California Fruit and Vegetable

Tag: Agricultural Research Service

  • The Antimicrobial Benefits of Mushrooms

    Scientists with the Agricultural Research Service (ARS) are examining the antimicrobial properties of mushroom extracts. Their goal: make food crops safer throughout the production process, from farm to fork – and beyond – including the ability to mitigate chronic human health conditions.

    Petri dish containing the fungus Aspergillus flavus. This common fungus is a concern because it produces carcinogenic aflatoxins that may contaminate certain foods and cause aspergillosis, an invasive fungal disease. (Photo by Peggy Greb)

    Mushrooms are a classic example of a two-sided coin. On one side, mushrooms are a valuable source of food and income around the world and are known to have pharmaceutical qualities. On the other, nearly 7,500 cases of mushroom poisoning (over 700 serious cases and 52 deaths) occur each year in the United States alone.

    Now, researchers are pitting the good properties of mushrooms against the bad.

    “Edible mushrooms [are] a source of bioactive compounds, and certain medicinal mushrooms have emerged as beneficial ingredients of dietary supplements,” said Jong H. Kim, molecular biologist at the ARS Foodborne Toxin Detection and Prevention Research unit in Albany, CA.

    Kim is the primary author of a paper on how medicinal mushrooms contribute to food safety.

    The role of mushrooms in food safety begins in the farmer’s field. According to Kim, pinecone cap mushrooms, which are a type of fungi, provide the main ingredient in the fight against a worldwide carcinogenic fungus – Aspergillus flavus.

    A. flavus produces aflatoxins, some of the most dangerous mycotoxins that widely contaminate many major crops, such as corn, tree nuts, and peanuts. People who eat a large amount of food contaminated with aflatoxins – or products derived from animals that have eaten it – are at higher risk for some adverse health conditions, including liver cancer and stunting in children.

    “Many antimicrobial agents have been developed from mushroom ingredients for crop protection, [including] the natural fungicide strobilurin,” Kim said. “Strobilurins [are] one of the most important classes of agricultural fungicide.”

    When farmers use strobilurins, the compound inhibits A. flavus growth by interrupting its ability to breathe. Stopping A. flavus in the field reduces the amount of aflatoxins that manufacturers must contend with during food processing and packaging.

    “[We] found that a component of the mushroom Taiwanofungus camphoratus (Tc) could be developed as a food ingredient having antimicrobial potential, thus inhibiting the growth of fungi and bacteria in foods,” Kim said. “Tc lowers the contamination rate of toxin-producing or heat-tolerant fungi that escape the food sanitation process. The application of Tc in the food industry will promote food safety, which is vital for the health of consumers.” – By Scott Elliott, USDA-ARS Office of Communications

  • Breeding a Better Potato for a Better Potato Chip

    Photo courtesy of Potatoes USA.

    Potato chips are America’s classic snack: crunchy, salty, greasy and tasting of potato or flavored with sour cream, vinegar, BBQ, maple bacon or Cajun dill. It shouldn’t be a surprise that Americans eat more potato chips than any other nation; more than four pounds a person a year, according to Potatoes USA. About 22 percent of the U.S. potato crop—nearly 7,500 million pounds annually—are made into chips. Consumers spend more than $7 billion dollars buying potato chips at retailers. And USDA’s Agricultural Research Service helps ensure that the country always has the perfect potato for frying into chips.

    ARS’ potato breeding program has already produced some major winners in the potato chip category. One is Atlantic, a variety ARS developed and released in 1976, that remains the number two chipping variety in the United States.

    But potato producers have been ready for an Atlantic replacement for years. Atlantic is vulnerable to internal heat necrosis, where darker spots or flecks form in the flesh of the potato particularly in sandy soils during warm, dry seasons. It is also susceptible to Hollow Heart, a condition in which a hollow depression forms in the center of the potato when moisture levels are very uneven while the potatoes are growing.

    “But diseases and pests keep evolving, so we need to keep breeding new varieties to stay ahead of them,” explained Research Geneticist Richard Novy, with the Small Grains and Potato Germplasm Research Unit in Aberdeen, Idaho.

