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Bananas In Danger

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For a few years we have been talking about the precarious position of the global banana crop, which is almost entirely based upon a single cloned cultivar known as the Cavendish banana.  The banana you buy in Rome is identical to the one in Rochester.  And therein lies the danger:  if a fungal blight can kill one banana shrub, it can kill them all.

For decades, a fungal disease known as Panama Disease Tropical Race 4 has been wreaking havoc on banana plantations in the Eastern Hemisphere.   Even though it was first identified in Taiwanese soil samples in the early 1990s, the destructive fungus remained confined to Southeast Asia and Australia until it was confirmed in both the Middle East and Africa in 2013.  Experts continued to fear its eventual appearance in Latin America, which is the epicenter of the global banana export industry.

In August, Colombian agricultural authorities announced that laboratory tests have positively identified the presence of Tropical Race 4 in the Caribbean coastal region and declared a national state of emergency.

The infection of the banana plant does not produce bananas that are unsafe for humans.  What happens is that the infected plants eventually stop bearing fruit.

Cavendish bananas are a prime example of the dangers of growing crops with limited genetic diversity – known as monoculture.  It leaves food systems dangerously vulnerable to disease epidemics.

This has happened to the global banana crop before when the predecessor to the Cavendish banana – the Gros Michel – was mostly eradicated by another fungal outbreak.  At the moment, there is no ready replacement banana to bail out the industry, but scientists are desperately trying to breed one.  In the meantime, the world’s supply of bananas is in real danger.

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The banana is one step closer to disappearing

Photo, posted July 9, 2009, courtesy of Dabin Lambert via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Controlling Malaria Without Chemicals

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Nearly half of the world’s population lives in areas vulnerable to malaria.  The disease kills roughly 450,000 people each year, most of them children and pregnant women.  Malaria is spread by Anopheles mosquitoes and, over time, the mosquitoes have been developing resistance to the chemical insecticides that are used to control them.  In addition, there is great concern about the toxic side effects of the chemicals used on the mosquitoes.

About 30 years ago, scientists identified a type of bacteria that kills Anopheles, but the mechanism was not understood.  As a result, the bacteria could not be replicated or used as an alternative to chemical insecticides.

But now, an international research team, headed by researchers at UC Riverside, has identified the neurotoxin produced by the bacteria and has determined how it kills Anopheles.  The work is described in a paper published in Nature Communications.

It took the team 10 years to achieve a breakthrough in understanding the bacteria.  Modern gene sequencing techniques were the key.

While many neurotoxins target vertebrates and are highly toxic to humans, the neurotoxin that kills Anopheles mosquitoes does not affect humans, vertebrates, fish, or even other insects.  Known as PMP1, the substance is not even toxic to mice when given by direct injection.

The team has applied for a patent on this discovery and hopes to find partners to help them develop the bacteria-based insecticide.

There is a high likelihood that PMP1 actually evolved to kill the Anopheles mosquito.  This finding opens the door to new avenues of research into other environmentally friendly insecticides that would be targeted at other disease-spreading pests.

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Controlling deadly malaria without chemicals

Photo, posted June 9, 2018, courtesy of Mario Yardanov via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Sunlight As A Cash Crop

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It isn’t so easy to be a farmer these days.  Farming has always involved long hours, hard work and the uncertainties of weather and yield.  The 21st Century has added new and unique challenges such as increasingly unpredictable weather, insect infestation and disease, and low commodity prices.  Add in sudden tariffs and farmers struggle even more to make ends meet.  The default rate for farmers’ loans is the the highest in at least nine years.

One thing that remains reliable for farmers is the sun.  It rises in the morning and goes down at night.  The sun can be trusted, unlike politicians, rain, or commodity prices.  These days, many farmers are taking advantage of the dependability of the sun to make money from a new cash crop: solar energy.

The trend is spreading.  North Carolina has been a leading solar energy state for several years and a 2017 report found that solar energy generates 30% of the income of many farms.  Typical annual rent payments for farmland by solar companies range from $500 to $1,400 per acre in North Carolina.

A growing list of states have clean energy mandates targeting 100% use of renewable energy.   These mandates provide incentives for farmers that make installing solar a financially smart decision and falling prices for solar installations make it an even better deal.

