News

Bacteria Gene Leaps Across Species Barrier

Unusual case of gene transfer found in insect coffee pest

A bacterial gene has found its way into the genetic material, or genome, of an insect called the coffee berry borer.
A bacterial gene has found its way into the genetic material, or genome, of an insect called the coffee berry borer.

Multimedia

Audio

A bacterial gene has somehow lept across the species barrier and landed in the genetic makeup of an insect.

While it's a mystery how the gene got there, it's been a big help to the insect.

The insect, called the coffee berry borer, is the bane of coffee plantations worldwide. It lives on nothing but coffee beans and causes about $500 million of damage every year.

Coffee researchers in Colombia were not looking for cases of cross-species gene swapping.

They were simply trying to figure out how the coffee berry borer drilled its way into the coffee bean.

They contacted Cornell University plant biologist Joss Rose, who had developed some scientific tools the Colombian researchers thought might help.

'Aha' moment

Working together, Rose says they discovered that the insect produces proteins in its gut that break down the main kind of sugar, or carbohydrate, that the coffee plant uses to store energy. Those sugars are called mannans, and the proteins that break it down are called mannanases.

“So we thought, ‘Aha. This is interesting,'" Rose says. "This looks like a potential mechanism. If this thing can have mannanases in its gut, it can digest the carbohydrates and chew its way in.”

Rose says there was just one problem.

“Insects don’t seem to have mannanases. We came across no other example in the literature or any of the DNA sequence databases of an insect that has a mannanase.”

Gut bacteria


Insects may not have these proteins, but the bacteria that live in their guts do.

Bacteria help all kinds of creatures - from insects to humans - digest their food. Rose and his colleagues thought maybe what they were seeing was just bacterial contamination.

But it wasn't.

“We confirmed through a number of different techniques that no, in fact, this gene actually is in the genome of the insect," he says, "and yet has all the signatures, all the sequence that looks exactly like a bacterial gene.”

How that bacterial gene got into the insect’s genetic material, or genome, is not clear, though Rose and his colleagues have a few ideas to test.

Enormous advantage

They think the beetle acquired the bacterial gene after humans domesticated the coffee bush and began growing it in larger plantations. With all those coffee beans around, Rose says, “anything that has a mannanase that allows it to drill into this bean [would] be at an enormous selective advantage.”

It certainly has been an advantage for the coffee berry borer. With the help of that bacterial gene, it can live on a diet based entirely on coffee beans.

Yale University evolutionary biologist Nancy Moran says these kinds of gene transfers may be rare but important events that help organisms adapt to new environments.

Not so unusual


Just a few years ago, she and her colleagues were studying another plant pest, the aphid. Aphids produce colored chemicals that serve as camouflage and sunscreen. The researchers discovered that the genes for the proteins that make those chemicals came from a fungus.

“There’s a tendency when people find something that seems very unusual and strange at first, often it does turn out that it’s not that unusual and that it’s actually more widespread,” she says.

It is unclear just how widespread it is. Moran says she does not know of any cases farther up the food chain - of genes jumping from microbes to mammals, for example. But for the coffee berry borer at least, a little bacterial DNA seems to have made all the difference.

This forum has been closed.
Comments
     
There are no comments in this forum. Be first and add one

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
Colombians Flee Venezuela as Border Crisis Escalatesi
X
August 27, 2015 2:08 AM
Hundreds of Colombians have fled Venezuela since last week, amid an escalating border crisis between the two countries. Last week, Venezuelan President Nicolas Maduro ordered the closure of a key border crossing after smugglers injured three Venezuelan soldiers and a civilian. The president also ordered the deportation of Colombians who are in Venezuela illegally. Zlatica Hoke reports.
Video

Video Colombians Flee Venezuela as Border Crisis Escalates

Hundreds of Colombians have fled Venezuela since last week, amid an escalating border crisis between the two countries. Last week, Venezuelan President Nicolas Maduro ordered the closure of a key border crossing after smugglers injured three Venezuelan soldiers and a civilian. The president also ordered the deportation of Colombians who are in Venezuela illegally. Zlatica Hoke reports.
Video

Video Is China's Economic Data Accurate?

Some investors say China's wild stock market gyrations have been made worse by worries about the reliability of that nation's economic data. And some critics say the reports can mislead investors by painting an unrealistically-strong picture of the economy. A key China scholar says Beijing is not fudging ((manipulating)) the numbers, but that the economy is evolving quickly from smoke-stack industries to services, and the ways of tracking new economic activity are falling behind the change. V
Video

Video Next to Iran, Climate at Forefront of Obama Agenda

President Barack Obama this week announced new initiatives aimed at making it easier for Americans to access renewable energy sources such as solar and wind. Obama is not slowing down when it comes to pushing through climate change measures, an issue he says is the greatest threat to the country’s national security. VOA correspondent Aru Pande has more from the White House.
Video

Video Shipping Containers Provide Experimental Housing

Housing prices around the San Francisco Bay area are out of reach for many people, so some young entrepreneurs, artists and tech industry workers are creating their own houses using converted shipping containers. But as VOA's Mike O’Sullivan reports from Oakland, the effort requires ingenuity and dealing with restrictive local laws.
Video

Video Arctic Draws International Competition for Oil

A new geopolitical “Great Game” is underway in earth’s northernmost region, the Arctic, where Russia has claimed a large area for resource development and President Barack Obama recently approved Shell Oil Company’s test-drilling project in an area under U.S. control. Greg Flakus reports.
Video

Video Philippine Maritime Police: Chinese Fishermen a Threat to Country’s Security

China and the Philippines both claim maritime rights in the South China Sea.  That includes the right to fish in those waters. Jason Strother reports on how the Philippines is catching Chinese nationals it says are illegal poachers. He has the story from Palawan province.
Video

Video Technique May Eliminate Drill-and-Fill Dental Care

Many people dread visiting dentists because they're afraid of drills. Now, however, a technology developed by a British firm promises to eliminate the need for mechanical cleaning of dental cavities by speeding a natural process of tooth repair. VOA’s George Putic reports.
Video

Video China's Spratly Island Building Said to Light Up the Night 'Like A City'

Southeast Asian countries claim China has illegally seized territory in the Spratly islands. It is especially a concern for a Philippine mayor who says Beijing is occupying parts of his municipality. Jason Strother reports from the capital of Palawan province, Puerto Princesa.
Video

Video Ages-old Ice Reveals Secrets of Climate Change

Ice caps don't just exist at the world's poles. There are also tropical ice caps, and the largest sits atop the Peruvian Andes - but it is melting, quickly, and may be gone within the next 20 years. George Putic reports scientists are now rushing to take samples to get at the valuable information about climate change locked in the ice.
Video

Video French Experiment in Integrating Roma Under Threat

Plans to destroy France’s oldest slum have sparked an outcry on the part of its Roma residents. As Lisa Bryant reports from the Paris suburb of La Courneuve, rights groups argue the community is a fledgling experiment on integrating Roma who are often outcasts in many parts of Europe.
Video

Video Kenyans Turn to Agriculture for Business

Each year Kenyan universities continue to churn out graduates for the job market despite the already existing high rate of unemployment among youth in the country. Some of these young men and women have realized that agriculture can be as rewarding as any other business or job, and they are resorting to agribusiness in large numbers as a way of tackling unemployment. Rael Ombuor reports for VOA.
Video

Video First Women Graduate Elite Army Ranger School

Two women are making history for the U.S. Army by proving they are among the toughest of the tough. VOA's Carla Babb reports from Fort Benning, Georgia as 94 men and those two women rise as graduates of the difficult Ranger school.

VOA Blogs