    Every year, scientists in the ARS potato breeding program make thousands of chipping potato crosses with an eye to improving not only disease and pest resistance, but also achieving perfect potato chip color and proper sugar levels, good storage ability and a whole host of superior agronomic traits such as yield, time to harvest and tuber size.

    Novy has a very promising new chipping potato in the pipeline at Aberdeen, known right now as A13125-3C, which is showing much potential in Idaho and in the National Chip Processing Trial (NCPT). ARS participates alongside universities and industry in the NCPT, which is run through Potatoes USA, to test potatoes simultaneously at sites all over the country.

    A13125-3C won’t get a catchy variety name until after it successfully completes several years of trials and then goes through a tissue culture process to remove any viruses and bacteria to allow the production of certified seed for producers.

    “By sharing access to germplasm and testing nationally, you can more quickly identify candidates having variety potential for the chipping industry,” Novy said. “Such a program helps regional chip companies to identify promising new potato varieties for their production of chips.”

    Across the country from the Aberdeen lab, ARS Plant Research Geneticist Paul Collins in Orono, Maine, is concentrating on breeding chipping potatoes with better disease resistance for eastern potato growers. One major focus is potatoes that can better withstand Late Blight, a fungal disease that causes an annual loss of $210 million.

    “Most diseases we are working on can affect the farmer’s ability to produce a potato crop and they can have a staggering economic impact,” Collins said. “Potato Virus Y, for example, causes annual losses of $103 million in yield and tuber quality.

    While ARS scientists are breeding potatoes to fight diseases, most consumers do not have to worry about their snack being affected by any of these viruses. The chipping varieties for the snack aisle, usually Atlantic, Snowden and Lamoka, are not found in the grocery store’s produce bins.

    “Our goal is to breed potato varieties which are resistant to these diseases, and with other agronomic traits that are important to farmers while also having quality traits like color, shape and size that are important to consumers and processors,” Collins said.

    The Agricultural Research Service is the U.S. Department of Agriculture’s chief scientific in-house research agency. Daily, ARS focuses on solutions to agricultural problems affecting America. Each dollar invested in U.S. agricultural research results in $20 of economic impact.

  • An Organic Alternative to Combatting Spotted Wing Drosophila

    Scientists from the Agricultural Research Service (ARS) are working to understand how something can be equally effective as both a government-approved food additive and as a pesticide.

    Methyl benzoate is a naturally occurring compound produced by plants. The U.S. Food and Drug Administration long ago approved methyl benzoate for human use; its fruity and floral aroma makes it a staple in perfumes and cosmetics and as a food additive. Nature employs it to attract pollinators.

    While many insects find methyl benzoate appealing, Aijun Zhang, research chemist at the ARS Invasive Insect Biocontrol and Behavior Laboratory in Beltsville, MD, is investigating why some insects and non-insect pests find it revolting.

    From left, research chemist Aijun Zhang, postdoctoral Nick Larson, and intern Lauryn Brooks demonstrated research into methyl benzoate uses as a pesticide in an ARS poster day demonstration.

    Zhang’s research has focused on methyl benzoate’s utility as a pesticide for human protection and crop protection. So far, Zhang has documented that the compound will kill or repel many insects in various stages of development, including mosquitoes, bed bugs, fire ants, ticks, flies, moths, and the brown marmorated stink bug. Perhaps most important, however, is its ability to repel and kill the spotted wing drosophila fly (SWD). “SWD is the most significant invasive insect pest of soft-skinned fruit crops in the USA,” Zhang said.

    Since SWD was first detected in California a little over a decade ago, the fly has become a key pest in blueberries, blackberries, raspberries, strawberries, and cherries. These crops have a combined annual value of over $5.8 billion, and farmers lose about $718 million annually to SWD damage.

    Farmers fight SWD with synthetic insecticides, but at prices up to $1,200 per acre, that method is expensive. It is costly in other ways, too, Zhang said; the synthetic insecticide is harmful to the environment, contributes to pesticide resistance, and may be harmful to humans.

