Biochemistry, Molecular Biology, Entomology and Plant Pathology

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. Read More

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. Read More

While ambrosia beetles are believed to have been introduced into the U.S. from Asia in the early 2000s, they were not known to cause damage to healthy trees until the Laurel wilt epidemic. Laurel wilt can readily kill any plant in the family Lauraceae, which is more than a dozen species including swampbay, avocado, sassafras, and more. If Laurel wilt continues at its present pace, consumers might have to say goodbye to bay leaf, produced by the swampbay; guacamole, produced by avocado trees; and spicy gumbo, which contains sassafras. MAFES researchers are steadily working to understand both the disease and the beetles that carry it, having already uncovered that the beetles carrying Laurel wilt are all genetically identical. They have also produced a spatial model that revised the prediction of the disease's spread in hopes of finding a solution to save the vulnerable trees in the Southeast and beyond. Read more

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. Read More

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. Read More

Butterflies are the oft-forgotten pollinators of Mississippi, but MAFES researchers are striving to change that. They have begun creating a massive inventory of the butterflies in the Sam D. Hamilton Noxubee National Wildlife Refuge. By making note of butterfly species, populations, and habitats, researchers can shape a fuller idea of the best management practices to keep the Refuge's butterflies thriving. Read more

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. Read More

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. Read More

A common concern among farmers first exploring the option of cover crops is the pests that use the cover crop as a "Green Bridge" onto the cash crop. Researchers at MAFES sought to determine the influence of winter annual cover crops and insect management strategies on surface and subsurface insect pests in soybeans. After conducting numerous variations of several management practices, they found neonicotinoid seed treatments and early termination of cover crops were sufficient in controlling pests and did not observe a "Green Bridge" phenomenon. Read more

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.

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. Read More

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.

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. Read More

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. Read More

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. 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 is killing adult insects. 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. Read More

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. Read More

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.

As a molecular biologist, Dr. Florencia Meyer, a scientist in the Mississippi Agricultural and Forestry Experiment Station, hopes to unlock molecular secrets about the microbes that contribute to the cause of bovine respiratory disease. Bovine respiratory disease, or BRD, costs the cattle industry an estimated one billion dollars annually. The disease is usually caused by a combination of factors including stress, a viral infection, and bacteria present in the animal. Vaccines are used to prevent the disease and treatment options include antibiotics and stress management. Despite these options, however, BRD remains the number one health problem for the cattle industry, causing widespread illness, death, and production losses. While Meyer is currently studying three microbes at once, two of her recent publications centered on foundational research she has conducted on BoHV-1 alone. Most recently, the team ascribed a potential new gene for BoHV-1. "The project's findings will provide valuable information for the development of novel vaccine or pharmaceutical formulations that can help reduce the incidence of BRD and promote animal health, thus helping to ensure the safety and sustainability of the U.S. beef industry," she said. While the search for more answers continues, Meyer's research seeks to help establish better understanding of the multiple factors that affect this disease. Read more

Taproot decline is the seventh-leading cause of yield loss for soybean producers across Mississippi, and Xylaria, the novel fungal pathogen behind the disease, has become a top research priority for a group of MAFES researchers. As the focus of an ongoing six-year study into the pathogen, these scientists are now striving to understand the soybean's immune response to Xylaria infection. While taproot decline is devastating to soybean producers, this study offers hope, as the immune response suggests that certain microbes in the soil could prevent infection. Fifteen of the more than 300 bacterial varieties tested for Xylaria resistance have shown promising results, and though the testing on which is best suited for large scale application continues, the researchers hope to one day have a microbial soil treatment to stop this disease. Read more

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.

