Tribiome Project The influence of abiotic stressors on the wheat microbiome

The EU’s TRIBIOME project aims to assess the sustainability of food processes and enhance productivity under climate change scenarios by characterizing human, soil, animal and plant microbiomes to balance food production and ecosystems preservation. In this context we investigated soil and rhizosphere microbiome of soft (Triticum aestivum ssp. vulgare) and hard (Triticum turgidum ssp. durum) wheat under drought conditions. Samples were collected from separate soft and hard wheat fields in Italy and Spain, subjected to drought (treatment) or not (control), during a standard yearly production cycle. We focused on samples collected during the flowering phase (April 2023). A total of 272 samples, including 30 root and 4 soil samples for each condition, were processed through 16S rRNA gene metabarcoding sequencing for taxonomic and phylogenetic analysis. Our preliminary results show significant differences in root and soil microbiomes irrespective of condition or species in both countries. The microbial community α-diversity was higher in all control samples compared to treatments. However, intraregional variations showed contrasting patterns between countries. Italian rhizosphere samples highlighted a higher microbial ecosystem diversity compared to the respective soils under both control and treatment conditions, while Spain displayed an opposite trend. Moreover β-diversity analysis excluded significant differences between the rhizosphere microbiomes of hard and soft wheat; hence, we focused on the discriminant components of the microbial community between all control and treated samples regardless of plant species. Spanish treatment samples showed a significant increase of the genera Promicromonospora, Streptomyces and Variovorax while respective Italian samples showed a significant increase of the genera Microlunatus, Rubrobacter, Flavisolibacter, Pedobacter, Azospirillum and Microvirga. Species within the last two genera were observed to promote crop growth, reduce nitrogen fertilizer requirements, establish beneficial relationships with roots and perform plant growth-promoting (PGP) functions, with some Azospirillum strains described for their ability to confer plant tolerance to environmental stresses like drought. These preliminary results provide insight into shifts in the wheat microbiome in climate change dynamics, enabling knowledge on PGP microbiome activities as a useful biotechnological tool for the implementation of sustainability in food systems.