    Because methyl benzoate is an environmentally friendly, bio-based compound, Zhang thinks it has great potential to be used by people for human protection as an alternative to synthetic pesticides. It also costs much less than synthetic pesticide treatments.

    According to Zhang, methyl benzoate shares the same “chemical skeleton” as DEET, the gold standard in arthropod repellency, a detail that is leading future research efforts.

    “Understanding the structure-activity relationship will allow researchers to modify the chemical structure of the methyl benzoate molecule to develop pesticides that are more efficient at controlling arthropod pests,” he said. — By Scott Elliott, USDA-ARS Office of Communications.

  • Water & Small Fruit Scientists Named to ARS Hall of Fame

    Two scientists have earned a place in the Agricultural Research Service (ARS) Science Hall of Fame for their pioneering and impactful research in small-fruits breeding and remote sensing for improved irrigation water scheduling.

    Chad E. Finn (posthumously) and William P. Kustas will be inducted in a virtual ceremony today rather than a physical event due to ongoing COVID-19 safety precautions. ARS established the Science Hall of Fame in 1986 to honor senior agency researchers for outstanding, lifelong achievements in agricultural science and technology.

    “Our two inductees exemplify the scientific excellence that has made ARS a premier research agency and world leader in addressing important issues facing agriculture today,” said Acting ARS Administrator Simon Liu.

    A plant geneticist at the ARS Horticultural Crops Research Laboratory in Corvallis, Oregon, Finn, who died December 17, 2019, is being posthumously honored for his outstanding and sustained contributions to the advancement of small-fruits crop research. His accomplishments include the development and release or co-release of more than 57 blackberry, raspberry, blueberry and strawberry varieties, some of which have become industry standards generating more than $450 million in fruit and plant sales over the past 10 years.

    Finn’s research endeavors have led to a small-fruits germplasm program that’s considered among the world’s most diverse and extensive, spanning several genera of plants including Rubus, Fragaria, Vaccinium and Actinidia. His discoveries provide a greater understanding and characterization of wild species in these genera as well as their importance as novel sources of genetic variability and useful traits such as aphid resistance and fruit processing quality.

    Finn also led an international black raspberry research project that developed a draft black raspberry genome—the first in the genus Rubus. Similar genomic efforts are underway in other berry crops. Throughout, he was a mentor to graduate students, avid presenter and participant on numerous committees and associations.

    Kustas, a hydrologist at the ARS Hydrology and Remote Sensing Laboratory in Beltsville, Maryland, is being honored for scientific accomplishments that include using satellite data with computer models for mapping evapotranspiration (ET)—the process of plant water use through transpiration and water loss or evaporation from the soil.

    In addition to monitoring ET, plant stress and drought, other applications of the models arising from Kustas and colleagues’ pioneering research include precise targeting of irrigation water to crops, including the vineyards of E&J Gallo Winery in California’s Central Valley. There, as part of the Grape Remote-sensing Atmospheric Profile and Evapotranspiration eXperiment (GRAPEX), Kustas and collaborators from NASA, Utah State University, University of California-Davis and Gallo are helping the winery better track soil and vine moisture levels with a view to reducing irrigation water use by up to 25 percent. Potentially, this reduction could translate to significant economic savings as well as contributing to sustainable groundwater management—a benefit the GRAPEX team expects could apply to other Central Valley vineyards as well as California’s nut orchard industry, which spans 1.5 million acres. “ET Toolkits” resulting from the project are also being readied for use in other water-limited western states.

  • Plant, Insect Viruses Work Together to Spread Disease

    In what may be a first for science, researchers with the Agricultural Research Service (ARS) have found an example of plant and insect viruses working together to increase their spread.

    Molecular biologist Michelle Heck, of the ARS Emerging Pests and Pathogens Research Lab in Ithaca, NY, scouts for aphids (Photo by Jennifer Wilson, Cornell University).

