Nav: Home

Lateral gene transfer enables chemical protection of beetles against antagonistic fungi

July 18, 2018

Like all other living organisms, animals face the challenge of fending off enemies. Using chemical weaponry can be an effective strategy to stay alive. Instead of taking over this task themselves, many marine and terrestrial animals associate with microbial symbionts that can provide such protection. An international team of researchers led by scientists of Johannes Gutenberg University Mainz (JGU) and the Leibniz Institute for Natural Product Research and Infection Biology in Jena has discovered that bacteria associated to Lagria villosa beetles can produce an antifungal substance very similar to one found in tunicates living in the marine environment. The researchers revealed that this commonality is likely explained by the transfer of genes between unrelated microorganisms.

Lagria villosa beetles, a species introduced to South America from Africa and now an agricultural pest in Brazil, carry Burkholderia gladioli bacteria that had been previously shown to protect the insect eggs against fungal enemies. A single beetle carries not only one, but several strains of closely related B. gladioli bacteria with different abilities to produce defensive substances.

Under natural conditions, one of the strains is especially dominant in the beetles. This, however, is challenging to investigate because it is reluctant to grow if separated from the insect host. Moreover, the genome or complete set of genetic material in this strain has shrunken. "Genome reduction often happens in bacteria that have been living in tight association to a host for a long time. Yet, the presence of closely related bacteria with such different genome sizes in the same insect is unexpected and suggests that their relationship with the beetle is different," said Dr. Laura Flórez from the Institute of Organismic and Molecular Evolution (iOME) at Mainz University, who is the first author of the study. Professor Martin Kaltenpoth, one of the senior authors of the publication, added: "For the insect, leaving room for this diversity of microbial symbionts might be the key to stay protected from enemies."

The discovery of a new bioactive substance produced by the dominant strain B. gladioli Lv-StB was particularly interesting for the research team. After putting together 28,000 beetle eggs for chemical analyses, Dr. Kirstin Scherlach and Professor Christian Hertweck in Jena identified an especially interesting symbiont-produced compound which can block fungal growth. The scientists named this new compound lagriamide, after the symbionts' beetle host, Lagria. "Strikingly, lagriamide closely resembles substances that had been found before in the marine environment and that are presumably produced by microbial symbionts of tunicates," said Scherlach. How to explain this remarkable similarity in such different habitats and organisms?

By analyzing the pool of genes in the microbial community of the L. villosa beetles, Jason Kwan and his team at the University of Wisconsin in Madison, USA, identified the genes responsible for the production of lagriamide in the genome of the dominant beetle symbiont. They also found an exciting clue: these genes are located in a so called genomic island, i.e., a region that was likely inserted in the chromosome of the symbiont from an external source.

Jumping genes are a known phenomenon in bacteria and other organisms. However, this is one of the few examples in which there is direct evidence that such transfer of genetic material underlies the defensive potential of a symbiont. It is especially exciting that symbiosis and the acquisition of foreign genetic material can be a versatile means of innovation for animal defense across habitats. These findings also underscore the value of defensive symbionts for the discovery of compounds with antimicrobial properties of potential use for humans.
-end-


Johannes Gutenberg Universitaet Mainz

Related Bacteria Articles:

How bees live with bacteria
More than 90 percent of all bee species are not organized in colonies, but fight their way through life alone.
The bacteria building your baby
Australian researchers have laid to rest a longstanding controversy: is the womb sterile?
Detecting bacteria in space
A new genomic approach provides a glimpse into the diverse bacterial ecosystem on the International Space Station.
Hopping bacteria
Scientists have long known that key models of bacterial movement in real-world conditions are flawed.
Bacteria uses viral weapon against other bacteria
Bacterial cells use both a virus -- traditionally thought to be an enemy -- and a prehistoric viral protein to kill other bacteria that competes with it for food according to an international team of researchers who believe this has potential implications for future infectious disease treatment.
Drug diversity in bacteria
Bacteria produce a cocktail of various bioactive natural products in order to survive in hostile environments with competing (micro)organisms.
Bacteria walk (a bit) like we do
EPFL biophysicists have been able to directly study the way bacteria move on surfaces, revealing a molecular machinery reminiscent of motor reflexes.
Using bacteria to create a water filter that kills bacteria
Engineers have created a bacteria-filtering membrane using graphene oxide and bacterial nanocellulose.
Probiotics are not always 'good bacteria'
Researchers from the Cockrell School of Engineering were able to shed light on a part of the human body - the digestive system -- where many questions remain unanswered.
A chink in bacteria's armor
Scientists have untangled the structure of a recently discovered bacterial wall-building protein, found in nearly all bacteria.
More Bacteria News and Bacteria Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Rethinking Anger
Anger is universal and complex: it can be quiet, festering, justified, vengeful, and destructive. This hour, TED speakers explore the many sides of anger, why we need it, and who's allowed to feel it. Guests include psychologists Ryan Martin and Russell Kolts, writer Soraya Chemaly, former talk radio host Lisa Fritsch, and business professor Dan Moshavi.
Now Playing: Science for the People

#538 Nobels and Astrophysics
This week we start with this year's physics Nobel Prize awarded to Jim Peebles, Michel Mayor, and Didier Queloz and finish with a discussion of the Nobel Prizes as a way to award and highlight important science. Are they still relevant? When science breakthroughs are built on the backs of hundreds -- and sometimes thousands -- of people's hard work, how do you pick just three to highlight? Join host Rachelle Saunders and astrophysicist, author, and science communicator Ethan Siegel for their chat about astrophysics and Nobel Prizes.