Protists, functionally divided into consumers, phototrophs, and parasites act as integral components and vital regulators of microbiomes in soil–plant continuums. However, the drivers of community structure, assembly mecha- nisms, co-occurrence patterns, and the associations with human pathogens and different protistan trophic groups remain unknown. Here, we character- ized the phyllosphere and soil protistan communities associated with three vegetables under different fertilization treatments (none and organic fertiliza- tion) at five growth stages. In this study, consumers were the most diverse soil protist group, had the role of inter-kingdom connector, and were the pri- mary biomarker for rhizosphere soils which were subjected to decreasing deterministic processes during plant growth. In contrast, phototrophs had the greatest niche breadth and formed soil protistan hubs, and were the pri- mary biomarkers for both bulk soils and the phyllosphere. Parasites had minimal input to microbial co-occurrence networks. Organic fertilization increased the relative abundance (RA) of pathogenic protists and the num- ber of pathogen–consumer connections in rhizosphere soils but decreased protistan richness and the number of internal protistan links. This study advances our understanding of the ecological roles and potential links between human pathogens and protistan trophic groups associated with soil–plant continuums, which is fundamental to the regulation of soil–plant microbiomes and maintenance of environmental and human health.