Genome Sequence Of Fungus Reveals Unsuspected Ability To Use Complex Carbon Sources
ScienceDaily (May 6, 2008) — The model fungus Podospora anserina (P. anserina) has undergone substantial evolution since its separation from Neurospora crassa, as revealed from the Podospora draft genome sequence published in Genome Biology. The study also shows that the Podospora genome contains a large, highly specialised set of genes potentially involved in the breakdown of complex carbon sources, which may have potential use in biotechnology applications.
P. anserina is a dung-inhabiting, saprophytic fungus used to study areas of eukaryotic and fungal biology, including ageing and sexual development. Eric Espagne, Olivier Lespinet and Fabienne Malagnac from the Institute of Genetics and Microbiology in Paris and a team of researchers from France and The Netherlands used a whole genome shotgun and assembly approach to produce a 10X draft sequence of the fungus.
The researchers found evidence that P. anserina has undergone dynamic evolution since it diverged from its close relative N. crassa. They found evidence of extensive gene loss and gene shuffling, as well as substantial gene duplication. In addition, the transcription machinery of P. anserina produced a large number of RNAs that could potentially have regulatory roles. Further investigation of these non-conventional transcripts is required and could lead to the discovery of novel regulatory mechanisms, specifically during mycelium growth or accompanying the differentiation of the multicellular fructification produced during sexual reproduction.
The research team also discovered that P. anserina contains a large array of genes that may allow the fungus to use the natural carbon sources found wherever it grows. For example, the fungus carries genes potentially involved in the breakdown of the plant polymers cellulose and lignin, which may have future applications in biotechnology.
Espagne concludes: "As for other saprophytic fungi, the P. anserina genome sequence has opened new avenues in the comprehensive study of a variety of biological processes ... It also demonstrates how P. anserina is well adapted at the genome level to its natural environment, which was confirmed by the analysis of growth profiles. This result emphasizes the necessity to study several less well-tracked organisms in addition to those well known in the scientific community, as these may yield unexpected new insights into biological phenomena of general interest."
Journal reference: The genome sequence of the model ascomycete fungus Podospora anserina
Eric Espagne, Olivier Lespinet, Fabienne Malagnac, Corinne Da Silva, Olivier Jaillon, Betina M Porcel, Arnaud Couloux, Jean-Marc Aury, Béatrice Segurens, Julie Poulain, Véronique Anthouard, Sandrine Grossetete, Hamid Khalili, Evelyne Coppin, Michelle Déquart-Chablat, Marguerite Picard, Véronique Contamine, Sylvie Arnaise, Anne Bourdais, Véronique Berteaux-Lecellier, Daniel Gautheret, Ronald P de Vries, Evy Battaglia, Pedro M Coutinho, Etienne GJ Danchin, Bernard Henrissat, Ryiad El Khoury, Annie Sainsard-Chanet, Antoine Boivin, Bérangère Pinan-Lucarré, Carole H Sellem, Robert Debuchy, Patrick Wincker, Jean Weissenbach and Philippe Silar
Genome Biology (in press)
--------------------------------------------------------------------------------
Adapted from materials provided by Genome Biology, via EurekAlert!, a service of AAAS.
Sunday, June 29, 2008
Mushrooms As Good An Antioxidant Source As More Colorful Veggies
Mushrooms As Good An Antioxidant Source As More Colorful Veggies
ScienceDaily (June 27, 2006) — Portabella and crimini mushrooms rank with carrots, green beans, red peppers and broccoli as good sources of dietary antioxidants, Penn State researchers say.
N. Joy Dubost, who recently earned her doctorate in food science at Penn State, measured the activity of two antioxidants, polyphenols and ergothioneine, present in mushrooms, using the ORAC assay and HPLC instrumentation, as part of her dissertation research. She found that portabella mushrooms had an ORAC value of 9.7 micromoles of trolox equivalents per gram and criminis had an ORAC value of 9.5. Data available from other researchers shows carrots and green beans have an ORAC value of 5; red pepper 10; and broccoli 12.
