutrients. MAFES scientists found that red muscadine juice has natural antibacterial substances and suggest that these can be used as active antimicrobial ingredients against E. coli in nonalcoholic beverages.

Safer Horse Transportation

There has been little research to measure the heat conditions in horse trailers during transport. MAFES scientists recently measured several temperature variables in a fully enclosed four-horse, ant-load trailer with and without animals. Scientists found that trailer temperatures during transport exceeded those recommended for animal housing, although the thermal environment was affected by vehicle speed, vent configuration and presence of animals. They found that temperature increased significantly in transport during relatively mild weather, which indicates that horses could suffer from heat stress during warmer weather. These results show the importance of closely monitoring heat conditions in trailers used to transport horses.

Asian Beetle Threatens Coastal Trees

A beetle that made its presence known in Mississippi this summer is threatening the extinction of red bay trees in the state. The beetle is the red bay ambrosia beetle, a dark brown insect about half the size of an uncooked grain of rice. It spreads the pathogen that causes Laurel wilt disease in many tree species, including Mississippi’s red bay and sassafras trees. MAFES scientists are trying to determine how the beetle got into Mississippi so it can be stopped.

Luminating Infections in Pregnant Mares

Infections are the leading cause of abortion, stillbirth and preterm delivery in mares. MAFES scientists have developed a new approach to understanding the infection process in pregnant mares by using biophotonic imaging and modified bacteria with luminescent characteristics. In other words, the technique allows researchers to capture real-time pictures of glowing bacteria as they spread through a mare’s body. The method allows scientists to track pathogens in a minimally invasive procedure.

MSU Research Takes the Bite Out of Mosquitoes

Since 1999, the United States has had 30,062 cases of West Nile virus, according to the Centers for Disease Control and Prevention. Of these cases, 1,247 were fatal. Mississippi has had 842 cases, including 48 fatalities.

Like malaria, West Nile virus is spread by mosquitoes. West Nile virus and malaria cases together make mosquitoes the world’s No. 1 vector for disease transmission. After Hurricane Katrina, coastal states became prime mosquito-breeding grounds, creating the possibility for a spike in West Nile cases and associated deaths.

The U.S. Congress earmarked a sizeable grant to enhance mosquito control in states most vulnerable to post-Katrina mosquito infestation. The Mississippi Department of Health (MDH) administered the funds to the 49 counties declared disaster areas after Katrina.

Before distributing any money, the MDH held mosquito- education workshops throughout the state. The agency conducted pre- and postgrant surveys designed to gauge practices, knowledge and attitudes of local personnel in mosquito- control programs before and after disbursement of funds.

Postdoctoral associate and veterinarian Kristine Edwards and associate Extension professor Jerome Goddard, both in entomology and plant pathology, conducted research and workshops based on survey responses.

"The workshops stressed that mosquito- control efforts should follow a hierarchy, and the use of spray trucks should be a low-priority option," said Edwards.

However, before 2007, many Mississippi communities had their mosquito control priorities reversed, Edwards said.

"You usually see the trucks go first, but all that does is kill adult mosquitoes. By then it’s usually too late," Edwards said.

Educating the general public on how to protect themselves has always been the most important way to control mosquitoes. The next priority is source reduction, which involves removing breeding grounds such as standing water in old tires and other containers. Destroying mosquito larvae in standing water comes next.

The final solution, which Edwards said is too often the first approach taken, is killing adult insects. Slow-rolling trucks equipped with $8,000 bug sprayers rumbling down neighborhood streets are a common sight in this process.

The study provided guidelines for cities to combat the disease-carrying pest. Steps include first surveying to find which ditches have mosquitoes, and then spraying larvicides to kill larvae in the standing water. The final tactic is spraying adulticides to kill mature mosquitoes.

The guidelines also recommend adult mosquito trapping, which captures seven to 10 mosquitoes on a typical night. When the count swells to 50 to 100 specimens, usually a week after a good rain, it is time to spray. Edwards said simple tactics like surveying and trapping can save local governments time and effort.

Toxin-free Castor Would Be Major Help to Industry

Castor oil is the highly desirable, plentiful product of castor beans. The oil is used to produce everything from cosmetics and paints to jet aircraft lubricants and certain plastics. The thick oil makes up 60 percent of the seed’s weight. By comparison, high-oil corn or canola only produce about 25 percent oil by weight. Ninety percent of the oil is ricinoleic acid, a fatty acid found in large quantities only in castor oil. This acid has many industrial applications.

MAFES scientist are trying to make it possible to grow the plant safely for commercial oil production in Mississippi. Castor seed meal, not the oil, contains ricin, a toxic protein that can become fatal if untreated in the body.

To make castor a commercially viable U.S. crop, scientists are trying to discover a way to genetically modify the plant so that either the gene that produces the toxin is no longer expressed or the toxin is no longer produced.

One of the challenges is that castor resists being transformed. The genetic modification process involves inserting a fragment of DNA foreign to the plant into the genetic code, where it must be accepted and become active.

Everything from cotton to corn and soybeans has been genetically modified, but castor is much more difficult. The castor cells can be transformed, but you can’t get whole plants to grow from the cells.