Maize residues changes soil fungal composition and decrease soil microbial co-ocurrence networks complexity.

Fusarium graminearum (Fg) can cause different diseases in cereals and maize crops worldwide, and a correct management of previous crop residues could decrease disease incidence and/or severity. Bacterial, fungal and Fusarium communities were studied by metabarcoding approach in 8 agricultural fields with wheat-maize rotation system in Brittany, France, during three years. Additionally, shift in microbial communities were evaluated under mesocosm experiments in soils amended or not with maize residues and/or Fg isolate. Bacterial communities composition were highly influenced by crop soil origin in both environmental and mesocosm soils, while bacteria co-occurrence network complexity was decreased by maize residues in environmental samples and Fg treatment in mesocosm samples. Maize residues altered slightly bacteria-fungi co-occurrence networks, while all treatments on mesoscosm experiments showed lower complexity in bacteria-fungi networks than Control Soil treatment. A clear input of fungal genera Epicoccum, Fusarium, Vishniacozyma, Articulospora, Papiliotrema, Sarocladium, Xenobotryosphaeria, Ramularia, Cladosporium, Cryptococcus and Bullera from maize residues to soil were observed for both environmental and mesocosm samples. Moreover, an increase of F. graminearum and F. avenaceum was observed in soils whe maize residues were presented. Finally, microbial co-occurrence networks reported some OTUs significant correlated to Fusarium spp. OTUs, such as those assigned to Epicoccum, Vishniacozyma and Sarocladium fungal genera, previously reported as efficient biocontrol agents versus Fusarium spp. Moreover, a decrease of complexity was observed for soil bacterial and bacterial-fungal networks due to maize addition in both environmental and mesocoms communities.