Arbuscular mycorrhiza and soil nitrogen cycling

Abstract

a b s t r a c tNitrogen is a major nutrient that frequently limits primary productivity in terrestrial ecosystems. Therefore, the physiological responses of plants to soil nitrogen (N) availability have been extensively investigated, and the study of the soil N-cycle has become an important component of ecosystem ecology and biogeochemistry. The bulk of the literature in these areas has, however, overlooked the fact that most plants form mycorrhizal associations, and that nutrient uptake is therefore mediated by mycorrhizal fungi. It is well established that ecto-and ericoid mycorrhizas influence N nutrition of plants, but roles of arbuscular mycorrhizas in N nutrition are less well established; perhaps even more importantly, current conceptual models ignore possible influences of arbuscular mycorrhizal (AM) fungi on N-cycling processes. We review evidence for the interaction between the AM symbiosis with microbes and processes involved in soil N-cycling. We show that to date investigations have rather poorly addressed such interactions and discuss possible reasons for this. We outline mechanisms that could potentially operate with regards to AM fungal e N-cycling interactions, discuss experimental designs aimed at studying these, and conclude by pointing out priorities for future research.

Symbiotic relationships between soil fungi and plants reduce N2O emissions from soil

“…A potential effect of arbuscular mycorrhizal fungi (AMF) on N 2 O emissions has been hypothesized (Cavagnaro et al, 2012;Veresoglou et al, 2012a), but has, to our knowledge, never been thoroughly tested. This is surprising because AMF associate with two thirds of all land plants and are among the most abundant functional groups of soil microorganisms being present in almost any ecosystem investigated.…”

“…Several studies also show that AMF influence bacterial communities inhabiting the rhizosphere and mycorrhizosphere (Ames et al, 1984;Scheublin et al, 2010), including shifts in denitrifying communities (Amora-Lazcano et al, 1998;Veresoglou et al, 2012b). AMF influence the N cycle and can take up significant amounts of nitrogen (Hodge and Fitter, 2010;Veresoglou et al, 2012a). By reducing the availability of soluble N in the soil, AMF could also reduce denitrification and N 2 O emission rates.…”

Nutrient interactions and arbuscular mycorrhizas: a meta-analysis of a mycorrhiza-defective mutant and wild-type tomato genotype pair

“…With increasing recognition of the importance of AM in the uptake of N (Veresoglou et al 2012), this…”

Microbial Inoculants for Soil Quality and Plant Health

“…Plant nutrition for N has also been improved by the application of some fungal inoculants. Arbuscular mycorrhizal fungi that form associations with more than 80 % of plants including most crops have also been identified as a probable N mobilizer for plants (Hodge and Storer 2015;Veresoglou et al 2012). However, the contribution of arbuscular mycorrhizal fungi to plant N uptake varies widely and the reasons for the variability are still unclear and may likely be resolved by the application of genomics and metabolomics technology (Hodge and Storer 2015).…”