Exotic litter of the invasive plant Ligustrum lucidum alters enzymatic production and lignin degradation by selected saprotrophic fungi

Abstract

Chemical changes in leaf input to forest soils have been reported to affect decay processes. In this work, litter mass loss and decomposition constants (k) during 200 days in solid-state fermentation of the native tree Celtis tala Gill. ex Planch. and the exotic one Ligustrum lucidum Ait. with three common litter saprotrophic basidiomycetes were compared. Alterations in litter quality were characterized by solid-state 13C NMR spectroscopy, pH, soluble sugars, ammonium, proteins, and phenol content determination and were associated with extracellular lignocellulolytic enzyme production. Differences in substrate decomposition related to litter type were observed for Leratiomyces ceres, achieving a higher k in the exotic L. lucidum litter, which might be attributed to the induction of manganese peroxidase activity. Substrate preference for alkyl C and more degradation of lignified compounds were found in such substrates. Although no statistical differences in mass loss were observed for the rest of the fungi assayed, we detected changes in several of the parameters evaluated. This suggests that exotic invasions may alter ecosystem functioning by accelerating decomposition processes through an increased fungal ligninolytic activity.