Diversity of arbuscular mycorrhizal fungi in apple orchards under different agricultural management systems

Arbuscular mycorrhizal fungi (AMF) are beneficial soil symbionts accomplishing key functions in the complex networks of belowground/aboveground biotic interactions, as they live in association with the roots of most plant families, including fruit trees. AMF deliver many essential agroecosystem services, representing fundamental elements of soil fertility and productivity in low-input agricultural systems. However, little is known on the biodiversity of AMF communities in relation to agricultural practices in apple orchards. In South Tyrol, where the great majority of Italian apple production is located, many growers adopt integrated fruit production management techniques, while organic and biodynamic management systems are increasing. In this work different molecular tools, such as molecular cloning and sequencing techniques of partial SSU rDNA gene, as well as denaturing gradient gel electrophoresis (PCR-DGGE) were used to gain knowledge on the structure and dynamics of AMF communities in integrated, organic and biodynamic apple orchards in South Tyrol. The sequence types detected corresponded to both known and unknown AMF species, including Glomus, Rhizophagus, Funneliformis, Diversispora, Claroideoglomus and Paraglomus species. The data obtained utilising both molecular techniques showed that the different farming systems were able to shape AMF communities in apple orchards, suggesting that low-input agricultural systems, where AMF diversity is higher, may benefit from mycorrhizal symbioses in terms of soil fertility and ecosystem services.