The ORAC assay, the most well known test of antioxidant capacity, focuses on the peroxyl radical, the most predominate in the human body. Free radicals, such as the peroxyl radical, are thought to play a role in the aging process and in many diseases, including cancer, Alzheimer's and atherosclerosis. Epidemiological studies have shown that those who eat the most fruits and vegetables rich in antioxidants have lower incidence of these diseases.
Dubost detailed her results in a paper, Quantification of Polyphenols and Ergothioneine in Cultivated Mushrooms and Correlation to Total Antioxidant Capacity Using the ORAC and HORAC Assays, presented Monday, June 26, at the Institute of Food Technologists meeting in Orlando, Fl. Her co-author is her dissertation adviser, Dr. Robert Beelman, professor of food science.
Dubost explains that assays are a first step toward determining how effective a food is in providing protection against oxidative damage. Anti-oxidants inhibit increased rates of oxidation, which can damage proteins, lipids carbohydrates and DNA.
She adds, "The ORAC assay does not tell what happens in the human body but this assay is currently under investigation as to how it can predict physiological activity."
The Penn State study showed that the anti-oxidant effect of mushrooms is due primarily to the presence of polyphenols. Dubost and Beelman had earlier identified mushrooms as an abundant source of the anti-oxidant, ergothionene.
Dubost notes, "Evidence suggests that erogothioneine is biologically very important and, even though the assay used does not show it contributes to total antioxidant activity in the mushrooms, it may significantly contribute antioxidant activity in the body."
The ORAC values found in the latest study indicate that mushrooms are potent anti-oxidant sources. The research revealed that, of the mushrooms tested, portabella mushrooms and crimini mushrooms have the highest ORAC values. Criminis, which are brown, are otherwise similar to the popular white button mushroom, the one mostly commonly consumed in the U.S. The white button mushroom has an ORAC value of 6.9, above tomato, green pepper, pumpkin, zucchini, carrot, and green beans.
Dubost says, "You don't have to eat only the vegetables with the highest anti-oxidant capacity to benefit. If you eat a variety of mushrooms along with a variety of other vegetables, you'll be getting a variety of antioxidants."
The study was supported by The Mushroom Council, NutriCore Northeast and the Pennsylvania Agricultural Experiment Station.
--------------------------------------------------------------------------------
Adapted from materials provided by Penn State.
ScienceDaily (June 27, 2006) — Portabella and crimini mushrooms rank with carrots, green beans, red peppers and broccoli as good sources of dietary antioxidants, Penn State researchers say.
N. Joy Dubost, who recently earned her doctorate in food science at Penn State, measured the activity of two antioxidants, polyphenols and ergothioneine, present in mushrooms, using the ORAC assay and HPLC instrumentation, as part of her dissertation research. She found that portabella mushrooms had an ORAC value of 9.7 micromoles of trolox equivalents per gram and criminis had an ORAC value of 9.5. Data available from other researchers shows carrots and green beans have an ORAC value of 5; red pepper 10; and broccoli 12.
The ORAC assay, the most well known test of antioxidant capacity, focuses on the peroxyl radical, the most predominate in the human body. Free radicals, such as the peroxyl radical, are thought to play a role in the aging process and in many diseases, including cancer, Alzheimer's and atherosclerosis. Epidemiological studies have shown that those who eat the most fruits and vegetables rich in antioxidants have lower incidence of these diseases.
Dubost detailed her results in a paper, Quantification of Polyphenols and Ergothioneine in Cultivated Mushrooms and Correlation to Total Antioxidant Capacity Using the ORAC and HORAC Assays, presented Monday, June 26, at the Institute of Food Technologists meeting in Orlando, Fl. Her co-author is her dissertation adviser, Dr. Robert Beelman, professor of food science.
Dubost explains that assays are a first step toward determining how effective a food is in providing protection against oxidative damage. Anti-oxidants inhibit increased rates of oxidation, which can damage proteins, lipids carbohydrates and DNA.
She adds, "The ORAC assay does not tell what happens in the human body but this assay is currently under investigation as to how it can predict physiological activity."
