Biotechnological aspects of the formation of the metagenome of potato rhizosphere microorganisms under the influence of microbial preparations

The study aimed to assess the impact of microbial preparations on the structural and functional characteristics of the potato rhizosphere metagenome and the associated changes in plant growth and productivity. Within the framework of the vegetation experiment, whole-genome metagenomic profiles of the potato rhizosphere were obtained for five variants: untreated, three separate microbial preparations, and their combination. A total of 11.8 million sequencing reads were obtained, which underwent basic quality filtering; 2,950 taxonomic units were identified, taxonomic and functional annotation was performed, diversity indices were calculated, and a correlation analysis with morphological and yield indices was conducted. The study determined that representatives of the Proteobacteria, Actinobacteriota, Bacteroidota and Firmicutes types dominated in all variants, with a total share exceeding 80% of the metagenome structure, while the use of microbial preparations was accompanied by an increase in species richness and diversity: the Shannon index increased from 4.82 in the control to 5.12-5.18 in the experimental variants, and the Chao1 richness estimate increased from 830 to 960-975 taxa. An increase in the proportion of genera associated with plant growth was observed, as well as in the relative number of genes associated with nitrogen fixation, phosphorus mobilisation, potassium transport, sulphur assimilation and stress resistance, with maximum values in the variants with the third preparation and its combination with the first. These options ensured an increase in tuber weight per plant to 495-510 g and an increase in the proportion of medium and large fractions of the harvest, with correlation coefficients between the total proportion of beneficial microorganisms, functional genes and productivity reaching 0.6-0.7. The results obtained showed that targeted microbial treatment can form a rhizosphere metagenome with increased biotechnological potential and can be used by practising agronomists, developers of microbial preparations, potato breeders, and specialists in integrated soil fertility management to optimise microbial consortia in potato cultivation technologies