Its aroma is likened to that of decaying flesh or rotting meat. All who have gotten a whiff firsthand agree it’s a scent you won’t soon forget. [Read more…]
As winter turns to spring, syrup producers turn their eye to the weather forecast. They are in search of the perfect conditions to begin tapping sugar maple trees for sap. Have you ever wondered how sap from a maple tree is turned into a delicious topping for pancakes and waffles? [Read more…]
Whether sliced into a bowl of cereal, split in two and served with ice cream, or peeled and eaten, the banana is a common part of the American diet. Americans eat more bananas annually than oranges and apples combined. Bananas are an excellent source of vitamins, including B6 and C, magnesium, potassium, and fiber. While Americans typically view bananas as a snack food, in other parts of the world, they hold a much more important nutritional role. In some areas of Africa, where more than 200 species of the fruit are grown, bananas account for 80% of consumed calories. However, the banana that you know and love a variety called the Cavendish is in danger of being wiped out by a catastrophic disease currently spreading across the globe.
Have you ever considered whether the fruits and vegetables you see on the shelves in grocery stores are still alive? Do you think they die once they’re picked from the fields or off a tree? Research indicates that some life processes still function in vegetables such as cabbage even after they’ve been harvested.
Sparkly skin helped Edward attract Bella … but does the same thing work for plants and pollinators? New research indicates that the answer to this question is a resounding “yes.”
The National Research Council (NRC), a part of the National Academies, recently published a report that provides a detailed assessment of the impact of genetically-engineered (GE) crops on farmers. Genetically-engineered crops were first introduced to farm fields in 1996. Today, GE crops account for over 80 percent of the soybean, corn, and cotton grown in the United States. The majority of these GE crops are resistant to glyphosate (the active ingredient in RoundUp weedkiller) and make Bacillus thuringiensis, or Bt, a bacterium that is poisonous to the insects that eat it.
The NRC tied GE crops to a number of benefits, including:
- lower production costs,
- fewer pest problems,
- reduced use of pesticides, and
- greater crop yields.
A number of environmental benefits were also associated with GE crops. The greatest benefit was seen in terms of water quality. Due to the use of fewer pesticides and insecticides, hazardous chemical run-off is less of a problem at farms that grow genetically-engineered crops.
One worry of using these glyphosate-resistant GE crops is that problems with weeds could arise in the future as the weeds themselves become resistant to glyphosate. This resistance has already arisen in nine weed species since the introduction of GE crops. The report authors suggest that farmers utilizing GE crops should not make the crops themselves their only weed/insect management program. Instead, to maintain the crops’ effectiveness against weeds, it is suggested that farmers use an integrated weed management system that involves pesticides other than glyphosate. As to fending off insect pests, the NRC recommends that farmers continue to utilize EPA-mandated “refuges” in which conventional crops are grown alongside their GE crop fields. The thought behind these refuges is that the insects will opt to feed on the conventional plants and not the GE crops, thus reducing the chance of the insects becoming resistant to the inserted Bt gene.
In the report, the National Resource Council provides a number of suggestions for future studies and research. One such suggestion is to further study the impact that genetically-engineered crops have on both conventional and organic farmers. In addition, the NRC suggests that government support be made available to researchers interested in studying genetically-engineered crops that provide a public benefit, such as reduced environmental impact.
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Researchers at Pennsylvania State University have grown poplar trees that contain a gene from a very different plant: a green bean! The green bean gene causes changes in the makeup of the poplar trees lignin. Lignin is a material that is normally found together with cellulose in the woody parts of plants. Lignin is important for maintaining a plants structure and protecting the plant from microorganisms.
Plant cellulose stores a lot of energy. This energy is harvested to make ethanol, a fuel that can be used in some vehicles and for other energy needs, too. To access the energy in cellulose, workers must first break apart the lignin to get the cellulose. This process is hard and expensive to do! However, the green bean gene changes the lignin in such a way that accessing the cellulose is much easier and cheaper to do.
The Pennsylvania State University researchers found that their work has other uses, too. Some plants, such as ryegrass and clover, are not good for feeding to animals because the high amount of lignin is hard for the animals to digest. By genetically modifying these plants, their lignin would be more digestible to the animals.
Genetically modified plants must be approved by the federal Food and Drug Administration (FDA) before they can be sold and used outside of research facilities. Why do you think that is?
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Root-knot nematodes are common plant parasites that are found throughout the southern United States and across the world. These microscopic roundworms are found in the soil and on plant roots. They damage plants by feeding on root cells. The nematode’s rampant feeding on the roots can damage the plant’s root systems to the point where it can no longer absorb water and other necessary nutrients.