The Penn State study showed that the anti-oxidant effect of mushrooms is due primarily to the presence of polyphenols. Dubost and Beelman had earlier identified mushrooms as an abundant source of the anti-oxidant, ergothionene.
Dubost notes, "Evidence suggests that erogothioneine is biologically very important and, even though the assay used does not show it contributes to total antioxidant activity in the mushrooms, it may significantly contribute antioxidant activity in the body."
The ORAC values found in the latest study indicate that mushrooms are potent anti-oxidant sources. The research revealed that, of the mushrooms tested, portabella mushrooms and crimini mushrooms have the highest ORAC values. Criminis, which are brown, are otherwise similar to the popular white button mushroom, the one mostly commonly consumed in the U.S. The white button mushroom has an ORAC value of 6.9, above tomato, green pepper, pumpkin, zucchini, carrot, and green beans.
Dubost says, "You don't have to eat only the vegetables with the highest anti-oxidant capacity to benefit. If you eat a variety of mushrooms along with a variety of other vegetables, you'll be getting a variety of antioxidants."
The study was supported by The Mushroom Council, NutriCore Northeast and the Pennsylvania Agricultural Experiment Station.
--------------------------------------------------------------------------------
Adapted from materials provided by Penn State.
Button Mushrooms Contain As Much Anti-oxidants As Expensive Ones
Button Mushrooms Contain As Much Anti-oxidants As Expensive Ones
ScienceDaily (Feb. 12, 2008) — The humble white button mushroom (Agaricus bisporus) has as much, and in some cases, more anti-oxidant properties than more expensive varieties.
Although the button mushroom is the foremost cultivated edible mushroom in the world with thousands of tonnes being eaten every year, it is often thought of as a poor relation to its more exotic and expensive cousins and to have lesser value nutritionally.
But according to new research in SCI's Journal of the Science of Food and Agriculture, the white button mushroom has as much anti-oxidant properties as its more expensive rivals, the maitake and the matsutake mushrooms - both of which are highly prized in Japanese cuisine for their reputed health properties including lowering blood pressure and their alleged ability to fight cancer.
Anti-oxidants are believed to help ward off illness and boost the body's immune system by acting as free radical scavengers, helping to mop up cell damage caused by free radicals.
Dr Jean-Michel Savoie and his team from the Institut National de la Recherche Agrinomique, a Governmental research institute in France, found that anti-radical activity was equivalent to, if not more, than the better known mushrooms when they measured the respective mushrooms' free radical scavenging ability.
The French team also found that the body of the mushroom had a higher concentration of anti-oxidants than the stalk.
Dr Jean-Michel said: "It can be reasonably assumed that white button mushrooms have as much, if not more, radical scavenging power as mushrooms currently touted for their health benefit. The good thing is button mushrooms are available all year round, are cheap and may be an excellent source of nutrition as part of a healthy diet."
--------------------------------------------------------------------------------
Adapted from materials provided by Society of Chemical Industry, via EurekAlert!, a service of AAAS.
ScienceDaily (Feb. 12, 2008) — The humble white button mushroom (Agaricus bisporus) has as much, and in some cases, more anti-oxidant properties than more expensive varieties.
Although the button mushroom is the foremost cultivated edible mushroom in the world with thousands of tonnes being eaten every year, it is often thought of as a poor relation to its more exotic and expensive cousins and to have lesser value nutritionally.
But according to new research in SCI's Journal of the Science of Food and Agriculture, the white button mushroom has as much anti-oxidant properties as its more expensive rivals, the maitake and the matsutake mushrooms - both of which are highly prized in Japanese cuisine for their reputed health properties including lowering blood pressure and their alleged ability to fight cancer.
Anti-oxidants are believed to help ward off illness and boost the body's immune system by acting as free radical scavengers, helping to mop up cell damage caused by free radicals.
Dr Jean-Michel Savoie and his team from the Institut National de la Recherche Agrinomique, a Governmental research institute in France, found that anti-radical activity was equivalent to, if not more, than the better known mushrooms when they measured the respective mushrooms' free radical scavenging ability.