One of the most consistent challenges producers face is yield loss from insects. Over the years, strides have been made to develop cultivars, specifically of cotton and corn, that are naturally resistant to insects, thanks to a naturally occurring soil bacterium, Bacillus thuringiensis, or Bt, that is detrimental to common pests. Bt crops are created by inserting genes into the plant's genome, causing the plant to produce proteins toxic to certain insects. In modern agronomic insect pest management, Bt crops/technologies are some of the most effective tools. MAFES scientists at the Delta Research and Extension Center have been hard at work evaluating the field performance of these Bt crops including treatment thresholds for these crops when or if foliar insecticide applications are needed, and performance-issue events such as unexpected damage or insect survival. The study has shown some pests are becoming resistant to one of the detrimental proteins Bt crops produce, opening a new avenue of research to help producers mitigate insect pressure in the future. Read more

The most common garden vegetable is also a staple in research laboratories at Mississippi State. From herbicide tolerance to gene modification, tomatoes are being studied to help farmers grow the popular fruit with fewer losses or injuries to the plants. Dr. Sorina Popescu, MAFES assistant professor in biochemistry, molecular biology, entomology and plant pathology, is working to understand how tomato plants respond to pathogens at the molecular level, and editing the plants using CRISPR (clustered regularly interspaced short palindromic repeats) technology. Popescu explained that the technology allows her to silence a gene expression or make it louder, which affects the plant's response. The technique is promising, she said, because you don’t bring anything new into the plant or take anything away. The pathogen Popescu is studying is called Pseudomonas syringae. It can easily wipe out an entire tomato crop if it infects the garden.The pathogen causes brown-black leaf spots and specks on green and red fruit. The pathogen causes stunting and yield loss, particularly if young plants are infected. Most pathogens have effectors that act in very similar ways. By studying tomatoes and Pseudomonas syringae, Popescu believes the findings can be extended to other vegetable crops to make them less susceptible to pathogens. Other tomato research happening at Mississippi State, though, may show noticeable improvements in the field more quickly. Dr. Paul Tseng, assistant MAFES professor in plant and soil sciences, is working on two research projects to get rid of the weeds growing in tomato crops. One of Tseng's research projects is to find herbicide-tolerant tomatoes that won't be affected by herbicide drift. His research started with 120 different varieties of tomatoes. So far, he has found 10 to 20 varieties that are tolerant to different herbicides. These varieties, though, are not necessarily commercially-produced tomatoes, and don't have the agronomic qualities like high yield and large fruit size that growers want. Tseng is also fighting the weeds directly through the allopathic traits in tomatoes. Allelopathy is the chemical inhibition of one plant by another, due to a release into the environment of substances acting as growth inhibitors. Allopathic tomatoes would release chemicals into the soil that interact with the roots and weeds and kill them. Both studies will help growers continue to provide one of summer's favorite fruits: red, ripe tomatoes. Read More

In the midSouth, early-season pest management is a significant challenge to farmers. For insects, relatively mild winters combined with long, productive growing seasons create an almost perfect environment for their propagation. It is not unusual to see a variety of pest species coexisting at high levels in many fields. Neonicotinoids (also known as neonics) are systemic insecticides that are chemically similar to nicotine. The insecticide is absorbed by the plant and circulates through the plant’s tissues, killing the insects that feed on them. Unlike contact insecticides, which remain on the surface of the treated foliage, systemic insecticides are taken up by the plant and transported to other plant tissues that may include leaves, flowers, roots, stems, pollen, and nectar depending on the method of application. A decline in managed pollinators over the last decade led researchers to investigate if neonicotinoids were a contributing factor. It was deteremined that the risk to pollinators from neonicotinoids is so small; there essentially is no risk in the Midsouth. Read More

