Termite gut holds a secret to breaking down plant biomass

In the Microbial Sciences Building at the University of Wisconsin-Madison, the incredibly efficient eating habits of a fungus-cultivating termite are surprising even to those well acquainted with the insect’s natural gift for turning wood to dust.

According to a study published today (April 17, 2017) in the journal Proceedings of the National Academy of Sciences, when poplar wood undergoes a short, 3.5-hour transit through the gut of the termite, the emerging feces is almost devoid of lignin, the hard and abundant polymer that gives plant cells walls their sturdiness. As lignin is notorious for being difficult to degrade, and remains a costly obstacle for wood processing industries such as biofuels and paper, the termite is the keeper of a highly sought after secret: a natural system for fully breaking down biomass.

“The speed and efficiency with which the termite is breaking down the lignin polymer is totally unexpected,” says John Ralph, a UW-Madison professor of biochemistry, researcher at the Great Lakes Bioenergy Research Center (GLBRC) and lignin expert. “The tantalizing implication is that this gut system holds keys to breaking down lignin using processes that are completely unknown.”

Source: Termite gut holds a secret to breaking down plant biomass – EurekAlert! Science News, 2017-04-17

Suzanne Simard: How Do Trees Collaborate?

Ecologist Suzanne Simard shares how she discovered that trees use underground fungi networks to communicate and share resources, uprooting the idea that nature constantly competes for survival.

About Suzanne Simard:
Suzanne Simard is a professor of forest ecology at the University of British Columbia. Her work demonstrated that these complex, symbiotic networks in our forests mimic our own neural and social networks. She has thirty years of experience studying the forests of Canada.

Source: Suzanne Simard: How Do Trees Collaborate? : NPR, 2017-01-13

Soil fungi help tree seedlings survive, influence forest diversity

A new paper published Jan. 13 in Science reveals that the relationship between soil fungi and tree seedlings is more complicated than previously known. The paper was co-written by Ylva Lekberg, an assistant professor of soil community ecology at the University of Montana.

Lekberg and her collaborators studied 55 species and 550 populations of North American trees. Scientists have long known that plants and soil biota can regulate one another, but the new findings highlight the complexity of the feedback loop.

“Fungi differ in their ability to protect tree seedlings from pathogens, and this has implications for seedling recruitment and therefore forest community patterns,” Lekberg said.

Most plant roots are colonized by mycorrhizal fungi, but tree species associate with different fungal groups. The researchers showed that ectomycorrhizal fungi that form a thick sheet around root tips are better able to protect trees from pathogens than arbuscular mycorrhizal fungi.

Thus, while ectomycorrhizal tree seedlings actually prefer growing next to parent trees, arbuscular mycorrhizal tree seedlings can only establish outside the control of parents’ enemies. This can have consequences for how temperate forests are structured and their overall diversity.

Source: Soil fungi help tree seedlings survive, influence forest diversity — ScienceDaily, 2017-01-13

Ash dieback: Insect threat to fungus-resistant trees

Release by University of Exeter
Ash trees which can resist the killer dieback fungus may be more vulnerable to attacks by insects, according to new research.

Scientists from the universities of Exeter and Warwick examined trees which are resistant to ash dieback and – unexpectedly – found they had very low levels of chemicals which defend against insects.

With efforts under way to protect ash trees from dieback, the scientists warn that selecting trees for fungal resistance could put them at risk from insects.

Aside from ash dieback, the other major threat to European ash trees is the Emerald Ash Borer beetle, which has already devastated vast tracts of ash in the USA and is currently spreading westwards across Europe.

Source: Ash dieback: Insect threat to fungus-resistant trees | EurekAlert! Science News

Wood Degradation by Thermotolerant and Thermophilic Fungi for Sustainable Heat Production

ACS Sustainable Chem. Eng., 2016, 4 (12), pp 6355–6361
The use of renewable biomass for production of heat and electricity plays an important role in the circular economy. Degradation of wood biomass to produce heat is a clean and novel process proposed as an alternative to wood burning, and could be used for various heating applications. So far, wood degradation has mostly been studied at ambient temperatures. However, the process needs to occur at elevated temperatures (40–55 °C) to produce useable heat. Our objective was to study wood degradation at elevated temperatures for its potential application on heat production. Two (a thermotolerant and a thermophilic) fungi with different degradation strategies were chosen: lignin-degrading Phanerochaete chrysosporium and cellulose-degrading Chaetomium thermophilum. Each fungus was inoculated on nonsterile and sterile birch woodblocks to, respectively, study their wood degradation activity with and without natural biota (i.e., microorganisms naturally present in wood). The highest wood decay rates were found with C. thermophilum in the presence of natural biota, followed by P. chrysosporium under sterile conditions. The estimated theoretical value of heat production with C. thermophilum under nonsterile conditions was 0.6 W kg–1 wood. In conclusion, C. thermophilum seems to be a promising fungus to degrade wood together with natural biota, as sterilization of wood is not feasible in practice. Further testing on a larger scale is needed to implement the obtained results and validate the potential of biological wood degradation for heat production.

Source: Wood Degradation by Thermotolerant and Thermophilic Fungi for Sustainable Heat Production – ACS Sustainable Chemistry & Engineering (ACS Publications)