Enzyme secretion by ECM fungi and exploitation of mineral nutrients from soil organic matter

Abstract

Abstract· Introduction Important nutrients in forest soils such as nitrogen and phosphorus are mostly recycled from natural polymeric compounds contained in litter and organic debrisfor example nucleic acids, proteins, or chitin.· Objectives Activities of enzymes such as phosphatases, proteases, cellulases, chitinases and laccase were shown in saprotrophic but also in ectomycorrhizal fungi and there is increasing evidence that these enzymes contribute not only to the functioning of the symbiosis but also to the mobilisation of nutrients. In the present review, we describe how enzyme secretion and localisation on fungal hyphae may be connected to the potential role in soil nutrient cycling. · ResultsRecently developed methods for enzyme activity studies of ectomycorrhizae directly assayed in or collected from the field such as enzyme activity profiling and soil imprinting are described. Their value and limitations in different examples of ecological studies is highlighted and discussed also with respect to the role of other soil microorganisms associated with ectomycorrhizae. · ConclusionThe conclusion from our review is that enzyme activities of ECM and their associated microorganisms provide a potentially enormous plasticity of mycorrhizosphere functionality which is an open field for further research. Enzymes secrétés par les champignons ectomycorhiziens et exploitation des éléments minéraux contenus dans la matière organique du sol.

Effects of Different Ectomycorrhizal Fungal Inoculates on the Growth of Pinus tabulaeformis Seedlings under Greenhouse Conditions

“…Rhizosphere soil enzymatic activities are sensitive to perturbations associated with ECM inoculation; monitoring of the rhizosphere soil enzyme activities provides insight on plant mineralisation of important nutrient elements, such N, and P, as well as information on soil microbial activity [41,42].…”

“…This may be due to the P not having been given to host plants but to the fungi [27]. ECM fungi can synthesise many different hydrolytic enzymes (e.g., protease, chitinase, and glucosidase) that attack recalcitrant forms of soil organic matter and often increase the N supply to plants [42,44]. In our study, all ECM treatments significantly increased rhizospheric protease activity, and the protease activity of the S. grevillei treatment was higher than that of other treatments.…”

Decomposition of Leaves and Fine Roots in Three Subtropical Plantations in China Affected by Litter Substrate Quality and Soil Microbial Community

“…It is thought that they possess no degradative capability and that they are unable to decompose complex organic molecules. Some studies [60][61][62], however, suggested that arbuscular mycorrhizal fungi play an invaluable role in organic matter decomposition, as they can decay complex organic material through releasing extracellular enzymes and organic acids. For example, mycorrhizal fungi have been found to regulate the degradation of litter in tropical forest [60] or grass leaves in soil [61].…”

Secreted enzymatic activities of ectomycorrhizal fungi as a case study of functional diversity and functional redundancy

“…Among their functions, ECMf mobilize nutrients from organic compounds by secreting oxidative and hydrolytic enzymes (Read and Perez-Moreno 2003;Courty et al 2009Courty et al , 2010bPritsch and Garbaye 2010). The recent development of new methods for determining the potential enzymatic activity profiles of individual ECMs makes possible to decipher trait diversity of ECM communities (Courty et al 2005).…”