Toward a sustainable maize cropping: X-omics support the understanding of the effects of some biotechnological practices

The adoption of more sustainable practices in maize cropping may be hampered by the challenges posed by climate change if the same do not also improve the resilience of the system to more stressing environment. The exploitation of beneficial microorganisms as bioinoculants appears as an environmental-friendly biotechnological tool in maize cropping as they can reduce requirements of inorganic fertilizers by positively influencing soil fertility. Biochar addition to soil is a promising strategy for climate change mitigation and soil fertility improvement. The objectives of this study were to unravel the synergistic effect of co-applied biochar and synthetic microbial consortia (SMC) or arbuscular mycorrhizal fungi on maize growth, soil microbiome and grain metabolome. Field experiments were carried out in two growing seasons in Italy. At different vegetative growth stages, both physiological parameters and soil chemical composition were evaluated. At harvest, yield performance was assessed, and maize kernels were collected to perform global metabolomic profiling. Rhizosphere microbial ecosystem was investigated by 16S metabarcoding sequencing and bioinformatic tools. SMC application did not significantly affect the microbial communities in terms of diversity and richness of species, with a low risk of a long-term impact on the ecology of the indigenous microbial population. However, biochar exerted a great impact on rhizosphere soil microbiome, suggesting that functionalization of biochar with SMC seems a promising approach for microbiome modulation and for enhancing plant growth also in limiting environments. Larger effects were found on the grain at metabolomic level on the presence of different fatty acids, aminoacids, and lipids.