Reprogrammed endophytic microbial community in maize stalk induced by Trichoderma asperellum biocontrol agent against Fusarium diseases and mycotoxin accumulation.

Maize stalk rot and ear rot, caused by Fusarium graminearum and Fusarium verticillioides, respectively, are major diseases that threaten the sustainable production of maize. In this study, an artificial inoculation assay demonstrated that the control efficacy of maize stalk rot and ear rot by Trichoderma asperellum granules were 49.83 % and 39.63 %, respectively. By high-throughput sequencing of maize plants, a total of 76 196 ITS1 sequences and 887 226 V3V4 16S rRNA sequences were analyzed and were grouped into 2934 fungal and 24 248 bacterial operational taxonomic units (OTUs), respectively. It revealed a significantly higher endophytic microbial abundance in the stem tissue of plants grown in T. asperellum-treated soil than in those grown in the control, with the largest increase observed in the basal stem section. In addition, the endophytic microbial diversity and corresponding control effects all gradually decreased from the basal to apical parts of the stem in plants grown in Trichoderma-treated soil, indicating that Trichoderma stimulated a more significant effect on the defense system in the basal section of the stalk than in the apical parts of plants. Furthermore, the accumulation of deoxynivalenol (DON) and fumonisin B1 (FB1) decreased in the stem and ear of maize grown in T. asperellum-treated soil.