Effects of fungal endophytes on grass and non-grass litter decomposition rates

The influence of clavicipitaceous fungal endophytes on grass decomposition rates has been studied through field and laboratory experiments. However, the effects of endophytes on decomposition rates of non-grass species are unclear. This paper reviews research data related to the effects of fungal endophytes on decomposition rates of three litter types: grass, non-grass leaf litter (including spruce needle litter) and non-grass twigs and wood. We discuss how fungal endophytes are involved in, or regulate decomposition rates and may change lifestyles from fungal endophytes to saprotrophs. Classical morphology and molecular approaches together with digestion enzyme studies provide evidence to suggest that some endophyte species switch their ecological roles and adopt a new life style as saprotrophs. We also explore the main mechanisms that explain how fungal endophytes may decelerate decomposition rates and whether it is directly driven by alkaloids. Further research on the role of fungal endophytes in decomposition rates of both grass and non-grass litter is needed, especially those addressing the direct and indirect mechanisms by which endophytes affect decomposition rates.