Taxonomic diversity and functional adaptations indicated by the rhizospheric soil microbiome derived from Turkish wheat fields.

Optimization of the soil microbiome is a promising strategy to support sustainable crop production. With the goal of developing novel bio-fertilizers for wheat cultivation, we collected fresh soil samples from ten different fields representing wheat production regions in Türkiye. Wheat seedlings (Triticum turgidum ssp. durum) were cultivated in each soil and at the three-leaf stage, DNA was isolated from the rhizospheric soil associated with each plant and the bacterial microbiome composition determined by 16S metabarcoding. Long-read sequencing was used to maximize resolution, and 1269 high-quality operational taxonomic units (OTUs) were identified. Comparisons of wheat and non-wheat rhizospheric soil identified 77 OTUs that were enriched in the wheat rhizosphere, several belonging to taxa that have previously been described as plant growth-promoting rhizobacteria. Furthermore, 209 OTUs were present in all ten wheat fields sampled, indicating that they may be ubiquitous in wheat-growing regions of Türkiye; a subset of these were also reported in wheat rhizospheric soil from other countries. Additional taxa were shown to be enriched based on local soil conditions such as pH and macronutrient content. These findings shed light onto the essential composition of the wheat rhizospheric microbiome, which provides a foundation for the development of locally adapted bio-fertilizers.