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In nature, it is often surmised that lignin is degraded almost exclusively by basidiomycetes, with minor contributions from bacteria and even fewer from ascomycetes. Yet, numerous studies underscore the ability of many ascomycetes from a wide range of taxonomic classes to degrade newly-formed and ancient lignin, sometime more efficiently than basidiomycetes. Few genomes from ascomycetes have been analyzed in relation with their potential ability to breakdown lignin; yet, these also point out a rich repertoire of enzymes with auxiliary activities suspected to participate in lignin lysis. Not surprisingly, the molecular mechanisms used by ascomycetes to break down lignin are largely unknown. Here, we review the literature on this topic. We also present potential mechanisms by which Podospora anserina, a model ascomycete well-suited to decipher how ascomycetes breakdown lignin, may do so. Owing to their huge biomass, which dominates in soils, and despite the fact that they usually are less efficient than basidiomycetes, it is most likely that ascomycetes actually play important roles in ensuring the recycling of lignin in nature. [ABSTRACT FROM AUTHOR]

• IR excited IRDye-deoxyglucose is used to image transport with minimal background. • A sensitive, time-lapse, large FOV, automated imaging was set up with µm resolution. • Both individual hyphae and mushroom tissue can be imaged with IRDye. • IRDye acquired as reactive monomers can be coupled to molecules of choice. Mycelia of saprotrophic basidiomycetes can cover large areas in nature that are typified by their heterogeneous nutrient availability. This heterogeneity is overcome by long distance transport of nutrients within the hyphal network to sites where they are needed. It is therefore key to be able to study nutrient transport and its underlying mechanisms. An IRDye-conjugate was used for the first time for imaging transport in fungi. A method was set up for time-lapse, high spatial resolution infrared imaging of IRDye-labelled deoxyglucose (IRDye-DG) in Schizophyllum commune and Agaricus bisporus. Scanning imaging visualised the tracer in individual hyphae as well as deeper tissues in mushrooms (mm-cm depth). The advantage of using fluorescence scanning imaging of IRDye in contrast to radiolabelled tracers studies, is that a higher spatial resolution and higher sensitivity (244 fg/ml) can be obtained. Moreover, it has a large field of view (25 × 25 cm) compared to microscopy (µm-mm range), allowing relatively fast and detailed imaging of large dimension samples. [ABSTRACT FROM AUTHOR]