Arbuscular mycorrhizal fungal propagules from tillage and no-tillage systems: possible effects on Glomeromycota diversity

Abstract

Arbuscular mycorrhizal fungi (AMF) can use different types of propagules to colonize new roots. In this work we tested different types of AMF inocula obtained from a field experiment with tilled and no-tilled soils planted with wheat as well as from nondisturbed treatments with spontaneous vegetation. AMF trap cultures were carried out with soil, mycelium, segments of roots and wheat plants from the field as sources of inocula. Then after the senescence of the trap plants Glomeromycota species that had been established from each type of propagule in the substrate from the pots were identified. In field soils the proportions of Acaulosporaceae and Gigasporaceae were relatively similar to that of Glomeraceae, mainly in conventional tillage, whereas in all trap cultures investigated the percentages of members of the Glomeraceae family were higher than 90%. Because most of the trap cultures were based on intra- and/or extraradical mycelium our results show that members of Glomeraceae have advantages in the use of these propagules over Acaulosporaceae and Gigasporaceae species. We suggest that the higher contribution of Glomeraceae previously found in no-tillage systems could be related partially to the lack of disruption of the hyphal network and the composition of the soil propagules in this system.

Trap Culture Technique for Propagation of Arbuscular Mycorrhizal Fungi using Different Host Plants

“…A trap culture contains spores, hyphae and colonized root bits as an inoculum and can promote diverse AMF species. In contrast, Schalamuk and Cabello (2010) reported that trap culture inoculum favored higher propagation of Glomeraceae family while lower number of spores was obtained from other families. Therefore, we replace it to hypothesize that suitable host plants with periodic rotation may reduce the loss of AMF diversity in trap culture.…”

Characterizing and handling different kinds of AM fungal spores in the rhizosphere

“…Generally, there are three kinds of AM fungal propagules present in soils: spores, extraradical mycelium and infected root segments (Druille et al 2013;Smith and Read 2008). Extraradical mycelium is considered to be the most important source of inoculum among the species belonging to the Glomeraceae (Schalamuk and Cabello 2010). By contrast, spores are the main source of inoculum among species belonging to the Gigasporaceae because these AM fungi colonize roots primarily from spores (Schalamuk and Cabello 2010).…”

Spore Density of Arbuscular Mycorrhizal Fungi is Fostered by Six Years of a No-Till System and is Correlated with Environmental Parameters in a Silty Loam Soil

“…Although it has been shown that tillage (through aggregate disruption [4]) and N fertilization can reduce the colonization of crops by arbuscular mycorrhizal fungi [5][6][7], our knowledge of the factors that determine the successful establishment of an AMF symbiosis remains limited. Spore density of AMF together with the level of hyphal growth and branching are critical for successful root colonization [6,8]. The density of spores has been defined as an early and useful indicator of AMF colonization potential [9].…”