    Michelle Heck, an ARS research molecular biologist, was leading research into poleroviruses, a type of plant virus spread by aphids, when she and Cornell University graduate students Jenny Wilson and Patricia Pinheiro made the surprising discovery. Heck is in ARS’s Emerging Pests and Pathogens Research Unit at the Boyce Thompson Institute, on the campus of Cornell University, in Ithaca, NY.

    “Poleroviruses produce a molecule, called P Zero (P0), which dampens the aphid’s immune system,” Heck said. “When the aphid immune’s system is turned down, it allows an aphid virus called a densovirus to infect the insect at very high levels.”

    Densoviruses have a curious effect on aphids: Aphids usually develop wings when the weather begins to cool, but densoviruses can induce the insects to sprout wings. When poleroviruses and densoviruses interact in this way, it allows them to carry the polerovirus farther and faster.

    “We think this is the result of evolution,” Heck said. “Both the plant virus and the insect virus have evolved to manipulate the aphid. Our work shows they are in cahoots to promote virus spread, though possibly at the aphid’s expense.”

    The research is vital to crop producers because aphids transmit more than 100 different viruses to peaches, tomatoes, potatoes, apples, cotton, cabbage, corn, and other plants. In particular, the potato leafroll virus can reduce the worldwide potato yield by more than 50 percent, causing the loss of 20 million tons of crop each year. There is a new and emerging polerovirus infecting cotton, cotton leafroll dwarf virus, that Heck and her team are now studying.

    “Aphids are resistant to many commonly used insecticides, so chemical treatment is not effective in killing them and blocking the spread of viruses,” Heck said. “By the time a farmer notices aphids in the field, it is too late to block the spread of these viruses by aphids.”

    Follow-on research includes a quest to understand how the polerovirus protein, P0, suppresses the aphid’s immune system at the molecular level. Heck is also looking at exactly how the densovirus triggers the aphid to grow wings.

    “We now know that poleroviruses can interfere with the aphid’s immune response to densoviruses,” she said. The question Heck hopes to answer is, can the densovirus infection be made so severe that it kills the aphids, and if so, could it be used as a biological control tool? – By Scott Elliott, ARS Office of Communications

  • Plant, Insect Viruses Work Together to Spread Disease

    In what may be a first for science, researchers with the Agricultural Research Service (ARS) have found an example of plant and insect viruses working together to increase their spread.

    Molecular biologist Michelle Heck, of the ARS Emerging Pests and Pathogens Research Lab in Ithaca, NY, scouts for aphids (Photo by Jennifer Wilson, Cornell University).

    Michelle Heck, an ARS research molecular biologist, was leading research into poleroviruses, a type of plant virus spread by aphids, when she and Cornell University graduate students Jenny Wilson and Patricia Pinheiro made the surprising discovery. Heck is in ARS’s Emerging Pests and Pathogens Research Unit at the Boyce Thompson Institute, on the campus of Cornell University, in Ithaca, NY.

    “Poleroviruses produce a molecule, called P Zero (P0), which dampens the aphid’s immune system,” Heck said. “When the aphid immune’s system is turned down, it allows an aphid virus called a densovirus to infect the insect at very high levels.”

    Densoviruses have a curious effect on aphids: Aphids usually develop wings when the weather begins to cool, but densoviruses can induce the insects to sprout wings. When poleroviruses and densoviruses interact in this way, it allows them to carry the polerovirus farther and faster.

    “We think this is the result of evolution,” Heck said. “Both the plant virus and the insect virus have evolved to manipulate the aphid. Our work shows they are in cahoots to promote virus spread, though possibly at the aphid’s expense.”

    The research is vital to crop producers because aphids transmit more than 100 different viruses to peaches, tomatoes, potatoes, apples, cotton, cabbage, corn, and other plants. In particular, the potato leafroll virus can reduce the worldwide potato yield by more than 50 percent, causing the loss of 20 million tons of crop each year. There is a new and emerging polerovirus infecting cotton, cotton leafroll dwarf virus, that Heck and her team are now studying.

    “Aphids are resistant to many commonly used insecticides, so chemical treatment is not effective in killing them and blocking the spread of viruses,” Heck said. “By the time a farmer notices aphids in the field, it is too late to block the spread of these viruses by aphids.”

