Environmental Compatibility of Penicillium rubens Strain 212: Impact on Indigenous Soil Fungal Community Dynamics

Fusarium wilt causes substantial losses in many crops, and Penicillium rubens strain 212 (PO212) is a well-established biological control agent effective against several soil-borne pathogens, including the causal agents of Fusarium wilt. Before its widespread use, it is essential to assess whether applying PO212 may affect indigenous soil microbial communities. To address this, two open-field tomato trials were conducted to evaluate spatial and temporal changes in non-target soil fungal communities following the application of PO212. Fungal community profiles were monitored over one year using PCR-DGGE of fungal rDNA, and representative DGGE bands were sequenced for taxonomic confirmation. Community structure and variability were analysed using cluster analysis (UPGMA and Neighbor-Joining) and analysis of molecular variance (AMOVA) to determine the effects of treatment, sampling date, and soil depth. PO212 application did not significantly altered the composition or diversity of indigenous soil fungal communities. DGGE banding patterns and diversity indices were similar between treated and untreated soils throughout the study period. Observed community changes were driven primarily by temporal (seasonal) variation, with samples collected at 365 days clustering separately from earlier sampling dates for both treatments. AMOVA confirmed that sampling date, rather than PO212 treatment, explained most of the variance in community composition (p < 0.05). Although PO212 persisted in soil, fluctuations in other fungal populations were minor and within the range of natural seasonal variability. Overall, field application of PO212 did not disrupt indigenous soil fungal communities, supporting its environmental safety as a biocontrol agent for managing Fusarium wilt.