Bacteriome of the soil affected by hostilities as a source of isolation of plant growth-promoting metal-resistant bacteria

Abstract Background The work is aimed at a comprehensive analysis of soil changes after a mortar shell explosion, including the study of changes in the bacteriome composition, the physical and chemical properties of the soil, and the search for plant growth-promoting (PGP) metal-resistant bacteria. Methods Soil samples from the mortar shell crater and the visually not-affected area were examined. The soil particle size distribution, humus content, and acidity were determined using conventional soil chemistry methods, and the heavy metals content – by atomic absorption spectrophotometry. Conventional microbiological methods and 16S rRNA metagenomic barcoding were used. The bacterial PGP traits were determined by the ability to synthesize siderophores and auxin-like compounds, solubilize P and Zn, fix N 2 , and improve the growth of Triticum aestivum on crater soil extract. Results In the crater soil, an increase in the fine particles content on 60% as well as Mn (1.1 times), Cu (2.1 times), Zn (1.1 times), Se (1.3 times), Pb (1.4 times), Cd (2.3 times), and As (1.2 times) were observed, while the humus content (on 1%) and hydrolytic acidity decreased. 90–92% of prokaryotic sequences were identified as Bacteria (31 phyla), the rest were Archaea ( Crenarchaeota , Thermoplasmatota , Nanoarchaeota ). Firmicutes (20.83% OTUs vs. 3.52% OTUs in the nearby site soil), Actinobacteriota (20.43% OTUs vs. 28.67% in the nearby site soil), and Proteobacteria (19.46% OTUs vs. 20.71% in the nearby site soil) dominated in the crater soil. The abundance of Thermoplasmatota in the crater soil was 0.007% OTUs (compared to 0.03% in the nearby site soil), and Nanoarchaeota were not detected. We have isolated 58 bacterial isolates resistant to Cd, Co(II), Fe(II), Mn(II), Cr(IV), Cu(II), with PGP traits. The strains with PGP traits, positively affecting wheat chlorophyll content, and resistant to all studied metals, were identified as Bacillus sp. IMV B-8154 and Streptomyces sp. IMV Ac-5058. Conclusion After a mortar shell explosion, heavy metals enter the soil, causing an average level of environmental risk, changing the soil’s physical and chemical properties, reducing bacterial diversity, and changing the bacteriome’s taxonomic structure. Graphical Abstract