The French team also found that the body of the mushroom had a higher concentration of anti-oxidants than the stalk.
Dr Jean-Michel said: "It can be reasonably assumed that white button mushrooms have as much, if not more, radical scavenging power as mushrooms currently touted for their health benefit. The good thing is button mushrooms are available all year round, are cheap and may be an excellent source of nutrition as part of a healthy diet."
--------------------------------------------------------------------------------
Adapted from materials provided by Society of Chemical Industry, via EurekAlert!, a service of AAAS.
Shiitake Mushrooms May Improve Human Immune Function, Especially If Grown On Old Oak Logs
Shiitake Mushrooms May Improve Human Immune Function, Especially If Grown On Old Oak Logs
ScienceDaily (June 29, 2008) — Shiitake (Lentinula edodes) mushrooms are good for you--and shiitake byproducts can be good for other crops.
These mushrooms contain high-molecular-weight polysaccharides (HMWP), which some studies suggest may improve human immune function. Other research indicates that the shiitake compound eritadenine may help lower cholesterol levels.
Agricultural Research Service (ARS) agronomist David Brauer has been studying shiitake production at the agency's Dale Bumpers Small Farm Research Center, Booneville, Ark. Working in collaboration with producers at the Shiitake Mushroom Center in Shirley, Ark., Brauer evaluated whether shiitakes grown on logs have higher levels of HMWP than shiitakes grown on commercial substrates.
The group inoculated logs with spores from three different shiitake varieties and compared the yield with shiitake yields grown on commercial substrates. They found that the log-grown shiitakes had HMWP levels as much as 70 percent higher than the substrate-grown shiitakes. The team also observed that shiitakes grown on red and white oak logs had higher levels of HMWP than shiitakes grown on sweet gum logs.
Logs used in shiitake production generally provide good yields for around two to three years. Larger shiitake farms may have 3,000 or more logs on the premises, and retire around 1,000 of them every year.
Not to let those used logs go to waste, Brauer’s team chipped a selection of spent logs, added urea and green grass cuttings to the chips and then composted the mixture. They found that the nitrogen levels in the resulting compost were comparable to nitrogen levels in other purchased soil amendment materials.
The researchers used the log compost to amend soil in a greenhouse spinach production system and found that the seedlings exhibited greater growth rates than seedlings cultivated in soil that had not been amended. Using recycled log compost provides another way for shiitake mushroom growers to increase their profits.
In 2004-2005, producers harvested approximately 9 million pounds of shiitake mushrooms, which sold for an average price of $3.21 per pound. Brauer’s findings lend a range of support to farmers interested in starting--or boosting profits from--log-grown shiitake production.
--------------------------------------------------------------------------------
Adapted from materials provided by USDA/ Agricultural Research Service.
ScienceDaily (June 29, 2008) — Shiitake (Lentinula edodes) mushrooms are good for you--and shiitake byproducts can be good for other crops.
These mushrooms contain high-molecular-weight polysaccharides (HMWP), which some studies suggest may improve human immune function. Other research indicates that the shiitake compound eritadenine may help lower cholesterol levels.
Agricultural Research Service (ARS) agronomist David Brauer has been studying shiitake production at the agency's Dale Bumpers Small Farm Research Center, Booneville, Ark. Working in collaboration with producers at the Shiitake Mushroom Center in Shirley, Ark., Brauer evaluated whether shiitakes grown on logs have higher levels of HMWP than shiitakes grown on commercial substrates.
The group inoculated logs with spores from three different shiitake varieties and compared the yield with shiitake yields grown on commercial substrates. They found that the log-grown shiitakes had HMWP levels as much as 70 percent higher than the substrate-grown shiitakes. The team also observed that shiitakes grown on red and white oak logs had higher levels of HMWP than shiitakes grown on sweet gum logs.
Logs used in shiitake production generally provide good yields for around two to three years. Larger shiitake farms may have 3,000 or more logs on the premises, and retire around 1,000 of them every year.
