Effects of different management practices on arbuscular mycorrhizal fungal diversity in maize fields by a molecular approach

As obligate mutualistic symbionts, arbuscular
mycorrhizal fungi (AMF) colonize the roots of many agricultural
crops, and it is often claimed that agricultural practices
are detrimental to AMF. As a result, agroecosystems
impoverished in AMF may not get the fully expected range
of benefits from these fungi. Using molecular markers on
DNA extracted directly from soil and roots, we studied the
effects of different management practices (tillage and N
fertilization) on the AMF communities colonizing an experimental
maize field in Central Italy. Our molecular analysis
based on three different nuclear rRNA regions (18S, 28S
and ITS) allowed us to assess AMF biodiversity. Glomeraceae
members were the main colonizer, and they cooccurred
with Gigasporaceae and Paraglomus regardless
of the management practices applied. Diversisporaceae and
Entrophosporaceae members were instead detected in the Nfertilized
soils and in the untreated soil, respectively. The
results obtained indicated that the general AMF assemblages
structure and composition in the maize field plots appear to
be primarily influenced by N fertilization and, to a lesser
extent, by tillage. This study also validates the usefulness of
multiple molecular markers to consolidate and refine the
assessment of the environmental AMF diversity.