Impact of technical itineraries on the diversity and the functioning of arbuscular mycorrhizal fungi and associated microorganisms in vineyards soils and grapevine roots

Abstract

Context and purpose. The vine is a holobiont, where the plant interacts positively, negatively, and neutrally with microbes that together form the vine’s microbiome. We focused on the belowground portion of this microbiome, particularly on arbuscular mycorrhizal fungi, which are known to be essential for plant growth and health and to influence berry quality. We analyzed the soil and root microbiomes of vines, along with associated soil functions, across a wide range of agricultural practices in the Cognac region, such as grass cover and agroforestry. The purpose of this study is to understand the effects of cultivation practices on the interactions between plants, soils, and microorganisms, and to examine the functions associated with mineral nutrient cycles.

Material and method. Roots, rhizospheric soil, and grapes were sampled from 52 plots selected across the Cognac region. The diversity of total fungi, arbuscular mycorrhizal fungi, bacteria, and nematodes was studied using ITS, LSU, 16S, and 18S markers, respectively. Soils were characterized by analyzing their physicochemical properties and measuring enzymatic activities related to nutrient cycles.

Results. We observed differences in soil enzymatic activities between the studied plots, as well as variations in microbial diversity profiles both between plots and between soils and roots within a given plot. An integrated analysis was carried out to assess the relationships between soil characteristics and activities, microbial diversity, and must properties. This innovative study of the core root microbiome at a regional scale highlights highly specific characteristics depending on pedoclimatic conditions and farming practices.