Not to let those used logs go to waste, Brauer’s team chipped a selection of spent logs, added urea and green grass cuttings to the chips and then composted the mixture. They found that the nitrogen levels in the resulting compost were comparable to nitrogen levels in other purchased soil amendment materials.
The researchers used the log compost to amend soil in a greenhouse spinach production system and found that the seedlings exhibited greater growth rates than seedlings cultivated in soil that had not been amended. Using recycled log compost provides another way for shiitake mushroom growers to increase their profits.
In 2004-2005, producers harvested approximately 9 million pounds of shiitake mushrooms, which sold for an average price of $3.21 per pound. Brauer’s findings lend a range of support to farmers interested in starting--or boosting profits from--log-grown shiitake production.
--------------------------------------------------------------------------------
Adapted from materials provided by USDA/ Agricultural Research Service.
Biofuels: Fungus Use Improves Corn-to-ethanol Process
Biofuels: Fungus Use Improves Corn-to-ethanol Process
ScienceDaily (May 30, 2008) — Growing a fungus in some of the leftovers from ethanol production can save energy, recycle more water and improve the livestock feed that's a co-product of fuel production, according to a team of researchers from Iowa State University and the University of Hawai'i.
"The process could change ethanol production in dry-grind plants so much that energy costs can be reduced by as much as one-third," said Hans van Leeuwen, an Iowa State professor of civil, construction and environmental engineering and the leader of the research project.
Van Leeuwen and the other researchers developing the technology -- Anthony L. Pometto III, a professor of food science and human nutrition; Mary Rasmussen, a graduate student in environmental engineering and biorenewable resources and technology; and Samir Khanal, a former Iowa State research assistant professor who's now an assistant professor of molecular biosciences and bioengineering at the University of Hawai'i at Manoa -- recently won the 2008 Grand Prize for University Research from the American Academy of Environmental Engineers for the project.
"Those chosen for prizes by an independent panel of distinguished experts address the broad range of modern challenges inherent in providing life-nurturing services for humans and protection of the environment," according to a statement from the academy. "... Their innovations and performance illustrate the essential role of environmental engineers in providing a healthy planet."
The Iowa State project is focused on using fungi to clean up and improve the dry-grind ethanol production process. That process grinds corn kernels and adds water and enzymes. The enzymes break the starches into sugars. The sugars are fermented with yeasts to produce ethanol.
The fuel is recovered by distillation, but there are about six gallons of leftovers for every gallon of fuel that's produced. Those leftovers, known as stillage, contain solids and other organic material. Most of the solids are removed by centrifugation and dried into distillers dried grains that are sold as livestock feed, primarily for cattle.
The remaining liquid, known as thin stillage, still contains some solids, a variety of organic compounds from corn and fermentation as well as enzymes. Because the compounds and solids can interfere with ethanol production, only about 50 percent of thin stillage can be recycled back into ethanol production. The rest is evaporated and blended with distillers dried grains to produce distillers dried grains with solubles.
The researchers added a fungus, Rhizopus microsporus, to the thin stillage and found it would feed and grow. The fungus removes about 80 percent of the organic material and all of the solids in the thin stillage, allowing the water and enzymes in the thin stillage to be recycled back into production.
The fungus can also be harvested. It's a food-grade organism that's rich in protein, certain essential amino acids and other nutrients. It can be dried and sold as a livestock feed supplement. Or it can be blended with distillers dried grains to boost its value as a livestock feed and make it more suitable for feeding hogs and chickens.
Van Leeuwen said all of that can save United States ethanol producers a lot of energy and money at current production levels:
Eliminating the need to evaporate thin stillage would save ethanol plants up to $800 million a year in energy costs.
Allowing more water recycling would reduce the industry's water consumption by as much as 10 billion gallons per year. And it allows producers to recycle enzymes in the thin stillage, saving about $60 million per year.
Adding value and nutrients to the livestock feed produced by ethanol plants would grow the market for that feed by about $400 million per year.
And the researchers' fungal process would improve the energy balance of ethanol production by reducing energy inputs so there is more of an energy gain.
Van Leeuwen estimated it would cost $11 million to start using the process in an ethanol plant that produces 100 million gallons of fuel per year. But, he said the cost savings at such a plant could pay off that investment in about six months.