Drs. Florencia Meyer, associate professor, Dr. Carrie Vance, associate research professor, both in the Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology and scientists in the Mississippi Agricultural and Forestry Experiment Station, have teamed up with Dr. Amelia Woolums, professor in the Department of Pathobiology and Population Medicine in the College of Veterinary Medicine, to research ways to better diagnose bovine respiratory disease (BRD). BRD is the most significant disease impacting the American feedlot industry and expands as a global problem. The team used Near Infrared Spectroscopy (NIRS) to find a better way to diagnose BRD. The current protocol is to prophylactically treat animals exhibiting any BRD symptoms, whether they have the disease or not. By having a NIRS device that tests animals quickly and accurately, this would significantly reduce the amount of antibiotics that are used on animals that do not need them. So, researchers are developing a diagnostic strategy for the early detection and treatment of animals developing BRD. This will be a means to analyze a global set of health parameters in a rapid assay that can determine the specific health status of animals at risk of developing BRD. Modeling what the disease profile looks like makes identifying BRD more like a fingerprint than a single assay. A significant percent of cattle goes unidentified and untreated with BRD, which is why better diagnostic tools need to be developed. The current model the team has created has an overall accuracy of 83.3%, with a sensitivity of 79.2 %, and a specificity of 87.5%, which is much higher than the current BRD diagnosis. The work was funded by the Mississippi Agricultural and Forestry Experiment Station’s Special Research Initiative and the USDA-ARS 58-6402-018 Biophotonics Initiative. Read more.

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. Read More

Currently, the Magnolia State is experiencing its worst pine beetle outbreak in more than 30 years with more than 4,000 spots throughout the state's forests infested with the southern pine beetle. And the problem extends far beyond Mississippi to places like Arizona and Honduras. Dr. John Riggins, associate professor in the Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, explained that pine beetle outbreaks can potentially be both a symptom and cause of climate change. "As the climate becomes more variable, we tend to have more pine beetle outbreaks, which in turn, could cause entire forests to shift from carbon sinks to carbon sources," Riggins said. At sites in Mississippi, Arizona, and Honduras, researchers are collecting data on felled trees in forests naturally infested with pine beetles alongside felled healthy trees. They have caged individual wood sections in different ways so they can study the impact of above- and below-ground invertebrate, fungi, and microbes in isolated settings. They will then measure woody decomposition at year one and year two and determine how each species contributes to the breakdown of wood. Additionally, they are measuring the carbon and nitrogen in and around the tree, including the carbon that is being released into the atmosphere from the wood and the soils. Researchers hope the sites will show them the prevalence of the interspecies interaction across different climates between different subspecies of pine beetles and termites. Read more

In the world of turf science, mysterious brown spots provide a peek at the multitude of bacteria and fungi that live within our lawns. Dr. Maria Tomaso-Peterson, a MAFES research professor in biochemistry, molecular biology, plant pathology and entomology, recently classified Culvaria malina, a strain of fungus common in turfgrass, which had previously gone unclassified. While fungi identification might seem straight-forward, figuring out which fungus is causing a symptom can be difficult; every plant has a variety of fungi living on it and many are benign. In order to discover which is causing the problem, researchers isolate one fungus at a time. The fungus is easily recognized by the distinct black eye spot lesion it causes on the leaf itself. Turf fungus is not the only mystery Tomaso-Peterson solves. There's a soybean disease coined the 'mystery disease' that has been out in the fields for 10 to 15 years. Scientists have only recently started looking at it. The diseased plants were brought to the lab and a fungus was isolated, identified and found to belong to a genus of woodrot fungi that generally isn't parasitic to plants. The soybean disease has been named 'taproot decline,' and scientists are currently collecting plants from all over Mississippi in order to get an idea of what the diversity is across the state. By identifying the pathogen and then classifying fungi according to genus-species, scientists are able to create a body of work, recording data such as the conditions it is found under, the symptoms it causes, and the biology behind it. It also allows them to get an idea of how prevalent it is in plants within a region, and what steps might be taken to prevent plant diseases. Read More

Biomedical, physiological, and agricultural experts across Mississippi are joining together to protect one very important creature: the bee. Worker bees everywhere are being plagued by insistent varroa mites, and MAFES researchers are bringing medical technology intended for humans into the hive to administer a more effective, longer-lasting method for fighting the varroa. Researchers hope the technology will provide a more effective way to eradicate the honeybee's biggest threat. Read more