The paper, “Synchrotron-based X-ray fluorescence microscopy enables multiscale spatial visualization of ions involved in fungal lignocellulose deconstruction,” appeared in Scientific Reports. The work was based on studies conducted at the national laboratory’s Advanced Photon Source (APS), a national synchrotron-radiation light source research facility funded by the United States Department of Energy Office of Science.
APS management selected the paper for the citation.
About 20 years ago, Goodell, Jellison and colleagues discovered a unique system that some microorganisms use to digest and recycle wood. Three orders of “brown rot fungi” have now been identified that can break down biomass, but details of the mechanism were not known. Goodell says these fungi produce enzymes and secondary metabolites whose function is not easily followed using standard techniques such as genomics. This requires use of advanced techniques to investigate very small, low-molecular-weight compounds that work their way into the cell wall, revealing the mechanics of decay in a way not seen before.
Goodell, Jellison and colleagues at the USDA Forest Products Laboratory, Northwestern University, Universidade de São Paulo, Brazil and the APS reported that synchrotron-based X-ray fluorescence microscopy (XFM) can be used to map out trace amounts of elements in decaying wood affected by these fungi. The movement and translocation of these ions is an important aspect of brown rot in softwoods and is implicated in both enzymatic and non-enzymatic decay.
XFM is an imaging technique where a beam of X-rays is directed at a specimen and the intensities of the X-rays emitted back are detected as a function of wavelength and position. Because these energies are ion-specific, researchers can map several ions simultaneously.
The authors say that while they’ve known that ion species such as potassium, calcium, manganese, iron and zinc play important roles in fungal decay mechanisms, little is known about how abundant each species is, exactly where they accumulate within fungi and the wood they attack, and their movements throughout the decay process. The researchers used XFM at the APS to map and quantify physiologically relevant ions in wood being decayed by the important structural “dry rot” brown rot fungus Serpula lacrymans Wulfen.
“In addition to having important implications for building materials, better understanding the role of ions in the fungal decay process of wood and other lignocellulose biomaterials has significance for fields ranging from plant pathology and forest ecology to carbon sequestration and sustainable biorefinery applications,” they point out.
The research team says future studies will focus on improving these methods and on using decayed samples in a humidity-controlled environment to allow imaging a living fungus as it colonizes wood cell walls and initiates degradation.