The Iowa State research project is supported by grants of $78,806 from the Grow Iowa Values Fund, a state economic development program, and $80,000 from the U.S. Department of Agriculture through the Iowa Biotechnology Byproducts Consortium.
The researchers have filed for a patent on the technology and are looking for investors to commercialize the invention. And while the process needs to be proven at larger scales, there are high hopes it can do a lot to improve the efficiency of ethanol production.
"We will be saving ethanol producers money and energy," Pometto said. "That's the bottom line."
--------------------------------------------------------------------------------
Adapted from materials provided by Iowa State University.
ScienceDaily (May 30, 2008) — Growing a fungus in some of the leftovers from ethanol production can save energy, recycle more water and improve the livestock feed that's a co-product of fuel production, according to a team of researchers from Iowa State University and the University of Hawai'i.
"The process could change ethanol production in dry-grind plants so much that energy costs can be reduced by as much as one-third," said Hans van Leeuwen, an Iowa State professor of civil, construction and environmental engineering and the leader of the research project.
Van Leeuwen and the other researchers developing the technology -- Anthony L. Pometto III, a professor of food science and human nutrition; Mary Rasmussen, a graduate student in environmental engineering and biorenewable resources and technology; and Samir Khanal, a former Iowa State research assistant professor who's now an assistant professor of molecular biosciences and bioengineering at the University of Hawai'i at Manoa -- recently won the 2008 Grand Prize for University Research from the American Academy of Environmental Engineers for the project.
"Those chosen for prizes by an independent panel of distinguished experts address the broad range of modern challenges inherent in providing life-nurturing services for humans and protection of the environment," according to a statement from the academy. "... Their innovations and performance illustrate the essential role of environmental engineers in providing a healthy planet."
The Iowa State project is focused on using fungi to clean up and improve the dry-grind ethanol production process. That process grinds corn kernels and adds water and enzymes. The enzymes break the starches into sugars. The sugars are fermented with yeasts to produce ethanol.
The fuel is recovered by distillation, but there are about six gallons of leftovers for every gallon of fuel that's produced. Those leftovers, known as stillage, contain solids and other organic material. Most of the solids are removed by centrifugation and dried into distillers dried grains that are sold as livestock feed, primarily for cattle.
The remaining liquid, known as thin stillage, still contains some solids, a variety of organic compounds from corn and fermentation as well as enzymes. Because the compounds and solids can interfere with ethanol production, only about 50 percent of thin stillage can be recycled back into ethanol production. The rest is evaporated and blended with distillers dried grains to produce distillers dried grains with solubles.
The researchers added a fungus, Rhizopus microsporus, to the thin stillage and found it would feed and grow. The fungus removes about 80 percent of the organic material and all of the solids in the thin stillage, allowing the water and enzymes in the thin stillage to be recycled back into production.
The fungus can also be harvested. It's a food-grade organism that's rich in protein, certain essential amino acids and other nutrients. It can be dried and sold as a livestock feed supplement. Or it can be blended with distillers dried grains to boost its value as a livestock feed and make it more suitable for feeding hogs and chickens.
Van Leeuwen said all of that can save United States ethanol producers a lot of energy and money at current production levels:
Eliminating the need to evaporate thin stillage would save ethanol plants up to $800 million a year in energy costs.
Allowing more water recycling would reduce the industry's water consumption by as much as 10 billion gallons per year. And it allows producers to recycle enzymes in the thin stillage, saving about $60 million per year.
Adding value and nutrients to the livestock feed produced by ethanol plants would grow the market for that feed by about $400 million per year.
And the researchers' fungal process would improve the energy balance of ethanol production by reducing energy inputs so there is more of an energy gain.
Van Leeuwen estimated it would cost $11 million to start using the process in an ethanol plant that produces 100 million gallons of fuel per year. But, he said the cost savings at such a plant could pay off that investment in about six months.
The Iowa State research project is supported by grants of $78,806 from the Grow Iowa Values Fund, a state economic development program, and $80,000 from the U.S. Department of Agriculture through the Iowa Biotechnology Byproducts Consortium.
