Crop yield decrease is the main concern when a pathogen or plague is identified in an agriculture field. Thus, part of this issue can be attributed to plant-parasitic nematodes (PPNs), such as Meloidogyne species, due to, most of the time, the hard diagnosis, and non-specific symptoms. Its management is mainly based on chemical pesticides, followed by a few potential biological control agents, and the management system. Therefore, this study aimed to evaluate the effects of biological agents in Meloidogyne incognita control in different soil systems. For that, two biological products were chosen, Trichoderma asperellum BV10 and Bacillus amyloliquefaciens BV03, and soils were sampled from three different managements systems: (i) soybean no-tilled system at Goiás state, Brazil; (ii) forest soil at Goiás state, Brazil, and (iii) soybean conventional managed system at Mato Grosso do Sul state, Brazil. Biocontrol and growth promotion effects, volatile organic compounds (VOCs) and soil respiration were determined in vegetation house and laboratory, respectively. As a result, both BV10 and BV03 had significant nematode control activity, comparing to control treatment, in all the three soils systems. Plus, the number of immobile nematodes by potential VOCs had significant increase when BV03 was applied, while the application of BV10 agent raised the soil respiration rate. In conclusion, both biocontrol agents presented great efficiency in control M. incognita, with better performance of BV03. Lastly, more studies must be done to elucidate how the resident soil microbiome can influence on biocontrol agent establishment and performance, as well as the consequence of the application of biological products on soil microbiome network.

Background Phosphorus (P) availability is the main nutritional factor that limits crops yields in tropical soils due to edaphic processes that lead to P immobilization after mineral fertilization. Considering the potential of the rhizosphere microbiome to transform insoluble P into forms readily available for plant uptake, in this study is proposed that plants with contrasting P uptake efficiency, growing under depleted amounts of P are able to shape distinct bacterial communities in the rhizosphere enriching taxa specialized in P mobilization. Methods We selected two common bean genotypes contrasting in P efficiency uptake and grew them in a soil with a gradient of two different sources of P, triple superphosphate (TSP) or rock phosphate Bayovar (RPB). The rhizosphere bacterial community was assessed by 16S rRNA amplicon sequencing. Data analyses focused in describing the structure of the bacterial communities, identification of OTUs differentially enriched in different treatments, functional metagenomic prediction and cooccurrence network. Results P sources and levels resulted in different rhizosphere bacterial community structure. A high number of differentially enriched OTUs were observed under P depleted conditions in the P-inefficient genotype, mainly belonging to Actinobacteria phylum. The P-inefficient genotype did not show significant differences in the rhizosphere bacterial community assembly growing in different P sources. Predicted metagenome profiles showed the enrichment of bacterial functions involved in P mobilization, in the rhizosphere of the P inefficient genotype cultivated in P depleted conditions. The network analysis revealed that in the rhizosphere of the P-inefficient genotype under P depleted conditions the bacterial community has a higher number of nodes and edges, higher average degree and clustering coeficient when compared to the treatment with optimal P level. Conclusion Our data showed that the uptake of exogenous input resulted in the assembly of a P-competent microbiome in the P-inefficient genotype compared to the efficient one, supporting the hypothesis that the selective pressure for the P uptake engages P-inefficient genotypes in symbiotic relationships with the soil microbiome. These results will pave the way for future experimentation aiming at explore the contribution of this P-competent microbiome to plant growth and development in a range of soil type.