    Follow-on research includes a quest to understand how the polerovirus protein, P0, suppresses the aphid’s immune system at the molecular level. Heck is also looking at exactly how the densovirus triggers the aphid to grow wings.

    “We now know that poleroviruses can interfere with the aphid’s immune response to densoviruses,” she said. The question Heck hopes to answer is, can the densovirus infection be made so severe that it kills the aphids, and if so, could it be used as a biological control tool? – By Scott Elliott, ARS Office of Communications

  • First Genome of Spotted Lanternfly Built from a Single Insect

    Agricultural Research Service (ARS) scientists, in cooperation with Pacific Biosciences and Penn State University, have published the first genome of the invasive Spotted Lanternfly (SLF) in the journal Gigascience and they did it from a single caught-in-the-wild specimen.

    Not only is it the first published genome for this pest, but no closely related species has had its genome sequenced, making the data even more important, according to entomologist Scott M. Geib with the ARS Daniel K Inouye U.S. Pacific Basin Agricultural Research Center.

    SLF, a native of China, Bangladesh and Vietnam, was first found in Pennsylvania in 2014 and has now spread to Virginia, Maryland and New York. This invasive pest has a taste for almonds, apples, apricots, grapes, peaches, blueberries and hops as well as hardwoods such as oak, walnut, and poplar. Various estimates put the potential economic damage in the billions of dollars, if the SLF becomes widely established in the United States.

    “Having the genome for this pest opens the door to a better understanding of its biology and behavior, and makes coming up with potential control methods much more likely to happen, such as developing a lure for a trap through understanding the insect’s olfactory genes, or exploring avenues such as gene editing or RNAi,” said Geib.

    While having the SLF genome is critical for the management and control of this invasive pest, the approach taken to obtain the genetic data is an achievement of remarkable note as well. For the first time, all of the DNA required to generate a whole genome sequence was taken from a single insect picked from a tree in the wild in Reading, Pennsylvania, across the street from the Reading Pagoda on Mt. Penn.

    One hurdle for deciphering this species’ genome is its relatively large genome size, at about 2.2 billion base pairs. Typically, with previous sequencing systems, many sequencing runs would have been needed to do the complete job, with each run using up the available DNA for the organism being sequenced.

    So often to have sufficient DNA for a complete genome sequence, many organisms would need to be pooled, introducing more opportunities for errors to be generated. To avoid such potential for errors, the subjects—especially insects—often have to be raised in colonies and inbred.

    “In cooperation with Pacific Biosciences and using their new sequencing platform—the PacBio Sequel II—that produces 10 times the data from a single sequencing run, we were able to generate sufficient coverage from just a single specimen. This allows for a very fast turn-around of data and assemblies as well as lowers cost, in this case under $2,000 in consumable supplies, not including the purchase price of the sequencing instrument of course,” explained Geib.

    For genome completeness, and since there aren’t many related genomes to compare that of the SLF to, the team checked a set of “core genes” that should be present exactly one time in all insects and verified how many of these were found in this genome project. In this case, they found about 97 percent of these single copy core genes, with a very low rate of duplication.

    “Sequencing such a large insect genome quickly and showing there is no need to pull the insect into a colony raises the feasibility that we can complete the Ag100Pest Project,” Geib said. The ARS Ag100Pest initiative is focused on deciphering the genomes of 100 insect species that are most destructive to crops and livestock and that are projected to have profound bioeconomic impacts to agriculture and the environment. “Now, with this system, doing 100 or even 1,000 genomes is not unrealistic,” he added.

    The ability to get a complete genome from a small amount of DNA also makes it practical to consider sequencing the genomes of physically tiny insects without having to catch or raise a large number of any one species. That expands the list of insects that may be genetically sequenced.

    By Kim Kaplan, USDA-ARS

    The Agricultural Research Service is the U.S. Department of Agriculture’s chief scientific in-house research agency. Daily, ARS focuses on solutions to agricultural problems affecting America. Each dollar invested in agricultural research results in $20 of economic impact.