Solar works well when co-located on a farm and can be built in ways that minimizes impact.  It is quiet, uses almost no water, doesn’t pollute, and if it is decommissioned, the land can go back to its previous use.  If the solar facilities are raised up, the same land can be used to graze livestock or grow shade-tolerant crops.

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Harvesting the sun is the new cash crop

Photo, posted December 25, 2017, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Disease On Coral Reefs

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The warming oceans have led to bleaching events in coral reefs around the world, but bleaching is not the only problem corals face.  Disease outbreaks are also becoming more frequent, severe, and widespread.

Many factors are contributing to the problem, including pollution and nitrogen runoff from fertilizers and coastal sewer and septic systems.  However, the key culprit is likely the steadily increasing ocean temperatures, which are the cause of coral bleaching.  Elevated water temperatures can cause coral polyps to expel the algae that sustains them and gives them color. 

According to scientists, bleaching makes corals more susceptible to illness.  In the Caribbean, a coral disease hotspot, about 80% of coral cover has disappeared, largely from outbreaks of “white band disease”, so called because of a white band of dead tissue that forms in affected corals.  Two crucial reef-building species, elkhorn and staghorn coral, are now nearing extinction in the regions.  The reef extending along the Florida coastline is the third largest reef ecosystem in the world and nearly 35% of it has been lost to disease.

Estimates are that disease outbreaks have wiped out at least 6% of the corals on the Great Barrier Reef in Australia.  In that region, diseases are more prevalent in areas where corals were damaged by fishing and other human activity because wounded coral provides an entry point for pathogens and bacteria.

In the face of climate change and mounting disease outbreaks, scientists are scrambling for solutions to stave off catastrophe.  Assisting the migration of hardier coral species and breeding so-called “super corals” are among the strategies being pursued.  It is unknown whether these and other forms of intervention can be used on a wide enough scale to really make a difference.

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As Disease Ravages Coral Reefs, Scientists Scramble for Solutions

Photo, posted November 29, 2012, courtesy of Robert Linsdell via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Bitter Truth About Caffeine

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Black coffee has a bitter taste. Bitterness evolved as a natural warning system to protect the body from harmful substances.  By the logic of evolution, we should therefore want to spit coffee out, but obviously it doesn’t work that way.

Caffeine itself has a particularly bitter taste.  Surprisingly, a new study at Northwestern University has found that the more sensitive people are to the bitter taste of caffeine, the more coffee they drink. That sensitivity is actually a genetic variant.

So, one would think that people who are especially sensitive to the bitter taste of caffeine would drink less coffee.  The counter intuitive result suggests that coffee consumers acquire a taste or an ability to detect caffeine as a result of the learned positive reinforcement (in other words, the buzz) elicited by caffeine.  People with a heightened ability to taste coffee’s bitterness learn to associate good things with it.

The study also found in contrast that people sensitive to the bitter flavor of a different compound called 6-n-propylthiouracil (known as PROP)avoided coffee as well as red wine.

The study made use of applied Mendelian randomization, a technique commonly used in disease epidemiology, to test the causal relationship between bitter taste and beverage consumption in more than 400,000 men and women in the United Kingdom.

These results shed some light on the disdain many coffee drinkers have for decaf coffee.  It may not be just the lack of buzz that turns them off.  Some of them with the right genes may be missing that extra bit of bitterness that alerts them that something good is about to happen.

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Why we shouldn’t like coffee, but we do

Photo, posted May 22, 2009, courtesy of Olle Svensson via Flickr.  

Earth Wise is a production of WAMC Northeast Public Radio.

Speed Breeding Of Crops

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A technique pioneered by NASA for the purpose of growing plants extra-terrestrially is now being applied here on earth to fast-track improvements in a range of crops.  The technique, known as speed breeding, has been adapted for use by British and Australian researchers on a scale ranging from vast greenhouses to desktop growth chambers.

Speed breeding uses enhanced LED lighting and day-long regimes of up to 22 hours to optimize photosynthesis and promote rapid growth of crops.  By speeding up the breeding cycle of plants,it is possible, for example, to grow six generations of wheat in a year compared with two generations using traditional breeding methods.

With shortened breeding cycles, genetic improvements such as yield gain, disease resistance and climate resistance can be fast-tracked in crops such as wheat, barley, chickpeas, various Brassica species, oil seed rape and peas.

The ability to do this in compact desktop chambers permits cutting-edge research to be performed inexpensively before being scaled up to large greenhouses.