The researchers have filed for a patent on the technology and are looking for investors to commercialize the invention. And while the process needs to be proven at larger scales, there are high hopes it can do a lot to improve the efficiency of ethanol production.
"We will be saving ethanol producers money and energy," Pometto said. "That's the bottom line."
--------------------------------------------------------------------------------
Adapted from materials provided by Iowa State University.
Knowledge Of Nitrogen Transfer Between Plants And Beneficial Fungi Expands
Knowledge Of Nitrogen Transfer Between Plants And Beneficial Fungi Expands
ScienceDaily (June 23, 2005) — New findings show that a beneficial soil fungus plays a large role in nitrogen uptake and utilization in most plants.
In a recent issue of the journal Nature, Agricultural Research Service (ARS) chemist Philip E. Pfeffer and cooperators report that beneficial arbuscular mycorrhizal (AM) fungi transfer substantial amounts of nitrogen to their plant hosts. A lack of soil nitrogen often limits plant growth.
The studies were conducted by Pfeffer and David Douds at the ARS Eastern Regional Research Center, Wyndmoor, Pa.; Michigan State University scientists headed by Yair Shachar-Hill; and New Mexico State University scientists headed by Peter J. Lammers and including graduate student Manjula Govindarajulu.
AM is the most common type of symbiotic fungus that colonizes the roots of most crop plants. The fungi receive glucose and possibly other organic materials from the plant, while enhancing the plant's ability to take up mineral nutrients, primarily phosphorus.
The scientists previously identified enzymes and genes involved in nitrogen absorption and breakdown in AM fungi, but very little was known about how nitrogen is moved from fungus to plant or in which form nitrogen moves within the fungus.
The researchers discovered a novel metabolic pathway in which inorganic nitrogen is taken up by the fungi and incorporated into an amino acid called arginine. This amino acid remains in the fungus until it is broken down and transferred to the plant.
The results show that the symbiotic relationship between mycorrhizal fungi and plants may have a much more significant role in the worldwide nitrogen cycle than previously believed. With this in mind, farmers may benefit from promoting the proliferation of mycorrhizal fungi through diminished fertilizer input, thereby making more efficient use of the nitrogen stores in agricultural soils.
ARS is the U.S. Department of Agriculture's chief scientific research agency.
--------------------------------------------------------------------------------
Adapted from materials provided by USDA / Agricultural Research Service.
ScienceDaily (June 23, 2005) — New findings show that a beneficial soil fungus plays a large role in nitrogen uptake and utilization in most plants.
In a recent issue of the journal Nature, Agricultural Research Service (ARS) chemist Philip E. Pfeffer and cooperators report that beneficial arbuscular mycorrhizal (AM) fungi transfer substantial amounts of nitrogen to their plant hosts. A lack of soil nitrogen often limits plant growth.
The studies were conducted by Pfeffer and David Douds at the ARS Eastern Regional Research Center, Wyndmoor, Pa.; Michigan State University scientists headed by Yair Shachar-Hill; and New Mexico State University scientists headed by Peter J. Lammers and including graduate student Manjula Govindarajulu.
AM is the most common type of symbiotic fungus that colonizes the roots of most crop plants. The fungi receive glucose and possibly other organic materials from the plant, while enhancing the plant's ability to take up mineral nutrients, primarily phosphorus.
The scientists previously identified enzymes and genes involved in nitrogen absorption and breakdown in AM fungi, but very little was known about how nitrogen is moved from fungus to plant or in which form nitrogen moves within the fungus.
The researchers discovered a novel metabolic pathway in which inorganic nitrogen is taken up by the fungi and incorporated into an amino acid called arginine. This amino acid remains in the fungus until it is broken down and transferred to the plant.
The results show that the symbiotic relationship between mycorrhizal fungi and plants may have a much more significant role in the worldwide nitrogen cycle than previously believed. With this in mind, farmers may benefit from promoting the proliferation of mycorrhizal fungi through diminished fertilizer input, thereby making more efficient use of the nitrogen stores in agricultural soils.
