MODULAÇÃO DA MICROBIOTA DO SOLO POR BIOESTIMULANTE ASSOCIADO À ADUBAÇÃO MINERAL: UMA ABORDAGEM POR METABARCODING DE 16S rRNA e ITS

Abstract

The application of biostimulants has been highlighted as a promising strategy to modulate soil microbiota and increase the resilience of agricultural systems. This study evaluated the effects of mineral fertilization (0, 50 %, and 100 % of the recommended rate) and the biostimulant Vitacomplex on the structure and diversity of soil fungal and bacterial communities in a greenhouse experiment. A completely randomized design was used, with five treatments and eight replicates (40 experimental units), combining mineral fertilization levels with the presence/absence of Vitacomplex. Soil sampling was performed at 90 days after sowing (DAS) for molecular characterization of microbial communities by DNA sequencing targeting the bacterial 16S rDNA and fungal ITS regions, followed by relative abundance analyses, hierarchical clustering/heatmaps, and alfa-diversity metrics (richness, Shannon, and Simpson). The results indicated dominance of Ascomycota and Basidiomycota in the fungal community and an increase in potentially beneficial taxa in the Vitacomplex treatments (e.g., Trichoderma sp., Chaetomium sp., and Clonostachys sp.), whereas the control showed a higher proportion of genera associated with potential phytopathogenicity (e.g., Fusarium sp. and Alternaria sp.). For bacteria, predominant division included Proteobacteria, Actinobacteria, and Firmicutes, with enrichment of functional genera in the Vitacomplex treatments (e.g., Bacillus sp., Streptomyces sp., Paenibacillus sp., and Rhizobium sp.). The highest microbial richness (fungi and bacteria) was observed in the 50 % fertilization + Vitacomplex treatment, suggesting that partial reduction of mineral fertilizer, when associated with the biostimulant, may favor the taxonomic diversity of the soil microbiota, with greater relative abundance of taxa associated with relevant ecological functions.