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How leaf-cutter ants cultivate fungal gardens to destroy plants and supply insights into future biofuels

Scientists have spent a long time finding ways to efficiently and cheaply degrade plant materials to show them into useful bioproducts that profit on a regular basis life.

Bio-based fuels, detergents, dietary supplements, and even plastics are the results of this work. And while scientists have found ways to degrade plants to the extent needed to provide products, some polymers similar to lignin, the major component in plant cell partitions, are incredibly difficult. That they break down cheaply without adding back pollutants. the environment. These polymers might be left behind as waste products without further use.

A specialized microbial community consisting of fungi, leafcutter ants, and bacteria is thought to naturally degrade plants, turning them into nutrients and other components that might be absorbed and utilized by surrounding organisms and systems. are But identifying all of the components and biochemical reactions required for this process has been a big challenge – until now.

As a part of her Department of Energy (DOE) Early Career Award, Kristin Barnum-Johnson, Science Group Leader for Functional and Systems Biology at Pacific Northwest National Laboratory (PNNL), and a team of fellow PNNL researchers developed an imaging method called Metabolome. Informed Proteome Imaging (MIPI). This method allows scientists to look right down to the molecular level and see which key components are a part of the plant's decomposition process, in addition to what, when, and where the important thing biochemical reactions occur that drive it. Make it possible.

Using this method, the team revealed key metabolites and enzymes that catalyze various biochemical reactions which can be necessary within the degradation process. They also revealed the aim of the resident bacteria within the system – to make the method more efficient. These insights might be applied to the event of future biofuels and bioproducts.

The team's research was recently published.

A symbiotic relationship between leaf-cutter ants and fungi reveals the important thing to success in plant degradation.

For its research, the team studied a style of fungus known for its symbiotic relationship with a species of leafcutter ants — a fungus called Leucoagaricus gongylophorus. Ants use the fungus to cultivate a fungal garden that degrades plant polymers and other materials. The ingredients left over from this decomposition process are used and consumed by a wide range of organisms within the garden, allowing all to thrive.

Ants accomplish this process by cultivating the fungus on fresh leaves in special underground structures. These structures eventually turn out to be fungal gardens that eat the fabric. Resident bacterial members aid in decomposition by producing amino acids and vitamins that support the general garden ecosystem.

“Ecosystems have evolved over millions of years to become perfect symbiotic systems,” Barnum Johnson said. “How can we best learn from these systems by observing how they naturally accomplish these tasks?”

But what makes this fungal community so difficult to check is its complexity. While plants, fungi, ants, and bacteria are all energetic components within the technique of plant decomposition, none of them give attention to one task or live in a single place. Factor within the small scale of biochemical reactions occurring on the molecular level, and an incredibly difficult puzzle presents itself. But the brand new MIPI imaging method developed at PNNL allows scientists to see what's happening throughout the degradation process.

“We now have the tools to fully understand the complexities of these systems and look at them as a whole for the first time,” Barnum Johnson said.

Showing the major components in a posh system

Using a high-powered laser, the team scanned 12-micron-thick sections of the fungal garden — concerning the width of plastic cling film. This process helped determine the locations of metabolites within the samples, that are residual products of plant degradation. This technique also helped discover the situation and abundance of plant polymers similar to cellulose, xylan, and lignin, in addition to other molecules in specific regions. Joint locations of those components indicated hot spots where plant material was broken down.

From there, the team entered these regions to take a look at enzymes, that are used to initiate biochemical reactions in living systems. By knowing the sort and placement of those enzymes, they may determine which microbes were a part of the method.

All of those components together helped confirm fungi as the first degrader of plant material within the system. In addition, the team determined that bacteria within the system converted previously digested plant polymers into metabolites which can be utilized in the system as vitamins and amino acids. These vitamins and amino acids profit the whole ecosystem by accelerating fungal growth and plant decomposition.

Barnum Johnson said that if scientists had used other, more traditional methods that measured large numbers of basic components in a system, similar to metabolites, enzymes, and other molecules, they might simply have obtained a mean of those materials. which creates more noise and hides information. .

“This reduces the critical chemical reactions of interest, often making these processes undetectable,” he said. “To analyze the complex ecosystem of these fungal communities, we need to understand these finely detailed interactions. These findings can then be taken into a laboratory setting and used to create biofuels and bioproducts. which are important in our daily lives.”

Using knowledge of complex systems for future fungal research

Marija Velkovic, a chemist and lead creator of the paper, said she was initially inquisitive about studying the fungal garden and the way it degrades lignin based on the issue of the project.

“Fungal gardens are most interesting because they are a complex ecosystem consisting of multiple members that work effectively together,” he said. “I really wanted to map activities at the micro-scale level to better understand the role of each member in this complex ecosystem.”

Velkovich conducted all experiments within the lab, collected material for slides, scanned samples to see and discover metabolites in each fraction, and identified hotspots of lignocellulose degradation.

Both Velickovic and Burnum-Johnson said they were enthusiastic about their team's success.

“We actually did what we set out to do,” Barnum Johnson said. “Especially in science, it's not guaranteed.”

The team plans to make use of their findings for further research, with specific plans to check how fungal communities react and protect themselves amid disturbances and other perturbations.

“We now understand how these natural systems degrade plant material very well,” Barnum Johnson said. “By looking at complex ecosystems at this level, we can understand how they are carrying out this activity and exploit it to make biofuels and bioproducts.”

This work was funded by DOE's Office of Science. Additionally, the researchers had access to mass spectrometry imaging and computing and proteomics resources on the Environmental Molecular Sciences Laboratory, an Office of Science user facility situated at PNNL.