ARS is the U.S. Department of Agriculture's chief scientific research agency.
--------------------------------------------------------------------------------
Adapted from materials provided by USDA / Agricultural Research Service.
Learning More About Beneficial Soil Fungi
Learning More About Beneficial Soil Fungi
ScienceDaily (Feb. 2, 2006) — Beneficial soil fungi that help plants grow could become easier for farmers to use, based on research by Agricultural Research Service (ARS) scientists who are studying these valuable organisms.
The fungi, called mycorrhizal fungi, live inside and outside root cells and help them reach for nutrients by extending long threads called hyphae into the soil. The plant, in exchange, provides the fungi glucose and possibly other organic materials that they need to survive. Unfortunately, modern agricultural practices have reduced populations of arbuscular mycorrhizal (AM) fungi, the most common type.
By learning more about AM fungi physiology and finding ways to grow colonies without host plants, ARS scientists at the Eastern Regional Research Center in Wyndmoor, Pa., hope to make the fungi a practical option for producers.
Currently, researchers cannot cultivate an AM fungus without a host because the fungus can't complete its life cycle without the organic nutrients or other stimuli it receives from roots. Gerald Nagahashi, a chemist/cell biologist at ERRC, has been focusing on the events that must occur before the fungus can colonize a host plant.
He developed a bioassay showing that host root components--including chemical compounds exuding from the roots, root caps and root border cells--induce fungal hyphal branching. The increase in branching creates a greater potential for the fungus to find and attach to the host root surface.
Nagahashi and David D. Douds, an ERRC microbiologist, investigated how environmental factors, such as chemical compounds from host roots, blue light from the sun�s spectrum, and carbon dioxide, affect AM fungal growth, either individually or together.
Their techniques involved growing host roots in sterile culture and using sterile fungal spores to study various environmental factors individually or in combination. They found that these three factors--root chemicals, blue light and carbon dioxide--can all work independently to promote growth in AM fungi but are even more effective when applied together.
###
ARS is the U.S. Department of Agriculture's chief scientific research agency.
--------------------------------------------------------------------------------
Adapted from materials provided by USDA/Agricultural Research Service.
ScienceDaily (Feb. 2, 2006) — Beneficial soil fungi that help plants grow could become easier for farmers to use, based on research by Agricultural Research Service (ARS) scientists who are studying these valuable organisms.
The fungi, called mycorrhizal fungi, live inside and outside root cells and help them reach for nutrients by extending long threads called hyphae into the soil. The plant, in exchange, provides the fungi glucose and possibly other organic materials that they need to survive. Unfortunately, modern agricultural practices have reduced populations of arbuscular mycorrhizal (AM) fungi, the most common type.
By learning more about AM fungi physiology and finding ways to grow colonies without host plants, ARS scientists at the Eastern Regional Research Center in Wyndmoor, Pa., hope to make the fungi a practical option for producers.
Currently, researchers cannot cultivate an AM fungus without a host because the fungus can't complete its life cycle without the organic nutrients or other stimuli it receives from roots. Gerald Nagahashi, a chemist/cell biologist at ERRC, has been focusing on the events that must occur before the fungus can colonize a host plant.
He developed a bioassay showing that host root components--including chemical compounds exuding from the roots, root caps and root border cells--induce fungal hyphal branching. The increase in branching creates a greater potential for the fungus to find and attach to the host root surface.
Nagahashi and David D. Douds, an ERRC microbiologist, investigated how environmental factors, such as chemical compounds from host roots, blue light from the sun�s spectrum, and carbon dioxide, affect AM fungal growth, either individually or together.
Their techniques involved growing host roots in sterile culture and using sterile fungal spores to study various environmental factors individually or in combination. They found that these three factors--root chemicals, blue light and carbon dioxide--can all work independently to promote growth in AM fungi but are even more effective when applied together.
###
ARS is the U.S. Department of Agriculture's chief scientific research agency.
--------------------------------------------------------------------------------
Adapted from materials provided by USDA/Agricultural Research Service.
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