Root-knot nematodes are responsible for significant losses to field crops in sub-tropical regions. The most effective pesticide in the control of root-knot nematodes is methyl bromide (MeBr). This colorless and odorless gas is used as a soil fumigant. Although methyl bromide is very successful in killing microscopic parasites in the soil, it comes with a price. The use of methyl bromide has a negative impact on the environment–it has been implicated as one of the substances responsible for the depletion of the ozone layer. In addition, exposure to methyl bromide is a health risk to agricultural workers. In the United States, the use of methyl bromide has been phased out, in all but the most critical cases. However, it is still used in some third-world countries where pesticide alternatives cannot be easily accessed.
One way to overcome the need for noxious pesticides is to develop crops that are naturally pest-resistant. A team of scientists at the US Department of Agriculture-Agricultural Research Service, led by Dr. Judy Thies, are working to develop parasite-resistant vegetables. At the U.S. Vegetable Laboratory in Charleston, SC, researchers developed two varieties of parasite-resistant bell peppers.
The “Carolina Wonder” and “Charleston Belle” bell pepper varieties were made by backcrossing bell peppers to transfer the dominant N gene for root-knot nematode resistance from the “Mississippi Nemaheart” variety into the “Yolo Wonder” and “Keystone Resistant Giant” varieties. The “Carolina Wonder” and “Charleston Belle” varieties came from F3 populations derived after completing the sixth backcross.
In a study published in HortScience, a journal of the American Society for Horticultural Science, researchers tested how well the bell peppers fared when grown in areas with higher temperatures. To test their hypothesis, the scientists grew “Charleston Belle” and “Carolina Wonder” bell peppers in the higher-temperature soils of sub-tropic Florida. The researchers found that the nematode-resistant varieties did not break down when grown in hotter climates. These results indicate that the two new bell pepper varieties would be a suitable choice to grow in sub-tropic climates, reducing the need for pesticides such as methyl bromide. Currently, commercial seed companies are producing seeds for both pest-resistant varieties for use by both home and commercial growers.
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The researchers’ studies focused on certain short, single-strand sections of genes called microRNAs. These short-gene sections regulate other genes. In plants, microRNAS coordinate the growth and aging process. MicroRNAs work by stopping certain regulators from functioning. These regulators, called TCP transcription factors, influence the production of jasmonic acid, a plant hormone.
In their studies of the plant Arabidopsis thaliana (thale cress), the researchers found that when more microRNAs are present, fewer transcription factors are active. With fewer active transcription factors, smaller amounts of jasmonic acid are produced by the plant, and the plant ages at a slower rate.
So, what can be done with these findings? Because of this research, scientists now have a better understanding of what affects the aging process in plants. In the future, this information could be used to genetically modify plants to live longer or grow faster. However, scientists have only just begun to learn how gene regulation works in plants. According to Dr. Weigel, only when these processes are fully understood will scientists be able to attempt to produce plants that have certain desired characteristics.
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Suppose a species has one defense against bacterial infection, then the bacteria evolve to get around the defense. The host species will succumb to infection until another defense evolves to stop the attack. This is known as an evolutionary arms race — a continuous battle between two organisms to outdo each others tactics. Now, Tracy Rosebrock, a plant pathology student at Boyce Thompson Institute for Plant Research at Cornell University, published molecular data supporting the evolutionary arms race theory.
Tomatoes use a protein called Fen to protect themselves from an infectious bacterium, Pseudomonas syringae. Fen triggers an immune response in the tomatoes as soon as it comes across P. syringae.
Now, some strains of P. syringae produce a protein that acts like a tomato enzyme called E3 ubiquitin ligase. E3 ubiquitin ligase binds to proteins that the tomato plant should destroy. The copycat bacterial protein binds to Fen, causing tomato plant to eliminate Fen from its system. P. syringae evolved an effective way to turn off the tomato plants defensive system. The bacterium avoids detection and infects the plant.
The host resistance mechanism of the tomato against P. syringae and now the blocking of this immune response is now understood at the molecular level.
“Plant breeders often find that five or six years after their release, resistant plant varieties become susceptible because pathogens can evolve very quickly to overcome plant defenses,” notes Gregory Martin, Cornell professor of plant pathology and senior author of the research paper. Agricultural scientists and growers may need to look more often at disease resistance at molecular to mount a successful defense in the ongoing evolutionary arms race.