The plant-associated microbiome plays a crucial role in enhancing agricultural productivity and ecosystem health. Thinopyrum intermedium, a perennial wheatgrass, offers potential ecosystem services but information about its microbiome. In the frame of the EU co-funded Biodiversa project NAPERDIV, we investigated the rhizomicrobiome of T. intermedium to assess biodiversity benefits compared to annual winter wheat.
Using a metagenomic approach, rhizosphere soil samples were collected from T. intermedium and annual wheat fields across Sweden, Belgium, and France, spanning a North-South agro-climatic gradient over two years (2021–2022). Bacterial 16S rRNA genes were amplified, and bioinformatics analyses were conducted. We integrated our data with an agroecological database based on four indicators (rhizosphere, grassland, organic matter, no-tillage) to understand the generalizability of our findings. Also, we tested the potential of T. intermedium to ensure year-on-year stability of the rhizomicrobiome using Bray Curtis dissimilarity.
Results indicated no significant differences in alpha diversity between the two crops, although T. intermedium hosted more amplicon sequence variants (ASVs). Beta diversity was more influenced by country, sampling depth, and sampling year than by crop type. Comparison with root endophytes showed that in both plants, the rhizomicrobiome was more diverse, affirming existing understanding that the endophytes are a subset of the rhizomicrobiome. Comaprison with the agroecological database revealed that the rhizomicrobiome of T. intermedium hosted more taxa associated with grasslands, organic matter, rhizosphere, and no-till practices. We confirmed that the rhizomicrobiome associated with T. intermedium was significantly stable compared to annual wheat based on year-on-year assessment.
Overall, we found considerable similarities in the rhizomicrobiome of T. intermedium and annual wheat, suggesting minor influence of perenniality on the rhizomicrobiome. This study is the first to analyze the rhizomicrobiome of T. intermedium in a European context, providing additional insights into understanding the influence of perennialization on rhizomicrobiome.