Crop development is an increasingly important activity and speed breeding is increasingly attractive in light of the opposition in some quarters to modern gene-editing techniques to create GMO crops.  Speed breeding allows crop improvements via anon-GMO route.

The new technique is already being applied in Australia, which is experiencing one of the worst droughts on record.  It is being used to rapidly cycle genetic improvements to make crops more drought resilient.

Generation time in most plant species is a major bottleneck in applied research programs and breeding.  Speed breeding can greatly reduce this bottleneck, allowing scientists to respond more quickly to emerging diseases, the changing climate and increased demand for specific plant traits.

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JIC joins European scientists to safeguard precision breeding

Photo, posted May 8, 2016, courtesy of Yair Aronshtam via Flickr. 

Earth Wise is a production of WAMC Northeast Public Radio.

Carbon And North American Forests

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Researchers have for the first time calculated the capacity of North American forests to sequester carbon.  The detailed analysis by UC Santa Cruz and collaborators in China and Arizona considers two key factors:  the natural process of forest growth and regeneration, and effects brought about by climate change.

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Air Pollution And Diabetes

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Air pollution is deadly.  Studies have found that fine particulate matter, such as airborne pieces of dust, dirt, smoke, soot, and other microscopic particles can enter our lungs and bloodstream, contributing to major health conditions such as heart disease, stroke, cancer, and kidney disease.

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Losing Forests Is Felt Far Away

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Large areas of forests in our country are vulnerable to drought, fires and disease.  When forests are heavily damaged, there are well-known local impacts:  drier soils, stronger winds, increased erosion, loss of shade and loss of habitat.

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Pesticides And Bees

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According to a European food safety watchdog, most applications of neonicotinoids – the world’s most widely used insecticides – represent a risk to wild bees and honeybees.  The use of these insecticides has been restricted in Europe since 2014 following earlier risk assessments. 

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Reviled Animals Can Be Beneficial

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Predators and scavengers are widely persecuted by people because they are often harmful to property, livestock, and human beings.  Nonetheless, research has shown that many of these animals play important roles in ecosystems and their removal can be quite harmful.

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Climate Change And Hawaii

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The Hawaiian Islands are an archipelago of eight major islands, several atolls, numerous smaller islets, and seamounts in the North Pacific Ocean.  The islands are a world-renowned vacation spot, known for their white-sand beaches, lush flora, and near perfect weather.  But stormier days may be ahead. 

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Saving African Cattle With Perfume

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Tsetse flies are widespread in Africa. They feed on blood and are the source of the dreaded sleeping sickness, an infection that can be lethal, damages the nervous system and, in its final stage, causes a dozy state, which gave the disease its name. Sleeping sickness is a real danger for people in tropical Africa, but tsetse flies can also transfer the disease to cattle.  This leads to huge losses in milk, meat and manpower.  The damage caused by the flies in Africa is estimated to be nearly $5 billion a year.

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Genetic Engineering And Conservation

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Genetic engineering, or equivalently synthetic biology, is a multi-billion-dollar enterprise involved in pharmaceuticals, chemicals, biofuels and, of course, agriculture.  In these fields, it is already the source of a great deal of controversy.  But there is increasing interest in using synthetic biology (or synbio) technology as a tool for protecting the natural world, which is a prospect some find tantalizing and others find absolutely terrifying.

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Dangerous Diseases From The Past

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Climate change is poised to transform life on Earth as we know it.  The higher temperatures, the rising seas, the more frequent floods and droughts, among the countless other consequences associated with climate change, threaten to do irreversible damage to the world in the coming decades.

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Squeaking By

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Amphibians are one of the most threatened groups of animals on the planet.  Since the late 1980s, scientists have measured dramatic population declines from locations all over the world.  The plummeting amphibian populations are perceived to be one of the most critical threats to global biodiversity.  According to the IUCN, about 1 of every 3 amphibian species is facing extinction.  Some of the greatest threats facing amphibians include climate change, disease, and habitat destruction. 

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Livestock And Antibiotics

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According to the FDA, approximately three-quarters of all antibiotics used in the U.S. are fed to livestock for non-therapeutic purposes.  This routine administration of antibiotics promotes the development of antibiotic-resistant bacteria, which can spread to animals and humans.   And as antibiotic-resistant bacteria spreads, medicines used to treat human diseases can become less effective. Antibiotic resistant infections kill 90,000 Americans each year.

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